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Sample records for exam mlc reserved

  1. Skin self-exam

    MedlinePlus

    Skin cancer - self-exam; Melanoma - self-exam; Basal cell cancer - self-exam; Squamous cell - self-exam; Skin mole - self-exam ... Experts do not agree on whether or not skin self-exams should be performed. So there is ...

  2. 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…

  3. 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…

  4. 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.

  5. 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…

  6. 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?

  7. 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…

  8. 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)

  9. Testicular self-exam

    MedlinePlus

    Testicular self-exam is an examination of the testicles that you do on yourself. ... The testicles (also called the testes) are the male reproductive organs that produce sperm and the hormone testosterone. They ...

  10. 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 ...

  11. Breast self-exam

    MedlinePlus

    Self-examination of the breast; BSE; Breast cancer - BSE; Breast cancer screening - self exam ... American Cancer Society. Recommendations for early breast cancer detection in women without breast symptoms. Revised October 20, ... ...

  12. Exam Question Exchange.

    ERIC Educational Resources Information Center

    Alexander, John J.

    1979-01-01

    Describes an exam question which challenges college freshmen, enrolled in chemistry, to derive temperature dependence of an equilibrium constant. The question requires cognitive response at the level of synthesis. (Author/SA)

  13. Modeling the Agility MLC in the Monaco treatment planning system.

    PubMed

    Snyder, Michael; Halford, Robert; Knill, Cory; Adams, Jeffrey N; Bossenberger, Todd; Nalichowski, Adrian; Hammoud, Ahmad; Burmeister, Jay

    2016-01-01

    We investigate the relationship between the various parameters in the Monaco MLC model and dose calculation accuracy for an Elekta Agility MLC. The vendor-provided MLC modeling procedure - completed first with external vendor participation and then exclusively in-house - was used in combination with our own procedures to investigate several sets of MLC modeling parameters to determine their effect on dose distributions and point-dose measurements. Simple plans provided in the vendor procedure were used to elucidate specific mechanical characteristics of the MLC, while ten complex treatment plans - five IMRT and five VMAT - created using TG-119-based structure sets were used to test clinical dosimetric effects of particular parameter choices. EDR2 film was used for the vendor fields to give high spatial resolution, while a combination of MapCHECK and ion chambers were used for the in-house TG-119-based proced-ures. The vendor-determined parameter set provided a reasonable starting point for the MLC model and largely delivered acceptable gamma pass rates for clinical plans - including a passing external evaluation using the IROC H&N phantom. However, the vendor model did not provide point-dose accuracy consistent with that seen in other treatment systems at our center. Through further internal testing it was found that there existed many sets of MLC parameters, often at opposite ends of their allowable ranges, that provided similar dosimetric characteristics and good agreement with planar and point-dose measurements. In particular, the leaf offset and tip leakage parameters compensated for one another if adjusted in opposite directions, which provided a level curve of acceptable parameter sets across all plans. Interestingly, gamma pass rates of the plans were less dependent upon parameter choices than point-dose measurements, suggesting that MLC modeling using only gamma evaluation may be generally an insufficient approach. It was also found that exploring all

  14. The Simple Economics of Exams.

    ERIC Educational Resources Information Center

    Adnett, Nick

    1988-01-01

    Stating that exam preparation can be an effective way of consolidating basic economic principles, Adnett presents three examples that provide an alternative approach to briefing students on good examination technique. Methods include the supply-side case for easier exams, the case of the disappearing exam, and optimal allocation of exam time. (GEA)

  15. 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.

  16. 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)

  17. 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)

  18. SU-E-T-545: MLC Distance Travelled as a Predictor for Motor Failure

    SciTech Connect

    Stathakis, S; Defoor, D; Linden, P; Kirby, N; Papanikolaou, N; Mavroidis, P

    2015-06-15

    Purpose: To study the frequency of Multi-Leaf Collimator (MLC) leaf failures, investigate methods to predict them and reduce linac downtime. Methods: A Varian HD120 MLC was used in our study. The hyperterminal MLC errors logged from 06/2012 to 12/2014 were collected. Along with the hyperterminal errors, the MLC motor changes and all other MLC interventions by the linear accelerator engineer were recorded. The MLC dynalog files were also recorded on a daily basis for each treatment and during linac QA. The dynalog files were analyzed to calculate root mean square errors (RMS) and cumulative MLC travel distance per motor. An in-house MatLab code was used to analyze all dynalog files, record RMS errors and calculate the distance each MLC traveled per day. Results: A total of 269 interventions were recorded over a period of 18 months. Of these, 146 included MLC motor leaf change, 39 T-nut replacements, and 84 MLC cleaning sessions. Leaves close to the middle of each side required the most maintenance. In the A bank, leaves A27 to A40 recorded 73% of all interventions, while the same leaves in the B bank counted for 52% of the interventions. On average, leaves in the middle of the bank had their motors changed approximately every 1500m of travel. Finally, it was found that the number of RMS errors increased prior to an MLC motor change. Conclusion: An MLC dynalog file analysis software was developed that can be used to log daily MLC usage. Our eighteen-month data analysis showed that there is a correlation between the distance an MLC travels, the RMS and the life of the MLC motor. We plan to use this tool to predict MLC motor failures and with proper and timely intervention, reduce the downtime of the linac during clinical hours.

  19. Spatial dependence of MLC transmission in IMRT delivery

    NASA Astrophysics Data System (ADS)

    Lorenz, Friedlieb; Nalichowski, Adrian; Rosca, Florin; Kung, Jong; Wenz, Frederik; Zygmanski, Piotr

    2007-09-01

    In complex intensity-modulated radiation therapy cases, a considerable amount of the total dose may be delivered through closed leaves. In such cases an accurate knowledge of spatial characteristics of multileaf collimator (MLC) transmission is crucial, especially for the treatment of large targets with split fields. Measurements with an ionization chamber, radiographic films (EDR2, EBT) and EPID are taken to characterize all relevant effects related to MLC transmission for various field sizes and depths. Here we present a phenomenological model to describe MLC transmission, whereby the main focus is the off-axis decrease of transmission for symmetric and asymmetric fields as well as on effects due to the tongue and groove design of the leaves, such as interleaf transmission and the tongue and groove effect. Data obtained with the four different methods are presented, and the utility of each measurement method to determine the necessary model parameters is discussed. With the developed model, it is possible to predict the relevant MLC effects at any point in the phantom for arbitrary jaw settings and depths.

  20. 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.

  1. Monte Carlo study of MLC fields for cobalt therapy machine

    PubMed Central

    Ayyangar, Komanduri M.; Rani, Roopa A.; Kumar, Anil; Reddy, A. R.

    2014-01-01

    An automated Multi-Leaf Collimator (MLC) system has been developed as add-on for the cobalt-60 teletherapy machines available in India. The goal of the present computational study is to validate the MLC design using Monte Carlo (MC) modeling. The study was based on the Kirloskar-supplied Phoenix model machines that closely match the Atomic Energy of Canada Limited (AECL) theratron-80 machine. The MLC is a retrofit attachment to the collimator assembly, with 14 non-divergent leaf pairs of 40 mm thick, 7 mm wide, and 150 mm long tungsten alloy plates with rounded edges and 20 mm tongue and 2 mm groove in each leaf. In the present work, the source and collimator geometry has been investigated in detail to arrive at a model that best represents the measured dosimetric data. The authors have studied in detail the proto-I MLC built for cobalt-60. The MLC field sizes were MC simulated for 2 × 2 cm2 to 14 × 14 cm2 square fields as well as irregular fields, and the percent depth dose (PDD) and profile data were compared with ROPS† treatment planning system (TPS). In addition, measured profiles using the IMATRIXX system‡ were also compared with the MC simulations. The proto-I MLC can define radiation fields up to 14 × 14 cm2 within 3 mm accuracy. The maximum measured leakage through the leaf ends in closed condition was 3.4% and interleaf leakage observed was 7.3%. Good agreement between MC results, ROPS and IMATRIXX results has been observed. The investigation also supports the hypothesis that optical and radiation field coincidence exists for the square fields studied with the MLC. Plots of the percent depth dose (PDD) data and profile data for clinically significant irregular fields have also been presented. The MC model was also investigated to speed up the calculations to allow calculations of clinically relevant conformal beams. †Radiation Oncology Planning System (ROPS) is supplied by Tirumala Jyothi Computer Systems described at https

  2. Management of the interplay effect when using dynamic MLC sequences to treat moving targets.

    PubMed

    Court, Laurence E; Wagar, Matthew; Ionascu, Dan; Berbeco, Ross; Chin, Lee

    2008-05-01

    Interplay between organ motion and leaf motion has been shown to generally have a small dosimetric impact for most clinical intensity-modulated radiation therapy treatments. However, it has also been shown that for some MLC sequences there can be large daily variations in the delivered dose, depending on details of patient motion or the number of fractions. This study investigates guidelines for dynamic MLC sequences that will keep daily dose variations due to the interplay between organ motion and leaf motion within 10%. Dose distributions for a range of MLC separations (0.2-5.0 cm) and displacements between adjacent MLCs (0-1.5 cm) were exported from ECLIPSE to purpose-written software, which simulated the dose distribution delivered to a moving target. Target motion parallel and perpendicular to the MLC motion was investigated for a range of amplitudes (0.5-4.0 cm), periods (1.5-10 s), and MLC speeds (0.1-3.0 cm/s) with target motions modeled as sin. Results were confirmed experimentally by measuring the dose delivered to an ion chamber array in a moving phantom for different MLC sequences. The simulation results were used to identify MLC sequences that kept dose variations within 10% compared to the dose delivered with no motion. The maximum allowable MLC speed, when target motion is parallel to the MLC motion, was found to be a simple function of target period and MLC separation. When the target motion is perpendicular to MLC motion, the maximum allowable MLC speed can be described as a function of MLC separation and the displacement of adjacent MLCs. These guidelines were successfully applied to two-dimensional motion, and a simple program was written to import MLC sequence files and evaluate whether the maximum daily dose discrepancy caused by the interplay effect will be larger than 10%. This software was experimentally evaluated, and found to conservatively predict whether a given MLC sequence could give large daily dose discrepancies.

  3. 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.

  4. 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…

  5. 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

  6. 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

  7. The transcription factor Mlc promotes Vibrio cholerae biofilm formation through repression of phosphotransferase system components.

    PubMed

    Pickering, Bradley S; Lopilato, Jane E; Smith, Daniel R; Watnick, Paula I

    2014-07-01

    The phosphoenol phosphotransferase system (PTS) is a multicomponent signal transduction cascade that regulates diverse aspects of bacterial cellular physiology in response to the availability of high-energy sugars in the environment. Many PTS components are repressed at the transcriptional level when the substrates they transport are not available. In Escherichia coli, the transcription factor Mlc (for makes large colonies) represses transcription of the genes encoding enzyme I (EI), histidine protein (HPr), and the glucose-specific enzyme IIBC (EIIBC(Glc)) in defined media that lack PTS substrates. When glucose is present, the unphosphorylated form of EIIBC(Glc) sequesters Mlc to the cell membrane, preventing its interaction with DNA. Very little is known about Vibrio cholerae Mlc. We found that V. cholerae Mlc activates biofilm formation in LB broth but not in defined medium supplemented with either pyruvate or glucose. Therefore, we questioned whether V. cholerae Mlc functions differently than E. coli Mlc. Here we have shown that, like E. coli Mlc, V. cholerae Mlc represses transcription of PTS components in both defined medium and LB broth and that E. coli Mlc is able to rescue the biofilm defect of a V. cholerae Δmlc mutant. Furthermore, we provide evidence that Mlc indirectly activates transcription of the vps genes by repressing expression of EI. Because activation of the vps genes by Mlc occurs under only a subset of the conditions in which repression of PTS components is observed, we conclude that additional inputs present in LB broth are required for activation of vps gene transcription by Mlc.

  8. 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

  9. An experimental evaluation of the Agility MLC for motion-compensated VMAT delivery

    NASA Astrophysics Data System (ADS)

    Davies, G. A.; Clowes, P.; Bedford, J. L.; Evans, P. M.; Webb, S.; Poludniowski, G.

    2013-07-01

    An algorithm for dynamic multileaf-collimator (dMLC) tracking of a target performing a known a priori, rigid-body motion during volumetric modulated arc therapy (VMAT), has been experimentally validated and applied to investigate the potential of the Agility (Elekta AB, Stockholm, Sweden) multileaf-collimator (MLC) for use in motion-compensated VMAT delivery. For five VMAT patients, dosimetric measurements were performed using the Delta4 radiation detector (ScandiDos, Uppsala, Sweden) and the accuracy of dMLC tracking was evaluated using a gamma-analysis, with threshold levels of 3% for dose and 3 mm for distance-to-agreement. For a motion trajectory with components in two orthogonal directions, the mean gamma-analysis pass rate without tracking was found to be 58.0%, 59.0% and 60.9% and was increased to 89.1%, 88.3% and 93.1% with MLC tracking, for time periods of motion of 4 s, 6 s and 10 s respectively. Simulations were performed to compare the efficiency of the Agility MLC with the MLCi MLC when used for motion-compensated VMAT delivery for the same treatment plans and motion trajectories. Delivery time increases from a static-tumour to dMLC-tracking VMAT delivery were observed in the range 0%-20% for the Agility, and 0%-57% with the MLCi, indicating that the increased leaf speed of the Agility MLC is beneficial for MLC tracking during lung radiotherapy.

  10. Are simple IMRT beams more robust against MLC error? Exploring the impact of MLC errors on planar quality assurance and plan quality for different complexity beams.

    PubMed

    Wang, Jiazhou; Jin, Xiance; Peng, Jiayuan; Xie, Jiang; Chen, Junchao; Hu, Weigang

    2016-01-01

    This study investigated the impact of beam complexities on planar quality assur-ance and plan quality robustness by introducing MLC errors in intensity-modulate radiation therapy. Forty patients' planar quality assurance (QA) plans were enrolled in this study, including 20 dynamic MLC (DMLC) IMRT plans and 20 static MLC (SMLC) IMRT plans. The total beam numbers were 150 and 160 for DMLC and SMLC, respectively. Six different magnitudes of MLC errors were introduced to these beams. Gamma pass rates were calculated by comparing error-free fluence and error-induced fluence. The plan quality variation was acquired by comparing PTV coverage. Eight complexity scores were calculated based on the beam flu-ence and the MLC sequence. The complexity scores include fractal dimension, monitor unit, modulation index, fluence map complexity, weighted average of field area, weighted average of field perimeter, and small aperture ratio (< 5 cm2 and < 50cm2). The Spearman's rank correlation coefficient was calculated to analyze the correlation between these scores and gamma pass rate and plan quality varia-tion. For planar QA, the most significant complexity index was fractal dimension for DMLC (p = -0.40) and weighted segment area for SMLC (p = 0.27) at low magnitude MLC error. For plan quality, the most significant complexity index was weighted segment perimeter for DMLC (p = 0.56) and weighted segment area for SMLC (p= 0.497) at low magnitude MLC error. The sensitivity of planar QA was weakly associated with the field complexity with low magnitude MLC error, but the plan quality robustness was associated with beam complexity. Plans with simple beams were more robust to MLC error.

  11. Reassessing the Annual Pelvic Exam

    MedlinePlus

    ... recommendation released Tuesday, the U.S. Preventive Services Task Force said it couldn't weigh in for or ... pelvic exams based on current evidence. "The Task Force is calling for more research to better understand ...

  12. 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)

  13. An EPID-based system for gantry-resolved MLC quality assurance for VMAT.

    PubMed

    Zwan, Benjamin J; Barnes, Michael P; Fuangord, Todsaporn; Stanton, Cameron J; O'Connor, Daryl J; Keall, Paul J; Greer, Peter B

    2016-01-01

    Multileaf collimator (MLC) positions should be precisely and independently mea-sured as a function of gantry angle as part of a comprehensive quality assurance (QA) program for volumetric-modulated arc therapy (VMAT). It is also ideal that such a QA program has the ability to relate MLC positional accuracy to patient-specific dosimetry in order to determine the clinical significance of any detected MLC errors. In this work we propose a method to verify individual MLC trajectories during VMAT deliveries for use as a routine linear accelerator QA tool. We also extend this method to reconstruct the 3D patient dose in the treatment planning sys-tem based on the measured MLC trajectories and the original DICOM plan file. The method relies on extracting MLC positions from EPID images acquired at 8.41fps during clinical VMAT deliveries. A gantry angle is automatically tagged to each image in order to obtain the MLC trajectories as a function of gantry angle. This analysis was performed for six clinical VMAT plans acquired at monthly intervals for three months. The measured trajectories for each delivery were compared to the MLC positions from the DICOM plan file. The maximum mean error detected was 0.07 mm and a maximum root-mean-square error was 0.8 mm for any leaf of any delivery. The sensitivity of this system was characterized by introducing random and systematic MLC errors into the test plans. It was demonstrated that the system is capable of detecting random and systematic errors on the range of 1-2mm and single leaf calibration errors of 0.5 mm. The methodology developed in the work has potential to be used for efficient routine linear accelerator MLC QA and pretreatment patient-specific QA and has the ability to relate measured MLC positional errors to 3D dosimetric errors within a patient volume.

  14. An EPID-based system for gantry-resolved MLC quality assurance for VMAT.

    PubMed

    Zwan, Benjamin J; Barnes, Michael P; Fuangord, Todsaporn; Stanton, Cameron J; O'Connor, Daryl J; Keall, Paul J; Greer, Peter B

    2016-01-01

    Multileaf collimator (MLC) positions should be precisely and independently mea-sured as a function of gantry angle as part of a comprehensive quality assurance (QA) program for volumetric-modulated arc therapy (VMAT). It is also ideal that such a QA program has the ability to relate MLC positional accuracy to patient-specific dosimetry in order to determine the clinical significance of any detected MLC errors. In this work we propose a method to verify individual MLC trajectories during VMAT deliveries for use as a routine linear accelerator QA tool. We also extend this method to reconstruct the 3D patient dose in the treatment planning sys-tem based on the measured MLC trajectories and the original DICOM plan file. The method relies on extracting MLC positions from EPID images acquired at 8.41fps during clinical VMAT deliveries. A gantry angle is automatically tagged to each image in order to obtain the MLC trajectories as a function of gantry angle. This analysis was performed for six clinical VMAT plans acquired at monthly intervals for three months. The measured trajectories for each delivery were compared to the MLC positions from the DICOM plan file. The maximum mean error detected was 0.07 mm and a maximum root-mean-square error was 0.8 mm for any leaf of any delivery. The sensitivity of this system was characterized by introducing random and systematic MLC errors into the test plans. It was demonstrated that the system is capable of detecting random and systematic errors on the range of 1-2mm and single leaf calibration errors of 0.5 mm. The methodology developed in the work has potential to be used for efficient routine linear accelerator MLC QA and pretreatment patient-specific QA and has the ability to relate measured MLC positional errors to 3D dosimetric errors within a patient volume. PMID:27685132

  15. [MLC positioning checks and calibration with a portal imaging system].

    PubMed

    Schiefer, Hans; Seelentag, Wolf W; Roth, Jakob; Krusche, Bernd

    2008-01-01

    For checking the leaf positions of a MLC (Multi Leaf Collimator) images are acquired with an EPID (Electronic Portal Imaging Device) and then evaluated with a programme (MLC check) developed in-house. During image acquisition a Perspex tray with two metal markers of known position (in the radiation field) is inserted in the satellite tray holder. After determination of the marker positions within the image coordinate system, the image can be transformed to the radiation field coordinate system. This allows the exact determination of the leaf tip positions relative to the radiation field. This evaluation can be applied to images of arbitrary field shapes, provided they were acquired in the same geometry (EPID position, gantry and collimator angles). The entire measurement procedure is based on images in bmp (Windows Bitmap) format, with a 1024 x 1024 matrix and a pixel depth of 24 bit (8 bit per color channel). A suitable marker plate can be manufactured without sophisticated workload; thus the method may be easily and cost effectively adapted at other locations.

  16. 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.…

  17. 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…

  18. 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

  19. 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.

  20. From Exam to Education: The Math Exam/Education Resources

    ERIC Educational Resources Information Center

    Bruni, Carmen; Koch, Christina; Konrad, Bernhard; Lindstrom, Michael; Moyles, Iain; Thompson, Will

    2016-01-01

    The Math Exam/Education Resources (MER) is an open online learning resource hosted at The University of British Columbia (UBC), aimed at providing mathematics education resources for students and instructors at UBC. In this paper, there will be a discussion of the motivation for creating this resource on the MediaWiki platform, key features of the…

  1. 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\

  2. The beta1 subunit of the Na,K-ATPase pump interacts with megalencephalic leucoencephalopathy with subcortical cysts protein 1 (MLC1) in brain astrocytes: new insights into MLC pathogenesis.

    PubMed

    Brignone, Maria S; Lanciotti, Angela; Macioce, Pompeo; Macchia, Gianfranco; Gaetani, Matteo; Aloisi, Francesca; Petrucci, Tamara C; Ambrosini, Elena

    2011-01-01

    Megalencephalic leucoencephalopathy with subcortical cysts (MLC) is a rare congenital leucodystrophy caused by mutations in MLC1, a membrane protein of unknown function. MLC1 expression in astrocyte end-feet contacting blood vessels and meninges, along with brain swelling, fluid cysts and myelin vacuolation observed in MLC patients, suggests a possible role for MLC1 in the regulation of fluid and ion homeostasis and cellular volume changes. To identify MLC1 direct interactors and dissect the molecular pathways in which MLC1 is involved, we used NH2-MLC1 domain as a bait to screen a human brain library in a yeast two-hybrid assay. We identified the β1 subunit of the Na,K-ATPase pump as one of the interacting clones and confirmed it by pull-downs, co-fractionation assays and immunofluorescence stainings in human and rat astrocytes in vitro and in brain tissue. By performing ouabain-affinity chromatography on astrocyte and brain extracts, we isolated MLC1 and the whole Na,K-ATPase enzyme in a multiprotein complex that included Kir4.1, syntrophin and dystrobrevin. Because Na,K-ATPase is involved in intracellular osmotic control and volume regulation, we investigated the effect of hypo-osmotic stress on MLC1/Na,K-ATPase relationship in astrocytes. We found that hypo-osmotic conditions increased MLC1 membrane expression and favoured MLC1/Na,K-ATPase-β1 association. Moreover, hypo-osmosis induced astrocyte swelling and the reversible formation of endosome-derived vacuoles, where the two proteins co-localized. These data suggest that through its interaction with Na,K-ATPase, MLC1 is involved in the control of intracellular osmotic conditions and volume regulation in astrocytes, opening new perspectives for understanding the pathological mechanisms of MLC disease. PMID:20926452

  3. 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…

  4. 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

  5. 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…

  6. 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.

  7. 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.

  8. Impaired coronary microvascular dilation correlates with enhanced vascular smooth muscle MLC phosphorylation in Diabetes

    PubMed Central

    Clements, Richard T; Sodha, Neel R.; Feng, Jun; Boodhwani, Munir; Liu, Yuhong; Mieno, Shigetoshi; Khabbaz, Kamal; Bianchi, Cesario; Sellke, Frank W.

    2011-01-01

    Objective Impaired endothelium-independent vasodilation is a known consequence of type-1 and 2 diabetes, and the mechanism of impaired vasodilation is not well understood. The following study investigated the effects of type-1 and 2 diabetes in endothelial-independent vasodilation associated with coronary vascular smooth muscle (VSM) relaxation and contractile signaling mechanisms. Methods Type-1 diabetes was induced in Yucatan mini-swine via alloxan injection and treated with or without insulin(DM and IDM). Non-diabetic swine served as controls(ND). Expression and/or phosphorylation of determinants of VSM relaxation and contraction signaling were examined in coronary arteries and microvessels. Coronary microvessel relaxation was assessed using sodium nitroprusside(SNP). In addition, SNP-induced vasodilation and myosin light chain (MLC) phosphorylation was determined in coronary microvessels isolated from ND and type-2 diabetic human atrial appendage. Results Diabetic impairment in SNP-induced relaxation was completely normalized by insulin. Soluble guanylate cyclase (sGC) VSM expression decreased in both DM and IDM groups and did not correlate with vasorelaxation. Phosphorylation of MLC and myosin phosphatase increased in the DM group and MLC phosphorylation strongly correlated with impaired VSM relaxation(r=.670, p<0.01). Coronary microvessels from type-2 diabetic human patients exhibited similarly impaired vasodilation and enhanced VSM MLC phosphorylation. Conclusions Impaired vasodilation in type-1 diabetes correlates with enhanced VSM MLC phosphorylation. In addition, enhanced VSM MLC phosphorylation is associated with impaired vasodilation in type 2 diabetes in humans. PMID:19152178

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

    PubMed

    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

    2014-06-01

    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.

  10. 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.

  11. Experimental verification of a Monte Carlo-based MLC simulation model for IMRT dose calculation

    SciTech Connect

    Tyagi, Neelam; Moran, Jean M.; Litzenberg, Dale W.; Bielajew, Alex F.; Fraass, Benedick A.; Chetty, Indrin J.

    2007-02-15

    Inter- and intra-leaf transmission and head scatter can play significant roles in intensity modulated radiation therapy (IMRT)-based treatment deliveries. In order to accurately calculate the dose in the IMRT planning process, it is therefore important that the detailed geometry of the multi-leaf collimator (MLC), in addition to other components in the accelerator treatment head, be accurately modeled. In this paper, we have used the Monte Carlo method (MC) to develop a comprehensive model of the Varian 120 leaf MLC and have compared it against measurements in homogeneous phantom geometries under different IMRT delivery circumstances. We have developed a geometry module within the DPM MC code to simulate the detailed MLC design and the collimating jaws. Tests consisting of leakage, leaf positioning and static MLC shapes were performed to verify the accuracy of transport within the MLC model. The calculations show agreement within 2% in the high dose region for both film and ion-chamber measurements for these static shapes. Clinical IMRT treatment plans for the breast [both segmental MLC (SMLC) and dynamic MLC (DMLC)], prostate (SMLC) and head and neck split fields (SMLC) were also calculated and compared with film measurements. Such a range of cases were chosen to investigate the accuracy of the model as a function of modulation in the beamlet pattern, beamlet width, and field size. The overall agreement is within 2%/2 mm of the film data for all IMRT beams except the head and neck split field, which showed differences up to 5% in the high dose regions. Various sources of uncertainties in these comparisons are discussed.

  12. 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

  13. Optimization of intensity modulated radiotherapy under constraints for static and dynamic MLC delivery.

    PubMed

    Alber, M; Nüsslin, F

    2001-12-01

    Multi-leaf collimators (MLCs) are emerging as the prevalent modality to apply intensity modulated radiotherapy (IMRT). Both the principle and the particular design of MLCs stipulate complex constraints on the practically applicable intensity modulated radiation fields. Most consequentially, the distribution of exposure times across the maximum field outline is either a piecewise constant function in the static mode or a piecewise linear function in the dynamic mode of driving an MLC. In view of clinical utility, the total leaf movement should be minimized, which requires that MLC-related constraints be considered in the dose optimization process. A method is proposed to achieve this for both static MLC fields and dynamic leaf close-in application. The method is an amendment to a generic gradient-based IMRT dose optimization algorithm and solves numerical problems related to the non-convexity of the MLC constraints, which can cause erratic behaviour of a gradient-based algorithm. It employs bistable penalty functions to select preferrable leaf configurations from the configuration space of the MLC, which is limited by specific design features. Together with an 'annealing' escape mechanism from local minima, the algorithm is capable of finding the optimum of an IMRT problem as leaf sequences with minimized leaf travel. In particular, the efficiency of static IMRT can be raised to the levels of unmodulated fields with very few field segments, thereby increasing the utility of IMRT in clinical practice.

  14. PKM2 phosphorylates MLC2 and regulates cytokinesis of tumor cells

    PubMed Central

    Jiang, Yuhui; Wang, Yugang; Wang, Ting; Hawke, David H.; Zheng, Yanhua; Li, Xinjian; Zhou, Qin; Majumder, Sadhan; Bi, Erfei; Liu, David X.; Huang, Suyun; Lu, Zhimin

    2014-01-01

    Pyruvate kinase M2 (PKM2) is expressed at high levels during embryonic development and tumor progression and is important for cell growth. However, it is not known whether it directly controls cell division. Here, we found that Aurora B phosphorylates PKM2, but not PKM1, at T45; this phosphorylation is required for PKM2's localization and interaction with myosin light chain 2 (MLC2) in the contractile ring region of mitotic cells during cytokinesis. PKM2 phosphorylates MLC2 at Y118, which primes the binding of ROCK2 to MLC2 and subsequent ROCK2-dependent MLC2 S15 phosphorylation. PKM2-regulated MLC2 phosphorylation, which is greatly enhanced by EGF stimulation or EGFRvIII, K-Ras G12V, and B-Raf V600E mutant expression, plays a pivotal role in cytokinesis, cell proliferation, and brain tumor development. These findings underscore the instrumental function of PKM2 in oncogenic EGFR-, K-Ras-, and B-Raf-regulated cytokinesis and tumorigenesis. PMID:25412762

  15. The art of a pediatric exam.

    PubMed

    Riley, Debra

    2014-06-15

    This article discusses incorporating "artistry" into a primary care pediatric exam, a technique that considers a child's cognitive developmental stage, previous medical experiences, and the family's general stressors and fears. Benefits of using the artistic exam technique include decreased fear and anxiety for both the child and parent and fewer unnecessary diagnostic tests. The artistic exam has also been shown to improve adherence to pre- and postcare instructions and improved quality outcomes.

  16. The suppression of myosin light chain (MLC) phosphorylation during the response to lipopolysaccharide (LPS): beneficial or detrimental to endothelial barrier?

    PubMed

    Bogatcheva, Natalia V; Zemskova, Marina A; Poirier, Christophe; Mirzapoiazova, Tamara; Kolosova, Irina; Bresnick, Anne R; Verin, Alexander D

    2011-12-01

    Sepsis-induced vascular leakage is a major underlying cause of the respiratory dysfunction seen in severe sepsis. Here, we studied the role of MLC phosphorylation in LPS-induced endothelial hyperpermeability and assessed how the changes in phospho-MLC distribution affect LPS-induced barrier dysfunction. We demonstrated that the changes in human lung microvascular endothelial permeability are preceded by the increase in intracellular calcium level, and increase in MYPT and MLC phosphorylation. Using the siRNA approach, we showed that both LPS-induced barrier dysfunction and MLC phosphorylation are attenuated by the depletion of the smooth muscle isoform of MLC kinase (MLCK) and Rho kinase 2 (ROCK2). Surprisingly, pharmacological inhibition of both ROCK1 and 2 with Y-27632 exacerbated LPS-induced drop in transendothelial resistance, although significantly decreasing MLC phosphorylation level. We next studied the involvement of protein kinase A (PKA)-dependent pathways in LPS-induced barrier dysfunction. We showed that LPS decreased the level of PKA-dependent phosphorylation in endothelial cells; and the pretreatment with forskolin or PKA activator bnz-cAMP counteracted this effect. Forskolin and bnz-cAMP also attenuated LPS-induced increase in MLC phosphorylation level. As we have shown earlier (Bogatcheva et al., 2009), forskolin and bnz-cAMP provide protection from LPS-induced barrier dysfunction. We compared the effects of bnz-cAMP and Y-27632 on phospho-MLC distribution and observed that while bnz-cAMP increased the association of the phospho-MLC signal with the cortical structures, Y-27632 decreased this association. These data indicate that an overall decrease in MLC phosphorylation could be either beneficial or detrimental to endothelial barrier, depending on the intracellular locale of major phospho-MLC changes. PMID:21302311

  17. Phosphorylated Myosin Light Chain 2 (p-MLC2) as a Molecular Marker of Antemortem Coronary Artery Spasm

    PubMed Central

    Li, Liliang; Li, Yuhua; Lin, Junyi; Jiang, Jieqing; He, Meng; Sun, Daming; Zhao, Ziqin; Shen, Yiwen; Xue, Aimin

    2016-01-01

    Background It is not uncommon that only mild coronary artery stenosis is grossly revealed after a system autopsy. While coronary artery spasm (CAS) is the suspected mechanism of these deaths, no specific biomarker has been identified to suggest antemortem CAS. Material/Methods To evaluate the potential of using phosphorylated myosin light chain 2 (p-MLC2) as a diagnostic marker of antemortem CAS, human vascular smooth muscle cells (VSMCs) were cultured and treated with common vasoconstrictors, including prostaglandins F2α (PGF2α), acetylcholine (ACh), and 5-hydroxy tryptamine (5-HT). The p-MLC2 level was examined in the cultured cells using Western blot analysis and in a rat model of spasm provocation tests using immunohistochemistry (IHC). Effects of increased p-MLC2 level on VSMCs contractile activities were assessed in vitro using confocal immunofluorescence assay. Four fatal cases with known antemortem CAS were collected and subject to p-MLC2 detection. Results The p-MLC2 was significantly increased in VSMCs after treatments with vasoconstrictors and in the spasm provocation tests. Myofilament was well-organized and densely stained in VSMCs with high p-MLC2 level, but disarrayed in VSMCs with low p-MLC2 level. Three of the 4 autopsied cases showed strongly positive staining of p-MLC2 at the stenosed coronary segment and the adjacent interstitial small arteries. The fourth case was autopsied at the 6th day after death and showed negative-to-mild positive staining of p-MLC2. Conclusions p-MLC2 might be a useful marker for diagnosis of antemortem CAS. Autopsy should be performed as soon as possible to collect coronary arteries for detection of p-MLC2. PMID:27643564

  18. Phosphorylated Myosin Light Chain 2 (p-MLC2) as a Molecular Marker of Antemortem Coronary Artery Spasm.

    PubMed

    Li, Liliang; Li, Yuhua; Lin, Junyi; Jiang, Jieqing; He, Meng; Sun, Daming; Zhao, Ziqin; Shen, Yiwen; Xue, Aimin

    2016-01-01

    BACKGROUND It is not uncommon that only mild coronary artery stenosis is grossly revealed after a system autopsy. While coronary artery spasm (CAS) is the suspected mechanism of these deaths, no specific biomarker has been identified to suggest antemortem CAS. MATERIAL AND METHODS To evaluate the potential of using phosphorylated myosin light chain 2 (p-MLC2) as a diagnostic marker of antemortem CAS, human vascular smooth muscle cells (VSMCs) were cultured and treated with common vasoconstrictors, including prostaglandins F2α (PGF2α), acetylcholine (ACh), and 5-hydroxy tryptamine (5-HT). The p-MLC2 level was examined in the cultured cells using Western blot analysis and in a rat model of spasm provocation tests using immunohistochemistry (IHC). Effects of increased p-MLC2 level on VSMCs contractile activities were assessed in vitro using confocal immunofluorescence assay. Four fatal cases with known antemortem CAS were collected and subject to p-MLC2 detection. RESULTS The p-MLC2 was significantly increased in VSMCs after treatments with vasoconstrictors and in the spasm provocation tests. Myofilament was well-organized and densely stained in VSMCs with high p-MLC2 level, but disarrayed in VSMCs with low p-MLC2 level. Three of the 4 autopsied cases showed strongly positive staining of p-MLC2 at the stenosed coronary segment and the adjacent interstitial small arteries. The fourth case was autopsied at the 6th day after death and showed negative-to-mild positive staining of p-MLC2. CONCLUSIONS p-MLC2 might be a useful marker for diagnosis of antemortem CAS. Autopsy should be performed as soon as possible to collect coronary arteries for detection of p-MLC2. PMID:27643564

  19. 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

    2015-05-08

    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.

  20. 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

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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…

  6. 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)

  7. 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…

  8. SU-C-BRB-02: Symmetric and Asymmetric MLC Based Lung Shielding and Dose Optimization During Translating Bed TBI

    SciTech Connect

    Ahmed, S; Kakakhel, MB; Ahmed, SBS; Hussain, A

    2015-06-15

    Purpose: The primary aim was to introduce a dose optimization method for translating bed total body irradiation technique that ensures lung shielding dynamically. Symmetric and asymmetric dynamic MLC apertures were employed for this purpose. Methods: The MLC aperture sizes were defined based on the radiological depth values along the divergent ray lines passing through the individual CT slices. Based on these RD values, asymmetrically shaped MLC apertures were defined every 9 mm of the phantom in superior-inferior direction. Individual MLC files were created with MATLAB™ and were imported into Eclipse™ treatment planning system for dose calculations. Lungs can be shielded to an optimum level by reducing the MLC aperture width over the lungs. The process was repeated with symmetrically shaped apertures. Results: Dose-volume histogram (DVH) analysis shows that the asymmetric MLC based technique provides better dose coverage to the body and optimum shielding of the lungs compared to symmetrically shaped beam apertures. Midline dose homogeneity is within ±3% with asymmetric MLC apertures whereas it remains within ±4.5% with symmetric ones (except head region where it drops down to −7%). The substantial over and under dosage of ±5% at tissue interfaces has been reduced to ±2% with asymmetric MLC technique. Lungs dose can be reduced to any desired limit. In this experiment lungs dose was reduced to 80% of the prescribed dose, as was desired. Conclusion: The novel asymmetric MLC based technique assures optimum shielding of OARs (e.g. lungs) and better 3-D dose homogeneity and body-dose coverage in comparison with the symmetric MLC aperture optimization. The authors acknowledge the financial and infrastructural support provided by Pakistan Institute of Engineering & Applied Sciences (PIEAS), Islamabad and Aga Khan University Hospital (AKUH), Karachi during the course of this research project. Authors have no conflict of interest with any national / international

  9. 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

  10. 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.

  11. 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

  12. Analytic IMRT dose calculations utilizing Monte Carlo to predict MLC fluence modulation

    SciTech Connect

    Mihaylov, I.B.; Lerma, F.A.; Wu, Y.; Siebers, J.V.

    2006-04-15

    A hybrid dose-computation method is designed which accurately accounts for multileaf collimator (MLC)-induced intensity modulation in intensity modulated radiation therapy (IMRT) dose calculations. The method employs Monte Carlo (MC) modeling to determine the fluence modulation caused by the delivery of dynamic or multisegmental (step-and-shoot) MLC fields, and a conventional dose-computation algorithm to estimate the delivered dose to a phantom or a patient. Thus, it determines the IMRT fluence prediction accuracy achievable by analytic methods in the limit that the analytic method includes all details of the MLC leaf transport and scatter. The hybrid method is validated and benchmarked by comparison with in-phantom film dose measurements, as well as dose calculations from two in-house, and two commercial treatment planning system analytic fluence estimation methods. All computation methods utilize the same dose algorithm to calculate dose to a phantom, varying only in the estimation of the MLC modulation of the incident photon energy fluence. Gamma analysis, with respect to measured two-dimensional (2D) dose planes, is used to benchmark each algorithm's performance. The analyzed fields include static and dynamic test patterns, as well as fields from ten DMLC IMRT treatment plans (79 fields) and five SMLC treatment plans (29 fields). The test fields (fully closed MLC, picket fence, sliding windows of different size, and leaf-tip profiles) cover the extremes of MLC usage during IMRT, while the patient fields represent realistic clinical conditions. Of the methods tested, the hybrid method most accurately reproduces measurements. For the hybrid method, 79 of 79 DMLC field calculations have {gamma}{<=}1 (3%/3 mm) for more than 95% of the points (per field) while for SMLC fields, 27 of 29 pass the same criteria. The analytic energy fluence estimation methods show inferior pass rates, with 76 of 79 DMLC and 24 of 29 SMLC fields having more than 95% of the test points

  13. 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

  14. NOTE: Analysis of the measurement precision of an amorphous silicon EPID used for MLC leaf position quality control and the long-term calibration stability of an optically controlled MLC

    NASA Astrophysics Data System (ADS)

    Budgell, G. J.; Clarke, M. F.

    2008-08-01

    Electronic portal imaging devices (EPIDs) have been shown to be suitable for multileaf collimator (MLC) leaf positioning quality control (QC). In our centre, a continuous dataset is available of 2 years of film measurements followed by 3 years of EPID measurements on five MLC-equipped linear accelerators of identical head design. The aim of this work was to analyse this unique dataset in order to determine the relative precision of film and EPID for MLC leaf positioning measurements and to determine the long-term stability of the MLC calibration. The QC dataset was examined and periods without MLC adjustments that contained at least four successive collimator position measurements (a minimum of 6 months) were identified. By calculating the standard deviations (SD) of these results, the reproducibility of the measurements can be determined. Comparison of the film and EPID results enables their relative measurement precision to be assessed; on average film gave an SD of 0.52 mm compared to 0.13 mm for EPIDs. The MLC and conventional collimator results were compared to assess MLC calibration stability; on average, for EPID measurements, the MLC gave an SD of 0.12 mm compared to 0.14 mm for a conventional collimator. The long-term relative individual leaf positions were compared and found to vary between 0.07 and 0.15 mm implying that they are stable over long time periods. These results suggest that the calibration of an optically controlled MLC is inherently very stable between disturbances to the optical system which normally occur on service days.

  15. 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 Winston–Lutz 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 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° 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

  16. 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.

  17. Expedition 35/36 Final Exams

    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...

  18. Expedition 32 Final Soyuz Qualification Exams

    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. 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

  20. 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

  1. 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…

  2. 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…

  3. Motion management during IMAT treatment of mobile lung tumors—A comparison of MLC tracking and gated delivery

    PubMed Central

    Falk, Marianne; Pommer, Tobias; Keall, Paul; Korreman, Stine; Persson, Gitte; Poulsen, Per; Munck af Rosenschöld, Per

    2014-01-01

    Purpose: To compare real-time dynamic multileaf collimator (MLC) tracking, respiratory amplitude and phase gating, and no compensation for intrafraction motion management during intensity modulated arc therapy (IMAT). Methods: Motion management with MLC tracking and gating was evaluated for four lung cancer patients. The IMAT plans were delivered to a dosimetric phantom mounted onto a 3D motion phantom performing patient-specific lung tumor motion. The MLC tracking system was guided by an optical system that used stereoscopic infrared (IR) cameras and five spherical reflecting markers attached to the dosimetric phantom. The gated delivery used a duty cycle of 35% and collected position data using an IR camera and two reflecting markers attached to a marker block. Results: The average gamma index failure rate (2% and 2 mm criteria) was <0.01% with amplitude gating for all patients, and <0.1% with phase gating and <3.7% with MLC tracking for three of the four patients. One of the patients had an average failure rate of 15.1% with phase gating and 18.3% with MLC tracking. With no motion compensation, the average gamma index failure rate ranged from 7.1% to 46.9% for the different patients. Evaluation of the dosimetric error contributions showed that the gated delivery mainly had errors in target localization, while MLC tracking also had contributions from MLC leaf fitting and leaf adjustment. The average treatment time was about three times longer with gating compared to delivery with MLC tracking (that did not prolong the treatment time) or no motion compensation. For two of the patients, the different motion compensation techniques allowed for approximately the same margin reduction but for two of the patients, gating enabled a larger reduction of the margins than MLC tracking. Conclusions: Both gating and MLC tracking reduced the effects of the target movements, although the gated delivery showed a better dosimetric accuracy and enabled a larger reduction of the

  4. 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.

  5. 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)

  6. 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.

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Exhausting treadmill running causes dephosphorylation of sMLC2 and reduced level of myofilament MLCK2 in slow twitch rat soleus muscle.

    PubMed

    Hortemo, Kristin Halvorsen; Aronsen, Jan Magnus; Lunde, Ida G; Sjaastad, Ivar; Lunde, Per Kristian; Sejersted, Ole M

    2015-02-01

    Myosin light chain 2 (MLC2) is a small protein in the myosin complex, regulating muscle contractile function by modulating Ca(2+) sensitivity of myofilaments. MLC2 can be modified by phosphorylation and O-GlcNAcylation, two reversible and dynamic posttranslational modifications. The slow isoform of MLC2 (sMLC2) is dephosphorylated in soleus muscle during in situ loaded shortening contractions, which correlates with reduction in shortening capacity. Here, we hypothesize that exhausting in vivo treadmill running induces dephosphorylation of MLC2 in slow twitch soleus, but not in fast twitch EDL muscle, and that there are reciprocal changes in MLC2 O-GlcNAcylation. At rest, both phosphorylation and O-GlcNAcylation of MLC2 were lower in slow than fast twitch muscles. One bout of exhausting treadmill running induced dephosphorylation of sMLC2 in soleus, paralleled by reduced levels of the kinase MLCK2 associated to myofilaments, suggesting that the acute reduction in phosphorylation is mediated by dissociation of MLCK2 from myofilaments. O-GlcNAcylation of MLC2 did not change significantly, and seems of limited importance in the regulation of MLC2 phosphorylation during in vivo running. After 6 weeks of treadmill running, the dephosphorylation of sMLC2 persisted in soleus along with reduction in MLCK2 both in myofilament- and total protein fraction. In EDL on the contrary, phosphorylation of MLC2 was not altered after one exercise bout or after 6 weeks of treadmill running. Thus, in contrast to fast twitch muscle, MLC2 dephosphorylation occurs in slow twitch muscle during in vivo exercise and may be linked to reduced myofilament-associated MLCK2 and reduced shortening capacity.

  9. 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.

  10. IMRT treatment planning on 4D geometries for the era of dynamic MLC tracking.

    PubMed

    Suh, Yelin; Murray, Walter; Keall, Paul J

    2014-12-01

    The problem addressed here was to obtain optimal and deliverable dynamic multileaf collimator (MLC) leaf sequences from four-dimensional (4D) geometries for dynamic MLC tracking delivery. The envisaged scenario was where respiratory phase and position information of the target was available during treatment, from which the optimal treatment plan could be further adapted in real time. A tool for 4D treatment plan optimization was developed that integrates a commercially available treatment planning system and a general-purpose optimization system. The 4D planning method was applied to the 4D computed tomography planning scans of three lung cancer patients. The optimization variables were MLC leaf positions as a function of monitor units and respiratory phase. The objective function was the deformable dose-summed 4D treatment plan score. MLC leaf motion was constrained by the maximum leaf velocity between control points in terms of monitor units for tumor motion parallel to the leaf travel direction and between phases for tumor motion parallel to the leaf travel direction. For comparison and a starting point for the 4D optimization, three-dimensional (3D) optimization was performed on each of the phases. The output of the 4D IMRT planning process is a leaf sequence which is a function of both monitor unit and phase, which can be delivered to a patient whose breathing may vary between the imaging and treatment sessions. The 4D treatment plan score improved during 4D optimization by 34%, 4%, and 50% for Patients A, B, and C, respectively, indicating 4D optimization generated a better 4D treatment plan than the deformable sum of individually optimized phase plans. The dose-volume histograms for each phase remained similar, indicating robustness of the 4D treatment plan to respiratory variations expected during treatment delivery. In summary, 4D optimization for respiratory phase-dependent treatment planning with dynamic MLC motion tracking improved the 4D treatment plan

  11. 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.

  12. 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,…

  13. 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,…

  14. 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…

  15. 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…

  16. 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…

  17. 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. ...

  18. Determinants of Student Attitudes toward Team Exams

    ERIC Educational Resources Information Center

    Reinig, Bruce A.; Horowitz, Ira; Whittenburg, Gene

    2014-01-01

    We examine how student attitudes toward their group, learning method, and perceived development of professional skills are initially shaped and subsequently evolve through multiple uses of team exams. Using a Tobit regression model to analyse a sequence of 10 team quizzes given in a graduate-level tax accounting course, we show that there is an…

  19. 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

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

    PubMed

    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

  1. 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

  2. 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

  3. SU-E-J-67: Evaluation of Adaptive MLC Morphing for Online Correction of Prostate Cancer Radiotherapy

    SciTech Connect

    Sandhu, R; Qin, A; Yan, D

    2015-06-15

    Purpose: Online adaptive MLC morphing is desirable over translational couch shifts to accommodate target position as well as anatomic changes. A reliable method of adaptive MLC segment to target during prostate cancer IMRT treatment is proposed and evaluated by comparison with daily online-image guidance (IGRT) correction and online-IMRT planning. Methods: The MLC adaptive algorithm involves following steps; move the MLC segments according to target translational shifts, and then morph the segment shape to maintain the spatial relationship between the planning-target contour and MLC segment. Efficacy of this method was evaluated retrospectively using daily-CBCT images on seven prostate patients treated with seven-beam IMRT treatment to deliver 64Gy in 20 fractions. Daily modification was simulated with three approaches; daily-IGRT correction based on implanted radio-markers, adaptive MLC morphing, and online-IMRT planning, with no-residual variation. The selected dosimetric endpoints and nEUD (normalized equivalent uniform dose to online-IMRT planning) of each organ of interest were determined for evaluation and comparison. Results: For target(prostate), bladder and rectal-wall, the mean±sd of nEUD were 97.6%+3.2%, 103.9%±4.9% and 97.4%±1.1% for daily-IGRT correction; and 100.2%+0.2%, 108.9%±5.1% and 99.8%±1.2% for adaptive MLC morphing, respectively. For daily-IGRT correction, adaptive MLC morphing and online-IMRT planning, target D99 was <95% of the prescription dose in 30%, 0% and 0% of 140 fractions, respectively. For the rectal-wall, D5 exceeded 105% of the planned-D5 in 2.8%, 11.4% and 0% of 140 fractions, respectively. For the bladder, Dmax exceeded 105% of the planned-D5 in 2.8%, 5.6% and 0% of 140 fractions, respectively. D30 of bladder and rectal-wall were well within the planned-D30 for all three approaches. Conclusion: The proposed method of adaptive MLC morphing can be beneficial for the prostate patient population with large deformation and

  4. 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.

  5. Megalencephalic leukoencephalopathy with cysts in twelve Egyptian patients: novel mutations in MLC1 and HEPACAM and a founder effect.

    PubMed

    Abdel-Salam, Ghada M H; Abdel-Hamid, Mohamed S; Ismail, Samira I; Hosny, Heba; Omar, Tarek; Effat, Laila; Aglan, Mona S; Temtamy, Samia A; Zaki, Maha S

    2016-10-01

    Two genes causing megalencephalic leukoencephalopathy with subcortical cysts (MLC) have been discovered so far. Here, we identified MLC1 and HEPACAM mutations in ten and two patients, respectively. The molecular results included an unreported inframe duplication mutation (c.929_930dupCTGCTG; p.L309dup) of MLC1 and a novel missense mutation c.293G>A (p.R98H) of HEPACAM. Further, the previously reported missense (c.278C>T; p.S93L) and the deletion/insertion (c.908_918delinsGCA; p.V303Gfs*96) were found in one and 8 patients (75 %), respectively. The 8 patients carrying the p.V303Gfs*96 shared a similar haplotype suggesting a founder effect. All mutations were in the homozygous state proving the autosomal recessive mode of inheritance. The core phenotype of macrocephaly, subcortical cysts and white matter appeared homogeneous although the patients differed in the onset, clinical course, disease severity and brain imaging findings. Our study expands the spectrum of mutations in MLC1 and HEPACAM and supports the genetic and clinical heterogeneity. Further, It confirms c.908_918delinsGCA (p.V303Gfs*96) as a founder mutation among Egyptian patients. This finding will contribute to provide targeted testing for this mutation in MLC patients in our population. PMID:27389245

  6. Effectiveness and Safety of MLC601 in the Treatment of Mild to Moderate Alzheimer's Disease: A Multicenter, Randomized Controlled Trial

    PubMed Central

    Pakdaman, Hossein; Harandi, Ali Amini; Hatamian, Hamidreza; Tabatabae, Mojgan; Delavar Kasmaei, Hosein; Ghassemi, Amirhossein; Gharagozli, Koroush; Ashrafi, Farzad; Emami Naeini, Pardis; Tavakolian, Mehrnaz; Shahin, Darush

    2015-01-01

    Background MLC601 is a possible modulator of amyloid precursor protein processing, and in a clinical trial study MLC601 showed some effectiveness in cognitive function in Alzheimer's disease (AD) patients. We aimed to evaluate the effectiveness and safety of MLC601 in the treatment of mild to moderate AD as compared to 3 approved cholinesterase inhibitors (ChEIs) including donepezil, rivastigmine and galantamine. Methods In a multicenter, nonblinded, randomized controlled trial, 264 volunteers with AD were randomly divided into 4 groups of 66; groups 1, 2, 3 and 4 received donepezil, rivastigmine, MLC601 and galantamine, respectively. Subjects underwent a clinical diagnostic interview and a cognitive/functional battery including the Mini-Mental State Examination (MMSE) and Alzheimer's Disease Assessment Scale – Cognitive subscale (ADAS-Cog). Patients were visited every 4 months, and the score of cognition was recorded by the neurologists. Results There were no significant differences in age, sex, marital status and baseline score of cognition among the 4 groups. In total, 39 patients (14.7%) left the study. Trend of cognition changes based on the modifications over the time for MMSE and ADAS-cog scores did not differ significantly among groups (p = 0.92 for MMSE and p = 0.87 for ADAS-Cog). Conclusion MLC601 showed a promising safety profile and also efficacy compared to 3 FDA-approved ChEIs. PMID:25873931

  7. Dosimetric and mechanical characteristics of a commercial dynamic {mu}MLC used in SRS

    SciTech Connect

    Galal, Mohamed M.; Keogh, Sinead; Khalil, Sultan

    2011-07-15

    Purpose: The aim of this work is to carry out mechanical and dosimetric assessments on a commercial dynamic micromulti leaf collimator system to be used for stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT). Mechanical parameters such as leaf position accuracy with different gantry angles and leaf position reproducibility were measured. Also dosimetric measurements of the interleaf leakage, intraleaf transmission, penumbra width, and light field alignment were carried out. Furthermore, measurements of output factors (S{sub cp}) and in-air factors (S{sub c}) for the {mu}MLC system will be reported. Methods: EBT2 films were used to assess the leaf position error with gantry angle and after stress test, penumbra width and light field alignment. Leaf leakage was quantified using both EBT2 film and a pinpoint ion chamber. With regard to output factors, the pinpoint chamber was placed in a water phantom at 10 cm depth and 100 cm SSD. For in-air output factor measurements, 0.2 cm of brass was placed above the photon diode as build-up. Results: Measurements of mechanical parameters gave values of 0.05 cm (SD 0.035) for the average leaf position accuracy for different gantry angles and after stress test. Dosimetric measurements, yielded values of 0.22 {+-} 0.01 and 0.24 {+-} 0.01 cm, respectively, for side and head leaf penumbras. Also, average leaf abutting, leakage and transmission were found to be 0.65, 0.91, and 0.20%, respectively. Conclusions: (a) The add-on {mu}MLC system in combination with our LINAC has been commissioned to be used for clinical purposes and showed good agreement with published results for different {mu}MLC types. (b) This work has lead to the recommendation that leaves should be recalibrated after ten static beams or after each dynamic arc.

  8. 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.

  9. 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.

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

    PubMed Central

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

    2012-01-01

    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. PMID:22894437

  11. 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.

  12. Comparative Analysis of Different Measurement Techniques for MLC Characterization: Preliminary Results

    SciTech Connect

    Larraga-Gutierrez, J. M.; Ballesteros-Zebadua, P.; Garcia-Garduno, O. A.; Martinez-Davalos, A.; Rodriguez-Villafuerte, M.; Moreno-Jimenez, S.; Celis, M. A.

    2008-08-11

    Radiation transmission, leakage and beam penumbra are essential dosimetric parameters related to the commissioning of a multileaf collimation system. This work shows a comparative analysis of commonly used film detectors: X-OMAT V2 and EDR2 radiographic films, and GafChromic EBT registered radiochromic film. The results show that X-OMAT over-estimates radiation leakage and 80-20% beam penumbra. However, according to the reference values reported by the manufacturer for these dosimetric parameters, all three films are adequate for MLC dosimetric characterization, but special care must be taken when X-OMAT V2 film is used due to its low energy photon dependence.

  13. Use of an amorphous silicon EPID for measuring MLC calibration at varying gantry angle

    NASA Astrophysics Data System (ADS)

    Clarke, M. F.; Budgell, G. J.

    2008-01-01

    Amorphous silicon electronic portal imaging devices (EPIDs) are used to perform routine quality control (QC) checks on the multileaf collimators (MLCs) at this centre. Presently, these checks are performed at gantry angle 0° and are considered to be valid for all other angles. Since therapeutic procedures regularly require the delivery of MLC-defined fields to the patient at a wide range of gantry angles, the accuracy of the QC checks at other gantry angles has been investigated. When the gantry is rotated to angles other than 0° it was found that the apparent pixel size measured using the EPID varies up to a maximum value of 0.0015 mm per pixel due to a sag in the EPID of up to 9.2 mm. A correction factor was determined using two independent methods at a range of gantry angles between 0° and 360°. The EPID was used to measure field sizes (defined by both x-jaws and MLC) at a range of gantry angles and, after this correction had been applied, any residual gravitational sag was studied. It was found that, when fields are defined by the x-jaws and y-back-up jaws, no errors of greater than 0.5 mm were measured and that these errors were no worse when the MLC was used. It was therefore concluded that, provided the correction is applied, measurements of the field size are, in practical terms, unaffected by gantry angle. Experiments were also performed to study how the reproducibility of individual leaves is affected by gantry angle. Measurements of the relative position of each individual leaf (minor offsets) were performed at a range of gantry angles and repeated three times. The position reproducibility was defined by the RMS error in the position of each leaf and this was found to be 0.24 mm and 0.21 mm for the two leaf banks at a gantry angle of 0°. When measurements were performed at a range of gantry angles, these reproducibility values remained within 0.09 mm and 0.11 mm. It was therefore concluded that the calibration of the Elekta MLC is stable at all

  14. Characterization of megavoltage electron beams delivered through a photon multi-leaf collimator (pMLC)

    NASA Astrophysics Data System (ADS)

    du Plessis, F. C. P.; Leal, A.; Stathakis, S.; Xiong, W.; Ma, C.-M.

    2006-04-01

    A study is presented that characterizes megavoltage electron beams delivered through an existing double-focused photon multi-leaf collimator (pMLC) using film measurements in a solid water phantom. Machine output stability and linearity were evaluated as well as the effect of source-to-surface distance (SSD) and field size on the penumbra for electron energies between 6 and 18 MeV over an SSD range of 60-100 cm. Penumbra variations as a function of field size, depth of measurement and the influence of the jaws were also studied. Field abutment, field flatness and target coverage for segmented beams were also addressed. The measured field size for electrons transported through the pMLC was the same as that for an x-ray beam up to SSDs of 70 cm. At larger SSD, the lower energy electron fields deviated from the projected field. Penumbra data indicated that 60 cm SSD was the most favourable treatment distance. Backprojection of P20-80 penumbra data yielded a virtual source position located at 98.9 cm from the surface for 18 MeV electrons. For 6 MeV electrons, the virtual source position was at a distance of 82.6 cm. Penumbra values were smaller for small beam slits and reached a near-constant value for field widths larger than 5 cm. The influence of the jaws had a small effect on the penumbra. The R90 values ranged from 1.4 to 4.8 cm between 6 and 21 MeV as measured at 60 cm SSD for a 9 × 9 cm2 field. Uniformity and penumbra improvement could be demonstrated using weighted abutted fields especially useful for small segments. No detectable electron leakage through the pMLC was observed. Bremsstrahlung measurements taken at 60 cm SSD for a 9 × 9 cm2 field as shaped by the pMLC compared within 1% to bremsstrahlung measurements taken at 100 cm SSD for a 10 × 10 cm2 electron applicator field at 100 cm SSD.

  15. Dosimetric comparison between cone/Iris-based and InCise MLC-based CyberKnife plans for single and multiple brain metastases.

    PubMed

    Jang, Si Young; Lalonde, Ron; Ozhasoglu, Cihat; Burton, Steven; Heron, Dwight; Huq, M Saiful

    2016-01-01

    We performed an evaluation of the CyberKnife InCise MLC by comparing plan qualities for single and multiple brain lesions generated using the first version of InCise MLC, fixed cone, and Iris collimators. We also investigated differences in delivery efficiency among the three collimators. Twenty-four patients with single or multiple brain mets treated previously in our clinic on a CyberKnife M6 using cone/Iris collimators were selected for this study. Treatment plans were generated for all lesions using the InCise MLC. Number of monitor units, delivery time, target coverage, conformity index, and dose falloff were compared between MLC- and clinical cone/Iris-based plans. Statistical analysis was performed using the non-parametric Wilcoxon-Mann-Whitney signed-rank test. The planning accuracy of the MLC-based plans was validated using chamber and film measurements. The InCise MLC-based plans achieved mean dose and target coverage comparable to the cone/Iris-based plans. Although the conformity indices of the MLC-based plans were slightly higher than those of the cone/Iris-based plans, beam delivery time for the MLC-based plans was shorter by 30% ~ 40%. For smaller targets or cases with OARs located close to or abutting target volumes, MLC-based plans provided inferior dose conformity compared to cone/Iris-based plans. The QA results of MLC-based plans were within 5% absolute dose difference with over 90% gamma passing rate using 2%/2 mm gamma criteria. The first version of InCise MLC could be a useful delivery modality, especially for clinical situations for which delivery time is a limiting factor or for multitarget cases. PMID:27685124

  16. 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…

  17. Effect of Paper Color and Question Order on Exam Performance

    ERIC Educational Resources Information Center

    Tal, Ilanit R.; Akers, Katherine G.; Hodge, Gordon K.

    2008-01-01

    To deter cheating, teachers commonly use exams printed on differently colored paper or with varied question orders. Previous studies, however, reported that paper color and question order affect exam performance and suggested that teachers should adjust students' scores accordingly and discontinue the use of alternate exam forms. We conducted 2…

  18. Evaluating Multiple-Choice Exams in Large Introductory Physics Courses

    ERIC Educational Resources Information Center

    Scott, Michael; Stelzer, Tim; Gladding, Gary

    2006-01-01

    The reliability and validity of professionally written multiple-choice exams have been extensively studied for exams such as the SAT, graduate record examination, and the force concept inventory. Much of the success of these multiple-choice exams is attributed to the careful construction of each question, as well as each response. In this study,…

  19. 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…

  20. Infant oral exam and first dental home.

    PubMed

    Viswanathan, Kavitha

    2010-11-01

    The purpose of this article is to familiarize general practitioners with the components of a dental home including an infant oral exam, and to the First Dental Home initiative, which is unique to the State of Texas. This article encourages the general practitioners to actively participate in providing care for young children under the age of 3. Components of an infant oral examination are described here with emphasis on knee-to-knee or lap exam, caries risk assessment, preventive treatment, age-appropriate anticipatory guidance, and parent education. The First Dental Home is uniquely designed to help pediatric clients 6 months through 35 months of age to establish a dental home. The objectives, goal and components of FDH are discussed in detail.

  1. New technologies to manage exam anxiety.

    PubMed

    Grassi, Alessandra; Gaggioli, Andrea; Riva, Giuseppe

    2011-01-01

    A Stress Inoculation Training-based protocol tested if multimedia audio-video content induced emotional changes and reduced exam anxiety in university students. Seventy-five participants took part in six experimental sessions consisting of viewing multimedia content and performing relaxation exercises. Participants were randomly assigned to five experimental groups: 1) audio and video narrative on mobile phone (UMTS); 2) audio and video narrative on DVD (DVD), 3) audio narrative on MP3 player (M3), 4) audio narrative on CD (CD), 5) control group (CTRL). Results showed that audio/video content induced a significant reduction in exam anxiety and an increase of relaxation in students, compared to the audio-only contents. PMID:21685642

  2. 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

  3. Direct and Indirect Effects of Completion versus Accuracy Contingencies on Practice-Exam and Actual-Exam Performance

    ERIC Educational Resources Information Center

    Oliver, Renee; Williams, Robert L.

    2005-01-01

    Students in four sections of an undergraduate educational course (two large and two small sections) took out-of-class practice exams prior to actual exams for each of five course units. Each course unit consisted of five class sessions focusing on a specific developmental theme. Some sections received practice-exam credit based on the number of…

  4. 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.

  5. 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.

  6. DEK Depletion Negatively Regulates Rho/ROCK/MLC Pathway in Non–Small Cell Lung Cancer

    PubMed Central

    Wang, Junying; Sun, Limei; Yang, Mingyue; Luo, Wenting; Gao, Ying; Liu, Zihui; Wang, Enhua

    2013-01-01

    The human DEK proto-oncogene is a nuclear protein with suspected roles in human carcinogenesis. DEK appears to function in several nuclear processes, including transcriptional regulation and modulation of chromatin structure. To investigate the clinicopathological significance of DEK in patients with non–small cell lung cancer (NSCLC), we analyzed DEK immunohistochemistry in 112 NSCLC cases. The results showed that DEK was overexpressed mainly in the nuclear compartment of tumor cells. In squamous cell carcinoma, DEK-positive expression occurred in 47.9% (23/48) of cases, and in lung adenocarcinoma, DEK-positive expression occurred in 67.2% (43/64) of cases and correlated with differentiation, p-TNM stage, and nodal status. Moreover, in lung adenocarcinoma, DEK expression was significantly higher compared with DEK expression in squamous cell carcinoma. Kaplan-Meier analysis showed that patients with low DEK expression had higher overall survival compared with patients with high DEK expression. Depleting DEK expression inhibited cellular proliferation and migration. Furthermore, in DEK-depleted NSCLC cells, we found that RhoA expression was markedly reduced; in conjunction, active RhoA-GTP levels and the downstream effector phosphorylated MLC2 were also reduced. Taken together, DEK depletion inhibited cellular migration in lung cancer cell lines possibly through inactivation of the RhoA/ROCK/MLC signal transduction pathway. PMID:23571382

  7. 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.

  8. 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.

  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. 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

  11. 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

  12. 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.

  13. 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

  14. 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.

  15. 76 FR 4375 - In the Matter of Certain MLC Flash Memory Devices and Products Containing Same; Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-25

    ...''). 74 FR 43723-4 (August 27, 2009). The complaint, as amended and supplemented, alleges violations of... COMMISSION In the Matter of Certain MLC Flash Memory Devices and Products Containing Same; Notice of... flash memory devices and products containing same by reason of infringement of certain claims of...

  16. Cerebral correlates of cognitive reserve.

    PubMed

    Whalley, Lawrence J; Staff, Roger T; Fox, Helen C; Murray, Alison D

    2016-01-30

    Cognitive reserve is a hypothetical concept introduced to explain discrepancies between severity of clinical dementia syndromes and the extent of dementia pathology. We examined cognitive reserve in a research programme that followed up a non-clinical sample born in 1921 or 1936 and IQ-tested age 11 years in 1932 or 1947. Structural MRI exams were acquired in about 50% of the sample from whom a subsample were recruited into an additional fMRI study. Here, we summarise findings from seven inter-related studies. These support an understanding of cognitive reserve as a balance between positive life course activity-driven experiences and the negative effects of brain pathologies including cerebrovascular disease and total and regional brain volume loss. Hypothesised structural equation models illustrate the relative causal effects of these positive and negative contributions. Cognitive reserve is considered in the context of choice of interventions to prevent dementia and the opposing effects of cerebrovascular disease and Alzheimer like brain appearances.

  17. 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

  18. 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.

  19. 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…

  20. 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.

  1. 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

  2. Pediatric Rectal Exam: Why, When, and How.

    PubMed

    Orenstein, Susan R; Wald, Arnold

    2016-01-01

    The digital rectal examination (DRE) is performed in children less often than is indicated. Indications for the pediatric DRE include diarrhea, constipation, fecal incontinence, abdominal pain, gastrointestinal bleeding, and anemia. Less well-recognized indications may include abdominal mass, urinary symptoms, neurologic symptoms, urogenital or gynecologic symptoms, and anemia. Indeed, we believe that it should be considered part of a complete physical examination in children presenting with many different complaints. Physicians avoid this part of the physical examination in both children and adults for a number of reasons: discomfort on the part of the health care provider; belief that no useful information will be provided; lack of adequate training and experience in the performance of the DRE; conviction that planned "orders" or testing can obviate the need for the DRE; worry about "assaulting" a patient, particularly one who is small, young, and subordinate; anticipation that the exam will be refused by patient or parent; and concern regarding the time involved in the exam. The rationale and clinical utility of the DRE will be summarized in this article. In addition, the components of a complete pediatric DRE, along with suggestions for efficiently obtaining the child's consent and cooperation, will be presented. PMID:26739462

  3. 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

  4. 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

  5. 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

    2016-03-08

    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

  6. 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

  7. 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…

  8. Does the Answer Order Matter on Multiple-Choice Exams?

    ERIC Educational Resources Information Center

    Tellinghuisen, Joel; Sulikowski, Michelle M.

    2008-01-01

    Surprising version-dependent differences are noted in student performance on certain questions in a standardized general chemistry exam. The exam in question has two versions, on which both questions and answers are ordered differently. For the questions suspected of answer-order bias, the performance is better in ten of twelve cases when students…

  9. 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.

  10. Crib Sheets and Exam Performance in a Data Structures Course

    ERIC Educational Resources Information Center

    Hamouda, Sally; Shaffer, Clifford A.

    2016-01-01

    In this paper, we study the relationship between the use of "crib sheets" or "cheat sheets" and performance on in-class exams. Our extensive survey of the existing literature shows that it is not decisive on the questions of when or whether crib sheets actually help students to either perform better on an exam or better learn…

  11. Anxiety and Piano Exams: Turkish Prospective Music Teachers' Experiences

    ERIC Educational Resources Information Center

    Güven, Elif

    2016-01-01

    The purpose of this study is to determine the test anxiety levels of prospective music teachers and their opinions regarding anxiety in piano exams. Test Anxiety Inventory (TAI) and semi-structured interviews were used to meet the purpose. Interviews were conducted with students prior to and after the piano exam. As a result of the study it was…

  12. Authorized Crib Cards Do Not Improve Exam Performance

    ERIC Educational Resources Information Center

    Dickson, K. Laurie; Miller, Michelle D.

    2005-01-01

    We experimentally investigated the effect of authorized crib cards on undergraduates' multiple-choice exam performance for lower order and higher order questions and on anxiety levels in an upper division child and adolescent development course. Students (N =54) in 2 sections could use crib cards during 2 of the 4 exams. Despite student…

  13. 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…

  14. Prior-to-Exam: What Activities Enhance Performance?

    ERIC Educational Resources Information Center

    Rhoads, C. J.; Healy, Therese

    2013-01-01

    Can instructors impact their student performance by recommending an activity just prior to taking an exam? In this study, college students were randomly assigned to one of three treatment groups (study, exercise, or meditation) or a control group. Each group was given two different types of tests; a traditional concept exam, and a non-traditional…

  15. 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,…

  16. 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'…

  17. 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…

  18. 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…

  19. 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…

  20. A Laboratory Practical Exam for High School Chemistry

    ERIC Educational Resources Information Center

    Rhodes, Michelle M.

    2010-01-01

    A station-based laboratory practical exam for first-year high school chemistry students is described. Students move individually through six stations meant to authentically assess both basic lab skills and problem-solving skills utilized throughout the year. The exam can be completed in an approximately 85 min lab period and can be easily adapted…

  1. A Molecular Dynamics Study and Free Energy Analysis of Complexes between the Mlc1p Protein and Two IQ Motif Peptides

    PubMed Central

    Ganoth, Assaf; Friedman, Ran; Nachliel, Esther; Gutman, Menachem

    2006-01-01

    The Mlc1p protein from the budding yeast Saccharomyces cerevisiae is a Calmodulin-like protein, which interacts with IQ-motif peptides located at the yeast's myosin neck. In this study, we report a molecular dynamics study of the Mlc1p-IQ2 protein-peptide complex, starting with its crystal structure, and investigate its dynamics in an aqueous solution. The results are compared with those obtained by a previous study, where we followed the solution structure of the Mlc1p-IQ4 protein-peptide complex by molecular dynamics simulations. After the simulations, we performed an interaction free-energy analysis using the molecular mechanics Poisson-Boltzmann surface area approach. Based on the dynamics of the Mlc1p-IQ protein-peptide complexes, the structure of the light-chain-binding domain of myosin V from the yeast S. cerevisiae is discussed. PMID:16844751

  2. AFFORDABLE MULTI-LAYER CERAMIC (MLC) MANUFACTURING FOR POWER SYSTEMS (AMPS)

    SciTech Connect

    E.A. Barringer, Ph.D.

    2002-11-27

    McDermott Technology, Inc. (MTI) is attempting to develop high-performance, cost-competitive solid oxide fuel cell (SOFC) power systems. Recognizing the challenges and limitations facing the development of SOFC stacks comprised of electrode-supported cells and metallic interconnects, McDermott Technology, Inc. (MTI) has chosen to pursue an alternate path to commercialization. MTI is developing a multi-layer, co-fired, planar SOFC stack that will provide superior performance and reliability at reduced costs relative to competing designs. The MTI approach combines state-of-the-art SOFC materials with the manufacturing technology and infrastructure established for multi-layer ceramic (MLC) packages for the microelectronics industry. The rationale for using MLC packaging technology is that high quality, low-cost manufacturing has been demonstrated at high volumes. With the proper selection of SOFC materials, implementation of MLC fabrication methods offers unique designs for stacks (cells and interconnects) that are not possible through traditional fabrication methods. The MTI approach eliminates use of metal interconnects and ceramic-metal seals, which are primary sources of stack performance degradation. Co-fired cells are less susceptible to thermal cycling stresses by using material compositions that have closely matched coefficients of thermal expansion between the cell and the interconnect. The development of this SOFC stack technology was initiated in October 1999 under the DOE cosponsored program entitled ''Affordable Multi-layer Ceramic Manufacturing for Power Systems (AMPS)''. The AMPS Program was conducted as a two-phase program: Phase I--Feasibility Assessment (10/99--9/00); and Phase II--Process Development for Co-fired Stacks (10/00-3/02). This report provides a summary of the results from Phase I and a more detailed review of the results for Phase II. Phase I demonstrated the feasibility for fabricating multi-layer, co-fired cells and interconnects and

  3. Writing about testing worries boosts exam performance in the classroom.

    PubMed

    Ramirez, Gerardo; Beilock, Sian L

    2011-01-14

    Two laboratory and two randomized field experiments tested a psychological intervention designed to improve students' scores on high-stakes exams and to increase our understanding of why pressure-filled exam situations undermine some students' performance. We expected that sitting for an important exam leads to worries about the situation and its consequences that undermine test performance. We tested whether having students write down their thoughts about an upcoming test could improve test performance. The intervention, a brief expressive writing assignment that occurred immediately before taking an important test, significantly improved students' exam scores, especially for students habitually anxious about test taking. Simply writing about one's worries before a high-stakes exam can boost test scores. PMID:21233387

  4. Writing about testing worries boosts exam performance in the classroom.

    PubMed

    Ramirez, Gerardo; Beilock, Sian L

    2011-01-14

    Two laboratory and two randomized field experiments tested a psychological intervention designed to improve students' scores on high-stakes exams and to increase our understanding of why pressure-filled exam situations undermine some students' performance. We expected that sitting for an important exam leads to worries about the situation and its consequences that undermine test performance. We tested whether having students write down their thoughts about an upcoming test could improve test performance. The intervention, a brief expressive writing assignment that occurred immediately before taking an important test, significantly improved students' exam scores, especially for students habitually anxious about test taking. Simply writing about one's worries before a high-stakes exam can boost test scores.

  5. 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.

  6. 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

  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

  8. 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.

  9. SU-E-T-119: Dosimetric and Mechanical Characteristics of Elekta Infinity LINAC with Agility MLC

    SciTech Connect

    Park, J; Xu, Q; Xue, J; Zhai, Y; An, L; Chen, Y

    2014-06-01

    Purpose: Elekta Infinity is the one of the latest generation LINAC with unique features. Two Infinity LINACs are recently commissioned at our institution. The dosimetric and mechanical characteristics of the machines are presented. Methods: Both Infinity LINACs with Agility MLC (160 leaves with 0.5 cm leaf width) are configured with five electron energies (6, 9, 12, 15, and 18 MeV) and two photon energies (6 and 15 MV). One machine has additional photon energy (10 MV). The commissioning was performed by following the manufacturer's specifications and AAPM TG recommendations. Beam data of both electron and photon beams are measured with scanning ion chambers and linear diode array. Machines are adjusted to have the dosimetrically equivalent characteristics. Results: The commissioning of mechanical and imaging system meets the tolerances by TG recommendations. The PDD{sub 10} of various field sizes for 6 and 15 MV shows < 0.5% difference between two machines. For each electron beams, R{sub 80} matches with < 0.4 mm difference. The symmetry and flatness agree within 0.8% and 0.9% differences for photon beams, respectively. For electron beams, the differences of the symmetry and flatness are within 1.2% and 0.8%, respectively. The mean inline penumbras for 6, 10, and 15 MV are respectively 5.1±0.24, 5.6±0.07, and 5.9±0.10 mm for 10x10 cm at 10 cm depth. The crossline penumbras are larger than inline penumbras by 2.2, 1.4, and 1.0 mm, respectively. The MLC transmission factor with interleaf leakage is 0.5 % for all photon energies. Conclusion: The dosimetric and mechanical characteristics of two Infinity LINACs show good agreements between them. Although the Elekta Infinity has been used in many institutions, the detailed characteristics of the machine have not been reported. This study provides invaluable information to understand the Infinity LINAC and to compare the quality of commissioning data for other LINACs.

  10. 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

  11. Technical Note: Motion-perturbation method applied to dosimetry of dynamic MLC target tracking—A proof-of-concept

    SciTech Connect

    Feygelman, Vladimir Tonner, Brian; Hunt, Dylan; Zhang, Geoffrey; Moros, Eduardo; Stambaugh, Cassandra; Nelms, Benjamin E.

    2015-11-15

    Purpose: Previous studies show that dose to a moving target can be estimated using 4D measurement-guided dose reconstruction based on a process called virtual motion simulation, or VMS. A potential extension of VMS is to estimate dose during dynamic multileaf collimator (MLC)-tracking treatments. The authors introduce a modified VMS method and quantify its performance as proof-of-concept for tracking applications. Methods: Direct measurements with a moving biplanar diode array were used to verify accuracy of the VMS dose estimates. A tracking environment for variably sized circular MLC apertures was simulated by sending preprogrammed control points to the MLC while simultaneously moving the accelerator treatment table. Sensitivity of the method to simulated tracking latency (0–700 ms) was also studied. Potential applicability of VMS to fast changing beam apertures was evaluated by modeling, based on the demonstrated dependence of the cumulative dose on the temporal dose gradient. Results: When physical and virtual latencies were matched, the agreement rates (2% global/2 mm gamma) between the VMS and the biplanar dosimeter were above 96%. When compared to their own reference dose (0 induced latency), the agreement rates for VMS and biplanar array track closely up to 200 ms of induced latency with 10% low-dose cutoff threshold and 300 ms with 50% cutoff. Time-resolved measurements suggest that even in the modulated beams, the error in the cumulative dose introduced by the 200 ms VMS time resolution is not likely to exceed 0.5%. Conclusions: Based on current results and prior benchmarks of VMS accuracy, the authors postulate that this approach should be applicable to any MLC-tracking treatments where leaf speeds do not exceed those of the current Varian accelerators.

  12. Cognitive Difficulty and Format of Exams Predicts Gender and Socioeconomic Gaps in Exam Performance of Students in Introductory Biology Courses

    ERIC Educational Resources Information Center

    Wright, Christian D.; Eddy, Sarah L.; Wenderoth, Mary Pat; Abshire, Elizabeth; Blankenbiller, Margaret; Brownell, Sara E.

    2016-01-01

    Recent reform efforts in undergraduate biology have recommended transforming course exams to test at more cognitively challenging levels, which may mean including more cognitively challenging and more constructed-response questions on assessments. However, changing the characteristics of exams could result in bias against historically underserved…

  13. Cognitive Difficulty and Format of Exams Predicts Gender and Socioeconomic Gaps in Exam Performance of Students in Introductory Biology Courses

    PubMed Central

    Wright, Christian D.; Eddy, Sarah L.; Wenderoth, Mary Pat; Abshire, Elizabeth; Blankenbiller, Margaret; Brownell, Sara E.

    2016-01-01

    Recent reform efforts in undergraduate biology have recommended transforming course exams to test at more cognitively challenging levels, which may mean including more cognitively challenging and more constructed-response questions on assessments. However, changing the characteristics of exams could result in bias against historically underserved groups. In this study, we examined whether and to what extent the characteristics of instructor-generated tests impact the exam performance of male and female and middle/high- and low-socioeconomic status (SES) students enrolled in introductory biology courses. We collected exam scores for 4810 students from 87 unique exams taken across 3 yr of the introductory biology series at a large research university. We determined the median Bloom’s level and the percentage of constructed-response questions for each exam. Despite controlling for prior academic ability in our models, we found that males and middle/high-SES students were disproportionately favored as the Bloom’s level of exams increased. Additionally, middle/high-SES students were favored as the proportion of constructed-response questions on exams increased. Given that we controlled for prior academic ability, our findings do not likely reflect differences in academic ability level. We discuss possible explanations for our findings and how they might impact how we assess our students. PMID:27252299

  14. 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…

  15. 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…

  16. Cognitive Difficulty and Format of Exams Predicts Gender and Socioeconomic Gaps in Exam Performance of Students in Introductory Biology Courses.

    PubMed

    Wright, Christian D; Eddy, Sarah L; Wenderoth, Mary Pat; Abshire, Elizabeth; Blankenbiller, Margaret; Brownell, Sara E

    2016-01-01

    Recent reform efforts in undergraduate biology have recommended transforming course exams to test at more cognitively challenging levels, which may mean including more cognitively challenging and more constructed-response questions on assessments. However, changing the characteristics of exams could result in bias against historically underserved groups. In this study, we examined whether and to what extent the characteristics of instructor-generated tests impact the exam performance of male and female and middle/high- and low-socioeconomic status (SES) students enrolled in introductory biology courses. We collected exam scores for 4810 students from 87 unique exams taken across 3 yr of the introductory biology series at a large research university. We determined the median Bloom's level and the percentage of constructed-response questions for each exam. Despite controlling for prior academic ability in our models, we found that males and middle/high-SES students were disproportionately favored as the Bloom's level of exams increased. Additionally, middle/high-SES students were favored as the proportion of constructed-response questions on exams increased. Given that we controlled for prior academic ability, our findings do not likely reflect differences in academic ability level. We discuss possible explanations for our findings and how they might impact how we assess our students.

  17. Translation termination factors function outside of translation: yeast eRF1 interacts with myosin light chain, Mlc1p, to effect cytokinesis.

    PubMed

    Valouev, I A; Urakov, V N; Kochneva-Pervukhova, N V; Smirnov, V N; Ter-Avanesyan, M D

    2004-07-01

    The translation termination factor eRF1 recognizes stop codons at the A site of the ribosome and induces peptidyl-tRNA hydrolysis at the peptidyl transferase centre. Recent data show that, besides translation, yeast eRF1 is also involved in cell cycle regulation. To clarify the mechanisms of non-translational functions of eRF1, we performed a genetic screen for its novel partner proteins. This screen revealed the gene for myosin light chain, Mlc1p, acting as a dosage suppressor of a temperature-sensitive mutation in the SUP45 gene encoding eRF1. eRF1 and Mlc1p are able to interact with each other and, similarly to depletion of Mlc1p, mutations in the SUP45 gene may affect cytokinesis. Immunofluorescent staining performed to determine localization of Mlc1p has shown that the sup45 mutation, which arrests cytokinesis, redistributed Mlc1p, causing its disappearance from the bud tip and the bud neck. The data obtained demonstrate that yeast eRF1 has an important non-translational function effecting cytokinesis via interaction with Mlc1p.

  18. Measuring mechanical properties, including isotonic fatigue, of fast and slow MLC/mIgf-1 transgenic skeletal muscle.

    PubMed

    Del Prete, Zaccaria; Musarò, Antonio; Rizzuto, Emanuele

    2008-07-01

    Contractile properties of fast-twitch (EDL) and slow-twitch (soleus) skeletal muscles were measured in MLC/mIgf-1 transgenic and wild-type mice. MLC/mIgf-1 mice express the local factor mIgf-1 under the transcriptional control of MLC promoter, selectively activated in fast-twitch muscle fibers. Isolated muscles were studied in vitro in both isometric and isotonic conditions. We used a rapid "ad hoc" testing protocol that measured, in a single procedure, contraction time, tetanic force, Hill's (F-v) curve, power curve and isotonic muscle fatigue. Transgenic soleus muscles did not differ from wild-type with regard to any measured variable. In contrast, transgenic EDL muscles displayed a hypertrophic phenotype, with a mass increase of 29.2% compared to wild-type. Absolute tetanic force increased by 21.5% and absolute maximum power by 34.1%. However, when normalized to muscle cross-sectional area and mass, specific force and normalized power were the same in transgenic and wild-type EDL muscles, revealing that mIgf-1 expression induces a functional hypertrophy without altering fibrotic tissue accumulation. Isotonic fatigue behavior did not differ between transgenic and wild-type muscles, suggesting that the ability of mIgf-1 transgenic muscle to generate a considerable higher absolute power did not affect its resistance to fatigue. PMID:18415017

  19. Safety and Efficacy of MLC601 in Iranian Patients after Stroke: A Double-Blind, Placebo-Controlled Clinical Trial

    PubMed Central

    Harandi, A. A.; Abolfazli, R.; Hatemian, A.; Ghragozlee, K.; Ghaffar-Pour, M.; Karimi, M.; Shahbegi, S.; Pakdaman, H.; Tabasi, M.; Tabatabae, A. L.; Nourian, A.

    2011-01-01

    Objective. To investigate the safety and efficacy of MLC601 (NeuroAid) as a traditional Chinese medicine on motor recovery after ischemic stroke. Methods. This study was a double-blind, placebo-controlled clinical trial on 150 patients with a recent (less than 3 month) ischemic stroke. All patients were given either MLC601 (100 patients) or placebo (50 patients), 4 capsules 3 times a day, as an add-on to standard stroke treatment for 3 months. Results. Sex, age, elapsed time from stroke onset, and risk factors in the treatment group were not significantly different from placebo group at baseline (P > .05). Repeated measures analysis showed that Fugl-Meyer assessment was significantly higher in the treatment group during 12 weeks after stroke (P < .001). Good tolerability to treatment was shown, and adverse events were mild and transient. Conclusion. MLC601 showed better motor recovery than placebo and was safe on top of standard ischemic stroke medications especially in the severe and moderate cases. PMID:21776364

  20. Safety and Efficacy of MLC601 in Iranian Patients after Stroke: A Double-Blind, Placebo-Controlled Clinical Trial.

    PubMed

    Harandi, A A; Abolfazli, R; Hatemian, A; Ghragozlee, K; Ghaffar-Pour, M; Karimi, M; Shahbegi, S; Pakdaman, H; Tabasi, M; Tabatabae, A L; Nourian, A

    2011-01-01

    Objective. To investigate the safety and efficacy of MLC601 (NeuroAid) as a traditional Chinese medicine on motor recovery after ischemic stroke. Methods. This study was a double-blind, placebo-controlled clinical trial on 150 patients with a recent (less than 3 month) ischemic stroke. All patients were given either MLC601 (100 patients) or placebo (50 patients), 4 capsules 3 times a day, as an add-on to standard stroke treatment for 3 months. Results. Sex, age, elapsed time from stroke onset, and risk factors in the treatment group were not significantly different from placebo group at baseline (P > .05). Repeated measures analysis showed that Fugl-Meyer assessment was significantly higher in the treatment group during 12 weeks after stroke (P < .001). Good tolerability to treatment was shown, and adverse events were mild and transient. Conclusion. MLC601 showed better motor recovery than placebo and was safe on top of standard ischemic stroke medications especially in the severe and moderate cases. PMID:21776364

  1. Investigation of the sag in linac secondary collimator and MLC carriage during arc deliveries

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

    In modern radiotherapy, it is vitally important to monitor the performance of all linac components including the collimation system. In this study, a simple measurement method and accurate algorithm are introduced for investigation of the secondary and tertiary collimator sag during radiotherapy arc treatments. The method is based on cine EPID images of a ball bearing marker fixed to the gantry head and determines the jaw and MLC sag in all directions relative to the reference at zero gantry angle. Analysis was performed using different field sizes and collimator angles, different linacs and different gantry rotation directions. The accuracy of the method was tested and was less than 0.02 mm. The repeatability and reproducibility of the method was 0.005 and 0.09 mm, respectively. The setup is easy and quick and the algorithm is fast and fully automatic with sub-pixel accuracy. This method is suitable to be included in the routine quality assurance of linacs to monitor the collimator system performance.

  2. 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

  3. 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.

  4. 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

  5. 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

  6. 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

  7. 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.

  8. 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

    2015-09-08

    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

  9. 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

  10. 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.

  11. 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.

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

    MedlinePlus

    ... please review our exit disclaimer . Subscribe Keep Your Vision Healthy Learn About Comprehensive Dilated Eye Exams People ... should have their eyesight tested to keep their vision at its best. Children usually have vision screening ...

  13. Remedial Study plus Retake Exams Equals Better Grades.

    ERIC Educational Resources Information Center

    Van Winkle, Lon J.

    1978-01-01

    Describes adaptation of the Retake System to larger lecture classes and tests the importance of remedial study in improving exam performance for 410 students enrolled in an interdisciplinary (chemistry, physics, and biology) science course for nonscience majors. (HM)

  14. Routine Eye Exams See Vision Problems You Miss

    MedlinePlus

    ... news/fullstory_159863.html Routine Eye Exams See Vision Problems You Miss Older people and those who ... half of people with no new symptoms or vision problems receive new prescriptions or treatment changes as ...

  15. Ace your certification exam: biofilm-based wound care.

    PubMed

    Shah, Jayesh

    2011-12-01

    Dr Jayesh Shah authors this quarterly column, consisting of 5 questions with explanations, to help you practice for your exam. In this issue, the column focuses on questions about biofilm-based wound care.

  16. Successful student remediation following repeated failures on the HESI exam.

    PubMed

    English, Jujuan B; Gordon, Debra K

    2006-01-01

    A problem-based remediation plan was developed and implemented to improve the clinical reasoning abilities and standardized test taking abilities of 9 students following 2 failures of the HESI exam. Prior to implementation students were assessed for learning needs, presence of anxiety, and learning styles. After completing the remediation sessions, all students successfully passes the HESI Exam with scores of 99.99. PMID:16913567

  17. Successful student remediation following repeated failures on the HESI exam.

    PubMed

    English, Jujuan B; Gordon, Debra K

    2004-01-01

    A problem-based remediation plan was developed and implemented to improve the clinical reasoning abilities and standardized test taking abilities of 9 students following 2 failures of the HESI exam. Prior to implementation students were assessed for learning needs, presence of anxiety, and learning styles. After completing the remediation sessions, all students successfully passed the HESI Exam with scores of 99.99. PMID:15586125

  18. Successful student remediation following repeated failures on the HESI Exam.

    PubMed

    English, Jujuan B; Gordon, Debra K

    2008-01-01

    A problem-based remediation plan was developed and implemented to improve the clinical reasoning abilities and standardized test taking abilities of 9 students following 2 failures of the HESI exam. Prior to implementation students were assessed for learning needs, presence of anxiety, and learning styles. After completing the remediation sessions, all students successfully passes the HESI Exam with scores of 99.99. PMID:18791396

  19. Again, Maryland Ranks #1 in Advanced Placement (AP) Exam Performance

    ERIC Educational Resources Information Center

    Maryland State Department of Education, 2010

    2010-01-01

    For a second year in a row, Maryland ranked first nationwide in the percentage of public school students scoring 3 or higher on at least one AP (Advanced Placement) exam. A score of 3 or higher on the 5-point scale is considered mastery of college-level work. Maryland also continues to show strong gains in the number of students taking an AP exam,…

  20. Crib sheets and exam performance in a data structures course

    NASA Astrophysics Data System (ADS)

    Hamouda, Sally; Shaffer, Clifford A.

    2016-01-01

    In this paper, we study the relationship between the use of "crib sheets" or "cheat sheets" and performance on in-class exams. Our extensive survey of the existing literature shows that it is not decisive on the questions of when or whether crib sheets actually help students to either perform better on an exam or better learn the material. We report on our own detailed analysis for a body of crib sheets created for the final exam in a junior-level Data Structures and Algorithms course. We wanted to determine whether there is any feature of the crib sheets that correlates to good exam scores. Exam performance was compared against a number of potential indicators for quality in a crib sheet. We have found that students performed significantly better on questions at the comprehension level of Bloom's taxonomy when their crib sheet contained good information on the topic, while performance on questions at higher levels of the taxonomy did not show correlation to crib sheet contents. We have also seen that students at certain levels of performance on the final exam (specifically, medium-to-high performance) did relatively better on certain questions than other students at that performance level when they had good coverage of that question's topic on their crib sheet.

  1. Does Question Structure Affect Exam Performance in the Geosciences?

    NASA Astrophysics Data System (ADS)

    Day, E. A.; D'Arcy, M. K.; Craig, L.; Streule, M. J.; Passmore, E.; Irving, J. C. E.

    2015-12-01

    The jump to university level exams can be challenging for some students, often resulting in poor marks, which may be detrimental to their confidence and ultimately affect their overall degree class. Previous studies have found that question structure can have a strong impact on the performance of students in college level exams (see Gibson et al., 2015, for a discussion of its impact on physics undergraduates). Here, we investigate the effect of question structure on the exam results of geology and geophysics undergraduate students. Specifically, we analyse the performance of students in questions that have a 'scaffolded' framework and compare them to their performance in open-ended questions and coursework. We also investigate if observed differences in exam performance are correlated with the educational background and gender of students, amongst other factors. It is important for all students to be able to access their degree courses, no matter what their backgrounds may be. Broadening participation in the geosciences relies on removing systematic barriers to achievement. Therefore we recommend that exams are either structured with scaffolding in questions at lower levels, or students are explicitly prepared for this transition. We also recommend that longitudinal studies of exam performance are conducted within individual departments, and this work outlines one approach to analysing performance data.

  2. Role of connexin 43 in vascular hyperpermeability and relationship to Rock1-MLC20 pathway in septic rats.

    PubMed

    Zhang, Jie; Yang, Guang-Ming; Zhu, Yu; Peng, Xiao-Yong; Li, Tao; Liu, Liang-Ming

    2015-12-01

    Connexin (Cx)43 has been shown to participate in several cardiovascular diseases. Increased vascular permeability is a common and severe complication in sepsis or septic shock. Whether or not Cx43 takes part in the regulation of vascular permeability in severe sepsis is not known, and the underlying mechanism has not been described. With cecal ligation and puncture-induced sepsis in rats and lipopolysaccharide (LPS)-treated vascular endothelial cells (VECs) from pulmonary veins, the role of Cx43 in increased vascular permeability and its relationship to the RhoA/Rock1 pathway were studied. It was shown that vascular permeability in the lungs, kidneys, and mesentery in sepsis rats and LPS-stimulated monolayer pulmonary vein VECs was significantly increased and positively correlated with the increased expression of Cx43 and Rock1 in these organs and cultured pulmonary vein VECs. The connexin inhibitor carbenoxolone (10 mg/kg iv) and the Rock1 inhibitor Y-27632 (2 mg/kg iv) alleviated the vascular leakage of lung, mesentery, and kidney in sepsis rats. Overexpressed Cx43 increased the phosphorylation of 20-kDa myosin light chain (MLC20) and the expression of Rock1 and increased the vascular permeability and decreased the transendothelial electrical resistance of pulmonary vein VECs. Cx43 RNA interference decreased the phosphorylation of MLC20 and the expression of Rock1 and decreased LPS-stimulated hyperpermeability of cultured pulmonary vein VECs. The Rock1 inhibitor Y-27632 alleviated LPS- and overexpressed Cx43-induced hyperpermeability of monolayer pulmonary vein VECs. This report shows that Cx43 participates in the regulation of vascular permeability in sepsis and that the mechanism is related to the Rock1-MLC20 phosphorylation pathway. PMID:26342084

  3. A Pilot Study of an Electronic Exam System at an Australian University

    ERIC Educational Resources Information Center

    Wibowo, Santoso; Grandhi, Srimannarayana; Chugh, Ritesh; Sawir, Erlenawati

    2016-01-01

    This study sought academic staff and students' views of electronic exams (e-exams) system and the benefits and challenges of e-exams in general. The respondents provided useful feedback for future adoption of e-exams at an Australian university and elsewhere too. The key findings show that students and academic staff are optimistic about the…

  4. 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…

  5. Employing Computer-Administered Exams in General Psychology: Student Anxiety and Expectations

    ERIC Educational Resources Information Center

    Schult, Carolyn A.; McIntosh, John L.

    2004-01-01

    Computer-administered exams offer many advantages, but instructors may be reluctant to use them due to concerns that computer anxiety may increase student test anxiety. Introductory psychology students (N = 265) completed surveys prior to their first exam about their anxiety related to the upcoming exam, computers in general, and taking exams on…

  6. 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)…

  7. SU-E-P-36: Evaluation of MLC Positioning Errors in Dynamic IMRT Treatments by Analyzing Dynalog Files

    SciTech Connect

    Olasolo, J; Pellejero, S; Gracia, M; Gallardo, N; Martin, M; Lozares, S; Maneru, F; Bragado, L; Miquelez, S; Rubio, A

    2015-06-15

    Purpose: To assess the accuracy of MLC positioning in Varian linear accelerator, in dynamic IMRT technique, from the analysis of dynalog files generated by the MLC controller. Methods: In Clinac accelerators (pre-TrueBeam technology), control system has an approximately 50ms delay (one control cycle time). Then, the system compares the measured position to the planned position corresponding to the next control cycle. As it has been confirmed by Varian technical support, this effect causes that measured positions appear in dynalogs one cycle out of phase with respect to the planned positions. Around 9000 dynalogs have been analyzed, coming from the three linear accelerators of our center (one Trilogy and two Clinac 21EX) equipped with a Millennium 120 MLC. In order to compare our results to recent publications, leaf positioning errors (RMS and 95th percentile) are calculated with and without delay effect. Dynalogs have been analyzed using a in-house Matlab software. Results: The RMS errors were 0.341, 0.339 and 0.348mm for each Linac; being the average error 0.343 mm. The 95th percentiles of the error were 0.617, 0.607 and 0.625; with an average of 0.617mm. A recent multi-institution study carried out by Kerns et al. found a mean leaf RMS error of 0.32mm and a 95th percentile error value of 0.64mm.Without delay effect, mean leaf RMS errors obtained were 0.040, 0.042 and 0.038mm for each treatment machine; being the average 0.040mm. The 95th percentile error values obtained were 0.057, 0.058 and 0.054 mm, with an average of 0.056mm. Conclusion: Results obtained for the mean leaf RMS error and the mean 95th percentile were consistent with the multi-institution study. Calculated error statistics with delay effect are significantly larger due to the speed proportional and systematic leaf offset. Consequently it is proposed to correct this effect in dynalogs analysis to determine the MLC performance.

  8. 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.

  9. COAMFTE accreditation and California MFT licensing exam success.

    PubMed

    Caldwell, Benjamin E; Kunker, Shelly A; Brown, Stephen W; Saiki, Dustin Y

    2011-10-01

    Professional accreditation of graduate programs in marital and family therapy (MFT) is intended to ensure the strength of the education students receive. However, there is great difficulty in assessing the real-world impact of accreditation on students. Only one measure is applied consistently to graduates of all MFT programs, regardless of accreditation status: licensure examinations. Within California, COAMFTE-accredited, regionally (WASC) accredited, and state-approved programs all may offer degrees qualifying for licensure. Exam data from 2004, 2005, and 2006 (n = 5,646 examinees on the Written Clinical Vignette exam and n = 3,408 first-time examinees on the Standard Written Exam) were reviewed to determine the differences in exam success among graduates of programs at varying levels of accreditation. Students from COAMFTE-accredited programs were more successful on both California exams than were students from other WASC-accredited or state-approved universities. There were no significant differences between (non-COAMFTE) WASC-accredited universities and state-approved programs. Differences could be related to selection effects, if COAMFTE programs initially accept students of higher quality. Implications for therapist education and training are discussed.

  10. 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

  11. 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

  12. 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.

  13. Clinical examples of 3D dose distribution reconstruction, based on the actual MLC leaves movement, for dynamic treatment techniques

    PubMed Central

    Osewski, Wojciech; Dolla, Łukasz; Radwan, Michał; Szlag, Marta; Rutkowski, Roman; Smolińska, Barbara; Ślosarek, Krzysztof

    2014-01-01

    Aim To present practical examples of our new algorithm for reconstruction of 3D dose distribution, based on the actual MLC leaf movement. Background DynaLog and RTplan files were used by DDcon software to prepare a new RTplan file for dose distribution reconstruction. Materials and methods Four different clinically relevant scenarios were used to assess the feasibility of the proposed new approach: (1) Reconstruction of whole treatment sessions for prostate cancer; (2) Reconstruction of IMRT verification treatment plan; (3) Dose reconstruction in breast cancer; (4) Reconstruction of interrupted arc and complementary plan for an interrupted VMAT treatment session of prostate cancer. The applied reconstruction method was validated by comparing reconstructed and measured fluence maps. For all statistical analysis, the U Mann–Whitney test was used. Results In the first two and the fourth cases, there were no statistically significant differences between the planned and reconstructed dose distribution (p = 0.910, p = 0.975, p = 0.893, respectively). In the third case the differences were statistically significant (p = 0.015). Treatment plan had to be reconstructed. Conclusion Developed dose distribution reconstruction algorithm presents a very useful QA tool. It provides means for 3D dose distribution verification in patient volume and allows to evaluate the influence of actual MLC leaf motion on the dose distribution. PMID:25337416

  14. 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.

  15. 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

  16. Matching marine reserve design to reserve objectives.

    PubMed Central

    Halpern, Benjamin S; Warner, Robert R

    2003-01-01

    Recent interest in using marine reserves for marine resource management and conservation has largely been driven by the hope that reserves might counteract declines in fish populations and protect the biodiversity of the seas. However, the creation of reserves has led to dissension from some interested groups, such as fishermen, who fear that reserves will do more harm than good. These perceived differences in the effect of marine reserves on various stakeholder interests has led to a contentious debate over their merit. We argue here that recent findings in marine ecology suggest that this debate is largely unnecessary, and that a single general design of a network of reserves of moderate size and variable spacing can meet the needs and goals of most stakeholders interested in marine resources. Given the high fecundity of most marine organisms and recent evidence for limited distance of larval dispersal, it is likely that reserves can both maintain their own biodiversity and service nearby non-reserve areas. In particular, spillover of larger organisms and dispersal of larvae to areas outside reserves can lead to reserves sustaining or even increasing local fisheries. Ultimately, the success of any reserve network requires attention to the uncertainty and variability in dispersal patterns of marine organisms, clear statements of goals by all stakeholder groups and proper evaluation of reserve performance. PMID:14561299

  17. Catabolic regulation analysis of Escherichia coli and its crp, mlc, mgsA, pgi and ptsG mutants

    PubMed Central

    2011-01-01

    Background Most bacteria can use various compounds as carbon sources. These carbon sources can be either co-metabolized or sequentially metabolized, where the latter phenomenon typically occurs as catabolite repression. From the practical application point of view of utilizing lignocellulose for the production of biofuels etc., it is strongly desirable to ferment all sugars obtained by hydrolysis from lignocellulosic materials, where simultaneous consumption of sugars would benefit the formation of bioproducts. However, most organisms consume glucose prior to consumption of other carbon sources, and exhibit diauxic growth. It has been shown by fermentation experiments that simultaneous consumption of sugars can be attained by ptsG, mgsA mutants etc., but its mechanism has not been well understood. It is strongly desirable to understand the mechanism of metabolic regulation for catabolite regulation to improve the performance of fermentation. Results In order to make clear the catabolic regulation mechanism, several continuous cultures were conducted at different dilution rates of 0.2, 0.4, 0.6 and 0.7 h-1 using wild type Escherichia coli. The result indicates that the transcript levels of global regulators such as crp, cra, mlc and rpoS decreased, while those of fadR, iclR, soxR/S increased as the dilution rate increased. These affected the metabolic pathway genes, which in turn affected fermentation result where the specific glucose uptake rate, the specific acetate formation rate, and the specific CO2 evolution rate (CER) were increased as the dilution rate was increased. This was confirmed by the 13C-flux analysis. In order to make clear the catabolite regulation, the effect of crp gene knockout (Δcrp) and crp enhancement (crp+) as well as mlc, mgsA, pgi and ptsG gene knockout on the metabolism was then investigated by the continuous culture at the dilution rate of 0.2 h-1 and by some batch cultures. In the case of Δcrp (and also Δmlc) mutant, TCA cycle and

  18. 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

  19. A final-exam comparison involving computer-based instruction

    NASA Astrophysics Data System (ADS)

    Jones, L. M.; Kane, Dennis; Sherwood, Bruce Arne; Avner, R. A.

    1983-06-01

    In an introductory classical mechanics course, the same final exams were given to 540 students taught in the usual way and to 486 students who received computer-based instruction. All students scored better on problems which had been made up by their own lecturer. Students in the computer-based course scored better overall. These statistically significant results are of interest not only for comparing the two forms of instruction but also for their implications on the use of exam scores for such comparisons.

  20. An improved MLC segmentation algorithm and software for step-and-shoot IMRT delivery without tongue-and-groove error

    SciTech Connect

    Luan Shuang; Wang Chao; Chen, Danny Z.; Hu, Xiaobo S.; Naqvi, Shahid A.; Wu Xingen; Yu, Cedric X.

    2006-05-15

    We present an improved multileaf collimator (MLC) segmentation algorithm, denoted by SLS{sub NOTG} (static leaf sequencing with no tongue-and-groove error), for step-and-shoot intensity-modulated radiation therapy (IMRT) delivery. SLS{sub NOTG} is an improvement over the MLC segmentation algorithm called SLS that was developed by Luan et al. [Med. Phys. 31(4), 695-707 (2004)], which did not consider tongue-and-groove error corrections. The aims of SLS{sub NOTG} are (1) shortening the treatment times of IMRT plans by minimizing their numbers of segments and (2) minimizing the tongue-and-groove errors of the computed IMRT plans. The input to SLS{sub NOTG} is intensity maps (IMs) produced by current planning systems, and its output is (modified) optimized leaf sequences without tongue-and-groove error. Like the previous SLS algorithm [Luan et al., Med. Phys. 31(4), 695-707 (2004)], SLS{sub NOTG} is also based on graph algorithmic techniques in computer science. It models the MLC segmentation problem as a weighted minimum-cost path problem, where the weight of the path is the number of segments and the cost of the path is the amount of tongue-and-groove error. Our comparisons of SLS{sub NOTG} with CORVUS indicated that for the same intensity maps, the numbers of segments computed by SLS{sub NOTG} are up to 50% less than those by CORVUS 5.0 on the Elekta LINAC system. Our clinical verifications have shown that the dose distributions of the SLS{sub NOTG} plans do not have tongue-and-groove error and match those of the corresponding CORVUS plans, thus confirming the correctness of SLS{sub NOTG}. Comparing with existing segmentation methods, SLS{sub NOTG} also has two additional advantages: (1) SLS{sub NOTG} can compute leaf sequences whose tongue-and-groove error is minimized subject to a constraint on the maximum allowed number of segments, which may be desirable in clinical situations where a treatment with the complete correction of tongue-and-groove error takes too

  1. 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.

  2. 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…

  3. Time to Say Goodbye to High School Exit Exams

    ERIC Educational Resources Information Center

    Bracey, Gerald W.

    2009-01-01

    In recent years, a concatenation of fears, pressures, and agendas has produced a new round of testing in the form of high school exit examinations. There has not, however, been an accompanying rush to see whether the exams do any good. No state has attempted to validate its test against external criteria: given the hyperbole surrounding the tests…

  4. 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,…

  5. 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…

  6. 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…

  7. 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…

  8. 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…

  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. 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…

  11. 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…

  12. 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…

  13. 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…

  14. 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…

  15. Class Attendance and Exam Performance: A Randomized Experiment

    ERIC Educational Resources Information Center

    Chen, Jennjou; Lin, Tsui-Fang

    2008-01-01

    The determination of college students' academic performance is an important issue in higher education. Whether students' attendance at lectures affects students' exam performance has received considerable attention. The authors conduct a randomized experiment to study the average attendance effect for students who choose to attend lectures, which…

  16. Student-Produced Videos for Exam Review in Mathematics Courses

    ERIC Educational Resources Information Center

    Hulsizer, Heidi

    2016-01-01

    Videos have been used in classrooms for decades, but student-produced video has recently become a viable, economical option to enhance learning. Students were asked to create videos to be used for their exam review in two different undergraduate mathematics courses: Differential Equation and Complex Analysis. Students were then surveyed about…

  17. 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)

  18. 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…

  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. The CPA Exam as a Postcurriculum Accreditation Assessment

    ERIC Educational Resources Information Center

    Barilla, Anthony G.; Jackson, Robert E.; Mooney, J. Lowell

    2008-01-01

    Business schools often attain accreditation to demonstrate program efficacy. J. A. Marts, J. D. Baker, and J. M. Garris (1988) hypothesized that candidates from Association to Advance Collegiate Schools of Business International (AACSB)-accredited accounting programs perform better on the CPA exam than do candidates from non-AACSB-accredited…

  1. [Evaluation of cytopathologic exam for diagnosis of oral chronic paracoccidioidomycosis].

    PubMed

    de Araújo, Marcelo Sivieri; Sousa, Suzana C O M; Correia, Dalmo

    2003-01-01

    With the aim of evaluating exfoliative cytology for the diagnosis of paracoccidioidomycosis oral lesions, eight patients that presented the disease were studied. The presence of fungi was demonstrated in all these cases. It was concluded that the oral exfoliative cytology exam can be effectively used in the diagnosis of paracoccidioidomycosis and contribute to the therapeutic control of oral forms of this mycosis.

  2. Does the option to rotate the Elekta Beam Modulator MLC during VMAT IMRT delivery confer advantage?--a study of 'parked gaps'.

    PubMed

    Webb, S

    2010-06-01

    When delivering intensity-modulated radiation therapy (IMRT) using the volumetric modulated arc therapy (VMAT) technique on an Elekta accelerator equipped with the Elekta Beam Modulator multileaf collimator (MLC), the orientation of the MLC, relative to the accelerator head, is generally fixed during the delivery. However, it has the ability to rotate about its axis as the gantry simultaneously rotates. This note shows that this can confer a potential advantage when planning and delivering IMRT via VMAT. A computer model has been built in which the MLC rotation angle could be varied with each control point (gantry location) within the constraints of the specified MLC rotation speed and the time available for rotation. The model was used to optimize the orientation trajectory in such a way as to minimize the number of parked gaps between leaves which are needed for some gantry orientations but not for others (and which cannot reach the shielding safety of surrounding jaws in the time available). The presented work started with the simple situation of collimating gantry-successive single convex shapes. As a broad statement some 40% reduction in such parked gaps could be achieved. The study was then extended to investigate the optimized trajectories for multiple separate concave shapes with, once again, a saving in unwanted parked gaps or unwanted over-irradiation.

  3. 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…

  4. 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

  5. Oil reserve

    SciTech Connect

    Not Available

    1991-08-01

    Argonne National Laboratory a facility run for the Department of Energy prepared a supplemental environmental impact statements for Naval Petroleum Reserve No. 1 (NPR-1) near Bakersfield, California. This paper concludes that NPR-1 might contribute to the decline of an endangered species the San Joaquin kit fox and contaminate nearby ground water. However, DOE disagreed with Argonne about the impact of NPR-1 operations on the endangered fox and nearby ground water. Because these disagreements were unresolved when DOE took over the preparation of the supplemental environmental impact statement the official draft of which is not yet completed it is unclear how Argonne's views will be reflected in the document when it is published for comment. DOE has not taken sufficient action to ensure that NPR-1 operations have complied with environmental laws and regulations governing endangered species, historic preservation, and wastewater sumping. Noncompliance with these requirements could result in legal action, fines, and even a possible shutdown of NPR-1 operations until compliance is achieved. The Department of Interior is investigating to see if prosecution is warranted for possible endangered species violations. Although DOE is trying to address possible problems, similar problems may occur at NPR-1 in the future unless DOE management controls are improved.

  6. 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.

  7. 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.

  8. The value of patient selection in demonstrating treatment effect in stroke recovery trials: lessons from the CHIMES study of MLC601 (NeuroAiD)

    PubMed Central

    Lee, Chun Fan; Wong, K. S. Lawrence; Chen, Christopher L. H.

    2015-01-01

    Abstract Objective The CHIMES Study compared MLC601 to placebo in patients with ischemic stroke of intermediate severity in the preceding 72 hours. We aimed to verify if patient selection based on two prognostic factors (ie, stroke severity and time to treatment) improves detection of a treatment effect with MLC601. Methods Analyses were performed using data from the CHIMES Study, an international, randomized, placebo‐controlled, double‐blind trial comparing MLC601 to placebo in patients with ischemic stroke of intermediate severity in the preceding 72 hours. Three subgroups, that is, onset to treatment time (OTT) ≥48 hours; baseline National Institute of Health Stroke Scale (NIHSS) ≥10; both OTT ≥48 hours and baseline NIHSS ≥10, were analyzed using modified Rankin Scale (mRS) ≤1 and a composite endpoint of mRS ≤1, Barthel Index ≥95, and NIHSS ≤1 at month 3. Results Placebo response rates were lower (ie, worse natural outcome) among subgroups with prognostic factors. Conversely, MLC601 treatment effects were significantly higher in the subgroups with prognostic factors than for the entire cohort, being highest among patients with both OTT ≥48 hours and baseline NIHSS of 10 to 14: odds ratios of 2.18 (95% CI 1.02 to 4.65) for month 3 mRS ≤1 and 3.88 (95% CI 1.03 to 14.71) for the composite endpoint. Conclusions : Patients who have moderately severe strokes and longer OTT demonstrate better treatment effects with MLC601. These factors can guide patient selection in future trials. PMID:26291445

  9. Structural determinants of interaction, trafficking and function in the ClC-2/MLC1 subunit GlialCAM involved in leukodystrophy

    PubMed Central

    Capdevila-Nortes, Xavier; Jeworutzki, Elena; Elorza-Vidal, Xabier; Barrallo-Gimeno, Alejandro; Pusch, Michael; Estévez, Raúl

    2015-01-01

    Abstract Mutations in the genes encoding the astrocytic protein MLC1, the cell adhesion molecule GlialCAM or the Cl− channel ClC-2 underlie human leukodystrophies. GlialCAM binds to itself, to MLC1 and to ClC-2, and directs these proteins to cell–cell contacts. In addition, GlialCAM dramatically activates ClC-2 mediated currents. In the present study, we used mutagenesis studies combined with functional and biochemical analyses to determine which parts of GlialCAM are required to perform these cellular functions. We found that the extracellular domain of GlialCAM is necessary for cell junction targeting and for mediating interactions with itself or with MLC1 and ClC-2. The C-terminus is also necessary for proper targeting to cell–cell junctions but is not required for the biochemical interaction. Finally, we identified the first three amino acids of the transmembrane segment of GlialCAM as being essential for the activation of ClC-2 currents but not for targeting or biochemical interaction. Our results provide new mechanistic insights concerning the regulation of the cell biology and function of MLC1 and ClC-2 by GlialCAM. Key points The extracellular domain of GlialCAM is necessary for its targeting to cell junctions, as well as for interactions with itself and MLC1 and ClC-2. The C-terminus of GlialCAM is not necessary for interaction but is required for targeting to cell junctions. The first three residues of the transmembrane segment of GlialCAM are required for GlialCAM-mediated ClC-2 activation. PMID:26033718

  10. 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.

  11. 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

  12. Using Poster Sessions as an Alternative to Written Examinations--The Poster Exam.

    ERIC Educational Resources Information Center

    Mills, Pamela A.; Sweeney, William V.; DeMeo, Stephen; Marino, Robert; Clarkson, Sandra

    2000-01-01

    Explains how to use posters as an alternative assessment method in place of traditional written exams in an integrated chemistry, physics, and mathematics course. Investigates the effectiveness of poster exams on student learning. (YDS)

  13. 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...

  14. Results of a remediation program for students at risk for failure on the NCLEX exam.

    PubMed

    Sifford, Susan; McDaniel, D Mike

    2007-01-01

    Forty-seven nursing students identified as at risk for failure on the NCLEX licensure exam took a commercially available exit exam before and after participation in a remedial test-taking course. Results indicated that participation in the course contributed to a significant increase (p < .001) in exit exam scores. PMID:17380960

  15. 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…

  16. 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…

  17. 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…

  18. How Does Student Performance on Formative Assessments Relate to Learning Assessed by Exams?

    ERIC Educational Resources Information Center

    Smith, Gary

    2007-01-01

    A retrospective analysis examines the relationships between formative assessments and exam grades in two undergraduate geoscience courses. Pair and group-work grades correlate weakly with individual exam grades. Exam performance correlates to individual, weekly online assessments. Student attendance and use of assessment feedback are also…

  19. 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…

  20. 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…

  1. Do You Prefer to Have the Text or a Sheet with Your Physics Exams?

    ERIC Educational Resources Information Center

    Hamed, Kastro M.

    2008-01-01

    Many high school and introductory college physics instructors ponder the choice between "open text" exams versus "facts and formulae sheet" exams. Other alternatives are closed book/closed notes exams or an instructor-prepared sheet of facts and relevant formulas. There is no agreement on merit. Rehfuss strongly opposes allowing students to use…

  2. 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…

  3. 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…

  4. SU-E-P-21: Impact of MLC Position Errors On Simultaneous Integrated Boost Intensity-Modulated Radiotherapy for Nasopharyngeal Carcinoma

    SciTech Connect

    Chengqiang, L; Yin, Y; Chen, L

    2015-06-15

    Purpose: To investigate the impact of MLC position errors on simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) for patients with nasopharyngeal carcinoma. Methods: To compare the dosimetric differences between the simulated plans and the clinical plans, ten patients with locally advanced NPC treated with SIB-IMRT were enrolled in this study. All plans were calculated with an inverse planning system (Pinnacle3, Philips Medical System{sub )}. Random errors −2mm to 2mm{sub )},shift errors{sub (} 2mm,1mm and 0.5mm) and systematic extension/ contraction errors (±2mm, ±1mm and ±0.5mm) of the MLC leaf position were introduced respectively into the original plans to create the simulated plans. Dosimetry factors were compared between the original and the simulated plans. Results: The dosimetric impact of the random and system shift errors of MLC position was insignificant within 2mm, the maximum changes in D95% of PGTV,PTV1,PTV2 were-0.92±0.51%,1.00±0.24% and 0.62±0.17%, the maximum changes in the D0.1cc of spinal cord and brainstem were 1.90±2.80% and −1.78±1.42%, the maximum changes in the Dmean of parotids were1.36±1.23% and −2.25±2.04%.However,the impact of MLC extension or contraction errors was found significant. For 2mm leaf extension errors, the average changes in D95% of PGTV,PTV1,PTV2 were 4.31±0.67%,4.29±0.65% and 4.79±0.82%, the averaged value of the D0.1cc to spinal cord and brainstem were increased by 7.39±5.25% and 6.32±2.28%,the averaged value of the mean dose to left and right parotid were increased by 12.75±2.02%,13.39±2.17% respectively. Conclusion: The dosimetric effect was insignificant for random MLC leaf position errors up to 2mm. There was a high sensitivity to dose distribution for MLC extension or contraction errors.We should pay attention to the anatomic changes in target organs and anatomical structures during the course,individual radiotherapy was recommended to ensure adaptive doses.

  5. 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)

  6. Should the MCAT exam be used for medical school admissions in Canada?

    PubMed

    Eskander, Antoine; Shandling, Maureen; Hanson, Mark D

    2013-05-01

    In light of the structural and content changes to the Medical College Admission Test (MCAT) to be implemented in 2015 and the recent diversity- and social-accountability-based recommendations of the Future of Medical Education in Canada (FMEC) project, the authors review and reexamine the use of the MCAT exam in Canadian medical school admissions decisions.This Perspective article uses a point-counterpoint format to discuss three main advantages and disadvantages of using the MCAT exam in the medical school admissions process, from a Canadian perspective. The authors examine three questions regarding the FMEC recommendations and the revised MCAT exam: (1) Is the MCAT exam equal and useful in Canadian admissions? (2) Does the MCAT exam affect matriculant diversity? and (3) Is the MCAT exam a strong predictor of future performance? They present the most recent arguments and evidence for and against use of the MCAT exam, with the purpose of summarizing these different perspectives for readers.

  7. 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

  8. SU-E-T-605: Performance Evaluation of MLC Leaf-Sequencing Algorithms in Head-And-Neck IMRT

    SciTech Connect

    Jing, J; Lin, H; Chow, J

    2015-06-15

    Purpose: To investigate the efficiency of three multileaf collimator (MLC) leaf-sequencing algorithms proposed by Galvin et al, Chen et al and Siochi et al using external beam treatment plans for head-and-neck intensity modulated radiation therapy (IMRT). Methods: IMRT plans for head-and-neck were created using the CORVUS treatment planning system. The plans were optimized and the fluence maps for all photon beams determined. Three different MLC leaf-sequencing algorithms based on Galvin et al, Chen et al and Siochi et al were used to calculate the final photon segmental fields and their monitor units in delivery. For comparison purpose, the maximum intensity of fluence map was kept constant in different plans. The number of beam segments and total number of monitor units were calculated for the three algorithms. Results: From results of number of beam segments and total number of monitor units, we found that algorithm of Galvin et al had the largest number of monitor unit which was about 70% larger than the other two algorithms. Moreover, both algorithms of Galvin et al and Siochi et al have relatively lower number of beam segment compared to Chen et al. Although values of number of beam segment and total number of monitor unit calculated by different algorithms varied with the head-and-neck plans, it can be seen that algorithms of Galvin et al and Siochi et al performed well with a lower number of beam segment, though algorithm of Galvin et al had a larger total number of monitor units than Siochi et al. Conclusion: Although performance of the leaf-sequencing algorithm varied with different IMRT plans having different fluence maps, an evaluation is possible based on the calculated number of beam segment and monitor unit. In this study, algorithm by Siochi et al was found to be more efficient in the head-and-neck IMRT. The Project Sponsored by the Fundamental Research Funds for the Central Universities (J2014HGXJ0094) and the Scientific Research Foundation for the

  9. 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.

  10. 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.

  11. 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…

  12. 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…

  13. How accurately can students estimate their performance on an exam and how does this relate to their actual performance on the exam?

    NASA Astrophysics Data System (ADS)

    Rebello, N. Sanjay

    2012-02-01

    Research has shown students' beliefs regarding their own abilities in math and science can influence their performance in these disciplines. I investigated the relationship between students' estimated performance and actual performance on five exams in a second semester calculus-based physics class. Students in a second-semester calculus-based physics class were given about 72 hours after the completion of each of five exams, to estimate their individual and class mean score on each exam. Students were given extra credit worth 1% of the exam points for estimating their score correct within 2% of the actual score and another 1% extra credit for estimating the class mean score within 2% of the correct value. I compared students' individual and mean score estimations with the actual scores to investigate the relationship between estimation accuracies and exam performance of the students as well as trends over the semester.

  14. 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.

  15. 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%).

  16. [Clinical exam of children from 3 to 12 years].

    PubMed

    Bourrillon, Antoine; Benoist, Grégoire

    2011-04-01

    The specific aims of clinical exams of children from 3 to 12 years of age are to assess: growth including weight and height, and body mass index (BMI) to prevent obesity, neurodevelopment both motor and intellectual including sensorial impairment to detect early learning disabilities, immunization adequacy by assessing routine schedule of vaccination and booster. The GP or paediatrician should cooperate with specialised services and nursery or primary schools to match the system of education to the needs of a given child, particularly in case of learning disabilities (normally, entry into kindergarden at 6 years of age).

  17. Emergency medicine residents’ attitudes and opinions of in-training exam preparation

    PubMed Central

    Eastin, Travis R; Bernard, Aaron W

    2013-01-01

    Purpose Emergency Medicine (EM) residents take the American Board of Emergency Medicine (ABEM) in-training exam, and performance on this exam has been shown to correlate to performance on the ABEM qualifying exam. Though many residencies have in-training exam preparation activities, there is little data on the effectiveness of these efforts. This study aimed to elicit resident perspectives about the exam and exam preparation in order to generate hypotheses and better inform future preparation efforts. Methods Second- and third-year EM residents at a single institution were interviewed using a semi-structured format. Qualitative methodology was used to analyze the data. Results Thirteen EM residents participated in the study. Eight major themes and 18 sub-themes were identified. These were further characterized as relating to the exam itself or to exam preparation. Residents generally value the in-training exam. Sixty-nine percent noted that it provided an assessment of their current knowledge and deficiencies. Thirty-eight percent noted that it improved familiarity with the qualifying exam. Regarding exam preparation, residents stated that a question format was preferred, especially when accompanying explanations were of high quality. Additionally, practical considerations, such as portability, impacted resident selection of study tools. Conclusion Residents value the in-training exam as a marker of their academic progress and for their ability to gain familiarity with the qualifying exam. They prefer question-based preparation over text-based learning, as long as there is a detailed explanation of each answer. Educators creating structured in-training review may want to focus on question-based material with detailed explanations. PMID:24062620

  18. Evaluation of patient DVH-based QA metrics for prostate VMAT: correlation between accuracy of estimated 3D patient dose and magnitude of MLC misalignment.

    PubMed

    Kadoya, Noriyuki; Saito, Masahide; Ogasawara, Makoto; Fujita, Yukio; Ito, Kengo; Sato, Kiyokazu; Kishi, Kazuma; Dobashi, Suguru; Takeda, Ken; Jingu, Keiichi

    2015-05-08

    The purpose of this study was to evaluate the accuracy of commercially available software, using patient DVH-based QA metrics, by investigating the correlation between estimated 3D patient dose and magnitude of MLC misalignments. We tested 3DVH software with an ArcCHECK. Two different calculating modes of ArcCHECK Planned Dose Perturbation (ACPDP) were used: "Normal Sensitivity" and "High Sensitivity". Ten prostate cancer patients treated with hypofractionated VMAT (67.6 Gy/26 Fr) in our hospital were studied. For the baseline plan, we induced MLC errors (-0.75, -0.5, -0.25, 0.25, 0.5, and 0.75 mm for each single bank). We calculated the dose differences between the ACPDP dose with error and TPS dose with error using gamma passing rates and using DVH-based QA metrics. The correlations between dose estimation error and MLC position error varied with each structure and metric. A comparison using 1%/1 mm gamma index showed that the larger was the MLC error-induced, the worse were the gamma passing rates. Slopes of linear fit to dose estimation error versus MLC position error for mean dose and D95 to the PTV were 1.76 and 1.40% mm-1, respectively, for "Normal Sensitivity", and -0.53 and -0.88% mm-1, respectively, for "High Sensitivity", showing better accuracy for "High Sensitivity" than "Normal Sensitivity". On the other hand, the slopes for mean dose to the rectum and bladder, V35 to the rectum and bladder and V55 to the rectum and bladder, were -1.00, -0.55, -2.56, -1.25, -3.53, and -1.85%mm-1, respectively, for "Normal Sensitivity", and -2.89, -2.39, -4.54, -3.12, -6.24, and -4.11% mm-1, respectively, for "High Sensitivity", showing significant better accuracy for "Normal Sensitivity" than "High Sensitivity". Our results showed that 3DVH had some residual error for both sensitivities. Furthermore, we found that "Normal Sensitivity" might have better accuracy for the DVH metric for the PTV and that "High Sensitivity" might have better accuracy for DVH metrics for

  19. Delivery of four-dimensional radiotherapy with TrackBeam for moving target using an AccuKnife dual-layer MLC: dynamic phantoms study.

    PubMed

    Liu, Yaxi; Shi, Chengyu; Lin, Bryan; Ha, Chul Soo; Papanikolaou, Niko

    2009-04-23

    Respiratory motion has been considered a clinical challenge for lung tumor treatments due to target motion. In this study, we aimed to perform an experimental evaluation based on dynamic phantoms using MLC-based beam tracking. TrackBeam, a prototype real-time beam tracking system, has been assembled and evaluated in our clinic. TrackBeam includes an orthogonal dual-layer micro multi-leaf collimator (DmMLC), an on-board mega-voltage (MV) portal imaging device, and an image processing workstation. With a fiducial marker implanted in a moving target, the on-board imaging device can capture the motion. The TrackBeam workstation processes the online MV fluence and detects and predicts tumor motion. The DmMLC system then dynamically repositions each leaf to form new beam apertures based on the movement of the fiducial marker. In this study, a dynamic phantom was used for the measurements. Three delivery patterns were evaluated for dosimetric verification based on radiographic films: no-motion-lung-tumor (NMLT), three-dimensional conformal radiotherapy (3DCRT), and four-dimensional tracking radiotherapy (4DTRT). The displacement between the DmMLC dynamic beam isocenter and the fiducial marker was in the range of 0.5 mm to 1.5 mm. With radiographic film analysis, the planar dose histogram difference between 3DCRT and NLMT was 48.6% and 38.0% with dose difference tolerances of 10% and 20%. The planar dose histogram difference between 4DTRT and NLMT was 15.2% and 4.0% respectively. Based-on dose volume histogram analysis, 4DTRT reduces the mean dose for the surrounding tissue from 35.4 Gy to 19.5 Gy, reduces the relative volume of the total lung from 28% to 18% at V20, and reduces the amount of dose from 35.2 Gy to 15.0 Gy at D20. The experimental results show that MLC-based real-time beam tracking delivery provides a potential solution to respiratory motion control. Beam tracking delivers a highly conformal dose to a moving target, while sparing surrounding normal tissue.

  20. 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.

  1. Examining ethics - developing a comprehensive exam for a bioethics master's program.

    PubMed

    Schonfeld, Toby; Stoddard, Hugh; Labrecque, Cory Andrew

    2014-10-01

    Assessing mastery of bioethics in a graduate program requires careful attention not simply to the content knowledge and skill development of students but also to the principles of sound assessment processes. In this article, we describe the rationale, development process, and features of the comprehensive exam we created as a culminating experience of a master's program in bioethics. The exam became the students' opportunity to demonstrate the way they were able to integrate course, textual, and practical knowledge gained throughout the experience of the program. Additionally, the exam assessed students' proficiency in the field of bioethics and their ability to critically and constructively analyze bioethical issues. In this article, we offer tips to other exam creators regarding our experiences with question and answer development, scoring of the exam, and relationships between coursework and exam preparation and completion. We also include a sample rubric for others to see how we determined which student answers were satisfactory. PMID:25033030

  2. 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

  3. 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.

  4. [Difference analysis among majors in medical parasitology exam papers by test item bank proposition].

    PubMed

    Jia, Lin-Zhi; Ya-Jun, Ma; Cao, Yi; Qian, Fen; Li, Xiang-Yu

    2012-04-30

    The quality index among "Medical Parasitology" exam papers and measured data for students in three majors from the university in 2010 were compared and analyzed. The exam papers were formed from the test item bank. The alpha reliability coefficients of the three exam papers were above 0.70. The knowledge structure and capacity structure of the exam papers were basically balanced. But the alpha reliability coefficients of the second major was the lowest, mainly due to quality of test items in the exam paper and the failure of revising the index of test item bank in time. This observation demonstrated that revising the test items and their index in the item bank according to the measured data can improve the quality of test item bank proposition and reduce the difference among exam papers.

  5. 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.

  6. Porokeratosis ptychotropica: a rare manifestation with typical histological exam.

    PubMed

    Veasey, John Verrinder; Dalapicola, Monique Coelho; Lellis, Rute Facchini; Campaner, Adriana Bittencourt; Manzione, Thiago da Silveira; Rodrigues, Maria Clarissa de Faria Soares

    2016-01-01

    Porokeratosis is a disorder of epidermal keratinization characterized clinically by a distinctive ridge-like border, and histologically by cornoid lamellae. The known clinical variants of porokeratosis are: classic porokeratosis of Mibelli, disseminated superficial (actinic) porokeratosis (DSAP), porokeratosis palmaris et plantaris disseminata, linear porokeratosis and punctate porokeratosis. In 1995, a seventh form was described as porokeratosis ptychotropica: a verrucous form resembling psoriasis involving the gluteal cleft presenting on the histological exam multiple cornoid lamellae. There are very few reports in the literature of this clinical variant. The present study describes the case of a healthy male presenting gluteal hyperkeratotic plaques for 22 years. He had been to several dermatologists, none of them had achieved a definitive diagnosis. We present a typical clinical presentation and its dermoscopy findings, in addition to histological examination that confirmed the diagnosis. PMID:27579746

  7. Porokeratosis ptychotropica: a rare manifestation with typical histological exam*

    PubMed Central

    Veasey, John Verrinder; Dalapicola, Monique Coelho; Lellis, Rute Facchini; Campaner, Adriana Bittencourt; Manzione, Thiago da Silveira; Rodrigues, Maria Clarissa de Faria Soares

    2016-01-01

    Porokeratosis is a disorder of epidermal keratinization characterized clinically by a distinctive ridge-like border, and histologically by cornoid lamellae. The known clinical variants of porokeratosis are: classic porokeratosis of Mibelli, disseminated superficial (actinic) porokeratosis (DSAP), porokeratosis palmaris et plantaris disseminata, linear porokeratosis and punctate porokeratosis. In 1995, a seventh form was described as porokeratosis ptychotropica: a verrucous form resembling psoriasis involving the gluteal cleft presenting on the histological exam multiple cornoid lamellae. There are very few reports in the literature of this clinical variant. The present study describes the case of a healthy male presenting gluteal hyperkeratotic plaques for 22 years. He had been to several dermatologists, none of them had achieved a definitive diagnosis. We present a typical clinical presentation and its dermoscopy findings, in addition to histological examination that confirmed the diagnosis. PMID:27579746

  8. A Java speech implementation of the Mini Mental Status Exam.

    PubMed

    Wang, S S; Starren, J

    1999-01-01

    The Folstein Mini Mental Status Exam (MMSE) is a simple, widely used, verbally administered test to assess cognitive function. The Java Speech Application Programming Interface (JSAPI) is a new, cross-platform interface for both speech recognition and speech synthesis in the Java environment. To evaluate the suitability of the JSAPI for interactive, patient interview applications, a JSAPI implementation of the MMSE was developed. The MMSE contains questions that vary in structure in order to assess different cognitive functions. This question variability provided an excellent test-bed to evaluate the strengths and weaknesses of JSAPI. The application is based on Java platform 2 and a JSAPI interface to the IBM ViaVoice recognition engine. Design and implementations issues are discussed. Preliminary usability studies demonstrate that an automated MMSE maybe a useful screening tool for cognitive disorders and changes.

  9. Content validity of manual spinal palpatory exams - A systematic review

    PubMed Central

    Najm, Wadie I; Seffinger, Michael A; Mishra, Shiraz I; Dickerson, Vivian M; Adams, Alan; Reinsch, Sibylle; Murphy, Linda S; Goodman, Arnold F

    2003-01-01

    Background Many health care professionals use spinal palpatory exams as a primary and well-accepted part of the evaluation of spinal pathology. However, few studies have explored the validity of spinal palpatory exams. To evaluate the status of the current scientific evidence, we conducted a systematic review to assess the content validity of spinal palpatory tests used to identify spinal neuro-musculoskeletal dysfunction. Methods Review of eleven databases and a hand search of peer-reviewed literature, published between 1965–2002, was undertaken. Two blinded reviewers abstracted pertinent data from the retrieved papers, using a specially developed quality-scoring instrument. Five papers met the inclusion/exclusion criteria. Results Three of the five papers included in the review explored the content validity of motion tests. Two of these papers focused on identifying the level of fixation (decreased mobility) and one focused on range of motion. All three studies used a mechanical model as a reference standard. Two of the five papers included in the review explored the validity of pain assessment using the visual analogue scale or the subjects' own report as reference standards. Overall the sensitivity of studies looking at range of motion tests and pain varied greatly. Poor sensitivity was reported for range of motion studies regardless of the examiner's experience. A slightly better sensitivity (82%) was reported in one study that examined cervical pain. Conclusions The lack of acceptable reference standards may have contributed to the weak sensitivity findings. Given the importance of spinal palpatory tests as part of the spinal evaluation and treatment plan, effort is required by all involved disciplines to create well-designed and implemented studies in this area. PMID:12734016

  10. Question-writing as a learning tool for students – outcomes from curricular exams

    PubMed Central

    2013-01-01

    Background Writing exam questions can be a valuable learning tool. We asked students to construct multiple choice questions for curricular exams in Internal Medicine. The questions for the particular exams were chosen from a pool of at least 300 student-written questions. The uncorrected pool was accessible to all students. We studied the influence of this approach on the students’ learning habits and their test results. We hypothesized that creating a pool of their own questions for the exams could encourage students to discuss the learning material. Methods All students had to pass 4 exams in 7 fields of Internal Medicine. Three exams were comprised of 20 questions, and we applied the new method in one of these exams. The fourth exam was comprised of 30 questions, 15 of which were chosen from a students’ pool. After all exams had been completed we asked the students to fill in a web-based questionnaire on their learning habits and their views on the new approach. The test-results were compared to the results of the lecturers’ questions that defined high and low performing students. Results A total of 102 students completed all four exams in a row, 68 of whom filled in the questionnaire. Low performing students achieved significantly better results in the students’ questions. There was no difference in the number of constructed questions between both groups of students. The new method did not promote group work significantly. However, high performing students stated a stronger wish to be rewarded by good performance. Conclusions Creating a curricular exam by choosing questions from a pool constructed by students did not influence the learning habits significantly and favored low performing students. Since the high performing students sought to be rewarded for their efforts, we do not consider the approach applied in our study to be appropriate. PMID:23787038

  11. 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.

  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. 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…

  14. The Effect of Tutoring on Math Scores for the Praxis I Exam

    ERIC Educational Resources Information Center

    Longwell-Grice, Robert; McIlheran, Janine; Schroeder, Mark; Scheele, Steve

    2013-01-01

    The Praxis test is one of a series of national teacher certification exams written and administered by the Education Testing Service (ETS) since 1947. Currently, forty states now require some form of the Praxis Series (Educational Testing Service, 2011). Using pre- and post-tests similar to the Praxis I math exam, this study examined the affect…

  15. Effects of Test Anxiety on Performance, Worry, and Emotionality in Naturally Occurring Exams

    ERIC Educational Resources Information Center

    Deffenbacher, Jerry L.; Deitz, Sheila R.

    1978-01-01

    Test performance and reported anxiety levels of high and low test-anxious subjects taking either a regular exam or an exam containing brief, written relaxation instructions were compared. High test-anxious subjects performed more poorly and reported greater worry and emotionality. Results provide greater external validity for Test Anxiety Scale.…

  16. Democracy in the Israeli Education System: The Case of the English Matriculation Exam

    ERIC Educational Resources Information Center

    Zaher, Rana

    2012-01-01

    This research investigates the extent to which indices of social justice and democratic rights are expressed in Israel in the crucial national English matriculation exam, as perceived by Palestinian Arab high school pupils studying for these exams and their English teachers. The research employed Critical Theory as a paradigm, case study as a…

  17. 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…

  18. 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…

  19. 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…

  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. A Study of Three-option and Four-option Multiple Choice Exams.

    ERIC Educational Resources Information Center

    Cooper, Terence H.

    1988-01-01

    Describes a study used to determine differences in exam reliability, difficulty, and student evaluations. Indicates that when a fourth option was added to the three-option items, the exams became more difficult. Includes methods, results discussion, and tables on student characteristics, whole test analyses, and selected items. (RT)

  2. 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…

  3. 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,…

  4. Examining the Effects of Flexible Online Exams on Students' Engagement in E-Learning

    ERIC Educational Resources Information Center

    Karaman, Selcuk

    2011-01-01

    Online assessments are essential parts of online learning. There are some debates on quality of online assessments. Nevertheless the study considered online exams as an instructional activity and aimed to examine the effects of online exams on students' engagements related to course goals. The study was conducted on two cases, which are…

  5. 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…

  6. Students' Attitudes towards Group-Based Project Exams in Two Engineering Programmes

    ERIC Educational Resources Information Center

    Dahl, Bettina; Kolmos, Anette

    2015-01-01

    At Aalborg University, engineering students spend half the time each semester in groups working on projects in a problem-based learning (PBL) curriculum. The projects are assessed through group exams, except for between 2007 and 2013 when the law forbade group-based project exams. Prior to 2007, a survey showed that students preferred the…

  7. 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…

  8. 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…

  9. 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…

  10. 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…

  11. 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…

  12. 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…

  13. Does Failing a Placement Exam Discourage Underprepared Students from Going to College?

    ERIC Educational Resources Information Center

    Martorell, Paco; McFarlin, Isaac, Jr.; Xue, Yu

    2015-01-01

    About one third of college students are required to take remedial courses. Assignment to remediation is generally made on the basis of performance on a placement exam. When students are required to take a placement exam "prior" to enrolling in college-level courses, assignment to remediation may dissuade students from actually going to…

  14. 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'…

  15. 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…

  16. 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,…

  17. 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…

  18. The Use of Orally Recorded Exam Feedback as a Supplement to Written Comments

    ERIC Educational Resources Information Center

    Jordan, Joy

    2004-01-01

    While written comments are a popular and potentially effective method of student exam feedback, these comments are often overshadowed by students' focus on their grades. In this paper I discuss the additional use of orally recorded exam feedback in introductory statistics classes of 40 or fewer students. While grading and writing comments on a…

  19. 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…

  20. 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…

  1. 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…

  2. Using the First Exam for Student Placement in Beginning Chemistry Courses

    ERIC Educational Resources Information Center

    Mills, Pamela; Sweeney, William; Bonner, Sarah M.

    2009-01-01

    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…

  3. 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…

  4. 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,…

  5. 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…

  6. 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…

  7. 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…

  8. Maryland Ranks #1 in the Nation on Advanced Placement Exams for Participation and Performance

    ERIC Educational Resources Information Center

    Maryland State Department of Education, 2009

    2009-01-01

    Maryland public high school students outperformed all others in the nation on the rigorous Advanced Placement (AP) exams, according to the College Board's fifth annual analysis of the AP program. Maryland ranked first nationwide in the percentage of public school students scoring 3 or higher on at least one AP exam. A score of 3 or higher on the…

  9. 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,…

  10. 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…

  11. 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…

  12. 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…

  13. 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…

  14. 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…

  15. Using Poster Sessions as an Alternative to Written Examination--The Poster Exam

    NASA Astrophysics Data System (ADS)

    Mills, Pamela; Demeo, Stephen; Sweeney, William V.; Marino, Robert; Clarkson, Sandra

    2000-09-01

    Poster sessions are effective communication tools common at scientific meetings. The adaptations of poster sessions to the classroom have been reported to be effective evaluation and learning tools in chemistry and other disciplines. However, poster sessions have never been used to replace a standard hourly exam. We report here the use of a poster session as an oral examination in our introductory Integrated Chemistry/Physics/Mathematics course for entering freshmen. The poster exam replaces one traditional, in-class written examination, providing an alternate method of student assessment. Students' communication and organizational skills, their depth of knowledge of a particular topic, and their conceptual understanding of the topic are probed by the poster exam. Students report that the poster exam is more enjoyable and a more effective learning tool than traditional exams.

  16. Experience using radio frequency laptops to access the electronic medical record in exam rooms.

    PubMed Central

    Dworkin, L. A.; Krall, M.; Chin, H.; Robertson, N.; Harris, J.; Hughes, J.

    1999-01-01

    Kaiser Permanente, Northwest, evaluated the use of laptop computers to access our existing comprehensive Electronic Medical Record in exam rooms via a wireless radiofrequency (RF) network. Eleven of 22 clinicians who were offered the laptops successfully adopted their use in the exam room. These clinicians were able to increase their exam room time with the patient by almost 4 minutes (25%), apparently without lengthening their overall work day. Patient response to exam room computing was overwhelmingly positive. The RF network response time was similar to the hardwired network. Problems cited by some laptop users and many of the eleven non-adopters included battery issues, different equipment layout and function, and inadequate training. IT support needs for the RF laptops were two to four times greater than for hardwired desktops. Addressing the reliability and training issues should increase clinician acceptance, making a successful general roll-out for exam room computing more likely. PMID:10566458

  17. 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)

  18. Age Starting Sigmoidoscopy or Colonoscopy Exams Maps and Data of Model-Based Small Area Estimates - Small Area Estimates

    Cancer.gov

    Age Starting Sigmoidoscopy or Colonoscopy Exams is defined as a person 18 years of age or older who must have reported that he/she thinks that at age 50 people supposed to start having sigmoidoscopy or colonoscopy exams.

  19. Sodium Butyrate Promotes Reassembly of Tight Junctions in Caco-2 Monolayers Involving Inhibition of MLCK/MLC2 Pathway and Phosphorylation of PKCβ2

    PubMed Central

    Miao, Wei; Wu, Xiujuan; Wang, Kang; Wang, Wenjing; Wang, Yumei; Li, Zhigang; Liu, Jingjing; Li, Li; Peng, Luying

    2016-01-01

    As a physiological small molecular product from the microbial fermentation of dietary fibers, butyrate plays an important role in maintaining intestinal health. Our previous works have proved that the effect of sodium butyrate (NaB) on the intestinal barrier function is mediated by activation of AMP-activated protein kinase (AMPK). However, the detailed pathway involved remains unknown. Using the calcium switch assay in the Caco-2 cell monolayer model, we found here that NaB activated AMPK mainly by increasing the calcium level, but not the ATP concentration, via promoting store-operated calcium entry (SOCE). Upon the activation of AMPK, NaB promoted the reassembly of tight junctions (TJs) based on reducing the phosphorylation of myosin II regulatory light chain (MLC2) at Ser19 and increasing phosphorylation of protein kinase C β2 (PKCβ2) at Ser660. Inhibiting (protein kinase C β) PKCβ blocked the reassembly of TJs induced by NaB in the barrier monolayer model. These results indicated that NaB could activate the calcium/calmodulin-dependent protein kinase kinase β (CaMKKβ) pathway to mediate AMPK phosphorylating, which then inhibited the phosphorylation of MLC2 and promoted the phosphorylation of PKCβ2, respectively, so that the downstream molecules of AMPK coordinately contributed to the reassembly of TJs in the Caco-2 barrier model. These results suggested a potential mechanism of butyrate for intestine homeostasis and protection. PMID:27735862

  20. 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.

  1. 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.

  2. [The role of ultrasonography exam in orbital-ocular tumors].

    PubMed

    Ciocâlteu, Alina Mihaela; Ardeleanu, S; Checheriţă, I A

    2011-01-01

    Ophthalmology is one of the specialties that have particularly benefited from the contribution of ultrasonography exam as a method of investigation. Ultrasonography is very much essential for diagnostic to complement other clinical and laboratory investigations, providing images in real time. The basic principle of diagnostic ultrasound is to study and to interpret the changes they undergo when crossing ultrasonic waves diverse biological properties different sound, and such injuries can be traced in the dynamics or can be documented on photographic paper and thus can diagnose correct certain eye diseases. The indications for performing ultrasound consist in: measurement of distances and volumes, examine difficult or inaccessible case of opaque media; ophthalmoscopic view of a mass lesion, examine the orbit or optic nerve. The advantages of ultrasound for orbital-ocular tumors are represented by the fact that ultrasound is a noninvasive method, safe, well tolerated, less expensive that the advantage of determining the position and distance from structures ocular tumor. High frequency ultrasound provides excellent resolution of 0-1 to 0.01 mm, and serial scans allow tracking progress and measuring lesion diameters tumor while allowing monitoring and evaluation of stereotactic radiation treatments applied to small tumors. In conclusion ultrasound allows not only early diagnosis of eye tumors, but accurate assessment of the proposed therapy and of the evolution of detected mass lesions or tumors.

  3. 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...

  4. Will I Do as Well on the Final Exam as I Expect? An Examination of Students' Expectations

    ERIC Educational Resources Information Center

    Burns, David J.

    2008-01-01

    Immediately prior to an exam, it is common to hear students commenting on whether they anticipate doing as well on the exam as they expect (or, in other words, whether they anticipate performing as well on the exam as the standard at which they believe they should be performing). These anticipations have received little past research attention. In…

  5. 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…

  6. 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…

  7. 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…

  8. The Effect of Online Chapter Quizzes on Exam Performance in an Undergraduate Social Psychology Course

    PubMed Central

    Johnson, Bethany C.; Kiviniemi, Marc T.

    2009-01-01

    Assigned textbook readings are a common requirement in undergraduate courses, but students often do not complete reading assignments or do not do so until immediately before an exam. This may have detrimental effects on learning and course performance. Regularly scheduled quizzes on reading material may increase completion of reading assignments and therefore course performance. This study examined the effectiveness of compulsory, mastery-based, weekly reading quizzes as a means of improving exam and course performance. Completion of reading quizzes was related to both better exam and course performance. The discussion includes recommendations for the use of quizzes in undergraduate courses. PMID:20046908

  9. Standardized testing. HIT pro exams test competencies in health IT roles.

    PubMed

    Crawford, Mark

    2011-09-01

    Healthcare needs more than EHRs, it needs people who can implement and maintain them. New federally sponsored health IT exams set workforce competencies, helping job seekers demonstrate knowledge and employers benchmark qualifications.

  10. 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)

  11. Evaluation of medical knowledge using electronic textbooks and ExaMe program on Internet.

    PubMed

    Zvárová, J; Zvára, K; Hanzlícek, P; Neustadt, J; Rosický, P; Buriánek, K; Augustinová, R; Prox, J

    1999-01-01

    In the paper we describe the function of the ExaMe program that serves for evaluation of students knowledge using Internet. Evaluation is based on the knowledge base of a given course. Two types of evaluation tests are described. The fixed test is appropriate for examination of students by the teacher in computer classroom connected to Internet. By this test the evaluation is done in the limited time period and all students are tested with the same evaluation test. The automatic test is appropriate for self-evaluation and self-study by students on remote places. The student can ask the ExaMe program for the test of different difficulty levels and state the number of questions required. Finally the first experience with the ExaMe program in practice is given. The application of the ExaMe program is shown in connection with IT EDUCTRA electronic products and electronic textbook on biomedical statistics.

  12. Relationship of the Gesell Developmental Exam and the Bracken Basic Concept Scale to Academic Achievement.

    ERIC Educational Resources Information Center

    Sterner, Anne G.; McCallum, R. Steve

    1988-01-01

    Administered the Gesell Development Exam and the Bracken Basic Concept Scale (BBCS) to kindergarten graduates (N=80). Found the BBCS may be a better predictor of achievement from a current state of readiness. (Author/ABL)

  13. 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

  14. 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.

  15. Do Resit Exams Promote Lower Investments of Study Time? Theory and Data from a Laboratory Study

    PubMed Central

    Nieuwenstein, Mark R.; de Jong, Ritske; Lorist, Monicque M.

    2016-01-01

    Although many educational institutions allow students to resit exams, a recently proposed mathematical model suggests that this could lead to a dramatic reduction in study-time investment, especially in rational students. In the current study, we present a modification of this model in which we included some well-justified assumptions about learning and performance on multiple-choice tests, and we tested its predictions in two experiments in which participants were asked to invest fictional study time for a fictional exam. Consistent with our model, the prospect of a resit exam was found to promote lower investments of study time for a first exam and this effect was stronger for participants scoring higher on the cognitive reflection test. We also found that the negative effect of resit exams on study-time investment was attenuated when access to the resit was made uncertain by making it probabilistic or dependent on obtaining a minimal, non-passing grade for the first attempt. Taken together, these results suggest that offering students resit exams may compromise the achievement of learning goals, and they raise the more general implication that second chances promote risky behavior. PMID:27711140

  16. 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.

  17. Test anxiety levels of board exam going students in Tamil Nadu, India.

    PubMed

    Mary, Revina Ann; 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

  18. 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

  19. Sleep quality during exam stress: the role of alcohol, caffeine and nicotine.

    PubMed

    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.

  20. Test anxiety levels of board exam going students in Tamil Nadu, India.

    PubMed

    Mary, Revina Ann; 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.

  1. TU-C-17A-05: Dose Domain Optimization of MLC Leaf Patterns for Highly Complicated 4Ï€ IMRT Plans

    SciTech Connect

    Nguyen, D; Yu, V; Ruan, D; Semwal, H; Cao, M; Low, D; Sheng, K; O’Connor, D

    2014-06-15

    Purpose: Highly conformal non-coplanar 4π radiotherapy plans typically require more than 20 intensity-modulated fields to deliver. A novel method to calculate multileaf collimator (MLC) leaf patterns is introduced to maximize delivery efficiency, accuracy and plan quality. Methods: 4 GBM patients, with a prescription dose of 59.4 Gy or 60 Gy, were evaluated using the 4π algorithm using 20 beams. The MLC calculation utilized a least square minimization of the dose distribution, with an anisotropic total variation regularization term to encourage piecewise continuity in the fluence maps. Transforming the fluence to the dose domain required multiplying the fluence with a sparse matrix. Exploiting this property made it feasible to solve the problem using CVX, a MATLAB-based convex modeling framework. The fluence was stratified into even step sizes, and the MLC segments, limited to 300, were calculated. The patients studied were replanned using Eclipse with the same beam angles. Results: Compared to the original 4π plan, the stratified 4π plan increased the maximum/mean dose for, in Gy, by 1.0/0.0 (brainstem), 0.5/0.2 (chiasm), 0.0/0.0 (spinal cord), 1.9/0.3 (L eye), 0.7/0.2 (R eye), 0.4/0.4 (L lens), 0.3/0.3 (R lens), 1.0/0.8 (L Optical Nerve), 0.5/0.3 (R Optical Nerve), 0.3/0.2 (L Cochlea), 0.1/0.1 (R Cochlea), 4.6/0.2 (brain), 2.4/0.1 (brain-PTV), 5.1/0.9 (PTV). Compared to Eclipse, which generated an average of 607 segments, the stratified plan reduced (−) or increased (+) the maximum/mean dose, in Gy, by −10.2/−4.1 (brainstem), −10.5/−8.9 (chiasm), +0.0/−0.1 (spinal cord), −4.9/−3.4 (L eye), −4.1/−2.5 (R eye), −2.8/−2.7 (L lens), −2.1/−1.9 (R lens), −7.6/−6.5 (L Optical Nerve), −8.9/−6.1 (R Optical Nerve), −1.3/−1.9 (L Cochlea), −1.8/−1.8 (R Cochlea), +1.7/−2.1 (brain), +3.2/−2.6 (brain-PTV), +1.8/+0.3 Gy (PTV. The stratified plan was also more homogeneous in the PTV. Conclusion: This novel solver can transform

  2. 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

  3. 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.

  4. Realisation of the guidelines for faculty-internal exams at the Department of General Medicine at the University of Munich: Pushing medical exams one step ahead with IMSm.

    PubMed

    Boeder, Niklas; Holzer, Matthias; Schelling, Jörg

    2012-01-01

    Graded exams are prerequisites for the admission to the medical state examination. Accordingly the exams must be of good quality in order to allow benchmarking with the faculty and between different universities. Criteria for good quality need to be considered - namely objectivity, validity and reliability. The guidelines for the processing of exams published by the GMA are supposed to help maintaining those criteria. In 2008 the Department of General Medicine at the University of Munich fulfils only 14 of 18 items. A review process, appropriate training of the staff and the introduction of the IMSm software were the main changes that helped to improve the 'GMA-score' to 30 fulfilled items. We see the introduction of the IMSm system as our biggest challenge ahead. IMSm helps to streamline the necessary workflow and improves their quality (e.g. by the detection of cueing, item analysis). Overall, we evaluate the steps to improve the exam process as very positive. We plan to engage co-workers outside the department to assist in the various review processes in the future. Furthermore we think it might be of value to get into contact with other departments and faculties to benefit from each other's question pools.

  5. 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…

  6. Testing the methodology for dosimetry audit of heterogeneity corrections and small MLC-shaped fields: Results of IAEA multi-center studies

    PubMed Central

    Izewska, Joanna; Wesolowska, Paulina; Azangwe, Godfrey; Followill, David S.; Thwaites, David I.; Arib, Mehenna; Stefanic, Amalia; Viegas, Claudio; Suming, Luo; Ekendahl, Daniela; Bulski, Wojciech; Georg, Dietmar

    2016-01-01

    Abstract The International Atomic Energy Agency (IAEA) has a long tradition of supporting development of methodologies for national networks providing quality audits in radiotherapy. A series of co-ordinated research projects (CRPs) has been conducted by the IAEA since 1995 assisting national external audit groups developing national audit programs. The CRP ‘Development of Quality Audits for Radiotherapy Dosimetry for Complex Treatment Techniques’ was conducted in 2009–2012 as an extension of previously developed audit programs. Material and methods. The CRP work described in this paper focused on developing and testing two steps of dosimetry audit: verification of heterogeneity corrections, and treatment planning system (TPS) modeling of small MLC fields, which are important for the initial stages of complex radiation treatments, such as IMRT. The project involved development of a new solid slab phantom with heterogeneities containing special measurement inserts for thermoluminescent dosimeters (TLD) and radiochromic films. The phantom and the audit methodology has been developed at the IAEA and tested in multi-center studies involving the CRP participants. Results. The results of multi-center testing of methodology for two steps of dosimetry audit show that the design of audit procedures is adequate and the methodology is feasible for meeting the audit objectives. A total of 97% TLD results in heterogeneity situations obtained in the study were within 3% and all results within 5% agreement with the TPS predicted doses. In contrast, only 64% small beam profiles were within 3 mm agreement between the TPS calculated and film measured doses. Film dosimetry results have highlighted some limitations in TPS modeling of small beam profiles in the direction of MLC leave movements. Discussion. Through multi-center testing, any challenges or difficulties in the proposed audit methodology were identified, and the methodology improved. Using the experience of these

  7. Washington: Hanford Nuclear Reservation

    Atmospheric Science Data Center

    2014-05-15

    ... area around the Hanford Nuclear Reservation near Richland, Washington. On June 27, 2000, a fire in the dry sagebrush was sparked by an ... CA, for NASA's Science Mission Directorate, Washington, D.C. The Terra spacecraft is managed by NASA's Goddard Space Flight Center, ...

  8. School Shootings Stun Reservation

    ERIC Educational Resources Information Center

    Borja, Rhea R.; Cavanagh, Sean

    2005-01-01

    This article deals with the impact brought by the school shootings at Red Lake Indian Reservation in Minnesota to the school community. A deeply troubled 16-year-old student shot and killed seven other people and himself at a high school. The nation's deadliest school attack since the 1999 slayings at Colorado's suburban Columbine High School took…

  9. Managing exam stress using UMTS phones: the advantage of portable audio/video support.

    PubMed

    Riva, Giuseppe; Grassi, Alessandra; Villani, Daniela; Gaggioli, Andrea; Preziosa, Alessandra

    2007-01-01

    Test-taking anxiety or stress is very common among university students. It can be very distressing and sometimes debilitating. Exam anxiety involves physical components and emotional components that may be taken into account for managing and reducing anxiety. An approach to control exam anxiety is to learn how to regulate emotions. To help students in managing exam stress we developed a specific protocol based on mobile narratives--multimedia narratives experienced on UMTS/3G phones. 30 female university students (M=23.48; sd=1.24) who were going to perform an exam within a week were included in the trial. They were randomly divided in five groups according to the type and mobility of the medium used: (1) audio only narrative (CD at home); (2) audio only narrative (portable MP3); (3) audio and video narrative (DVD at home); (4) audio and video narrative (UMTS based); (5) control group. Audio/video narratives induced a reduction in exam anxiety in more than 80% of the sample vs 50% of the MP3 sample and 0% of the CD sample. Further, all the users who experienced mobile narratives on UMTS phones were able to relax before the exam, against 50% of DVD users and 33% of audio-only users. The trial showed a better efficacy of mobile narratives experienced on UMTS phones in reducing the level of exam stress and in helping the student to relax. These results suggest that for the specific sample considered--Italian university students--the media used for providing an anti-stress protocol has a clear impact on its efficacy. PMID:17377312

  10. Do You Prefer to Have the Text or a Sheet with Your Physics Exams?

    NASA Astrophysics Data System (ADS)

    Hamed, Kastro M.

    2008-05-01

    Many high school and introductory college physics instructors ponder the choice between "open text" exams versus "facts and formulae sheet" exams. Other alternatives are closed book/closed notes exams or an instructor-prepared sheet of facts and relevant formulas. There is no agreement on merit. Rehfuss strongly opposes allowing students to use formula sheets while taking physics exams despite acknowledging that such use is common practice. Cone2 responded to Rehfuss by defending the use of such sheets and outlining the benefits of a "cheat sheet." Debate over the use of a "cheat sheet" or other resources during exams is not limited to the physics community. Skidmore and Aagaard3 studied the relationship between testing conditions and student test scores for students in teacher education. Two decades earlier Boniface,4 Dorsal and Cundiff,5 and Hindman6 published papers on the use of texts and/or sheets during examinations in psychology and education. Others, such as Pullen et al.7 focused on studying the discarded cheat sheets themselves. Humorously, in October 2005 The New York Times8 reported an unusual museum exhibit of "cheat sheets" and the different ways students had cheated at a particular university.

  11. Improving consistency in large laboratory courses: a design for a standardized practical exam.

    PubMed

    Chen, Xinnian; Graesser, Donnasue; Sah, Megha

    2015-06-01

    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 administered by asking students to move from station to station to answer questions, apply knowledge gained during laboratory experiments, interpret data, and identify various tissues and organs using various microscopic and gross specimens. This approach puts a stringent time limit on all questions regardless of the level of difficulty and also invariably increases the potential risk of cheating. To avoid potential cheating in laboratory courses with multiple sections, the setup for practical exams is often changed in some way between sections. In laboratory courses with multiple instructors or teaching assistants, practical exams may be handled inconsistently among different laboratory sections, due to differences in background knowledge, perceptions of the laboratory goals, or prior teaching experience. In this article, we describe a design for a laboratory practical exam that aims to align the assessment questions with well-defined laboratory learning objectives and improve the consistency among all laboratory sections.

  12. Poor ovarian reserve.

    PubMed

    Jirge, Padma Rekha

    2016-01-01

    Poor ovarian reserve (POR) is an important limiting factor for the success of any treatment modality for infertility. It indicates a reduction in quantity and quality of oocytes in women of reproductive age group. It may be age related as seen in advanced years of reproductive life or may occur in young women due to diverse etiological factors. Evaluating ovarian reserve and individualizing the therapeutic strategies are very important for optimizing the success rate. Majority or women with POR need to undergo in vitro fertilization to achieve pregnancy. However, pregnancy rate remains low despite a plethora of interventions and is associated with high pregnancy loss. Early detection and active management are essential to minimize the need for egg donation in these women. PMID:27382229

  13. Poor ovarian reserve

    PubMed Central

    Jirge, Padma Rekha

    2016-01-01

    Poor ovarian reserve (POR) is an important limiting factor for the success of any treatment modality for infertility. It indicates a reduction in quantity and quality of oocytes in women of reproductive age group. It may be age related as seen in advanced years of reproductive life or may occur in young women due to diverse etiological factors. Evaluating ovarian reserve and individualizing the therapeutic strategies are very important for optimizing the success rate. Majority or women with POR need to undergo in vitro fertilization to achieve pregnancy. However, pregnancy rate remains low despite a plethora of interventions and is associated with high pregnancy loss. Early detection and active management are essential to minimize the need for egg donation in these women. PMID:27382229

  14. Reserves in Western Basins

    SciTech Connect

    Caldwell, R.H.; Cotton, B.W.

    1993-12-31

    The objective of this project is to investigate the reserves potential of overpressured tight (OPT) gas reservoirs in three Rocky Mountain basins. These are the Greater Green River Basin (GGRB), Uinta Basin and Piceance Basin. By documenting productive characteristics in these basins and characterizing the nature of the vast gas resources in place, the reserves potential may be understood and quantified. Through this understanding, it is hoped that the oil and gas industry will be encouraged to pursue exploitation of this resource. At this point in time, the GGRB work has been completed and the final report submitted for publication. Work on the Uinta basin has just commenced and work on the Piceance basin will commence next year. Since the GGRB portion of this project has been completed, further discussion centers upon this Basin.

  15. 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)

  16. Inference on cancer screening exam accuracy using population-level administrative data.

    PubMed

    Jiang, H; Brown, P E; Walter, S D

    2016-01-15

    This paper develops a model for cancer screening and cancer incidence data, accommodating the partially unobserved disease status, clustered data structures, general covariate effects, and dependence between exams. The true unobserved cancer and detection status of screening participants are treated as latent variables, and a Markov Chain Monte Carlo algorithm is used to estimate the Bayesian posterior distributions of the diagnostic error rates and disease prevalence. We show how the Bayesian approach can be used to draw inferences about screening exam properties and disease prevalence while allowing for the possibility of conditional dependence between two exams. The techniques are applied to the estimation of the diagnostic accuracy of mammography and clinical breast examination using data from the Ontario Breast Screening Program in Canada. PMID:26278587

  17. Inference on cancer screening exam accuracy using population-level administrative data.

    PubMed

    Jiang, H; Brown, P E; Walter, S D

    2016-01-15

    This paper develops a model for cancer screening and cancer incidence data, accommodating the partially unobserved disease status, clustered data structures, general covariate effects, and dependence between exams. The true unobserved cancer and detection status of screening participants are treated as latent variables, and a Markov Chain Monte Carlo algorithm is used to estimate the Bayesian posterior distributions of the diagnostic error rates and disease prevalence. We show how the Bayesian approach can be used to draw inferences about screening exam properties and disease prevalence while allowing for the possibility of conditional dependence between two exams. The techniques are applied to the estimation of the diagnostic accuracy of mammography and clinical breast examination using data from the Ontario Breast Screening Program in Canada.

  18. Influence of a revision course and the gender of examiners on the grades of the final ENT exam – a retrospective review of 3961 exams

    PubMed Central

    Grasl, Matthäus C.; Seemann, Rudolf; Hanisch, Michael; Heiduschka, Gregor; Kremser, Karl; Thurnher, Dietmar

    2015-01-01

    Revision courses should repeat already acquired knowledge and skills and mostly provide a basis for passing the following exam. Aim: The aim of the study is to investigate the influence of a previously attended revision course on the grades achieved in a final exam (Ear, Nose and Throat Diseases). Additionally we ask the question whether the gender of the examiners plays a role concerning the marks or not. Methods: 3961 exams at the Department of Ear, Nose and Throat (ENT) Diseases in Vienna were investigated, 725 with revision course (experimental group) and 3236 without previous revision course (comparison group). The revision courses were performed in a standardized way concerning form and content, interactive and case based. Both groups were examined uniform in regard to topics and time duration. 16 male and 6 female examiners were involved. The grading followed a five–level scale. The examination marks were calculated in the arithmetic mean and median value for the entire sample, gender dependence was calculated according to the Wilcoxon-Mann-Whitney-Test. The inferential statistics included single- and multiple factorial analyses of variance as well as uni- and multivariate regression models. Results: The experimental group achieved a grade average of 2.54 compared with 2.46 for the comparison group. Splitting up into male and female examiners, an average of 2.54 and 2.58 resp. for the experimental group and 2.44 and 2.61 resp. for the comparison group resulted. Female examiner marked significantly lower grades in comparison to their male colleagues (P= 0.001926). Conclusions: The ENT revision course did not improve the grade averages of the final ENT exam. Female examiners grade stricter than male examiners. There was no difference concerning grades 4 (pass) and 5 (fail) but female examiners grade less with mark 1. PMID:26483851

  19. In-vivo hip arthrokinematics during supine clinical exams: Application to the study of femoroacetabular impingement.

    PubMed

    Kapron, Ashley L; Aoki, Stephen K; Peters, Christopher L; Anderson, Andrew E

    2015-08-20

    Visualization of hip articulation relative to the underlying anatomy (i.e., arthrokinematics) is required to understand hip dysfunction in femoroacetabular (FAI) patients. In this exploratory study, we quantified in-vivo arthrokinematics of a small cohort of asymptomatic volunteers and three symptomatic patients with varying FAI deformities during the passive impingement, FABER, and rotational profile exams using dual fluoroscopy and model-based tracking. Joint angles, joint translations, and relative pelvic angles were calculated. Compared to the 95% confidence interval of the asymptomatic cohort, FAI patients appeared to have decreased adduction and internal rotation during the impingement exam and greater flexion and less abduction/external rotation in the FABER exam. During the rotational profile, only the FAI patient with the most severe deformities demonstrated considerable rotation deficits. In all participants, contact between the labrum and femoral head/neck limited motion during the impingement exam, but not the rotational profile. Substantial pelvic motion was measured during the impingement exam and FABER test in all participants. Femoral translation along any given anatomical direction ranged between 0.69 and 4.1mm. These results suggest that hip articulation during clinical exams is complex in asymptomatic hips and hips with FAI, incorporating pelvic motion and femur translation. Range of motion appears to be governed by femur-labrum contact and other soft tissue constraints, suggesting that current computer simulations that rely on direct bone contact to predict impingement may be unrealistic. Additional research is necessary to confirm these preliminary results. Still, dual fluoroscopy data may serve to validate existing software platforms or create new programs that better-represent hip arthrokinematics. PMID:25997726

  20. A unified optimization platform comparison of three radiosurgery techniques: Gamma Knife, BrainLAB micro-MLC, and NOMOS MIMiC

    NASA Astrophysics Data System (ADS)

    Cheek, Dennis Allen

    The objective of this research is to build a unified optimization treatment planning system in order to accurately compare the three modalities unburdened by underlying assumptions that could alter the outcome of the comparison. The hypothesis for the dissertation is: Three photon radiosurgery delivery mechanisms are utilized for the delivery of necrotic radiation doses to a cranial lesion: the Gamma Knife, micro-MLC intensity modulated radiosurgery, and MIMiC based intensity modulated radiosurgery. Each modality has its own strength and weaknesses in their ability to deliver radiosurgery treatments. We hypothesize the MIMiC based intensity modulated radiosurgery will allow improvements to radiosurgery treatments compared to the conventional Gamma Knife and micro-MLC, as quantified by the following metrics: isodose line display, dose volume histograms, Ian Paddick conformality index, homogeneity index, and objective function score. The specific aims for the dissertation are: (1) Develop a radiosurgery treatment planning software platform to import image and structure data and to offer evaluation tools. The evaluation tools will include isodose line display, dose volume histogram, Ian Paddick conformality index, homogeneity index, and objective function score. (2) Develop a simulated annealing optimization routine, with an associated objective function, that will determine the optimal treatment plan for the defined solution space. The objective, or cost function will be based on Ian Paddick conformality index. (3) Perform multiple repeat optimizations of each modality for a given lesion in order to gather statistical information about the minimum solution found. This test will quantify the ability of the optimization routine to arrive at a similar local minimum and therefore quantify the reliability of the comparison performed in specific aim five. (4) Investigate the affect of the Gamma Knife's shot limitation on the resulting dose distribution for a given lesion

  1. 77 FR 21846 - Reserve Requirements of Depository Institutions: Reserves Simplification

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-12

    ... liabilities of depository institutions for the purpose of implementing monetary policy. The Board's Regulation... monetary policy. If the Federal Reserve changes its monetary policy framework, which includes the payment... affect the Federal Reserve's ability to implement monetary policy in the event that all...

  2. Reappraising Stress Arousal Improves Performance and Reduces Evaluation Anxiety in Classroom Exam Situations

    ERIC Educational Resources Information Center

    Jamieson, Jeremy P.; Peters, Brett J.; Greenwood, Emily J.; Altose, Aaron J.

    2016-01-01

    For students to thrive in the U.S. educational system, they must successfully cope with omnipresent demands of exams. Nearly all students experience testing situations as stressful, and signs of stress (e.g., racing heart) are typically perceived negatively. This research tested the efficacy of a psychosituational intervention targeting cognitive…

  3. American Diploma Project (ADP) End-of-Course Exams: 2010 Annual Report

    ERIC Educational Resources Information Center

    Achieve, Inc., 2010

    2010-01-01

    To assess the raised expectations of college and career readiness for all students, a group of American Diploma Project (ADP) Network states formed the ADP Assessment Consortium in 2005. The Consortium created Algebra I and II end-of-course exams, based in large part on Achieve's ADP mathematics benchmarks, which would provide an honest assessment…

  4. Circumscribed Agency: The Relevance of Standardized College Entrance Exams for Low SES High School Students

    ERIC Educational Resources Information Center

    Deil-Amen, Regina; Tevis, Tenisha LaShawn

    2010-01-01

    The authors interviewed Black and Latino students from five high-poverty high schools as they attempted to make the transition into college. Their ability to exert individual agency with regard to their entrance exams and their college transition was circumscribed by the messages and behavioral norms that dominated their low-performing high school…

  5. Effect of Curriculum Change on Exam Performance in a 4-Week Psychiatry Clerkship

    ERIC Educational Resources Information Center

    Niedermier, Julie; Way, David; Kasick, David; Kuperschmidt, Rada

    2010-01-01

    Objective: The authors investigated whether curriculum change could produce improved performance, despite a reduction in clerkship length from 8 to 4 weeks. Methods: The exam performance of medical students completing a 4-week clerkship in psychiatry was compared to national data from the National Board of Medical Examiners' Psychiatry Subject…

  6. A Working Model for Assessing Spanish Heritage Language Learners' Language Proficiency through a Placement Exam

    ERIC Educational Resources Information Center

    Fairclough, Marta

    2012-01-01

    Having a clear idea of the knowledge in the heritage language that a student brings to the classroom is essential for a successful language-learning experience; for that reason, research in heritage language education has been focusing increasingly on assessment issues, especially language placement exams. Professionals debate whether assessment…

  7. Attitudes toward Statistics and Their Relationship with Short- and Long-Term Exam Results

    ERIC Educational Resources Information Center

    Vanhoof, Stijn; Sotos, Ana Elisa Castro; Onghena, Patrick; Vershaffel, Lieven; Van Dooren, Wim; Van den Noortgate, Wim; Leuven, Katholieke Universiteit

    2006-01-01

    This study uses the Attitudes Toward Statistics (ATS) scale (Wise 1985) to investigate the attitudes toward statistics and the relationship of those attitudes with short- and long-term statistics exam results for university students taking statistics courses in a five year Educational Sciences curriculum. Compared to the findings from previous…

  8. Differences in Classroom versus Online Exam Performance Due to Asynchronous Discussion

    ERIC Educational Resources Information Center

    Jorczak, Robert L.; Dupuis, Danielle N.

    2014-01-01

    This study compares undergraduate student exam performance of classroom and online course sections that have nearly identical instructional designs. The sections differed only in lecturing and peer discussion activities that are typical differences of classroom and online instruction. Classroom discussion activities were synchronous speech and…

  9. Candidate Performance on the Business Environment and Concepts Section of the CPA Exam

    ERIC Educational Resources Information Center

    Lindsay, D. H.; Tan, K. B.; Campbell, Annhenrie

    2009-01-01

    This paper examines how differences in curricular design of undergraduate accounting programs influence pass rates on the Business Environment and Concepts Section of the CPA Exam. The association of the pass rate of a school's accounting graduates to the design of the schools accounting program and to other school characteristics was examined…

  10. Class of 2015 Advanced Placement and International Baccalaureate Exam Participation and Performance. Memorandum

    ERIC Educational Resources Information Center

    Navarro, Maria V.

    2016-01-01

    This memorandum describes the Advanced Placement (AP) and International Baccalaureate (IB) exams participation and performance of 2013 to 2015 public school graduates in Montgomery County Public Schools (MCPS) and the state of Maryland. The results are disaggregated by demographics and high schools. Students in the MCPS Class of 2015 continued to…

  11. What To Look for in ESL Admission Tests: Cambridge Certificate Exams, IELTS, and TOEFL.

    ERIC Educational Resources Information Center

    Chalhoub-Deville, Micheline; Turner, Carolyn E.

    2000-01-01

    Familiarizes test users with issues to consider when employing assessments for screening and admission purposes. Examines the purpose, content, and scoring methods of three English-as-a-Second-Language admissions tests--the Cambridge certificate exams, International English Language Teaching System, and Test of English as a Foreign…

  12. Retrieving Essential Material at the End of Lectures Improves Performance on Statistics Exams

    ERIC Educational Resources Information Center

    Lyle, Keith B.; Crawford, Nicole A.

    2011-01-01

    At the end of each lecture in a statistics for psychology course, students answered a small set of questions that required them to retrieve information from the same day's lecture. These exercises constituted retrieval practice for lecture material subsequently tested on four exams throughout the course. This technique is called the PUREMEM…

  13. From Napoleon to Sarkozy: Two Hundred Years of the "Baccalaureat" Exam

    ERIC Educational Resources Information Center

    El Atia, Samira

    2008-01-01

    In March 17th, 2008, the Baccalaureat exam in France celebrates 200 years since its establishment. The Baccalaureat is the French national examination to complete secondary education and determine admission to higher education. A byproduct of several factors: the strict educational philosophy of the Jesuits, the radical reforms of the French…

  14. Predictors of the Elementary School Proficiency Exams and Issues of Equality in Educational Facilities

    ERIC Educational Resources Information Center

    Erdogan, Irfan; Meseci Giorgetti, Filiz; Cifcili, Vakur

    2011-01-01

    The main purpose of this study is to determine whether school/student, classroom/student, teacher/student ratio, and the Human Development Index (I.G.E.) rates by province predict a province's total 6th and 7th grade Elementary School Proficiency Exam (SBS) scores. To determine the relationships between the province's total 6th and 7th grade SBS…

  15. Sleep Patterns and Academic Performance during Preparation for College Entrance Exam in Chinese Adolescents

    ERIC Educational Resources Information Center

    Wang, Guanghai; Ren, Fen; Liu, Zhijun; Xu, Guangxing; Jiang, Fan; Skora, Elizabeth; Lewin, Daniel S.

    2016-01-01

    Background: Deficient sleep is linked to detrimental outcomes in health and school performance for adolescents. This study characterized sleep patterns in Chinese adolescents preparing for the College Entrance Exam (CEE) and evaluated the association between sleep patterns, self-rated academic performance, and the CEE scores. Methods: A sample of…

  16. Predicting Success, Preventing Failure: An Investigation of the California High School Exit Exam

    ERIC Educational Resources Information Center

    Zau, Andrew C.; Betts, Julian R.

    2008-01-01

    Many educators, parents, and policymakers continue to call for reforms to the California High School Exit Exam (CAHSEE), citing concern about the 10 percent of California students who do not graduate because of their failure to pass the test. By law, current funding for tutoring those at risk of failing the CAHSEE is targeted at those in grade 12…

  17. A history and overview of the certification exam for medical dosimetrists

    SciTech Connect

    Pusey, Damien; Smith, Lisette; Zeman, Elaine M.; Adams, Robert . E-mail: Robert_Adams@med.unc.edu

    2005-06-30

    During the last century, the creation and implementation of board certification has had a powerful impact on the medical community. Board certification has helped to shape the scope and practice of medical professionals and the care they provide, as well as to influence the way the health insurance industry sets standards for reimbursement. One profession that offers board certification to its members is medical dosimetry. The Medical Dosimetrist Certification Board exam has been administered since 1988 and its content covers a broad spectrum of information from the radiation therapy sciences. The exam has strict application requirements and is rather difficult to pass. Those who pass the exam can then call themselves Certified Medical Dosimetrists. For data purposes of this study, several members of the dosimetry community were solicited to participate in a survey regarding the exam's content and history, and to provide relevant statistical data. Currently 2,177 medical dosimetrists are board certified, with an additional 1,500 estimated to be working without certification. Although board certification is not currently required to practice medical dosimetry, new legislation known as the CARE Bill could change this. The CARE Bill, if passed, would mandate nationwide compulsory licensure and/or certification for medical dosimetrists and other medical professionals who want to work in radiation-related health care. Health maintenance organizations and other insurance carriers may likewise require certification for reimbursement purposes.

  18. Rethinking Exams and Letter Grades: How Much Can Teachers Delegate to Students?

    ERIC Educational Resources Information Center

    Kitchen, Elizabeth; King, Summer H.; Robison, Diane F.; Sudweeks, Richard R.; Bradshaw, William S.; Bell, John D.

    2006-01-01

    In this article we report a 3-yr study of a large-enrollment Cell Biology course focused on developing student skill in scientific reasoning and data interpretation. Specifically, the study tested the hypothesis that converting the role of exams from summative grading devices to formative tools would increase student success in acquiring those…

  19. VA State Profile. Virginia: Standards of Learning (SOL) End-of-Course Exams

    ERIC Educational Resources Information Center

    Center on Education Policy, 2010

    2010-01-01

    This paper provides information about Virginia's Standards of Learning (SOL) End-of-Course Exams. The purpose of the end-of-course assessments is to measure the achievement of students on the Standards of Learning adopted by the Virginia Board of Education for specific high school courses, and to ensure that students graduating from Virginia…

  20. Analysis of Effects of Placement Exam Scores on Grading Practices: A Thwarted Esoteric Study.

    ERIC Educational Resources Information Center

    Roberts, Frank C.

    The purpose of this study was to analyze the effects of entrance examination scores, used for placement, on grading practices of teachers at Antelope Valley College (California). Correlations between students' GPA and their entrance exam scores were calculated. These were compared with correlations between grades given by 10 instructors and the…

  1. Comparing Intentions to Use University-Provided vs Vendor-Provided Multibiometric Authentication in Online Exams

    ERIC Educational Resources Information Center

    Levy, Yair; Ramim, Michelle M.; Furnell, Steven M.; Clarke, Nathan L.

    2011-01-01

    Purpose: Concerns for information security in e-learning systems have been raised previously. In the pursuit for better authentication approaches, few schools have implemented students' authentication during online exams beyond passwords. This paper aims to assess e-learners' intention to provide multibiometric data and use of multibiometrics…

  2. The Present in Flemish Secondary History Education through the Lens of Written History Exams

    ERIC Educational Resources Information Center

    Van Nieuwenhuyse, Karel; Wils, Kaat; Clarebout, Geraldine; Verschaffel, Lieven

    2015-01-01

    The present plays an important part in history education, in particular in efforts to make the study of the past relevant for today. This contribution examines how the relationship between past and present is dealt with in current Flemish secondary history education by analyzing 190 written history exams for the 11th and 12th grade. Ten percent of…

  3. Improvements to an Electrical Engineering Skill Audit Exam to Improve Student Mastery of Core EE Concepts

    ERIC Educational Resources Information Center

    Parent, D. W.

    2011-01-01

    The San Jose State University Electrical Engineering (EE) Department implemented a skill audit exam for graduating seniors in 1999 with the purpose of assessing the teaching and the students' mastery of core concepts in EE. However, consistent low scores for the first years in which the test was administered suggested that students had little…

  4. Proposals for Standardizing and Improving the Policy of Adding Points on the Entrance Exam

    ERIC Educational Resources Information Center

    Yuhong, Deng

    2013-01-01

    This article reviews policies for adding points on the College Entrance Examination. It analyzes the rationales and specific implementation strategies of various policies for adding points on the entrance exam, as well as their advantages and pitfalls. Based on these observations and analysis, the author also offers policy recommendations on the…

  5. An Innovative Excel Application to Improve Exam Reliability in Marketing Courses

    ERIC Educational Resources Information Center

    Keller, Christopher M.; Kros, John F.

    2011-01-01

    Measures of survey reliability are commonly addressed in marketing courses. One statistic of reliability is "Cronbach's alpha." This paper presents an application of survey reliability as a reflexive application of multiple-choice exam validation. The application provides an interactive decision support system that incorporates survey item…

  6. Today's Students, Tomorrow's Citizens: Pathways for Learning, Mathematics. Alabama High School Graduation Exam.

    ERIC Educational Resources Information Center

    Alabama State Dept. of Education, Montgomery. Div. of Instructional Services.

    This document is designed to assist classroom teachers in preparing students to successfully complete the Alabama High School Graduation Exam (AHSGE). It consists of activities that are correlated with the Alabama Course of Study: Mathematics, Bulletin 1997, No. 4, and Standards and Objectives (Reading Comprehension, Language, Mathematics, and…

  7. Verbal Final Exam in Introductory Biology Yields Gains in Student Content Knowledge and Longitudinal Performance

    PubMed Central

    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, students who passed the VF outscored their peers on the medical assessment test (MAT), an exam built with 40 Medical College Admissions Test (MCAT) questions (66.4% [n = 160] and 62% [n = 285], respectively; p < 0.001);. The higher-achieving students performed better on MCAT questions in all topic categories tested; the greatest gain occurred on the topic of cellular respiration. Because the VF focused on a conceptually parallel topic, photosynthesis, there may have been authentic knowledge transfer. In longitudinal tracking studies, passing the VF also correlated with higher performance in a range of upper-level science courses, with greatest significance in physiology, biochemistry, and organic chemistry. Participation had a wide range but not equal representation in academic standing, gender, and ethnicity. Yet students nearly unanimously (92%) valued the option. Our findings suggest oral exams at the introductory level may allow instructors to assess and aid students striving to achieve higher-level learning. PMID:24006399

  8. Students' Engagement with a Collaborative Wiki Tool Predicts Enhanced Written Exam Performance

    ERIC Educational Resources Information Center

    Stafford, Tom; Elgueta, Herman; Cameron, Harriet

    2014-01-01

    We introduced voluntary wiki-based exercises to a long-running cognitive psychology course, part of the core curriculum for an undergraduate degree in psychology. Over 2 yearly cohorts, students who used the wiki more also scored higher on the final written exam. Using regression analysis, it is possible to account for students' tendency to…

  9. The TRIPSE: A Process-Oriented Exam for Large Undergraduate Classes

    ERIC Educational Resources Information Center

    Nastos, Stash; Rangachari, P. K.

    2013-01-01

    The TRIPSE (tri-partite problem solving exercise), a process-oriented exam that mimics the scientific process, was used previously in small classes (15-25). Provided limited data, students frame explanations and design experimental tests that they later revise with additional information. Our 6-year experience using it with larger numbers…

  10. An Investigation of Adult Attachment and Coping with Exam-Related Stress

    ERIC Educational Resources Information Center

    Berry, Katherine; Kingswell, Sarah

    2012-01-01

    Students differ in how they cope with and manage stress associated with university life. This study investigates associations between adult attachment and coping strategies for exam-related stress. Fifty-seven students at a university in the north of England completed online questionnaires to assess attachment anxiety and avoidance, helpful and…

  11. University Entrance Exams from the Perspective of Senior High School Students

    ERIC Educational Resources Information Center

    Çirak, Yüksel

    2016-01-01

    The aim of this study was to explore senior high school students' feelings and thoughts about the university entrance exam. A total of 23 senior high school students, 14 girls and 8 boys between the ages of 17 and 18, participated in this qualitative study. Research data were collected between February and March 2015 through face to face…

  12. Multiple-Choice Exams: An Obstacle for Higher-Level Thinking in Introductory Science Classes

    ERIC Educational Resources Information Center

    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…

  13. Practice (Rather than Graded) Quizzes, with Answers, May Increase Introductory Psychology Exam Performance

    ERIC Educational Resources Information Center

    Wickline, Virginia B.; Spektor, Valeriya G.

    2011-01-01

    The authors investigated whether practice (or graded) quizzes, with or without provision of correct answers, would be more beneficial for introductory psychology exam performance. In six sections (N = 249) of an introductory psychology class, taught by the same professor, different approaches to quizzes were applied across sections to measure…

  14. Grading Multiple Choice Exams with Low-Cost and Portable Computer-Vision Techniques

    ERIC Educational Resources Information Center

    Fisteus, Jesus Arias; Pardo, Abelardo; García, Norberto Fernández

    2013-01-01

    Although technology for automatic grading of multiple choice exams has existed for several decades, it is not yet as widely available or affordable as it should be. The main reasons preventing this adoption are the cost and the complexity of the setup procedures. In this paper, "Eyegrade," a system for automatic grading of multiple…

  15. Increasing Student Performance on the Independent School Entrance Exam (ISEE) Using the Gap Analysis Approach

    ERIC Educational Resources Information Center

    Sarshar, Shanon Etty

    2013-01-01

    Using the Gap Analysis problem-solving framework (Clark & Estes, 2008), this study examined the performance gap experienced by 6th grade students on the math sections of the ISEE (Independent School Entrance Exam). The purpose of the study was to identify and validate the knowledge, motivation, and organization causes of the students' low…

  16. The Use of Formative Online Quizzes to Enhance Class Preparation and Scores on Summative Exams

    ERIC Educational Resources Information Center

    Dobson, John L.

    2008-01-01

    Online quizzes were introduced into an undergraduate Exercise Physiology course to encourage students to read ahead and think critically about the course material before coming to class. The purpose of the study was to determine if the use of the online quizzes was associated with improvements in summative exam scores and if the online quizzes…

  17. Shall We Overcome? Self-Efficacy, Teacher Licensure Exams, and African American Preservice Teachers

    ERIC Educational Resources Information Center

    Petchauer, Emery

    2016-01-01

    This article reports findings from a 3-year qualitative study exploring the experiences of African American preservice teachers as they prepared for the Praxis "basic skills" teacher-licensure exam, a gatekeeper to many teacher-education programs. Using the construct of self-efficacy, results illustrate how students assess their Praxis…

  18. USER MANUAL FOR EXPRESS, THE EXAMS-PRZM EXPOSURE SIMULATION SHELL

    EPA Science Inventory

    The Environmental Fate and Effects Division (EFED) of EPA's Office of Pesticide Programs(OPP) uses a suite of ORD simulation models for the exposure analysis portion of regulatory risk assessments. These models (PRZM, EXAMS, AgDisp) are complex, process-based simulation codes tha...

  19. Passing the California High School Exit Exam: Have Recent Policies Improved Student Performance?

    ERIC Educational Resources Information Center

    Betts, Julian R.; Zau, Andrew C.; Zieleniak, Yendrick; Bachofer, Karen Volz

    2012-01-01

    The California High School Exit Examination (CAHSEE) plays an important role in California's public school accountability program. Beginning in grade 10, students have multiple chances to pass the mathematics and English Language Arts components of this exam. If they do not pass both components by the end of grade 12, they will not receive a high…

  20. The Slow Handwriting of Undergraduate Students Constrains Overall Performance in Exam Essays

    ERIC Educational Resources Information Center

    Connelly, Vincent; Dockrell, Julie E.; Barnett, Jo

    2005-01-01

    Undergraduates producing handwritten essays in university exams need to transcribe information onto the page in a rapid and efficient manner under considerable time pressure. In fact, capacity models of the writing process predict that the more automated students can make the transcription process then the more resources will be available for…

  1. Brief Daily Writing Activities and Performance on Major Multiple-Choice Exams

    ERIC Educational Resources Information Center

    Turner, Haley C.; Bliss, Stacy L.; Hautau, Briana; Carroll, Erin; Jaspers, Kathryn E.; Williams, Robert L.

    2006-01-01

    Although past research indicates that giving brief quizzes, administered either regularly or randomly, may lead to improvement in students' performance on major exams, negligible research has targeted daily writing activities that require the processing of course information at a deeper level than might result from simply reading course materials…

  2. Making Sense of Exit Exam Policies: A Phenomenological Study of English Language Development Teachers

    ERIC Educational Resources Information Center

    Forrest, Scott N.

    2010-01-01

    There is a lack of understanding regarding how sensemaking could be incorporated into a professional development program to improve teacher quality and student achievement. The lived experiences of high school English language development teachers as they interpret English language development and one state's high school exit exam instructional…

  3. Individual Oral Exams in Mathematics Courses: 10 Years of Experience at the Air Force Academy

    ERIC Educational Resources Information Center

    Boedigheimer, Ralph; Ghrist, Michelle; Peterson, Dale; Kallemyn, Benjamin

    2015-01-01

    Over the last 10 years faculty members in the Department of Mathematical Sciences at the United States Air Force Academy have incorporated individual oral exams into mathematics courses. We have experimented with various approaches, shared results and ideas with other department members, and refined our techniques. We have found that this…

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

    ERIC Educational Resources Information Center

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

    2012-01-01

    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…

  5. Metacognitive Skills, Academic Success and Exam Anxiety as the Predictors of Psychological Well-Being

    ERIC Educational Resources Information Center

    Isgör, Isa Yücel

    2016-01-01

    The purpose of this research was to investigate the predicting effect of high school students' metacognitive skills, exam anxiety and academic success levels upon their psychological well-being in a provincial center with a medium-scale population in Eastern Anatolian Region. The research group included totally 251 high school students including…

  6. Assessment of Learning Gains Associated with Independent Exam Analysis in Introductory Biology

    PubMed Central

    William, Adrienne E.; Aguilar-Roca, Nancy M.; Tsai, Michelle; Wong, Matthew; Beaupré, Marin Moravec; O’Dowd, Diane K.

    2011-01-01

    This study evaluates the impact of an independent postmidterm question analysis exercise on the ability of students to answer subsequent exam questions on the same topics. It was conducted in three sections (∼400 students/section) of introductory biology. Graded midterms were returned electronically, and each student was assigned a subset of questions answered incorrectly by more than 40% of the class to analyze as homework. The majority of questions were at Bloom's application/analysis level; this exercise therefore emphasized learning at these higher levels of cognition. Students in each section answered final exam questions matched by topic to all homework questions, providing a within-class control group for each question. The percentage of students who correctly answered the matched final exam question was significantly higher (p < 0.05) in the Topic Analysis versus Control Analysis group for seven of 19 questions. We identified two factors that influenced activity effectiveness: 1) similarity in topic emphasis of the midterm–final exam question pair and 2) quality of the completed analysis homework. Our data suggest that this easy-to-implement exercise will be useful in large-enrollment classes to help students develop self-regulated learning skills. Additional strategies to help introductory students gain a broader understanding of topic areas are discussed. PMID:22135369

  7. Potential Danger in Pre-Populating Exam Note Sheets with Formulas

    ERIC Educational Resources Information Center

    McCaskey, Timothy L.

    2015-01-01

    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…

  8. Teacher-Generated Final Exams in High School Science: Content, Rigor, and Assessment Literacy

    NASA Astrophysics Data System (ADS)

    Lach, Michael

    This study investigates a large collection of teacher-generated end-of-semester final exams from Chicago Public School high school science classrooms in order to explore the depth and breadth of content that students learn in science classrooms. Teachers focus on a specific set of scientific content that is driven by district guidelines and popular textbooks but not particularly aligned to standards. To most teachers, rigor means coverage instead of intellectual press. The assessments, while unsophisticated, seem to be delivering what is expected of them---a way to mimic the most basic format of the ACT exam quickly. There was little variation among high poverty and low poverty schools, matching national data and indicating issues that are more due to a particular culture of science teaching and learning than driven by particular contexts. The study identifies implications for the observed homogeneity of final exam rigor and content, identifies gaps between how the routine of final exams are design and implemented in schools, and discusses similar methodological efforts that could enhance the ability of schools and districts to access useful information about the technical core of instruction.

  9. Assessment of Learning Gains Associated with Independent Exam Analysis in Introductory Biology

    ERIC Educational Resources Information Center

    Williams, Adrienne E.; Aguilar-Roca, Nancy M.; Tsai, Michelle; Wong, Matthew; Beaupre, Marin Moravec; O'Dowd, Diane K.

    2011-01-01

    This study evaluates the impact of an independent postmidterm question analysis exercise on the ability of students to answer subsequent exam questions on the same topics. It was conducted in three sections (~400 students/section) of introductory biology. Graded midterms were returned electronically, and each student was assigned a subset of…

  10. The Grass Isn’t Always Greener: Perceptions of and Performance on Open-Note Exams

    PubMed Central

    Sato, Brian K.; He, Wenliang; Warschauer, Mark; Kadandale, Pavan

    2015-01-01

    Undergraduate biology education is often viewed as being focused on memorization rather than development of students’ critical-thinking abilities. We speculated that open-note testing would be an easily implemented change that would emphasize higher-order thinking. As open-note testing is not commonly used in the biological sciences and the literature on its effects in biology education is sparse, we performed a comprehensive analysis of this intervention on a primary literature–based exam across three large-enrollment laboratory courses. Although students believed open-note testing would impact exam scores, we found no effect on performance, either overall or on questions of nearly all Bloom’s levels. Open-note testing also produced no advantage when examined under a variety of parameters, including research experience, grade point average, course grade, prior exposure to primary literature–focused laboratory courses, or gender. Interestingly, we did observe small differences in open- and closed-note exam performance and perception for students who experienced open-note exams for an entire quarter. This implies that student preparation or in-test behavior can be altered by exposure to open-note testing conditions in a single course and that ­increased experience may be necessary to truly understand the impact of this intervention. PMID:25828402

  11. Indiana Teachers' Perspectives on Testing Accommodations for Limited English Proficient Students Taking the Graduation Qualifying Exam

    ERIC Educational Resources Information Center

    Hetler, Angela Dawn

    2010-01-01

    This qualitative case study examines teachers' perspectives on testing accommodations for Limited English Proficient (LEP) students taking Indiana's Graduation Qualifying Exam (GQE). The Indiana Department of Education (IDOE) states that the purpose of testing accommodations is to "level the playing field" between LEP students and their non-LEP…

  12. The Relationship of Academic Self-Efficacy to Class Participation and Exam Performance

    ERIC Educational Resources Information Center

    Galyon, Charles E.; Blondin, Carolyn A.; Yaw, Jared S.; Nalls, Meagan L.; Williams, Robert L.

    2012-01-01

    This study examined the relationship of academic self-efficacy to engagement in class discussion and performance on major course exams among students (N = 165) in an undergraduate human development course. Cluster analysis was used to identify three levels of academic self-efficacy: high (n = 34), medium (n = 91), and low (n = 40). Results…

  13. Alabama High School Graduation Exam Outcomes: Agricultural Education and Its Impact

    ERIC Educational Resources Information Center

    Nolin, Joshua Brock

    2011-01-01

    This study sought to determine if there is possible a relationship between agricultural education class credits obtained by students and their subsequent outcome on the Alabama High School Graduation Exam (AHSGE). Also, the perceptions of Alabama agricultural educators regarding 1) student test taking preparation 2) academic standard integration…

  14. Validating Performance Level Descriptors (PLDs) for the AP® Environmental Science Exam

    ERIC Educational Resources Information Center

    Reshetar, Rosemary; Kaliski, Pamela; Chajewski, Michael; Lionberger, Karen

    2012-01-01

    This presentation summarizes a pilot study conducted after the May 2011 administration of the AP Environmental Science Exam. The study used analytical methods based on scaled anchoring as input to a Performance Level Descriptor validation process that solicited systematic input from subject matter experts.

  15. Gender Gap Trends on Mathematics Exams Position Girls and Young Women for STEM Careers

    ERIC Educational Resources Information Center

    Beekman, John A.; Ober, David

    2015-01-01

    Nine years of results on 4.2 million of Indiana's Indiana Statewide Testing for Educational Progress (ISTEP) mathematics (math) exams (grades 3-10) taken after the implementation of No Child Left Behind have been used to determine gender gaps and their associated trends. Sociocultural factors were investigated by comparing math gender gaps…

  16. Class of 2012 Advanced Placement and International Baccalaureate Exam Participation and Performance. Memorandum

    ERIC Educational Resources Information Center

    Marks, Susan F.

    2013-01-01

    Students in the Montgomery County (Maryland) Public Schools (MCPS) Class of 2012 continued to outperform Maryland and the nation on Advanced Placement (AP) examinations based on the "AP Report to the Nation" released by the College Board on February 20, 2013. In 2012, 67.3 percent of MCPS graduates took one or more AP exams. A striking…

  17. Past, Present, and Future of AP Chemistry: A Brief History of Course and Exam Alignment Efforts

    ERIC Educational Resources Information Center

    Magrogan, Serena

    2014-01-01

    As part of the Advanced Placement (AP) Program's commitment to continually enhance alignment with current best practices in college-level learning, the AP Program is currently evaluating and redesigning courses and exams, one of which launched during the 2013-2014 academic school year: AP chemistry. The history of the AP chemistry course and…

  18. Examining the Role of Advanced Placement[R] Exam Participation in 4-Year College Enrollment

    ERIC Educational Resources Information Center

    Chajewski, Michael; Mattern, Krista D.; Shaw, Emily J.

    2011-01-01

    The purpose of the current study was to examine the relationship between Advanced Placement (AP) exam participation and enrollment in a 4-year postsecondary institution. A positive relationship was expected given that the primary purpose of offering AP courses is to allow students to engage in college-level academic work while in high school, and…

  19. Designing Chemistry Practice Exams for Enhanced Benefits: An Instrument for Comparing Performance and Mental Effort Measures

    ERIC Educational Resources Information Center

    Knaus, Karen J.; Murphy, Kristen L.; Holme, Thomas A.

    2009-01-01

    The design and use of a chemistry practice exam instrument that includes a measure for student mental effort is described in this paper. Use of such an instrument can beneficial to chemistry students and chemistry educators as well as chemical education researchers from both a content and cognitive science perspective. The method for calculating…

  20. Do High-Stakes Placement Exams Predict College Success? CCRC Working Paper No. 41

    ERIC Educational Resources Information Center

    Scott-Clayton, Judith

    2012-01-01

    Community colleges are typically assumed to be nonselective, open-access institutions. Yet access to college-level courses at such institutions is far from guaranteed: the vast majority of two-year institutions administer high-stakes exams to entering students that determine their placement into either college-level or remedial education. Despite…

  1. Let Your Students Set the Curve with a Cooperative Exam Critique.

    ERIC Educational Resources Information Center

    Cottell, Philip G., Jr.

    2000-01-01

    Asserting that cooperative learning offers faculty the means to turn a tepid examination review and critique into a highly energized, active student learning experience, this paper describes a cooperative learning structure for an exam critique that motivates students to exercise their critical thinking skills and engage in deeper learning. (EV)

  2. Cheating or Cheated? Surviving Secondary Exit Exams in a Neoliberal Era

    ERIC Educational Resources Information Center

    Buckner, Elizabeth; Hodges, Rebecca

    2016-01-01

    Cheating on exams is a rampant and highly developed practice among youth in the Arab world, often involving elaborate networks, advanced technology and adult authorities. Rather than viewing cheating as mere laziness or immorality, this article interrogates the social meanings of cheating by comparing the practices and discourses of cheating on…

  3. Detection and Evaluation of Cheating on College Exams Using Supervised Classification

    ERIC Educational Resources Information Center

    Cavalcanti, Elmano Ramalho; Pires, Carlos Eduardo; Cavalcanti, Elmano Pontes; Pires, Vládia Freire

    2012-01-01

    Text mining has been used for various purposes, such as document classification and extraction of domain-specific information from text. In this paper we present a study in which text mining methodology and algorithms were properly employed for academic dishonesty (cheating) detection and evaluation on open-ended college exams, based on document…

  4. What Do You Do When a Student Cheats on an Exam?

    ERIC Educational Resources Information Center

    NEA Today, 2002

    2002-01-01

    Describes actions teachers have taken when they caught students cheating on tests, including: giving the students a zero with no chance to re-take the exam, telling the parents about the incident, taking the students aside and explaining how serious cheating could be later in life, and making the students write home explaining what they did (and…

  5. Class of 2014 Advanced Placement and International Baccalaureate Exam Participation and Performance. Memorandum

    ERIC Educational Resources Information Center

    Sanderson, Geoffrey T.

    2015-01-01

    Beginning in 2006, Maryland has led the nation as the state with the highest percentage of graduates who earned one or more Advanced Placement (AP) exam scores of 3 or higher. Students in the Montgomery County (Maryland) Public Schools (MCPS) Class of 2014 continued to outperform students in the state of Maryland on AP examinations based on AP…

  6. Class of 2013 Advanced Placement and International Baccalaureate Exam Participation and Performance. Memorandum

    ERIC Educational Resources Information Center

    Sanderson, Geoffrey T.

    2014-01-01

    Beginning in 2006, Maryland has led the nation as the state with the highest percentage of graduates who earned one or more Advanced Placement (AP) exam scores of 3 or higher. Students in the Montgomery County Public Schools (MCPS) Class of 2013 continued to outperform students in the state of Maryland and the nation on AP examinations, based on…

  7. The Scare Tactic: Do Fear Appeals Predict Motivation and Exam Scores?

    ERIC Educational Resources Information Center

    Putwain, David; Remedios, Richard

    2014-01-01

    Prior to high-stakes exams, teachers use persuasive messages that highlight to students the possible consequences of failure. Such messages are known as fear appeals. This study examined whether fear appeals relate to self- and non-self-determined motivation and academic performance. Data were collected in 3 waves. Self-report data pertaining to…

  8. Student Performance Shows Slight Improvement when Open Notes Are Used during Information Systems Exams

    ERIC Educational Resources Information Center

    Duncan, Doris G.

    2007-01-01

    Students often ask about the use of reference aids during exams in most disciplines. These aids are most commonly notes they have taken, textbooks, handouts, or perhaps access to information stored on computers and/or the Internet. Although the practice of using reference aids may be common, the author was unable to locate much relevant research…

  9. Be a Professional - Be Licensed! - Take the agricultural engineering professional engineering exam

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Between October 2005 and October 2007, only 78 Agricultural Engineers took the professional engineering (PE) exam in the field of Agricultural Engineering, while the other 406 registered Agricultural Engineering Examinees took tests offer by other engineering disciplines. With the decline in partic...

  10. Trainee Teachers' Conceptions of Teaching and Learning, Classroom Layout and Exam Design

    ERIC Educational Resources Information Center

    Betoret, Fernando Domenech; Artiga, Amparo Gomez

    2004-01-01

    The objective of this study centres on identifying and classifying the conceptions of teaching and learning held by future secondary school teachers, and on analysing the relationship between these conceptions and the way classroom space is organized and exams are designed. The test instruments used were applied to a sample of 138 graduates, who…

  11. Examining Validity in a Performance Test: The Listening Summary Translation Exam (LSTE)--Spanish Version.

    ERIC Educational Resources Information Center

    Scott, Mary Lee; And Others

    1996-01-01

    Reports on a project to develop and validate a criterion-referenced performance test of listening summary translation ability. This exam is designed to assess ability to comprehend and summarize in written English recorded conversations spoken in Spanish. The Bachman framework is used to present the test and provide evidence for its validity. (12…

  12. The Validity Argument of a Web-Based Spanish Listening Exam: Test Usefulness Evaluation

    ERIC Educational Resources Information Center

    Pardo-Ballester, Cristina

    2010-01-01

    This study describes research used for supporting a validity argument for a new Spanish Listening Exam, whose scores are intended to place examinees into appropriate levels of university Spanish classes. This study contributes to the field of argument-based approaches to language assessment by implementing Bachman's (2005) assessment use argument…

  13. Research and Teaching: Midterm and First-Exam Grades Predict Final Grades in Biology Courses

    ERIC Educational Resources Information Center

    Jensen, Philip A.; Barron, James N.

    2014-01-01

    Students routinely ignore negative feedback regarding their performances early in college science courses. In this study we analyzed the extent to which two standard forms of feedback, midterm and first-exam grades, correlated with final grades in several biology courses. The courses ranged from an introductory course for nonmajors to upper…

  14. The Evolution of Foreign Language AP Exam Candidates: A 36-Year Descriptive Study

    ERIC Educational Resources Information Center

    Brown, Alan V.; Thompson, Gregory L.

    2016-01-01

    Using a data set exclusively prepared for and licensed to them by the College Board, the authors examined the growth of the Advanced Placement program in foreign languages and overall trends in regard to the number of candidates who sat for the foreign language exams, their gender, their scores, and their ethnicity over the 36-year period covering…

  15. Examination of the Classification Accuracy of Music Education Special Aptitude Exams

    ERIC Educational Resources Information Center

    Atar, Hakan Yavuz; Sayin, Ayfer; Atar, Burcu

    2013-01-01

    It is critical both for candidates who apply for programs that require special aptitude and the professors who teach in these programs whether those students' scores on placement exams are correctly calculated. Because student's ability profile and the quality of education in these programs may be directly affected by how candidates…

  16. Awarding Credit Where Credit Is Due: Effective Practices for the Implementation of Credit by Exam. Adopted Spring 2014

    ERIC Educational Resources Information Center

    Academic Senate for California Community Colleges, 2014

    2014-01-01

    Credit by Exam is a mechanism employed in the California community colleges as a means of granting credit for student learning outside of the traditional classroom. In some instances, credit by exam is the means used to award college credit for structured learning experiences in a secondary educational setting, while in other instances knowledge…

  17. 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... Practitioner Engagement Project Committee will be held Wednesday, June 22, 2011, at 9 a.m. Pacific Time...

  18. 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... Practitioner Engagement Project Committee will be held Wednesday, April 27, 2011, at 9 a.m., Pacific Time...

  19. 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... Practitioner Engagement Project Committee will be held Wednesday, September 28, 2011, at 9 a.m. Pacific...

  20. 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... Practitioner Engagement Project Committee will be held Wednesday, October 26, 2011, at 9 a.m. Pacific Time...

  1. 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... Practitioner Engagement Project Committee will be held Tuesday, August 2, 2011, at 9 a.m. Pacific Time...

  2. 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... Practitioner Engagement Project Committee will be held Wednesday, November 23, 2011, at 9 a.m. Pacific Time...

  3. 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... Practitioner Engagement Project Committee will be held Wednesday, March 23, 2011, at 9 a.m., Pacific Time...

  4. "Too Complex for Me!" Why Do Performance-Approach and Performance-Avoidance Goals Predict Exam Performance?

    ERIC Educational Resources Information Center

    Darnon, Celine; Butera, Fabrizio; Mugny, Gabriel; Quiamzade, Alain; Hulleman, Chris S.

    2009-01-01

    Classroom research on achievement goals has revealed that performance-approach goals (goals to outperform others) positively predict exam performance whereas performance-avoidance goals (goals not to perform more poorly than others) negatively predict it. Because prior classroom research has primarily utilized multiple-choice exam performance, the…

  5. Keeping up with the Standards: What One English Professor Learned from Taking Every Standardized Exam in His Discipline

    ERIC Educational Resources Information Center

    Brown, Kevin

    2015-01-01

    In this article, the author describes his project to take every standardized exam English majors students take. During the summer and fall semesters of 2012, the author signed up for and took the GRE General Test, the Praxis Content Area Exam (English Language, Literature, and Composition: Content Knowledge), the Senior Major Field Tests in…

  6. Cheat Sheet or Open-Book? A Comparison of the Effects of Exam Types on Performance, Retention, and Anxiety

    ERIC Educational Resources Information Center

    Gharib, Afshin; Phillips, William; Mathew, Noelle

    2012-01-01

    The differences between open-book, cheat sheet, and closed-book exams were examined in two different types of psychology courses. A total of 297 students enrolled in eight sections of Introductory Psychology and 99 students enrolled in four sections of Statistics participated in this study. Exam types were counterbalanced across sections of the…

  7. 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

    ... Internal Revenue Service Open Meeting of the Taxpayer Advocacy Panel Small Business/Self Employed...: 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...

  8. Payment of Advanced Placement Exam Fees by Virginia Public School Divisions and Its Impact on Advanced Placement Enrollment and Scores

    ERIC Educational Resources Information Center

    Cirillo, Mary Grupe

    2010-01-01

    The purpose of this study was to determine the impact of Virginia school divisions' policy of paying the fee for students to take Advanced Placement exams on Advanced Placement course enrollment, the number of Advanced Placement exams taken by students, the average scores earned and the percent of students earning qualifying scores of 3, 4, or 5…

  9. WA State Profile. Washington: Washington Assessment of Student Learning (WASL) and the New High School Proficiency Exam (HSPE)

    ERIC Educational Resources Information Center

    Center on Education Policy, 2010

    2010-01-01

    This paper provides information about Washington Assessment of Student Learning and the new High School Proficiency Exam. 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 and postsecondary education; (2) Determine prospective high school…

  10. So Many Choices, So Little Time: Strategies for Understanding and Taking Multiple-Choice Exams in History

    ERIC Educational Resources Information Center

    Blackey, Robert

    2009-01-01

    Learning as much as possible about what to expect and how best to select among response choices enables students to improve their scores so as to reflect more fully their knowledge and abilities, whether taking the SAT, ACT, AP history exams, multiple-choice exams in college courses, the GRE, or any other standardized examinations that include…

  11. Teaching to the Test…or Testing to Teach: Exams Requiring Higher Order Thinking Skills Encourage Greater Conceptual Understanding

    ERIC Educational Resources Information Center

    Jensen, Jamie L.; McDaniel, Mark A.; Woodard, Steven M.; Kummer, Tyler A.

    2014-01-01

    In order to test the effect of exam-question level on fostering student conceptual understanding, low-level and high-level quizzes and exams were administered in two sections of an introductory biology course. Each section was taught in a high-level inquiry based style but was assigned either low-level questions (memory oriented) on the quizzes…

  12. 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…

  13. 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.

  14. Reserves in western basins

    SciTech Connect

    Caldwell, R.H.; Cotton, B.W.

    1995-04-01

    The objective of this project is to investigate the reserves potential of tight gas reservoirs in three Rocky Mountain basins: the Greater Green River (GGRB), Uinta and Piceance basins. The basins contain vast gas resources that have been estimated in the thousands of Tcf hosted in low permeability clastic reservoirs. This study documents the productive characteristics of these tight reservoirs, requantifies gas in place resources, and characterizes the reserves potential of each basin. The purpose of this work is to promote understanding of the resource and to encourage its exploitation by private industry. At this point in time, the GGRB work has been completed and a final report published. Work is well underway in the Uinta and Piceance basins which are being handled concurrently, with reports on these basins being scheduled for the middle of this year. Since the GGRB portion of the project has been completed, this presentation win focus upon that basin. A key conclusion of this study was the subdivision of the resource, based upon economic and technological considerations, into groupings that have distinct properties with regard to potential for future producibility, economics and risk profile.

  15. China's petroleum reserves

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    Perhaps because of declining yields inland, the People's Republic of China has moved to its storm-ridden coast to develop additional petroleum reserves. During 1979 and 1980, 44 foreign oil-exploration companies engaged in what has been termed the world's record “seismic shoot” over 411,000 km2 extending from the Yellow Sea through the South China Sea, and including Beibu Wan (Gulf of Tonkin), the bay lying east of Hanoi and west of Hainan Island. These offshore oil reserves are estimated to be 40-100 billion barrels.The seas off the mainland are relatively shallow (most drilling has been done in less than 100 m) but they are stormy. According to a recent description, “Typhoons can … occur in the area at almost any time of the year, and the strong winds (160 km h-1 or more) which they generate frequently wreak havoc in the Philippines, Vietnam, China, and occasionally, Hong Kong. Typhoon Vera, which hit southern China in late July, did immense damage and claimed dozens of lives. The main implications for oil operation naturally relate to rig design and safety measures but onshore facilities will also have to be designed accordingly” (New Scientist, Sept. 8, 1983).

  16. 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…

  17. 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…

  18. 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.

  19. Electronic reserves: copyright and permissions

    PubMed Central

    Graves, Karen 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

  20. Exploring the Use of Statewide Exit Exams to Spread Innovation--The Example of "Context" in Science Tasks from an International Comparative Perspective

    ERIC Educational Resources Information Center

    Kuhn, Svenja Mareike

    2011-01-01

    Many innovation-oriented concepts have recently been discussed as means to improve science education and instruction as well as the corresponding tests and exit exams. So far, empirical evidence of whether these new concepts for exam tasks actually find their way into the exam practice is still pending. This contribution takes up this desideratum…

  1. Using College Placement Exams as Early Signals of College Readiness: An Examination of California's Early Assessment Program and New York's At Home in College Program

    ERIC Educational Resources Information Center

    Venezia, Andrea; Voloch, Daniel

    2012-01-01

    A promising strategy for promoting successful college transition and increasing college completion rates is to help students avoid developmental coursework by preparing them for placement exams before they enroll in college. A lack of content alignment between high school exit exams and college entrance exams is one of many troubling disconnects…

  2. Advanced Placement[R] Exam-Taking and Performance: Relationships with First-Year Subject Area College Grades. Research Report 2011-4

    ERIC Educational Resources Information Center

    Patterson, Brian F.; Packman, Sheryl; Kobrin, Jennifer L.

    2011-01-01

    The purpose of this study was to examine the effects of Advanced Placement[R] (AP[R]) exam participation and performance on college grades for courses taken in the same subject area as students' AP Exam(s). Students' first-year college subject area grade point averages (SGPAs) were examined in nine subject areas: mathematics, computer science,…

  3. Advanced Placement® Exam-Taking and Performance: Relationships with First-Year Subject Area College Grades. Research Report No. 2011-4

    ERIC Educational Resources Information Center

    Patterson, Brian F.; Packman, Sheryl; Kobrin, Jennifer L.

    2011-01-01

    The purpose of this study was to examine the effects of Advanced Placement (AP) exam participation and performance on college grades for courses taken in the same subject area as students' AP Exam(s). Students' first-year college subject area grade point averages (SGPAs) were examined in nine subject areas: mathematics, computer science,…

  4. An MLC-based version for the ecliptic method for the determination of backscatter into the beam monitor chambers in photon beams of medical accelerators.

    PubMed

    Nelli, Flavio Enrico

    2016-03-01

    A very simple method to measure the effect of the backscatter from secondary collimators into the beam monitor chambers in linear accelerators equipped with multi-leaf collimators (MLC) is presented here. The backscatter to the monitor chambers from the upper jaws of the secondary collimator was measured on three beam-matched linacs by means of three methods: this new methodology, the ecliptic method, and assessing the variation of the beam-on time per monitor unit with dose rate feedback disabled. This new methodology was used to assess the backscatter characteristics of asymmetric over-traveling jaws. Excellent agreement between the backscatter values measured using the new methodology introduced here and the ones obtained using the other two methods was established. The experimental values reported here differ by less than 1% from published data. The sensitivity of this novel technique allowed differences in backscatter due to the same opening of the jaws, when placed at different positions on the beam path, to be resolved. The introduction of the ecliptic method has made the determination of the backscatter to the monitor chambers an easy procedure. The method presented here for machines equipped with MLCs makes the determination of backscatter to the beam monitor chambers even easier, and suitable to characterize linacs equipped with over-traveling asymmetric secondary collimators. This experimental procedure could be simply implemented to fully characterize the backscatter output factor constituent when detailed dosimetric modeling of the machine's head is required. The methodology proved to be uncomplicated, accurate and suitable for clinical or experimental environments. PMID:26671445

  5. Barriers to creating a more culturally diverse nursing profession. Linguistic bias in multiple-choice nursing exams.

    PubMed

    Bosher, Susan

    2003-01-01

    As part of a grant to recruit and retain multicultural and economically disadvantaged nursing students, funding was approved for a study analyzing multiple-choice nursing course exams for linguistic and cultural bias. Nineteen exams, for a total of 673 multiple-choice test items, were analyzed for this study. The categories of analysis used to identify flaws in the test items were: testwise flaws, irrelevant difficulty in stem, irrelevant difficulty in option, linguistic/structural bias, and cultural bias. Twenty-eight types of flaws occurred at least 10 times in the reviewed exams. Flaws from each of the categories are presented and discussed; specific examples are analyzed and revised. PMID:12674918

  6. Strategic Petroleum Reserve quarterly report

    SciTech Connect

    1995-11-15

    The Strategic Petroleum Reserve was created pursuant to the Energy Policy and Conservation Act of December 22, 1975 (Public Law 94-163). Its purposes are to reduce the impact of disruptions in supplies of petroleum products and to carry out obligations of the United States under the Agreement on an International Energy Program. Section 165(a) of the Act requires the submission of Annual Reports and Section 165(b)(1) requires the submission of Quarterly Reports. This Quarterly Report highlights activities undertaken during the third quarter of calendar year 1995, including: inventory of petroleum products stored in the Reserve; current storage capacity and ullage available; current status of the Strategic Petroleum Reserve storage facilities, major projects and the acquisition of petroleum products; funds obligated by the Secretary from the SPR Petroleum Account and the Strategic Petroleum Reserve Account during the prior calendar quarter and in total; and major environmental actions completed, in progress, or anticipated.

  7. Reserves, resilience and dynamic landscapes.

    PubMed

    Bengtsson, Janne; Angelstam, Per; Elmqvist, Thomas; Emanuelsson, Urban; Folke, Carl; Ihse, Margareta; Moberg, Fredrik; Nyström, Magnus

    2003-09-01

    In a world increasingly modified by human activities, the conservation of biodiversity is essential as insurance to maintain resilient ecosystems and ensure a sustainable flow of ecosystem goods and services to society. However, existing reserves and national parks are unlikely to incorporate the long-term and large-scale dynamics of ecosystems. Hence, conservation strategies have to actively incorporate the large areas of land that are managed for human use. For ecosystems to reorganize after large-scale natural and human-induced disturbances, spatial resilience in the form of ecological memory is a prerequisite. The ecological memory is composed of the species, interactions and structures that make ecosystem reorganization possible, and its components may be found within disturbed patches as well in the surrounding landscape. Present static reserves should be complemented with dynamic reserves, such as ecological fallows and dynamic successional reserves, that are part of ecosystem management mimicking natural disturbance regimes at the landscape level.

  8. US gas reserves show gain

    SciTech Connect

    Not Available

    1991-09-16

    This paper reports that the Energy Information Administration reports 1990 U.S. natural gas reserves increased for the first time since 1981. Reserves inched up 1.3% to 169.346 tcf, largely because of coalbed methane development. Gas reserves in Alaska and the Lower 48 not only increased, but the latter are higher than they were in 1985. Gas discoveries increased 23.3% and totaled 12.368 tcf in 1990. Major finds were drilled in New Mexico, in Alabama state water, and off Louisiana. Crude oil reserves dropped less than 1% to 26.254 billion bbl, close to the average decline of 1.2%/year for the past decade. Crude oil discoveries were 20% less than the annual average for the past decade.

  9. Oil and gas reserves estimates

    USGS Publications Warehouse

    Harrell, R.; Gajdica, R.; Elliot, D.; Ahlbrandt, T.S.; Khurana, S.

    2005-01-01

    This article is a summary of a panel session at the 2005 Offshore Technology Conference. Oil and gas reserves estimates are further complicated with the expanding importance of the worldwide deepwater arena. These deepwater reserves can be analyzed, interpreted, and conveyed in a consistent, reliable way to investors and other stakeholders. Continually improving technologies can lead to improved estimates of production and reserves, but the estimates are not necessarily recognized by regulatory authorities as an indicator of "reasonable certainty," a term used since 1964 to describe proved reserves in several venues. Solutions are being debated in the industry to arrive at a reporting mechanism that generates consistency and at the same time leads to useful parameters in assessing a company's value without compromising confidentiality. Copyright 2005 Offshore Technology Conference.

  10. Reserves, resilience and dynamic landscapes.

    PubMed

    Bengtsson, Janne; Angelstam, Per; Elmqvist, Thomas; Emanuelsson, Urban; Folke, Carl; Ihse, Margareta; Moberg, Fredrik; Nyström, Magnus

    2003-09-01

    In a world increasingly modified by human activities, the conservation of biodiversity is essential as insurance to maintain resilient ecosystems and ensure a sustainable flow of ecosystem goods and services to society. However, existing reserves and national parks are unlikely to incorporate the long-term and large-scale dynamics of ecosystems. Hence, conservation strategies have to actively incorporate the large areas of land that are managed for human use. For ecosystems to reorganize after large-scale natural and human-induced disturbances, spatial resilience in the form of ecological memory is a prerequisite. The ecological memory is composed of the species, interactions and structures that make ecosystem reorganization possible, and its components may be found within disturbed patches as well in the surrounding landscape. Present static reserves should be complemented with dynamic reserves, such as ecological fallows and dynamic successional reserves, that are part of ecosystem management mimicking natural disturbance regimes at the landscape level. PMID:14627367

  11. SU-E-E-02: An Excel-Based Study Tool for ABR-Style Exams

    SciTech Connect

    Cline, K; Stanley, D; Defoor, D; Stathakis, S; Gutierrez, A; Papanikolaou, N; Kirby, N

    2015-06-15

    Purpose: As the landscape of learning and testing shifts toward a computer-based environment, a replacement for paper-based methods of studying is desirable. Using Microsoft Excel, a study tool was developed that allows the user to populate multiple-choice questions and then generate an interactive quiz session to answer them. Methods: The code for the tool was written using Microsoft Excel Visual Basic for Applications with the intent that this tool could be implemented by any institution with Excel. The base tool is a template with a setup macro, which builds out the structure based on user’s input. Once the framework is built, the user can input sets of multiple-choice questions, answer choices, and even add figures. The tool can be run in random-question or sequential-question mode for single or multiple courses of study. The interactive session allows the user to select answer choices and immediate feedback is provided. Once the user is finished studying, the tool records the day’s progress by reporting progress statistics useful for trending. Results: Six doctoral students at UTHSCSA have used this tool for the past two months to study for their qualifying exam, which is similar in format and content to the American Board of Radiology (ABR) Therapeutic Part II exam. The students collaborated to create a repository of questions, met weekly to go over these questions, and then used the tool to prepare for their exam. Conclusion: The study tool has provided an effective and efficient way for students to collaborate and be held accountable for exam preparation. The ease of use and familiarity of Excel are important factors for the tool’s use. There are software packages to create similar question banks, but this study tool has no additional cost for those that already have Excel. The study tool will be made openly available.

  12. Guidance Regarding Sample Collection and Refinement of Fecal Flotation Exam for the Isolation of Aspiculuris tetraptera.

    PubMed

    Goodroe, Anna E; Baxter, Victoria K; Watson, Julie

    2016-01-01

    Aspiculuris tetraptera continues to be a problem in rodent vivaria, in part due to difficulties in parasite detection. Although PCR testing is highly sensitive, it is expensive and does not always provide immediate results. Consequently, many institutions rely on passive fecal flotation as a quick inhouse exam for diagnosing A. tetraptera infections. To increase the sensitivity of this test, we examined multiple parameters to determine the optimal test protocol. A 30-min soaking period prior to fecal flotation for 15 min allowed fecal pellets to soften and facilitated efficient egg isolation. We also evaluated the effect of time of day, sample size, age, sex, and housing status on egg isolation. No evidence of cyclical egg shedding was found, and although larger fecal sample sizes did not result in more eggs isolated, their use reduced the incidence of false-negative exams. The most eggs were isolated from 8- and 12-wk-old mice, and as mice aged, the number of eggs isolated declined. Overall, neither sex nor housing status influenced the number of eggs isolated. Finally, examination of multiple diagnostic tests (fecal flotation exam, direct examination of cecal and colonic contents, and fecal PCR) revealed that no single test was definitive, thus indicating that multiple tests might be required to successfully screen mice with low pinworm burdens. These findings provide guidance regarding sample selection, collection, and processing to efficiently detect A. tetraptera. PMID:27657708

  13. A Novel Restraining Device for Small Animal Imaging Exams: Validation in Rabbits

    PubMed Central

    Barbosa, Carlos Henrique; Carvalho, Antonio Carlos; de Souza, Sérgio; Machado, Fernanda; Guedes, Fábio; Monteiro, André; Schanaider, Alberto

    2015-01-01

    Objective. To develop, validate, and patent a Restraining Device for Small Animal Imaging Exams (RDSAIE) that allows exams to be comfortably conducted without risks to animals and professionals. Methods. A RDSAIE with a mobile cover and shelf was built with transparent acrylic material. A total of six anesthetized rabbits were used to perform the following imaging exams of the skull: Cone Beam Computed Tomography, Magnetic Resonance Imaging, and Scintigraphy. Results. The device showed great functionality and full visibility of the animal behavior, which remained fully stabilized and immobilized in either the horizontal or vertical position without the need for a person to remain in the test room to assist them. The procedures were performed without difficulty, and images of good resolution and without artifacts were obtained. Conclusion. The RDSAIE is comfortable, safe, efficient, and ergonomic. It allows the easy placement of animals in different body positions, including the vertical, the maintenance of postural stability, and full visibility. It may be constructed for animals heavier than 4 kg and it is adaptable for translational studies in anima nobile. PMID:26114109

  14. Healthy lifestyles and access to periodic health exams among Brazilian women.

    PubMed

    Leal, Maria do Carmo; Gama, Silvana Granado Nogueira da; Frias, Paulo; Szwarcwald, Célia Landmann

    2005-01-01

    Using data from the World Health Survey carried out in Brazil in 2003, this paper has the objective of describing the sociodemographic profile of Brazilian women (age 18-69 years of age) that have adequate health care, not only with respect to health service utilization but also to healthy lifestyles. Sociodemographic variables (age, marital status, race, education level, number of household assets, and occupation), health care variables (periodic gynecologic exam with Papanicolaou, mammography among women aged 40-69 years, body mass index, smoking, alcohol, physical activity, dental care, private health insurance), and self-rated health were analyzed by municipality size strata. Logistic regression models were used to identify the characteristics of women that have adequate health care. Coverage of periodic gynecologic exam with Papanicolaou was 65.0% and mammography coverage was 47.0%. Less than 20.0% of Brazilian women have adequate care, and the most associated factors were: being younger than 40 years old, having higher educational level, having private health insurance and being married. The results indicate the need to develop health promotion policies focused on modifying the risk habits and risk practices to health, and to stimulate preventive periodic health exams.

  15. Do racial and ethnic group differences in performance on the MCAT exam reflect test bias?

    PubMed

    Davis, Dwight; Dorsey, J Kevin; Franks, Ronald D; Sackett, Paul R; Searcy, Cynthia A; Zhao, Xiaohui

    2013-05-01

    The Medical College Admission Test (MCAT) is a standardized examination that assesses fundamental knowledge of scientific concepts, critical reasoning ability, and written communication skills. Medical school admission officers use MCAT scores, along with other measures of academic preparation and personal attributes, to select the applicants they consider the most likely to succeed in medical school. In 2008-2011, the committee charged with conducting a comprehensive review of the MCAT exam examined four issues: (1) whether racial and ethnic groups differ in mean MCAT scores, (2) whether any score differences are due to test bias, (3) how group differences may be explained, and (4) whether the MCAT exam is a barrier to medical school admission for black or Latino applicants. This analysis showed that black and Latino examinees' mean MCAT scores are lower than white examinees', mirroring differences on other standardized admission tests and in the average undergraduate grades of medical school applicants. However, there was no evidence that the MCAT exam is biased against black and Latino applicants as determined by their subsequent performance on selected medical school performance indicators. Among other factors which could contribute to mean differences in MCAT performance, whites, blacks, and Latinos interested in medicine differ with respect to parents' education and income. Admission data indicate that admission committees accept majority and minority applicants at similar rates, which suggests that medical students are selected on the basis of a combination of attributes and competencies rather than on MCAT scores alone.

  16. Strategic Petroleum Reserve quarterly report

    SciTech Connect

    Not Available

    1992-08-15

    The Strategic Petroleum Reserve (SPR) was created pursuant to the Energy Policy and Conservation Act (EPCA) Public Law 94-163, approved on December 22, 1975, and extended in July 1985, June 1989, March 1990, and September 1990, to reduce the impact of disroptions in petroleum supplies and to carry out obligations of the United States under the Agreement on an International Energy Program. The Strategic Petroleum Reserve Quarterly Report is submitted in accordance with section 165(b) of the Energy Policy and Conservation Act, as amended, which requires that the Secretary of Energy submit quarterly reports to Congress on activities undertaken with respect to the Strategic Petroleum Reserve. Since the Strategic Petroleum Reserve crude oil storage facilities program for the 750 minion barrels was completed in 1991, this August 15, 1992, Strategic Petroleum Reserve Quarterly Report focuses on activities related primarily to the storage facilities status, oil acquisition, budget, and cost of the Reserve during the period April 1, 1992, through June 30, 1992.

  17. 17 CFR 229.1203 - (Item 1203) Proved undeveloped reserves.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... reserves that occurred during the year, including proved undeveloped reserves converted into proved developed reserves. (c) Discuss investments and progress made during the year to convert proved...

  18. Combination of CD4+CD25+CD127- regulatory T cells with MLC-BE and BE-Ab2: an efficient evaluation of the therapy of paternal lymphocyte induced immunization in unexplained recurrent spontaneous abortion patients

    PubMed Central

    Yuan, Min-Min; Du, Mei-Rong; Wang, Ming-Yan; Duan, Zhong-Liang; Meng, Yi; Jin, Li-Ping; Li, Ming-Qing; Li, Da-Jin

    2015-01-01

    The aim of this retrospective study was to compare the immune tolerance status of patients suffered from unexplained spontaneous abortion (URSA) before and after treatment with paternal lymphocyte induced immunization (PLII) four times, and its relationship to the pregnancy outcome. 168 URSA patients were included in the present study. Among 168 couples, 138 couples were conceived again, of whom 86 were successfully pregnant till 20 gestational weeks, 31 cases again failed in the first trimester, 21 cases were still under follow-up, another 30 cases still had not conceived. Both the level of one way mixed lymphocyte culture blocking efficiency (MLC-BE) and anti-idio blocking antibody (BE-Ab2) were markedly elevated in succeeded group after PLII. In contrast, although a significant increase could be observed in the failed group after treatment, the elevation of BE-Ab2 was much lower than that in successful group. PLII therapy significantly up-regulated the percentage of peripheral CD4+CD25+CD127- regulatory T cells (Tregs) in successfully pregnant women; however, there was no significant change of Tregs in pregnancy loss cases although receiving PLII therapy. These results suggested a positive correlation between higher frequency of Tregs and rate of successful pregnancies. The sensitivity and specificity of combination of Tregs with MLC-BE and BE-Ab2 were 81.8% and 81.3%, respectively. Therefore, the percentage of Tregs in peripheral blood may hopefully serve as a potential biomarker for monitoring the efficacy of therapy in URSA patients. Combination of Tregs with MLC-BE and BE-Ab2 may expect to better evaluate the efficacy of PLII in URSA patients. PMID:26097590

  19. Marine reserves: size and age do matter.

    PubMed

    Claudet, Joachim; Osenberg, Craig W; Benedetti-Cecchi, Lisandro; Domenici, Paolo; García-Charton, José-Antonio; Pérez-Ruzafa, Angel; Badalamenti, Fabio; Bayle-Sempere, Just; Brito, Alberto; Bulleri, Fabio; Culioli, Jean-Michel; Dimech, Mark; Falcón, Jesús M; Guala, Ivan; Milazzo, Marco; Sánchez-Meca, Julio; Somerfield, Paul J; Stobart, Ben; Vandeperre, Frédéric; Valle, Carlos; Planes, Serge

    2008-05-01

    Marine reserves are widely used throughout the world to prevent overfishing and conserve biodiversity, but uncertainties remain about their optimal design. The effects of marine reserves are heterogeneous. Despite theoretical findings, empirical studies have previously found no effect of size on the effectiveness of marine reserves in protecting commercial fish stocks. Using 58 datasets from 19 European marine reserves, we show that reserve size and age do matter: Increasing the size of the no-take zone increases the density of commercial fishes within the reserve compared with outside; whereas the size of the buffer zone has the opposite effect. Moreover, positive effects of marine reserve on commercial fish species and species richness are linked to the time elapsed since the establishment of the protection scheme. The reserve size-dependency of the response to protection has strong implications for the spatial management of coastal areas because marine reserves are used for spatial zoning.

  20. 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

    ...An open meeting of the Taxpayer Advocacy Panel Small Business/ Self Employed Correspondence Exam Toll Free Project Committee will be conducted. The Taxpayer Advocacy Panel is soliciting public comments, ideas, and suggestions on improving customer service at the Internal Revenue...