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Sample records for surgical learning curve

  1. Novel Uses of Video to Accelerate the Surgical Learning Curve.

    Science.gov (United States)

    Ibrahim, Andrew M; Varban, Oliver A; Dimick, Justin B

    2016-04-01

    Surgeons are under enormous pressure to continually improve and learn new surgical skills. Novel uses of surgical video in the preoperative, intraoperative, and postoperative setting are emerging to accelerate the learning curve of surgical skill and minimize harm to patients. In the preoperative setting, social media outlets provide a valuable platform for surgeons to collaborate and plan for difficult operative cases. Live streaming of video has allowed for intraoperative telementoring. Finally, postoperative use of video has provided structure for peer coaching to evaluate and improve surgical skill. Applying these approaches into practice is becoming easier as most of our surgical platforms (e.g., laparoscopic, and endoscopy) now have video recording technology built in and video editing software has become more user friendly. Future applications of video technology are being developed, including possible integration into accreditation and board certification.

  2. Radius surgical system and conventional laparoscopic instruments in abdominal surgery: application, learning curve and ergonomy.

    Science.gov (United States)

    Di Lorenzo, N; Camperchioli, I; Gaspari, A L

    2007-12-01

    We illustrate our experience with a new class of instruments, the mechanical manipulators (MM), whose main features are an improved mobility, and ergonomy and a modular structure. A specific MM, the Radius Surgical System (RADIUS), has been used both for educational purposes as well as in clinical studies, demonstrating that it can represent an efficient tool to support surgeons performing surgical complex procedures, with a short learning curve for the postural attitude.

  3. Learning curve of a complex surgical technique: minimally invasive transforaminal lumbar interbody fusion (MIS TLIF).

    Science.gov (United States)

    Lee, Kong Hwee; Yeo, William; Soeharno, Henry; Yue, Wai Mun

    2014-10-01

    Prospective cohort study. This study aimed to evaluate the learning curve of minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). Very few studies have evaluated the learning curve of this technically demanding surgery. We intend to evaluate the learning curve of MIS TLIF with a larger sample size and assess surgical competence based not only on operative time but with perioperative variables, clinical and radiologic outcomes, incidence of complications, and patient satisfaction. From 2005 to 2009, the first 90 single-level MIS TLIF, which utilized a consistent technique and spinal instrumentation, performed by a single surgeon at our tertiary institution were studied. Variables studied included operative time, perioperative variables, clinical (Visual Analogue Scores for back and leg pain, Oswestry Disability Index, North American Spine Society Scores for neurogenic symptoms) and radiologic outcomes, incidence of complications and patient rating of expectation met, and the overall result of surgery. The asymptote of the surgeon's learning curve for MIS TLIF was achieved at the 44th case. Comparing the early group of 44 patients to the latter 46, the demographics were similar. For operative parameters, only 3 variables showed differences between the 2 groups: mean operative duration, fluoroscopy duration, and usage of patient-controlled analgesia. At the final follow-up, for clinical outcome parameters, the 2 groups were different in 3 parameters: VAS scores for back, leg pain, and neurogenic symptom scores. For radiologic outcome, both groups showed similar good fusion rates. For complications, none of the MIS TLIF cases were converted to open TLIF intraoperatively. In the early group, there were 3 complications: 1 incidental durotomy and 2 asymptomatic cage migrations; and in the latter group, there was 1 asymptomatic cage migration. In our study, technical proficiency in MIS TLIF was achieved after 44 surgeries, and the latter patients benefited

  4. An evidence-based laparoscopic simulation curriculum shortens the clinical learning curve and reduces surgical adverse events

    Directory of Open Access Journals (Sweden)

    De Win G

    2016-06-01

    Full Text Available Gunter De Win,1,2 Siska Van Bruwaene,3,4 Jyotsna Kulkarni,5 Ben Van Calster,6 Rajesh Aggarwal,7,8 Christopher Allen,9 Ann Lissens,4 Dirk De Ridder,3 Marc Miserez4,10 1Department of Urology, Antwerp University Hospital, 2Faculty of Health Sciences, University of Antwerp, Antwerp, 3Department of Urology, University Hospitals of KU Leuven, 4Centre for Surgical Technologies, KU Leuven, Leuven, Belgium; 5Kulkarni Endo Surgery Institute, Pune, India; 6Department of Development and Regeneration, KU Leuven, Leuven, Belgium; 7Department of Surgery, Faculty of Medicine, 8Steinberg Centre for Simulation and Interactive Learning, Faculty of Medicine, McGill University, Montreal, QC, Canada; 9School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA; 10Department of Abdominal Surgery, University Hospitals Leuven, Leuven, Belgium Background: Surgical simulation is becoming increasingly important in surgical education. However, the method of simulation to be incorporated into a surgical curriculum is unclear. We compared the effectiveness of a proficiency-based preclinical simulation training in laparoscopy with conventional surgical training and conventional surgical training interspersed with standard simulation sessions.Materials and methods: In this prospective single-blinded trial, 30 final-year medical students were randomized into three groups, which differed in the way they were exposed to laparoscopic simulation training. The control group received only clinical training during residency, whereas the interval group received clinical training in combination with simulation training. The Center for Surgical Technologies Preclinical Training Program (CST PTP group received a proficiency-based preclinical simulation course during the final year of medical school but was not exposed to any extra simulation training during surgical residency. After 6 months of surgical residency, the influence on the learning curve while performing

  5. Pedagogic approach in the surgical learning: The first period of “assistant surgeon” may improve the learning curve for laparoscopic robotic-assisted hysterectomy.

    Directory of Open Access Journals (Sweden)

    Angeline Favre

    2016-11-01

    Full Text Available Background: Hysterectomy is the most frequently surgery done with robotic assistance in the world and has been widely studied since its emergence. The surgical outcomes of the robotic hysterectomy are similar to those obtained with other minimally invasive hysterectomy techniques (laparoscopic and vaginal and appear as a promising surgical technique in gynaecology surgery. The aim of this study was to observe the learning curve of robot-assisted hysterectomy in a French surgical center, and was to evaluate the impact of the surgical mentoring.Methods: We retrospectively collected the data from the files of the robot-assisted hysterectomies with the Da Vinci® Surgical System performed between March 2010 and June 2014 at the Foch hospital in Suresnes (France. We first studied the operative time according to the number of cases, independently of the surgeon to determine two periods: the initial learning phase (Phase 1 and the control of surgical skills phase (Phase 2. The phase was defined by mastering the basic surgical tasks. Secondarily we compared these two periods for operative time, blood losses, Body Mass Index (BMI, days of hospitalisations and uterine weight. We finally studied the difference of the learning curve between an experimented surgeon (S1 who practised the first the robot-assisted hysterectomies and a less experimented surgeon (S2 who first assisted S1 and then operated on his own patients.Results: 154 robot-assisted hysterectomies were analysed. 20 procedures were necessary to access to the control of surgical skills phase. There was a significant decrease of the operative time between the learning phase (156.8 minutes compared to the control of surgical skills phase (125.8 minutes, p=0.003. No difference between these two periods for blood losses, BMI, days of hospitalisations and uterine weight were demonstrated. The learning curve of S1 showed 20 procedures to master the robot-assisted hysterectomies with a significant

  6. Can a teaching assistant experience in a surgical anatomy course influence the learning curve for nontechnical skill development for surgical residents?

    Science.gov (United States)

    Heidenreich, Mark J; Musonza, Tashinga; Pawlina, Wojciech; Lachman, Nirusha

    2016-01-01

    The foundation upon which surgical residents are trained to work comprises more than just critical cognitive, clinical, and technical skill. In an environment where the synchronous application of expertise is vital to patient outcomes, the expectation for optimal functioning within a multidisciplinary team is extremely high. Studies have shown that for most residents, one of the most difficult milestones in the path to achieving professional expertise in a surgical career is overcoming the learning curve. This view point commentary provides a reflection from the two senior medical students who have participated in the Student-as-Teacher program developed by the Department of Anatomy at Mayo Clinic, designed to prepare students for their teaching assistant (TA) role in anatomy courses. Both students participated as TAs in a six week surgical anatomy course for surgical first assistant students offered by the School of Health Sciences at Mayo Clinic. Development of teaching skills, nontechnical leadership, communication, and assessment skills, are discussed in relation to their benefits in preparing senior medical students for surgical residency.

  7. Transperitoneal versus extraperitoneal laparoscopic radical prostatectomy during the learning curve: does the surgical approach affect the complication rate?

    Directory of Open Access Journals (Sweden)

    Tiberio M. Siqueira Jr.

    2010-08-01

    Full Text Available Purpose: To compare the perioperative complication rate obtained with the transperitoneal laparoscopic radical prostatectomy (TLRP and with the extraperitoneal LRP (ELRP during the learning curve (LC. Materials and Methods: Data of the initial 40 TLRP (Group 1 were retrospectively compared with the initial 40 ELRP (Group 2. Each Group of patients was operated by two different surgeons. Results: The overall surgical time (175 min x 267.6 min; p < 0.001 and estimated blood loss (177.5 mL x 292.4 mL; p < 0.001 were statistically better in the Group 1. Two intraoperative complications were observed in Group 1 (5% represented by one case of bleeding and one case of rectal injury, whereas four complications (10% were observed in Group 2, represented by two cases of bleeding, one bladder and one rectal injuries (p = 0.675. Open conversion occurred once in each Group (2.5%. Overall postoperative complications were similar (52.5% x 35%; p = 0.365. Major early postoperative complications occurred in three and in one case in Group 1 and 2, respectively. Group 1 had two peritonitis (fecal and urinary, leading to one death in this group. Conclusions: No statistical differences in overall complication rates were observed. The transperitoneal approach presented more serious complications during the early postoperative time and this fact is attributed to the potential chance of intraperitoneal peritonitis not observed with the extraperitoneal route.

  8. Learning Curve? Which One?

    Directory of Open Access Journals (Sweden)

    Paulo Prochno

    2004-07-01

    Full Text Available Learning curves have been studied for a long time. These studies provided strong support to the hypothesis that, as organizations produce more of a product, unit costs of production decrease at a decreasing rate (see Argote, 1999 for a comprehensive review of learning curve studies. But the organizational mechanisms that lead to these results are still underexplored. We know some drivers of learning curves (ADLER; CLARK, 1991; LAPRE et al., 2000, but we still lack a more detailed view of the organizational processes behind those curves. Through an ethnographic study, I bring a comprehensive account of the first year of operations of a new automotive plant, describing what was taking place on in the assembly area during the most relevant shifts of the learning curve. The emphasis is then on how learning occurs in that setting. My analysis suggests that the overall learning curve is in fact the result of an integration process that puts together several individual ongoing learning curves in different areas throughout the organization. In the end, I propose a model to understand the evolution of these learning processes and their supporting organizational mechanisms.

  9. The sales learning curve.

    Science.gov (United States)

    Leslie, Mark; Holloway, Charles A

    2006-01-01

    When a company launches a new product into a new market, the temptation is to immediately ramp up sales force capacity to gain customers as quickly as possible. But hiring a full sales force too early just causes the firm to burn through cash and fail to meet revenue expectations. Before it can sell an innovative product efficiently, the entire organization needs to learn how customers will acquire and use it, a process the authors call the sales learning curve. The concept of a learning curve is well understood in manufacturing. Employees transfer knowledge and experience back and forth between the production line and purchasing, manufacturing, engineering, planning, and operations. The sales learning curve unfolds similarly through the give-and-take between the company--marketing, sales, product support, and product development--and its customers. As customers adopt the product, the firm modifies both the offering and the processes associated with making and selling it. Progress along the manufacturing curve is measured by tracking cost per unit: The more a firm learns about the manufacturing process, the more efficient it becomes, and the lower the unit cost goes. Progress along the sales learning curve is measured in an analogous way: The more a company learns about the sales process, the more efficient it becomes at selling, and the higher the sales yield. As the sales yield increases, the sales learning process unfolds in three distinct phases--initiation, transition, and execution. Each phase requires a different size--and kind--of sales force and represents a different stage in a company's production, marketing, and sales strategies. Adjusting those strategies as the firm progresses along the sales learning curve allows managers to plan resource allocation more accurately, set appropriate expectations, avoid disastrous cash shortfalls, and reduce both the time and money required to turn a profit.

  10. Robotic versus Endoscopic Thyroidectomy for Thyroid Cancers: A Multi-Institutional Analysis of Early Postoperative Outcomes and Surgical Learning Curves

    Directory of Open Access Journals (Sweden)

    Jandee Lee

    2012-01-01

    Full Text Available Robotic thyroidectomy is an emerging technique with postoperative outcomes that are at least comparable to those of conventional endoscopic thyroidectomy, with some end-points appearing superior. Our multicenter series represents the largest comparison of robotic and endoscopic thyroidectomy to date, with results suggesting a comparable robot technology we used that could overcome some of the technical limitations associated with conventional endoscopic procedures, with reduced operation times and increased lymph node retrieval. Moreover, we found that the learning curve for robotic thyroidectomy was shorter than that for endoscopic thyroidectomy.

  11. Straightening Out Learning Curves

    Science.gov (United States)

    Corlett, E. N.; Morecombe, V. J.

    1970-01-01

    The basic mathematical theory behind learning curves is explained, together with implications for clerical and industrial training, evaluation of skill development, and prediction of future performance. Brief studies of textile worker and typist training are presented to illustrate such concepts as the reduction fraction (a consistent decrease in…

  12. Determining the Learning Curve of Transcutaneous Laryngeal Ultrasound in Vocal Cord Assessment by CUSUM Analysis of Eight Surgical Residents: When to Abandon Laryngoscopy.

    Science.gov (United States)

    Wong, Kai-Pun; Lang, Brian Hung-Hin; Lam, Shi; Au, Kin-Pan; Chan, Diane Toi-yin; Kotewall, Nicholas Clarence

    2016-03-01

    Transcutaneous laryngeal ultrasonography (TLUSG) is a promising alternative to laryngoscopy in vocal cords (VCs) assessment which might be challenging in the beginning. However, it remains unclear when an assessor can provide proficient TLUSG enough to abandon direct laryngoscopy . Eight surgical residents (SRs) without prior USG experience were recruited to determine the learning curve. After a standardized training program, SRs would perform 80 consecutive peri-operative VCs assessment using TLUSG. Performances of SRs were quantitatively evaluated by a composite performance score (lower score representing better performance) which comprised total examination time (in seconds), VCs visualization, and assessment accuracy. Cumulative sum (CUSUM) chart was then used to evaluate learning curve. Diagnostic accuracy and demographic data between every twentieth TLUSG were compared. 640 TLUSG examinations had been performed by 8 residents. 95.1% of VCs could be assessed by SRs. The CUSUM curve showed a rising pattern (learning phase) until 7th TLUSG and then flattened. The curve declined continuously after 42nd TLUSG (after reaching a plateau). Rates of assessable VCs were comparable in every twentieth cases performed. It took a longer time to complete TLUSG in 1st-20th than 21st-40th examinations. (45 vs. 32s, p = 0.001). Although statistically not significant, proportion of false-negative results was higher in 21st-40th (2.5%) than 1(st)-20th (0.6%), 41(st)-60th (0.7%), and 61(st)-80th (0.7%) TLUSG performed. After a short formal training, surgeons could master skill in TLUSG after seven examination and assess vocal cord function consistently and accurately after 40 TLUSG.

  13. The surgical learning curve for robotic-assisted laparoscopic radical prostatectomy:experience of a single surgeon with 500cases in Taiwan, China

    Institute of Scientific and Technical Information of China (English)

    YenChuan Ou; ChunKuang Yang; KuanghSi Chang; John Wang; SiuWan Hung; MinChe Tung; Ashutosh K Tewari; Vipul R Patel

    2014-01-01

    To analyze the learning curve for cancer control from an initial 250cases(GroupI) and subsequent 250cases(GroupII) of robotic‑assisted laparoscopic radical prostatectomy(RALP) performed by a single surgeon. Five hundred consecutive patients with clinically localized prostate cancer received RALP and were evaluated. Surgical parameters and perioperative complications were compared between the groups. Positive surgical margin(PSM) and biochemical recurrence(BCR) were assessed as cancer control outcomes. Patients in GroupII had signiifcantly more advanced prostate cancer than those in GroupI(22.2%vs 14.2%, respectively, with Gleason score 8–10,P=0.033; 12.8%vs 5.6%, respectively, with clinical stage T3,P=0.017). The incidence of PSM in pT3 was decreased signiifcantly from 49% in GroupI to 32.6% in GroupII. Ameaningful trend was noted for a decreasing PSM rate with each consecutive group of 50cases, including pT3 and high‑risk patients. Neurovascular bundle(NVB) preservation was signiifcantly inlfuenced by the PSM in high‑risk patients(84.1% in the preservation groupvs 43.9% in the nonpreservation group). The 3‑year, 5‑year, and 7‑year BCR‑free survival rates were 79.2%, 75.3%, and 70.2%, respectively. In conclusion, the incidence of PSM in pT3 was decreased signiifcantly after 250cases. There was a trend in the surgical learning curve for decreasing PSM with each group of 50cases. NVB preservation during RALP for the high‑risk group is not suggested due to increasing PSM.

  14. Perioperative Surgical Complications and Learning Curve Associated with Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Single-Institute Experience

    OpenAIRE

    Park, Yung; Lee, Soo Bin; Seok, Sang Ok; Jo, Byung Woo; Ha, Joong Won

    2015-01-01

    Background As surgical complications tend to occur more frequently in the beginning stages of a surgeon's career, knowledge of perioperative complications is important to perform a safe procedure, especially if the surgeon is a novice. We sought to identify and describe perioperative complications and their management in connection with minimally invasive transforaminal lumbar interbody fusion (TLIF). Methods We performed a retrospective chart review of our first 124 patients who underwent mi...

  15. Can a Teaching Assistant Experience in a Surgical Anatomy Course Influence the Learning Curve for Nontechnical Skill Development for Surgical Residents?

    Science.gov (United States)

    Heidenreich, Mark J.; Musonza, Tashinga; Pawlina, Wojciech; Lachman, Nirusha

    2016-01-01

    The foundation upon which surgical residents are trained to work comprises more than just critical cognitive, clinical, and technical skill. In an environment where the synchronous application of expertise is vital to patient outcomes, the expectation for optimal functioning within a multidisciplinary team is extremely high. Studies have shown…

  16. Analysis of the vitreoretinal surgery learning curve.

    Science.gov (United States)

    Martín-Avià, J; Romero-Aroca, P

    2017-06-01

    To describe intra- and post-operative complications, as well as the evolution of the surgical technique in first 4years of work of a novice retina surgeon, and evaluate minimal learning time required to reduce its complications, deciding which pathologies should still be referred to higher level hospitals, until further experience may be achieved. A study was conducted on patients that had undergone vitreoretinal surgery by a novice surgeon in Tarragona between 23rd October 2007 and 31st December 2011. The primary diagnosis, surgeon learning time, surgical technique, intra-operative and post-operative complications were recorded. A total of 247 surgeries were studied. The percentage of use of 20G and 23G calibres during the time, marks a change towards trans-conjunctival surgery from the ninth trimester (98 surgeries). Surgical complications decreased towards twelfth trimester (130 surgeries) with an increase in the previous months. The shift towards 23G technique around 100 surgeries is interpreted as greater comfort and safety by the surgeon. Increased surgical complications during the following months until its decline around 130 surgeries can be interpreted as an 'overconfidence'. It is arguable that the learning curve is slower than what the surgeon believes. An individual analysis of the complications and surgical outcomes is recommended to ascertain the status of the learning curve. Copyright © 2016 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

  17. Analysis of the learning curve for transurethral resection of the prostate. Is there any influence of musical instrument and video game skills on surgical performance?

    Science.gov (United States)

    Yamaçake, Kleiton Gabriel Ribeiro; Nakano, Elcio Tadashi; Soares, Iva Barbosa; Cordeiro, Paulo; Srougi, Miguel; Antunes, Alberto Azoubel

    2015-09-01

    To evaluate the learning curve for transurethral resection of the prostate (TURP) among urology residents and study the impact of video game and musical instrument playing abilities on its performance. A prospective study was performed from July 2009 to January 2013 with patients submitted to TURP for benign prostatic hyperplasia. Fourteen residents operated on 324 patients. The following parameters were analyzed: age, prostate-specific antigen levels, prostate weight on ultrasound, pre- and postoperative serum sodium and hemoglobin levels, weight of resected tissue, operation time, speed of resection, and incidence of capsular lesions. Gender, handedness, and prior musical instrument and video game playing experience were recorded using survey responses. The mean resection speed in the first 10 procedures was 0.36 g/min and reached a mean of 0.51 g/min after the 20(th) procedure. The incidence of capsular lesions decreased progressively. The operation time decreased progressively for each subgroup regardless of the difference in the weight of tissue resected. Those experienced in playing video games presented superior resection speed (0.45 g/min) when compared with the novice (0.35 g/min) and intermediate (0.38 g/min) groups (p=0.112). Musical instrument playing abilities did not affect the surgical performance. Speed of resection, weight of resected tissue, and percentage of resected tissue improve significantly and the incidence of capsular lesions reduces after the performance of 10 TURP procedures. Experience in playing video games or musical instruments does not have a significant effect on outcomes.

  18. S-shaped learning curves

    NARCIS (Netherlands)

    Murre, J.M.J.

    2014-01-01

    In this article, learning curves for foreign vocabulary words are investigated, distinguishing between a subject-specific learning rate and a material-specific parameter that is related to the complexity of the items, such as the number of syllables. Two experiments are described, one with Turkish w

  19. Learning curve for radical retropubic prostatectomy

    Directory of Open Access Journals (Sweden)

    Fernando J. A. Saito

    2011-02-01

    Full Text Available PURPOSE: The learning curve is a period in which the surgical procedure is performed with difficulty and slowness, leading to a higher risk of complications and reduced effectiveness due the surgeon's inexperience. We sought to analyze the residents' learning curve for open radical prostatectomy (RP in a training program. MATERIALS AND METHODS: We conducted a prospective study from June 2006 to January 2008 in the academic environment of the University of São Paulo. Five residents operated on 184 patients during a four-month rotation in the urologic oncology division, mentored by the same physician assistants. We performed sequential analyses according to the number of surgeries, as follows: = 10, 11 to 19, 20 to 28, and = 29. RESULTS: The residents performed an average of 37 RP each. The average psa was 9.3 ng/mL and clinical stage T1c in 71% of the patients. The pathological stage was pT2 (73%, pT3 (23%, pT4 (4%, and 46% of the patients had a Gleason score 7 or higher. In all surgeries, the average operative time and estimated blood loss was 140 minutes and 488 mL. Overall, 7.2% of patients required blood transfusion, and 23% had positive surgical margins. CONCLUSION: During the initial RP learning curve, we found a significant reduction in the operative time; blood transfusion during the procedures and positive surgical margin rate were stable in our series.

  20. Learning curve in cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

    Science.gov (United States)

    Moradi, Bijan N; Esquivel, Jesus

    2009-09-15

    Cytoreductive surgery and Hyperthermic Intraperitoneal Chemotherapy have achieved good long-term results in patients with complete surgical eradication of their peritoneal dissemination but at the expense of significant perioperative morbidity and mortality. The high complication rate has been attributed to the steep learning curve associated with this procedure. We report on the current literature regarding the learning curve for this procedure and the key components that determine the success in learning this new skill.

  1. Optimal investment in learning-curve technologies

    NARCIS (Netherlands)

    Della Seta, M.; Gryglewicz, S.; Kort, P.M.

    2012-01-01

    We study optimal investment in technologies characterized by the learning curve. There are two investment patterns depending on the shape of the learning curve. If the learning process is slow, firms invest relatively late and on a larger scale. If the curve is steep, firms invest earlier and on a s

  2. The learning curve in revision cholesteatoma surgery.

    Science.gov (United States)

    Stankovic, Milan

    2013-01-01

    To review the results of revision surgery for cholesteatoma. Retrospective review of patient's records. Tertiary referral center. A retrospective study of patients operated for acquired middle ear cholesteatoma during the period 1990-2002 was performed. A total of 758 patients were divided into two groups according to surgical experience, and followed during short-term and long-term period. The cholesteatoma was divided according to location, age of patients, status of auditory ossicles, and bilaterality of disease. The patients were treated with single canal wall up or wall down, according to the propagation of disease and condition of middle ear. The indications for the reoperations were: recurrent or residual cholesteatoma, resuppuration, and AB gap more than 20 dB. Type of surgical therapy, localization of cholesteatoma, age of patients, revisions, bilaterality of disease, damage of auditory ossicles and learning curve were analyzed. The number of revision operations was reduced in the second period (from totally 24.3% to 16.4%). Closed technique gave a significantly lower rate of failure. For attic cholesteatoma, adults, bilateral disease, and ossicular damage the rate of revisions was significantly lower with surgical experience. Surgical experience was important for reduction of reoperation rate for attic and sinus cholesteatoma, adults, bilateral cholesteatoma, and when closed technique is used. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Superior quality of life and improved surgical margins are achievable with robotic radical prostatectomy after a long learning curve: a prospective single-surgeon study of 1552 consecutive cases.

    Science.gov (United States)

    Thompson, James E; Egger, Sam; Böhm, Maret; Haynes, Anne-Maree; Matthews, Jayne; Rasiah, Krishan; Stricker, Phillip D

    2014-03-01

    Comparative studies suggest functional and perioperative superiority of robot-assisted radical prostatectomy (RARP) over open radical prostatectomy (ORP). To determine whether high-volume experienced open surgeons can improve their functional and oncologic outcomes with RARP and, if so, how many cases are required to surpass ORP outcomes and reach the learning curve plateau. A prospective observational study compared two surgical techniques: 1552 consecutive men underwent RARP (866) or ORP (686) at a single Australian hospital from 2006 to 2012, by one surgeon with 3000 prior ORPs. Demographic and clinicopathologic data were collected prospectively. The Expanded Prostate Cancer Index Composite quality of life (QoL) questionnaire was administered at baseline, 1.5, 3, 6, 12, and 24 mo. Multivariate linear and logistic regression modelled the difference in QoL domains and positive surgical margin (PSM) odds ratio (OR), respectively, against case number. A total of 1511 men were included in the PSM and 609 in the QoL analysis. RARP sexual function scores surpassed ORP scores after 99 RARPs and increased to a mean difference at 861st case of 11.0 points (95% confidence interval [CI], 5.9-16.1), plateauing around 600-700 RARPs. Early urinary incontinence scores for RARP surpassed ORP after 182 RARPs and increased to a mean difference of 8.4 points (95% CI, 2.1-14.7), plateauing around 700-800 RARPs. The odds of a pT2 PSM were initially higher for RARP but became lower after 108 RARPs and were 55% lower (OR: 0.45; 95% CI, 0.22-0.92) by the 866th RARP. The odds of a pT3/4 PSM were initially higher for RARP but decreased, plateauing around 200-300 RARPs with an OR of 1.15 (0.68-1.95) at the 866th RARP. Limitations include single-surgeon data and residual confounding. RARP had a long learning curve with inferior outcomes initially, and then showed progressively superior sexual, early urinary, and pT2 PSM outcomes and similar pT3 PSM and late urinary outcomes. Learning RARP

  4. Learning curves in energy planning models

    Energy Technology Data Exchange (ETDEWEB)

    Barreto, L.; Kypreos, S. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    This study describes the endogenous representation of investment cost learning curves into the MARKAL energy planning model. A piece-wise representation of the learning curves is implemented using Mixed Integer Programming. The approach is briefly described and some results are presented. (author) 3 figs., 5 refs.

  5. Investigation of learning and experience curves

    Energy Technology Data Exchange (ETDEWEB)

    Krawiec, F.; Thornton, J.; Edesess, M.

    1980-04-01

    The applicability of learning and experience curves for predicting future costs of solar technologies is assessed, and the major test case is the production economics of heliostats. Alternative methods for estimating cost reductions in systems manufacture are discussed, and procedures for using learning and experience curves to predict costs are outlined. Because adequate production data often do not exist, production histories of analogous products/processes are analyzed and learning and aggregated cost curves for these surrogates estimated. If the surrogate learning curves apply, they can be used to estimate solar technology costs. The steps involved in generating these cost estimates are given. Second-generation glass-steel and inflated-bubble heliostat design concepts, developed by MDAC and GE, respectively, are described; a costing scenario for 25,000 units/yr is detailed; surrogates for cost analysis are chosen; learning and aggregate cost curves are estimated; and aggregate cost curves for the GE and MDAC designs are estimated. However, an approach that combines a neoclassical production function with a learning-by-doing hypothesis is needed to yield a cost relation compatible with the historical learning curve and the traditional cost function of economic theory.

  6. Piecewise power laws in individual learning curves.

    Science.gov (United States)

    Donner, Yoni; Hardy, Joseph L

    2015-10-01

    The notion that human learning follows a smooth power law (PL) of diminishing gains is well-established in psychology. This characteristic is observed when multiple curves are averaged, potentially masking more complex dynamics underpinning the curves of individual learners. Here, we analyzed 25,280 individual learning curves, each comprising 500 measurements of cognitive performance taken from four cognitive tasks. A piecewise PL (PPL) model explained the individual learning curves significantly better than a single PL, controlling for model complexity. The PPL model allows for multiple PLs connected at different points in the learning process. We also explored the transition dynamics between PL curve component pieces. Performance in later pieces typically surpassed that in earlier pieces, after a brief drop in performance at the transition point. The transition rate was negatively associated with age, even after controlling for overall performance. Our results suggest at least two processes at work in individual learning curves: locally, a gradual, smooth improvement, with diminishing gains within a specific strategy, which is modeled well as a PL; and globally, a discrete sequence of strategy shifts, in which each strategy is better in the long term than the ones preceding it. The piecewise extension of the classic PL of practice has implications for both individual skill acquisition and theories of learning.

  7. Learning Curves of Virtual Mastoidectomy in Distributed and Massed Practice

    DEFF Research Database (Denmark)

    Andersen, Steven Arild Wuyts; Konge, Lars; Cayé-Thomasen, Per

    2015-01-01

    IMPORTANCE: Repeated and deliberate practice is crucial in surgical skills training, and virtual reality (VR) simulation can provide self-directed training of basic surgical skills to meet the individual needs of the trainee. Assessment of the learning curves of surgical procedures is pivotal......, AND PARTICIPANTS: A prospective trial with a 2 × 2 design was conducted at an academic teaching hospital. Participants included 43 novice medical students. Of these, 21 students completed time-distributed practice from October 14 to November 29, 2013, and a separate group of 19 students completed massed practice...... on May 16, 17, or 18, 2014. Data analysis was performed from June 6, 2014, to March 3, 2015. INTERVENTIONS: Participants performed 12 repeated virtual mastoidectomies using a temporal bone surgical simulator in either a distributed (practice blocks spaced in time) or massed (all practice in 1 day...

  8. The learning curves of competitive programming

    Science.gov (United States)

    Garcia, Jose R.; Aguirre, Vanessa E.

    2014-10-01

    Universities around the world have implemented competitive programming as an approach to teach computer science courses. They have empirically validated this approach as a successful pedagogical tool. However, there are no conclusive results that describe the degree in which competitive programming affects the learning process of the students. In this paper, we report on the learning curves obtained from analyzing ten years of TopCoder algorithm competitions. We discuss on how these learning curves apply to university courses and can help us explain the influence of competitive programming in a class.

  9. Management of the learning curve

    DEFF Research Database (Denmark)

    Pedersen, Peter-Christian; Slepniov, Dmitrij

    2016-01-01

    with measures that have the potential to significantly reduce the non-value-added time when establishing new capacities overseas. Originality/value – The paper uses a longitudinal in-depth case study of a Danish wind turbine manufacturer and goes beyond a simplistic treatment of the lead time and learning...

  10. A learning curve for solar thermal power

    Science.gov (United States)

    Platzer, Werner J.; Dinter, Frank

    2016-05-01

    Photovoltaics started its success story by predicting the cost degression depending on cumulated installed capacity. This so-called learning curve was published and used for predictions for PV modules first, then predictions of system cost decrease also were developed. This approach is less sensitive to political decisions and changing market situations than predictions on the time axis. Cost degression due to innovation, use of scaling effects, improved project management, standardised procedures including the search for better sites and optimization of project size are learning effects which can only be utilised when projects are developed. Therefore a presentation of CAPEX versus cumulated installed capacity is proposed in order to show the possible future advancement of the technology to politics and market. However from a wide range of publications on cost for CSP it is difficult to derive a learning curve. A logical cost structure for direct and indirect capital expenditure is needed as the basis for further analysis. Using derived reference cost for typical power plant configurations predictions of future cost have been derived. Only on the basis of that cost structure and the learning curve levelised cost of electricity for solar thermal power plants should be calculated for individual projects with different capacity factors in various locations.

  11. Learning curve of acetabular cup positioning in total hip arthroplasty using a cumulative summation test for learning curve (LC-CUSUM).

    Science.gov (United States)

    Lee, Young-Kyun; Biau, David J; Yoon, Byung-Ho; Kim, Tae-Young; Ha, Yong-Chan; Koo, Kyung-Hoi

    2014-03-01

    Despite advances in surgical techniques and instrumentation, optimal cup positioning in total hip arthroplasty (THA) is challenging with a limited accuracy. We evaluated whether a learning curve exists for the optimal cup positioning, using the LC-CUSUM test (Learning curve cumulative summation test). We evaluated the first 100 consecutive THA performed by two surgeons, who had a year of fellowship training in the same teaching hospital. A learning curve of cup positioning was plotted in each series using the LC-CUSUM score. There was no significant difference of numbers of outlier between two surgeons (P = 0.079). Both surgeons completed the learning curve of optimal cup positioning before 50 procedures, and maintained competence. A substantial learning period is necessary in the optimal positioning of an acetabular cup.

  12. Learning curve of vitrification assessed by cumulative summation test for learning curve (LC-CUSUM).

    Science.gov (United States)

    Dessolle, Lionel; Biau, David J; de Larouzière, Vanina; Ravel, Célia; Antoine, Jean-Marie; Daraï, Emile; Mandelbaum, Jacqueline

    2009-09-01

    We used the cumulative summation test for learning curve (LC-CUSUM), a specifically designed statistical tool, to evaluate the first 50 procedures performed by a trainee in vitrification and to provide a usable model for monitoring the learning process of this technique. Given the lack of models to evaluate IVF technologies, the CUSUM methodology could prove useful for quality control in laboratories.

  13. LEARNING CURVE IN ENDOSCOPIC TRANSNASAL SELLAR REGION SURGERY

    Directory of Open Access Journals (Sweden)

    Ananth G

    2016-07-01

    Full Text Available BACKGROUND The endoscopic endonasal approach for the sellar region lesions is a novel technique and an effective surgical option. The evidence thus far has been conflicting with reports in favour and against a learning curve. We attempt to determine the learning curve associated with this approach. METHODS Retrospective and prospective data of the patients who were surgically treated for sellar region lesions between the year 2013 and 2016 was collected, 32 patients were operated by the endoscopic endonasal approach at Vydehi Institute of Medical Sciences and Research Centre, Bangalore. Age, sex, presenting symptoms, length of hospital stay, surgical approach, type of dissection, duration of surgery, sellar floor repair, intraoperative and postoperative complications were noted. All the procedures were performed by a single neurosurgeon. RESULTS A total of 32 patients were operated amongst which 21 patients were non-functioning pituitary adenomas, 2 were growth hormone secreting functional adenomas, 1 was an invasive pituitary adenoma, 4 were craniopharyngiomas, 2 were meningiomas, 1 was Rathke’s cleft cyst and 1 was a clival chordoma. Headache was the mode of presentation in 12 patients, 12 patients had visual deficits, 6 patients presented with hormonal disturbances amongst which 4 patients presented with features of panhypopituitarism and 2 with acromegaly. Amongst the 4 patients with panhypopituitarism, 2 also had DI, two patients presented with CSF rhinorrhoea. There was a 100% improvement in the patients who presented with visual symptoms. Gross total resection was achieved in all 4 cases of craniopharyngiomas and 13 cases of pituitary adenomas. Postoperative CSF leak was seen in 4 patients who underwent re-exploration and sellar floor repair, 9 patients had postoperative Diabetes Insipidus (DI which was transient, the incidence of DI reduced towards the end of the study. There was a 25% decrease in the operating time towards the end of

  14. [Surgical adrenal approaches: learned experiences].

    Science.gov (United States)

    Bravo-Lázaro, Santos; Hernandis-Villalba, Juan; Meroño-Carbajosa, Emilio; Navío-Perales, Juan; Marzal-Felici, Vicente

    2014-01-01

    Laparoscopic surgery is the standard approach for surgical adrenal gland pathology. However, the open procedure still has its role. Our intention is to report our results and experience using different techniques. A retrospective study of 40 patients was carried out. Demographic and surgical data were analyzed. Thirty two patients had benign pathology and eight had malignant tumors. Laparotomy was performed in 18 patients: seven patients with malignant tumors and 11 with benign pathology. Young's approach was indicated in four patients. Laparoscopic aproach was indicated in 25 patients with seven patients requiring conversion to laparotomy. The conversion rate was 28% In most cases, the laparoscopic approach is the standard technique. Appropriate case selection is of primary importance. Other surgical techniques should be considered if necessary.

  15. The learning curves in living donor hemiliver graft procurement using small upper midline incision.

    Science.gov (United States)

    Ikegami, Toru; Harimoto, Norifumi; Shimokawa, Masahiro; Yoshizumi, Tomoharu; Uchiyama, Hideaki; Itoh, Shinji; Okabe, Norihisa; Sakata, Kazuhito; Nagatsu, Akihisa; Soejima, Yuji; Maehara, Yoshihiko

    2016-12-01

    The learning curve for performing living donor hemiliver procurement (LDHP) via small upper midline incision (UMI) has not been determined. Living donors (n=101) who underwent LDHP via UMI were included to investigate the learning curve using cumulative sum analysis. The cumulative sum analysis showed that nine cases for right lobe (case #23) and 19 cases for left lobe (case #32 in the whole series) are needed for stable and acceptable surgical outcomes in LDHP via UMI. The established phase (n=69, since case #33) had a significantly shorter operative time, a smaller incision size, and less blood loss than the previous learning phase (n=32, serial case number up to the last 19th left lobe case). Multivariate analysis showed that the learning phase, high body mass index ≥25 kg/m(2) , and left lobe graft procurement are the factors associated with surgical events including operative blood loss ≥400 mL, operative time ≥300 minutes, or surgical complications ≥Clavien-Dindo grade II. There is an obvious learning curve in performing LDHP via UMI, and 32 cases including both 19 cases for left lobe and nine cases for right lobe are needed for having stable and acceptable surgical outcomes.

  16. Automated Blazar Light Curves Using Machine Learning

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Spencer James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-07-27

    This presentation describes a problem and methodology pertaining to automated blazar light curves. Namely, optical variability patterns for blazars require the construction of light curves and in order to generate the light curves, data must be filtered before processing to ensure quality.

  17. The Surgical Scrub. Learning Activity Package.

    Science.gov (United States)

    Runge, Lillian

    This learning activity package on the surgical scrub is one of a series of 12 titles developed for use in health occupations education programs. Materials in the package include objectives, a list of materials needed, a list of definitions, information sheets, reviews (self evaluations) of portions of the content, and answers to reviews. These…

  18. A Critical Analysis of the Learning Curve and Postlearning Curve Outcomes of Two Experience- and Volume-Matched Surgeons for Laparoscopic and Robot-Assisted Radical Prostatectomy.

    Science.gov (United States)

    Good, Daniel W; Stewart, Grant D; Laird, Alexander; Stolzenburg, Jens-Uwe; Cahill, Declan; McNeill, S Alan

    2015-08-01

    There remains equipoise with regard to whether laparoscopic radical prostatectomy (LRP) or robot-assisted radical prostatectomy (RARP) has any benefit over the other. Despite this, there is a trend for the increasing adoption of RARP at great cost to health services across the world. The aim was to critically analyze the learning curve and outcomes for LRP and RARP for two experience- and volume-matched surgeons who have completed the learning curve for LRP and RARP. Two experience- and volume-matched LRP and RARP surgeons who have completed the learning curve were compared with respect to their learning curve and outcomes for RARP and LRP. There were 531 RARP and 550 LRPs analyzed from April 2003 until January 2012 at two relatively high-volume United Kingdom centers. Outcome measures included operative time, blood loss, complication rate (Clavien-Dindo grade III), positive surgical margin (PSM) rate, and early continence rate. Learning curves for blood loss, operative times, and complication rate were similar between groups. The overall PSM rate and pT2 PSM rate learning curves were longer for RARP compared with LRP but shorter for early continence. Apical PSM showed no learning curve for RARP; however, a long learning curve for LRP and the rate was lower for RARP than for LRP (P=learning curves. Despite the long learning curve for RARP, significant benefits in lower PSM rates and better early continence in comparison with LRP exist. There are benefits to patients with RARP over LRP, especially those linked to better apical dissection (apical PSM and early continence).

  19. Shaping the learning curve: epigenetic dynamics in neural plasticity

    Directory of Open Access Journals (Sweden)

    Zohar Ziv Bronfman

    2014-07-01

    Full Text Available A key characteristic of learning and neural plasticity is state-dependent acquisition dynamics reflected by the non-linear learning curve that links increase in learning with practice. Here we propose that the manner by which epigenetic states of individual cells change during learning contributes to the shape of the neural and behavioral learning curve. We base our suggestion on recent studies showing that epigenetic mechanisms such as DNA methylation, histone acetylation and RNA-mediated gene regulation are intimately involved in the establishment and maintenance of long-term neural plasticity, reflecting specific learning-histories and influencing future learning. Our model, which is the first to suggest a dynamic molecular account of the shape of the learning curve, leads to several testable predictions regarding the link between epigenetic dynamics at the promoter, gene-network and neural-network levels. This perspective opens up new avenues for therapeutic interventions in neurological pathologies.

  20. Learning Curves in Robotic Rectal Cancer Surgery: A literature Review

    Directory of Open Access Journals (Sweden)

    Nasir

    2016-10-01

    Full Text Available Background Laparoscopic rectal cancer surgery offers several advantages over open surgery, including quicker recovery, shorter hospital stay and improved cosmesis. However, laparoscopic rectal surgery is technically difficult and is associated with a long learning curve. The last decade has seen the emergence of robotic rectal cancer surgery. In contrast to laparoscopy, robotic surgery offers stable 3D views with advanced dexterity and ergonomics in narrow spaces such as the pelvis. Whether this translates into a shorter learning curve is still debated. The aim of this literature search is to ascertain the learning curve of robotic rectal cancer surgery. Methods This review analyses the literature investigating the learning curve of robotic rectal cancer surgery. Using the Medline database a literature search of articles investigating the learning curve of robotic rectal surgery was performed. All relevant articles were included. Results Twelve original studies fulfilled the inclusion criteria. The current literature suggests that the learning curve of robotic rectal surgery varies between 15 and 44 cases and is probably shorter to that of laparoscopic rectal surgery. Conclusions There are only a few studies assessing the learning curve of robotic rectal surgery and they possess several differences in methodology and outcome reporting. Nevertheless, current evidence suggests that robotic rectal surgery might be easier to learn than laparoscopy. Further well designed studies applying CUSSUM analysis are required to validate this motion.

  1. Identifying the learning curve for total ankle replacement using a mobile bearing prosthesis.

    Science.gov (United States)

    Usuelli, Federico G; Maccario, Camilla; Pantalone, Andrea; Serra, Nicola; Tan, Eric W

    2017-06-01

    Total ankle arthroplasty remains a technically demanding surgery highly influenced by the operator experience. However, no consensus exists regarding the ideal number of cases that need to be performed before a surgeon is considered proficient. The aim of this study was to identify the learning curve of a specific replacement system with regards to intraoperative and postoperative outcomes. The first 31 patients undergoing total ankle arthroplasty were examined. No additional procedures were performed at the time of the TAA. Intraoperative characteristics, postoperative complications, as well as clinical and radiologic outcomes were assessed with 24-month follow-up. Learning curves, examining the relationship between surgeon experience and patient outcomes, were determined using the Moving Average Method. The operatory time, and the risk of intraoperative fractures decreased with increasing surgeon experience with the learning curve stabilizing after the 14th and 24th patient, respectively. Furthermore, there appeared to be a learning curve associated with most of the important clinical and radiological outcomes. The number of patients required to stabilize the learning curve for the VAS, ROM, and AOFAS was 11, 14 and 28, respectively. Radiographically, there appeared to be a learning curve of 22 patients required to stabilize the tibio-talar ratio. There was no learning curve associated with the SF-12 PCS and MCS as well as the α-, β-, and γ-angle. This study demonstrates that a surgical learning curve does indeed exist when performing TAA. Most of the operative variables as well as clinical and radiological outcomes stabilize after a surgeon has performed 28 cases. Copyright © 2016 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

  2. Learning style preferences of surgical residency applicants.

    Science.gov (United States)

    Kim, Roger H; Gilbert, Timothy

    2015-09-01

    The learning style preferences of general surgery residents have been previously reported; there is evidence that residents who prefer read/write learning styles perform better on the American Board of Surgery In-Training Examination (ABSITE). However, little is known regarding the learning style preferences of applicants to general surgery residency and their impact on educational outcomes. In this study, the preferred learning styles of surgical residency applicants were determined. We hypothesized that applicant rank data are associated with specific learning style preferences. The Fleming VARK learning styles inventory was offered to all general surgery residency applicants that were interviewed at a university hospital-based program. The VARK model categorizes learners as visual (V), aural (A), read/write (R), kinesthetic (K), or multimodal (MM). Responses on the inventory were scored to determine the preferred learning style for each applicant. Applicant data, including United States Medical Licensing Examination (USMLE) scores, class rank, interview score, and overall final applicant ranking, were examined for association with preferred learning styles. Sixty-seven applicants were interviewed. Five applicants were excluded due to not completing the VARK inventory or having incomplete applicant data. The remaining 62 applicants (92%) were included for analysis. Most applicants (57%) had a multimodal preference. Sixty-nine percent of all applicants had some degree of preference for kinesthetic learning. There were statistically significant differences between applicants of different learning styles in terms of USMLE step 1 scores (P = 0.001) and USMLE step 2 clinical knowledge scores (P = 0.01), but not for class ranks (P = 0.27), interview scores (P = 0.20), or final ranks (P = 0.14). Multiple comparison analysis demonstrated that applicants with aural preferences had higher USMLE 1 scores (233.2) than those with kinesthetic (211.8, P = 0.005) or multimodal

  3. A uniquely shaped rod improves curve correction in surgical treatment of adolescent idiopathic scoliosis

    DEFF Research Database (Denmark)

    Gehrchen, Poul Martin; Ohrt-Nissen, Søren; Hallager, Dennis Winge

    2016-01-01

    Study Design. A retrospective cohort study.  Objective. The aim of this study is to determine the initial curve correction in patients surgically treated for adolescent idiopathic scoliosis (AIS) using either beam-like rods (BRs) or traditional circular rods (CRs).  Summary of Background Data. Po...

  4. Learning curves and collaboration in reconceiving refugee settlements

    Directory of Open Access Journals (Sweden)

    Mariano-Florentino Cuéllar

    2014-09-01

    Full Text Available A collaboration between UNHCR, Ennead Architects and Stanford University uses settlement design to promote innovation and further development in the refugee protection model but collaborators initially face a steep learning curve.

  5. Implementation Learning and Forgetting Curve to Scheduling in Garment Industry

    Science.gov (United States)

    Muhamad Badri, Huda; Deros, Baba Md; Syahri, M.; Saleh, Chairul; Fitria, Aninda

    2016-02-01

    The learning curve shows the relationship between time and the cumulative number of units produced which using the mathematical description on the performance of workers in performing repetitive works. The problems of this study is level differences in the labors performance before and after the break which affects the company's production scheduling. The study was conducted in the garment industry, which the aims is to predict the company production scheduling using the learning curve and forgetting curve. By implementing the learning curve and forgetting curve, this paper contributes in improving the labors performance that is in line with the increase in maximum output 3 hours productive before the break are 15 unit product with learning curve percentage in the company is 93.24%. Meanwhile, the forgetting curve improving maximum output 3 hours productive after the break are 11 unit product with the percentage of forgetting curve in the company is 92.96%. Then, the obtained 26 units product on the productive hours one working day is used as the basic for production scheduling.

  6. Surgical learning activities for house officers: do they improve the surgical experience?

    Science.gov (United States)

    Maweni, R M; Foley, R W; Lupi, M; Shier, D; Ronan O'Connell, P; Vig, S

    2016-11-01

    To ascertain whether house officers (HOs) attain a more satisfactory surgical rotation experience when they perform basic surgical learning activities. We also sought to establish how many and which learning activities HOs achieve and the effect on their surgical experience. A questionnaire listing 20 learning activities and questions regarding satisfaction with an overall experience was disseminated to HOs in the UK and Ireland who had completed ≥3 months of surgical rotations. Satisfaction with surgical experience was dichotomised in order to perform logistic regression using R Studio software v0.98. The survey was completed by 150 respondents, with 26 % completing at least 10 basic surgical learning activities during their surgical rotation. On multivariate analysis, the completion of these learning activities was significantly associated with a satisfactory rotation experience (p learning activities (p = 0.003). Surgical HOs who were informed about potential basic surgical learning activities that can be performed during their rotations performed significantly more of these activities. And these activities were associated with a significantly greater satisfaction with surgical rotations. Therefore, we recommend facilitating HOs completion of these activities as this will ensure that basic surgical competencies are achieved and that HOs will be more satisfied with their surgical experience.

  7. Pathologic outcomes during the learning curve for robotic-assisted laparoscopic radical prostatectomy

    Directory of Open Access Journals (Sweden)

    Amul Shah

    2008-03-01

    Full Text Available OBJECTIVE: We report our initial experience with 62 patients undergoing robotic-assisted laparoscopic prostatectomy (RALP, focusing on the primary parameter of positive surgical margins. The authors demonstrate that excellent oncologic outcomes can be attained with a less steep learning curve than previously hypothesized. MATERIALS AND METHODS: The first 62 patients undergoing RALP by a single physician (DPD at our institution between November 2005 and August 2007 were retrospectively assessed. Surgical pathology records were reviewed for Gleason score, pathologic tumor stage, nodal status, location of prostate cancer within the specimen, extracapsular extension, surgical margin status, presence of perineural invasion, tumor volume, and weight of the surgical specimen. Margin status was determined using surgical specimens only, and not intraoperative frozen sections. All cases in this series were completed using the four-arm da Vinci Robotic System (Intuitive Surgical, Sunnyvale, California. RESULTS: Sixty-one patients had prostate cancer on their final surgical pathology specimens. Pathologic stage T2 and stage T3 patients were 88.7% and 9.7% of all cases, respectively. The pathologic Gleason score was 7 or greater in 62.3%. Our overall positive surgical margin rate was 3.3%. Patients with pathologic T2 and T3 disease had a positive surgical margin rate of 1.8% and 16.7%, respectively. CONCLUSIONS: Our study suggests that RALP can have equal if not better pathologic outcomes compared to open radical prostatectomy even during the initial series of cases. We argue that the learning curve for RALP is shorter than previously thought with respect to oncologic outcomes, and concerns asserting that lack of tactile feedback leads to poor oncologic outcomes are unfounded.

  8. Two-Stage Indicators to Assess Learning Curves for Minimally Invasive Ivor Lewis Esophagectomy.

    Science.gov (United States)

    Wang, Qi; Wu, Zixiang; Chen, Gang; Zhang, Sai; Shen, Gang; Wu, Ming

    2016-10-05

    Background Minimally invasive esophagectomy (MIE) Ivor Lewis has been increasingly performed over the last two decades. To guide the implementation of this technically demanding procedure, a comprehensive assessment of MIE-Ivor Lewis learning curves should include both the general competence to accomplish the procedure and the ability to generate oncological benefits. These objectives are believed to be associated with different phases of the learning curve. Methods A retrospective review of the first 109 patients who underwent MIE-Ivor Lewis by a single qualified surgeon was conducted. Relevant variables were collected and assessed by regression analysis to identify suitable indicators for patient stratification and learning curve assessment. Thereafter, the differential analysis was performed among groups to validate the learning curve model. Results Two variables, intrathoracic gastroesophageal anastomosis time and bilateral recurrent laryngeal nerve (RLN) lymphadenectomy number, which plateaued, respectively, after the 26th and 88th cases, were selected as meaningful indicators to identify different competence levels. Therefore, 109 patients were chronologically subcategorized into three groups (the first 26 MIEs as the early group, the next 62 cases as the middle group, and 21 most recent cases as the late group). Perioperative data were compared between groups with positive results to indicate a three-phase model for a learning curve for MIE-Ivor Lewis. Conclusions An MIE-Ivor Lewis learning curve should include three discrete phases that indicate, successively, unskilled operation (general competence to accomplish, less proficiency), surgical proficiency, and oncological efficacy. Intrathoracic anastomosis time and bilateral RLN lymphadenectomy were identified as suitable indicators delineate the different stages of an MIE-Ivor Lewis learning curve.

  9. Robotic right hemicolectomy: Analysis of 108 consecutive procedures and multidimensional assessment of the learning curve.

    Science.gov (United States)

    Parisi, Amilcare; Scrucca, Luca; Desiderio, Jacopo; Gemini, Alessandro; Guarino, Salvatore; Ricci, Francesco; Cirocchi, Roberto; Palazzini, Giorgio; D'Andrea, Vito; Minelli, Liliana; Trastulli, Stefano

    2017-03-01

    Surgeons tend to view the robotic right colectomy (RRC) as an ideal beginning procedure to gain proficiency in robotic general and colorectal surgery. Nevertheless, oncological RRC, especially if performed with intracorporeal ileocolic anastomosis confectioning, cannot be considered a technically easier procedure. The aim of this study was to assess the learning curve of the RRC performed for oncological purposes and to evaluate its safety and efficacy investigating the perioperative and pathology outcomes in the different learning phases. Data on a consecutive series of 108 patients undergoing RRC with intracorporeal anastomosis between June 2011 and September 2015 at our institution were prospectively collected to evaluate surgical and short-term oncological outcomes. CUSUM (Cumulative Sum) and Risk-Adjusted (RA) CUSUM analysis were performed in order to perform a multidimensional assessment of the learning curve for the RRC surgical procedure. Intraoperative, postoperative and pathological outcomes were compared among the learning curve phases. Based on the CUSUM and RA-CUSUM analyses, the learning curve for RRC could be divided into 3 different phases: phase 1, the initial learning period (1st-44th case); phase 2, the consolidation period (45th-90th case); and phase 3, the mastery period (91th-108th case). Operation time, conversion to open surgery rate and the number of harvested lymph nodes significantly improve through the three learning phases. The learning curve for oncological RRC with intracorporeal anastomosis is composed of 3 phases. Our data indicate that the performance of RRC is safe from an oncological point of view in all of the three phases of the learning curve. However, the technical skills necessary to significantly reduce operative time, conversion to open surgery rate and to significantly improve the number of harvested lymph nodes were achieved after 44 procedures. These data suggest that it might be prudent to start the RRC learning curve

  10. The learning curve of laparoscopic treatment of rectal cancer does not increase morbidity.

    Science.gov (United States)

    Luján, Juan; Gonzalez, Antonio; Abrisqueta, Jesús; Hernandez, Quiteria; Valero, Graciela; Abellán, Israel; Frutos, María Dolores; Parrilla, Pascual

    2014-01-01

    The treatment of rectal cancer via laparoscopy is controversial due to its technical complexity. Several randomized prospective studies have demonstrated clear advantages for the patient with similar oncological results to those of open surgery, although during the learning of this surgical technique there may be an increase in complications and a worse prognosis. Our aim is to analyze how the learning curve for rectal cancer via laparoscopy influences intra- and postoperative results and oncological markers. A retrospective review was conducted of the first 120 patients undergoing laparoscopic surgery for rectal neoplasia. The operations were performed by the same surgical team with a wide experience in the treatment of open colorectal cancer and qualified to perform advanced laparoscopic surgery. We analyzed sex, ASA, tumour location, neoadjuvant treatment, surgical technique, operating time, conversion, postoperative complications, length of hospital stay, number of lymph nodes, stage and involvement of margins. Significant differences were observed with regard to surgical time (224 min in the first group, 204 min in the second group), with a higher rate of conversion in the first group (22.5%) than in the second (11.3%). No significant differences were noted for rate of conservative sphincter surgery, length of hospital stay, post-surgical complications, number of affected/isolated lymph nodes or affected circumferential and distal margins. It is possible to learn this complex surgical technique without compromising the patient's safety and oncological outcome. Copyright © 2013 AEC. Published by Elsevier Espana. All rights reserved.

  11. The learning curve in laparoscopic major liver resection.

    Science.gov (United States)

    Kluger, Michael D; Vigano, Luca; Barroso, Ryan; Cherqui, Daniel

    2013-02-01

    Laparoscopic major hepatectomy remains a relatively rare operation because it is a difficult and technically demanding procedure, and a standard, safe, reproducible technique has not been widely adopted. This is compounded by "major hepatectomy" encompassing multiple different operations each with their own anatomic and procedural considerations. In 2010, we investigated our learning curve for laparoscopic liver resection. We found a significant increase in the number of major hepatectomies performed over a 12-year period, with concurrent reductions in the use of hand-assistance, pedicle clamping, median clamping time, median operative time, blood loss and morbidity. This learning curve was confirmed by a subsequent multinational study. Both hospital and surgeon volume have been shown to affect outcomes, and defining a sufficient number of repetitions before the learning curve plateaus is not easy for laparoscopic major hepatectomy. We recommend that laparoscopic competencies be developed upon a foundation of open liver surgery and that laparoscopic major hepatectomy should only be attempted after competency with less technically complex laparoscopic resections. A center advanced along its institutional learning curve provides the collective expertise necessary for safe patient selection and management. An environment with colleagues willing to share their acquired proficiency allows the surgeon to observe and critique his or her performance against colleagues. Also, the guidance of like-minded surgeons supports technical development and improved outcomes. In conclusion, steady progress can be made along the learning curve through committed practice of increasingly complex tasks and with proper coaching in a high-volume environment.

  12. Learning curve estimation in medical devices and procedures: hierarchical modeling.

    Science.gov (United States)

    Govindarajulu, Usha S; Stillo, Marco; Goldfarb, David; Matheny, Michael E; Resnic, Frederic S

    2017-07-30

    In the use of medical device procedures, learning effects have been shown to be a critical component of medical device safety surveillance. To support their estimation of these effects, we evaluated multiple methods for modeling these rates within a complex simulated dataset representing patients treated by physicians clustered within institutions. We employed unique modeling for the learning curves to incorporate the learning hierarchy between institution and physicians and then modeled them within established methods that work with hierarchical data such as generalized estimating equations (GEE) and generalized linear mixed effect models. We found that both methods performed well, but that the GEE may have some advantages over the generalized linear mixed effect models for ease of modeling and a substantially lower rate of model convergence failures. We then focused more on using GEE and performed a separate simulation to vary the shape of the learning curve as well as employed various smoothing methods to the plots. We concluded that while both hierarchical methods can be used with our mathematical modeling of the learning curve, the GEE tended to perform better across multiple simulated scenarios in order to accurately model the learning effect as a function of physician and hospital hierarchical data in the use of a novel medical device. We found that the choice of shape used to produce the 'learning-free' dataset would be dataset specific, while the choice of smoothing method was negligibly different from one another. This was an important application to understand how best to fit this unique learning curve function for hierarchical physician and hospital data. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  13. Percutaneous Posterolateral Transforaminal Endoscopic Discectomy: Clinical Outcome, Complications, and Learning Curve Evaluation.

    Science.gov (United States)

    Tenenbaum, Shay; Arzi, Harel; Herman, Amir; Friedlander, Alon; Levinkopf, Moshe; Arnold, Paul M; Caspi, Isreal

    2011-12-01

    Ongoing technological development combined with better understanding of endoscopic anatomy has made posterolateral endoscopic discectomy an appealing surgical option for the management of herniated lumbar disc. We evaluated clinical outcomes, complication rates, and surgical learning curve with the percutaneous posterolateral transforaminal endoscopic discectomy technique (PPTED). PPTED was performed on 150 patients from 2004 to 2008. And 124 patients were available for follow-up. Data regarding pain, postoperative complications, neurological status, operation time, and subjective patient satisfaction were recorded. A satisfactory clinical outcome as reflected in the VAS (mean 3.6) and ODI improvement (mean 21%) scores was reported; 20.9% of the patients required additional surgery. Learning curve assessment showed a significant difference (p = 0.043) for fewer revision surgeries as surgeons became more experienced. Patients who had endoscopic discectomy as a primary surgery achieved significantly lower VAS (p = 0.04) and ODI improvement (p = 0.004) scores compared with patients having transforaminal endoscopic discectomy as revision surgery. The complication rate was 1.6%, including one case of post-surgery hypoesthesia and one deep wound infection. The percutaneous posterolateral transforaminal endoscopic discectomy technique has a satisfactory clinical outcome with a low complication rate. Results for endoscopic surgery for revision or recurrent disc herniation are comparable to those of open revision surgery; the steep learning curve can be overcome with training and suitable patient selection.

  14. Surgical education and adult learning: Integrating theory into practice.

    Science.gov (United States)

    Rashid, Prem

    2017-01-01

    Surgical education continues to evolve from the master-apprentice model. Newer methods of the process need to be used to manage the dual challenges of educating while providing safe surgical care. This requires integrating adult learning concepts into delivery of practical training and education in busy clinical environments. A narrative review aimed at outlining and integrating adult learning and surgical education theory was undertaken. Additionally, this information was used to relate the practical delivery of surgical training and education in day-to-day surgical practice. Concepts were sourced from reference material. Additional material was found using a PubMed search of the words: 'surgical education theory' and 'adult learning theory medical'. This yielded 1351 abstracts, of which 43 articles with a focus on key concepts in adult education theory were used. Key papers were used to formulate structure and additional cross-referenced papers were included where appropriate. Current concepts within adult learning have a lot to offer when considering how to better deliver surgical education and training. Better integration of adult learning theory can be fruitful. Individual teaching surgical units need to rethink their paradigms and consider how each individual can contribute to the education experience. Up skilling courses for trainers can do much to improve the delivery of surgical education. Understanding adult learning concepts and integrating these into day-to-day teaching can be valuable.

  15. Surgical education and adult learning: Integrating theory into practice

    Science.gov (United States)

    Rashid, Prem

    2017-01-01

    Surgical education continues to evolve from the master-apprentice model. Newer methods of the process need to be used to manage the dual challenges of educating while providing safe surgical care. This requires integrating adult learning concepts into delivery of practical training and education in busy clinical environments. A narrative review aimed at outlining and integrating adult learning and surgical education theory was undertaken. Additionally, this information was used to relate the practical delivery of surgical training and education in day-to-day surgical practice. Concepts were sourced from reference material. Additional material was found using a PubMed search of the words: ‘surgical education theory’ and ‘adult learning theory medical’. This yielded 1351 abstracts, of which 43 articles with a focus on key concepts in adult education theory were used. Key papers were used to formulate structure and additional cross-referenced papers were included where appropriate. Current concepts within adult learning have a lot to offer when considering how to better deliver surgical education and training. Better integration of adult learning theory can be fruitful. Individual teaching surgical units need to rethink their paradigms and consider how each individual can contribute to the education experience. Up skilling courses for trainers can do much to improve the delivery of surgical education. Understanding adult learning concepts and integrating these into day-to-day teaching can be valuable.

  16. Conversion during thoracoscopic lobectomy: related factors and learning curve impact.

    Science.gov (United States)

    Smith, David E; Dietrich, Agustin; Nicolas, Matias; Da Lozzo, Alejandro; Beveraggi, Enrique

    2015-12-01

    Video-assisted thoracoscopic surgery (VATS) lobectomy has become a standard procedure for lung cancer treatment. Conversion-related factors and learning curve impacts, were poorly described. The aim of this study was to review the reasons and related factor for conversion in VATS lobectomy and the impact on this of the surgeon's learning curve. From June 2009 to May 2014, 154 patients who underwent a VATS lobectomy were included in our study. Patients' characteristics, pathology background, operative times, overall length of stay, overall morbidity and type of major complications were recorded for all patients and compared between non converted (n = 133) and converted (n = 21) patients. To evaluate surgeon's learning curve, we analyzed rates and causes of conversion in the first period (first 77 patients) and in the last period (78-154 patients). Patients characteristics were similar between converted and non-converted groups. Patients who were converted to open thoracotomy presented more frecuently tumors >3 cms (P = 0.02). The average of operative times and the length of stay were not significantly different between groups. Overall morbidity and major complications were also similar in both groups. There were no impact of surgeon's learning curve in overall rate conversion in both groups. Emergency conversion was always secondary to vascular accidents, all in the first group (p = 0.059). Surgeons should be expecting to perform a conversion to a thoracotomy in patients who present in preoperative studies, tumors greater than 3 cms. Learning curve only affected the emergency conversion, occurred all in the first half of our series.

  17. Is the Latarjet procedure risky? Analysis of complications and learning curve.

    Science.gov (United States)

    Dauzère, Florence; Faraud, Amélie; Lebon, Julie; Faruch, Marie; Mansat, Pierre; Bonnevialle, Nicolas

    2016-02-01

    The purpose of this study was to analyse the learning curve and complication rate of the open Latarjet procedure. The first 68 Latarjet procedures performed by a single surgeon for chronic anterior shoulder instability were reviewed retrospectively. The standard open surgical technique was followed faithfully during each procedure. Post-operative complications were taken from patient medical records. Post-operative evaluation consisted of clinical and radiological assessments. The rate of early (Latarjet procedure remains low. A surgeon's experience significantly affects the surgery duration and the occurrence of early complications. The main radiological complication is partial lysis of the bone block. After a short learning curve, the clinical outcomes of the Latarjet procedure appear to be satisfactory and reproducible. IV.

  18. Learning from the learning curve in total hip resurfacing: a radiographic analysis.

    NARCIS (Netherlands)

    Witjes, S.; Smolders, J.M.; Beaule, P.E.; Pasker, P.; Susante, J.L.C. van

    2009-01-01

    BACKGROUND: Operation of hip resurfacing prosthesis is a technically demanding procedure accompanied by a learning curve. To our knowledge no objective data on this learning curve are available in the literature. METHODS: For the first 40 resurfacing hip prostheses implanted by a single-surgeon radi

  19. Learning curve-based scheduling in customized assembly lines

    Directory of Open Access Journals (Sweden)

    Michel J. Anzanello

    2011-09-01

    Full Text Available Mass customization implies in large variety of product models and small lot sizes. Human-based activities are highly affected by the learning process as a new model is put into production. That makes estimation of lot processing times difficult and jeopardizes the efficiency of scheduling techniques. The method proposed in this paper integrates information from learning curve modeling and scheduling heuristics, aiming at minimizing the completion time of jobs to be processed. Lot processing time is estimated by means of learning curve modeling and then used in scheduling heuristics for the unrelated parallel workers problem. The completion time generated by the recommended heuristic, determined through simulation, deviates 4.9% from the optimal sequence and yields good work balance among teams of workers. The heuristic is demonstrated in a shoe manufacturing process.

  20. Robotic-assisted radical prostatectomy learning curve for experienced laparoscopic surgeons: does it really exist?

    Science.gov (United States)

    Tobias-Machado, Marcos; Mitre, Anuar Ibrahim; Rubinstein, Mauricio; da Costa, Eduardo Fernandes; Hidaka, Alexandre Kyoshi

    2016-01-01

    ABSTRACT Background Robotic-assisted radical prostatectomy (RALP) is a minimally invasive procedure that could have a reduced learning curve for unfamiliar laparoscopic surgeon. However, there are no consensuses regarding the impact of previous laparoscopic experience on the learning curve of RALP. We report on a functional and perioperative outcome comparison between our initial 60 cases of RALP and last 60 cases of laparoscopic radical prostatectomy (LRP), performed by three experienced laparoscopic surgeons with a 200+LRP cases experience. Materials and Methods Between January 2010 and September 2013, a total of 60 consecutive patients who have undergone RALP were prospectively evaluated and compared to the last 60 cases of LRP. Data included demographic data, operative duration, blood loss, transfusion rate, positive surgical margins, hospital stay, complications and potency and continence rates. Results The mean operative time and blood loss were higher in RALP (236 versus 153 minutes, p<0.001 and 245.6 versus 202ml p<0.001). Potency rates at 6 months were higher in RALP (70% versus 50% p=0.02). Positive surgical margins were also higher in RALP (31.6% versus 12.5%, p=0.01). Continence rates at 6 months were similar (93.3% versus 89.3% p=0.43). Patient’s age, complication rates and length of hospital stay were similar for both groups. Conclusions Experienced laparoscopic surgeons (ELS) present a learning curve for RALP only demonstrated by longer operative time and clinically insignificant blood loss. Our initial results demonstrated similar perioperative and functional outcomes for both approaches. ELS were able to achieve satisfactory oncological and functional results during the learning curve period for RALP. PMID:27136471

  1. Robotic partial nephrectomy - Evaluation of the impact of case mix on the procedural learning curve.

    Science.gov (United States)

    Roman, A; Ahmed, K; Challacombe, B

    2016-05-01

    Although Robotic partial nephrectomy (RPN) is an emerging technique for the management of small renal masses, this approach is technically demanding. To date, there is limited data on the nature and progression of the learning curve in RPN. To analyse the impact of case mix on the RPN LC and to model the learning curve. The records of the first 100 RPN performed, were analysed at our institution that were carried out by a single surgeon (B.C) (June 2010-December 2013). Cases were split based on their Preoperative Aspects and Dimensions Used for an Anatomical (PADUA) score into the following groups: 6-7, 8-9 and >10. Using a split group (20 patients in each group) and incremental analysis, the mean, the curve of best fit and R(2) values were calculated for each group. Of 100 patients (F:28, M:72), the mean age was 56.4 ± 11.9 years. The number of patients in each PADUA score groups: 6-7, 8-9 and >10 were 61, 32 and 7 respectively. An increase in incidence of more complex cases throughout the cohort was evident within the 8-9 group (2010: 1 case, 2013: 16 cases). The learning process did not significantly affect the proxies used to assess surgical proficiency in this study (operative time and warm ischaemia time). Case difficulty is an important parameter that should be considered when evaluating procedural learning curves. There is not one well fitting model that can be used to model the learning curve. With increasing experience, clinicians tend to operate on more difficult cases. Copyright © 2016 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.

  2. The Predictive Value of Ultrasound Learning Curves Across Simulated and Clinical Settings

    DEFF Research Database (Denmark)

    Madsen, Mette E; Nørgaard, Lone N; Tabor, Ann

    2017-01-01

    OBJECTIVES: The aim of the study was to explore whether learning curves on a virtual-reality (VR) sonographic simulator can be used to predict subsequent learning curves on a physical mannequin and learning curves during clinical training. METHODS: Twenty midwives completed a simulation-based tra......OBJECTIVES: The aim of the study was to explore whether learning curves on a virtual-reality (VR) sonographic simulator can be used to predict subsequent learning curves on a physical mannequin and learning curves during clinical training. METHODS: Twenty midwives completed a simulation...

  3. Concentrated photovoltaics system costs and learning curve analysis

    Science.gov (United States)

    Haysom, Joan E.; Jafarieh, Omid; Anis, Hanan; Hinzer, Karin

    2013-09-01

    An extensive set of costs in /W for the installed costs of CPV systems has been amassed from a range of public sources, including both individual company prices and market reports. Cost reductions over time are very evident, with current prices for 2012 in the range of 3.0 ± 0.7 /W and a predicted cost of 1.5 /W for 2020. Cost data is combined with deployment volumes in a learning curve analysis, providing a fitted learning rate of either 18.5% or 22.3% depending on the methodology. This learning rate is compared to that of PV modules and PV installed systems, and the influence of soft costs is discussed. Finally, if an annual growth rate of 39% is assumed for deployed volumes, then, using the learning rate of 20%, this would predict the achievement of a cost point of 1.5 /W by 2016.

  4. Learning curve for paramedic endotracheal intubation and complications

    OpenAIRE

    Toda, J; Toda, AA; Arakawa, J

    2013-01-01

    Background Pre-hospital laryngoscopic endotracheal intubation (ETI) is potentially a life-saving procedure but is a technique difficult to acquire. This study aimed to obtain a recommendation for the number of times ETI should be practiced by constructing the learning curve for endotracheal intubation by paramedics, as well as to report the change in the frequency of complications possibly associated with intubation over the training period. Methods Under training c...

  5. The Learning Curve for a Fetal Cardiac Intervention Team

    OpenAIRE

    Emery, Stephen P.; Jacqueline Kreutzer; McCaffrey, Frances M.; Fredrick S. Sherman; Simhan, Hyagriv N; Keller, Bradley B.

    2010-01-01

    Objectives. Multiple technical difficulties are encountered when a multidisciplinary team of subspecialists begins a minimally-invasive fetal cardiac interventional program. We describe the learning curve. Study Design. Ten pregnant sheep underwent ultrasound-guided balloon valvuloplasty of the aortic valve. Team members and their roles remained constant through the trial. The time between needle insertion and entrance of the left ventricle at the aortic root was recorded. F-test was used to ...

  6. A New Proposal for Learning Curve of TEP Inguinal Hernia Repair: Ability to Complete Operation Endoscopically as a First Phase of Learning Curve

    Directory of Open Access Journals (Sweden)

    Mustafa Hasbahceci

    2014-01-01

    Full Text Available Background. The exact nature of learning curve of totally extraperitoneal inguinal hernia and the number required to master this technique remain controversial. Patients and Methods. We present a retrospective review of a single surgeon experience on patients who underwent totally extraperitoneal inguinal hernia repair. Results. There were 42 hernias (22 left- and 20 right-sided in 39 patients with a mean age of 48.8±15.1 years. Indirect, direct, and combined hernias were present in 18, 12, and 12 cases, respectively. The mean operative time was 55.1±22.8 minutes. Peritoneal injury occurred in 9 cases (21.4%. Conversion to open surgery was necessitated in 7 cases (16.7%. After grouping of all patients into two groups as cases between 1–21 and 22–42, it was seen that the majority of peritoneal injuries (7 out of 9, 77.8%, P=0.130 and all conversions (P=0.001 occurred in the first 21 cases. Conclusions. Learning curve of totally extraperitoneal inguinal hernia repair can be divided into two consequent steps: immediate and late. At least 20 operations are required for gaining anatomical knowledge and surgical pitfalls based on the ability to perform this operation without conversion during immediate phase.

  7. E-learning in surgical education and training.

    Science.gov (United States)

    Larvin, Mike

    2009-03-01

    For most surgeons and surgical educators, e-learning is relatively new and confusing. This article attempts to explain the key concepts behind e-learning, as well as its benefits and risks. E-learning has become a fixed feature within Higher and Professional Education and has been prioritized by Universities around the world, as well as all six Surgical Royal Colleges. Trainees have grown up with virtual learning environments and expect similar provision for their postgraduate studies, but have a greater need for basic science learning. Dispersal of trainees across duty rotas and geographically makes e-learning more attractive, but preserving peer and trainer communication is as important as content. Recent changes in surgical education and training have also made electronic and distance learning more attractive than previously. Initial work by the Colleges is now being evaluated and important lessons have emerged. The UK Department of Health has made medical e-learning a priority and it is now the largest e-learning provider in Europe. Changes in the World Wide Web, with a shift to more social-networking activity in education and to web-based delivery to small, ubiquitous portable devices will increase opportunities for surgical e-learning.

  8. [Learning curve and his consequences in laparoscopic antireflux surgery].

    Science.gov (United States)

    Cristian, D; Sgarbură, Olivia; Jitea, N; Burcoş, T

    2005-01-01

    The laparoscopic fundoplication became the gold standard of the laparoscopic antireflux surgery (LARS). Our aim is to indicate the evolution of the learning curve as well as its consequences on the patient's outcome. We studied the gastro-esophageal reflux (GER) cases treated laparoscopically in Colţea University Hospital throughout 6 years. We gathered a group of 40 patients with an average age of 54, 57 years and a sex ratio F:M = 1.67. The patients had either a simple GER disease, small and medium hiatal hernias (21 cases) or giant hiatal hernias (GHH--19 cases). Two equal groups resulted: group 1 consisted of the first 20 patients operated from 1999 to 2002, group 2 consisted of the rest of the patients. Operating time, hospital time, complication rate and postoperatory endoscopy were compared. The average of the operating time was calculated. For giant hiatal hernias, a separate average was also taken into account. The total operating time for GER, small and medium hiatal hernias was 115 min in group 1 and 80 min in group 2 meanwhile for GHH it was 143 min vs. 130 min. The average operatory time was 129 min vs. 105 min. All these differences were statistically significant but there were no differences concerning complication rate and post-operatory endoscopy. Although the learning of the laparoscopic fundoplication requires practice, the learning curve does not have influence on the patients' outcome.

  9. [Is local bone graft sufficient to maintain the surgical correction in adolescent idiopathic scoliosis curves?].

    Science.gov (United States)

    Mardomingo, A; Sánchez-Mariscal, F; Alvarez, P; Pizones, J; Zúñica, L; Izquierdo, E

    2013-01-01

    The purpose of this study was to compare postoperative clinical and radiological results in adolescent idiopathic scoliosis curves treated by posterior arthrodesis using autogenous bone graft from iliac crest (CI) versus only local autograft bone (HL). A retrospective matched cohort study was conducted on 73 patients (CI n=37 and HL n=36) diagnosed with adolescent idiopathic scoliosis and treated surgically by posterior arthrodesis. The mean post-operative follow-up was 126 months in the CI group vs. 66 months in the HL group. The radiographic data collected consisted of preoperative, postoperative, and final follow-up antero-posterior and lateral full-length radiographs. Loss of correction and quality of arthrodesis were evaluated by comparing the scores obtained from the Spanish version of the SRS-22 questionnaire. There were significant differences in the post-operative results as regards the correction of the Cobb angle of the main curve (HL 61 ± 15% vs. CI 51 ± 14%, P<.004), however a greater loss of correction was found in the local bone group (CI 4.5 ± 7.3° vs. HL 8.5 ± 6.3°, P=.02). There were no significant differences as regards the correction of the Cobb angle of the main curve at the end of follow-up. There were no clinical differences between the two groups in the SRS-22 scores. At 5 years of follow-up, there was a statistically significant greater loss of radiographic correction at the end of final follow-up in the local bone graft group. However clinical differences were not observed as regards the SRS-22 scores. Copyright © 2013 SECOT. Published by Elsevier Espana. All rights reserved.

  10. Learning curve evaluation using cumulative summation analysis-a clinical example of pediatric robot-assisted laparoscopic pyeloplasty.

    Science.gov (United States)

    Cundy, Thomas P; Gattas, Nicholas E; White, Alan D; Najmaldin, Azad S

    2015-08-01

    The cumulative summation (CUSUM) method for learning curve analysis remains under-utilized in the surgical literature in general, and is described in only a small number of publications within the field of pediatric surgery. This study introduces the CUSUM analysis technique and applies it to evaluate the learning curve for pediatric robot-assisted laparoscopic pyeloplasty (RP). Clinical data were prospectively recorded for consecutive pediatric RP cases performed by a single-surgeon. CUSUM charts and tests were generated for set-up time, docking time, console time, operating time, total operating room time, and postoperative complications. Conversions and avoidable operating room delay were separately evaluated with respect to case experience. Comparisons between case experience and time-based outcomes were assessed using the Student's t-test and ANOVA for bi-phasic and multi-phasic learning curves respectively. Comparison between case experience and complication frequency was assessed using the Kruskal-Wallis test. A total of 90 RP cases were evaluated. The learning curve transitioned beyond the learning phase at cases 10, 15, 42, 57, and 58 for set-up time, docking time, console time, operating time, and total operating room time respectively. All comparisons of mean operating times between the learning phase and subsequent phases were statistically significant (P=learning curve evaluation and outcome quality monitoring. In applying this statistical technique to the largest reported single surgeon series of pediatric RP, we demonstrate numerous distinctly shaped learning curves and well-defined learning phase transition points. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. The Learning Curve for a Fetal Cardiac Intervention Team

    Directory of Open Access Journals (Sweden)

    Stephen P. Emery

    2010-01-01

    Full Text Available Objectives. Multiple technical difficulties are encountered when a multidisciplinary team of subspecialists begins a minimally-invasive fetal cardiac interventional program. We describe the learning curve. Study Design. Ten pregnant sheep underwent ultrasound-guided balloon valvuloplasty of the aortic valve. Team members and their roles remained constant through the trial. The time between needle insertion and entrance of the left ventricle at the aortic root was recorded. F-test was used to assess significance (P≤.05. Results. The time required to accurately position the needle tip at the aortic root decreased significantly over the course of the trial, from 12 minutes with the first attempt to one minute with the last (P=.003. Conclusion. A significant learning curve is encountered when a multidisciplinary team begins a minimally-invasive fetal cardiac intervention program. However, technical proficiency can be achieved with practice. Institutions interested in developing such a program should consider practice in an animal model before proceeding to the human fetus.

  12. Transcatheter closure of patent ductus arteriosus: Evaluating the effect of the learning curve on the outcome

    Directory of Open Access Journals (Sweden)

    Azhar Ahmad

    2009-01-01

    Full Text Available Background and Objectives : Initial experience with transcatheter closure of patent ductus arteriosus (PDA using detachable coils and Amplatzer duct occluder devices is reported. We evaluated the outcome, complications, and influence of the learning curve, and also assessed the need of surgical backup for such interventional procedures. Methods: From January 2000 to December 2004, 121 patients underwent transcatheter closure of PDA. Aortic angiogram was performed to evaluate the size, position, and shape of the duct for appropriately choosing the occluder device type and size. A second aortic angiogram was performed 10 minutes after device deployment. Echocardiography was repeated at intervals of 24 hours, then at 1, 3, and 6 months after the procedure to assess complications. Stepwise multiple regression analysis was used to assess the role of experience in improving the outcome of the procedure. Results: Of 121 cases, four patients had pulmonary artery embolization of the occluder device which was successfully retrieved in the catheterization laboratory, while two others had embolization that required surgical intervention. Four patients had temporary residual leak, nine had protrusion of the device into the aorta without significant Doppler pressure gradient or hemolysis on follow-up, and five had partial hemodynamically insignificant obstruction to the left pulmonary artery. Statistical analysis showed that the effect of the learning curve and experience was responsible for 93% improvement in the procedural outcome over the five-year study period. Conclusion: Transcatheter occlusion of PDA is safe and effective alternative to surgery. Complications occurred in those with unfavorable duct anatomy and with the use of multiple coils. Surgical backup was important for such interventional procedures. Experience played a major role in the proper choice of device type and size which greatly influenced the outcome of the procedure.

  13. The learning curve of robot-assisted laparoscopic fundoplication in children: a prospective evaluation and CUSUM analysis.

    Science.gov (United States)

    Cundy, Thomas P; Rowland, Simon P; Gattas, Nicholas E; White, Alan D; Najmaldin, Azad S

    2015-06-01

    Fundoplication is a leading application of robotic surgery in children, yet the learning curve for this procedure (RF) remains ill-defined. This study aims to identify various learning curve transition points, using cumulative summation (CUSUM) analysis. A prospective database was examined to identify RF cases undertaken during 2006-2014. Time-based surgical process outcomes were evaluated, as well as clinical outcomes. A total of 57 RF cases were included. Statistically significant transitions beyond the learning phase were observed at cases 42, 34 and 37 for docking, console and total operating room times, respectively. A steep early learning phase for docking time was overcome after 12 cases. There were three Clavien-Dindo grade ≥ 3 complications, with two patients requiring redo fundoplication. We identified numerous well-defined learning curve trends to affirm that experience confers significant temporal improvements. Our findings highlight the value of the CUSUM method for learning curve evaluation. Copyright © 2014 John Wiley & Sons, Ltd.

  14. The Learning Curve of Transareola Single-site Laparoendoscopic Thyroidectomy: CUSUM Analysis of a Single Surgeon’s Experience

    Science.gov (United States)

    Zhu, Guanghui; Zhang, Xueli; Tang, Zhiqiang; Tan, Zhanhai; Chen, Jianrong

    2016-01-01

    Background: Transareola single-site laparoendoscopic thyroidectomy (TASSET) is a rapidly advancing minimally invasive procedure. The purpose of this study was to evaluate the learning curve for TASSET. Subjects and Methods: Forty-five consecutive patients were prospectively divided into group 1 (initial phase), group 2 (intermediate phase), and group 3 (advanced phase) according to their surgical order (15 patients in each group). The operative time, operative blood loss, duration of hospital stay, postoperative pain, and postoperative complications were compared using phases. Results: Statistically significant differences were observed in the different learning phases, among operative time (P<0.05), operative blood loss (P<0.05), hospital stay (P<0.05), and postoperative pain (P<0.05). The postoperative complication rate was low (3/45). Conclusions: Learning curve of the TASSET are improved synchronized at different phases and technical indicators. The establishment of operative space take longer time to skilled master. PMID:27552376

  15. Comparison of arthroscopic and open Latarjet with a learning curve analysis.

    Science.gov (United States)

    Cunningham, G; Benchouk, S; Kherad, O; Lädermann, A

    2016-02-01

    To compare arthroscopic and open Latarjet performed by a single shoulder surgeon with learning curve analysis A comparative and learning curve analysis was carried out on a prospectively gathered database of 2 consecutive series of patients treated with arthroscopic and open Latarjet procedures performed by a single shoulder surgeon between 2008 and 2014. The database included patient characteristics, ISIS scores, operative time, intra- and postoperative complications, graft and screws positioning, as well as pre- and postoperative Walch-Duplay scores. Sixty-four patients were included in the study, 28 in the arthroscopic group and 36 in the open group with similar age, sex ratio and preoperative ISIS score. Operative time was significantly higher in the arthroscopic group (146 versus 81 min, p = 0.001), and although no intra-operative complications were recorded in either group, there were significantly more postoperative complications in the arthroscopic group (29 vs. 11 %, p = 0.03). Screw placement was more accurate in the open group, and postoperative Walch-Duplay score did not show any significant difference between the groups (88 points in the arthroscopic group and 91 points in the open group). The arthroscopic Latarjet learning curve analysis showed that the need for conversion ceased after the first 10 patients and that surgical time came close to that of open procedure after 20 procedures. In this study, 10 arthroscopic Latarjet procedures were needed to overcome the need for conversion, and 20 procedures to achieve equal operating time to the open technique. Even though functional outcome and patient satisfaction were similar in both techniques, complications, screw placement inaccuracy, persistent apprehension and recurrences still remain higher with the arthroscopic technique. Retrospective comparative analysis, Level III.

  16. The Surgical Scrub. Instructor's Packet. Learning Activity Package.

    Science.gov (United States)

    Runge, Lillian

    This instructor's packet accompanies the learning activity package (LAP) on the surgical scrub. Contents included in the packet are a time sheet, suggested uses for the LAP, an instruction sheet, final LAP reviews, a final LAP review answer key, a student performance checklist, suggested activities, an additional resources list, and student…

  17. Documenting a learning curve and test-retest reliability of two tasks on a virtual reality training simulator in laparoscopic surgery.

    Science.gov (United States)

    Hogle, Nancy J; Briggs, William M; Fowler, Dennis L

    2007-01-01

    Virtual reality simulators are a component of the armamentarium for training surgical residents. No one knows exactly how to incorporate virtual reality simulators into a curriculum. The purpose of this study was to document and show the learning curve and test-retest reliability of 2 tasks on a virtual reality-training simulator (LapSim; Surgical Science, Göteborg, Sweden) in laparoscopic surgery. Twenty-nine medical students participated in 8 iterations of 7 virtual reality tasks ("camera navigation" (CN), "instrument navigation," "coordination," "grasping," "lifting and grasping" (LG), "cutting," and "clip applying") Learning curves for each outcome variable of the CN and LG tasks were generated. Using ANOVA, we evaluated the differences between each score from attempt number 7 to attempt number 8 to document test-retest reliability. A plateau in the learning curve occurred within 8 sessions for CN misses, CN tissue damage, CN maximum damage, and LG maximum damage. Over the course of 8 sessions, a plateau in the learning curve was nearly reached for CN time, CN drift, CN path, CN angular path, and LG left and right path. The following variables had a downward trend to the mean learning curve over 8 sessions, but they did not reach a plateau: LG time, LG left and right miss, LG left and right angular path, and LG tissue damage. Using the LapSim virtual reality simulator, we documented a learning curve and test-retest reliability for each outcome variable for CN and LG for rank novices. The modeling of the general learning curve is useful in designing training program. These results may be important in developing standards for technical evaluation in a surgical training curriculum.

  18. [Individual learning curve for radical robot-assisted prostatectomy based on the example of three professionals working in one clinic].

    Science.gov (United States)

    Rasner, P I; Pushkar', D Iu; Kolontarev, K B; Kotenkov, D V

    2014-01-01

    The appearance of new surgical technique always requires evaluation of its effectiveness and ease of acquisition. A comparative study of the results of the first three series of successive robot-assisted radical prostatectomy (RARP) performed on at time by three surgeons, was conducted. The series consisted of 40 procedures, and were divided into 4 groups of 10 operations for the analysis. When comparing data, statistically significant improvement of intra- and postoperative performance in each series was revealed, with increase in the number of operations performed, and in each subsequent series compared with the preceding one. We recommend to perform the planned conversion at the first operation. In our study, previous laparoscopic experience did not provide any significant advantages in the acquisition of robot-assisted technology. To characterize the individual learning curve, we recommend the use of the number of operations that the surgeon looked in the life-surgery regimen and/or in which he participated as an assistant before his own surgical activity, as well as the indicator "technical defect". In addition to the term "individual learning curve", we propose to introduce the terms "surgeon's individual training phase", and "clinic's learning curve".

  19. Surgical resident learning styles have changed with work hours.

    Science.gov (United States)

    Quillin, Ralph C; Cortez, Alexander R; Pritts, Timothy A; Hanseman, Dennis J; Edwards, Michael J; Davis, Bradley R

    2016-01-01

    The Accreditation Council for Graduate Medical Education instituted the 80-h workweek for residency programs in 2003. This presented a unique challenge for surgery residents who must acquire a medical and technical knowledge base during training. Therefore, learning should be delivered in an environment congruent with an individual's learning style. In this study, we evaluated the learning styles of general surgery residents to determine how learning styles changed after the implementation to the 80-h workweek. Kolb learning style inventory was taken by general surgery residents at the University of Cincinnati's Department of Surgery, and results from 1999-2012 were analyzed. Statistical analysis was performed using the chi-squared, logistic regression and Wilcoxon rank-sum test. Significance was defined as a P value of learning styles after the institution of the 80-h workweek to converging (43.9%) and accommodating (40.4%, P learning. This change paralleled the transition to a more team-based approach to patient care with the implementation of the 80-h workweek. These findings are important for surgical educators to consider in the development of surgical resident curriculum. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Using Dragon Curves To Learn about Length and Area.

    Science.gov (United States)

    Smith, Lyle R.

    1999-01-01

    Utilizes dragon curves which are made with three tiles and can be used to create fascinating patterns to help students understand the concepts of length, area, and perimeter of regions as defined by dragon curves. (ASK)

  1. Developments in Interpreting Learning Curves and Applications to Energy Technology Policy

    Energy Technology Data Exchange (ETDEWEB)

    Van der Zwaan, B.C.C. [Energy research Centre of the Netherlands, ECN Policy Studies, Petten (Netherlands); Wene, C.O. [Wenergy, Lund (Sweden)

    2011-06-15

    The book 'Learning Curves: Theory, Models, and Applications' first draws a learning map that shows where learning is involved within organizations, then examines how it can be sustained, perfected, and accelerated. The book reviews empirical findings in the literature in terms of different sources for learning and partial assessments of the steps that make up the actual learning process inside the learning curve. Chapter 23 on 'Developments in Interpreting Learning Curves and Applications to Energy Technology Policy' is written by Bob van der Zwaan and Clas-Otto Wene. In this chapter they provide some interpretations of experience and learning curves starting from three different theoretical platforms. These interpretations are aimed at explaining learning rates for different energy technologies. The ultimate purpose is to find the role that experience and learning curves can legitimately play in designing efficient government deployment programs and in analyzing the implications of different energy scenarios. The 'Component Learning' section summarizes recent work by the authors that focuses on the disaggregation of technologies in their respective components and argues that traditional learning for overall technology should perhaps be replaced by a phenomenology that recognizes learning for individual components. The 'Learning and Time' section presents an approach that departs more strongly from the conventional learning curve methodology, by suggesting that exponential growth and progress may be the deeper underlying processes behind observed learning-by-doing. Contrary to this view, the cybernetic approach presented in the 'Cybernetic Approach' section sees learning curves as expressing a fundamental property of organizations in competitive markets and applies the findings from second order cybernetics to calculate the learning rates for operationally closed systems. All three interpretations find empirical

  2. Surgical Navigation

    DEFF Research Database (Denmark)

    Azarmehr, Iman; Stokbro, Kasper; Bell, R. Bryan

    2017-01-01

    were identified in the field of traumatology. Treatment of complex orbital fractures was considerably improved by the use of SN compared with traditionally treated control groups. Conclusions: SN seems to be a very promising addition to the surgical toolkit. Planning details of the surgical procedure...... in a 3-dimensional virtual environment and execution with real-time guidance can significantly improve precision. Among factors to be considered are the financial investments necessary and the learning curve....

  3. The learning curve of selective salpingography and tubal catheterization.

    Science.gov (United States)

    Papaioannou, Spyros; Afnan, Masood; Girling, Alan J; Ola, Bolarinde; Hammadieh, Nehed; Coomarasamy, Aravinthan; Sharif, Kaldoun

    2002-05-01

    To determine the effect of increasing experience in fluoroscopically guided selective salpingography and tubal catheterization on radiation doses and screening times, thus establishing a learning curve for the procedure. Retrospective case note analysis. IVF center of an academic teaching hospital. Three hundred sixty-six patients with infertility seen over 3.5 years. Fluoroscopically guided selective salpingography and tubal catheterization. Reductions in radiation doses and screening times for different categories of selective salpingography and tubal catheterization, expressed as percentage reductions during the study period and reductions per 10 procedures. During the study period, The median dose of radiation decreased by 62.6%-71.9%, and the median screening time declined by 61.5%-78.5%. Reductions per 10 procedures were 2.5%-4.2% and 2.7%-5%, respectively. Significant reductions in radiation doses and screening times start early in a clinical team's practice of selective salpingography and tubal catheterization and continue even as trainees are added to the pool of operators.

  4. Training programs influence in the learning curve of laparoscopic gastric bypass for morbid obesity: a systematic review.

    Science.gov (United States)

    Sánchez-Santos, Raquel; Estévez, Sergio; Tomé, Catherine; González, Sonia; Brox, Antonia; Nicolás, Raul; Crego, Rosario; Piñón, Miguel; Masdevall, Carles; Torres, Antonio

    2012-01-01

    The makeup of a new surgical bariatric team may be associated with a higher number of postoperative complications due to the learning curve. The aim of this study was to evaluate the outcomes during the learning curve of laparoscopic gastric bypass (LGBP) depending on surgeons' training. A systematic approach was used to review studies from the Pubmed, Embase (Ovid), Cancer Lit, Biomes Central via Scirus, Current Contens (ISI), and Web of Science (SCI) databases. Two reviewers independently screened all titles/abstracts and included/excluded studies based on full copies of manuscripts. The outcomes included were: specific training of the surgeon, postoperative complications (leaks, occlusion, hemorrhage, pneumonia, etc.), mortality, and surgical technique. One reviewer put data onto an Excel spreadsheet. Statistical analysis was performed with weighted linear regression. We identified 448 citations, of which 120 abstract and 50 full-text publications were reviewed. Fourteen papers were selected. Data from 1,848 patients were included. Eighteen different surgeons were analyzed during their learning curve (including the first author of this study). Surgeons were divided into two groups: (1) without formal laparoscopic bariatric training (13 surgeons) and (2) with formal laparoscopic bariatric training (five surgeons). Postoperative complications were more frequent in group 1: 18.1% (± 7.6) vs. 7.7% (± 1.96, p = 0.046); also, mortality was more frequent in group 1: 0.57% (± 0.87) vs. 0% (p = 0.05). An appropriated training in laparoscopic bariatric surgery contributes to a significant reduction in postoperative complications and mortality during the learning curve of LGBP.

  5. Teaching Learning Curves in an Undergraduate Economics or Operations Management Course

    Science.gov (United States)

    Naidu, Jaideep T.; Sanford, John F.

    2012-01-01

    Learning Curves has its roots in economics and behavioral psychology. Learning Curves theory has several business applications and is widely used in the industry. As faculty of Operations Management courses, we cover this topic in some depth in the classroom. In this paper, we present some of our teaching methods and material that have helped us…

  6. The Quantitative Evaluation of Functional Neuroimaging Experiments: Mutual Information Learning Curves

    DEFF Research Database (Denmark)

    Kjems, Ulrik; Hansen, Lars Kai; Anderson, Jon

    2002-01-01

    Learning curves are presented as an unbiased means for evaluating the performance of models for neuroimaging data analysis. The learning curve measures the predictive performance in terms of the generalization or prediction error as a function of the number of independent examples (e.g., subjects...

  7. Learning curve of transvaginal ultrasound for the diagnosis of endometriomas assessed by the cumulative summation test (LC-CUSUM).

    Science.gov (United States)

    Bazot, Marc; Daraï, Emile; Biau, David J; Ballester, Marcos; Dessolle, Lionel

    2011-01-01

    A specific statistical tool (the cumulative summation test for learning curve or LC-CUSUM) was used to monitor the learning curve of four trainees for the diagnosis of endometriomas by transvaginal ultrasound. A large intertrainee variability in the learning curves was found, justifying a tailored training to learn this diagnosis.

  8. A Literature-Based Analysis of the Learning Curves of Laparoscopic Radical Prostatectomy

    Directory of Open Access Journals (Sweden)

    Daniel W. Good

    2014-05-01

    Full Text Available There is a trend for the increased adoption of minimally invasive techniques of radical prostatectomy (RP – laparoscopic (LRP and robotic assisted (RARP – from the traditional open radical retropubic prostatectomy (ORP, popularised by Partin et al. Recently there has been a dramatic expansion in the rates of RARP being performed, and there have been many early reports postulating that the learning curve for RARP is shorter than for LRP. The aim of this study was to review the literature and analyse the length of the LRP learning curves for the various outcome measures: perioperative, oncologic, and functional outcomes. A broad search of the literature was performed in November 2013 using the PubMed database. Only studies of real patients and those from 2004 until 2013 were included; those on simulators were excluded. In total, 239 studies were identified after which 13 were included. The learning curve is a heterogeneous entity, depending entirely on the criteria used to define it. There is evidence of multiple learning curves; however the length of these is dependent on the definitions used by the authors. Few studies use the more rigorous definition of plateauing of the curve. Perioperative learning curve takes approximately 150-200 cases to plateau, oncologic curve approximately 200 cases, and the functional learning curve up to 700 cases to plateau (700 for potency, 200 cases for continence. In this review, we have analysed the literature with respect to the learning curve for LRP. It is clear that the learning curve is long. This necessitates centralising LRP to high volume centres such that surgeons, trainees, and patients are able to utilise the benefits of LRP.

  9. The Learning Curve in Prostate MRI Interpretation: Self-Directed Learning Versus Continual Reader Feedback.

    Science.gov (United States)

    Rosenkrantz, Andrew B; Ayoola, Abimbola; Hoffman, David; Khasgiwala, Anunita; Prabhu, Vinay; Smereka, Paul; Somberg, Molly; Taneja, Samir S

    2017-03-01

    The purpose of this study is to evaluate the roles of self-directed learning and continual feedback in the learning curve for tumor detection by novice readers of prostate MRI. A total of 124 prostate MRI examinations classified as positive (n = 52; single Prostate Imaging Reporting and Data System [PI-RADS] category 3 or higher lesion showing Gleason score ≥ 7 tumor at MRI-targeted biopsy) or negative (n = 72; PI-RADS category 2 or lower and negative biopsy) for detectable tumor were included. These were divided into four equal-sized batches, each with matching numbers of positive and negative examinations. Six second-year radiology residents reviewed examinations to localize tumors. Three of the six readers received feedback after each examination showing the preceding case's solution. The learning curve, plotting accuracy over time, was assessed by the Akaike information criterion (AIC). Logistic regression and mixed-model ANOVA were performed. For readers with and without feedback, the learning curve exhibited an initial rapid improvement that slowed after 40 examinations (change in AIC > 0.2%). Accuracy improved from 58.1% (batch 1) to 71.0-75.3% (batches 2-4) without feedback and from 58.1% to 72.0-77.4% with feedback (p = 0.027-0.046), without a difference in the extent of improvement (p = 0.800). Specificity improved from 53.7% to 68.5-81.5% without feedback and from 55.6% to 74.1-81.5% with feedback (p = 0.006-0.010), without a difference in the extent of improvement (p = 0.891). Sensitivity improved from 59.0-61.5% (batches 1-2) to 71.8-76.9% (batches 3-4) with feedback (p = 0.052), though did not improve without feedback (p = 0.602). Sensitivity for transition zone tumors exhibited larger changes (p = 0.024) with feedback than without feedback. Sensitivity for peripheral zone tumors did not improve in either group (p > 0.3). Reader confidence increased only with feedback (p learning curve in prostate tumor detection largely reflected self

  10. Multifactorial analysis of the learning curve for totally robotic Roux-en-Y gastric bypass for morbid obesity.

    Science.gov (United States)

    Renaud, Myriam; Reibel, Nicolas; Zarnegar, Rasa; Germain, Adeline; Quilliot, Didier; Ayav, Ahmet; Bresler, Laurent; Brunaud, Laurent

    2013-11-01

    Laparoscopic Roux-en-Y gastric bypass is one of the most commonly performed bariatric operation worldwide for the surgical management of obesity. Totally robotic Roux-en-Y gastric bypass (TR-RYGBP) has been considered to be a better approach by some groups especially early in a surgeon's experience. However, the learning curve associated with TR-RYGBP has been poorly evaluated yet. The aim of this study was to evaluate the learning curve of patients who underwent TR-RYGBP. This is a prospective study of 154 first consecutive patients undergoing TR-RYGBP to analyze the influence of surgeon experience, bedside first assistant, and patient factors on operative time and postoperative complications. To give a comprehensive view of success related to the learning process, a single hybrid variable was generated. Multivariate analysis predicted the risk factors for complications and operative time. A risk-adjusted cumulative sum analysis estimated the learning curve. The learning curve for TR-RYGBP was 84 cases. Case rank and first assistant level were independent predictors of total operative time. Overall 30-day postoperative morbidity rate was 33.1 % and decreased over time. Surgeon experience (OR 2.6; CI 95 [1.290 to 5.479]; p = 0.0081) and first assistant level (OR 2.42; CI 95 [1.197 to 4.895]; p = 0.0139) remained independent predictors of composite event (operative time and complications). This study identifed criteria that should be assessed in future studies about TR-RYGBP. Both surgeon experience and bedside first assistant level affected operative duration, but surgeon experience was the most significant factor in reducing complication rates.

  11. Half-Life Learning Curves in the Defense Acquisition Life Cycle

    Science.gov (United States)

    2012-07-01

    learning include Smith (1989); Belkaoui (1976, 1986); Nanda (1979); Pegels (1976); Richardson (1978); Towill, and Kaloo (1978); Womer (1979, 1981, 1984...analysis adjusted for learning. Management Science, 24(2), 149–160. Nanda , R. (1979). Using learning curves in integration of production resources

  12. Mastering surgical skills through simulation-based learning: Practice makes one perfect

    Directory of Open Access Journals (Sweden)

    Niti Khunger

    2016-01-01

    Full Text Available Simulation-based learning in surgery is a learning model where an environment similar to real life surgical situation is created for the trainee to learn various surgical skills. It can be used to train a new operator as well to assess his skills. This methodology helps in repetitive practice of surgical skills on nonliving things so that the operator can be near-perfect when operating on a live patient. Various models are available for learning different dermatosurgery skills.

  13. Learning curves for ultrasound guided lung biopsy in the hands of respiratory physicians

    DEFF Research Database (Denmark)

    Laursen, Christian; Naur, Therese Maria Henriette; Bodtger, Uffe

    2016-01-01

    Background: The aim of this study was to determine learning curves for ultrasound guided transthoracic needle biopsies (US-TTNB) performed by respiratory physicians after implementation at three different centers.Methods: During January 2012 to August 2014 patients were included if they had...... are depicted in figure 1. Six of the physicians had learning curves with a relatively downward or stable projection as a sign of developing competence. Three physicians, however, had learning curves with an upward projection indicating unacceptable competence in performing the procedure...

  14. Análise de 33 peças cirúrgicas de colectomias laparoscópicas para câncer, durante a curva de aprendizado inicial: margens oncológicas e número de linfonodos não diferem de colectomias abertas Analysis of 33 surgical specimens of laparoscopic resections for colorectal cancer in the early learning curve: margins and nodes harvest do not differ from open resections

    Directory of Open Access Journals (Sweden)

    Augusto Motta Neiva

    2010-03-01

    no início da experiência com colectomia laparoscópica, os critérios para ressecção oncológica podem ser preservados quando os procedimentos são realizados por cirurgiões especialistas trabalhando com equipe especializada em patologia gastrointestinal.INTRODUCTION: Colorectal laparoscopic surgery is considered a procedure with long learning curve. Despite surgeons with experience in laparoscopic surgery are able to achieve the same oncological results obtained in open procedures, it is important to evaluate if these good results are sustained during the learning curve. The aim of this study was to evaluate the adequacy of the margins and the lymph nodes harvest in early learning curve of laparoscopic colectomies performed by specialized surgeons compared to open colectomies. METHODS: Thirty-three surgical specimens of laparoscopic resections for colorectal cancer performed during the early learning curve were evaluated. The following data were analyzed: age, sex, tumor location, pathologic classification, lymph node harvest and proximal and distal margins. Data were compared to a control group of 45 open resections for colorectal cancer. RESULTS: Age, tumor location and Dukes classification of laparoscopic and open groups were similar. Laparoscopic group had more female patients. Distal margins were similar between the groups [mean of 7,15 cm (SD ± 9,98 for open and 8,26 cm (SD ± 11,5 for laparoscopic group, p=NS]. There was no difference in the lymph nodes harvest between the groups. The mean of lymph nodes harvest of open and laparoscopic groups were 19 (SD ± 19,41 and 21 (SD ± 14,73, respectively, (p=NS. CONCLUSION: Oncologic margins and lymph nodes harvest obtained during early learning curve of laparoscopic resections were similar to open procedures. Despite the natural difficulties faced during early learning curve, oncologic criteria can be achieved when laparoscopic colorectal resections are performed by specialized surgeons working with

  15. Mastering Robotic Surgery: Where Does the Learning Curve Lead Us?

    Science.gov (United States)

    Andolfi, Ciro; Umanskiy, Konstantin

    2017-01-18

    The robotic surgical technology introduced over the last decade and a half has revolutionized many aspects of performing complex procedures. It combines technological and clinical innovations to improve surgical quality and patient outcomes. Yet, to date, there is still a lack of standardization in training and certification of robotic surgeons. The criteria for proficiency and credentialing in robotic surgery vary widely among institutions. The aim of this review is to discuss the key points of training and surgeon assessment in robotic surgery, as well as the challenges that still need to be overcome.

  16. Learning Curve of the Application of Huang Three-Step Maneuver in a Laparoscopic Spleen-Preserving Splenic Hilar Lymphadenectomy for Advanced Gastric Cancer.

    Science.gov (United States)

    Huang, Ze-Ning; Huang, Chang-Ming; Zheng, Chao-Hui; Li, Ping; Xie, Jian-Wei; Wang, Jia-Bin; Lin, Jian-Xian; Lu, Jun; Chen, Qi-Yue; Cao, Long-Long; Lin, Mi; Tu, Ru-Hong

    2016-03-01

    To investigate the learning curve of the application of Huang 3-step maneuver, which was summarized and proposed by our center for the treatment of advanced upper gastric cancer. From April 2012 to March 2013, 130 consecutive patients who underwent a laparoscopic spleen-preserving splenic hilar lymphadenectomy (LSPL) by a single surgeon who performed Huang 3-step maneuver were retrospectively analyzed. The learning curve was analyzed based on the moving average (MA) method and the cumulative sum method (CUSUM). Surgical outcomes, short-term outcomes, and follow-up results before and after learning curve were contrastively analyzed. A stepwise multivariate logistic regression was used for a multivariable analysis to determine the factors that affect the operative time using Huang 3-step maneuver. Based on the CUSUM, the learning curve for Huang 3-step maneuver was divided into phase 1 (cases 1-40) and phase 2 (cases 41-130). The dissection time (DT) (P < 0.001), blood loss (BL) (P < 0.001), and number of vessels injured in phase 2 were significantly less than those in phase 1. There were no significant differences in the clinicopathological characteristics, short-term outcomes, or major postoperative complications between the learning curve phases. Univariate and multivariate analyses revealed that body mass index (BMI), short gastric vessels (SGVs), splenic hilar artery (SpA) type, and learning curve phase were significantly associated with DT. In the entire group, 124 patients were followed for a median time of 23.0 months (range, 3-30 months). There was no significant difference in the survival curve between phases. AUGC patients with a BMI less than 25 kg/m², a small number of SGVs, and a concentrated type of SpA are ideal candidates for surgeons who are in phase 1 of the learning curve.

  17. Unraveling the photovoltaic technology learning curve by incorporation of input price changes and scale effects

    Energy Technology Data Exchange (ETDEWEB)

    Yu, C.F.; van Sark, W.G.J.H.M.; Alsema, E.A. [Department of Science, Technology and Society, Copernicus Institute for Sustainable Development and Innovation, Utrecht University, Heidelberglaan 2, 3584 CS Utrecht (Netherlands)

    2011-01-15

    In a large number of energy models, the use of learning curves for estimating technological improvements has become popular. This is based on the assumption that technological development can be monitored by following cost development as a function of market size. However, recent data show that in some stages of photovoltaic technology (PV) production, the market price of PV modules stabilizes even though the cumulative capacity increases. This implies that no technological improvement takes place in these periods: the cost predicted by the learning curve in the PV study is lower than the market one. We propose that this bias results from ignoring the effects of input prices and scale effects, and that incorporating the input prices and scale effects into the learning curve theory is an important issue in making cost predictions more reliable. In this paper, a methodology is described to incorporate the scale and input-prices effect as the additional variables into the one factor learning curve, which leads to the definition of the multi-factor learning curve. This multi-factor learning curve is not only derived from economic theories, but also supported by an empirical study. The results clearly show that input prices and scale effects are to be included, and that, although market prices are stabilizing, learning is still taking place. (author)

  18. Learning curve for laparoendoscopic single-site surgery for an experienced laparoscopic surgeon

    Directory of Open Access Journals (Sweden)

    Pao-Ling Torng

    2013-11-01

    Conclusion: LESS is a safe and feasible alternative to conventional laparoscopic surgery for adnexal and uterine diseases. A learning curve is not required for LESS surgery for experienced laparoscopic surgeons.

  19. Effective e-learning in surgical education: the core values underpinning effective e-learning environments and how these may be enhanced for future surgical education.

    Science.gov (United States)

    Bamford, R; Coulston, J

    2016-01-01

    e-learning is a valuable tool that has a number of advantages for Surgical Oncology training and education. The rapidly evolving nature of, and limited clinical exposure to oncological practice creates challenges for surgical trainees to stay up to date and engaged. Online learning can be accessed anywhere at any time and allows trainees to develop, apply and be assessed on their learning. To be effective, it must be educationally sound and embrace technology to enhance learners' experience.

  20. Early results of the Bernese periacetabular osteotomy: the learning curve at an academic medical center.

    Science.gov (United States)

    Peters, Christopher L; Erickson, Jill A; Hines, Jerod L

    2006-09-01

    Most reports on the results of the Bernese periacetabular osteotomy for the treatment of developmental dysplasia of the hip have been by the originators of the procedure. In 1997, we began to use this osteotomy without direct training from the originators of the procedure. Seventy-three patients (eighty-three hips) underwent a Bernese periacetabular osteotomy between 1997 and 2003 and were followed prospectively with use of the Harris hip score to assess clinical results and with use of anteroposterior pelvic and false-profile lateral plain radiographs to assess radiographic results. The three-dimensional position of the acetabulum was recorded preoperatively and postoperatively. The mean duration of follow-up was forty-six months. The average Harris hip score improved from 54 to 87 points (p Bernese periacetabular osteotomy have been encouraging, with a 92% survival rate at thirty-six months. The occurrence of complications demonstrates a substantial learning curve. Recognition of the true preoperative acetabular version and reorientation of the acetabulum into an appropriately anteverted position have become important factors in surgical decision-making. Therapeutic Level IV.

  1. A primer on the statistical modelling of learning curves in health professions education.

    Science.gov (United States)

    Pusic, Martin V; Boutis, Kathy; Pecaric, Martin R; Savenkov, Oleksander; Beckstead, Jason W; Jaber, Mohamad Y

    2017-08-01

    Learning curves are a useful way of representing the rate of learning over time. Features include an index of baseline performance (y-intercept), the efficiency of learning over time (slope parameter) and the maximal theoretical performance achievable (upper asymptote). Each of these parameters can be statistically modelled on an individual and group basis with the resulting estimates being useful to both learners and educators for feedback and educational quality improvement. In this primer, we review various descriptive and modelling techniques appropriate to learning curves including smoothing, regression modelling and application of the Thurstone model. Using an example dataset we demonstrate each technique as it specifically applies to learning curves and point out limitations.

  2. What Is the Expected Learning Curve in Computer-assisted Navigation for Bone Tumor Resection?

    Science.gov (United States)

    Farfalli, Germán L; Albergo, José I; Ritacco, Lucas E; Ayerza, Miguel A; Milano, Federico E; Aponte-Tinao, Luis A

    2017-03-01

    Computer navigation during surgery can help oncologic surgeons perform more accurate resections. However, some navigation studies suggest that this tool may result in unique intraoperative problems and increased surgical time. The degree to which these problems might diminish with experience-the learning curve-has not, to our knowledge, been evaluated for navigation-assisted tumor resections. (1) What intraoperative technical problems were observed during the first 2 years using navigation? (2) What was the mean time for navigation procedures and the time improvement during the learning curve? (3) Have there been any differences in the accuracy of the registration technique that occurred over time? (4) Did navigation achieve the goal of achieving a wide bone margin? All patients who underwent preoperative virtual planning for tumor bone resections and operated on with navigation assistance from 2010 to 2012 were prospectively collected. Two surgeons (GLF, LAA-T) performed the intraoperative navigation assistance. Both surgeons had more than 5 years of experience in orthopaedic oncology with more than 60 oncology cases per year per surgeon. This study includes from the very first patients performed with navigation. Although they did not take any formal training in orthopaedic oncology navigation, both surgeons were trained in navigation for knee prostheses. Between 2010 and 2012, we performed 124 bone tumor resections; of these, 78 (63%) cases were resected using intraoperative navigation assistance. During this period, our general indications for use of navigation included pelvic and sacral tumors and those tumors that were reconstructed with massive bone allografts to obtain precise matching of the host and allograft osteotomies. Seventy-eight patients treated with this technology were included in the study. Technical problems (crashes) and time for the navigation procedure were reported after surgery. Accuracy of the registration technique was defined and the

  3. Learning Curves and Bootstrap Estimates for Inference with Gaussian Processes: A Statistical Mechanics Study

    DEFF Research Database (Denmark)

    Malzahn, Dorthe; Opper, Manfred

    2003-01-01

    We employ the replica method of statistical physics to study the average case performance of learning systems. The new feature of our theory is that general distributions of data can be treated, which enables applications to real data. For a class of Bayesian prediction models which are based on ...... on Gaussian processes, we discuss Bootstrap estimates for learning curves....

  4. Laparoscopy Instructional Videos : The Effect of Preoperative Compared With Intraoperative Use on Learning Curves

    NARCIS (Netherlands)

    Broekema, Theo H.; Talsma, Aaldert K.; Wevers, Kevin P.; Pierie, Jean-Pierre E. N.

    OBJECTIVE: Previous studies have shown that the use of intraoperative instructional videos has a positive effect on learning laparoscopic procedures. This study investigated the effect of the timing of the instructional videos on learning curves in laparoscopic skills training. DESIGN: After

  5. Endoscopic Versus Microscopic Approach in Stapes Surgery: Are Operative Times and Learning Curve Important for Making the Choice?

    Science.gov (United States)

    Iannella, Giannicola; Magliulo, Giuseppe

    2016-10-01

    Analyze the surgical outcomes of endoscopic stapes surgery, comparing the results with a conventional stapes surgery under microscopic approach. Estimate the operation type of each surgical approach and show a learning curve of endoscopic stapes surgery. Retrospective study. Tertiary referral center. Twenty patients who underwent endoscopic stapedotomy for otosclerosis and 20 patients who underwent microscopic stapedotomy for otosclerosis. Endoscopic and microscopic stapes surgery. Operating time, preoperative and postoperative hearing, intraoperative findings, postoperative complications, and postoperative pain. The group of patients who underwent endoscopic stapes surgery showed a mean operative time calculated to be 45.0 min. The group of patients treated by microscopic approach had an estimated mean value of 36.5 min. Statistical difference was evident (p value = 0.01). The average duration of endoscopic surgery varied as the surgeon gained experience. There were no statistical differences between the average surgical times for the endoscopic and microscopic approaches (p >0.05) in the last 4-month period of surgery. Through the endoscopic approach the percentage of ears with a postoperative air-bone gap ≤20 dB was 95%. No difference from the percentage of the microscopic group (90%) (p >0.05) was reported. No difference regarding the incidence of intraoperative findings and postoperative complications between endoscopic and microscopic approaches was found. Audiological outcomes achieved by endoscopic surgery are similar to the results obtained through a microscopic approach. Longer initial operative times and a learning curve are the principal grounds that might discourage most ear-surgeons from commencing endoscopic stapes surgery.

  6. Improving Accuracy and Temporal Resolution of Learning Curve Estimation for within- and across-Session Analysis.

    Directory of Open Access Journals (Sweden)

    Matthias Deliano

    Full Text Available Estimation of learning curves is ubiquitously based on proportions of correct responses within moving trial windows. Thereby, it is tacitly assumed that learning performance is constant within the moving windows, which, however, is often not the case. In the present study we demonstrate that violations of this assumption lead to systematic errors in the analysis of learning curves, and we explored the dependency of these errors on window size, different statistical models, and learning phase. To reduce these errors in the analysis of single-subject data as well as on the population level, we propose adequate statistical methods for the estimation of learning curves and the construction of confidence intervals, trial by trial. Applied to data from an avoidance learning experiment with rodents, these methods revealed performance changes occurring at multiple time scales within and across training sessions which were otherwise obscured in the conventional analysis. Our work shows that the proper assessment of the behavioral dynamics of learning at high temporal resolution can shed new light on specific learning processes, and, thus, allows to refine existing learning concepts. It further disambiguates the interpretation of neurophysiological signal changes recorded during training in relation to learning.

  7. Hysteroscopic sterilization using a virtual reality simulator: assessment of learning curve.

    Science.gov (United States)

    Janse, Juliënne A; Goedegebuure, Ruben S A; Veersema, Sebastiaan; Broekmans, Frank J M; Schreuder, Henk W R

    2013-01-01

    To assess the learning curve using a virtual reality simulator for hysteroscopic sterilization with the Essure method. Prospective multicenter study (Canadian Task Force classification II-2). University and teaching hospital in the Netherlands. Thirty novices (medical students) and five experts (gynecologists who had performed >150 Essure sterilization procedures). All participants performed nine repetitions of bilateral Essure placement on the simulator. Novices returned after 2 weeks and performed a second series of five repetitions to assess retention of skills. Structured observations on performance using the Global Rating Scale and parameters derived from the simulator provided measurements for analysis. The learning curve is represented by improvement per procedure. Two-way repeated-measures analysis of variance was used to analyze learning curves. Effect size (ES) was calculated to express the practical significance of the results (ES ≥ 0.50 indicates a large learning effect). For all parameters, significant improvements were found in novice performance within nine repetitions. Large learning effects were established for six of eight parameters (p < .001; ES, 0.50-0.96). Novices approached expert level within 9 to 14 repetitions. The learning curve established in this study endorses future implementation of the simulator in curricula on hysteroscopic skill acquisition for clinicians who are interested in learning this sterilization technique. Copyright © 2013 AAGL. Published by Elsevier Inc. All rights reserved.

  8. The Initial Learning Curve for Robot-Assisted Sleeve Gastrectomy: A Surgeon's Experience While Introducing the Robotic Technology in a Bariatric Surgery Department.

    Science.gov (United States)

    Vilallonga, Ramon; Fort, José Manuel; Gonzalez, Oscar; Caubet, Enric; Boleko, Angeles; Neff, Karl John; Armengol, Manel

    2012-01-01

    Objective. Robot-assisted sleeve gastrectomy has the potential to treat patients with obesity and its comorbidities. To evaluate the learning curve for this procedure before undergoing Roux en-Y gastric bypass is the objective of this paper. Materials and Methods. Robot-assisted sleeve gastrectomy was attempted in 32 consecutive patients. A survey was performed in order to identify performance variables during completion of the learning curve. Total operative time (OT), docking time (DT), complications, and length of hospital stay were compared among patients divided into two cohorts according to the surgical experience. Scattergrams and continuous curves were plotted to develop a robotic sleeve gastrectomy learning curve. Results. Overall OT time decreased from 89.8 minutes in cohort 1 to 70.1 minutes in cohort 2, with less than 5% change in OT after case 19. Time from incision to docking decreased from 9.5 minutes in cohort 1 to 7.6 minutes in cohort 2. The time required to dock the robotic system also decreased. The complication rate was the same in the two cohorts. Conclusion. Our survey indicates that technique and outcomes for robot-assisted sleeve gastrectomy gradually improve with experience. We found that the learning curve for performing a sleeve gastrectomy using the da Vinci system is completed after about 20 cases.

  9. Testing Theories of Transfer Using Error Rate Learning Curves.

    Science.gov (United States)

    Koedinger, Kenneth R; Yudelson, Michael V; Pavlik, Philip I

    2016-07-01

    We analyze naturally occurring datasets from student use of educational technologies to explore a long-standing question of the scope of transfer of learning. We contrast a faculty theory of broad transfer with a component theory of more constrained transfer. To test these theories, we develop statistical models of them. These models use latent variables to represent mental functions that are changed while learning to cause a reduction in error rates for new tasks. Strong versions of these models provide a common explanation for the variance in task difficulty and transfer. Weak versions decouple difficulty and transfer explanations by describing task difficulty with parameters for each unique task. We evaluate these models in terms of both their prediction accuracy on held-out data and their power in explaining task difficulty and learning transfer. In comparisons across eight datasets, we find that the component models provide both better predictions and better explanations than the faculty models. Weak model variations tend to improve generalization across students, but hurt generalization across items and make a sacrifice to explanatory power. More generally, the approach could be used to identify malleable components of cognitive functions, such as spatial reasoning or executive functions. Copyright © 2016 Cognitive Science Society, Inc.

  10. Surgical Practical Skills Learning Curriculum: Implementation and Interns' Confidence Perceptions.

    Science.gov (United States)

    Acosta, Danilo; Castillo-Angeles, Manuel; Garces-Descovich, Alejandro; Watkins, Ammara A; Gupta, Alok; Critchlow, Jonathan F; Kent, Tara S

    2017-08-18

    To provide an overview of the practical skills learning curriculum and assess its effects over time on the surgical interns' perceptions of their technical skills, patient management, administrative tasks, and knowledge. An 84-hour practical skills curriculum composed of didactic, simulation, and practical sessions was implemented during the 2015 to 2016 academic year for general surgery interns. Totally, 40% of the sessions were held during orientation, whereas the remainder sessions were held throughout the academic year. Interns' perceptions of their technical skills, administrative tasks, patient management, and knowledge were assessed by the practical skills curriculum residents' perception survey at various time points during their intern year (baseline, midpoint, and final). Interns were also asked to fill out an evaluation survey at the completion of each session to obtain feedback on the curriculum. General Surgery Residency program at a tertiary care academic institution. 20 General Surgery categorical and preliminary interns. Significant differences were found over time in interns' perceptions on their technical skills, patient management, administrative tasks, and knowledge (p skills, patient management, administrative tasks, and knowledge (p > 0.05 for all). Implementation of a Practical Skills Curriculum in surgical internships can improve interns' confidence perception on their technical skills, patient management skills, administrative tasks, and knowledge. Copyright © 2017. Published by Elsevier Inc.

  11. Learning Curve Analysis of Different Stages of Robotic-Assisted Laparoscopic Hysterectomy

    Science.gov (United States)

    Tang, Feng-Hsiang

    2017-01-01

    Objective. To analyze the learning curves of the different stages of robotic-assisted laparoscopic hysterectomy. Design. Retrospective analysis. Design Classification. Canadian Task Force classification II-2. Setting. Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. Patient Intervention. Women receiving robotic-assisted total and subtotal laparoscopic hysterectomies for benign conditions from May 1, 2013, to August 31, 2015. Measurements and Main Results. The mean age, body mass index (BMI), and uterine weight were 46.44 ± 5.31 years, 23.97 ± 4.75 kg/m2, and 435.48 ± 250.62 g, respectively. The most rapid learning curve was obtained for the main surgery console stage; eight experiences were required to achieve duration stability, and the time spent in this stage did not violate the control rules. The docking stage required 14 experiences to achieve duration stability, and the suture stage was the most difficult to master, requiring 26 experiences. BMI did not considerably affect the duration of the three stages. The uterine weight and the presence of adhesion did not substantially affect the main surgery console time. Conclusion. Different stages of robotic-assisted laparoscopic hysterectomy have different learning curves. The main surgery console stage has the most rapid learning curve, whereas the suture stage has the slowest learning curve. PMID:28373977

  12. Simultaneous development of laparoscopy and robotics provides acceptable perioperative outcomes and shows robotics to have a faster learning curve and to be overall faster in rectal cancer surgery: analysis of novice MIS surgeon learning curves.

    Science.gov (United States)

    Melich, George; Hong, Young Ki; Kim, Jieun; Hur, Hyuk; Baik, Seung Hyuk; Kim, Nam Kyu; Sender Liberman, A; Min, Byung Soh

    2015-03-01

    Laparoscopy offers some evidence of benefit compared to open rectal surgery. Robotic rectal surgery is evolving into an accepted approach. The objective was to analyze and compare laparoscopic and robotic rectal surgery learning curves with respect to operative times and perioperative outcomes for a novice minimally invasive colorectal surgeon. One hundred and six laparoscopic and 92 robotic LAR rectal surgery cases were analyzed. All surgeries were performed by a surgeon who was primarily trained in open rectal surgery. Patient characteristics and perioperative outcomes were analyzed. Operative time and CUSUM plots were used for evaluating the learning curve for laparoscopic versus robotic LAR. Laparoscopic versus robotic LAR outcomes feature initial group operative times of 308 (291-325) min versus 397 (373-420) min and last group times of 220 (212-229) min versus 204 (196-211) min-reversed in favor of robotics; major complications of 4.7 versus 6.5 % (NS), resection margin involvement of 2.8 versus 4.4 % (NS), conversion rate of 3.8 versus 1.1 (NS), lymph node harvest of 16.3 versus 17.2 (NS), and estimated blood loss of 231 versus 201 cc (NS). Due to faster learning curves for extracorporeal phase and total mesorectal excision phase, the robotic surgery was observed to be faster than laparoscopic surgery after the initial 41 cases. CUSUM plots demonstrate acceptable perioperative surgical outcomes from the beginning of the study. Initial robotic operative times improved with practice rapidly and eventually became faster than those for laparoscopy. Developing both laparoscopic and robotic skills simultaneously can provide acceptable perioperative outcomes in rectal surgery. It might be suggested that in the current milieu of clashing interests between evolving technology and economic constrains, there might be advantages in embracing both approaches.

  13. Single-centre experience of retroperitoneoscopic approach in urology with tips to overcome the steep learning curve

    Directory of Open Access Journals (Sweden)

    Aneesh Srivastava

    2016-01-01

    Full Text Available Context: The retroperitoneoscopic or retroperitoneal (RP surgical approach has not become as popular as the transperitoneal (TP one due to the steeper learning curve. Aims: Our single-institution experience focuses on the feasibility, advantages and complications of retroperitoneoscopic surgeries (RS performed over the past 10 years. Tips and tricks have been discussed to overcome the steep learning curve and these are emphasised. Settings and Design: This study made a retrospective analysis of computerised hospital data of patients who underwent RP urological procedures from 2003 to 2013 at a tertiary care centre. Patients and Methods: Between 2003 and 2013, 314 cases of RS were performed for various urological procedures. We analysed the operative time, peri-operative complications, time to return of bowel sound, length of hospital stay, and advantages and difficulties involved. Post-operative complications were stratified into five grades using modified Clavien classification (MCC. Results: RS were successfully completed in 95.5% of patients, with 4% of the procedures electively performed by the combined approach (both RP and TP; 3.2% required open conversion and 1.3% were converted to the TP approach. The most common cause for conversion was bleeding. Mean hospital stay was 3.2 ± 1.2 days and the mean time for returning of bowel sounds was 16.5 ± 5.4 h. Of the patients, 1.4% required peri-operative blood transfusion. A total of 16 patients (5% had post-operative complications and the majority were grades I and II as per MCC. The rates of intra-operative and post-operative complications depended on the difficulty of the procedure, but the complications diminished over the years with the increasing experience of surgeons. Conclusion: Retroperitoneoscopy has proven an excellent approach, with certain advantages. The tips and tricks that have been provided and emphasised should definitely help to minimise the steep learning curve.

  14. Simple Models Create Steep Learning Curves in Academic Design Studio

    DEFF Research Database (Denmark)

    Hansen, Peter Lundsgaard; Dam, Torben; Le Goffic, Virginie Corinne

    2014-01-01

    This paper presents an easily adaptable, very learning-efficient and solution-oriented design studio method: ‘the simple model method’. On a practical level it solves well known problems that occur when teaching design studios. On a theoretical level it suggests a ‘third way’ of bridging design......, their supervisors and other actors. The simple model is a non-verbal agent. However, due to its simplicity it enables verbalization supporting a solution-focused design studio teaching strategy. The simple model method is presented through a specific design studio course undertaken at the University of Copenhagen...... theory positions normally regarded as mutually incompatible. The method is the result of years of ‘trial and error’ design studio teaching at the University of Copenhagen, triangulated with academic design theory research. Research based design studio teaching poses a fundamental pedagogical challenge...

  15. Surgical education and adult learning: Integrating theory into practice [version 1; referees: 3 approved

    Directory of Open Access Journals (Sweden)

    Prem Rashid

    2017-02-01

    Full Text Available Surgical education continues to evolve from the master-apprentice model. Newer methods of the process need to be used to manage the dual challenges of educating while providing safe surgical care. This requires integrating adult learning concepts into delivery of practical training and education in busy clinical environments. A narrative review aimed at outlining and integrating adult learning and surgical education theory was undertaken. Additionally, this information was used to relate the practical delivery of surgical training and education in day-to-day surgical practice. Concepts were sourced from reference material. Additional material was found using a PubMed search of the words: ‘surgical education theory’ and ‘adult learning theory medical’. This yielded 1351 abstracts, of which 43 articles with a focus on key concepts in adult education theory were used. Key papers were used to formulate structure and additional cross-referenced papers were included where appropriate. Current concepts within adult learning have a lot to offer when considering how to better deliver surgical education and training. Better integration of adult learning theory can be fruitful. Individual teaching surgical units need to rethink their paradigms and consider how each individual can contribute to the education experience. Up skilling courses for trainers can do much to improve the delivery of surgical education. Understanding adult learning concepts and integrating these into day-to-day teaching can be valuable.

  16. Evaluation of the learning curve of non-penetrating glaucoma surgery.

    Science.gov (United States)

    Aslan, Fatih; Yuce, Berna; Oztas, Zafer; Ates, Halil

    2017-08-11

    To evaluate the learning curve of non-penetrating glaucoma surgery (NPGS). The study included 32 eyes of 27 patients' (20 male and 7 female) with medically uncontrolled glaucoma. Non-penetrating glaucoma surgeries performed by trainees under control of an experienced surgeon between 2005 and 2007 at our tertiary referral hospital were evaluated. Residents were separated into two groups. Humanistic training model applied to the one in the first group, he studied with experimental models before performing NPGS. Two residents in the second group performed NPGS after a conventional training model. Surgeries of the residents were recorded on video and intraoperative parameters were scored by the experienced surgeon at the end of the study. Postoperative intraocular pressure, absolute and total success rates were analyzed. In the first group 19 eyes of 16 patients and in the second group 13 eyes of 11 patients had been operated by residents. Intraoperative parameters and complication rates were not statistically significant between groups (p > 0.05, Chi-square). The duration of surgery was 32.7 ± 5.6 min in the first group and 45 ± 3.8 min in the second group. The difference was statistically significant (p < 0.001, Student's t test). Absolute and total success was 68.8 and 93.8% in the first group and 62.5 and 87.5% in the second group, respectively. The difference was not statistically significant. Humanistic and conventional training models under control of an experienced surgeon are safe and effective for senior residents who manage phacoemulsification surgery in routine cataract cases. Senior residents can practice these surgical techniques with reasonable complication rates.

  17. SILC for SILC: Single Institution Learning Curve for Single-Incision Laparoscopic Cholecystectomy

    Directory of Open Access Journals (Sweden)

    Chee Wei Tay

    2013-01-01

    Full Text Available Objectives. We report the single-incision laparoscopic cholecystectomy (SILC learning experience of 2 hepatobiliary surgeons and the factors that could influence the learning curve of SILC. Methods. Patients who underwent SILC by Surgeons A and B were studied retrospectively. Operating time, conversion rate, reason for conversion, identity of first assistants, and their experience with previous laparoscopic cholecystectomy (LC were analysed. CUSUM analysis is used to identify learning curve. Results. Hundred and nineteen SILC cases were performed by Surgeons A and B, respectively. Eight cases required additional port. In CUSUM analysis, most conversion occurred during the first 19 cases. Operating time was significantly lower (62.5 versus 90.6 min, P = 0.04 after the learning curve has been overcome. Operating time decreases as the experience increases, especially Surgeon B. Most conversions are due to adhesion at Calot’s triangle. Acute cholecystitis, patients’ BMI, and previous surgery do not seem to influence conversion rate. Mean operating times of cases assisted by first assistant with and without LC experience were 48 and 74 minutes, respectively (P = 0.004. Conclusion. Nineteen cases are needed to overcome the learning curve of SILC. Team work, assistant with CLC experience, and appropriate equipment and technique are the important factors in performing SILC.

  18. Is the Learning Curve of Robotic Low Anterior Resection Shorter Than Laparoscopic Low Anterior Resection for Rectal Cancer?

    OpenAIRE

    Park, Eun Jung; Kim, Chang Woo; Cho, Min Soo; Kim, Dong Wook; MIN, BYUNG SOH; Baik, Seung Hyuk; Lee, Kang Young; Kim, Nam Kyu

    2014-01-01

    Abstract As robotic surgery was developed with ergonomic designs, there are expectations that the technical advantages of robotic surgery can shorten the learning curve. However, there is no comparative study, so far, to evaluate the learning curve between robotic and laparoscopic rectal cancer surgeries. Therefore, the aim of this study is to compare the learning curve of robotic low anterior resection (LAR) with laparoscopic LAR for rectal cancer. Patients who underwent robotic or laparosco...

  19. Comparison of Surgical Parameters and Results between Curved Varus Osteotomy and Rotational Osteotomy for Osteonecrosis of the Femoral Head.

    Science.gov (United States)

    Lee, Young-Kyun; Park, Chan Ho; Ha, Yong-Chan; Kim, Do-Yeon; Lyu, Sung-Hwa; Koo, Kyung-Hoi

    2017-06-01

    Various osteotomies have been introduced to treat osteonecrosis of the femoral head. The purpose of this study was to compare surgical parameters, postoperative limb length discrepancy, and minimum 5-year clinical and radiological results between transtrochanteric curved varus osteotomy (TCVO) and transtrochanteric rotational osteotomy (TRO) for osteonecrosis of the femoral head. From 2004 to 2009, 103 consecutive TROs (97 patients) followed by 72 consecutive TCVOs (64 patients) were performed for the treatment of osteonecrosis of the femoral head. Of these, 85 patients (91 hips) in the TRO group and 58 patients (65 hips) in the TCVO group completed minimum 5-year clinical and radiological follow-up. The Kaplan-Meier product-limit method was used to estimate survival. The TCVO group had shorter operation time (p TRO group and 7 hips (10.8%) in the TCVO group (p = 0.007). Osteophyte formation was observed in 34 hips (37.4%) in the TRO group and 13 hips (20%) in the TCVO group (p = 0.020). Fifteen hips (16.5%) in the TRO group and 7 hips (10.8%) in the TCVO group underwent conversion total hip arthroplasty (THA). The survival rate at 9 years with radiographic collapse as the endpoint was 68.7% (95% confidence interval [CI], 58.1% to 79.3%) in the TRO group, and 84.7% (95% CI, 71.5% to 97.9%) in the TCVO group. With conversion to THA as the endpoint, the survival rate was 82.2% (95% CI, 73.1% to 91.3%) in the TRO group and 89.2% (95% CI, 81.7% to 96.7%) in the TCVO group. The comparison indicates that TCVO was better than TRO in terms of surgical parameters including operation time and estimated blood loss while the 9-year survival rates were similar.

  20. An exploratory analysis of personality, attitudes, and study skills on the learning curve within a team-based learning environment.

    Science.gov (United States)

    Persky, Adam M; Henry, Teague; Campbell, Ashley

    2015-03-25

    To examine factors that determine the interindividual variability of learning within a team-based learning environment. Students in a pharmacokinetics course were given 4 interim, low-stakes cumulative assessments throughout the semester and a cumulative final examination. Students' Myers-Briggs personality type was assessed, as well as their study skills, motivations, and attitudes towards team-learning. A latent curve model (LCM) was applied and various covariates were assessed to improve the regression model. A quadratic LCM was applied for the first 4 assessments to predict final examination performance. None of the covariates examined significantly impacted the regression model fit except metacognitive self-regulation, which explained some of the variability in the rate of learning. There were some correlations between personality type and attitudes towards team learning, with introverts having a lower opinion of team-learning than extroverts. The LCM could readily describe the learning curve. Extroverted and introverted personality types had the same learning performance even though preference for team-learning was lower in introverts. Other personality traits, study skills, or practice did not significantly contribute to the learning variability in this course.

  1. Radiologic findings and curve progression 22 years after treatment for adolescent idiopathic scoliosis: comparison of brace and surgical treatment with matching control group of straight individuals.

    Science.gov (United States)

    Danielsson, A J; Nachemson, A L

    2001-03-01

    This study is a follow-up investigation for a consecutive series of patients with adolescent idiopathic scoliosis treated between 1968 and 1977. In this series, 156 patients underwent surgery with distraction and fusion using Harrington rods, and 127 were treated with brace. To determine the long-term outcome in terms of radiologic findings and curve progression at least 20 years after completion of the treatment. Radiologic appearance is important in comparing the outcome of different treatment options and in evaluating clinical results. Earlier studies have shown a slight increase of the Cobb angle in brace-treated patients with time, but not in fused patients. Of 283 patients, 252 attended a clinical and radiologic follow-up assessment by an unbiased observer (91% of the surgically treated and 87% of the brace-treated patients). This evaluation included chart reviews, validated questionnaires, clinical examination, and full-length standing frontal and lateral roentgenographs. Curve size was measured by the Cobb method on anteroposterior roentgenograms as well as by sagittal contour and balance on lateral films. The occurrence of any degenerative changes or other complications was noted. An age- and gender-matched control group of 100 individuals was randomly selected and subjected to the same examinations. The mean follow-up times were 23 years for surgically treated group and 22 years for brace-treated group. The deterioration of the curves was 3.5 degrees for all the surgically treated curves and 7.9 degrees for all the brace-treated curves (P flat back syndrome developed in four patients. Eight of the patients treated with fusion (5.1%) had undergone some additional curve-related surgical procedure. The lumbar lordosis was less in the surgically treated than in the brace-treated patients or the control group (mean, 33 degrees vs 45 degrees and 44 degrees, respectively). Both surgically treated and brace-treated patients had more degenerative disc changes than

  2. Laparoscopic suturing learning curve in an open versus closed box trainer

    NARCIS (Netherlands)

    Rodrigues, S.P.; Horeman, T.; Blomjous, M.S.H.; Hiemstra, E.; Van den Dobbelsteen, J.J.; Jansen, F.W.

    2015-01-01

    Background The aim of this study was to examine the influence of training under direct vision prior to training with indirect vision on the learning curve of the laparoscopic suture task. Methods Novices were randomized in two groups. Group 1 performed three suturing tasks in a transparent laparosc

  3. Unraveling the photovoltaic technology learning curve by incorporation of input price changes and scale effects

    NARCIS (Netherlands)

    Yu, C.F.; van Sark, W.G.J.H.M.|info:eu-repo/dai/nl/074628526; Alsema, E.A.|info:eu-repo/dai/nl/073416258

    2011-01-01

    In a large number of energy models, the use of learning curves for estimating technological improvements has become popular. This is based on the assumption that technological development can be monitored by following cost development as a function of market size. However, recent data show that in

  4. Unraveling the photovoltaic technology learning curve by incorporation of input price changes and scale effects

    NARCIS (Netherlands)

    Yu, C.F.; van Sark, W.G.J.H.M.; Alsema, E.A.

    2011-01-01

    In a large number of energy models, the use of learning curves for estimating technological improvements has become popular. This is based on the assumption that technological development can be monitored by following cost development as a function of market size. However, recent data show that in s

  5. Endoscopically assisted reduction and fixation of condylar neck/base fractures--The learning curve.

    Science.gov (United States)

    Loukota, R A

    2006-12-01

    Following the introduction of a new technique for fixation of fractures of the condylar neck and base in our department, the operative times were compared with those for the traditional and frequently used method of open reduction and internal fixation. A distinct learning curve was seen.

  6. Learning curves for ultrasound guided lung biopsy in the hands of respiratory physicians

    DEFF Research Database (Denmark)

    Laursen, Christian; Naur, Therese Maria Henriette; Bodtger, Uffe

    2016-01-01

    a registered US-TTNB procedure at any of the three centers. The US-TTNB was defined as being successful if the result was diagnostic and otherwise as being unsuccessful. Histology or cytology results and clinical follow-up were used as a reference tests. The learning curves for physicians having performed...

  7. Starspot signature on the light curve: Learning about the latitudinal distribution of spots

    CERN Document Server

    Santos, A R G; Avelino, P P; García, R A; Mathur, S

    2016-01-01

    Quasi-periodic modulations of the stellar light curve may result from dark spots crossing the visible stellar disc. Due to differential rotation, spots at different latitudes generally have different rotation periods. Hence, by studying spot-induced modulations, one can learn about stellar surface (differential) rotation and magnetic activity. Recently, Reinhold & Arlt (2015) proposed a method based on the Lomb-Scargle periodogram of light curves to identify the sign of the differential rotation at the stellar surface. Our goal is to understand how the modulation of the stellar light curve due to the presence of spots and the corresponding periodogram are affected by both the stellar and spot properties. We generate synthetic light curves of stars with different properties (inclination angle, limb darkening, and rotation rate) and spot configurations (number of spots, latitude, intensity contrast, and size). By analysing their Lomb-Scargle periodograms, we compute the ratio between the heights of the seco...

  8. Learning styles of medical students, general surgery residents, and general surgeons: implications for surgical education

    Science.gov (United States)

    2010-01-01

    Background Surgical education is evolving under the dual pressures of an enlarging body of knowledge required during residency and mounting work-hour restrictions. Changes in surgical residency training need to be based on available educational models and research to ensure successful training of surgeons. Experiential learning theory, developed by David Kolb, demonstrates the importance of individual learning styles in improving learning. This study helps elucidate the way in which medical students, surgical residents, and surgical faculty learn. Methods The Kolb Learning Style Inventory, which divides individual learning styles into Accommodating, Diverging, Converging, and Assimilating categories, was administered to the second year undergraduate medical students, general surgery resident body, and general surgery faculty at the University of Alberta. Results A total of 241 faculty, residents, and students were surveyed with an overall response rate of 73%. The predominant learning style of the medical students was assimilating and this was statistically significant (p < 0.03) from the converging learning style found in the residents and faculty. The predominant learning styles of the residents and faculty were convergent and accommodative, with no statistically significant differences between the residents and the faculty. Conclusions We conclude that medical students have a significantly different learning style from general surgical trainees and general surgeons. This has important implications in the education of general surgery residents. PMID:20591159

  9. Learning styles of medical students, general surgery residents, and general surgeons: implications for surgical education.

    Science.gov (United States)

    Engels, Paul T; de Gara, Chris

    2010-06-30

    Surgical education is evolving under the dual pressures of an enlarging body of knowledge required during residency and mounting work-hour restrictions. Changes in surgical residency training need to be based on available educational models and research to ensure successful training of surgeons. Experiential learning theory, developed by David Kolb, demonstrates the importance of individual learning styles in improving learning. This study helps elucidate the way in which medical students, surgical residents, and surgical faculty learn. The Kolb Learning Style Inventory, which divides individual learning styles into Accommodating, Diverging, Converging, and Assimilating categories, was administered to the second year undergraduate medical students, general surgery resident body, and general surgery faculty at the University of Alberta. A total of 241 faculty, residents, and students were surveyed with an overall response rate of 73%. The predominant learning style of the medical students was assimilating and this was statistically significant (p learning style found in the residents and faculty. The predominant learning styles of the residents and faculty were convergent and accommodative, with no statistically significant differences between the residents and the faculty. We conclude that medical students have a significantly different learning style from general surgical trainees and general surgeons. This has important implications in the education of general surgery residents.

  10. Learning Curve

    Directory of Open Access Journals (Sweden)

    Mary Caponegro

    2012-01-01

    Full Text Available “What’s the matter with Mary Caponegro ?” Françoise Palleau-Papin Were I to introduce Mary Caponegro formally, in an official biographical notice, it would go something like this: Mary Caponegro is the Richard B. Fisher Family Professor in Literature and Writing at Bard College, where William Gaddis once taught. She is the author of five works of fiction: Tales from the Next Village (Lost Roads, 1985, The Star Cafe (Scribner, 1990, Five Doubts (Marsilio, 1998, The Complexities of Intimacy ...

  11. Laparoscopic colorectal surgery in learning curve: Role of implementation of a standardized technique and recovery protocol. A cohort study

    Directory of Open Access Journals (Sweden)

    Gaetano Luglio

    2015-06-01

    Conclusion: Proper laparoscopic colorectal surgery is safe and leads to excellent results in terms of recovery and short term outcomes, even in a learning curve setting. Key factors for better outcomes and shortening the learning curve seem to be the adoption of a standardized technique and training model along with the strict supervision of an expert colorectal surgeon.

  12. [Transvaginal repair of genital prolapse with Prolift: evaluation of safety and learning curve].

    Science.gov (United States)

    Bafghi, A; Iannelli, A; Verger, S; Novelas, S; Amiel, J; Gugenheim, J; Bongain, A

    2009-02-01

    Evaluation of the mini invasiveness and the learning curve of the Prolift technique. Prospective study. All patients were operated on by the same surgeon. The mini-invasiveness of the procedure was estimated through the evaluation of the intraoperative and immediate postoperative complications. The learning curve was evaluated through the analysis of the operative time. Between January and December 2007. Forty-seven patients were included in the study. Mean follow-up was: 11,8 months. Two cases of bladder injury and two cases of intraoperative bleeding (>500 ml) were reported. One case of vaginal erosion and one case of recurrence of the prolapse occurred during the follow-up. The mean operative time was 62+/-18 min. The mean operative time of the posterior step of the Prolift was 24+/-min and remained stable after the 18th procedure. The learning cure of the posterior of the procedure is longer because of the passage of the needles through the ischiorectal foramens. The technique is mini-invasive considered the low rate of intra and immediate postoperative complication and the learning curve short. Longer follow-up is needed to evaluate the efficacy of the procedure in the long term.

  13. Non-Constant Learning Rates in Retrospective Experience Curve Analyses and their Correlation to Deployment Programs

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Max [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Smith, Sarah J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sohn, Michael D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-07-16

    A key challenge for policy-makers and technology market forecasters is to estimate future technology costs and in particular the rate of cost reduction versus production volume. A related, critical question is what role should state and federal governments have in advancing energy efficient and renewable energy technologies? This work provides retrospective experience curves and learning rates for several energy-related technologies, each of which have a known history of federal and state deployment programs. We derive learning rates for eight technologies including energy efficient lighting technologies, stationary fuel cell systems, and residential solar photovoltaics, and provide an overview and timeline of historical deployment programs such as state and federal standards and state and national incentive programs for each technology. Piecewise linear regimes are observed in a range of technology experience curves, and public investments or deployment programs are found to be strongly correlated to an increase in learning rate across multiple technologies. A downward bend in the experience curve is found in 5 out of the 8 energy-related technologies presented here (electronic ballasts, magnetic ballasts, compact fluorescent lighting, general service fluorescent lighting, and the installed cost of solar PV). In each of the five downward-bending experience curves, we believe that an increase in the learning rate can be linked to deployment programs to some degree. This work sheds light on the endogenous versus exogenous contributions to technological innovation and highlights the impact of exogenous government sponsored deployment programs. This work can inform future policy investment direction and can shed light on market transformation and technology learning behavior.

  14. Learning curve of 3D fluoroscopy image-guided pedicle screw placement in the thoracolumbar spine.

    Science.gov (United States)

    Ryang, Yu-Mi; Villard, Jimmy; Obermüller, Thomas; Friedrich, Benjamin; Wolf, Petra; Gempt, Jens; Ringel, Florian; Meyer, Bernhard

    2015-03-01

    During the past decade, a disproportionate increase of spinal fusion procedures has been observed. Along with this trend, image-guided spine surgery has been experiencing a renaissance in the recent years. A wide range of different navigation systems are available on the market today. However, only few published studies assess the learning curves concerning these new spinal navigation techniques. So far, a study on the learning curve for intraoperative three-dimensional fluoroscopy (3DFL)-navigated pedicle screw (PS) placement is still lacking. The purpose of the study was to analyze the learning curve for 3DFL-navigated thoracolumbar PS placement. The study design included a prospective case series. A cohort of 145 patients were recruited from January 2011 to June 2012. The outcome measures were duration of intraoperative 3D scans, PS placement, PS accuracy on postoperative computed tomography (CT) scans, and PS-related revisions and complications. From the introduction of spinal navigation to our department in January 2011 until June 2012, the learning curve for the duration of intraoperative 3D scan acquisition (navigation or control scan) and placement time per screw, intraoperative screw revisions, screw-related complications, revision surgeries, and PS accuracy on postoperative CT scans were assessed in 145 patients undergoing dorsal navigated instrumentation for 928 PS (736 lumbosacral and 192 thoracic). The observed time span was divided into four intervals. Results of the second, third, and last periods were compared with the first (reference) period, respectively. The mean navigation 3D scan time decreased (first and fourth periods) from 15.4±7.8 (range, 4-40) to 8.4±3.3 (3-15) minutes (plearning effect was found with respect to intraoperative screw revisions. There was one revision surgery. We could demonstrate significant learning effects for 3DFL-navigated PS placement with regard to intraoperative 3D scan acquisition, PS placement time, and PS

  15. A Comparison of a Machine Learning Model with EuroSCORE II in Predicting Mortality after Elective Cardiac Surgery: A Decision Curve Analysis.

    Science.gov (United States)

    Allyn, Jérôme; Allou, Nicolas; Augustin, Pascal; Philip, Ivan; Martinet, Olivier; Belghiti, Myriem; Provenchere, Sophie; Montravers, Philippe; Ferdynus, Cyril

    2017-01-01

    The benefits of cardiac surgery are sometimes difficult to predict and the decision to operate on a given individual is complex. Machine Learning and Decision Curve Analysis (DCA) are recent methods developed to create and evaluate prediction models. We conducted a retrospective cohort study using a prospective collected database from December 2005 to December 2012, from a cardiac surgical center at University Hospital. The different models of prediction of mortality in-hospital after elective cardiac surgery, including EuroSCORE II, a logistic regression model and a machine learning model, were compared by ROC and DCA. Of the 6,520 patients having elective cardiac surgery with cardiopulmonary bypass, 6.3% died. Mean age was 63.4 years old (standard deviation 14.4), and mean EuroSCORE II was 3.7 (4.8) %. The area under ROC curve (IC95%) for the machine learning model (0.795 (0.755-0.834)) was significantly higher than EuroSCORE II or the logistic regression model (respectively, 0.737 (0.691-0.783) and 0.742 (0.698-0.785), p machine learning model, in this monocentric study, has a greater benefit whatever the probability threshold. According to ROC and DCA, machine learning model is more accurate in predicting mortality after elective cardiac surgery than EuroSCORE II. These results confirm the use of machine learning methods in the field of medical prediction.

  16. Establishing the minimal number of virtual reality simulator training sessions necessary to develop basic laparoscopic skills competence: evaluation of the learning curve.

    Science.gov (United States)

    Duarte, Ricardo Jordão; Cury, José; Oliveira, Luis Carlos Neves; Srougi, Miguel

    2013-01-01

    Medical literature is scarce on information to define a basic skills training program for laparoscopic surgery (peg and transferring, cutting, clipping). The aim of this study was to determine the minimal number of simulator sessions of basic laparoscopic tasks necessary to elaborate an optimal virtual reality training curriculum. Eleven medical students with no previous laparoscopic experience were spontaneously enrolled. They were submitted to simulator training sessions starting at level 1 (Immersion Lap VR, San Jose, CA), including sequentially camera handling, peg and transfer, clipping and cutting. Each student trained twice a week until 10 sessions were completed. The score indexes were registered and analyzed. The total of errors of the evaluation sequences (camera, peg and transfer, clipping and cutting) were computed and thereafter, they were correlated to the total of items evaluated in each step, resulting in a success percent ratio for each student for each set of each completed session. Thereafter, we computed the cumulative success rate in 10 sessions, obtaining an analysis of the learning process. By non-linear regression the learning curve was analyzed. By the non-linear regression method the learning curve was analyzed and a r2 = 0.73 (p learning curve reaches a plateau. The forward sessions in the same difficult level do not promote any improvement in laparoscopic basic surgical skills, and the students should be introduced to a more difficult training tasks level.

  17. Hand-assisted partial nephrectomy with early arterial clamp removal: Impact of the learning curve

    DEFF Research Database (Denmark)

    Azawi, Nessn H; Norus, Thomas P; Wittendorff, Hans-Erik;

    2014-01-01

    OBJECTIVE: The aims of this study were to present the results of hand-assisted laparoscopic partial nephrectomy according to the margin, ischaemia and complications system; to assess the role of the learning curve; and to compare this approach with other approaches. MATERIAL AND METHODS: Data from...... nephrectomy for complex tumours with a relatively high success rate according to the margin, ischaemia and complications system. Warm ischaemia time could be obtained within 5 min after 40 procedures....

  18. Acquisition Challenge: The Importance of Incompressibility in Comparing Learning Curve Models

    Science.gov (United States)

    2015-10-01

    of Akron, an MBA from Regis University, and a PhD in man- agement with a specialization in Organizational Behavior and Human Resource Management...environ- ment in which competition for congressional funding is higher than ever before. On an organizational level, DoD acquisition programs have...International Journal of Production Research, 33(3), 777–794. Badiru, A. (2012). Half-life learning curves in the defense acquisition life cycle. Defense ARJ

  19. The learning curve and factors affecting warm ischemia time during robot-assisted partial nephrectomy

    Directory of Open Access Journals (Sweden)

    Hitesh Dube

    2015-01-01

    Full Text Available Introduction: The learning curve for robotic partial nephrectomy was investigated for an experienced laparoscopic surgeon and factors associated with warm ischemia time (WIT were assessed. Materials and Methods: Between 2007 and 2014, one surgeon completed 171 procedures. Operative time, blood loss, complications and ischemia time were examined to determine the learning curve. The learning curve was defined as the number of procedures needed to reach the targeted goal for WIT, which most recently was 20 min. Statistical analyses including multivariable regression analysis and matching were performed. Results: Comparing the first 30 to the last 30 patients, mean ischemia time (23.0-15.2 min, P < 0.01 decreased while tumor size (2.4-3.4 cm, P = 0.02 and nephrometry score (5.9-7.0, P = 0.02 increased. Body mass index (P = 0.87, age (P = 0.38, complication rate (P = 0.16, operating time (P = 0.78 and estimated blood loss (P = 0.98 did not change. Decreases in ischemia time corresponded with revised goals in 2011 and early vascular unclamping with the omission of cortical renorrhaphy in selected patients. A multivariable analysis found nephrometry score, tumor diameter, cortical renorrhaphy and year of surgery to be significant predictors of WIT. Conclusions: Adoption of robotic assistance for a surgeon experienced with laparoscopic surgery was associated with low complication rates even during the initial cases of robot-assisted partial nephrectomy. Ischemia time decreased while no significant changes in blood loss, operating time or complications were seen. The largest decrease in ischemia time was associated with adopting evidence-based goals and new techniques, and was not felt to be related to a learning curve.

  20. Clinical experience with the first 40 cases with femtosecond laser cataract surgery technology: safety of the learning curve

    Directory of Open Access Journals (Sweden)

    Joao Crispim

    2015-10-01

    Full Text Available ABSTRACT Objective: To evaluate the introduction of the femtosecond laser (FSL to perform the key steps of the traditional cataract surgery process and the operational difficulties and safety of this new technology during routine use in an operating room in Brazil. Methods A retrospective study was conducted using the first cases operated on at a single center using the laser platform LenSx/Alcon with a soft contact lens patient interface.All patients underwent a detailed preoperative assessment.The anterior capsulotomy, nuclear fragmentation, and corneal incisions were created with the FSL; then, the surgery was completed following the standard phacoemulsification procedure. The main outcome measurements were difficulties and complications related to the learning curve and an analysis of postoperative uncorrected distance visual acuity (UDVA. Results: Of 31 patients (40 eyes, 9 patients had FSL cataract surgery in both eyes.The mean age was 64 ± 12 years (ranging from 42 to 82, the mean cataract nuclear sclerosis was grading 2 ± 0.6 (ranging from 1 to 4, and the preoperative mean UDVA in logMAR was 0.4 ± 0.2 (ranging from 0.1 to 1.3. Anterior capsulotomy was complete in all patients, and scissors were not needed to cut off any intact portion. The postoperative corneal incisions were not completely linear and showed some irregularities. Laser phaco-fragmentation was effective, with the division of the nucleus into smaller segments easily performed before phacoemulsification.After 1 month, the postoperative mean UDVA in logMAR was 0.1 ± 0.1 (ranging from 0.0 to 0.4 (P < 0.0001. Conclusion: With increasing surgical cases and experience, the phacoemulsification steps are performed precisely and effectively with FSL pretreatment, resulting in a safe learning curve.

  1. Application of the Learning Curve Analysis to the LHC Main Dipole Production First Assessment

    CERN Document Server

    Fessia, P; Rossi, L

    2006-01-01

    About two third of the LHC main dipoles have been delivered by the three suppliers charged of the production. The training of the staff, mostly hired just for this manufacture, and the natural improvement of the procedures with the acquired experience, decrease naturally the time necessary for the assembly of a unit. The aim of this paper is to apply methodologies like the cost-based learning curves and the time-based learning curves to the LHC Main Dipole comparing the estimated learning percentage to the ones experienced in other industries. This type of analysis, still in a preliminary phase and here applied to about 40% of the total production of the LHC magnets that will end by 2006, shows that our production has a relatively high learning percentage and it is similar to aerospace and complex machine tools for new models. Therefore with the LHC project, accelerator magnets seem to have reached industrial maturity and this production can be used as bench mark for other large scientific projects implying s...

  2. Starspot signature on the light curve. Learning about the latitudinal distribution of spots

    Science.gov (United States)

    Santos, A. R. G.; Cunha, M. S.; Avelino, P. P.; García, R. A.; Mathur, S.

    2017-02-01

    Context. Quasi-periodic modulations of the stellar light curve may result from dark spots crossing the visible stellar disc. Owing to differential rotation, spots at different latitudes generally have different rotation periods. Hence, by studying spot-induced modulations, it is possible to learn about stellar surface (differential) rotation and magnetic activity. Recently, a method based on the Lomb-Scargle periodogram of light curves has been proposed to identify the sign of the differential rotation at the stellar surface. Aims: Our goal is to understand how the modulation of the stellar light curve due to the presence of spots and the corresponding periodogram are affected by both the stellar and spot properties. Methods: We generate synthetic light curves of stars with different properties (inclination angle, limb darkening, and rotation rate) and spot configurations (number of spots, latitude, intensity contrast, and size). By analysing their Lomb-Scargle periodograms, we compute the ratio between the heights of the second and first harmonics of the rotation period (peak-height ratio). Results: We find that the peak-height ratios are essentially a function of a single parameter, the fraction of time the spot is visible, which is related to the sinusoidality of the spot modulation. We identify the conditions under which the periodogram analysis can actually provide an estimate of the spot latitudes and/or the stellar inclination angle. We also identify possible sources of error in the identification of the sign of the differential rotation.

  3. Learning curves and long-term outcome of simulation-based thoracentesis training for medical students

    Directory of Open Access Journals (Sweden)

    Chen Kezhong

    2011-06-01

    Full Text Available Abstract Background Simulation-based medical education has been widely used in medical skills training; however, the effectiveness and long-term outcome of simulation-based training in thoracentesis requires further investigation. The purpose of this study was to assess the learning curve of simulation-based thoracentesis training, study skills retention and transfer of knowledge to a clinical setting following simulation-based education intervention in thoracentesis procedures. Methods Fifty-two medical students were enrolled in this study. Each participant performed five supervised trials on the simulator. Participant's performance was assessed by performance score (PS, procedure time (PT, and participant's confidence (PC. Learning curves for each variable were generated. Long-term outcome of the training was measured by the retesting and clinical performance evaluation 6 months and 1 year, respectively, after initial training on the simulator. Results Significant improvements in PS, PT, and PC were noted among the first 3 to 4 test trials (p 0.05. Clinical competency in thoracentesis was improved in participants who received simulation training relative to that of first year medical residents without such experience (p Conclusions This study demonstrates that simulation-based thoracentesis training can significantly improve an individual's performance. The saturation of learning from the simulator can be achieved after four practice sessions. Simulation-based training can assist in long-term retention of skills and can be partially transferred to clinical practice.

  4. Hierarchical linear modeling of California Verbal Learning Test--Children's Version learning curve characteristics following childhood traumatic head injury.

    Science.gov (United States)

    Warschausky, Seth; Kay, Joshua B; Chi, PaoLin; Donders, Jacobus

    2005-03-01

    California Verbal Learning Test-Children's Version (CVLT-C) indices have been shown to be sensitive to the neurocognitive effects of traumatic brain injury (TBI). The effects of TBI on the learning process were examined with a growth curve analysis of CVLT-C raw scores across the 5 learning trials. The sample with history of TBI comprised 86 children, ages 6-16 years, at a mean of 10.0 (SD=19.5) months postinjury; 37.2% had severe injury, 27.9% moderate, and 34.9% mild. The best-fit model for verbal learning was with a quadratic function. Greater TBI severity was associated with lower rate of acquisition and more gradual deceleration in the rate of acquisition. Intelligence test index scores, previously shown to be sensitive to severity of TBI, were positively correlated with rate of acquisition. Results provide evidence that the CVLT-C learning slope is not a simple linear function and further support for specific effects of TBI on verbal learning. ((c) 2005 APA, all rights reserved).

  5. Comprehensive and innovative techniques for livertransplantation in rats: A surgical guide

    Institute of Scientific and Technical Information of China (English)

    Tomohide; Hori; Justin; H; Nguyen; Yasuhiro; Ogura; Toshiyuki; Hata; Shintaro; Yagi; Ann-Marie; T; Baine; Norifumi; Ohashi; Christopher; B; Eckman; Aimee; R; Herdt; Hiroto; Egawa; Yasutsugu; Takada; Fumitaka; Oike; Seisuke; Saka-moto; Mureo; Kasahara; Kohei; Ogawa; Koichiro; Hata; Taku; Iida; Yukihide; Yonekawa; Lena; Sibulesky; Kagemasa; Kuribayashi; Takuma; Kato; Kanako; Saito; Mie; Torii; Naruhiko; Sahara; Naoko; Kamo; Tomoko; Sahara; Motohiko; Yasutomi; Shinji; Uemoto

    2010-01-01

    AIM: To investigate our learning curves of orthotopic liver transplantation (OLT) in rats and the most important factor for successful surgery. METHODS: We describe the surgical procedures for our rat OLT model, and determined the operator learning curves. The various factors that contributed to successful surgery were determined. The most important surgical factors were evaluated between successful and unsuccessful surgeries.RESULTS: Learning curve data indicated that 50 cases were required for operator tr...

  6. Endoscopic tympanoplasty: learning curve for a surgeon already trained in microscopic tympanoplasty.

    Science.gov (United States)

    Doğan, Sedat; Bayraktar, Cem

    2017-04-01

    The aim of this study was to evaluate the learning curve of endoscopic tympanoplasty for a surgeon already trained in microscopic tympanoplasty. We analyzed the clinical records of 81 patients who underwent transcanal endoscopic type 1 tympanoplasty and 30 control patients who underwent microscopic tympanoplasty between 2013 and 2015 in a tertiary hospital. All operations were performed by a single surgeon already trained in microscopic tympanoplasty. Patients were divided into four groups according to the date of surgery chronologically (group 1 early stage, group 2 intermediate stage, group 3 advanced stage and group 4 control). We evaluated the four groups according to surgery duration, audiometric results, and graft intake success. The operation duration shortened in accordance with the surgeon's experience and there were two subsequent steps during the learning curve: first, after 30 procedures; and second, after 60 procedures. The mean operation duration was 88.60 ± 21.10 min in group 1, and 62.00 ± 12.48 min in group 2. After 60 procedures, the mean operation duration was 43.81 ± 8.34 min in group 3. In the control group, the microscopic tympanoplasty duration was 69.93 ± 12.56 min. When we compared audiologic results (air conduction, bone conduction, and air-bone gap) and graft intake success rates, there were no significant differences between groups. Endoscopic tympanoplasty is a minimally invasive and effective technique. Mastering endoscopic tympanoplasty takes approximately 60 operations for a surgeon already trained in microscopic tympanoplasty. Graft intake success rates and hearing results are stable during the learning curve.

  7. Evaluation of the learning curve for transcatheter aortic valve implantation via the transfemoral approach.

    Science.gov (United States)

    Arai, Takahide; Lefèvre, Thierry; Hovasse, Thomas; Hayashida, Kentaro; Watanabe, Yusuke; O'Connor, Stephen A; Benamer, Hakim; Garot, Philippe; Cormier, Bertrand; Bouvier, Erik; Morice, Marie-Claude; Chevalier, Bernard

    2016-01-15

    The aim of this study was to evaluate the learning curve in performing transfemoral TAVI (TF-TAVI). Between October 2006 and October 2013, 312 consecutive TF-TAVI cases performed by 6 interventional cardiologists, using the Edwards Sapien valve and 104 using the CoreValve, were included in the present analysis. Cumulative sum (CUSUM) failure analysis of combined 30-day safety endpoint was used to evaluate learning curves. The CUSUM analysis revealed a learning curve regarding the occurrence of 30-day adverse events with an improvement after the initial 86 cases using the Edwards valve and 40 cases using the CoreValve. We divided the Edwards valve cases into two groups (early experience: Cases 1 to 86; late experience: Cases 87 to 312). The rate of 30-day mortality and 1-year mortality significantly decreased in the late experience group (17% to 7%, p=0.019; 34% to 21%, p=0.035, respectively). We divided the CoreValve cases into two groups (early experience: Cases 1 to 40; late experience: Cases 41 to 104). The rate of 30-day mortality and 1-year mortality significantly decreased in the late experience group (20% to 6%, p=0.033; 38% to 15%, p=0.040, respectively). The groups including both valves were also analyzed after propensity-matching (early [n=52] vs late [n=52]). This model also showed that 30-day and 1-year mortality rates were significantly lower in the late experience group (13% to 1%, p=0.028; 34% to 20%, p=0.042, respectively). An appropriate level of experience is needed to reduce the complication rate and mortality in TF-TAVI. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  8. [Learning curve in laparoscopic Roux-en-Y gastric bypass for the treatment of morbid obesity].

    Science.gov (United States)

    Ben David, Matan; Maler, Ilanit; Kashtan, Hanoch; Keidar, Andrei

    2015-04-01

    Laparoscopic Roux-en-Y gastric bypass (LRYGB) is currently considered the gold standard treatment for morbid obesity. The learning curve for this procedure is about 100 cases, and it is considered the most important factor in decreasing complications and mortality. We present our experience and learning curve with LRYGB. The data was collected prospectively. All patients with primary LRYGB between March 2006 and April 2014 were included. Only patients with full data on demographics, length of stay, operating time, and complications were included in the study. Five hundred and eleven patients underwent a LRYGB. Ninety five of them underwent a redo RYGB (conversion), and were excluded. Of the remaining 416 patients, full data was available for 326 and the statistical analysis refers to this group. The complication rate was available for all patients who were included in the study. The mean age and body mass index were 43 years (14-76 years) and 42.8 kg/m2 (34-76) respectively. The mean duration of surgery was 86 minutes (40-420). In the first 100 patients, operating time was 148 min, while in the last 125 patients it was 75 min. The major perioperative complication rate was 7.7%. Of 4 leaks (0.95%, 3 were encountered in the first 100 operations, and one in the following 316 (3% and 0.3% respectively). The mean length of stay was 2.2 days (1-46). None of the patients stayed in the intensive care unit. There was no mortality. LRYGB is very safe. We confirm that the learning curve for this procedure is more than 100 cases. Appropriate training is crucial.

  9. Learning curve and interobserver variance in quantification of the optical coherence tomography attenuation coefficient.

    Science.gov (United States)

    Wessels, Ronni; de Bruin, Daniel M; Faber, Dirk J; Sanders, Joyce; Vincent, Andrew D; van Beurden, Marc; van Leeuwen, Ton G; Ruers, Theo J M

    2015-01-01

    The learning curve and interobserver variance of attenuation coefficient (μOCT ) determination from optical coherence tomography (OCT) images were quantified. The μOCT of normal and diseased vulvar tissues was determined at five time points by three novice students and three OCT experts who reached consensus for reference. Students received feedback between time points. Eventually, variance in μOCT was smaller in images of diseased tissue than in images of normal vulvar tissue. The difference between the consensus and student μOCT values was larger for smaller values of μOCT . We conclude that routine μOCT determination for tissue classification does not require extensive training.

  10. Cognitive learning and its future in urology: surgical skills teaching and assessment.

    Science.gov (United States)

    Shafiei, Somayeh B; Hussein, Ahmed A; Guru, Khurshid A

    2017-07-01

    The aim of this study is to provide an overview of the current status of novel cognitive training approaches in surgery and to investigate the potential role of cognitive training in surgical education. Kinematics of end-effector trajectories, as well as cognitive state features of surgeon trainees and mentors have recently been studied as modalities to objectively evaluate the expertise level of trainees and to shorten the learning process. Virtual reality and haptics also have shown promising in research results in improving the surgical learning process by providing feedback to the trainee. 'Cognitive training' is a novel approach to enhance training and surgical performance. The utility of cognitive training in improving motor skills in other fields, including sports and rehabilitation, is promising enough to justify its utilization to improve surgical performance. However, some surgical procedures, especially ones performed during human-robot interaction in robot-assisted surgery, are much more complicated than sport and rehabilitation. Cognitive training has shown promising results in surgical skills-acquisition in complicated environments such as surgery. However, these methods are mostly developed in research groups using limited individuals. Transferring this research into the clinical applications is a demanding challenge. The aim of this review is to provide an overview of the current status of these novel cognitive training approaches in surgery and to investigate the potential role of cognitive training in surgical education.

  11. A learning curve-based method to implement multifunctional work teams in the Brazilian footwear sector.

    Science.gov (United States)

    Guimarães, L B de M; Anzanello, M J; Renner, J S

    2012-05-01

    This paper presents a method for implementing multifunctional work teams in a footwear company that followed the Taylor/Ford system for decades. The suggested framework first applies a Learning Curve (LC) modeling to assess whether rotation between tasks of different complexities affects workers' learning rate and performance. Next, the Macroergonomic Work Analysis (MA) method (Guimarães, 1999, 2009) introduces multifunctional principles in work teams towards workers' training and resources improvement. When applied to a pilot line consisting of 100 workers, the intervention-reduced work related accidents in 80%, absenteeism in 45.65%, and eliminated work related musculoskeletal disorders (WMSD), medical consultations, and turnover. Further, the output rate of the multifunctional team increased average 3% compared to the production rate of the regular lines following the Taylor/Ford system (with the same shoe model being manufactured), while the rework and spoilage rates were reduced 85% and 69%, respectively.

  12. From curve fitting to machine learning an illustrative guide to scientific data analysis and computational intelligence

    CERN Document Server

    Zielesny, Achim

    2016-01-01

    This successful book provides in its second edition an interactive and illustrative guide from two-dimensional curve fitting to multidimensional clustering and machine learning with neural networks or support vector machines. Along the way topics like mathematical optimization or evolutionary algorithms are touched. All concepts and ideas are outlined in a clear cut manner with graphically depicted plausibility arguments and a little elementary mathematics. The major topics are extensively outlined with exploratory examples and applications. The primary goal is to be as illustrative as possible without hiding problems and pitfalls but to address them. The character of an illustrative cookbook is complemented with specific sections that address more fundamental questions like the relation between machine learning and human intelligence. All topics are completely demonstrated with the computing platform Mathematica and the Computational Intelligence Packages (CIP), a high-level function library developed with M...

  13. Learning styles of first-year orthopedic surgical residents at 1 accredited institution.

    Science.gov (United States)

    Caulley, Lisa; Wadey, Veronica; Freeman, Risa

    2012-01-01

    This study represents 1 arm of a 5-year prospective study investigating the learning styles of orthopedic residents and their surgical educators. This project investigates the learning styles of the 2009-2010 year 1 orthopedic surgical residents. A cross-sectional survey using the Kolb Learning Style Inventory was completed by 13 first year orthopedic residents. Direct 1-to-1 interviews were completed with the primary investigator and each participant using the Kolb Learning Style Inventory and learning styles were determined. Converging learning style was the most common among the residents (53.8%). Residents demonstrated a high tendency toward the learning skill of abstract conceptualization combined with active experimentation, and a transition from action-oriented to more reflective learning style with age and postgraduate education. These results may be useful in creating strategies specific to each learning style that will be offered to residents to enhance future teaching and learning. Copyright © 2012 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

  14. The future of regional anesthesia education: lessons learned from the surgical specialty.

    Science.gov (United States)

    Niazi, Ahtsham U; Peng, Philip W; Ho, Melissa; Tiwari, Akhilesh; Chan, Vincent W

    2016-08-01

    Application of ultrasound in regional anesthesia has now become the standard of care and its use has shown to reduce complications. Nevertheless, gaining expertise in ultrasound-guided regional anesthesia requires the acquisition of new cognitive and technical skills. In addition, due to a reduction in resident working hours and enforcement of labour laws and directives across various states and countries, trainees perform and witness fewer procedures. Together, these issues create challenges in the teaching and learning of ultrasound-guided regional anesthesia in the time-based model of learning. The challenges of teaching ultrasound-guided regional anesthesia are similar to those experienced by our surgical counterparts with the advent of minimally invasive surgery. In order to overcome these challenges, our surgical colleagues used theories of surgical skills training, simulation, and the concept of deliberate practice and feedback to shift the paradigm of learning from experience-based to competency-based learning. In this narrative review, we describe the theory behind the evolution of surgical skills training. We also outline how we can apply these learning theories and simulation models to a competency-based curriculum for training in ultrasound-guided regional anesthesia.

  15. Establishing learning curve for Tenckhoff catheter insertion by interventional nephrologist using CUSUM analysis: how many procedures and in which situation?

    Science.gov (United States)

    Goh, Bak Leong; Ganeshadeva Yudisthra, M; Lim, Teck Onn

    2009-01-01

    Peritoneal dialysis (PD) catheter insertion success rate is known to vary among different operators, and peritoneoscope PD catheter insertion demands mastery of a steep learning curve. Defining a learning curve using a continuous monitoring tool such as a Cumulative Summation (CUSUM) chart is useful for planning training programs. We aimed to analyze the learning curve of a trainee nephrologist in performing peritoneoscope PD catheter implantation with CUSUM chart. This was a descriptive single-center study using collected data from all PD patients who underwent peritoneoscope PD catheter insertion in our hospital. CUSUM model was used to evaluate the learning curve for peritoneoscope PD catheter insertion. Unacceptable primary failure rate (i.e., catheter malfunction within 1 month of insertion) was defined at >40% and acceptable performance was defined at CUSUM chart showed the learning curve of a trainee in acquiring new skill. As the trainee became more skillful with training, the CUSUM curve flattened. Technical proficiency of the trainee nephrologist in performing peritoneoscope Tenckhoff catheter insertion (CUSUM charting as described to monitor primary catheter dysfunction (i.e., failure of catheter function within 1 month of insertion), primary leak (i.e., within 1 month of catheter insertion), and primary peritonitis (i.e., within 2 weeks of catheter insertion).

  16. Effects of the Learning Curve on Efficacy of Radiofrequency Ablation for Barrett's Esophagus.

    Science.gov (United States)

    Pasricha, Sarina; Cotton, Cary; Hathorn, Kelly E; Li, Nan; Bulsiewicz, William J; Wolf, W Asher; Muthusamy, V Raman; Komanduri, Srinadh; Wolfsen, Herbert C; Pruitt, Ron E; Ertan, Atilla; Chmielewski, Gary W; Shaheen, Nicholas J

    2015-10-01

    Complete eradication of Barrett's esophagus (BE) often requires multiple sessions of radiofrequency ablation (RFA). Little is known about the effects of case volume on the safety and efficacy of RFA or about the presence or contour of learning curves for this procedure. We collected data from the US RFA Patient Registry (from 148 institutions) for patients who underwent RFA for BE from July 2007 to July 2011. We analyzed the effects of the number of patients treated by individual endoscopists and individual centers on safety and efficacy outcomes of RFA. Outcomes, including stricture, bleeding, hospitalization, and complete eradication of intestinal metaplasia (CEIM), were assessed using logistic regression. The effects of center and investigator experience on numbers of treatment sessions to achieve CEIM were examined using linear regression. After we controlled for potential confounders, we found that as the experience of endoscopists and centers increased with cases, the numbers of treatment sessions required to achieve CEIM decreased. This relationship persisted after adjusting for patient age, sex, race, length of BE, and presence of pretreatment dysplasia (P .05). Based on analysis of a large multicenter registry, efficiency of the treatment, as measured by number of sessions needed to achieve CEIM, increased with case volume, indicating a learning curve effect. This trend began to disappear after treatment of approximately 30 patients by the center or individual endoscopist. However, there was no significant association between safety or efficacy outcomes and previous case volume. Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights reserved.

  17. Learning curve in cryoballoon ablation of atrial fibrillation: eight-year experience.

    Science.gov (United States)

    Wójcik, Maciej; Berkowitsch, Alexander; Greis, Harald; Zaltsberg, Sergey; Hamm, Christian W; Pitschner, Heinz F; Kuniss, Malte; Neumann, Thomas

    2014-01-01

    We analyzed the procedural experience cryoballoon ablation (CBA) of atrial fibrillation (AF) gained over 8 years in a high-volume centre to understand the influence of the learning curve on feasibility, safety and clinical outcome. In 424 patients (62% male) with drug-refractory AF, CBA was performed between 2005 and 2012. The analyzed period was divided into 8 calendar years. The endpoint of the study was arrhythmia recurrence after the 3-month blanking period in the 1-year follow-up since the index procedure, in the absence of anti-arrhythmic drugs class I and III. A combined AF type, Left Atrium size, Renal insufficiency, MEtabolic syndrome, cardiomyopathy (ALARMEc) risk score was calculated for each patient. The overall 1-year success rate of a single CBA was 73%. Continuous increase in 1-year success rate was observed with successive years of the study. The gradual improvement in outcome was related to gradual fall in ALARMEc risk score in successive patients. A continuous decrease in fluoroscopy and procedure time was observed in each subsequent year. CBA, followed by the proper selection of patients, facilitates a satisfactory outcome, especially in patients at an early stage of PV-trigger-dependent AF. Still, as with each new technology, it requires completion of a learning curve.

  18. Mood Extraction Using Facial Features to Improve Learning Curves of Students in E-Learning Systems

    Directory of Open Access Journals (Sweden)

    Abdulkareem Al-Alwani

    2016-11-01

    Full Text Available Students’ interest and involvement during class lectures is imperative for grasping concepts and significantly improves academic performance of the students. Direct supervision of lectures by instructors is the main reason behind student attentiveness in class. Still, there is sufficient percentage of students who even under direct supervision tend to lose concentration. Considering the e-learning environment, this problem is aggravated due to absence of any human supervision. This calls for an approach to assess and identify lapses of attention by a student in an e-learning session. This study is carried out to improve student’s involvement in e-learning platforms by using their facial feature to extract mood patterns. Analyzing themoods based on emotional states of a student during an online lecture can provide interesting results which can be readily used to improvethe efficacy of content delivery in an e-learning platform. A survey is carried out among instructors involved in e-learning to identify most probable facial features that represent the facial expressions or mood patterns of a student. A neural network approach is used to train the system using facial feature sets to predict specific facial expressions. Moreover, a data association based algorithm specifically for extracting information on emotional states by correlating multiple sets of facial features is also proposed. This framework showed promising results in inciting student’s interest by varying the content being delivered.Different combinations of inter-related facial expressions for specific time frames were used to estimate mood patterns and subsequently level of involvement of a student in an e-learning environment.The results achieved during the course of research showed that mood patterns of a student provide a good correlation with his interest or involvement during online lectures and can be used to vary the content to improve students’ involvement in the e-learning

  19. Informal self-regulated learning on a surgical rotation: uncovering student experiences in context.

    Science.gov (United States)

    Woods, Nicole N; Mylopoulos, Maria; Brydges, Ryan

    2011-12-01

    The ability to guide one's own learning is an essential skill for the health professional. The apprenticeship model of undergraduate education offers an opportunity to engage in self-regulated learning as students work to set goals, evaluate the available opportunities and seek out those with the greatest potential for learning. A close examination of how students navigate their clinical rotations could therefore foster greater understanding of how students learn to guide their own learning. The study presented here aimed to examine undergraduate medical students' day-to-day learning strategies in order to better understand the process of informal self-regulated learning in practice. As a secondary objective, we sought to provide a forum for students to share and critically reflect on their own self-regulated learning strategies. A series of focus groups were conducted with medical students on a surgical rotation. Participants were asked to discuss issues relating to the strategies and behaviours that they had implemented in order to maximize their educational experience. Three distinct approaches to informal self-regulated learning were identified: Participants articulated tendencies to acquiesce to a perceived lack of learning opportunities choose from available learning opportunities and create their own learning opportunities. The results are interpreted through the lens of self-regulated learning theory and implications for medical education are discussed.

  20. Establishing the minimal number of virtual reality simulator training sessions necessary to develop basic laparoscopic skills competence: evaluation of the learning curve

    Directory of Open Access Journals (Sweden)

    Ricardo Jordao Duarte

    2013-09-01

    Full Text Available Introduction Medical literature is scarce on information to define a basic skills training program for laparoscopic surgery (peg and transferring, cutting, clipping. The aim of this study was to determine the minimal number of simulator sessions of basic laparoscopic tasks necessary to elaborate an optimal virtual reality training curriculum. Materials and Methods Eleven medical students with no previous laparoscopic experience were spontaneously enrolled. They were submitted to simulator training sessions starting at level 1 (Immersion Lap VR, San Jose, CA, including sequentially camera handling, peg and transfer, clipping and cutting. Each student trained twice a week until 10 sessions were completed. The score indexes were registered and analyzed. The total of errors of the evaluation sequences (camera, peg and transfer, clipping and cutting were computed and thereafter, they were correlated to the total of items evaluated in each step, resulting in a success percent ratio for each student for each set of each completed session. Thereafter, we computed the cumulative success rate in 10 sessions, obtaining an analysis of the learning process. By non-linear regression the learning curve was analyzed. Results By the non-linear regression method the learning curve was analyzed and a r2 = 0.73 (p < 0.001 was obtained, being necessary 4.26 (∼five sessions to reach the plateau of 80% of the estimated acquired knowledge, being that 100% of the students have reached this level of skills. From the fifth session till the 10th, the gain of knowledge was not significant, although some students reached 96% of the expected improvement. Conclusions This study revealed that after five simulator training sequential sessions the students' learning curve reaches a plateau. The forward sessions in the same difficult level do not promote any improvement in laparoscopic basic surgical skills, and the students should be introduced to a more difficult training

  1. Development Process and Technical Aspects of Laparoscopic Hepatectomy: Learning Curve Based on 15 Years of Experience.

    Science.gov (United States)

    Komatsu, Shohei; Scatton, Olivier; Goumard, Claire; Sepulveda, Ailton; Brustia, Raffaele; Perdigao, Fabiano; Soubrane, Olivier

    2017-05-01

    Laparoscopic hepatectomy continues to be a challenging operation associated with a steep learning curve. This study aimed to evaluate the learning process during 15 years of experience with laparoscopic hepatectomy and to identify approaches to standardization of this procedure. Prospectively collected data of 317 consecutive laparoscopic hepatectomies performed from January 2000 to December 2014 were reviewed retrospectively. The operative procedures were classified into 4 categories (minor hepatectomy, left lateral sectionectomy [LLS], left hepatectomy, and right hepatectomy), and indications were classified into 5 categories (benign-borderline tumor, living donor, metastatic liver tumor, biliary malignancy, and hepatocellular carcinoma). During the first 10 years, the procedures were limited mainly to minor hepatectomy and LLS, and the indications were limited to benign-borderline tumor and living donor. Implementation of major hepatectomy rapidly increased the proportion of malignant tumors, especially hepatocellular carcinoma, starting from 2011. Conversion rates decreased with experience for LLS (13.3% vs 3.4%; p = 0.054) and left hepatectomy (50.0% vs 15.0%; p = 0.012), but not for right hepatectomy (41.4% vs 35.7%; p = 0.661). Our 15-year experience clearly demonstrates the stepwise procedural evolution from LLS through left hepatectomy to right hepatectomy, as well as the trend in indications from benign-borderline tumor/living donor to malignant tumors. In contrast to LLS and left hepatectomy, a learning curve was not observed for right hepatectomy. The ongoing development process can contribute to faster standardization necessary for future advances in laparoscopic hepatectomy. Copyright © 2017 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

  2. Promoting Inter-Professional Teamwork and Learning--The Case of a Surgical Operating Theatre

    Science.gov (United States)

    Collin, Kaija; Paloniemi, Susanna; Mecklin, Jukka-Pekka

    2010-01-01

    Hospitals, and surgical operating theatres (OTs) in particular, are environments in which inter-professional teamwork and learning are essential to secure patient safety and effective practice. However, it has been revealed in many studies that inter-professional collaborative work in hospital organisations faces many challenges and constraints.…

  3. General surgical interns contributing to the clerkship learning environment of medical students.

    Science.gov (United States)

    Yu, Tzu-Chieh; Lemanu, Daniel P; Henning, Marcus; Maccormick, Andrew D; Hawken, Susan J; Hill, Andrew G

    2013-08-01

    Junior doctors are increasingly promoted as clinical teachers but there is limited understanding of how they contribute to medical student clerkship learning. To describe contributions made by general surgical interns to the student clerkship learning environment. The mixed-methods study involved two focus groups attended by volunteer interns and Year 4 students, and a student questionnaire collecting quantitative data. Focus group transcripts were evaluated using a qualitative analysis system. Six interns and five students attended focus groups in June and August 2011. Qualitative analysis found that intern contributions to student learning can be grouped under four distinct roles: physician, supervisor, teacher and person. Data from 85 questionnaires (response rate 57%) revealed that intern-student encounters occurred daily in the surgical wards and emergency department. Interns demonstrated bedside procedures, clerical/administrative tasks and interpretation of laboratory and radiological investigations. Appreciated for approachability, friendliness and ability to relate to students, interns also played a crucial role in integrating students into the surgical team. This significantly correlated to clerkship enjoyment. Surgical interns improve clerkship learning environments by demonstrating "personal" skills such as friendliness, approachability and relatedness. This has important implications for preparing interns as clinical preceptors.

  4. CUSUM analysis of learning curves for the head-mounted microscope in phonomicrosurgery.

    Science.gov (United States)

    Chen, Ting; Vamos, Andrew C; Dailey, Seth H; Jiang, Jack J

    2016-10-01

    To observe the learning curve of the head-mounted microscope in a phonomicrosurgery simulator using cumulative summation (CUSUM) analysis, which incorporates a magnetic phonomicrosurgery instrument tracking system (MPTS). Retrospective case series. Eight subjects (6 medical students and 2 surgeons inexperienced in phonomicrosurgery) operated on phonomicrosurgical simulation cutting tasks while using the head-mounted microscope for 400 minutes total. Two 20-minute sessions occurred each day for 10 total days, with operation quality (Qs ) and completion time (T) being recorded after each session. Cumulative summation analysis of Qs and T was performed by using subjects' performance data from trials completed using a traditional standing microscope as success criteria. The motion parameters from the head-mounted microscope were significantly better than the standing microscope (P microscope (P microscope, as assessed by CUSUM analysis. Cumulative summation analysis can objectively monitor the learning process associated with a phonomicrosurgical simulator system, ultimately providing a tool to assess learning status. Also, motion parameters determined by our MPTS showed that, although the head-mounted microscope provides better motion control, worse Qs and longer T resulted. This decrease in Qs is likely a result of the relatively unstable visual environment that it provides. Overall, the inexperienced surgeons participating in this study failed to adapt to the head-mounted microscope in our simulated phonomicrosurgery environment. 4 Laryngoscope, 126:2295-2300, 2016. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

  5. Learning curve of computer-assisted navigation system in spine surgery

    Institute of Scientific and Technical Information of China (English)

    BAI Yu-shu; ZHANG Ye; CHEN Zi-qiang; WANG Chuan-feng; ZHAO Ying-chuan; SHI Zhi-cai; LI Ming; LIU Ka Po Gabriel

    2010-01-01

    Background Spine surgery using computer-assisted navigation (CAN) has been proven to result in low screw misplacement rates, low incidence of radiation exposure and excellent operative field viewing versus the conventional intraoperative image intensifier (CⅢ). However, as we know, few previous studies have described the learning curve of CAN in spine surgery.Methods We performed two consecutive case cohort studies on pedicel screw accuracy and operative time of two spine surgeons with different experience backgrounds, A and B, in one institution during the same period. Lumbar pedicel screw cortical perforation rate and operative time of the same kind of operation using CAN were analyzed and compared using CⅢ for the two surgeons at initial, 6 months and 12 months of CAN usage.Results CAN spine surgery had an overall lower cortical perforation rate and less mean operative time compared with CⅢ for both surgeon A and B cohorts when total cases of four years were included. It missed being statistically significant,with 3.3% versus 4.7% (P=0.191) and 125.7 versus 132.3 minutes (P=0.428) for surgeon A and 3.6% versus 6.4%(P=0.058), and 183.2 versus 213.2 minutes (P=0.070) for surgeon B. in an attempt to demonstrate the learning curve,the cases after 6 months of the CAN system in each surgeon's cohort were compared. The perforation rate decreased by 2.4% (P=0.039) and 4.3% (P=0.003) and the operative time was reduced by 31.8 minutes (P=0.002) and 14.4 minutes (P=0.026) for the CAN groups of surgeons A and B, respectively. When only the cases performed after 12 months using the CAN system were considered, the perforation rate decreased by 3.9% (P=0.006) and 5.6% (P <0.001) and the operative time was reduced by 20.9 minutes (P <0.001) and 40.3 minutes (P <0.001) for the CAN groups of surgeon A and B, respectively.Conclusions In the long run, CAN spine surgery decreased the lumbar screw cortical perforation rate and operative time. The learning curve showed a

  6. Development of the Mathematics of Learning Curve Models for Evaluating Small Modular Reactor Economics

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, T. J. [ORNL

    2014-02-01

    The cost of nuclear power is a straightforward yet complicated topic. It is straightforward in that the cost of nuclear power is a function of the cost to build the nuclear power plant, the cost to operate and maintain it, and the cost to provide fuel for it. It is complicated in that some of those costs are not necessarily known, introducing uncertainty into the analysis. For large light water reactor (LWR)-based nuclear power plants, the uncertainty is mainly contained within the cost of construction. The typical costs of operations and maintenance (O&M), as well as fuel, are well known based on the current fleet of LWRs. However, the last currently operating reactor to come online was Watts Bar 1 in May 1996; thus, the expected construction costs for gigawatt (GW)-class reactors in the United States are based on information nearly two decades old. Extrapolating construction, O&M, and fuel costs from GW-class LWRs to LWR-based small modular reactors (SMRs) introduces even more complication. The per-installed-kilowatt construction costs for SMRs are likely to be higher than those for the GW-class reactors based on the property of the economy of scale. Generally speaking, the economy of scale is the tendency for overall costs to increase slower than the overall production capacity. For power plants, this means that doubling the power production capacity would be expected to cost less than twice as much. Applying this property in the opposite direction, halving the power production capacity would be expected to cost more than half as much. This can potentially make the SMRs less competitive in the electricity market against the GW-class reactors, as well as against other power sources such as natural gas and subsidized renewables. One factor that can potentially aid the SMRs in achieving economic competitiveness is an economy of numbers, as opposed to the economy of scale, associated with learning curves. The basic concept of the learning curve is that the more a

  7. Development of the Mathematics of Learning Curve Models for Evaluating Small Modular Reactor Economics

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, T. J. [ORNL

    2014-02-01

    The cost of nuclear power is a straightforward yet complicated topic. It is straightforward in that the cost of nuclear power is a function of the cost to build the nuclear power plant, the cost to operate and maintain it, and the cost to provide fuel for it. It is complicated in that some of those costs are not necessarily known, introducing uncertainty into the analysis. For large light water reactor (LWR)-based nuclear power plants, the uncertainty is mainly contained within the cost of construction. The typical costs of operations and maintenance (O&M), as well as fuel, are well known based on the current fleet of LWRs. However, the last currently operating reactor to come online was Watts Bar 1 in May 1996; thus, the expected construction costs for gigawatt (GW)-class reactors in the United States are based on information nearly two decades old. Extrapolating construction, O&M, and fuel costs from GW-class LWRs to LWR-based small modular reactors (SMRs) introduces even more complication. The per-installed-kilowatt construction costs for SMRs are likely to be higher than those for the GW-class reactors based on the property of the economy of scale. Generally speaking, the economy of scale is the tendency for overall costs to increase slower than the overall production capacity. For power plants, this means that doubling the power production capacity would be expected to cost less than twice as much. Applying this property in the opposite direction, halving the power production capacity would be expected to cost more than half as much. This can potentially make the SMRs less competitive in the electricity market against the GW-class reactors, as well as against other power sources such as natural gas and subsidized renewables. One factor that can potentially aid the SMRs in achieving economic competitiveness is an economy of numbers, as opposed to the economy of scale, associated with learning curves. The basic concept of the learning curve is that the more a

  8. Kant, curves and medical learning practice: a reply to Le Morvan and Stock.

    Science.gov (United States)

    Ives, J

    2007-02-01

    In a recent paper published in the Journal of Medical Ethics, Le Morvan and Stock claim that the kantian ideal of treating people always as ends in themselves and never merely as a means is in direct and insurmountable conflict with the current medical practice of allowing practitioners at the bottom of their "learning curve" to "practise their skills" on patients. In this response, I take up the challenge they issue [corrected] and try to reconcile this conflict. The kantian ideal offered in the paper is an incomplete characterisation of Kant's moral philosophy, and the formula of humanity is considered in isolation without taking into account other salient kantian principles. I also suggest that their argument based on "necessary for the patient" assumes too narrow a reading of "necessary". This reply is intended as an extension to, rather than a criticism of, their work.

  9. Space-Filling Curves as a Novel Crystal Structure Representation for Machine Learning Models

    CERN Document Server

    Jasrasaria, Dipti; Rappoport, Dmitrij; Aspuru-Guzik, Alan

    2016-01-01

    A fundamental problem in applying machine learning techniques for chemical problems is to find suitable representations for molecular and crystal structures. While the structure representations based on atom connectivities are prevalent for molecules, two-dimensional descriptors are not suitable for describing molecular crystals. In this work, we introduce the SFC-M family of feature representations, which are based on Morton space-filling curves, as an alternative means of representing crystal structures. Latent Semantic Indexing (LSI) was employed in a novel setting to reduce sparsity of feature representations. The quality of the SFC-M representations were assessed by using them in combination with artificial neural networks to predict Density Functional Theory (DFT) single point, Ewald summed, lattice, and many-body dispersion energies of 839 organic molecular crystal unit cells from the Cambridge Structural Database that consist of the elements C, H, N, and O. Promising initial results suggest that the S...

  10. Digital tomosynthesis for evaluating metastatic lung nodules: Nodule visibility, learning curves, and reading times

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Hee; Goo, Jin Mo; Lee, Sang Min; Park, Chang Min; Bahn, Young Eun; Kim, Hyung Jin; Song, Yong Sub; Hwang, Eui Jin [Dept. of Radiology, Seoul National University College of Medicine, and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul (Korea, Republic of)

    2015-04-15

    To evaluate nodule visibility, learning curves, and reading times for digital tomosynthesis (DT). We included 80 patients who underwent computed tomography (CT) and DT before pulmonary metastasectomy. One experienced chest radiologist annotated all visible nodules on thin-section CT scans using computer-aided detection software. Two radiologists used CT as the reference standard and retrospectively graded the visibility of nodules on DT. Nodule detection performance was evaluated in four sessions of 20 cases each by six readers. After each session, readers were unblinded to the DT images by revealing the true-positive markings and were instructed to self-analyze their own misreads. Receiver-operating-characteristic curves were determined. Among 414 nodules on CT, 53.3% (221/414) were visible on DT. The main reason for not seeing a nodule on DT was small size (93.3%, < or = 5 mm). DT revealed a substantial number of malignant nodules (84.1%, 143/170). The proportion of malignant nodules among visible nodules on DT was significantly higher (64.7%, 143/221) than that on CT (41.1%, 170/414) (p < 0.001). Area under the curve (AUC) values at the initial session were > 0.8, and the average detection rate for malignant nodules was 85% (210/246). The inter-session analysis of the AUC showed no significant differences among the readers, and the detection rate for malignant nodules did not differ across sessions. A slight improvement in reading times was observed. Most malignant nodules > 5 mm were visible on DT. As nodule detection performance was high from the initial session, DT may be readily applicable for radiology residents and board-certified radiologists.

  11. CUSUM method for construction of trainee spinal ultrasound learning curves following standardised teaching.

    Science.gov (United States)

    Deacon, A J; Melhuishi, N S; Terblanche, N C S

    2014-07-01

    Spinal ultrasonography is a promising aid for epidural insertion. We aimed to determine the learning curve of spinal ultrasonography tasks and the number of training scans required to reach competency after undergoing standardised step-wise teaching. Trainees were required to complete a minimum of 60 assessed scans on selected non-pregnant models following attendance at two training sessions, with feedback from an expert after each scan. Learning curves were plotted using the non-risk cumulative summation technique and an acceptable failure rate of 20%. Five trainees completed between 65 and 75 scans each. All trainees were competent at identifying a randomly assigned intervertebral space after a median of five scans (range one to nine) and at measuring the depth from skin to the posterior complex after a median of 10 scans (range 1 to 42). Two trainees were competent at marking an ideal needle insertion point after 55 scans, while three trainees did not attain competency. All trainees were competent after 60 scans if the tolerance was changed from five to eight millimetre for marking the needle insertion point. The average time taken to complete a scan was 163 seconds. Our study showed that after a standardised educational intervention, anaesthetic trainees are able to identify a lumbar interlaminar space easily and can measure the depth to the posterior complex after a reasonable number of additional practice scans, but experienced difficulty accurately marking the needle insertion point whilst using spinal ultrasonography. We confirmed that it was hard to achieve competency in all aspects of spinal ultrasonography, based on assessment using our predefined competency criteria.

  12. The single surgeon learning curve of laparoscopic liver resection: A continuous evolving process through stepwise difficulties.

    Science.gov (United States)

    Tomassini, Federico; Scuderi, Vincenzo; Colman, Roos; Vivarelli, Marco; Montalti, Roberto; Troisi, Roberto Ivan

    2016-10-01

    The aim of the study was to evaluate the single-surgeon learning curve (SSLC) in laparoscopic liver surgery over an 11-year period with risk-adjusted (RA) cumulative sum control chart analysis.Laparoscopic liver resection (LLR) is a challenging and highly demanding procedure. No specific data are available for defining the feasibility and reproducibility of the SSLC regarding a consistent and consecutive caseload volume over a specified time period.A total of 319 LLR performed by a single surgeon between June 2003 and May 2014 were retrospectively analyzed. A difficulty scale (DS) ranging from 1 to 10 was created to rate the technical difficulty of each LLR. The risk-adjusted cumulative sum control chart (RA-CUSUM) analysis evaluated conversion rate (CR), operative time (OT) and blood loss (BL). Perioperative morbidity and mortality were also analyzed.The RA-CUSUM analysis of the DS identified 3 different periods: P1 (n = 91 cases), with a mean DS of 3.8; P2 (cases 92-159), with a mean DS of 5.3; and P3 (cases 160-319), with a mean DS of 4.7. P2 presented the highest conversion and morbidity rates with a longer OT, whereas P3 showed the best results (P analysis, at least 160 cases (P3) are needed to complete the SSLC performing safely different types of LLR. A minimum of 50 cases can provide a significant decrease in BL. Based on these findings, a longer learning curve should be anticipated to broaden the indications for LLR.

  13. A quality improvement study on avoidable stressors and countermeasures affecting surgical motor performance and learning.

    Science.gov (United States)

    Conrad, Claudius; Konuk, Yusuf; Werner, Paul D; Cao, Caroline G; Warshaw, Andrew L; Rattner, David W; Stangenberg, Lars; Ott, Harald C; Jones, Daniel B; Miller, Diane L; Gee, Denise W

    2012-06-01

    To explore how the 2 most important components of surgical performance--speed and accuracy-are influenced by different forms of stress and what the impact of music is on these factors. On the basis of a recently published pilot study on surgical experts, we designed an experiment examining the effects of auditory stress, mental stress, and music on surgical performance and learning and then correlated the data psychometric measures to the role of music in a novice surgeon's life. Thirty-one surgeons were recruited for a crossover study. Surgeons were randomized to 4 simple standardized tasks to be performed on the SurgicalSIM VR laparoscopic simulator (Medical Education Technologies, Inc, Sarasota, FL), allowing exact tracking of speed and accuracy. Tasks were performed under a variety of conditions, including silence, dichotic music (auditory stress), defined classical music (auditory relaxation), and mental loading (mental arithmetic tasks). Tasks were performed twice to test for memory consolidation and to accommodate for baseline variability. Performance was correlated to the brief Musical Experience Questionnaire (MEQ). Mental loading influences performance with respect to accuracy, speed, and recall more negatively than does auditory stress. Defined classical music might lead to minimally worse performance initially but leads to significantly improved memory consolidation. Furthermore, psychologic testing of the volunteers suggests that surgeons with greater musical commitment, measured by the MEQ, perform worse under the mental loading condition. Mental distraction and auditory stress negatively affect specific components of surgical learning and performance. If used appropriately, classical music may positively affect surgical memory consolidation. It also may be possible to predict surgeons' performance and learning under stress through psychological tests on the role of music in a surgeon's life. Further investigation is necessary to determine the

  14. [Prospective evaluation of the direct costs of prostate enucleation by the HoLEP(®) laser during the learning curve period].

    Science.gov (United States)

    Roger, M; Goris-Gbenou, M; Guillermet, A; Vial, R; Cunin, N; Tomas, J; Bourgue, L; Combe, M; Lopez, J-G; Combe, C

    2017-04-01

    Holmium laser enucleation of the prostate (HoLEP) has been shown to be effective in treating large prostates compared to prostate transurethral resection (TURP). There are no published data evaluating specifically the impact of the learning curve on the direct costs of HoLEP. The objective of this study was to evaluate the direct costs generated by the use of HoLEP laser during the learning curve period. The costs of all medical devices (DM) and drugs used, pre- and post-operative parameters during surgery have been prospectively collected between March and October 2016. A total of 32 patients were included in the study with a mean age of 70.8 years and a mean prostate volume of 68.6 cm(3). The mean cost of anesthesia was 39.0 € and that of drugs and DM used for surgery was 257.95 € but could reach 470.76 € in case of conversion to bipolar resection. The mean duration of enucleation and morcellation was 150minutes with a mean weight of enucleated specimens of 40.4g. The total mean duration of patient care was 197minutes at an estimated hourly cost of € 636. Despite some limitations, this study makes it possible to analyze the direct costs of the management of benign prostatic hypertrophy using HoLEP, an innovative surgical technique, and to specify that these costs are more related to bipolar conversion and voluminous adenomas especially during the learning curve. 5. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  15. Learning Curves in Pediatric Minimally Invasive Surgery: A Systematic Review of the Literature and a Framework for Reporting.

    Science.gov (United States)

    Macdonald, Alexander L; Haddad, Munther; Clarke, Simon A

    2016-08-01

    There exists a learning curve (LC) with the adoption of any minimally invasive surgical (MIS) technique with implications for training, implementation, and evaluation. A standardized approach to describing and analyzing LCs in pediatric MIS is lacking. We sought to determine how pediatric MIS LCs are quantified and present a framework for reporting. Systematic search of MEDLINE and EMBASE 1985-October 2015 for articles describing MIS in the pediatric population and presenting formal analysis of the LC. Articles screened by two independent reviewers. Twenty-nine articles (n = 17 general abdominal/thoracic, n = 12 urological) from an 18-year period (1997-2015) were included representing 3345 procedures (n = 3116 laparoscopic, n = 10 thoracoscopic, n = 219 robotic). Seven (24%) were prospective, three multicenter. Twenty-two (76%) presented data pertaining to >1 operating surgeon. Operative time was the most commonly employed surrogate of proficiency (n = 26 [90%] studies). Twenty (69%) described >1 LC outcome measure. Sixteen additional measures were described, including conversion (n = 12 studies); blood loss (n = 4 studies); complications (n = 10 studies); and postoperative outcomes (n = 14 studies). Three studies assessed impact of LC on trainees and one considered economic impact. LCs were presented in tabular form (n = 14 studies) and graphically (n = 19). Eleven (38%) studies undertook statistical appraisal utilizing comparative statistics (n = 8 studies) and regression analysis (n = 4 studies). Multiple outcome measures of proficiency are employed in reporting pediatric MIS experience and analysis of LCs is inconsistent. A standardized multioutcome approach to reporting should be encouraged. In addition, attempts should be made to quantify the impact on trainee involvement. We present an idealized framework for reporting.

  16. Incidence of Complications During the Surgeon Learning Curve Period for Primary Total Ankle Replacement: A Systematic Review.

    Science.gov (United States)

    Simonson, Devin C; Roukis, Thomas S

    2015-10-01

    Surgeons performing primary total ankle replacement have achieved outcomes comparable to ankle arthrodesis. However, while many reports exist suggesting the presence of a surgeon learning curve period during initial performance of primary total ankle replacement, no published analysis of the actual incidence of complications encountered during this period exists. Therefore, we sought to provide such an analysis through systematic review. A total of 2453 primary total ankle replacements with 1085 complications (44.2%) were identified. Our results revealed conflicting data whether an acceptably low incidence of high-grade complications leading to total ankle replacement failure exists during the surgeon learning curve period.

  17. Does Prior Laparoscopic and Open Surgery Experience Have Any Impact on Learning Curve in Transition to Robotic Surgery?

    Directory of Open Access Journals (Sweden)

    Cüneyt Adayener

    2016-12-01

    Full Text Available It has been 15 years since the Food And Drug Administration approved the Da Vinci® robotic surgery system. Robotic applications are being used extensively in urology, particularly in radical prostatectomy. Like all high-tech products, this system also has a high cost and a steep learning curve, therefore, preventing it from becoming widespread. There are various studies on the effect of open surgery or laparoscopy experience on the learning curve of robotic surgery. Analyzing these interactions well will provide valuable information on making the training period of robotic system more efficient.

  18. Learning Curves of Macintosh Laryngoscope in Nurse Anesthetist Trainees Using Cumulative Sum Method

    Directory of Open Access Journals (Sweden)

    Panthila Rujirojindakul

    2014-01-01

    Full Text Available Background. Tracheal intubation is a potentially life-saving procedure. This skill is taught to many anesthetic healthcare professionals, including nurse anesthetists. Our goal was to evaluate the learning ability of nurse anesthetist trainees in their performance of orotracheal intubation with the Macintosh laryngoscope. Methods. Eleven nurse anesthetist trainees were enrolled in the study during the first three months of their training. All trainees attended formal lectures and practice sessions with manikins at least one time on performing successful tracheal intubation under supervision of anesthesiology staff. Learning curves for each nurse anesthetist trainee were constructed with the standard cumulative summation (cusum methods. Results. Tracheal intubation was attempted on 388 patients. Three hundred and six patients (78.9% were successfully intubated on the trainees’ first attempt and 17 patients (4.4% on the second attempt. The mean ± SD number of orotracheal intubations per trainee was 35.5 ± 5.1 (range 30–47. Ten (90.9% of 11 trainees crossed the 20% acceptable failure rate line. A median of 22 procedures was required to achieve an 80% orotracheal intubations success rate. Conclusion. At least 22 procedures were required to reach an 80% success rate for orotracheal intubation using Macintosh laryngoscope in nonexperienced nurse anesthetist trainees.

  19. LHC Run 2 – reaching the top of the learning curve

    CERN Multimedia

    2015-01-01

    As the LHC Physics conference gets underway in St Petersburg, it’s a good time to take stock of where things stand with Run 2.    For all those involved with operating the LHC and its experiments in this new energy and intensity regime, 2015 was always going to be a learning curve. And learning we most certainly are. The main objective for this year has always been to set up the machine and experiments for production running at high energy and high intensity in 2016, 17 and 18.  That said, the experiments have all been able to collect quality data at 13 TeV, with the first Run 2 papers and conference presentations being written and delivered this summer. It would be unfair of me, however, to give the impression that it’s all been plain sailing. As well as the highs: smooth recommissioning of the machine, physics getting underway, and a successful transition to 25-nanosecond bunch spacing, we’ve also had our fair share of lows. There have been no sho...

  20. Learning curve of laparoscopy-assisted distal gastrectomy with systemic lymphadenectomy for early gastric cancer

    Institute of Scientific and Technical Information of China (English)

    Min-Chan Kim; Ghap-Joong Jung; Hyung-Ho Kim

    2005-01-01

    AIM: To evaluate the nature of the "learning curve" for laparoscopy-assisted distal gastrectomy (LADG) with systemic lymphadenectomy for early gastric cancer. METHODS: The data of 90 consecutive patients with early gastric cancer who underwent LADG with systemic lymphadenectomy between April 2003 and November 2004 were reviewed. The 90 patients were divided into 9 sequential groups of 10 cases in each group and the average operative time of these 9 groups were determined. Other learning indicators, such as transfusion requirements, conversion rates to open surgery, postoperative complication, time to first flatus, and postoperative hospital stay, were evaluated. RESULTS: After the first 10 LADGs, the operative time reached its first plateau (230-240 min/operation) and then reached a second plateau (<200 min/operation) for the final 30 cases. Although a significant improvement in the operative time was noted after the first 50 cases, there were no significant differences in transfusion requirements, conversion rates to open surgery, postoperative complications, time to first flatus, or postoperative hospital stay between the groups. CONCLUSION: Based on operative time analysis, this study show that experience of 50 cases of LADG with systemic lymphadenectomy for early gastric cancer is required to achieve optimum proficiency.

  1. Resident training in urology: Bipolar transurethral resection of the prostate - a safe method in learning endoscopic surgical procedure

    Directory of Open Access Journals (Sweden)

    Alessandro Del Rosso

    2013-06-01

    Full Text Available Introduction: Modern medicine uses increasingly innovative techniques that require more and more capabilities for acquisition. In the urological department is increasing the presence of patients with lower urinary tract symptoms (LUTS and transurethral resection of the prostate (TURP is the standard of care in their surgical treatment. We report our surgical experience and learning curve of using bipolar plasmakinetic devices in the training of urological residents to benign prostatic hyperplasia (BPH treatment. Materials and Methods: 80 patients with benign prostatic enlargement due to BPH were enrolled in the study. TURP has been performed by three urological residents and by an expe- rienced urologist. Patients were evaluated before and 6 months after the endoscopic bipolar plasmakinetic resection using the International Prostate Symptom Score (IPSS, maximum uri- nary flow rate (Qmax, postvoid residual urine (PVR and prostate specific antigen (PSA. Results: Overall 60 procedures were performed, 18 PlasmaKinetic (PK-TURP procedures were completed by the three residents. In the other 42 cases the procedures were completed by the experienced urologist. In eight cases there was a capsular perforation and the experienced urol- ogist replaced the resident to complete the resection. No complications have been reported in the procedures completed by the senior urologist. All complications caused by the residents were man- aged intraoperatively without changing the course of the procedure. Statistical differences were observed regarding IPSS, quality of life (QoL, and PVR at 6-month follow-up when procedures completed by urological residents were compared to those completed by the senior urologist. Conclusion: Bipolar device represents appropriate tools to acquire endoscopic skills. It is safe and it can be used at the first experience of BPH treatment by a resident who has not previ- ously approached this endoscopic surgical procedure.

  2. [Web-based education: learning surgical procedures step-by-step with 3D visualization].

    Science.gov (United States)

    van der Velde, Susanne; Maljers, Jaap; Wiggers, Theo

    2014-01-01

    There is a need for more uniform, structured education focused on surgical procedures. We offer a standardized, step-by-step, web-based procedural training method with which surgeons can train more interns efficiently. The basis of this learning method is formed by 3D films in which surgical procedures are performed in clearly defined steps and the anatomic structures behind the surgical operating planes are further dissected. This basis is supported by online modules in which, aside from the operation, preparation and postoperative care are also addressed. Registrars can test their knowledge with exams. Trainers can see what the registrars studied, how they scored and how they progressed with their clinical skills. With the online portfolio we offer building blocks for certification and accreditation. With this clearly structured research method of constant quality, registrars are less dependent on the local trainer. In addition, through better preparation, the operation capacity can be used more efficiently for the training.

  3. Impact of obesity on laparoscopic-assisted left colectomy in different stages of the learning curve.

    Science.gov (United States)

    Sarli, Leopoldo; Rollo, Alessio; Cecchini, Stefano; Regina, Gabriele; Sansebastiano, Giuliano; Marchesi, Federico; Veronesi, Licia; Ferro, Michelina; Roncoroni, Luigi

    2009-04-01

    This study is aimed at verifying if the surgeon's experience has an impact on the risk of conversion to open surgery of laparoscopic left colectomy performed in obese patients. A multiple logistic regression analysis was performed of 181 laparoscopic left hemicolectomies completed between April 2001 and June 2006. The results were analysed statistically in relation to the learning curve, by comparing factors that could have had an impact on the risk of conversion in the first 91 cases and in the last 90 cases. The overall conversion rate was 11%. Only weight level was found to be predictive of conversion to open surgery. No death was observed. Sixteen patients presented postoperative complications (8.8%), with no significant differences between obese and nonobese patients (P=0.95). The conversion rate was higher in the group of the first 91 cases: 15.6% versus 6.6% (P=0.05). Average body mass index of converted patients resulted as being higher than that of nonconverted ones (29.97+/-3.76 vs. 25.48+/-3.72; Plearning curve, but the difference was not observed during the second period (P=0.87). On multiple logistic regression analysis, obesity was found to be predictive of conversion only during the first period. The data indicate that the laparoscopic colorectal surgery is feasible and effective in obese patients both when the surgeon is expert in laparoscopic colorectal resection and at the initial phase of the experience. At the initial phase of the experience obesity constitutes a higher risk of conversion to open surgery.

  4. Digital tomosynthesis for evaluating metastatic lung nodules: nodule visibility, learning curves, and reading times.

    Science.gov (United States)

    Lee, Kyung Hee; Goo, Jin Mo; Lee, Sang Min; Park, Chang Min; Bahn, Young Eun; Kim, Hyungjin; Song, Yong Sub; Hwang, Eui Jin

    2015-01-01

    To evaluate nodule visibility, learning curves, and reading times for digital tomosynthesis (DT). We included 80 patients who underwent computed tomography (CT) and DT before pulmonary metastasectomy. One experienced chest radiologist annotated all visible nodules on thin-section CT scans using computer-aided detection software. Two radiologists used CT as the reference standard and retrospectively graded the visibility of nodules on DT. Nodule detection performance was evaluated in four sessions of 20 cases each by six readers. After each session, readers were unblinded to the DT images by revealing the true-positive markings and were instructed to self-analyze their own misreads. Receiver-operating-characteristic curves were determined. Among 414 nodules on CT, 53.3% (221/414) were visible on DT. The main reason for not seeing a nodule on DT was small size (93.3%, ≤ 5 mm). DT revealed a substantial number of malignant nodules (84.1%, 143/170). The proportion of malignant nodules among visible nodules on DT was significantly higher (64.7%, 143/221) than that on CT (41.1%, 170/414) (p 0.8, and the average detection rate for malignant nodules was 85% (210/246). The inter-session analysis of the AUC showed no significant differences among the readers, and the detection rate for malignant nodules did not differ across sessions. A slight improvement in reading times was observed. Most malignant nodules > 5 mm were visible on DT. As nodule detection performance was high from the initial session, DT may be readily applicable for radiology residents and board-certified radiologists.

  5. Intersphincteric resection for very low rectal cancer: clinical outcomes of open versus laparoscopic approach and multidimensional analysis of the learning curve for laparoscopic surgery.

    Science.gov (United States)

    Kuo, Li-Jen; Hung, Chin-Sheng; Wang, Weu; Tam, Ka-Wai; Lee, Hung-Chia; Liang, Hung-Hua; Chang, Yu-Jia; Huang, Ming-Te; Wei, Po-Li

    2013-08-01

    Laparoscopic rectal cancer surgery is regarded as more complex because of its technical difficulties in pelvic exposure, dissection, and sphincter preservation. This study therefore aimed to investigate the feasibility of laparoscopic resection for low rectal cancer using intersphincteric resection (ISR) and to assess its short-term oncological outcomes. Further, we intended to analyze the learning curve for laparoscopic surgery and identify the factors influencing the learning curve. Patients with low rectal cancer who received open or laparoscopic ISR were retrospectively chart reviewed. The surgical and oncological outcomes were evaluated. Comparisons of operating time, estimated blood loss, surgical outcomes, and histopathologic status were analyzed. Also, operating time was used as a technical indicator for learning curve analysis. The mean estimated blood loss was 265 mL (range, 100-800 mL) in the open group and 104 mL (range, 30-250 mL) in the laparoscopic group. There was a significant difference between these two groups (P analysis showed that the mean operating time was 402.1 min (range, 210-570 min) in the first stage and 331.4 min (range, 210-450 min) in the second stage, and on pathologic examination the mean number of lymph nodes harvested was 11.1 (range, 5-21) in the first stage and 18.3 (range, 11-31) in the second stage, with statistical differences between these two stages (P = 0.034 and P = 0.004, respectively). Multifactorial analysis showed that operating time was associated with surgeons' experience (<18 or ≥18 cases) (odds ratio = 2.918, 95% CI 1.078-7.902). Protective stoma creation was also associated with surgeons' experience (odds ratio = 3.999, 95% CI 1.153-13.86). Our data show that laparoscopic ISR for low rectal cancer is feasible and safe. Surgeons' experience improved operating time and postoperative complications. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. da Vinci Skills Simulator for Assessing Learning Curve and Criterion-based Training of Robotic Basic Skills

    NARCIS (Netherlands)

    Brinkman, W.M.; Luursema, J.M.; Kengen, B.; Schout, B.M.; Witjes, J.A.; Bekkers, R.L.M.

    2013-01-01

    OBJECTIVE: To answer 2 research questions: what are the learning curve patterns of novices on the da Vinci skills simulator parameters and what parameters are appropriate for criterion-based robotic training. MATERIALS AND METHODS: A total of 17 novices completed 2 simulator sessions within 3 days.

  7. Self-organizing adaptive map: autonomous learning of curves and surfaces from point samples.

    Science.gov (United States)

    Piastra, Marco

    2013-05-01

    Competitive Hebbian Learning (CHL) (Martinetz, 1993) is a simple and elegant method for estimating the topology of a manifold from point samples. The method has been adopted in a number of self-organizing networks described in the literature and has given rise to related studies in the fields of geometry and computational topology. Recent results from these fields have shown that a faithful reconstruction can be obtained using the CHL method only for curves and surfaces. Within these limitations, these findings constitute a basis for defining a CHL-based, growing self-organizing network that produces a faithful reconstruction of an input manifold. The SOAM (Self-Organizing Adaptive Map) algorithm adapts its local structure autonomously in such a way that it can match the features of the manifold being learned. The adaptation process is driven by the defects arising when the network structure is inadequate, which cause a growth in the density of units. Regions of the network undergo a phase transition and change their behavior whenever a simple, local condition of topological regularity is met. The phase transition is eventually completed across the entire structure and the adaptation process terminates. In specific conditions, the structure thus obtained is homeomorphic to the input manifold. During the adaptation process, the network also has the capability to focus on the acquisition of input point samples in critical regions, with a substantial increase in efficiency. The behavior of the network has been assessed experimentally with typical data sets for surface reconstruction, including suboptimal conditions, e.g. with undersampling and noise.

  8. "Alarm-corrected" ergonomic armrest use could improve learning curves of novices on robotic simulator.

    Science.gov (United States)

    Yang, Kun; Perez, Manuela; Hossu, Gabriela; Hubert, Nicolas; Perrenot, Cyril; Hubert, Jacques

    2017-01-01

    In robotic surgery, the professional ergonomic habit of using an armrest reduces operator fatigue and increases the precision of motion. We designed and validated a pressure surveillance system (PSS) based on force sensors to investigate armrest use. The objective was to evaluate whether adding an alarm to the PSS system could shorten ergonomic training and improve performance. Twenty robot and simulator-naïve participants were recruited and randomized in two groups (A and B). The PSS was installed on a robotic simulator, the dV-Trainer, to detect contact with the armrest. The Group A members completed three tasks on the dV-Trainer without the alarm, making 15 attempts at each task. The Group B members practiced the first two tasks with the alarm and then completed the final tasks without the alarm. The simulator provided an overall score reflecting the trainees' performance. We used the new concept of an "armrest load" score to describe the ergonomic habit of using the armrest. Group B had a significantly higher performance score (p alarm associated with the PSS rectified ergonomic errors and accelerated professional ergonomic habit acquisition. The combination of the PSS and alarm is effective in significantly shortening the learning curve in the robotic training process.

  9. Reliability assessment of a manual-based procedure towards learning curve modeling and fmea analysis

    Directory of Open Access Journals (Sweden)

    Gustavo Rech

    2013-03-01

    Full Text Available Separation procedures in drug Distribution Centers (DC are manual-based activities prone to failures such as shipping exchanged, expired or broken drugs to the customer. Two interventions seem as promising in improving the reliability in the separation procedure: (i selection and allocation of appropriate operators to the procedure, and (ii analysis of potential failure modes incurred by selected operators. This article integrates Learning Curves (LC and FMEA (Failure Mode and Effect Analysis aimed at reducing the occurrence of failures in the manual separation of a drug DC. LCs parameters enable generating an index to identify the recommended operators to perform the procedures. The FMEA is then applied to the separation procedure carried out by the selected operators in order to identify failure modes. It also deployed the traditional FMEA severity index into two sub-indexes related to financial issues and damage to company´s image in order to characterize failures severity. When applied to a drug DC, the proposed method significantly reduced the frequency and severity of failures in the separation procedure.

  10. Evaluating the Learning Curve for Percutaneous Nephrolithotomy under Total Ultrasound Guidance.

    Directory of Open Access Journals (Sweden)

    Yan Song

    Full Text Available To investigate the learning curve of percutaneous nephrolithotomy under total ultrasound guidance.One hundred and twenty consecutive PCNL operations under total ultrasound guidance performed by a novice surgeon in a tertiary referral center were studied. Operations were analyzed in cohorts of 15 to determine when a plateau was reached for the variables such as operation duration, ultrasound screening time, tract dilation time, stone-free rate and complication rate. Comparison was made with the results of a surgeon who had performed more than 1000 PCNLs. Fluoroscopy was not used at all during procedure.The mean operation time dropped from 82.5 min for the first 15 patients to a mean of 64.7 min for cases 46 through 60(P = 0.047. The ultrasound screening time was a peak of 6.4 min in the first 15 cases, whereas it dropped to a mean of 3.9 min for cases 46 through 60(P = 0.01. The tract dilation time dropped from 4.9 min for the first 15 patients to a mean of 3.8 min for cases 46 through 60(P = 0.036. The senior surgeon had a mean operating time, screening time and tract dilation time equivalent to those of the novice surgeon after 60 cases. There was no significant difference in stone free rate and complication rate.The competence of ultrasound guided PCNL is reached after 60 cases with good stone free rate and without major complications.

  11. Learning curve and short-term results with a short-stem CFP system.

    Science.gov (United States)

    Pons, Miquel

    2010-01-01

    In conservative hip replacement it is important to remove only pathological tissue to preserve as much healthy bone as possible. The collum femoris preserving (CFP) system preserves the femoral neck and metaphyseal cancellous bone. We present our learning curve with this system and our preliminary results and conclusions. During 2001-2009 we placed 138 CFP prostheses in 90 men and 38 women (10 bilateral). The mean age of the patients was 57.1 years (range 22-76 years) and the mean follow-up 38.3 months. Seventy-three patients were active workers at the time of surgery. All patients began partial weight bearing at 24-36 hours and total weight bearing was allowed at 3 weeks postoperative. We have had 1 infection, 2 intraoperative partial shaft fractures that did not require treatment, 1 acetabular loosening, and 2 periprosthetic traumatic fractures treated by osteosynthesis in one case and femoral revision in the other. All but 3 active workers returned to work and 54.5% of the studied patients practice some sport or physical activity. The stem size was correct in 125 hips. Resorption at the prosthetic rim was found in 9 out of 134 hips. No clinical symptoms were found in these patients. There have been no stem revisions for aseptic loosening in the follow-up study. Although the current follow-up is too short to allow definitive conclusions, the CFP system has provided excellent short-term results.

  12. Training Performance in Diagnosis of Congenital Uterine Anomalies With 3-Dimensional Sonography: A Learning Curve Cumulative Summation Analysis.

    Science.gov (United States)

    Pascual, M Angela; Alcazar, Juan Luís; Graupera, Betlem; Rodriguez, Ignacio; Guerriero, Stefano; Mallafre, Anna; de Lorenzo, Cristina; Hereter, Lourdes

    2016-12-01

    We evaluated learning curve cumulative summation (CUSUM) of 3-dimensional (3D) sonography for diagnosis of congenital uterine anomalies and the deviations of the level of trainees' performance at the control-stage CUSUM. First-year (R1), second-year (R2), and third-year (R3) residents in obstetrics and gynecology received a training program to learn how to analyze 3D sonographic volumes and to classify congenital uterine anomalies. Each trainee worked on 155 3D sonographic volumes from preselected patients. Their results were evaluated by learning curve CUSUM and standard CUSUM. The time for each volume analysis was calculated for the expert examiner and the trainees. Trainees R1, R2, and R3 reached competence at the 85th, 58th, and 40th evaluations, respectively, with success rates of 80%, 81%, and 85%, and kept the process under control with error levels of less than 4.5% until the end of the test. The trainees significantly reduced the average time of the evaluation per volume (P < .001). Learning curve CUSUM provided quantitative indicators of the learning evolution of 3D sonography for diagnosis of congenital uterine anomalies by obstetrics and gynecology residents. The training received by the residents was adequate for diagnosis of congenital uterine anomalies using 3D sonography. © 2016 by the American Institute of Ultrasound in Medicine.

  13. The Impact of Learning Curve Model Selection and Criteria for Cost Estimation Accuracy in the DoD

    Science.gov (United States)

    2016-04-30

    qÜáêíÉÉåíÜ=^ååì~ä= ^Åèìáëáíáçå=oÉëÉ~êÅÜ= póãéçëáìã= qÜìêëÇ~ó=pÉëëáçåë= sçäìãÉ=ff= = The Impact of Learning Curve Model Selection and Criteria for Cost...Assistant Division Director, Institute for Defense Analyses Bruce Harmon, Research Staff Member, Institute for Defense Analyses The Impact of Learning ...Army Contracting Command ^Åèìáëáíáçå=oÉëÉ~êÅÜ=mêçÖê~ãW= `êÉ~íáåÖ=póåÉêÖó=Ñçê=fåÑçêãÉÇ=`Ü~åÖÉ= - 469 - The Impact of Learning Curve Model

  14. Training models in laparoscopy: a systematic review comparing their effectiveness in learning surgical skills.

    Science.gov (United States)

    Willaert, W; Van De Putte, D; Van Renterghem, K; Van Nieuwenhove, Y; Ceelen, W; Pattyn, P

    2013-01-01

    Surgery has traditionally been learned on patients in the operating room, which is time-consuming, can have an impact on the patient outcomes, and is of variable effectiveness. As a result, surgical training models have been developed, which are compared in this systematic review. We searched Pubmed, CENTRAL, and Science Citation index expanded for randomised clinical trials and randomised cross-over studies comparing laparoscopic training models. Studies comparing one model with no training were also included. The reference list of identified trials was searched for further relevant studies. Fifty-eight trials evaluating several training forms and involving 1591 participants were included (four studies with a low risk of bias). Training (virtual reality (VR) or video trainer (VT)) versus no training improves surgical skills in the majority of trials. Both VR and VT are as effective in most studies. VR training is superior to traditional laparoscopic training in the operating room. Outcome results for VR robotic simulations versus robot training show no clear difference in effectiveness for either model. Only one trial included human cadavers and observed better results versus VR for one out of four scores. Contrasting results are observed when robotic technology is compared with manual laparoscopy. VR training and VT training are valid teaching models. Practicing on these models similarly improves surgical skills. A combination of both methods is recommended in a surgical curriculum. VR training is superior to unstructured traditional training in the operating room. The reciprocal effectiveness of the other models to learn surgical skills has not yet been established.

  15. Are Surgeons Born or Made? A Comparison of Personality Traits and Learning Styles Between Surgical Trainees and Medical Students.

    Science.gov (United States)

    Preece, Ryan A; Cope, Alexandra C

    2016-01-01

    Medical students and surgical trainees differ considerably in both their preferential learning styles and personality traits. This study compares the personality profiles and learning styles of surgical trainees with a cohort of medical students specifically intent on pursuing a surgical career. A cross-sectional study was conducted contrasting surgical trainees with medical students specifying surgical career intent. The 50-item International Personality Item Pool Big-Five Factor Marker (FFM) questionnaire was used to score 5 personality domains (extraversion, conscientiousness, agreeableness, openness to experience, and neuroticism). The 24-item Learning Style Inventory (LSI) Questionnaire was used to determine the preferential learning styles (visual, auditory, or tactile). χ(2) Analysis and independent samples t-test were used to compare LSI and FFM scores, respectively. Surgical trainees from several UK surgical centers were contrasted to undergraduate medical students. A total of 53 medical students who had specifically declared desire to pursue a surgical career and were currently undertaking an undergraduate intercalated degree in surgical sciences were included and contrasted to 37 UK core surgical trainees (postgraduate years 3-4). The LSI questionnaire was completed by 53 students and 37 trainees. FFM questionnaire was completed by 29 medical students and 34 trainees. No significant difference for learning styles preference was detected between the 2 groups (p = 0.139), with the visual modality being the preferred learning style for both students and trainees (69.8% and 54.1%, respectively). Neuroticism was the only personality trait to differ significantly between the 2 groups, with medical students scoring significantly higher than trainees (2.9 vs. 2.6, p = 0.03). Medical students intent on pursuing a surgical career exhibit similar personality traits and learning styles to surgical trainees, with both groups preferring the visual learning modality

  16. Utility of Interobserver Agreement Statistics in Establishing Radiology Resident Learning Curves During Self-directed Radiologic Anatomy Training.

    Science.gov (United States)

    Tureli, Derya; Altas, Hilal; Cengic, Ismet; Ekinci, Gazanfer; Baltacioglu, Feyyaz

    2015-10-01

    The aim of the study was to ascertain the learning curves for the radiology residents when first introduced to an anatomic structure in magnetic resonance images (MRI) to which they have not been previously exposed to. The iliolumbar ligament is a good marker for testing learning curves of radiology residents because the ligament is not part of a routine lumbar MRI reporting and has high variability in detection. Four radiologists, three residents without previous training and one mentor, studied standard axial T1- and T2-weighted images of routine lumbar MRI examinations. Radiologists had to define iliolumbar ligament while blinded to each other's findings. Interobserver agreement analyses, namely Cohen and Fleiss κ statistics, were performed for groups of 20 cases to evaluate the self-learning curve of radiology residents. Mean κ values of resident-mentor pairs were 0.431, 0.608, 0.604, 0.826, and 0.963 in the analysis of successive groups (P 0.8). Therefore, a junior radiology resident can obtain enough experience in identifying a rather ambiguous anatomic structure in routine MRI after a brief instruction of a few minutes by a mentor and studying approximately 80 cases by oneself. Implementing this methodology will help radiology educators obtain more concrete ideas on the optimal time and effort required for supported self-directed visual learning processes in resident education. Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.

  17. Mobile learning module improves knowledge of medical shock for forward surgical team members.

    Science.gov (United States)

    Schulman, Carl I; Garcia, George D; Wyckoff, Mary M; Duncan, Robert C; Withum, Kelly F; Graygo, Jill

    2012-11-01

    Acute trauma care is characterized by dynamic situations that require adequate preparation to ensure success for military health professionals. The use of mobile learning in this environment can provide a solution that standardizes education and replaces traditional didactic lectures. A comparative evaluation with a pre-post test design regarding medical shock was delivered via either a didactic lecture or a mobile learning video module to U.S. Army Forward Surgical Team (FST) members. Participants completed a pretest, were randomly assigned to treatment group by FST, and then completed the post-test and scenario assessment. One-hundred and thirteen FST members participated with 53 in the mobile learning group and 60 in the lecture group (control). The percent mean score for the mobile learning group increased from 43.6 to 70 from pretest to post-test, with a scenario mean score of M = 56.2. The percent mean score for the control group increased from 41.5 to 72.5, with a scenario mean score of M = 59.7. The two-way analysis of variance mean score difference was 26.4 for the mobile learning group and 31.0 for the control, F = 2.18, (p = 0.14). Mobile learning modules, coupled with a structured assessment, have the potential to improve educational experiences in civilian and military settings.

  18. Distance learning improves attainment of professional milestones in the early years of surgical training.

    Science.gov (United States)

    Smith, Paula J W; Wigmore, Stephen J; Paisley, Anna; Lamb, Peter; Richards, Jennifer M J; Robson, Andrew J; Revie, Erica; McKeown, Dermot; Dewhurst, David; Garden, O James

    2013-11-01

    To assess the impact of a surgical sciences e-learning programme in supporting the academic development of surgical trainees during their preparation for professional examination. In 2007, a 3-year online part-time Master of Surgical Sciences (MSc) degree programme was launched, utilizing an innovative platform with virtual case scenarios based on common surgical conditions addressed by the curriculum relating to the Membership Examination of the Royal Colleges of Surgeons (MRCS). Multiple-choice questions with feedback and discussion boards facilitated by expert clinical tutors provided formative assessment. Summative assessment comprised written examination at the end of each of the first 2 years (equivalent to MRCS level), culminating in submission of a research dissertation in year 3 toward an MSc. Students' age, gender, and level at entry to the programme were documented. Anonymized student feedback from 2008 to 2012 was examined using online questionnaires, and performance in the MSc programme was compared to MRCS examination outcomes for students who had consented to release of their results. A total of 517 surgical trainees from 40 countries were recruited over the 6-year period, and 116 MSc students have graduated to date. Of 368 students, 279 (76%) were foundation doctors (interns) and had not commenced formal surgical training on enrolling in the MSc programme. However, level at entry did not influence performance (P > 0.05 across all 3 years). Average pass rates since the programme launched, for those students completing all of the required assessments, were 84% ± 11% in year 1, 85% ± 10% in year 2, and 88% ± 7% in year 3 of the MSc programme. MSc students had significantly higher MRCS pass rates than nonenrolled trainees (67% vs 51%, P < 0.01, n = 352). There was a significant correlation between MRCS examination performance and overall performance in the MSc (R = 58%; P < 0.01, n = 37). Of 248 respondents, 202 (81%) considered that the MSc would

  19. Evaluation of a multidisciplinary faculty to support learning in surgical practice.

    Science.gov (United States)

    Brigley, Stephen; Jasper, Melanie

    2010-07-01

    The Theatre Faculty Project was a programme of education seminars, personal study and workplace educational activities for surgeons, operating theatre staff and surgical trainees at a hospital in north-west England. Its aim was to create a multidisciplinary faculty with an understanding of implicit aspects of surgical practice, of how these enter clinical thinking and professional judgement and are used to enhance the learning, teaching and assessment of surgeons. A qualitative evaluation of the faculty project showed improved educational understanding and multidisciplinary awareness among its participants. Refinements of the programme were identified to help those (surgeons in particular) having difficulty conceptually or practically with clinical reflective writing and with portfolio building. However, the support of Trust management at the host hospital will be vital in extending the programme beyond its initial group of volunteers and in integrating the multidisciplinary faculty into its organizational structures.

  20. Learning Curves Among All Patients Undergoing Transcatheter Aortic Valve Implantation in Germany: A Retrospective Observational Study.

    Science.gov (United States)

    Kaier, Klaus; Reinecke, Holger; Schmoor, Claudia; Frankenstein, Lutz; Vach, Werner; Hehn, Philip; Zirlik, Andreas; Bode, Christoph; Zehender, Manfred; Reinöhl, Jochen

    2017-05-15

    Transcatheter aortic valve implantation (TAVI) is a rapidly evolving technique for therapy of aortic stenosis. Previous studies report learning curves with respect to in-hospital mortality and clinical complications. We aim to determine whether observed improvements of in-hospital outcomes after TAVI are the result of improvements in procedures or due to a change in the patient population, and whether improvements differ between the transfemoral (TF) and the transapical (TA) approach. Data was analyzed using risk-adjusted regression analyses in order to track the development of clinical outcomes of all isolated TAVI procedures performed in Germany from 2008 to 2013 (N=32.436) in all German hospitals performing TAVI. Measurements include in-hospital mortality, stroke, bleeding, and mechanical ventilation. Unadjusted mortality rates decrease over time for both TA-TAVI and TF-TAVI. Reductions in mortality were smaller for TA-TAVI than for TF-TAVI. These trends could also be observed for risk-adjusted (standardized) mortality rates, indicating that time trends and differences between TA-TAVI (around 7% in 2013) and TF-TAVI (around 4% in 2013) cannot be explained by changes in the risk factor composition of the patient populations. Bleeding complications decreased for both access routes. Both unadjusted and standardized bleeding rates were substantially higher for TA-TAVI. In addition, TA-TAVI procedures were associated with an increased likelihood of requiring >48h of mechanical ventilation. Observed improvements in TAVI-related in-hospital mortality are not due to a change in patient population. The results indicate the superiority of a TF-first approach. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  1. A Targeted E-Learning Program for Surgical Trainees to Enhance Patient Safety in Preventing Surgical Infection

    Science.gov (United States)

    McHugh, Seamus Mark; Corrigan, Mark; Dimitrov, Borislav; Cowman, Seamus; Tierney, Sean; Humphreys, Hilary; Hill, Arnold

    2010-01-01

    Introduction: Surgical site infection accounts for 20% of all health care-associated infections (HCAIs); however, a program incorporating the education of surgeons has yet to be established across the specialty. Methods: An audit of surgical practice in infection prevention was carried out in Beaumont Hospital from July to November 2009. An…

  2. Is Teaching Simple Surgical Skills Using an Operant Learning Program More Effective Than Teaching by Demonstration?

    Science.gov (United States)

    Levy, I Martin; Pryor, Karen W; McKeon, Theresa R

    2016-04-01

    A surgical procedure is a complex behavior that can be constructed from foundation or component behaviors. Both the component and the composite behaviors built from them are much more likely to recur if it they are reinforced (operant learning). Behaviors in humans have been successfully reinforced using the acoustic stimulus from a mechanical clicker, where the clicker serves as a conditioned reinforcer that communicates in a way that is language- and judgment-free; however, to our knowledge, the use of operant-learning principles has not been formally evaluated for acquisition of surgical skills. Two surgical tasks were taught and compared using two teaching strategies: (1) an operant learning methodology using a conditioned, acoustic reinforcer (a clicker) for positive reinforcement; and (2) a more classical approach using demonstration alone. Our goal was to determine whether a group that is taught a surgical skill using an operant learning procedure would more precisely perform that skill than a group that is taught by demonstration alone. Two specific behaviors, "tying the locking, sliding knot" and "making a low-angle drill hole," were taught to the 2014 Postgraduate Year (PGY)-1 class and first- and second-year medical students, using an operant learning procedure incorporating precise scripts along with acoustic feedback. The control groups, composed of PGY-1 and -2 nonorthopaedic surgical residents and first- and second-year medical students, were taught using demonstration alone. The precision and speed of each behavior was recorded for each individual by a single experienced surgeon, skilled in operant learning. The groups were then compared. The operant learning group achieved better precision tying the locking, sliding knot than did the control group. Twelve of the 12 test group learners tied the knot and precisely performed all six component steps, whereas only four of the 12 control group learners tied the knot and correctly performed all six

  3. Re-learning curve for conventional total knee arthroplasty following 30 consecutive computer-assisted total knee arthroplasties.

    Science.gov (United States)

    Nicholson, Luke T; Trofa, David; Smith, Eric

    2013-01-01

    A learning curve for returning to conventional total knee arthroplasty (TKA) after using computer-assisted (CAS) TKA has not yet been established. In this study, the postoperative mechanical axes of the first 30 consecutive CAS TKAs performed by a single surgeon were compared to his subsequent 120 conventionally performed TKAs. A "re-learning curve" of 30 conventional TKAs was necessary to attain an average postoperative mechanical axis statistically indistinguishable from the average CAS mechanical axis (1.99°). This is a trend of which surgeons should be aware when converting from CAS TKA to conventional TKA. As a secondary goal, the authors identify the first clinical parameter, preoperative deviation from neutral mechanical axis, that may potentially serve as a guide for the selective use of CAS in TKA.

  4. [XPS Greenlight photoselective vaporization for benign prostatic hyperplasia: analysis of the learning curve and contribution of transrectal ultrasound monitoring].

    Science.gov (United States)

    Misrai, V; Faron, M; Elman, B; Bordier, B; Portalez, D; Guillotreau, J

    2013-09-01

    The aim of this study was to analyze the XPS laser learning curve of one single surgeon with no previous experience of PVP and the impact of the use of reel time transrectal ultrasound (TRUS) monitoring. Retrospective analysis of the first 100 patients: group 1 (1st-49th patient without TRUS) and group 2 (50th-100th with TRUS). The learning curve was analyzed through technical variables: vaporization time/intervention time (VT/IT) (%), energy delivered (J)/prostate volume (J/mL) and delivered energy (J/s or Watt), peroperative conversion into monopolar transurethral resection, postoperative complication, duration of catheterization and hospitalization and evolution of International Prostate Symptom Score (IPSS), PSA level, prostate residual volume and Qmax. Relationships between variables were evaluated by analysing the covariance (R 2 software. 14.2). A significant increase in VT/IT (P=0.0001) and the energy delivered per mL prostate (P=0.043) was reported in group 1. The average energy delivered per second was significantly higher in group 2 (P=0.0016). No difference was observed in terms of intra- or postoperative complication and catheterization time. The duration of hospitalization was significantly shorter in group 2 (P=0.03). The use of TRUS was associated with a gain of energy delivered by prostate volume at the end of learning curve (P=0.018). Prostate residual volume was significantly lower in the group 2 (P=0.0004). In our experience, 50 procedures are required to achieve the learning curve of PVP. The use of reel time TRUS would increase the energy delivered by prostate volume. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  5. Enucleation ratio efficacy might be a better predictor to assess learning curve of holmium laser enucleation of the prostate

    Directory of Open Access Journals (Sweden)

    Chang Wook Jeong

    2012-06-01

    Full Text Available PURPOSE: To appraise the evaluation methods for learning curve and to analyze the non-mentor-aided learning curve and early complications following the holmium laser enucleation of the prostate. MATERIALS AND METHODS:One-hundred and forty (n=140 consecutive patients who underwent HoLEP from July 2008 to July 2010 by a single surgeon (SJO were enrolled. Perioperative clinical variables, including enucleation time, morcellation time, enucleation ratio (enucleation weight/transitional zone volume, enucleation efficacy (enucleated weight/enucleation time, enucleation ratio efficacy (enucleation ratio/enucleation time, and early complication rate were analyzed. RESULTS: Mean prostate volume was 62.7 mL (range 21-162 and preoperative International Prostate Symptom Score (IPSS was 19.0 (4-35. Mean enucleation time and morcellation time were 49.9±23.8 (S.D. min and 11.0±9.7 min, respectively. Median duration of postoperative indwelling catheter was 1 (1-7 day and median hospital stay was 1 (1-6 day. There were a total of 31 surgery-related complications in 27 patients (19.3%, and all were manageable. There was an increasing trend of enucleation efficacy in the first 50 cases. However, enucleation efficacy was linearly correlated with the prostate size (correlation coefficients, R=0.701, p<0.001. But, enucleation ratio efficacy could eliminate the confounding effect of the prostate size (R=-0.101, p=0.233. The plateau of enucleation ratio efficacy was reached around the twenty-fifth case. CONCLUSIONS: Our results demonstrated that the operative learning curve plateau is reached after about 25 cases. We propose that a more appropriate parameter for estimating the operative learning curve is enucleation ratio efficacy, rather than enucleation efficacy.

  6. Technical refinement and learning curve for attenuating neurapraxia during robotic-assisted radical prostatectomy to improve sexual function.

    Science.gov (United States)

    Alemozaffar, Mehrdad; Duclos, Antoine; Hevelone, Nathanael D; Lipsitz, Stuart R; Borza, Tudor; Yu, Hua-Yin; Kowalczyk, Keith J; Hu, Jim C

    2012-06-01

    While radical prostatectomy surgeon learning curves have characterized less blood loss, shorter operative times, and fewer positive margins, there is a dearth of studies characterizing learning curves for improving sexual function. Additionally, while learning curve studies often define volume thresholds for improvement, few of these studies demonstrate specific technical modifications that allow reproducibility of improved outcomes. Demonstrate and quantify the learning curve for improving sexual function outcomes based on technical refinements that reduce neurovascular bundle displacement during nerve-sparing robot-assisted radical prostatectomy (RARP). We performed a retrospective study of 400 consecutive RARPs, categorized into groups of 50, performed after elimination of continuous surgeon/assistant neurovascular bundle countertraction. Our approach to RARP has been described previously. A single-console robotic system was used for all cases. Expanded Prostate Cancer Index Composite sexual function was measured within 1 yr of RARP. Linear regression was performed to determine factors influencing the recovery of sexual function. Greater surgeon experience was associated with better 5-mo sexual function (p = 0.007) and a trend for better 12-mo sexual function (p = 0.061), with improvement plateauing after 250-300 cases. Additionally, younger patient age (both pfunction (function. Moreover, trainee robotic console time during nerve sparing was associated with worse 12-mo sexual function (p=0.021), while unilateral nerve sparing/non-nerve sparing was associated with worse 5-mo sexual function (p = 0.009). Limitations include the retrospective single-surgeon design. With greater surgeon experience, attenuating lateral displacement of the neurovascular bundle and resultant neurapraxia improve postoperative sexual function. However, to maximize outcomes, appropriate patient selection must be exercised when allowing trainee nerve-sparing involvement. Copyright © 2012

  7. Short-term outcomes and one surgeon's learning curve for thoracoscopic esophagectomy performed with the patient in the prone position.

    Science.gov (United States)

    Oshikiri, Taro; Yasuda, Takashi; Hasegawa, Hiroshi; Yamamoto, Masashi; Kanaji, Shingo; Yamashita, Kimihiro; Matsuda, Takeru; Sumi, Yasuo; Nakamura, Tetsu; Fujino, Yasuhiro; Tominaga, Masahiro; Suzuki, Satoshi; Kakeji, Yoshihiro

    2017-03-01

    Thoracoscopic esophagectomy with the patient in the prone position (TEP) is now being performed as minimally invasive esophagectomy for esophageal cancer. This study examines the short-term outcomes and the learning curve associated with TEP. One surgeon ("Surgeon A") performed TEP on 100 consecutive patients assigned to three periods based on treatment order. Each group consisted of 33 or 34 patients. The outcomes of the three groups were compared to define the influence of surgeon expertise. Outcomes improved as Surgeon A gained experience in performing this operation, as evidenced by reduced thoracic operative times between periods 1 and 2, and then between periods 2 and 3 (p = 0.0033 and p = 0.0326, respectively); an increased number of retrieved chest nodes between periods 1 and 2 (p = 0.0070); and a decline in recurrent laryngeal nerve (RLN) palsy between periods 2 and 3 (p = 0.0450). Period 2 was the pivotal period for each learning curve. An individual surgeon's learning curve over the course of 100 TEP procedures had three outcomes: a shortened operative time, a higher number of retrieved chest nodes, and a decreased rate of RLN palsy. Approximately 30-60 cases were needed to reach a plateau in the TEP procedure and a reduction in the morbidity rate.

  8. [Prostate cancer boost using high-dose-rate brachytherapy: impact of the learning curve on the dosimetry].

    Science.gov (United States)

    Benhaïm, C; Chand, M-È; Gal, J; Hijazi, H; Gautier, M; Hannoun-Lévi, J-M

    2014-11-01

    To analyse the influence of the learning curve on dosimetric data for high-dose-rate brachytherapy prostate cancer boost. From February 2009 to May 2012, after a first course of external beam radiation therapy (46Gy/23 fractions), 124 patients underwent high-dose-rate brachytherapy boost using Plato™ (Nucletron, an Elekta company, Elekta AB, Stockholm, Sweden). The impact of the learning curve on the dosimetric quality of the prostate implant was assessed. The dosimetric data have been analysed: clinical target volume (CTV), D90 (dose to 90 % of CTV), D100, V100 (part on the CTV receiving 100 % of the dose), V150, V200 and DHI (dose non-homogeneity index). The doses delivered to 0.1, 1 and 2 cm(3) of the rectum and urethra were calculated. During the study period (39 months), a significant reduction of V150 (PD100 (P=0.3). This study confirms that the dosimetric quality of high-dose-rate brachytherapy prostate implant is significantly improved during the learning curve period. Copyright © 2014 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

  9. The effect of surgical and psychological stress on learning and memory function in aged C57BL/6 mice.

    Science.gov (United States)

    Zhang, C; Li, C; Xu, Z; Zhao, S; Li, P; Cao, J; Mi, W

    2016-04-21

    Postoperative cognitive dysfunction (POCD) is an important complication following major surgery and general anesthesia in older patients. However, the etiology of POCD remains largely to be determined. It is unknown how surgical stress and psychological stress affect the postoperative learning and memory function in geriatric patients. We therefore established a pre-clinical model in aged C57BL/6 mice and aimed to investigate the effects of surgical stress and psychological stress on learning and memory function and the possible roles of the protein kinase B/mammalian target of rapamycin (AKT/mTOR) pathway. The surgical stress was induced by abdominal surgery under local anesthesia, and the psychological stress was induced by a communication box. Cognitive functions and markers of the AKT/mTOR pathway were assessed at 1, 3 and 7 days following the stress. The impairments of learning and memory function existed for up to 7 days following surgical stress and surgical stress plus psychological stress, whereas the psychological stress did not affect the cognitive function alone or combined with surgical stress. Analysis of brain tissue revealed a significant involvement of the AKT/mTOR pathway in the impairment of cognition. These data suggested that surgical stress could induce cognitive impairment in aged mice and perioperative psychological stress is not a constitutive factor of POCD. The AKT/mTOR pathway is likely involved as one of the underlying mechanisms of the development of POCD.

  10. Social Media as a Platform for Surgical Learning: Use and Engagement Patterns Among Robotic Surgeons.

    Science.gov (United States)

    Myers, Christopher G; Kudsi, Omar Yusef; Ghaferi, Amir A

    2017-08-29

    : In response to technological advances and growing dispersion of surgical practice around the globe, social media platforms have emerged in recent years as channels for surgeons to share experiences, ask questions, and learn from one another. To better understand surgeons' engagement with these platforms, we analyzed data from a closed-membership Facebook group for robotic surgeons. Our analysis revealed that surgeons posted more frequently on midweek days, and further that text posts received significantly more comments, and significantly fewer "likes," than posts containing links, photos, or videos. We discuss the implications of these use and engagement patterns for the viability of social media platforms as tools for surgeons to learn vicariously from their peers' experiences and expertise.

  11. Self-directed Learning in Otolaryngology Residents' Preparation for Surgical Cases.

    Science.gov (United States)

    Jabbour, Jad; Bakeman, Anna; Robey, Thomas; Jabbour, Noel

    2017-04-01

    To characterize the nature of surgical preparation among otolaryngology residents nationwide, determine the self-rated effectiveness and efficiency of case preparation practices, and identify potential means for educational improvement. A survey examining the study objectives was developed and distributed to otolaryngology residents nationwide. Survey response data were submitted to descriptive analysis and comparative analyses between junior and senior residents. Literature regarding case preparation among otolaryngology residents was reviewed. Among 108 resident respondents, the most commonly used resources included textbooks (86.1%), surgical education websites (74.1%), and surgical atlases (66.7%). Time was the primary limitation (cited by 84.3%) and convenience the predominant factor influencing resource selection (92.5%). On a 5-point Likert scale, mean scores regarding effectiveness and efficiency of case preparation were 3.53 ± 0.68 and 3.19 ± 0.88, respectively. Senior residents compared to junior residents were more likely to rate their preparation as effective (3.75 ± 0.54 vs 3.40 ± 0.72, P = .008) and efficient (3.45 ± 0.85 vs 3.03 ± 0.86, P = .02). Otolaryngology residents do not consistently rate their case preparation as effective or efficient. While there appears to be progress in self-directed learning throughout residency, room for improvement remains, with potential avenues for such improvement explored here.

  12. Service learning: Priority 4 Paws mobile surgical service for shelter animals.

    Science.gov (United States)

    Freeman, Lynetta J; Ferguson, Nancy; Litster, Annette; Arighi, Mimi

    2013-01-01

    The increasing attention given to competencies needed to enter the workforce has revealed a need for veterinary students to gain more experience in performing small-animal elective surgery before graduation. In addition, guidelines for standards of care for shelter animals recommend that all dogs and cats should be spayed or neutered before adoption. Teaching surgical skills while serving the needs of local animal shelters represents an ideal service-learning opportunity. Following a pilot study and the benchmarking of other programs, an elective course in shelter medicine and surgery was created at Purdue University College of Veterinary Medicine (PVM) to allow senior DVM students an opportunity to spend 2 weeks on a mobile surgery unit (Priority 4 Paws) and 1 week at an animal shelter. With financial assistance from sponsors and donors, PVM purchased and equipped a mobile surgery unit, hired a full-time veterinarian and a registered veterinary technician, and established relationships with 12 animal shelters. From July 30, 2012, to March 22, 2013, 1,941 spays and neuters were performed with excellent postsurgical outcomes while training 33 veterinary students on rotation and 26 veterinary technician students. The program was well accepted by both students and the shelters being served. The Priority 4 Paws program is an example of an integrated, community-based service-learning opportunity that not only helps to improve the surgical skills of veterinary students but also helps to meet an identified community need.

  13. Learning curve analyses in neurodevelopmental disorders: are children with autism spectrum disorder truly visual learners?

    Science.gov (United States)

    Erdődi, Lászlό; Lajiness-O'Neill, Renée; Schmitt, Thomas A

    2013-04-01

    Visual and auditory verbal learning using a selective reminding format was studied in a mixed clinical sample of children with autism spectrum disorder (ASD) (n = 42), attention-deficit hyperactivity disorder (n = 83), velocardiofacial syndrome (n = 17) and neurotypicals (n = 38) using the Test of Memory and Learning to (1) more thoroughly characterize and examine the integrity of learning and memory processes, (2) to better understand the mechanisms of learning impairment, and (3) to inform instructional practices in ASD. Contrary to expectations, children with ASD demonstrated a relative weakness in the rate of acquisition of visual in contrast to verbal learning compared to neurotypicals. They also showed a complex pattern of consolidation. Overall, between-group differences were more likely to emerge during the visual learning task, suggesting that it may be more sensitive for detecting neurodevelopmental differences. The heuristic value of assessing memory and learning across multiple trials and comparing performance during immediate and delayed recall is discussed.

  14. A variation reduction allocation model for quality improvement to minimize investment and quality costs by considering suppliers’ learning curve

    Science.gov (United States)

    Rosyidi, C. N.; Jauhari, WA; Suhardi, B.; Hamada, K.

    2016-02-01

    Quality improvement must be performed in a company to maintain its product competitiveness in the market. The goal of such improvement is to increase the customer satisfaction and the profitability of the company. In current practice, a company needs several suppliers to provide the components in assembly process of a final product. Hence quality improvement of the final product must involve the suppliers. In this paper, an optimization model to allocate the variance reduction is developed. Variation reduction is an important term in quality improvement for both manufacturer and suppliers. To improve suppliers’ components quality, the manufacturer must invest an amount of their financial resources in learning process of the suppliers. The objective function of the model is to minimize the total cost consists of investment cost, and quality costs for both internal and external quality costs. The Learning curve will determine how the employee of the suppliers will respond to the learning processes in reducing the variance of the component.

  15. Generating a learning curve for pediatric caudal epidural blocks: an empirical evaluation of technical skills in novice and experienced anesthetists.

    Science.gov (United States)

    Schuepfer, G; Konrad, C; Schmeck, J; Poortmans, G; Staffelbach, B; Jöhr, M

    2000-01-01

    Learning curves for anesthesia procedures in adult patients have been determined, but no data are available on procedures in pediatric anesthesia. The aim of this study was to assess the number of caudal blocks needed to guarantee a high success rate in performing caudal epidural analgesia in children. At a teaching hospital, the technical skills of 7 residents in anesthesiology who performed caudal blocks were evaluated during 4 months using a standardized self-evaluation questionnaire. At the start of the study period, the residents had no prior experience in pediatric anesthesia or in performing caudal epidural blocks. All residents entered the pediatric rotation after a minimum of 1 year of training in adult general and regional anesthesia. The blocks were rated using a binary score. For comparison, the success rates of 8 experienced staff anesthesiologists were collected during the same period using the same self-evaluation questionnaire. Statistical analyses were performed by generating individual and institutional learning curves using the pooled data. The learning curves were calculated with the aid of a least-square fit model and 95% confidence intervals were estimated by a Monte Carlo procedure with a bootstrap technique. The success rate of residents was 80% after 32 procedures (95% confidence interval of 0.59 to 1.00). The pooled success rate of the staff anesthesiologists was 0.73 (mean) with a standard deviation of 0.45, which was not statistically different from the success rate of the residents. High success rates in performing caudal anesthesia in pediatric patients can be acquired after a limited number of cases. Success rates of residents learning this procedure are comparable to the results of staff anesthesiologists.

  16. The learning curve of the three-port two-instrument complete thoracoscopic lobectomy for lung cancer—A feasible technique worthy of popularization

    Directory of Open Access Journals (Sweden)

    Yu-Jen Cheng

    2015-07-01

    Conclusion: Three-port complete thoracoscopic lobectomy with the two-instrument technique is feasible for lung cancer treatment. The length of the learning curve consisted of 28 cases. This TPTI technique should be popularized.

  17. Analysis of the learning curve for pre-cut corneal specimens in preparation for lamellar transplantation: a prospective, single-centre, consecutive case series prepared at the Lions New South Wales Eye Bank.

    Science.gov (United States)

    Martin, Aifric Isabel; Devasahayam, Rajnesh; Hodge, Christopher; Cooper, Simon; Sutton, Gerard L

    2017-03-06

    This study is the first paper to establish a learning curve by a single technician. Preparation of pre-cut corneal endothelial grafts commenced at Lions New South Wales Eye Bank in December 2014. The primary objective of this study was to review the safety and reliability of the preparation method during the first year of production. This is a hospital-based, prospective case series. There were 234 consecutive donor corneal lenticules. Donor lenticules were prepared by a single operator using a linear cutting microkeratome. Immediately prior to cutting, central corneal thickness values were recorded. Measurements of the corneal bed were taken immediately following lenticule preparation. Outcomes were separated by blade sizes, and intended thickness was compared to actual thickness for each setting. Early specimens were compared to later ones to assess for a learning curve within the technique. The main parameter measured is the mean difference from intended lamellar cut thickness. The mean final cut thickness was 122.36 ± 20.35 μm, and the mean difference from intended cut was 30.17 ± 37.45 μm. No significant difference was found between results achieved with early specimens versus those achieved with later specimens (P = 0.425). Thin, reproducible endothelial grafts can routinely be produced by trained technicians at their respective eye banks without significant concerns for an extended learning curve. This service can reduce perioperative surgical complexity, required surgical paraphernalia and theatre times. The consistent preparation of single-pass, ultrathin pre-cut corneas may have additional advantages for surgeons seeking to introduce lamellar techniques. © 2017 Royal Australian and New Zealand College of Ophthalmologists.

  18. Big Data and Machine Learning in Plastic Surgery: A New Frontier in Surgical Innovation.

    Science.gov (United States)

    Kanevsky, Jonathan; Corban, Jason; Gaster, Richard; Kanevsky, Ari; Lin, Samuel; Gilardino, Mirko

    2016-05-01

    Medical decision-making is increasingly based on quantifiable data. From the moment patients come into contact with the health care system, their entire medical history is recorded electronically. Whether a patient is in the operating room or on the hospital ward, technological advancement has facilitated the expedient and reliable measurement of clinically relevant health metrics, all in an effort to guide care and ensure the best possible clinical outcomes. However, as the volume and complexity of biomedical data grow, it becomes challenging to effectively process "big data" using conventional techniques. Physicians and scientists must be prepared to look beyond classic methods of data processing to extract clinically relevant information. The purpose of this article is to introduce the modern plastic surgeon to machine learning and computational interpretation of large data sets. What is machine learning? Machine learning, a subfield of artificial intelligence, can address clinically relevant problems in several domains of plastic surgery, including burn surgery; microsurgery; and craniofacial, peripheral nerve, and aesthetic surgery. This article provides a brief introduction to current research and suggests future projects that will allow plastic surgeons to explore this new frontier of surgical science.

  19. 排球运动技能学习曲线的相关性研究%The Related Investigation about Learning Curve of Volleyball Moving Skills

    Institute of Scientific and Technical Information of China (English)

    宋玉婷

    2012-01-01

    采用文献资料、观察记录、图表分析等研究方法,对排球技能的学习曲线做了系统的探究。结果表明:排球运动技能学习曲线的类型主要有线形学习曲线、先快后慢的负加速形学习曲线、先慢后快的正加速形学习曲线、S形学习曲线、高原平台学习曲线;只要正确认识排球运动技能学习曲线就会对排球的技能学习有规律性认识,加速排球运动技能的形成。%Systematic exploration about learning curves of volleyball skins were conducted according to research techniques of consulting reported literature, observing and recording, and diagram analysis, etc.. Results achieved by this research were given by the following: linear learning curve, negative accelerating learning curve moving fast first and then slowing down, positive accelerating learning curve moving slowly and then speeding up, S form learning curve, and plateau platform learning curve were all included in main learning curves of volleyball moving skills. The study of volleyball skills could be eognized regularly as long as learning curves of volleyball skills were understood correctly, speeding up the formation of volleyball moving skills.

  20. Surgery for stage 5 retinopathy of prematurity: The learning curve and evolving technique

    Directory of Open Access Journals (Sweden)

    Gopal Lingam

    2000-01-01

    Full Text Available Purpose: To describe our experience with management of eyes with stage 5 retinopathy of prematurity (ROP Methods: Closed vitreoretinal surgery was done on 96 eyes of patients with stage 5 ROP. Lens was sacrificed in all but one eye. Surgery involved an attempt to clear all preretinal tissue and open the peripheral trough all round. In most instances bimanual surgery under viscoelastic was performed. Results: At last follow up, anatomical success (defined as attached posterior pole was achieved in 22.5% cases. Significant postoperative problems included reproliferation and secondary glaucoma. Only two infants obtained mobile vision. Conclusion: Late identification of disease, lack of prior treatment such as laser or cryo, and higher incidence of narrow-narrow funnel configuration were responsible for the poor surgical results noted in this series. The poor surgical and functional results reemphasise the need for prompt screening and management of infants at risk.

  1. Learning Curve in a Western Training Center of the Circumferential En Bloc Esophageal Endoscopic Submucosal Dissection in an In Vivo Animal Model

    Science.gov (United States)

    Tanimoto, Miguel A.; Torres-Villalobos, Gonzalo; Fujita, Rikiya; Santillan-Doherty, Patricio; Albores-Saavedra, Jorge; Chable-Montero, Fredy; Martin-del-Campo, Luis A.; Vasquez, Lucia; Bravo-Reyna, Carlos; Villanueva, Octavio; Villalobos, Jose J.; Uribe, Misael; Valdovinos, Miguel A.

    2011-01-01

    Aim. Evaluate the feasibility to overcome the learning curve in a western training center of the en bloc circumferential esophageal (ECE-) ESD in an in vivo animal model. Methods. ECE-ESD was performed on ten canine models under general anesthesia on artificial lesions at the esophagus marked with coagulation points. After the ESD each canine model was euthanized and surgical resection of the esophagus and stomach was carried out according to “the Principles of Humane Experimental Technique, Russel and Burch.” The specimen was fixed with needles on cork submerged in formalin with the esophagus and stomach then delivered to the pathology department to be analyzed. Results. ECE-ESD was completed without complications in the last 3/10 animal models. Mean duration for the procedures was 192 ± 35 minutes (range 140–235 minutes). All the procedures were done at the animal lab surgery room with cardio pulmonary monitoring and artificial ventilation by staff surgery members and a staff member of the Gastroenterology department trained during 1999–2001 at the Fujigaoka hospital of the Showa U. in Yokohama, Japan, length (range 15–18 mm) and 51 ± 6.99 width (range 40–60 mm). Conclusion. ECE-ESD training is feasible in canine models for postgraduate endoscopy fellows. PMID:21976950

  2. Learning Curve in a Western Training Center of the Circumferential En Bloc Esophageal Endoscopic Submucosal Dissection in an In Vivo Animal Model

    Directory of Open Access Journals (Sweden)

    Miguel A. Tanimoto

    2011-01-01

    Full Text Available Aim. Evaluate the feasibility to overcome the learning curve in a western training center of the en bloc circumferential esophageal (ECE- ESD in an in vivo animal model. Methods. ECE-ESD was performed on ten canine models under general anesthesia on artificial lesions at the esophagus marked with coagulation points. After the ESD each canine model was euthanized and surgical resection of the esophagus and stomach was carried out according to “the Principles of Humane Experimental Technique, Russel and Burch.” The specimen was fixed with needles on cork submerged in formalin with the esophagus and stomach then delivered to the pathology department to be analyzed. Results. ECE-ESD was completed without complications in the last 3/10 animal models. Mean duration for the procedures was 192±35 minutes (range 140–235 minutes. All the procedures were done at the animal lab surgery room with cardio pulmonary monitoring and artificial ventilation by staff surgery members and a staff member of the Gastroenterology department trained during 1999–2001 at the Fujigaoka hospital of the Showa U. in Yokohama, Japan, length (range 15–18 mm and 51±6.99 width (range 40–60 mm. Conclusion. ECE-ESD training is feasible in canine models for postgraduate endoscopy fellows.

  3. Surgical training and the European Working Time Directive: The role of informal workplace learning.

    Science.gov (United States)

    Giles, James A

    2010-01-01

    The introduction of European Working Time Directive, limiting doctors' working hours to 48 per week, has caused recent controversy within the profession. The Royal College of Surgeons of England in particular has been one of the loudest critics of the legislation. One of the main concerns is regarding the negative impact on training hours for those embarking on surgical careers. Simulation technology has been suggested as a method to overcome this reduction in hospital training hours, and research suggests that this is a good substitute for operative training in a theatre. However, modern educational theory emphasises the power of informal workplace learning in postgraduate education, and the essential role of experience in training future surgeons.

  4. Electronic learning can facilitate student performance in undergraduate surgical education: a prospective observational study

    Directory of Open Access Journals (Sweden)

    Gorey Thomas

    2005-06-01

    Full Text Available Abstract Background Our institution recently introduced a novel internet accessible computer aided learning (iCAL programme to complement existing surgical undergraduate teaching methods. On graduation of the first full cycle of undergraduate students to whom this resource was available we assessed the utility of this new teaching facility. Method The computer programme prospectively records usage of the system on an individual user basis. We evaluated the utilisation of the web-based programme and its impact on class ranking changes from an entry-test evaluation to an exit examination in surgery. Results 74.4% of students were able to access iCAL from off-campus internet access. The majority of iCAL usage (64.6% took place during working hours (08:00–18:00 with little usage on the weekend (21.1%. Working hours usage was positively associated with improvement in class rank (P = 0.025, n = 148 but out-of hours usage was not (P = 0.306. Usage during weekdays was associated with improved rank (P = 0.04, whereas weekend usage was not (P = 0.504. There were no significant differences in usage between genders (P = 0.3. Usage of the iCAL system was positively correlated with improvement in class rank from the entry to the exit examination (P = 0.046. Students with lower ranks on entry examination, were found to use the computer system more frequently (P = 0.01. Conclusion Electronic learning complements traditional teaching methods in undergraduate surgical teaching. Its is more frequently used by students achieving lower class ranking with traditional teaching methods, and this usage is associated with improvements in class ranking.

  5. Enhancing medical-surgical nursing practice: using practice tests and clinical examples to promote active learning and program evaluation.

    Science.gov (United States)

    DuHamel, Martha B; Hirnle, Constance; Karvonen, Colleen; Sayre, Cindy; Wyant, Sheryl; Colobong Smith, Nancy; Keener, Sheila; Barrett, Shannon; Whitney, Joanne D

    2011-10-01

    In a 14-week medical-surgical nursing review course, two teaching strategies are used to promote active learning and assess the transfer of knowledge to nursing practice. Practice tests and clinical examples provide opportunities for participants to engage in self-assessment and reflective learning and enhance their nursing knowledge, skills, and practice. These strategies also contribute to program evaluation and are adaptable to a variety of course formats, including traditional classroom, web conference, and online self-study.

  6. The learning curve for laparoscopic colectomy in colorectal cancer at a new regional hospital

    Directory of Open Access Journals (Sweden)

    Kuei-Yen Tsai

    2016-01-01

    Conclusion: Laparoscopic colectomy for colorectal cancer in a new regional hospital is feasible and safe. It does not need additional time for learning. Laparoscopic sigmoidectomy can be considered as the initial surgery for a trainee.

  7. Short-radius horizontal well re-entry learning curve: prize, cost and operational experience

    Energy Technology Data Exchange (ETDEWEB)

    Boote, K. [Ocelot Energy Inc., Calgary, AB (Canada); MacDonald, R. [Lauron Engineering Ltd, Calgary, AB (Canada)

    1997-12-01

    Six mature vertical wells in Alberta belonging to Ocelot Energy Inc., were reentered and drilled horizontally. Experiences gained, the modifications made to the drilling program and the rewards in the form of incremental oil, were discussed. Details of pre- and post-performance, operational experiences with exiting the casing, building the curve, overbalance versus underbalanced drilling, motors, directional equipment, setting liners, remedial workovers and the cost of the operation were part of the discussion.

  8. Ensemble Learning Method for Outlier Detection and its Application to Astronomical Light Curves

    Science.gov (United States)

    Nun, Isadora; Protopapas, Pavlos; Sim, Brandon; Chen, Wesley

    2016-09-01

    Outlier detection is necessary for automated data analysis, with specific applications spanning almost every domain from financial markets to epidemiology to fraud detection. We introduce a novel mixture of the experts outlier detection model, which uses a dynamically trained, weighted network of five distinct outlier detection methods. After dimensionality reduction, individual outlier detection methods score each data point for “outlierness” in this new feature space. Our model then uses dynamically trained parameters to weigh the scores of each method, allowing for a finalized outlier score. We find that the mixture of experts model performs, on average, better than any single expert model in identifying both artificially and manually picked outliers. This mixture model is applied to a data set of astronomical light curves, after dimensionality reduction via time series feature extraction. Our model was tested using three fields from the MACHO catalog and generated a list of anomalous candidates. We confirm that the outliers detected using this method belong to rare classes, like Novae, He-burning, and red giant stars; other outlier light curves identified have no available information associated with them. To elucidate their nature, we created a website containing the light-curve data and information about these objects. Users can attempt to classify the light curves, give conjectures about their identities, and sign up for follow up messages about the progress made on identifying these objects. This user submitted data can be used further train of our mixture of experts model. Our code is publicly available to all who are interested.

  9. Learning curve and interobserver agreement of confocal laser endomicroscopy for detecting precancerous or early-stage esophageal squamous cancer.

    Directory of Open Access Journals (Sweden)

    Jing Liu

    Full Text Available Confocal laser endomicroscopy (CLE can provide in vivo subcellular resolution images of esophageal lesions. However, the learning curve in interpreting CLE images of precancerous or early-stage esophageal squamous cancer is unknown. The goal of this study is to evaluate the diagnostic accuracy and inter-observer agreement for differentiating esophageal lesions in CLE images among experienced and inexperienced observers and to assess the learning curve.After a short training, 8 experienced and 14 inexperienced endoscopists evaluated in sequence 4 sets of high-quality CLE images. Their diagnoses were corrected and discussed after each set. For each image, the diagnostic results, confidence in diagnosis, quality and time to evaluate were recorded.Overall, diagnostic accuracy was greater for the second, third, fourth set of images as compared with the initial set (odds ratio [OR] 2.01, 95% CI 1.22-3.31; 7.95, 3.74-16.87; and 6.45, 3.14-13.27, respectively, with no difference between the third and fourth sets in accuracy (p = 0.67. Previous experience affected the diagnostic accuracy only in the first set of images (OR 3.70, 1.87-7.29, p<0.001. Inter-observer agreement was higher for experienced than inexperienced endoscopists (0.732 vs. 0.666, p<0.01.CLE is a promising technology that can be quickly learned after a short training period; previous experience is associated with diagnostic accuracy only at the initial stage of learning.

  10. Evaluation of the Plug-in Hybrid Electric Vehicle Considering Learning Curve on Battery and Power Generation Best Mix

    Science.gov (United States)

    Shinoda, Yukio; Tanaka, Hideo; Akisawa, Atsushi; Kashiwagi, Takao

    Plug-in Hybrid Electric Vehicle (PHEV) is one of the technologies to reduce amount of CO2 emissions in transport section. This paper presents one of the scenarios that shows how widely used the PHEVs will be in the future. And this paper also presents how amount of CO2 will be reduced by the introduction of PHEVs, and whether there are any serious effects on power supply system in those scenarios. PHEV can run with both gasoline and electricity. Therefore we evaluate CO2 emissions not only from gasoline consumption but also from electricity consumption. To consider a distribution of daily-trip-distance is important for evaluating the economical merit and CO2 emissions by introducing of PHEV. Also, the battery cost in the future is very important for making a PHEV's growth scenario. The growth of the number of PHEV makes battery cost lower. Then, we formulate the total model that combines passenger car sector and power supply sector with considering a distribution of daily-trip-distance and Learning Curve on battery costs. We use the iteration method to consider a Learning Curve that is non- linear. Therefore we set battery cost only in the first year of the simulation. Battery costs in the later year are calculated in the model. We focus on the 25-year time frame from 2010 in Japan, with divided in 5 terms (1st∼5th). And that model selects the most economical composition of car type and power sources.

  11. Development and validation of a surgical training simulator with haptic feedback for learning bone-sawing skill.

    Science.gov (United States)

    Lin, Yanping; Wang, Xudong; Wu, Fule; Chen, Xiaojun; Wang, Chengtao; Shen, Guofang

    2014-04-01

    Bone sawing or cutting is widely used for bone removal processes in bone surgery. It is an essential skill that surgeons should execute with a high level of experience and sensitive force perception. Surgical training simulators, with virtual and haptic feedback functions, can offer a safe, repeatable and cost-effective alternative to traditional surgeries. In this research, we developed a surgical training simulator with virtual and haptic force feedback for maxillofacial surgery, and we validated the effects on the learning of bone-sawing skills through empirical evaluation. Omega.6 from Force Dimension was employed as the haptic device, and Display300 from SenseGraphices was used as the 3D stereo display. The voxel-based model was constructed using computed tomography (CT) images, and the virtual tools were built through reverse engineering. The multi-point collision detection method was applied for haptic rendering to test the 3D relationship between the virtual tool and the bone voxels. Bone-sawing procedures in maxillofacial surgery were simulated with a virtual environment and real-time haptic feedback. A total of 25 participants (16 novices and 9 experienced surgeons) were included in 2 groups to perform the bone-sawing simulation for assessing the construct validity. Each of the participants completed the same bone-sawing procedure at the predefined maxillary region six times. For each trial, the sawing operative time, the maximal acceleration, and the percentage of the haptic force exceeding the threshold were recorded and analysed to evaluate the validity. After six trials, all of the participants scored the simulator in terms of safe force learning, stable hand control and overall performance to confirm the face validity. Moreover, 10 novices in 2 groups indentified the transfer validity on rapid prototype skull models by comparing the operative time and the maximal acceleration. The analysed results of construct validity showed that the two groups

  12. The development of an interactive game-based tool for learning surgical management algorithms via computer.

    Science.gov (United States)

    Mann, Barry D; Eidelson, Benjamin M; Fukuchi, Steven G; Nissman, Steven A; Robertson, Scott; Jardines, Lori

    2002-03-01

    We have previously demonstrated the potential efficacy of a computer-assisted board game as a tool for medical education. The next logical step was to transfer the entire game on to the computer, thus increasing accessibility to students and allowing for a richer and more accurate simulation of patient scenarios. First, a general game model was developed using Microsoft Visual Basic. A breast module was then created using 3-D models, radiographs, and pathology and cytology images. The game was further improved by the addition of an animated facilitator, who directs the players via gestures and speech. Thirty-three students played the breast module in a variety of team configurations. After playing the game, the students completed surveys regarding its value as both an educational tool and as a form of entertainment. 10-question tests were also administered before and after playing the game, as a preliminary investigation into its impact on student learning. After playing the game, mean test scores increased from 6.43 (SEM +/- 0.30) to 7.14 (SEM +/- 0.30; P = 0.006). The results of the five-question survey were extremely positive. Students generally agreed that the game concept has value in increasing general knowledge regarding the subject matter of breast disease and that the idea of following simultaneously the work-up of numerous patients with similar problems is a helpful way to learn a work-up algorithm. Postgame surveys demonstrate the efficacy of our computer game model as a tool for surgical education. The game is an example of problem based learning because it provides students with an initial set of problems and requires them to collect information and reason on their own in order to solve the problems. Individual game modules can be developed to cover material from different diagnostic areas.

  13. Surgical resident learning styles: faculty and resident accuracy at identification of preferences and impact on ABSITE scores.

    Science.gov (United States)

    Kim, Roger H; Gilbert, Timothy; Ristig, Kyle; Chu, Quyen D

    2013-09-01

    As a consequence of surgical resident duty hour restrictions, there is a need for faculty to utilize novel teaching methods to convey information in a more efficient manner. The current paradigm of surgical training, which has not changed significantly since the time of Halsted, assumes that all residents assimilate information in a similar fashion. However, recent data has shown that learners have preferences for the ways in which they receive and process information. The VARK model categorizes learners as visual (V), aural (A), read/write (R), and kinesthetic (K). The VARK learning style preferences of surgical residents have not been previously evaluated. In this study, the preferred learning styles of general surgery residents were determined, along with faculty and resident perception of resident learning styles. In addition, we hypothesized that American Board of Surgery In-Training Exam (ABSITE) scores are associated with preference for a read/write (R) learning style. The Fleming VARK learning styles inventory was administered to all general surgery residents at a university hospital-based program. Responses on the inventory were scored to determine the preferred learning style for each resident. Faculty members were surveyed to determine their accuracy in identifying the preferred learning style of each resident. All residents were also surveyed to determine their accuracy in identifying their peers' VARK preferences. Resident ABSITE scores were examined for association with preferred learning styles. Twenty-nine residents completed the inventory. Most (18 of 29, 62%) had a multimodal preference, although more than a third (11 of 29, 38%) demonstrated a single-modality preference. Seventy-six percent of all residents (22 of 29) had some degree of kinesthetic (K) learning, while under 50% (14 of 29) were aural (A) learners. Although not significant, dominant (R) learners had the highest mean ABSITE scores. Faculty identified residents' learning styles

  14. Analysis of learning curves in the on-the-job training of air traffic controllers

    NARCIS (Netherlands)

    Oprins, E.A.P.B.; Bruggraaff, E.; Roe, R.

    2011-01-01

    This chapter describes a competence-based assessment system, called CBAS, for air traffic control (ATC) simulator and on-the-job training (OJT), developed at Air Traffic Control The Netherlands (LVNL). In contrast with simulator training, learning processes in OJT are difficult to assess, because th

  15. An evaluation of the success of a surgical resident learning portfolio.

    Science.gov (United States)

    Webb, Travis P; Merkley, Taylor R

    2012-01-01

    Learning portfolios have gained modest acceptance in graduate medical education because of challenges related to user satisfaction, time and resource commitment, and quality assessment. In 2001, the Department of Surgery implemented the Surgical Learning and Instructional Portfolio (SLIP) to help residents develop a case-based portfolio demonstrating practice-based learning. In 2008, the format was changed to a Web-based platform with open viewing of portfolios for all learners. This study was performed to evaluate the SLIP program using resident and faculty perspectives in the domains of satisfaction, compliance, and educational value. Likert scale surveys were distributed to residents to assess satisfaction. Using a semistructured format with subsequent qualitative analysis of the meeting transcript, a focus group discussion was held with the SLIP director, SLIP facilitator, and program coordinator. An analysis of the program compliance was performed by review of SLIP entry dates. Finally, the quality of the SLIP entries (n = 420) was analyzed in a blinded manner using a locally developed standardized SLIP assessment tool. Data analysis was performed using Pearson's correlation and Cronbach's alpha. Residents were satisfied with the program and felt the Web-based format promoted self-reflection. They perceived that time spent was appropriate. Residents also believed they gained medical knowledge of their own specific entry topics but did not learn routinely from others' entries. Faculty asserted that the Web-based platform eased the administrative burden but did not necessarily alter the quality of the SLIP entries. Compliance with the assignment was 100%. SLIP entry analysis demonstrated the reflection and understanding of the topics chosen. However, the overall quality assessment of entries was hindered by suboptimal interrater reliability (inter-rater reliability (IR) = 0.636). The SLIP program allows residents to demonstrate practice-based learning and

  16. Is the learning curve for video-assisted thoracoscopic lobectomy affected by prior experience in open lobectomy?

    Science.gov (United States)

    Okyere, Sharon; Attia, Rizwan; Toufektzian, Levon; Routledge, Tom

    2015-07-01

    A best evidence topic was written according to a structured protocol. The question addressed is the learning curve for video-assisted thoracoscopic (VATS) lobectomy affected by prior experience in open lobectomy? Two hundred and two studies were identified of which seven presented the best evidence on the topic. The authors, date, journal, country of publication, study type, participating surgeon and relevant outcomes are tabulated. The studies presented discuss the learning experiences of surgeons with a range of proficiency in open lobectomy in performing VATS lobectomy. Four of the studies made direct comparisons between the outcomes achieved by trainees and fully qualified surgeons. Trainees performed a total of 154 VATS lobectomies and the consultants performed 714. The reported number of open lobectomies performed by trainees ranged 14-50. In one study, a qualified surgeon who had performed 100 open lobectomies achieved a statistically significant progression in his learning curve and was able to safely perform VATS lobectomies after 6 months. A trainee who had performed only 14 open lobectomies achieved a similar blood loss to his experienced supervisors (P = 0.79). Two trainee surgeons who had each performed at least 20 open lobectomies achieved similar mean intraoperative blood loss (P = 0.2) and complication rate (P = 0.4) to their experienced consultant when performing VATS lobectomy. Average duration of chest drainage was similar between consultant and trainee groups (P = 0.34) and was improved in favour of trainees in one group (P experience in open lobectomy can achieve good outcomes in VATS lobectomy comparable with their more experienced seniors. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  17. Beliefs and values about intra-operative teaching and learning: a case study of surgical teachers and trainees.

    Science.gov (United States)

    Ong, Caroline C P; Dodds, Agnes; Nestel, Debra

    2016-08-01

    Surgeons require advanced psychomotor skills, critical decision-making and teamwork skills. Much of surgical skills training involve progressive trainee participation in supervised operations where case variability, operating team interaction and environment affect learning, while surgical teachers face the key challenge of ensuring patient safety. Using a theoretical framework of situated learning including cognitive apprenticeship, we explored teachers' and trainees' beliefs and values about intra-operative training and reasons for any differences. A qualitative case study method was used where five teacher-trainee pairs participating in an observed teaching operation were separately interviewed about the same operation. Thematic analysis of transcribed interviews and observations was performed with iterative refinement and a reflexive approach was adopted throughout the study. We found that in all cases, teachers and trainees had shared recognition of learning about technical skills whereas they differed in three cases regarding non-technical skills such as surgical reasoning and team management. Factors contributing to teacher and trainee satisfaction with the process were successful trainee completion of operation without need for surgeon take-over, a positive learning environment and learning new things. Teaching-learning behaviours observed and discussed were modeling, coaching and scaffolding, while exploration, reflection and articulation were less common. Our study reveals differing teacher and trainee perspectives of some aspects of intra-operative training and surfaces new reasons other than amount of feedback and autonomy given. Factors contributing to different perspectives include teacher and trainee abilities, values and situational influences. Targeted teaching-learning strategies could enhance intra-operative learning.

  18. Modelling ramp-up curves to reflect learning: improving capacity planning in secondary pharmaceutical production

    DEFF Research Database (Denmark)

    Hansen, Klaus Reinholdt Nyhuus; Grunow, Martin

    2015-01-01

    are overestimated. We develop a new method, which captures ramp-up as a function of the cumulative production volume to better reflect the experience gained while producing the new product. The use of the more accurate and computationally effective approach is demonstrated for the case of secondary pharmaceutical...... production. Due to its regulatory framework, this industry cannot fully exploit available capacities during ramp-up. We develop a capacity planning model for a new pharmaceutical drug, which determines the number and location of new production lines and the build-up of inventory such that product...... availability at market launch is ensured. Our MILP model is applied to a real industry case study using three empirically observed ramp-up curves to demonstrate its value as decision support tool. We demonstrate the superiority of our volume-dependent method over the traditional time-dependent ramp...

  19. Differences in Learning Style Preferences, Environmental Press Perceptions and Job Satisfaction between Surgical Intensive Care and General Surgical Unit Nurses

    Science.gov (United States)

    1991-01-01

    well-defined theoretical basis (Bonham, 1988; Kirby, 1979). Although Kolb (1984) incorporated the works of Kurt Lewin , Jean Piaget and Carl Jung, John...styles influence how individuals assimilate environmental demands. Kolb’s (1984) Experiential Learning Theory, whose roots are traced to John Dewey, Kurt ... Lewin , and Jean Piaget, provides a methodological framework to understand and strengthen the relationshios between education, personal development

  20. Assessment of performance measures and learning curves for use of a virtual-reality ultrasound simulator in transvaginal ultrasound examination

    DEFF Research Database (Denmark)

    Madsen, M E; Konge, L; Nørgaard, L N

    2014-01-01

    OBJECTIVE: To assess the validity and reliability of performance measures, develop credible performance standards and explore learning curves for a virtual-reality simulator designed for transvaginal gynecological ultrasound examination. METHODS: A group of 16 ultrasound novices, along with a group......-6), corresponding to an average of 219 min (range, 150-251 min) of training. The test/retest reliability was high, with an intraclass correlation coefficient of 0.93. CONCLUSIONS: Competence in the performance of gynecological ultrasound examination can be assessed in a valid and reliable way using virtual-reality...... of 12 obstetrics/gynecology (Ob/Gyn) consultants, were included in this experimental study. The first two performances of the two groups on seven selected modules on a high-fidelity ultrasound simulator were used to identify valid and reliable metrics. Performance standards were determined and novices...

  1. A statistical physics approach to learning curves for the inverse Ising problem

    Science.gov (United States)

    Bachschmid-Romano, Ludovica; Opper, Manfred

    2017-06-01

    Using methods of statistical physics, we analyse the error of learning couplings in large Ising models from independent data (the inverse Ising problem). We concentrate on learning based on local cost functions, such as the pseudo-likelihood method for which the couplings are inferred independently for each spin. Assuming that the data are generated from a true Ising model, we compute the reconstruction error of the couplings using a combination of the replica method with the cavity approach for densely connected systems. We show that an explicit estimator based on a quadratic cost function achieves minimal reconstruction error, but requires the length of the true coupling vector as prior knowledge. A simple mean field estimator of the couplings which does not need such knowledge is asymptotically optimal, i.e. when the number of observations is much larger than the number of spins. Comparison of the theory with numerical simulations shows excellent agreement for data generated from two models with random couplings in the high temperature region: a model with independent couplings (Sherrington-Kirkpatrick model), and a model where the matrix of couplings has a Wishart distribution.

  2. 'You learn better under the gun': intimidation and harassment in surgical education.

    Science.gov (United States)

    Musselman, Laura J; MacRae, Helen M; Reznick, Richard K; Lingard, Lorelei A

    2005-09-01

    Medical literature has documented a high prevalence of intimidation and harassment in the educational context. However, the research has failed to adequately delineate the nature of these phenomena as well as the different ways in which diverse actors perceive the behaviours in question. Based on qualitative methodology anchored in a social constructionism framework, how teachers (staff surgeons) and learners (surgical residents) define intimidation and harassment were documented and compared. In addition, teachers' and learners' perceptions of the impact of these behaviours on the learning environment, including their effects on the socialisation of surgeons in training, were examined. Five group interviews and 22 individual interviews were conducted across 2 university departments of surgery with a total of 22 faculty and 14 resident participants. Interviewees acknowledged the existence of intimidation and harassment, while at the same time rationalising its occurrence. This paradox was encapsulated in participant descriptions using terms such as 'good intimidation'. Our examination of the data helped us to understand that participants sustained the paradox of beneficial intimidation and harassment by rationalising questionable behaviours on 3 specific dimensions, namely: whether an acceptable purpose could be attributed to the perpetrator; whether positive effects of the behaviour existed, and whether there was a perceived necessity for the behaviour. Even while their dysfunctional characteristics are recognised, intimidation and harassment are often seen as functional educational tools. The cultural value currently accorded these behaviours needs to be taken into account in educational interventions designed to shift attitudes and actions in this domain.

  3. 4-Ports endoscopic extraperitoneal radical prostatectomy: preliminary and learning curve results

    Science.gov (United States)

    Barbosa, Humberto do Nascimento; Siqueira, Tiberio Moreno; Barreto, Françualdo; Menezes, Leonardo Gomes; Luna, Mauro José Catunda; Calado, Adriano Almeida

    2016-01-01

    ABSTRACT Introduction There is a lack of studies in our national scenario regarding the results obtained by laparoscopic radical prostatectomy technique (LRP). Except for a few series, there are no consistent data on oncological, functional, and perioperative results on LRP held in Brazil. As for the LRP technique performed by extraperitoneal access (ELRP), when performed by a single surgeon, the results are even scarcer. Objective To analyze the early perioperative and oncologic results obtained with the ELRP, throughout the technical evolution of a single surgeon. Patients and methods A non-randomized retrospective study was held in a Brazilian hospital of reference. In the 5-year period, 115 patients underwent the ELRP procedure. Patients were divided into two groups, the first 57 cases (Group 1) and the following 58 cases, (Group 2). A comparative analysis between the groups of efficacy results and ELRP safety was carried out. Results The average age of patients was 62.8 year-old and the PSA of 6.9ng/dl. The total surgery time was 135.8 minutes on average, and the urethral-bladder anastomosis was 21.9 min (23.3 min versus 20.7 min). The positive surgical margins (PSM) rate was 17.1%, showing no difference between groups (16.4% versus 17.9%; p=0.835). There was statistical difference between the groups in relation to the anastomosis time, estimated blood loss and the withdrawal time of the urinary catheter. Conclusion The ELRP technique proved to be a safe and effective procedure in the treatment of prostate cancer, with low morbidity. PMID:27286105

  4. Incidence of Complications During Initial Experience with Revision of the Agility and Agility LP Total Ankle Replacement Systems: A Single Surgeon's Learning Curve Experience.

    Science.gov (United States)

    Roukis, Thomas S; Simonson, Devin C

    2015-10-01

    As the frequency in which foot and ankle surgeons are performing primary total ankle replacement (TAR) continues to build, revision TAR will likely become more commonplace, creating a need for an established benchmark by which to evaluate the safety of revision TAR as determined by the incidence of complications. Currently, no published data exist on the incidence of intraoperative and early postoperative complications during revision of the Agility or Agility LP Total Ankle Replacement Systems during the surgeon learning curve period; therefore, the authors sought to determine this incidence during the senior author's learning curve period.

  5. LEARNING CURVES OF LAPAROSCOPY – BARRIERS TO ADOPTION: A MNJIO EXPERIENCE!

    Directory of Open Access Journals (Sweden)

    Ramesh Maturi

    2016-06-01

    Full Text Available BACKGROUND Laparoscopy has been a new entry in the field of surgery with an active history of around just two decades. Today, it is in a position to challenge the conventional surgery which is in use since ages. It is making rapid inroads into various disciplines of surgery. Rapid improvements in optics, along with improvements in energy devices and mechanical stapling devices gave a fillip to acceptance of laparoscopy by the majority of surgeons. Also accumulating data and evidence has started influencing the sceptical, mobilising them to jump into the bandwagon. Barriers to adoption of new techniques, resistance to learning are common to human nature and it is necessary to have a systematic overview of the issues that might crop, so as to be prepared to overcome the problems of accepting laparoscopy into established centres of surgery. AIMS This publication is a reflection of our experience, our trials and tribulations in taking forward the laparoscopy program at our institution. This publication will give an overview of the steps involved in initiation of laparoscopy and aspires to be a source of answers, for day-to-day issues that crop during the process of learning laparoscopy. METHODS AND MATERIALS Just the way, executing laparoscopic surgery is a team effort, incorporating laparoscopy program in an institution is also a team effort where the members of team extend beyond the operating room. Involvement and co-operation of individuals across departments is a must along with benevolent seniors and a proactive administration. So we collated data by interviewing all the stakeholders of laparoscopy program, analysed observations of the faculty from the operating room and reviewed literature on the world wide web. Opinions of the administrators about their perceptions and the issues faced by the junior staff of the department were taken into consideration. Patients were interviewed before and after laparoscopic surgery. CONCLUSIONS Success at

  6. Practical skills teaching in contemporary surgical education: how can educational theory be applied to promote effective learning?

    Science.gov (United States)

    Sadideen, Hazim; Kneebone, Roger

    2012-09-01

    Teaching practical skills is a core component of undergraduate and postgraduate surgical education. It is crucial to optimize our current learning and teaching models, particularly in a climate of decreased clinical exposure. This review explores the role of educational theory in promoting effective learning in practical skills teaching. Peer-reviewed publications, books, and online resources from national bodies (eg, the UK General Medical Council) were reviewed. This review highlights several aspects of surgical education, modeling them on current educational theory. These include the following: (1) acquisition and retention of motor skills (Miller's triangle; Fitts' and Posner's theory), (2) development of expertise after repeated practice and regular reinforcement (Ericsson's theory), (3) importance of the availability of expert assistance (Vygotsky's theory), (4) learning within communities of practice (Lave and Wenger's theory), (5) importance of feedback in learning practical skills (Boud, Schon, and Endes' theories), and (6) affective component of learning. It is hoped that new approaches to practical skills teaching are designed in light of our understanding of educational theory. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. Three-dimensional Laparoscopy: Does Improved Visualization Decrease the Learning Curve Among Trainees in Advanced Procedures?

    Science.gov (United States)

    Cologne, Kyle G; Zehetner, Joerg; Liwanag, Loriel; Cash, Christian; Senagore, Anthony J; Lipham, John C

    2015-08-01

    Complex laparoscopy is difficult to master because it involves 3-dimensional (3D) interpretation on a 2-dimensional (2D) viewing screen. The use of 3D technology has an uncertain effect on training surgeons. We aim to evaluate the effectiveness of 3D on learning and performing laparoscopic tasks. Medical students without laparoscopic experience (novices) were evaluated doing inanimate object transfer and laparoscopic suturing. Tasks were repeated using 2D and 3D cameras with standard instruments. Time and error rates (missed attempts, dropped objects, and failure to complete the task) were recorded. Twenty-nine novice medical students experienced a 45.5% decrease in the time to complete PEG transfer using 3D (mean 207 s with 2D vs. 113 s with 3D). Error rate was reduced to 50% (2D, 4 errors vs. 3D, 2 errors) and mean drop rate was reduced to 0. Similar decreases in suture time (46.5%) were seen (mean 403 s with 2D vs. 220 s with 3D). Our results indicate that 3D significantly improved visualization and ability to perform complex tasks in the skills laboratory setting. This technology may be very effective in teaching advanced laparoscopic skills in the era of work-hour restrictions.

  8. A Machine Learning Method to Infer Fundamental Stellar Parameters from Photometric Light Curves

    CERN Document Server

    Miller, A A; Richards, J W; Lee, Y S; Starr, D L; Butler, N R; Tokarz, S; Smith, N; Eisner, J A

    2014-01-01

    A fundamental challenge for wide-field imaging surveys is obtaining follow-up spectroscopic observations: there are > $10^9$ photometrically cataloged sources, yet modern spectroscopic surveys are limited to ~few x $10^6$ targets. As we approach the Large Synoptic Survey Telescope (LSST) era, new algorithmic solutions are required to cope with the data deluge. Here we report the development of a machine-learning framework capable of inferring fundamental stellar parameters (Teff, log g, and [Fe/H]) using photometric-brightness variations and color alone. A training set is constructed from a systematic spectroscopic survey of variables with Hectospec/MMT. In sum, the training set includes ~9000 spectra, for which stellar parameters are measured using the SEGUE Stellar Parameters Pipeline (SSPP). We employed the random forest algorithm to perform a non-parametric regression that predicts Teff, log g, and [Fe/H] from photometric time-domain observations. Our final, optimized model produces a cross-validated root...

  9. Program Setup Time and Learning Curves associated with "ready to fly" Drone Mapping Hardware and Software.

    Science.gov (United States)

    Wilcox, T.

    2016-12-01

    How quickly can students (and educators) get started using a "ready to fly" UAS and popular publicly available photogrammetric mapping software for student research at the undergraduate level? This poster presentation focuses on the challenges of starting up your own drone-mapping program for undergraduate research in a compressed timescale of three months. Particular focus will be given to learning the operation of the platforms, hardware and software interface challenges, and using these electronic systems in real-world field settings that pose a range of physical challenges to both operators and equipment. We will be using a combination of the popular DJI Phantom UAS and Pix4D mapping software to investigate mass wasting processes and potential hazards present in public lands popular with recreational users. Projects are aimed at characterizing active geological hazards that operate on short timescales and may include gully headwall erosion in Flaming Geyser State Park and potential landslide instability within Capital State Forest, both in the Puget Sound region of Washington State.

  10. Use of the cumulative sum method (CUSUM) to assess the learning curves of ultrasound-guided continuous femoral nerve block.

    Science.gov (United States)

    Kollmann-Camaiora, A; Brogly, N; Alsina, E; Gilsanz, F

    2017-10-01

    Although ultrasound is a basic competence for anaesthesia residents (AR) there is few data available on the learning process. This prospective observational study aims to assess the learning process of ultrasound-guided continuous femoral nerve block and to determine the number of procedures that a resident would need to perform in order to reach proficiency using the cumulative sum (CUSUM) method. We recruited 19 AR without previous experience. Learning curves were constructed using the CUSUM method for ultrasound-guided continuous femoral nerve block considering 2 success criteria: a decrease of pain score>2 in a [0-10] scale after 15minutes, and time required to perform it. We analyse data from 17 AR for a total of 237 ultrasound-guided continuous femoral nerve blocks. 8/17 AR became proficient for pain relief, however all the AR who did more than 12 blocks (8/8) became proficient. As for time of performance 5/17 of AR achieved the objective of 12minutes, however all the AR who did more than 20 blocks (4/4) achieved it. The number of procedures needed to achieve proficiency seems to be 12, however it takes more procedures to reduce performance time. The CUSUM methodology could be useful in training programs to allow early interventions in case of repeated failures, and develop competence-based curriculum. Copyright © 2017 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  11. "A steep learning curve": junior doctor perspectives on the transition from medical student to the health-care workplace.

    Science.gov (United States)

    Sturman, Nancy; Tan, Zachary; Turner, Jane

    2017-05-26

    The transition from medical student to hospital-based first year junior doctor (termed "intern" in Australia) is known to be challenging, and recent changes in clinical learning environments may reduce graduate preparedness for the intern workplace. Although manageable challenges and transitions are a stimulus to learning, levels of burnout in junior medical colleagues are concerning. In order to prepare and support medical graduates, educators need to understand contemporary junior doctor perspectives on this transition. Final-year University of Queensland medical students recruited junior doctors working in diverse hospital settings, and videorecorded individual semi-structured interviews about their transition from medical student to working as a junior doctor. Two clinical academics (NS and JT) and an intern (ZT) independently conducted a descriptive analysis of interview transcripts, and identified preliminary emerging concepts and themes, before reaching agreement by consensus on the major overarching themes. Three key themes emerged from the analysis of 15 interviews: internship as a "steep learning curve"; relationships and team; and seeking help. Participants described the intern transition as physically, mentally and emotionally exhausting. They learned to manage long days, administrative and clinical tasks, frequent interruptions and time pressures; identify priorities; deal with criticism without compromising key relationships; communicate succinctly; understand team roles (including their own status within hospital hierarchies); and negotiate conflict. Participants reported a drop in self-confidence, and difficulty maintaining self-care and social relationships. Although participants emphasised the importance of escalating concerns and seeking help to manage patients, they appeared more reluctant to seek help for personal issues and reported a number of barriers to doing so. Findings may assist educators in refining their intern preparation and intern

  12. A MACHINE-LEARNING METHOD TO INFER FUNDAMENTAL STELLAR PARAMETERS FROM PHOTOMETRIC LIGHT CURVES

    Energy Technology Data Exchange (ETDEWEB)

    Miller, A. A. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, MS 169-506, Pasadena, CA 91109 (United States); Bloom, J. S.; Richards, J. W.; Starr, D. L. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Lee, Y. S. [Department of Astronomy and Space Science, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Butler, N. R. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85281 (United States); Tokarz, S. [Smithsonian Astrophysical Observatory, Cambridge, MA 02138 (United States); Smith, N.; Eisner, J. A., E-mail: amiller@astro.caltech.edu [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)

    2015-01-10

    A fundamental challenge for wide-field imaging surveys is obtaining follow-up spectroscopic observations: there are >10{sup 9} photometrically cataloged sources, yet modern spectroscopic surveys are limited to ∼few× 10{sup 6} targets. As we approach the Large Synoptic Survey Telescope era, new algorithmic solutions are required to cope with the data deluge. Here we report the development of a machine-learning framework capable of inferring fundamental stellar parameters (T {sub eff}, log g, and [Fe/H]) using photometric-brightness variations and color alone. A training set is constructed from a systematic spectroscopic survey of variables with Hectospec/Multi-Mirror Telescope. In sum, the training set includes ∼9000 spectra, for which stellar parameters are measured using the SEGUE Stellar Parameters Pipeline (SSPP). We employed the random forest algorithm to perform a non-parametric regression that predicts T {sub eff}, log g, and [Fe/H] from photometric time-domain observations. Our final optimized model produces a cross-validated rms error (RMSE) of 165 K, 0.39 dex, and 0.33 dex for T {sub eff}, log g, and [Fe/H], respectively. Examining the subset of sources for which the SSPP measurements are most reliable, the RMSE reduces to 125 K, 0.37 dex, and 0.27 dex, respectively, comparable to what is achievable via low-resolution spectroscopy. For variable stars this represents a ≈12%-20% improvement in RMSE relative to models trained with single-epoch photometric colors. As an application of our method, we estimate stellar parameters for ∼54,000 known variables. We argue that this method may convert photometric time-domain surveys into pseudo-spectrographic engines, enabling the construction of extremely detailed maps of the Milky Way, its structure, and history.

  13. Use of structure-activity landscape index curves and curve integrals to evaluate the performance of multiple machine learning prediction models

    Directory of Open Access Journals (Sweden)

    LeDonne Norman C

    2011-02-01

    Full Text Available Abstract Background Standard approaches to address the performance of predictive models that used common statistical measurements for the entire data set provide an overview of the average performance of the models across the entire predictive space, but give little insight into applicability of the model across the prediction space. Guha and Van Drie recently proposed the use of structure-activity landscape index (SALI curves via the SALI curve integral (SCI as a means to map the predictive power of computational models within the predictive space. This approach evaluates model performance by assessing the accuracy of pairwise predictions, comparing compound pairs in a manner similar to that done by medicinal chemists. Results The SALI approach was used to evaluate the performance of continuous prediction models for MDR1-MDCK in vitro efflux potential. Efflux models were built with ADMET Predictor neural net, support vector machine, kernel partial least squares, and multiple linear regression engines, as well as SIMCA-P+ partial least squares, and random forest from Pipeline Pilot as implemented by AstraZeneca, using molecular descriptors from SimulationsPlus and AstraZeneca. Conclusion The results indicate that the choice of training sets used to build the prediction models is of great importance in the resulting model quality and that the SCI values calculated for these models were very similar to their Kendall τ values, leading to our suggestion of an approach to use this SALI/SCI paradigm to evaluate predictive model performance that will allow more informed decisions regarding model utility. The use of SALI graphs and curves provides an additional level of quality assessment for predictive models.

  14. Use of portfolios as a learning and assessment tool in a surgical practical session of urology during undergraduate medical training.

    Science.gov (United States)

    Amsellem-Ouazana, Delphine; Van Pee, Dominique; Godin, Veronique

    2006-06-01

    We chose to introduce a portfolio as a learning and assessment tool in a practical training session of urological surgery for undergraduate medical students. Our primary objectives were to develop the students' self reflexive ability in front of complex medical cases and to teach them how to identify their learning needs in a short period of time, on a specific topic. Students completed, during their training session, a portfolio on a urological topic under the constant supervision of a tutor. The students were evaluated on their portfolio's presentation with a 20-point grade grid known in advance. Even in a surgical training session, a portfolio can be a useful learning and assessment tool. It clearly encourages self-reflection and pre-professional practice.

  15. Sentinel lymph node biopsy for breast cancer using methylene blue dye manifests a short learning curve among experienced surgeons: a prospective tabular cumulative sum (CUSUM analysis

    Directory of Open Access Journals (Sweden)

    Valentine Christopher SP

    2009-01-01

    Full Text Available Abstract Background The benefits of sentinel lymph node biopsy (SLNB for breast cancer patients with histologically negative axillary nodes, in whom axillary lymph node dissection (ALND is thereby avoided, are now established. Low false negative rate, certainly with blue dye technique, mostly reflects the established high inherent accuracy of SLNB and low axillary nodal metastatic load (subject to patient selection. SLN identification rate is influenced by volume, injection site and choice of mapping agent, axillary nodal metastatic load, SLN location and skill at axillary dissection. Being more subject to technical failure, SLN identification seems to be a more reasonable variable for learning curve assessment than false negative rate. Methylene blue is as good an SLN mapping agent as Isosulfan blue and is much cheaper. Addition of radio-colloid mapping to blue dye does not achieve a sufficiently higher identification rate to justify the cost. Methylene blue is therefore the agent of choice for SLN mapping in developing countries. The American Society of Breast Surgeons recommends that, for competence, surgeons should perform 20 SLNB but admits that the learning curve with a standardized technique may be "much shorter". One appropriate remedy for this dilemma is to plot individual learning curves. Methods Using methylene blue dye, experienced breast surgeons performed SLNB in selected patients with breast cancer (primary tumor Results The CUSUM plot crossed the SPRT limit line after 8 consecutive, positively identified SLN, signaling achievement of an acceptable level of competence. Conclusion Tabular CUSUM charting, based on a justified choice of parameters, indicates that the learning curve for SLNB using methylene blue dye is completed after 8 consecutive, positively identified SLN. CUSUM charting may be used to plot individual learning curves for trainee surgeons by applying a proxy parameter for failure in the presence of a mentor (such as

  16. Sentinel lymph node biopsy for breast cancer using methylene blue dye manifests a short learning curve among experienced surgeons: a prospective tabular cumulative sum (CUSUM) analysis.

    Science.gov (United States)

    East, Jeffrey M; Valentine, Christopher S P; Kanchev, Emil; Blake, Garfield O

    2009-01-27

    The benefits of sentinel lymph node biopsy (SLNB) for breast cancer patients with histologically negative axillary nodes, in whom axillary lymph node dissection (ALND) is thereby avoided, are now established. Low false negative rate, certainly with blue dye technique, mostly reflects the established high inherent accuracy of SLNB and low axillary nodal metastatic load (subject to patient selection). SLN identification rate is influenced by volume, injection site and choice of mapping agent, axillary nodal metastatic load, SLN location and skill at axillary dissection. Being more subject to technical failure, SLN identification seems to be a more reasonable variable for learning curve assessment than false negative rate. Methylene blue is as good an SLN mapping agent as Isosulfan blue and is much cheaper. Addition of radio-colloid mapping to blue dye does not achieve a sufficiently higher identification rate to justify the cost. Methylene blue is therefore the agent of choice for SLN mapping in developing countries. The American Society of Breast Surgeons recommends that, for competence, surgeons should perform 20 SLNB but admits that the learning curve with a standardized technique may be "much shorter". One appropriate remedy for this dilemma is to plot individual learning curves. Using methylene blue dye, experienced breast surgeons performed SLNB in selected patients with breast cancer (primary tumor chart with sequential probability ratio test (SPRT) limits based on a target identification rate of 85%. The CUSUM plot crossed the SPRT limit line after 8 consecutive, positively identified SLN, signaling achievement of an acceptable level of competence. Tabular CUSUM charting, based on a justified choice of parameters, indicates that the learning curve for SLNB using methylene blue dye is completed after 8 consecutive, positively identified SLN. CUSUM charting may be used to plot individual learning curves for trainee surgeons by applying a proxy parameter for

  17. Evaluation of the learning curve of laparoscopic choledochal cyst excision and Roux-en-Y hepaticojejunostomy in children: CUSUM analysis of a single surgeon's experience.

    Science.gov (United States)

    Wen, Zhe; Liang, Huiying; Liang, Jiankun; Liang, Qifeng; Xia, Huimin

    2017-02-01

    Laparoscopic cyst excision and Roux-en-Y hepaticojejunostomy is gaining popularity as a treatment for choledochal cyst (CDC) in children. However, the learning curve for this challenging laparoscopic procedure has not been addressed. The aim of this study is to determine the characteristics of the learning curve of this procedure. This may guide the training in institutions currently not using this technique. A prospectively collected database comprising all medical records of the first 104 consecutive patients undergoing laparoscopic CDC excision and Roux-en-Y hepaticojejunostomy performed by one surgeon was studied. Multifactorial linear/logistic regression analysis was performed to identify patient-, surgeon-, and procedure-related factors associated with operating times, rates of adverse event, and length of postoperative stay. Cumulative sum analysis demonstrated a learning curve for laparoscopic choledochal cyst excision of 37 cases. Comparing the early with the late experiences (37 vs. 67 cases), the surgeon-specific outcomes significantly improved in terms of operating times (352 vs. 240 min; P learning curve (CLC) (OR 0.68, 95 % CI 0.63-0.73) and adhesion score (ORmiddle 1.25, 95 % CI 1.08-1.45; ORhigh 1.40, 95 % CI 1.20-1.62; compared with the low score); significant predictors of perioperative adverse outcomes were CLC (OR 0.07, 95 % CI 0.02-0.34) and comorbidities prior to the surgery (OR 30.65, 95 % CI 1.71-549.63). The independent predictors of length of postoperative stay included CLC, preoperative comorbidities, and perioperative adverse events. CLC for laparoscopic choledochal cyst excision is 37 cases. After CLC, not only the operative time is reduced, the complications, adverse results, and the length of hospital stay all decreased significantly. The learning curve can be used as the basis for performance guiding the training.

  18. 64-row multi-dector computed tomography coronary image from a center with early experience: first illustration of learning curve

    Institute of Scientific and Technical Information of China (English)

    Sze Piaw CHIN; Tiong Kiam ONG; Wei Ling CHAN; Chee Khoon LIEW; M.Tobias Seyfarth; Fong Yean Yip ALAN; Houng Bang LIEW; Kui Hian SIM

    2006-01-01

    Background and objectives The recent joint ACCF/AHA clinical competence statement on cardiac imaging with multi-detector computed tomography recommended a minimum of 6 months training and 300 contrast examinations, of which the candidate must be directly involved in at least 100 studies. Whether this is adequate to become proficient in interpretation of coronary computed tomogsignificant coronary stenosis in a center with 1 year's experience using a 64-row scanner. Methods A total of 778 patients underwent contrast-enhanced CTA between January and December 2005. Out of these patients, 301 patients also underwent contrast-enhanced conventional coronary angiography (CCA). These patients were divided into 4 groups according to the time the examination was underwent. Group Q1: first quarter of the year (n=20), Group Q2: second quarter (n=128), Group Q3: third quarter (n=134), and Group Results The sensitivity, specificity, positive, and negative predictive values were Q1 - 64%, 89%, 49% and 94%, respectively; Q2 -79%, 96%, 74% and 97%, respectively; Q3 - 78%, 96%, 74%, 97%, respectively, and Q4 - 100% for all. Conclusions In a center with formal training and high caseload, our accuracy in CTA analysis reached a plateau after 6 months experience. Test-bolus protocols produce better image quality and can improve accuracy. New centers embarking on CTA will need to overcome an initial 6-month learning curve depending upon the caseload during which time they should consider correlation with CCA.

  19. Using learning curves on energy-efficient technologies to estimate future energy savings and emission reduction potentials in the U.S. iron and steel industry

    Energy Technology Data Exchange (ETDEWEB)

    Karali, Nihan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Park, Won Young [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); McNeil, Michael A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-06-18

    Increasing concerns on non-sustainable energy use and climate change spur a growing research interest in energy efficiency potentials in various critical areas such as industrial production. This paper focuses on learning curve aspects of energy efficiency measures in the U.S iron and steel sector. A number of early-stage efficient technologies (i.e., emerging or demonstration technologies) are technically feasible and have the potential to make a significant contribution to energy saving and CO2 emissions reduction, but fall short economically to be included. However, they may also have the cost effective potential for significant cost reduction and/or performance improvement in the future under learning effects such as ‘learning-by-doing’. The investigation is carried out using ISEEM, a technology oriented, linear optimization model. We investigated how steel demand is balanced with/without the availability learning curve, compared to a Reference scenario. The retrofit (or investment in some cases) costs of energy efficient technologies decline in the scenario where learning curve is applied. The analysis also addresses market penetration of energy efficient technologies, energy saving, and CO2 emissions in the U.S. iron and steel sector with/without learning impact. Accordingly, the study helps those who use energy models better manage the price barriers preventing unrealistic diffusion of energy-efficiency technologies, better understand the market and learning system involved, predict future achievable learning rates more accurately, and project future savings via energy-efficiency technologies with presence of learning. We conclude from our analysis that, most of the existing energy efficiency technologies that are currently used in the U.S. iron and steel sector are cost effective. Penetration levels increases through the years, even though there is no price reduction. However, demonstration technologies are not economically

  20. Intra-operative 3.0 T magnetic resonance imaging using a dual-independent room: long-term evaluation of time-cost, problems, and learning-curve effect.

    Science.gov (United States)

    Martin, X Pablos; Vaz, G; Fomekong, E; Cosnard, G; Raftopoulos, C

    2011-01-01

    We present a short and comprehensive report of our 39-month experience using a 3.0 T intra-operative magnetic resonance imaging (ioMRI) neurosurgical-MR twin room, including a description of the problems encountered and the associated time-delays. Forty-seven problems were experienced during the 189 ioMRI procedures (two ioMRI were performed in five of the 184 surgical procedures) performed in the 39-month period, including a blocked transfer table, failure of anesthetic monitoring material, and specific MRI-related problems, such as head and coil positioning difficulties, artefacts, coil malfunctions and other technical difficulties. None of these problems prevented the ioMRI procedure from taking place or affected image interpretation, but they sometimes caused a significant delay. Fifteen (32%) of these problems occurred during the initial learning curve period. The mean duration of the ioMRI procedure was 75 min, which decreased slightly with experience, although an average waiting-for-access time of 24 min could not be avoided. These results illustrate that although performing ioMRI at 3.0 T with the dual room is a challenging procedure, it remains safe and feasible and associated with only minor dysfunctions while offering optimal image quality and standard surgical conditions.

  1. Machine learning-based receiver operating characteristic (ROC) curves for crisp and fuzzy classification of DNA microarrays in cancer research.

    Science.gov (United States)

    Peterson, Leif E; Coleman, Matthew A

    2008-01-01

    Receiver operating characteristic (ROC) curves were generated to obtain classification area under the curve (AUC) as a function of feature standardization, fuzzification, and sample size from nine large sets of cancer-related DNA microarrays. Classifiers used included k nearest neighbor (kNN), näive Bayes classifier (NBC), linear discriminant analysis (LDA), quadratic discriminant analysis (QDA), learning vector quantization (LVQ1), logistic regression (LOG), polytomous logistic regression (PLOG), artificial neural networks (ANN), particle swarm optimization (PSO), constricted particle swarm optimization (CPSO), kernel regression (RBF), radial basis function networks (RBFN), gradient descent support vector machines (SVMGD), and least squares support vector machines (SVMLS). For each data set, AUC was determined for a number of combinations of sample size, total sum[-log(p)] of feature t-tests, with and without feature standardization and with (fuzzy) and without (crisp) fuzzification of features. Altogether, a total of 2,123,530 classification runs were made. At the greatest level of sample size, ANN resulted in a fitted AUC of 90%, while PSO resulted in the lowest fitted AUC of 72.1%. AUC values derived from 4NN were the most dependent on sample size, while PSO was the least. ANN depended the most on total statistical significance of features used based on sum[-log(p)], whereas PSO was the least dependent. Standardization of features increased AUC by 8.1% for PSO and -0.2% for QDA, while fuzzification increased AUC by 9.4% for PSO and reduced AUC by 3.8% for QDA. AUC determination in planned microarray experiments without standardization and fuzzification of features will benefit the most if CPSO is used for lower levels of feature significance (i.e., sum[-log(p)] ~ 50) and ANN is used for greater levels of significance (i.e., sum[-log(p)] ~ 500). When only standardization of features is performed, studies are likely to benefit most by using CPSO for low levels

  2. Electromyographic correlates of learning during robotic surgical training in virtual reality.

    Science.gov (United States)

    Suh, Irene H; Mukherjee, Mukul; Schrack, Ryan; Park, Shi-Hyun; Chien, Jung-Hung; Oleynikov, Dmitry; Siu, Ka-Chun

    2011-01-01

    The purpose of this study was to investigate the muscle activation and the muscle frequency response of the dominant arm muscles (flexor carpi radialis and extensor digitorum) and hand muscles (abductor pollicis and first dorsal interosseous) during robotic surgical skills training in a virtual environment. The virtual surgical training tasks consisted of bimanual carrying, needle passing and mesh alignment. The experimental group (n=5) was trained by performing four blocks of the virtual surgical tasks using the da Vinci™ surgical robot. During the pre- and post-training tests, all subjects were tested by performing a suturing task on a "life-like" suture pad. The control group (n=5) performed only the suturing task without any virtual task training. Differences between pre- and post-training tests were significantly greater in the virtual reality group, as compared to the control group in the muscle activation of the hand muscle (abductor pollicis) for both the suture tying and the suture running (pvirtual reality leads to specific changes in neuromotor control of robotic surgical tasks.

  3. Endoscopy-assisted surgery for the management of benign breast tumors: technique, learning curve, and patient-reported outcome from preliminary 323 procedures.

    Science.gov (United States)

    Lai, Hung-Wen; Lin, Hui-Yu; Chen, Shu-Ling; Chen, Shou-Tung; Chen, Dar-Ren; Kuo, Shou-Jen

    2017-01-11

    Endoscopy-assisted breast surgery (EABS), a technique that optimizes cosmetic outcome because it is performed through small wounds hidden in inconspicuous areas, could be an alternative surgical technique for benign breast tumors. In this study, we report the preliminary results of 323 EABS procedures performed at our institution for the management of benign breast tumors. The medical records of patients who underwent EABS for benign breast lesions during the periods August 2010 to December 2015 were collected from the Changhua Christian Hospital EABS database. Data on clinicopathologic characteristics, type of surgery, hospital stay, and complications were analyzed to determine the effectiveness of the procedure for benign breast tumors. The operating time with the number of procedure performed was analyzed for learning curve evaluation. Patient satisfaction with cosmetic outcome was evaluated with a self-report questionnaire. A total of 323 EABS procedures were performed in 286 patients with benign breast lesions, including 249 (90.5%) patients with unilateral lesions. The mean age was 36 years, the mean tumor size was 2.2 cm, and the mean distance from the nipple to the tumor was 5.2 cm. Most (93.8%, 303/323) of these tumors were excised through a transareolar wound, 2.4% (8/323) through an axillary wound, and 0.3% (1/323) through the infra-mammary fold. Histopathologic analysis revealed that 63.5% (202/318) of the tumors were fibroadenoma-related lesions. The mean operative time was 81.4 min (59~89 min), which was decreased with experience increased. The overall rate of complications was 6.5%, and all were minor and wound-related. Among the 110 patients who participated in the self-report cosmetic outcome evaluation, 85.4% reported being satisfied with the cosmetic result, and almost all were satisfied with breast symmetry. Of the patients interviewed, 92.7% reported that they would choose the same procedure if they had to undergo the operation again. Our

  4. The learning curve for robotic distal pancreatectomy: an analysis of outcomes of the first 100 consecutive cases at a high-volume pancreatic centre

    Science.gov (United States)

    Shakir, Murtaza; Boone, Brian A; Polanco, Patricio M; Zenati, Mazen S; Hogg, Melissa E; Tsung, Allan; Choudry, Haroon A; Moser, A James; Bartlett, David L; Zeh, Herbert J; Zureikat, Amer H

    2015-01-01

    Background Robotic distal pancreatectomy (RDP) is performed increasingly, but knowledge of the number of cases required to attain procedural proficiency is lacking. The aim of this study was to identify the learning curve associated with RDP at a high-volume pancreatic centre. Methods Metrics of perioperative safety and efficiency for all consecutive RDPs were evaluated. Outcomes were followed to 90 days. Cumulative sum (CUSUM) analysis was used to identify inflexion points corresponding to the learning curve. Results Between 2008 and 2013, 100 patients underwent RDP. There was no 90-day mortality. In two patients (2.0%), surgery was converted to laparotomy. Thirty procedures were performed for pancreatic adenocarcinoma. Precipitous operative time reductions from an initial operative time of 331 min were observed after the first 20 and 40 cases to 266 min and 210 min, respectively (P < 0.0001). The likelihood of readmission was significantly lower after the first 40 cases (P = 0.04), and non-significant reductions were observed in incidences of major (Clavien–Dindo Grade II or higher) morbidity and Grade B and C leaks, and length of stay. Conclusions In this experience, RDP outcomes were optimized after 40 cases. Familiarity with the platform and dedicated training are likely to contribute to significantly shorter learning curves in future adopters. PMID:25906690

  5. HOW MANY REPETITIONS OF CHILD CARE SKILLS ARE REQUIRED FOR HEALTH WORKER STUDENTS TO ACHIEVE PROFICIENCY? LEARNING CURVE PATTERNS IN CHILD CARE SKILLS ACQUISITION.

    Science.gov (United States)

    Moghadam, Zahra Emami; Emami Zeydi, Amir; Mazlom, Seyed Reza; Abadi, Fatemeh Sardar; Pour, Parastoo Majidi; Davoudi, Malihe; Banafsheh, Elahe

    2015-10-01

    The vulnerability of children under 5 years old requires paying more attention to the health of this group. In the Iranian health care system, health workers are the first line of human resources for health care in rural areas. Because most health workers begin working in conditions with minimal facilities, their clinical qualifications are crucial. The aim of this study was to determine the number of repetitions of child care skills, required for health worker students to achieve proficiency based on the learning curve. A time series research design was used. Participants in this study were first year health worker students enrolled in three health schools in 2011. Data were collected using a questionnaire consisting of demographic information and a checklist evaluating the health worker students' clinical skills proficiency for child care. Data were analyzed using SPSS version 16.0 software (SPSS Inc., Chicago, IL) using descriptive and inferential statistics including Kruskal-Wallis and Pearson correlation coefficient tests. Learning curve patterns in child care skills acquisition showed that for less than 20 and between 20 to 29 times, the level of skill acquisition had an upward slope. Between 30- 39 the learning curve was descending, however the slope became ascending once more and then it leveled off (with change of less than 5%). It seems that 40 repetitions of child care skills are sufficient for health worker students to achieve proficiency. This suggests that time, resources and additional costs for training health worker students' trainees can be saved by this level of repetition.

  6. Impact of learning curve and technical changes on dosimetry in low-dose brachytherapy for prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Le Fur, E. [CHU Brest (France). Radiation Therapy Dept.; Universite de Bretagne Occidentale, Brest (France). Faculte de Medecine et des Sciences de la Sante; Malhaire, J.P.; Baverez, D.; Schlurmann, F. [CHU Brest (France). Radiation Therapy Dept.; Delage, F.; Perrouin-Verbe, M.A. [CHU Brest (France). Urology Dept.; Guerif, S. [University Hospital La Miletrie, Poitiers (France). Radiation Therapy Dept.; Poitiers Univ. (France); Fournier, G.; Valeri, A. [CHU Brest (France). Urology Dept.; Universite de Bretagne Occidentale, Brest (France). Faculte de Medecine et des Sciences de la Sante; Universite Europeenne de Bretagne, Rennes (France); APHP, Hopital Tenon, Paris (France). CeRe.PP; Pradier, O. [CHU Brest (France). Radiation Therapy Dept.; Universite de Bretagne Occidentale, Brest (France). Faculte de Medecine et des Sciences de la Sante; Universite Europeenne de Bretagne, Rennes (France); CHU Brest (France). LaTIM, INSERM U650

    2012-12-15

    Purpose: To assess the impact of experience and technical changes on peri- and postimplantation (1 month later) dosimetry for permanent prostate brachytherapy (PPB). Patients and methods: From July 2003 to May 2010, 150 prostate cancer patients underwent low-dose, loose-seed I{sup 125} PPB as monotherapy with intraoperative planning. Patients were divided into three groups - P1 (n = 64), P2 (n = 45), P3 (n = 41) - according to the technical changes that occurred during the study period: use of an automatic stepper at the beginning of P2 and a high-frequency ultrasound probe in P3. Peri- and postimplantation dosimetric parameters (on day 30) were reported: D90 (dose received by 90% of prostate volume), V100 and V150 (prostate volume receiving, respectively, 100% and 150% of the prescribed dose), D2 cc and D0.1 cc (doses received by 2 cc and 0.1 cc of the rectum), R100 (rectum volume that received 100% of the prescribed dose), and D10 and D30 (doses received by 10% and 30% of the urethra, only during peri-implantation). Results: We observed a decrease in the number of needles and seeds used over time. The mean peri-implantation D90 was 187.52 Gy without a significant difference between the three periods (p = 0.48). The postimplantation D90, V100, and V150 parameters were, respectively, 168.3 Gy, 91.9%, and 55% with no significant difference between the three periods. The peri-implantation and postimplantation D0.1 cc and R100 significantly decreased over time; on day 30: D0.1 cc P1 = 223.1 Gy vs. D0.1 cc P3 = 190.4 Gy (p = 8.10- 5) and R100 P1 = 1.06 cc vs. R100 P3 = 0.53 cc (p = 0.0008). Conclusion: We observed a learning curve for the implantation parameters, which led to a significant decrease in the rectal doses without having any impact on the prostate dosimetric parameters. (orig.)

  7. Learning thoracoscopic lobectomy

    DEFF Research Database (Denmark)

    Petersen, René Horsleben; Hansen, Henrik Jessen

    2010-01-01

    Thoracoscopic (video-assisted thoracoscopic surgery (VATS)) lobectomy is a safe and effective method for treating early-stage lung cancer. Despite this, it is still not widely practised, which could be due to a shallow learning curve. We have evaluated the surgical outcome in a training programme...... at an institution with an established VATS lobectomy programme. We present the surgical data and outcome of the first 50 intended VATS lobectomies performed by a consultant in training as the primary surgeon....

  8. Surgical management of aortopulmonary window: 24 years of experience and lessons learned.

    Science.gov (United States)

    Gowda, Deepak; Gajjar, Trushar; Rao, Jinaga Nageswar; Chavali, Praveen; Sirohi, Aaditya; Pandarinathan, Naveen; Desai, Neelam

    2017-05-05

    Aortopulmonary window represents 0.2-0.3% of all congenital heart lesions. Progressive pulmonary arterial hypertension and its consequences are more common with this anomaly. The purpose of this study was to share 24 years of surgical experience in managing a spectrum of 55 cases of aortopulmonary window, followed up to 17 years in a single institution. : This retrospective study was done from November 1991 to November 2015 of 55 patients with aortopulmonary window who underwent successful surgical repair. Age ranged from 5 months to 31 years with 45 children (12 years and younger) and 10 adults (older than 12 years). The male:female ratio was 2.2:1. The mean weight at operation was 14.63 kg (range 3.5-50 kg). An initial diagnosis was obtained from 2D echocardiography, which showed echo dropout in the parasternal short-axis view. Cardiac catheterization and angiography were performed in 54 out of 55 patients. Cardiac catheterization was not done in 1 patient who was 4 months of age. The mean right ventricular systolic pressure (RVSP) was 94 ± 2 mmHg, and the pulmonary artery mean pressure was 68 ± 2 mmHg. The average left to right shunt was 5.2:1, and the pulmonary vascular resistance index in room air was 7.97 ± 0.5 Wood units, whereas after oxygen administration, it declined to 2.0 ± 0.5 Wood units. Four surgical techniques were used based on the size of the communication and the anatomical conditions. There were no early or late deaths. There were no pulmonary hypertensive crises. All patients underwent echocardiography before discharge; none showed a residual shunt. Mild left ventricular dysfunction was seen in 2 patients. This dysfunction regressed with afterload reduction and diuretics on follow-up. All patients were followed up at intervals of 3 months, 1, 5 and 10 years, with the longest follow-up being 17 years. The mean follow-up period was 7 years. At follow-up, all patients were New York Heart Association class I. The mean

  9. Data-driven methods towards learning the highly nonlinear inverse kinematics of tendon-driven surgical manipulators.

    Science.gov (United States)

    Xu, Wenjun; Chen, Jie; Lau, Henry Y K; Ren, Hongliang

    2017-09-01

    Accurate motion control of flexible surgical manipulators is crucial in tissue manipulation tasks. The tendon-driven serpentine manipulator (TSM) is one of the most widely adopted flexible mechanisms in minimally invasive surgery because of its enhanced maneuverability in torturous environments. TSM, however, exhibits high nonlinearities and conventional analytical kinematics model is insufficient to achieve high accuracy. To account for the system nonlinearities, we applied a data driven approach to encode the system inverse kinematics. Three regression methods: extreme learning machine (ELM), Gaussian mixture regression (GMR) and K-nearest neighbors regression (KNNR) were implemented to learn a nonlinear mapping from the robot 3D position states to the control inputs. The performance of the three algorithms was evaluated both in simulation and physical trajectory tracking experiments. KNNR performed the best in the tracking experiments, with the lowest RMSE of 2.1275 mm. The proposed inverse kinematics learning methods provide an alternative and efficient way to accurately model the tendon driven flexible manipulator. Copyright © 2016 John Wiley & Sons, Ltd.

  10. Learning thoracoscopic lobectomy

    DEFF Research Database (Denmark)

    Petersen, René Horsleben; Hansen, Henrik Jessen

    2010-01-01

    Thoracoscopic (video-assisted thoracoscopic surgery (VATS)) lobectomy is a safe and effective method for treating early-stage lung cancer. Despite this, it is still not widely practised, which could be due to a shallow learning curve. We have evaluated the surgical outcome in a training programme...

  11. Generating a learning curve for penile block in neonates, infants and children: an empirical evaluation of technical skills in novice and experienced anaesthetists.

    Science.gov (United States)

    Schuepfer, Guido; Jöhr, Martin

    2004-07-01

    Literature concerning learning curves for anaesthesiological procedures in paediatric anaesthesia is rare. The aim of this study was to assess the number of penile blocks needed to guarantee a high success rate in children. At a teaching hospital, the technical skills of 29 residents in anaesthesiology who performed penile blocks under the supervision of two staff anaesthesiologists were evaluated during a 12-month period using a standardized self-evaluation questionnaire. At the start of the study period, the residents had no prior experience in paediatric anaesthesia or in performing penile block. All residents entered the paediatric rotation after a minimum of 1-year training in adult general and regional anaesthesia. The blocks were rated using a binary score. For comparison, the success rates of the two supervising staff anaesthesiologists were collected during the same period using the same self-evaluation questionnaire. Statistical analyses were performed by generating individual and institutional learning curves by using the pooled data. The learning curves were calculated with the aid of a least square fit model. A 95% CI were estimated by a Monte Carlo procedure with a bootstrap technique. In a total number of 392 blocks performed, the overall success rate was 92.1%. There was no statistical difference between the success rate of the two staff members (success rate: 96.3%) and the overall success rate of the 29 residents performing a total of 339 blocks. The total success rate for this group was 91.5%. The failure rate for the first 10 blocks performed by the residents was 8.82% (95% CI: 5.0-14.14%), it was 4.12% (95% CI: 1.13-10.22%) for the next 10 blocks and from blocks 21 to 40 it was 6.5% (95% CI: 2.65-12.9%). For blocks 41-60, the failure rate was 4.4% (95% CI 0.54-15.15%). Penile block in children is easily learned by residents. A steep learning curve was found. The success rate was over 93.5% after more than 40 blocks. Copyright 2004 Blackwell

  12. Survey compare team based learning and lecture teaching method, on learning-teaching process nursing student\\'s, in Surgical and Internal Diseases course

    Directory of Open Access Journals (Sweden)

    AA Vaezi

    2015-12-01

    Full Text Available Introduction: The effect of teaching methods on learning process of students will help teachers to improve the quality of teaching by selecting an appropriate method. This study aimed to compare the team- based learning and lecture teaching method on learning-teaching process of nursing students in surgical and internal diseases courses. Method: This quasi-experimental study was carried on the nursing students in the School of Nursing and Midwifery in Yazd and Meybod cities. Studied sample was all of the students in the sixth term in the Faculty of Nursing in Yazd (48 persons and the Faculty of Nursing in Meybod (28 persons. The rate of students' learning through lecture was measured using MCQ tests and teaching based on team-based learning (TBL method was run using MCQ tests (IRAT, GRAT, Appeals and Task group. Therefore, in order to examine the students' satisfaction about the TBL method, a 5-point Likert scale (translated questionnaire (1=completely disagree, 2= disagree, 3=not effective, 4=agree, and 5=completely agree consisted of 22 items was utilized. The reliability and validity of this translated questionnaire was measured. The collected data were analyzed through SPSS 17.0 using descriptive and analytical statistic. Result: The results showed that the mean scores in team-based learning were meaningful in individual assessment (17±84 and assessment group (17.2±1.17. The mean of overall scores in TBL method (17.84±0.98% was higher compared with the lecture teaching method (16±2.31. Most of the students believed that TBL method has improved their interpersonal and group interaction skills (100%. Among them, 97.7% of students mentioned that this method (TBL helped them to understand the course content better. The lowest levels of the satisfaction have related to the continuous learning during lifelong (51.2%. Conclusion: The results of the present study showed that the TBL method led to improving the communication skills, understanding

  13. Fostering pupils’ lifelong learning competencies in the classroom : evaluation of a training programme using a multivariate multilevel growth curve approach

    NARCIS (Netherlands)

    Lüftenegger, Marko; Finsterwald, Monika; Klug, Julia; Bergsmann, Evelyn; van de Schoot, Rens; Schober, Barbara; Wagner, Petra

    2016-01-01

    Evidence-based interventions to promote lifelong learning are needed not only in continuing education but also in schools, which lay important cornerstones for lifelong learning. The present article reports evaluation results about the effectiveness of one such training programme (TALK). TALK aims

  14. It Pays to Go Off-Track: Practicing with Error-Augmenting Haptic Feedback Facilitates Learning of a Curve-Tracing Task.

    Science.gov (United States)

    Williams, Camille K; Tremblay, Luc; Carnahan, Heather

    2016-01-01

    Researchers in the domain of haptic training are now entering the long-standing debate regarding whether or not it is best to learn a skill by experiencing errors. Haptic training paradigms provide fertile ground for exploring how various theories about feedback, errors and physical guidance intersect during motor learning. Our objective was to determine how error minimizing, error augmenting and no haptic feedback while learning a self-paced curve-tracing task impact performance on delayed (1 day) retention and transfer tests, which indicate learning. We assessed performance using movement time and tracing error to calculate a measure of overall performance - the speed accuracy cost function. Our results showed that despite exhibiting the worst performance during skill acquisition, the error augmentation group had significantly better accuracy (but not overall performance) than the error minimization group on delayed retention and transfer tests. The control group's performance fell between that of the two experimental groups but was not significantly different from either on the delayed retention test. We propose that the nature of the task (requiring online feedback to guide performance) coupled with the error augmentation group's frequent off-target experience and rich experience of error-correction promoted information processing related to error-detection and error-correction that are essential for motor learning.

  15. Do We Need to Clamp the Renal Hilum Liberally during the Initial Phase of the Learning Curve of Robot-Assisted Nephron-Sparing Surgery?

    OpenAIRE

    Ömer Acar; Tarık Esen; Ahmet Musaoğlu; Metin Vural

    2014-01-01

    Research Article Do We Need to Clamp the Renal Hilum Liberally during the Initial Phase of the Learning Curve of Robot-Assisted Nephron-Sparing Surgery? Ömer Acar,1 TarJk Esen,1,2 AhmetMusaoLlu,1 andMetin Vural3 1 Department of Urology, VKF American Hospital, 34365 Istanbul, Turkey 2School ofMedicine, KocUniversity, 34450 Istanbul, Turkey 3Department of Radiology, VKF American Hospital, 34365 Istanbul, Turkey Correspondence should be addressed to ¨ Omer Acar; omer acar...

  16. Is In-Vivo laparoscopic simulation learning a step forward in the Undergraduate Surgical Education?

    Directory of Open Access Journals (Sweden)

    Panteleimon Pantelidis

    2017-04-01

    Conclusions: The inexpensive, but low-fidelity “FLS” model could serve an equal alternative Simulation-Based Learning model for the early undergraduate training. Our study demonstrated that high fidelity In Vivo simulation for laparoscopic skills does not affect significantly the improvement in the delegates' performance at the undergraduate level. Further studies should be conducted to identify at which stage of training should high fidelity simulation be introduced.

  17. Surgical innovation: the ethical agenda: A systematic review.

    Science.gov (United States)

    Broekman, Marike L; Carrière, Michelle E; Bredenoord, Annelien L

    2016-06-01

    The aim of the present article was to systematically review the ethics of surgical innovation and introduce the components of the learning health care system to guide future research and debate on surgical innovation.Although the call for evidence-based practice in surgery is increasingly high on the agenda, most surgeons feel that the format of the randomized controlled trial is not suitable for surgery. Innovation in surgery has aspects of, but should be distinguished from both research and clinical care and raises its own ethical challenges.To answer the question "What are the main ethical aspects of surgical innovation?", we systematically searched PubMed and Embase. Papers expressing an opinion, point of view, or position were included, that is, normative ethical papers.We included 59 studies discussing ethical aspects of surgical innovation. These studies discussed 4 major themes: oversight, informed consent, learning curve, and vulnerable patient groups. Although all papers addressed the ethical challenges raised by surgical innovation, surgeons hold no uniform view of surgical innovation, and there is no agreement on the distinction between innovation and research. Even though most agree to some sort of oversight, they offer different alternatives ranging from the formation of new surgical innovation committees to establishing national registries. Most agree that informed consent is necessary for innovative procedures and that surgeons should be adequately trained to assure their competence to tackle the learning curve problem. All papers agree that in case of vulnerable patients, alternatives must be found for the informed consent procedure.We suggest that the concept of the learning health care system might provide guidance for thinking about surgical innovation. The underlying rationale of the learning health care system is to improve the quality of health care by embedding research within clinical care. Two aspects of a learning health care system might

  18. Learning curves in highly skilled chess players: a test of the generality of the power law of practice.

    Science.gov (United States)

    Howard, Robert W

    2014-09-01

    The power law of practice holds that a power function best interrelates skill performance and amount of practice. However, the law's validity and generality are moot. Some researchers argue that it is an artifact of averaging individual exponential curves while others question whether the law generalizes to complex skills and to performance measures other than response time. The present study tested the power law's generality to development over many years of a very complex cognitive skill, chess playing, with 387 skilled participants, most of whom were grandmasters. A power or logarithmic function best fit grouped data but individuals showed much variability. An exponential function usually was the worst fit to individual data. Groups differing in chess talent were compared and a power function best fit the group curve for the more talented players while a quadratic function best fit that for the less talented. After extreme amounts of practice, a logarithmic function best fit grouped data but a quadratic function best fit most individual curves. Individual variability is great and the power law or an exponential law are not the best descriptions of individual chess skill development.

  19. Development and evaluation of the e-learning teaching materials for surgical nursing training.

    Science.gov (United States)

    Matsuda, Yoshimi; Takeuchi, Tomiko; Takahashi, Yukiko; Ozawa, Kazuhiro; Nishimoto, Yutaka; Terauti, Hidemasa

    2006-01-01

    We investigated e-learning teaching materials with a questionnaire for 55 nursing students. Students thought the materials easy to use. In addition, the teaching materials which we developed gave them the confidence of thinking, "I can do it". We affect training by imaging a nursing procedure and think anxiety to training to be be relieved. However, load of PC became high in these teaching materials to display of two motion pictures simultaneously in one screen, so it would be necessary to produce the teaching materials considered transmission rate.

  20. Current status of adult-to-adult living donor liver transplantation: surgical techniques and innovations

    Institute of Scientific and Technical Information of China (English)

    YAN Lü-nan; WU Hong; CHEN Zhe-yu; LIN Yi-xin

    2009-01-01

    @@ In response to critical organ shortage, transplant surgeons have utilized living donors in an attempt to decrease the mortality rate associated with waiting on the liver transplant list. Although the surgical techniques were first utilized clinically 15 years ago, the application of living donor liver transplantation (LDLT) has been somewhat limited by the steep learning curve associated with developing a program.

  1. Abortion - surgical

    Science.gov (United States)

    Suction curettage; Surgical abortion; Elective abortion - surgical; Therapeutic abortion - surgical ... Surgical abortion involves dilating the opening to the uterus (cervix) and placing a small suction tube into the uterus. ...

  2. Open suprapubic versus retropubic prostatectomy in the treatment of benign prostatic hyperplasia during resident's learning curve: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Arie Carneiro

    2016-04-01

    Full Text Available ABSTRACT Purpose: This study compared the suprapubic (SP versus retropubic (RP prostatectomy for the treatment of large prostates and evaluated perioperative surgical morbidity and improvement of urinary symptoms. Materials and Methods: In this single centre, prospective, randomised study, 65 consecutive patients with LUTS and surgical indication with prostate volume greater than 75g underwent open prostatectomy to compare the RP (32 patients versus SP (33 patients technique. Results: The SP group exhibited a higher incidence of complications (p=0.002. Regarding voiding pattern analysis (IPSS and flowmetry, both were significantly effective compared to pre-treatment baseline. The RP group parameters were significantly better, with higher peak urinary flow (SP: 16.77 versus RP: 23.03mL/s, p=0.008 and a trend of lower IPSS score (SP: 6.67 versus RP 4.14, p=0.06. In a subgroup evaluation of patients with prostate volumes larger than 100g, blood loss was lower in those undergoing SP prostatectomy (p=0.003. Patients with prostates smaller than 100g in the SP group exhibited a higher incidence of low grade late complications (p=0.004. Conclusions: The SP technique was related to a higher incidence of minor complications in the late postoperative period. High volume prostates were associated with increased bleeding when the RP technique was utilized. The RP prostatectomy was associated with higher peak urinary flow and a trend of a lower IPSS Score.

  3. 机器人结直肠癌根治术的学习曲线%Learning curve of robot-assisted laparoscopic radical resection for colorectal carcinoma

    Institute of Scientific and Technical Information of China (English)

    刘东宁; 唐城; 江群广; 李太原

    2016-01-01

    目的:评估机器人结直肠癌根治术不同阶段的手术效果,探讨机器人结直肠癌根治术学习曲线问题。方法分析2014年12月至2015年8月由同一组医师完成的75例腹腔镜结直肠癌根治术,按手术先后次序分3组(A、B、C),每组25例,比较各组机器人安装时间、手术时间、出血量、肛门排气时间、术后住院天数、术后并发症和3站淋巴结清扫数目及其总数的差异。结果 A组机器人安装时间(38±5)min,显著长于B组(22±4)min和C组(21±2)min(P均<0.05);A组手术时间(201±39)min,显著长于B组(160±42)min和C组(156±43)min(P均<0.05);A 组出血量(142±35)ml,显著多于B组(105±28)ml和C组(102±28)ml(P均<0.05)。3组肛门排气时间、术后住院天数、术后并发症和3站淋巴结清扫数目及其总数无显著性差异(P>0.05)。A组手术25例在4个月内完成,平均每月6.3台手术,B组和C组均在2个月内完成,平均每月12.5台手术。结论有丰富腹腔镜结直肠癌手术经验的外科医师行机器人结直肠癌根治术的学习曲线大约为25例,手术频度为平均每月6.3例。%ObjectiveTo evaluate the outcomes of robot-assisted laparoscopic radical colorectal resection and to define the learning curve of robot-assisted laparoscopic radical colorectal resections. MethodsClinical data of 75 cases underwent robot-assisted laparoscopic radical resection for colorectal cancer were reviewed form December 2014 to August 2015.The patients were divided into 3 groups (groups A, B and C) by operative sequence.The robotic set-up time, operating time, bleeding volume, postoperative aerofluxus time, hospital stay, postoperative complications, number of removed lymphatic nodes were compared among the 3 groups.ResultsThe robotic set-up time in group A was significantly longer than that in group B and C [ (38± 5) min vs. (22± 4) min,P0.05). The

  4. Virtual reality simulator for training on photoselective vaporization of the prostate with 980 nm diode laser and learning curve of the technique.

    Science.gov (United States)

    Angulo, J C; Arance, I; García-Tello, A; Las Heras, M M; Andrés, G; Gimbernat, H; Lista, F; Ramón de Fata, F

    2014-09-01

    The utility of a virtual reality simulator for training of the photoselective vaporization of the prostate with diode laser was studied. Two experiments were performed with a simulator (VirtaMed AG, Zürich, Switzerland) with software for specific training in prostate vaporization in contact mode with Twister fiber (Biolitec AG, Jena, German). Eighteen surgeons performed ablation of the prostate (55 cc) twice and compared the score obtained (190 points efficacy and 80 safety) in the second one of them by experience groups (medical students, residents, specialists). They also performed a spatial orientation test with scores of 0 to 6. After, six of these surgeons repeated 15 ablations of the prostate (55 and 70 ml). Improvement of the parameters obtained was evaluated to define the learning curve and how experience, spatial orientation skills and type of sequences performed affects them. Global efficacy and safety score was different according to the grade of experience (P=.005). When compared by pairs, specialist-student differences were detected (p=0.004), but not specialist-resident (P=.12) or resident-student (P=.2). Regarding efficacy of the procedure, specialist-student (p=0.0026) and resident-student (P=.08) differences were detected. The different partial indicators in terms of efficacy were rate of ablation (P=.01), procedure time (P=.03) and amount of unexposed capsule (p=0.03). Differences were not observed between groups in safety (P=.5). Regarding the learning curve, percentage median on the total score exceeded 90% after performing 4 procedures for prostates of 55 ml and 10 procedures for prostate glands of 70 ml. This course was not modified by previous experience (resident-specialist; P=.6). However, it was modified according to the repetition sequence (progressive-random; P=.007). Surgeons whose spatial orientation was less than the median of the group (value 2.5) did not surpass 90% of the score in spite of repetition of the procedure. Simulation

  5. The learning curve effect on embolization of cerebral dural arteriovenous fistula single-center experience in 48 consecutive patients.

    Science.gov (United States)

    Le Foll, D; Raoult, H; Ferré, J C; Naudet, F; Trystram, D; Gauvrit, J Y

    2017-02-01

    Cerebral dural arteriovenous fistulas (DAVFs) are rare intracranial vascular lesions but can cause significant morbidity and mortality. To analyze the effect of the center's experience on DAVF embolization efficacy and safety. From May 2008 to October 2014, 57 embolization procedures were attempted on 48 patients (37 men and 11 women; median age: 63.9 years) for DAVF in a single center. DAVF presented with cortical venous reflux in 44/48 cases (91.7%) and hemorrhagic manifestation in 21/48 cases (43.75%). Angiographic occlusion quality, whether complete or incomplete (efficacy), and neurological complications (safety) were recorded. The patient population was divided into four consecutive quartiles during the inclusion period to assess the progress profile. Efficacy and safety outcomes were compared with Fisher's test. A logistic regression was performed to explore a learning curve phenomenon, showing a significant association between the chronological rank in the cohort and embolization efficacy (P=0.007). Significant differences were found between first and last quarter (P=0.036). The endovascular technique involved an arterial injection of Onyx(®) in 36/48 cases (75%), administered via the middle meningeal artery in 25/36 cases (69.5%). The complete occlusion rate improved significantly from 33.3% for the first quartile of the population, to 75.0% for the 2nd and 3rd quartiles and 83.3% for the last quartile. Neurological complications were found in 7/48 patients (14.6%), the rate decreased by 41.7% to 16.7%, without statistically difference. The efficacy and safety of DAVF embolization improved with the experience gained at the center, suggesting the existence of a learning curve. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  6. The radius surgical system - a new device for complex minimally invasive procedures in urology?

    Science.gov (United States)

    Frede, Thomas; Hammady, Ahmed; Klein, Jan; Teber, Dogu; Inaki, Noriyuki; Waseda, Masahiro; Buess, Gerhard; Rassweiler, Jens

    2007-04-01

    Complex laparoscopic procedures in urology are technically demanding with an extended learning curve. Robotic systems add significant cost to laparoscopic procedures. We therefore evaluated the use of the Radius Surgical System (RSS), a mechanical manipulator, for complex laparoscopic cases in urology. The RSS (Tuebingen Scientific) consists of two hand-guided surgical manipulators and provides a deflectable and rotatable tip allowing six degrees of freedom. We evaluated the system by using a series of standardized models in the pelvitrainer. We analyzed the effectiveness of the system and the learning curve. We then evaluated the system in the clinical setting during laparoscopic radical prostatectomy. Surgeons with experience on the RSS were compared to surgeons without previous experience on the system. We identified a learning curve in those participants without experience on the system only when performing complete anastomoses in the pelvitrainer. However, this learning curve included less than 10 anastomoses. The first clinical experiences during laparoscopic extraperitoneal radical prostatectomy (n=10) are promising. All anastomoses were patent on routine (X-ray) examination 8 days after surgery. The RSS system is easy to use and we identified a very short learning curve. We now optimize the system for use in urology. This device may facilitate complex laparoscopic procedures without the use of costly robotic systems and should be further evaluated in the experimental and clinical setting.

  7. Surgical Assisting

    Science.gov (United States)

    ... Insert and remove Foley urinary bladder catheter Place pneumatic tourniquet Confirm procedure with surgeon Drape patient within ... Technology and Surgical Assisting (NBSTSA) offers the CertifiedSurgical First Assistant (CSFA) credential, and the National Surgical Assistant ...

  8. Anxiety in veterinary surgical students

    DEFF Research Database (Denmark)

    Langebæk, Rikke; Eika, Berit; Jensen, Asger Lundorff

    2012-01-01

    The surgical educational environment is potentially stressful and this can negatively affect students' learning. The aim of this study was to investigate whether veterinary students' level of anxiety is higher in a surgical course than in a non-surgical course and if pre-surgical training...... in a Surgical Skills Lab (SSL) has an anxiety reducing effect. Investigations were carried out as a comparative study and a parallel group study. Potential participants were fourth-year veterinary students who attended a surgical course (Basic Surgical Skills) and a non-surgical course (Clinical Examination...... and 28 students from 2010). Our results show that anxiety levels in veterinary students are significantly higher in a surgical course than in a non-surgical course (p...

  9. From the curve of the snake, and the scene of the crocodile: musings on learning and losing space, place and body

    Directory of Open Access Journals (Sweden)

    Susanne Gannon

    2012-12-01

    Full Text Available Where else can educational research begin and end, if not with the body of the researcher, if not with the particular material/ corporeal/ affective assemblages that this body is and has been part of? This paper traces the mutual constitution of bodies, identities and landscapes through memory as the body of this educator travels through multiple scenes of geo-spatial-temporal movement, and down the east coast of Australia. This movement parallels the movement from being a school teacher to becoming an academic. Throughout the paper landscape is foregrounded, and the body in landscape is evoked through poetic and literary modes of writing around the themes of learning and losing. The body in landscape is not merely the body of the writer. Other bodies in the landscape include ‘the curve of the snake’ - the row of protective hills that were said to protect her tropical home from cyclones – and the ‘scene of the crocodile’ – the rock that hung over the valley she passed on her way to school that she had learned of from Indigenous teachers. The political and ethical consequences of memory work, of body and place writing, and of genres of writing in educational research, are also considered. The paper argues for an embodied and reflexive literacy of place that incorporates multiple modes of knowing, being and writing.

  10. Applied Remote Sensing Education and Training (ARSET): Opportunities to shorten the learning curve in use of NASA satellite data products

    Science.gov (United States)

    Kleidman, R. G.; Prados, A. I.; Christopher, S. A.

    2010-12-01

    The previous decade has provided ample opportunity to use observations from space to constrain and enhance aerosol modeling efforts, but we find that the typical modeling professional outside of the immediate NASA environment is often overwhelmed by the breadth and depth of NASA satellite data products. NASA has invested in creating ARSET to help users learn and navigate through the maze of atmospheric products available. ARSET activities include training workshops which run from 1 to 5 days, creating educational materials and monthly air quality case study exercises in contest format. Our workshops provide what nobody else does: a clear and concise training on how to obtain and make proper use of atmospheric remote sensing products. Although our focus is on air quality applications we provide information that can be used by anyone wishing to understand and use atmospheric remote sensing products. All the materials we have used in our workshops as well as our educational materials and case studies are available at http://arset.gsfc.nasa.gov

  11. Unsupervised Trajectory Segmentation for Surgical Gesture Recognition in Robotic Training.

    Science.gov (United States)

    Despinoy, Fabien; Bouget, David; Forestier, Germain; Penet, Cedric; Zemiti, Nabil; Poignet, Philippe; Jannin, Pierre

    2016-06-01

    Dexterity and procedural knowledge are two critical skills that surgeons need to master to perform accurate and safe surgical interventions. However, current training systems do not allow us to provide an in-depth analysis of surgical gestures to precisely assess these skills. Our objective is to develop a method for the automatic and quantitative assessment of surgical gestures. To reach this goal, we propose a new unsupervised algorithm that can automatically segment kinematic data from robotic training sessions. Without relying on any prior information or model, this algorithm detects critical points in the kinematic data that define relevant spatio-temporal segments. Based on the association of these segments, we obtain an accurate recognition of the gestures involved in the surgical training task. We, then, perform an advanced analysis and assess our algorithm using datasets recorded during real expert training sessions. After comparing our approach with the manual annotations of the surgical gestures, we observe 97.4% accuracy for the learning purpose and an average matching score of 81.9% for the fully automated gesture recognition process. Our results show that trainees workflow can be followed and surgical gestures may be automatically evaluated according to an expert database. This approach tends toward improving training efficiency by minimizing the learning curve.

  12. Supervised Learning of Two-Layer Perceptron under the Existence of External Noise — Learning Curve of Boolean Functions of Two Variables in Tree-Like Architecture —

    Science.gov (United States)

    Uezu, Tatsuya; Kiyokawa, Shuji

    2016-06-01

    We investigate the supervised batch learning of Boolean functions expressed by a two-layer perceptron with a tree-like structure. We adopt continuous weights (spherical model) and the Gibbs algorithm. We study the Parity and And machines and two types of noise, input and output noise, together with the noiseless case. We assume that only the teacher suffers from noise. By using the replica method, we derive the saddle point equations for order parameters under the replica symmetric (RS) ansatz. We study the critical value αC of the loading rate α above which the learning phase exists for cases with and without noise. We find that αC is nonzero for the Parity machine, while it is zero for the And machine. We derive the exponents barβ of order parameters expressed as (α - α C)bar{β} when α is near to αC. Furthermore, in the Parity machine, when noise exists, we find a spin glass solution, in which the overlap between the teacher and student vectors is zero but that between student vectors is nonzero. We perform Markov chain Monte Carlo simulations by simulated annealing and also by exchange Monte Carlo simulations in both machines. In the Parity machine, we study the de Almeida-Thouless stability, and by comparing theoretical and numerical results, we find that there exist parameter regions where the RS solution is unstable, and that the spin glass solution is metastable or unstable. We also study asymptotic learning behavior for large α and derive the exponents hat{β } of order parameters expressed as α - hat{β } when α is large in both machines. By simulated annealing simulations, we confirm these results and conclude that learning takes place for the input noise case with any noise amplitude and for the output noise case when the probability that the teacher's output is reversed is less than one-half.

  13. 骨科入院护理流程再造的学习曲线分析%Learning curve research on redesign of orthopedic admission nursing procedure

    Institute of Scientific and Technical Information of China (English)

    张银平; 黄桂玲; 汪祝莎; 王雅丽

    2014-01-01

    Objective To explore the principles of learning curve on redesign of orthopedic admission nursing procedure in order to provide reference to promote the overall nursing procedure .Methods A total of 250 cases after redesign of orthopedic admission nursing procedure were analyzed .These cases covered the stage from the beginning to the matured stage .Every 50 cases were taken as a group and a phase of learning curve . The admission time and satisfaction score were compared among the five different phases ( groups ) .The linear regression technique was employed to research the learning curve and the effect of admission time on the patients 'satisfaction.Results The mean admission time in each group was (27.47 ±3.64) min in Group A, (23.86 ± 1.95)min in Group B, (21.84 ±2.09)min in Group C, (21.74 ±1.83)min in Group D, and (21.85 ±1.79) min in Group E, respectively.The scores of patients'satisfaction in each group were (95.32 ±1.57)min in Group A, (97.44 ±0.95)min in Group B, (98.78 ±0.51)min in Group C, (99.00 ±0.35)min in Group D, and (98.96 ±0.35) min in Group E, respectively.The differences were significant (P 0.05).The learning curve (R2 =0.747,F=289.389,P<0.05) of redesign of orthopedic admission nursing procedure showed that there was linear regression relationship between the admission time (R2 =0.669,F=500.532,P<0.05) and patients'satisfaction.Conclusions The redesign of orthopedic admission nursing procedure is characterized by the learning curve , which the first 100 cases are in the learning stage and after 100 cases is the matured stage .The redesign of orthopedic admission nursing procedure can significantly decrease the admission time and is benefit to establish “the good first impression” and the improvement of the patients'satisfaction.%目的:探讨骨科入院护理流程再造的学习曲线规律,为全面推进骨科护理流程再造提供参考。方法回顾性分析实施入院护理流程再造后250例入院患者的临

  14. Do We Need to Clamp the Renal Hilum Liberally during the Initial Phase of the Learning Curve of Robot-Assisted Nephron-Sparing Surgery?

    Directory of Open Access Journals (Sweden)

    Ömer Acar

    2014-01-01

    Full Text Available Objective. We aimed to compare the results of our initial robot-assisted nephron-sparing surgeries (RANSS performed with or without hilar clamping. Material and Method. Charts of the initial RANSSs (n=44, which were performed by a single surgeon, were retrospectively reviewed. R.E.N.A.L. nephrometry system, modified Clavien classification, and M.D.R.D. equation were used to record tumoral complexity, complications, and estimated glomerular filtration rate (eGFR, respectively. Outcomes of the clamped (group 1, n=14 versus off-clamp (group 2, n=30 RANSSs were compared. Results. The difference between the two groups was insignificant regarding mean patient age, mean tumor size, and mean R.E.N.A.L. nephrometry score. Mean operative time, mean estimated blood loss amount, and mean length of hospitalization were similar between groups. A total of 4 patients in each group suffered 11 Clavien grade ≥2 complications early postoperatively. Open conversion rates were similar. The difference between the 2 groups in terms of the mean postoperative change in eGFR was insignificant. We did not encounter any local recurrence after a mean follow-up of 18.9 months. Conclusions. Creating warm-ischemic conditions during RANSS should not be a liberal decision, even in the initial phases of the learning curve for a highly experienced open surgeon.

  15. 基于学习遗忘曲线模型的员工生产率研究%Study on Worker Productivity with Learn Forget Curve Model

    Institute of Scientific and Technical Information of China (English)

    黄宇菲; 汪应洛

    2011-01-01

    基于学习遗忘曲线模型,研究劳动密集型产业的员工生产率.在将该模型扩展到多周期的基础上,探讨了劳动技能培训与巩固、短期雇佣与长期雇佣等对员工生产率的影响.此外,在考虑发生停产的情况下,分析了不同的人力资源管理策略对员工生产率的影响.研究结果为企业人力资源管理提供了理论依据和参考,并为企业保持较高的员工生产率提供了解决思路.%Based on LFCM (learn forget curve model), this paper studies the worker productivity in labor-intense industry. By extending the original LFCM to multi-period situation, this paper discusses the effects of skill training, long-term and short-term employment on worker productivity. Besides, under the situation of temporary production stop, it invastigates how different human resource management policies influence worker productivity. The conclusions from this research may offer theoretical support and solutions for human resource management to maintain worker productivity.

  16. Learning styles and the prospective ophthalmologist.

    Science.gov (United States)

    Modi, Neil; Williams, Olayinka; Swampillai, Andrew J; Waqar, Salman; Park, Jonathan; Kersey, Thomas L; Sleep, Tamsin

    2015-04-01

    Understanding the learning styles of individual trainees may enable trainers to tailor an educational program and optimise learning. Surgical trainees have previously been shown to demonstrate a tendency towards particular learning styles. We seek to clarify the relationship between learning style and learned surgical performance using a simulator, prior to surgical training. The Kolb Learning Style Inventory was administered to a group of thirty junior doctors. Participants were then asked to perform a series of tasks using the EyeSi virtual reality cataract surgery simulator (VR Magic, Mannheim, Germany). All completed a standard introductory programme to eliminate learning curve. They then undertook four attempts of level 4 forceps module binocularly. Total score, odometer movement (mm), corneal area injured (mm(2)), lens area injured (mm(2)) and total time taken (seconds) recorded. Mean age was 31.6 years. No significant correlation was found between any learning style and any variable on the EyeSi cataract surgery simulator. There is a predominant learning style amongst surgical residents. There is however no demonstrable learning style that results in a better (or worse) performance on the EyeSi surgery simulator and hence in learning and performing cataract surgery.

  17. LCC: Light Curves Classifier

    Science.gov (United States)

    Vo, Martin

    2017-08-01

    Light Curves Classifier uses data mining and machine learning to obtain and classify desired objects. This task can be accomplished by attributes of light curves or any time series, including shapes, histograms, or variograms, or by other available information about the inspected objects, such as color indices, temperatures, and abundances. After specifying features which describe the objects to be searched, the software trains on a given training sample, and can then be used for unsupervised clustering for visualizing the natural separation of the sample. The package can be also used for automatic tuning parameters of used methods (for example, number of hidden neurons or binning ratio). Trained classifiers can be used for filtering outputs from astronomical databases or data stored locally. The Light Curve Classifier can also be used for simple downloading of light curves and all available information of queried stars. It natively can connect to OgleII, OgleIII, ASAS, CoRoT, Kepler, Catalina and MACHO, and new connectors or descriptors can be implemented. In addition to direct usage of the package and command line UI, the program can be used through a web interface. Users can create jobs for ”training” methods on given objects, querying databases and filtering outputs by trained filters. Preimplemented descriptors, classifier and connectors can be picked by simple clicks and their parameters can be tuned by giving ranges of these values. All combinations are then calculated and the best one is used for creating the filter. Natural separation of the data can be visualized by unsupervised clustering.

  18. The New Keynesian Phillips Curve

    DEFF Research Database (Denmark)

    Ólafsson, Tjörvi

    , learning or state-dependant pricing. The introduction of openeconomy factors into the new Keynesian Phillips curve complicate matters further as it must capture the nexus between price setting, inflation and the exchange rate. This is nevertheless a crucial feature for any model to be used for inflation...... forecasting in a small open economy like Iceland....

  19. The new courses of ethanol production in Brazil: an analysis from learning curves; Os novos rumos da producao de alcool combustivel no Brasil: uma analise a partir de curvas de aprendizagem

    Energy Technology Data Exchange (ETDEWEB)

    Pereira Junior, Amaro Olimpio [Empresa de Pesquisa Energetica (EPE), Brasilia, DF (Brazil); Pereira, Andre Santos [Centre de Recherche sur Environement et Developement (CIRED), Paris (France); Mendonca, Marco Aurelio [Instituto de Pesquisa Economica Aplicada (IPEA), Brasilia, DF (Brazil); Costa, Ricardo Cunha da [Universidade Federal do Rio de Janeiro (PPE/COPPE/UFRJ), RJ (Brazil). Coordenacao do Programa de Pos-Graduacao em Engenharia. Programa de Pos-Graduacao em Planejamento Energetico

    2008-07-01

    PROALCOOL is known internationally as the most successful biofuel promotion program. Prior analysis of the effectiveness of such a program is fundamental to formulation of public policy, not only in the area of energy, but in all sectors of the economy. The article applies learning curve methodology to evaluate the ethanol market in Brazil in order to give an idea about the effort, in terms of investments, required for its advancement. (author)

  20. A novel method of teaching surgical techniques to residents--computerized enhanced visual learning (CEVL) with simulation to certify mastery of training: a model using newborn clamp circumcision.

    Science.gov (United States)

    Smith, Angela; Maizels, Max; Korets, Ruslan; Wiener, John S; Stiener, Michael; Liu, Dennis B; Sutherland, Richard W

    2013-12-01

    To assess the learning process of combining a web-based video of a simulated surgical procedure with a step-by-step checklist of the same procedure in achieving competency of the simulated technique, in this case a newborn clamp circumcision. Fundamental to this particular learning process is immediate mentor step-by-step feedback which specifically follows the procedure's step-by-step checklist. Pediatric residents naïve to newborn circumcision were enrolled (n = 7). A circumcision simulator, instruments, and web access to the learning module were provided. Residents trained independently and then performed two simulations with the mentor. The first simulation was completed with formative scored feedback. The learner then performed a second scored simulation. All learners showed improvement between the first and second simulation (mean 85.3-97.4). All residents achieved competency (96/100 or greater) by the second simulation. On post-procedure surveys, learners demonstrated increased comfort and reduced apprehension in performing the procedure. Combining a web-accessible video of a procedure, a checklist, and a simulator followed by a single mentor session with immediate formative feedback which follows the steps of the checklist is a useful method to teach the simulation technique of circumcision. We plan to study if this paradigm is transferable to clinical circumcision. Copyright © 2013 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

  1. A pilot program to improve nursing and surgical intern collaboration: Lessons learned from a mixed-methods study.

    Science.gov (United States)

    Raparla, Neha; Davis, Diane; Shumaker, Daria; Kumar, Anagha; Hafiz, Shabnam; Sava, Jack; Adams, Katie; Fitzgibbons, Shimae C

    2017-02-01

    Inter-professional collaboration is an integral component of a successful healthcare team. We sought to evaluate the impact of nursing student participation in a one-day intensive inter-professional education (IPE) training session with surgical interns on participant attitudes toward inter-professional collaboration. Following IRB approval, pre and post IPE session survey responses were compared to determine the impact on participant attitudes toward inter-professional collaboration. Pre and post session semi-structured interviews were transcribed and analyzed to identify relevant themes. Surgical interns (n = 38) more than nursing students (n = 11), demonstrated a measurable improvement in attitude towards 'collaboration and shared education' (interns: median score pre = 26, post = 28, p = 0.0004; nursing student: median score pre = 27, post = 28, p = 0.02). Qualitative analysis of interviews identified major themes that supplemented this finding. An eight hour, one day IPE session has a positive impact on collaborative attitudes and supports the case for increased inter-professional education amongst interns and nursing students. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Organic bench model to complement the teaching and learning on basic surgical skills Modelo de bancada orgânico para complementar o ensino-aprendizagem de habilidades cirúrgicas básicas

    OpenAIRE

    Rafael Denadai; Luís Ricardo Martinhão Souto

    2012-01-01

    PURPOSE: To propose an organic bench model made with fruits/vegetables as an alternative to complement the arsenal of simulators used in the teaching and learning of basic surgical skills during medical graduation and education. METHODS: They were described the training strategies, through the use of fruits (or vegetables) to the learning of different techniques of incision, sutures, biopsies and basic principles of reconstruction. The preparation of bench model, the processes of skill acquis...

  3. Using optimization models to demonstrate the need for structural changes in training programs for surgical medical residents.

    Science.gov (United States)

    Turner, Jonathan; Kim, Kibaek; Mehrotra, Sanjay; DaRosa, Debra A; Daskin, Mark S; Rodriguez, Heron E

    2013-09-01

    The primary goal of a residency program is to prepare trainees for unsupervised care. Duty hour restrictions imposed throughout the prior decade require that residents work significantly fewer hours. Moreover, various stakeholders (e.g. the hospital, mentors, other residents, educators, and patients) require them to prioritize very different activities, often conflicting with their learning goals. Surgical residents' learning goals include providing continuity throughout a patient's pre-, peri-, and post-operative care as well as achieving sufficient surgical experience levels in various procedure types and participating in various formal educational activities, among other things. To complicate matters, senior residents often compete with other residents for surgical experience. This paper features experiments using an optimization model and a real dataset. The experiments test the viability of achieving the above goals at a major academic center using existing models of delivering medical education and training to surgical residents. It develops a detailed multi-objective, two-stage stochastic optimization model with anticipatory capabilities solved over a rolling time horizon. A novel feature of the models is the incorporation of learning curve theory in the objection function. Using a deterministic version of the model, we identify bounds on the achievement of learning goals under existing training paradigms. The computational results highlight the structural problems in the current surgical resident educational system. These results further corroborate earlier findings and suggest an educational system redesign is necessary for surgical medical residents.

  4. Learning curve of transumbilical single-site laparoscopic cholecystectomy with conventional devices%常规器械经脐腹腔镜胆囊切除术学习曲线分析

    Institute of Scientific and Technical Information of China (English)

    吴庆华; 包皙婷; 孔雷; 刘玉祥; 陈勇; 王赭; 项明

    2016-01-01

    目的:评估常规器械经脐单部位腹腔镜胆囊切除术(transumbilical single-site laparoscopic cholecystectomy, TUSSLC)的阶段疗效,分析其学习曲线。方法:回顾性分析2014年3月至2015年1月笔者应用自创的常规器械“两trocar两切口”TUSSLC 100例。按手术顺序将病例分为6组,即A组、B组、C组、D组、E组各15例与F组25例。比较各组在性别、年龄、体质量指数、病种及手术时间、术中失血量、手术并发症、术后住院时间方面的差异。绘制学习曲线。结果:各组在性别、年龄、体质量指数及病种方面无统计学差异(P>0.05)。所有病例均顺利完成常规器械TUS-SLC,无术中中转,无术后腹腔内出血、胆道损伤等并发症发生。A组手术时间(59.7±16.7) min大于其余各组(P<0.05)。各组在术中失血量、术后住院时间方面无统计学差异(P>0.05)。术后随访6~9个月,随访率100%。无腹痛、发热、黄疸等术后胆道并发症发生,病人对脐部切口恢复的美容效果均满意。结论:常规器械TUSSLC安全可行,学习期估计为11例。掌握此术式特有的操作要点,可能有助于进一步缩短其学习期。%Objective To investigate the effect and learning curve of transumbilical single-site laparoscopic chole-cystectomy with conventional devices. Methods A retrospective analysis was made to 100 enrolled patients undergoing transumbilical single-site laparoscopic cholecystectomy with conventional devices by a self-created method so called “sin-gle site two trocars and two incisions” from Mar 2014 to Jan 2015. These consecutive cases were divided into six groups as group A (n=15), group B (n=15), group C (n=15), group D (n=15), group E (n=15) and group F (n=25). Demographic da-ta such as gender, age, body mass index and disease entity and surgical data such as operating time, operative blood loss, complications and postoperative hospital stay among the

  5. Ahmed glaucoma valve implant: surgical technique and complications

    Directory of Open Access Journals (Sweden)

    Riva I

    2017-02-01

    Full Text Available Ivano Riva,1 Gloria Roberti,1 Francesco Oddone,1 Anastasios GP Konstas,2 Luciano Quaranta3 1IRCCS “Fondazione GB Bietti per l’Oftalmologia”, Rome, Italy; 21st University Department of Ophthalmology, Glaucoma Unit, AHEPA Hospital, Thessaloniki, Greece; 3Department of Medical and Surgical Specialties, Section of Ophthalmology, University of Brescia, Brescia, Italy Abstract: Implantation of Ahmed glaucoma valve is an effective surgical technique to reduce intraocular pressure in patients affected with glaucoma. While in the past, the use of this device was reserved to glaucoma refractory to multiple filtration surgical procedures, up-to-date mounting experience has encouraged its use also as a primary surgery for selected cases. Implantation of Ahmed glaucoma valve can be challenging for the surgeon, especially in patients who already underwent previous multiple surgeries. Several tips have to be acquired by the surgeon, and a long learning curve is always needed. Although the valve mechanism embedded in the Ahmed glaucoma valve decreases the risk of postoperative hypotony-related complications, it does not avoid the need of a careful follow-up. Complications related to this type of surgery include early and late postoperative hypotony, excessive capsule fibrosis around the plate, erosion of the tube or plate edge, and very rarely infection. The aim of this review is to describe surgical technique for Ahmed glaucoma valve implantation and to report related complications. Keywords: glaucoma, surgical technique, glaucoma drainage devices, Ahmed glaucoma valve, complications

  6. Multiphasic growth curve analysis.

    NARCIS (Netherlands)

    Koops, W.J.

    1986-01-01

    Application of a multiphasic growth curve is demonstrated with 4 data sets, adopted from literature. The growth curve used is a summation of n logistic growth functions. Human height growth curves of this type are known as "double logistic" (n = 2) and "triple logistic" (n = 3) growth curves (Bock

  7. Rational points on elliptic curves

    CERN Document Server

    Silverman, Joseph H

    2015-01-01

    The theory of elliptic curves involves a pleasing blend of algebra, geometry, analysis, and number theory. This book stresses this interplay as it develops the basic theory, thereby providing an opportunity for advanced undergraduates to appreciate the unity of modern mathematics. At the same time, every effort has been made to use only methods and results commonly included in the undergraduate curriculum. This accessibility, the informal writing style, and a wealth of exercises make Rational Points on Elliptic Curves an ideal introduction for students at all levels who are interested in learning about Diophantine equations and arithmetic geometry. Most concretely, an elliptic curve is the set of zeroes of a cubic polynomial in two variables. If the polynomial has rational coefficients, then one can ask for a description of those zeroes whose coordinates are either integers or rational numbers. It is this number theoretic question that is the main subject of this book. Topics covered include the geometry and ...

  8. The New Keynesian Phillips Curve

    DEFF Research Database (Denmark)

    Ólafsson, Tjörvi

    This paper provides a survey on the recent literature on the new Keynesian Phillips curve: the controversies surrounding its microfoundation and estimation, the approaches that have been tried to improve its empirical fit and the challenges it faces adapting to the open-economy framework. The new...... Keynesian Phillips curve has been severely criticized for poor empirical dynamics. Suggested improvements involve making some adjustments to the standard sticky price framework, e.g. introducing backwardness and real rigidities, or abandoning the sticky price model and relying on models of inattentiveness......, learning or state-dependant pricing. The introduction of openeconomy factors into the new Keynesian Phillips curve complicate matters further as it must capture the nexus between price setting, inflation and the exchange rate. This is nevertheless a crucial feature for any model to be used for inflation...

  9. Future technological and economic performance of IGCC and FT production facilities with and without CO2 capture: Combining component based learning curve and bottom-up analysis

    NARCIS (Netherlands)

    Knoope, M.M.J.; Meerman, J.C.; Ramirez, C.A.; Faaij, A.P.C.

    2013-01-01

    This study aims to investigate the technological and economic prospects of integrated gasification facilities for power (IGCC) and Fischer–Tropsch (FT) liquid production with and without CCS over time. For this purpose, a component based experience curve was constructed and applied to identify the p

  10. Longitudinal Examination of Procrastination and Anxiety, and Their Relation to Self-Efficacy for Self- Regulated Learning: Latent Growth Curve Modeling

    Science.gov (United States)

    Yerdelen, Sündüs; McCaffrey, Adam; Klassen, Robert M.

    2016-01-01

    This study investigated the longitudinal association between students' anxiety and procrastination and the relation of self-efficacy for self-regulation to these constructs. Latent Growth Curve Modeling was used to analyze data gathered from 182 undergraduate students (134 female, 48 male) at 4 times during a semester. Our results showed that…

  11. No surgical innovation without evaluation: the IDEAL recommendations.

    Science.gov (United States)

    McCulloch, Peter; Altman, Douglas G; Campbell, W Bruce; Flum, David R; Glasziou, Paul; Marshall, John C; Nicholl, Jon; Aronson, Jeffrey K; Barkun, Jeffrey S; Blazeby, Jane M; Boutron, Isabell C; Campbell, W Bruce; Clavien, Pierre-Alain; Cook, Jonathan A; Ergina, Patrick L; Feldman, Liane S; Flum, David R; Maddern, Guy J; Nicholl, Jon; Reeves, Bournaby C; Seiler, Christoph M; Strasberg, Steven M; Meakins, Jonathan L; Ashby, Deborah; Black, Nick; Bunker, John; Burton, Martin; Campbell, Marion; Chalkidou, Kalipso; Chalmers, Iain; de Leval, Marc; Deeks, Jon; Ergina, Patrick L; Grant, Adrian; Gray, Muir; Greenhalgh, Roger; Jenicek, Milos; Kehoe, Sean; Lilford, Richard; Littlejohns, Peter; Loke, Yoon; Madhock, Rajan; McPherson, Kim; Meakins, Jonathan; Rothwell, Peter; Summerskill, Bill; Taggart, David; Tekkis, Parris; Thompson, Matthew; Treasure, Tom; Trohler, Ulrich; Vandenbroucke, Jan

    2009-09-26

    Surgery and other invasive therapies are complex interventions, the assessment of which is challenged by factors that depend on operator, team, and setting, such as learning curves, quality variations, and perception of equipoise. We propose recommendations for the assessment of surgery based on a five-stage description of the surgical development process. We also encourage the widespread use of prospective databases and registries. Reports of new techniques should be registered as a professional duty, anonymously if necessary when outcomes are adverse. Case series studies should be replaced by prospective development studies for early technical modifications and by prospective research databases for later pre-trial evaluation. Protocols for these studies should be registered publicly. Statistical process control techniques can be useful in both early and late assessment. Randomised trials should be used whenever possible to investigate efficacy, but adequate pre-trial data are essential to allow power calculations, clarify the definition and indications of the intervention, and develop quality measures. Difficulties in doing randomised clinical trials should be addressed by measures to evaluate learning curves and alleviate equipoise problems. Alternative prospective designs, such as interrupted time series studies, should be used when randomised trials are not feasible. Established procedures should be monitored with prospective databases to analyse outcome variations and to identify late and rare events. Achievement of improved design, conduct, and reporting of surgical research will need concerted action by editors, funders of health care and research, regulatory bodies, and professional societies.

  12. Spinal curves (image)

    Science.gov (United States)

    There are four natural curves in the spinal column. The cervical, thoracic, lumbar, and sacral curvature. The curves, along with the intervertebral disks, help to absorb and distribute stresses that occur from everyday activities such as walking or from ...

  13. Contractibility of curves

    Directory of Open Access Journals (Sweden)

    Janusz Charatonik

    1991-11-01

    Full Text Available Results concerning contractibility of curves (equivalently: of dendroids are collected and discussed in the paper. Interrelations tetween various conditions which are either sufficient or necessary for a curve to be contractible are studied.

  14. Parametrizing Algebraic Curves

    OpenAIRE

    Lemmermeyer, Franz

    2011-01-01

    We present the technique of parametrization of plane algebraic curves from a number theorist's point of view and present Kapferer's simple and beautiful (but little known) proof that nonsingular curves of degree > 2 cannot be parametrized by rational functions.

  15. 基于学习曲线的中国光伏发电成本发展趋势分析%Analysis of Cost Development Trend of Photovoltaic Power Generation in China Based on Learning Curve

    Institute of Scientific and Technical Information of China (English)

    隋礼辉

    2012-01-01

    This paper presents the development trend of photovoltaic power generation in China. Based on the learning curve model, constant learning rates and stage learning rates are adopted to analyze the development trend of photovoltaic power generation unit cost. And the learning cost of PV power generation achieved commercial operation is estimated. Then it predicts that the cost of PV power generation in 2020 is expected to match the traditional fossil fuels and will be realized the large-scale commercial operation stage.%介绍了我国光伏发电的发展情况,以学习曲线模型为原理,分别采用恒定学习率与分阶段学习率分析了未来我国10年光伏发电单位成本发展趋势,并估算了光伏发电实现商业化运作所需的学习成本,预测在2020年左右我国光伏发电成本有望与传统化石能源相持平,进而步入大规模商业化运作阶段.

  16. Justice and Surgical Innovation: The Case of Robotic Prostatectomy.

    Science.gov (United States)

    Hutchison, Katrina; Johnson, Jane; Carter, Drew

    2016-09-01

    Surgical innovation promises improvements in healthcare, but it also raises ethical issues including risks of harm to patients, conflicts of interest and increased injustice in access to health care. In this article, we focus on risks of injustice, and use a case study of robotic prostatectomy to identify features of surgical innovation that risk introducing or exacerbating injustices. Interpreting justice as encompassing matters of both efficiency and equity, we first examine questions relating to government decisions about whether to publicly fund access to innovative treatments. Here the case of robotic prostatectomy exemplifies the difficulty of accommodating healthcare priorities such as improving the health of marginalized groups. It also illustrates challenges with estimating the likely long-term costs and benefits of a new intervention, the difficulty of comparing outcomes of an innovative treatment to those of established treatments, and the further complexity associated with patient and surgeon preferences. Once the decision has been made to fund a new procedure, separate issues of justice arise at the level of providing care to individual patients. Here, the case of robotic prostatectomy exemplifies how features of surgical innovation, such as surgeon learning curves and the need for an adequate volume of cases at a treatment centre, can exacerbate injustices associated with treatment cost and the logistics of travelling for treatment. Drawing on our analysis, we conclude by making a number of recommendations for the just introduction of surgical innovations.

  17. Halstedian technique revisited. Innovations in teaching surgical skills.

    Science.gov (United States)

    Barnes, R W; Lang, N P; Whiteside, M F

    1989-07-01

    This paper reviews the laboratory models used to teach fundamental surgical skills in our general surgery residency. The laboratory modules allow supervision and self-instruction, practice, and videotape monitoring of the following techniques: skin incision, suturing, knot tying, hemostasis, vascular anastomosis, and intestinal anastomosis. Pigs' feet simulate human skin for exercises in skin incision, lesion excision, suturing, and basic plastic surgical techniques. Latex tubing and penrose drains allow experience in suturing, knot tying, and hemostasis. Polytetrafluoroethylene vascular prostheses permit quantification of the precision of needle passage and suturing by measurement of leakage of water through a vascular anastomosis. Reconstituted, lyophilized, irradiated bovine arteries and ileum provide models of biologic tissue for creating handsewn vascular anastomoses and sutured or stapled gastrointestinal anastomoses. A headlamp videocamera allows unobstructive recording of the resident's technical performance and provides subsequent visual feedback for self-improvement when compared to reference instructional videotapes. We feel that these innovations may enhance surgical dexterity of residents without the need for animal sacrifice. Our goal is to foreshorten the learning curve for basic surgical skills and improve performance in the clinical operating room.

  18. ECM using Edwards curves

    DEFF Research Database (Denmark)

    Bernstein, Daniel J.; Birkner, Peter; Lange, Tanja;

    2013-01-01

    This paper introduces EECM-MPFQ, a fast implementation of the elliptic-curve method of factoring integers. EECM-MPFQ uses fewer modular multiplications than the well-known GMP-ECM software, takes less time than GMP-ECM, and finds more primes than GMP-ECM. The main improvements above the modular......-arithmetic level are as follows: (1) use Edwards curves instead of Montgomery curves; (2) use extended Edwards coordinates; (3) use signed-sliding-window addition-subtraction chains; (4) batch primes to increase the window size; (5) choose curves with small parameters and base points; (6) choose curves with large...

  19. Pencils on real curves

    CERN Document Server

    Coppens, Marc

    2011-01-01

    We consider coverings of real algebraic curves to real rational algebraic curves. We show the existence of such coverings having prescribed topological degree on the real locus. From those existence results we prove some results on Brill-Noether Theory for pencils on real curves. For coverings having topological degree 0 we introduce the covering number k and we prove the existence of coverings of degree 4 with prescribed covering number.

  20. JUMPING THE CURVE

    Directory of Open Access Journals (Sweden)

    René Pellissier

    2012-01-01

    Full Text Available This paper explores the notion ofjump ing the curve,following from Handy 's S-curve onto a new curve with new rules policies and procedures. . It claims that the curve does not generally lie in wait but has to be invented by leadership. The focus of this paper is the identification (mathematically and inferentially ofthat point in time, known as the cusp in catastrophe theory, when it is time to change - pro-actively, pre-actively or reactively. These three scenarios are addressed separately and discussed in terms ofthe relevance ofeach.

  1. Simulating Supernova Light Curves

    Energy Technology Data Exchange (ETDEWEB)

    Even, Wesley Paul [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dolence, Joshua C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-05

    This report discusses supernova light simulations. A brief review of supernovae, basics of supernova light curves, simulation tools used at LANL, and supernova results are included. Further, it happens that many of the same methods used to generate simulated supernova light curves can also be used to model the emission from fireballs generated by explosions in the earth’s atmosphere.

  2. Tempo curves considered harmful

    NARCIS (Netherlands)

    Desain, P.; Honing, H.

    1993-01-01

    In the literature of musicology, computer music research and the psychology of music, timing or tempo measurements are mostly presented in the form of continuous curves. The notion of these tempo curves is dangerous, despite its widespread use, because it lulls its users into the false impression th

  3. Pairings on hyperelliptic curves

    CERN Document Server

    Balakrishnan, Jennifer; Chisholm, Sarah; Eisentraeger, Kirsten; Stange, Katherine; Teske, Edlyn

    2009-01-01

    We assemble and reorganize the recent work in the area of hyperelliptic pairings: We survey the research on constructing hyperelliptic curves suitable for pairing-based cryptography. We also showcase the hyperelliptic pairings proposed to date, and develop a unifying framework. We discuss the techniques used to optimize the pairing computation on hyperelliptic curves, and present many directions for further research.

  4. Retrospectives: Engel Curves

    National Research Council Canada - National Science Library

    Andreas Chai; Alessio Moneta

    2010-01-01

    ..., Professor of Economics, University of Illinois, Chicago, at jpersky@uic.edu jpersky@uic.edu.. Introduction Introduction Engel curves describe how household expenditure on particular goods or Engel curves describe how household expenditure on particular goods or services depends on household income. The name comes from the German st...

  5. Tornado-Shaped Curves

    Science.gov (United States)

    Martínez, Sol Sáez; de la Rosa, Félix Martínez; Rojas, Sergio

    2017-01-01

    In Advanced Calculus, our students wonder if it is possible to graphically represent a tornado by means of a three-dimensional curve. In this paper, we show it is possible by providing the parametric equations of such tornado-shaped curves.

  6. The curve shortening problem

    CERN Document Server

    Chou, Kai-Seng

    2001-01-01

    Although research in curve shortening flow has been very active for nearly 20 years, the results of those efforts have remained scattered throughout the literature. For the first time, The Curve Shortening Problem collects and illuminates those results in a comprehensive, rigorous, and self-contained account of the fundamental results.The authors present a complete treatment of the Gage-Hamilton theorem, a clear, detailed exposition of Grayson''s convexity theorem, a systematic discussion of invariant solutions, applications to the existence of simple closed geodesics on a surface, and a new, almost convexity theorem for the generalized curve shortening problem.Many questions regarding curve shortening remain outstanding. With its careful exposition and complete guide to the literature, The Curve Shortening Problem provides not only an outstanding starting point for graduate students and new investigations, but a superb reference that presents intriguing new results for those already active in the field.

  7. Shortening the learning curve in endoscopic endonasal skull base surgery: a reproducible polymer tumor model for the trans-sphenoidal trans-tubercular approach to retro-infundibular tumors.

    Science.gov (United States)

    Berhouma, Moncef; Baidya, Nishanta B; Ismaïl, Abdelhay A; Zhang, Jun; Ammirati, Mario

    2013-09-01

    Endoscopic endonasal skull base surgery attracts an increasing number of young neurosurgeons. This recent technique requires specific technical skills for the approaches to non-pituitary tumors (expanded endoscopic endonasal surgery). Actual residents' busy schedules carry the risk of compromising their laboratory training by limiting significantly the dedicated time for dissections. To enhance and shorten the learning curve in expanded endoscopic endonasal skull base surgery, we propose a reproducible model based on the implantation of a polymer via an intracranial route to provide a pathological retro-infundibular expansive lesion accessible to a virgin expanded endoscopic endonasal route, avoiding the ethically-debatable need to hundreds of pituitary cases in live patients before acquiring the desired skills. A polymer-based tumor model was implanted in 6 embalmed human heads via a microsurgical right fronto-temporal approach through the carotido-oculomotor cistern to mimic a retro-infundibular tumor. The tumor's position was verified by CT-scan. An endoscopic endonasal trans-sphenoidal trans-tubercular trans-planum approach was then carried out on a virgin route under neuronavigation tracking. Dissection of the tumor model from displaced surrounding neurovascular structures reproduced live surgery's sensations and challenges. Post-implantation CT-scan allowed the pre-removal assessment of the tumor insertion, its relationships as well as naso-sphenoidal anatomy in preparation of the endoscopic approach. Training on easily reproducible retro-infundibular approaches in a context of pathological distorted anatomy provides a unique opportunity to avoid the need for repetitive live surgeries to acquire skills for this kind of rare tumors, and may shorten the learning curve for endoscopic endonasal surgery. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Surgical Training in the Netherlands

    NARCIS (Netherlands)

    Borel Rinkes, I.H.M.; Gouma, D.J.; Hamming, J.F.

    2008-01-01

    Surgical training in the Netherlands has traditionally been characterized by learning on the job under the classic master-trainee doctrine. Over the past decades, it has become regionally organized with intensive structural training courses, and a peer-based quality control system. Recently, the nat

  9. SRHA calibration curve

    Data.gov (United States)

    U.S. Environmental Protection Agency — an UV calibration curve for SRHA quantitation. This dataset is associated with the following publication: Chang, X., and D. Bouchard. Surfactant-Wrapped Multiwalled...

  10. ROBUST DECLINE CURVE ANALYSIS

    Directory of Open Access Journals (Sweden)

    Sutawanir Darwis

    2012-05-01

    Full Text Available Empirical decline curve analysis of oil production data gives reasonable answer in hyperbolic type curves situations; however the methodology has limitations in fitting real historical production data in present of unusual observations due to the effect of the treatment to the well in order to increase production capacity. The development ofrobust least squares offers new possibilities in better fitting production data using declinecurve analysis by down weighting the unusual observations. This paper proposes a robustleast squares fitting lmRobMM approach to estimate the decline rate of daily production data and compares the results with reservoir simulation results. For case study, we usethe oil production data at TBA Field West Java. The results demonstrated that theapproach is suitable for decline curve fitting and offers a new insight in decline curve analysis in the present of unusual observations.

  11. Large Curved Surface Measurement

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The measurement principle of large curved surface through theodolite industry survey system is introduced. Two methods are suggested with respect to the distribution range of curved surface error. The experiments show that the measurement precision can be up to 0.15mm with relative precision of 3×10-5. Finally, something needed paying attention to and the application aspects on theodolite industry survey system are given.

  12. Counting curves on surfaces

    OpenAIRE

    2015-01-01

    In this paper we consider an elementary, and largely unexplored, combinatorial problem in low-dimensional topology. Consider a real 2-dimensional compact surface $S$, and fix a number of points $F$ on its boundary. We ask: how many configurations of disjoint arcs are there on $S$ whose boundary is $F$? We find that this enumerative problem, counting curves on surfaces, has a rich structure. For instance, we show that the curve counts obey an effective recursion, in the general framework of to...

  13. Arithmetic of Shimura curves

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This is the note for a series of lectures that the author gave at the Centre de Recerca Matemtica (CRM), Bellaterra, Barcelona, Spain on October 19–24, 2009. The aim is to give a comprehensive description of some recent work of the author and his students on generalisations of the Gross-Zagier formula, Euler systems on Shimura curves, and rational points on elliptic curves.

  14. Highly curved microchannel plates

    Science.gov (United States)

    Siegmund, O. H. W.; Cully, S.; Warren, J.; Gaines, G. A.; Priedhorsky, W.; Bloch, J.

    1990-01-01

    Several spherically curved microchannel plate (MCP) stack configurations were studied as part of an ongoing astrophysical detector development program, and as part of the development of the ALEXIS satellite payload. MCP pairs with surface radii of curvature as small as 7 cm, and diameters up to 46 mm have been evaluated. The experiments show that the gain (greater than 1.5 x 10 exp 7) and background characteristics (about 0.5 events/sq cm per sec) of highly curved MCP stacks are in general equivalent to the performance achieved with flat MCP stacks of similar configuration. However, gain variations across the curved MCP's due to variations in the channel length to diameter ratio are observed. The overall pulse height distribution of a highly curved surface MCP stack (greater than 50 percent FWHM) is thus broader than its flat counterpart (less than 30 percent). Preconditioning of curved MCP stacks gives comparable results to flat MCP stacks, but it also decreases the overall gain variations. Flat fields of curved MCP stacks have the same general characteristics as flat MCP stacks.

  15. Surgical education and training in an outer metropolitan hospital: a qualitative study of surgical trainers and trainees.

    Science.gov (United States)

    Nestel, Debra; Harlim, Jennifer; Bryant, Melanie; Rampersad, Rajay; Hunter-Smith, David; Spychal, Bob

    2016-07-14

    The landscape of surgical training is changing. The anticipated increase in the numbers of surgical trainees and the shift to competency-based surgical training places pressures on an already stretched health service. With these pressures in mind, we explored trainers' and trainees' experiences of surgical training in a less traditional rotation, an outer metropolitan hospital. We considered practice-based learning theories to make meaning of surgical training in this setting, in particular Actor-network theory. We adopted a qualitative approach and purposively sampled surgical trainers and trainees to participate in individual interviews and focus groups respectively. Transcripts were made and thematically analysed. Institutional human research ethics approval was obtained. Four surgical trainers and fourteen trainees participated. Almost without exception, participants' report training needs to be well met. Emergent inter-related themes were: learning as social activity; learning and programmatic factors; learning and physical infrastructure; and, learning and organizational structure. This outer metropolitan hospital is suited to the provision of surgical training with the current rotational system for trainees. The setting offers experiences that enable consolidation of learning providing a rich and varied overall surgical training program. Although relational elements of learning were paramount they occurred within a complex environment. Actor-network theory was used to give meaning to emergent themes acknowledging that actors (both people and objects) and their interactions combine to influence training quality, shifting the focus of responsibility for learning away from individuals to the complex interactions in which they work and learn.

  16. Endoluminal surgical triangulation 2.0: A new flexible surgical robot. Preliminary pre-clinical results with colonic submucosal dissection.

    Science.gov (United States)

    Légner, András; Diana, Michele; Halvax, Péter; Liu, Yu-Yin; Zorn, Lucile; Zanne, Philippe; Nageotte, Florent; De Mathelin, Michel; Dallemagne, Bernard; Marescaux, Jacques

    2017-05-03

    Complex intraluminal surgical interventions of the gastrointestinal tract are challenging due to the limitation of existing instruments. Our group has developed a master-slave robotic flexible endoscopic platform that provides instrument triangulation in an endoluminal environment. Colonic endoscopic submucosal dissections (ESD) were carried out in eight pigs. The robot was introduced transanally. A combination of adapted tele-operated instruments was used. Specimens were inspected and measured. Out of 18 ESDs in total, 12 were successfully completed. Among the completed procedures, two perforations and one system failure occurred and were managed intraoperatively. There was no major bleeding. Mean size of the removed specimens was 18.2 ± 9.8 cm(2) and mean total procedure time was 73 ± 35.5 min. Experimental colorectal ESDs using the flexible surgical robot were feasible and reflected a short learning curve. After some technical improvements the system might allow for a wider adoption of complex endoluminal surgical procedures. Copyright © 2017 John Wiley & Sons, Ltd.

  17. Approximation by planar elastic curves

    DEFF Research Database (Denmark)

    Brander, David; Gravesen, Jens; Nørbjerg, Toke Bjerge

    2016-01-01

    We give an algorithm for approximating a given plane curve segment by a planar elastic curve. The method depends on an analytic representation of the space of elastic curve segments, together with a geometric method for obtaining a good initial guess for the approximating curve. A gradient......-driven optimization is then used to find the approximating elastic curve....

  18. The learning curve of endoscopic thoracic sympathectomy for treatment of primary Hyperhidrosis%胸腔镜下交感神经切除术治疗手汗症的学习曲线

    Institute of Scientific and Technical Information of China (English)

    吴伟彬; 谷力加; 黄邵洪; 张健; 廖洪映; 李昀; 蔡松旺; 陈惠国; 王翠苹; 李小军

    2012-01-01

    Objective: To evaluate the learning curve of endoscopic thoracic sympathectomy ( ETC ) for treatment of primary hyperhidrosis. Methods: Sixty patients with primary hyperhidrosis were treated by endoscopic tho -racic sympathectomy by a single group of surgeons. The patients were divided into three group ( Group A, B and C , n = 20 ) according to operative sequence. The operative duration ( Dl ) , the duration between ganglia identifi -cation and resection ( D2) , the length of postoperative hospital stay , and complications were recorded. Dl and D2 were chose as the main indexes of learning curve. Results:Dl in Group A (76 ±17) min was significantly longer than that in Group B (33 ±7) min or Group C (48 ±11) min, and so was D2 (43 ±8) min vs (33 ±7) or (33 ± 8 ) min, respectively , P < 0. 01. There was no significant difference in other indexes revealed . Conclusion: The practice of ETS in 20 cases provided sufficient improvement in treatment of primary hyperhidrosis according to the learning curve.%目的:探讨胸腔镜下交感神经切除术治疗手汗症的学习曲线.方法:于电视胸腔镜下采用双侧T3~T4交感神经链切除术治疗原发性手足多汗症患者60例,均由同一组手术医师完成手术,按手术先后时间将其分为A、B、C 3组各20例,对比各组手术时间、从辨别到切除神经节的时间、术后平均住院时间及术后并发症发生率等指标的差异,以手术时间、从辨别到切除神经节的时间为主要的学习曲线指标.结果:A组手术时间(76±17)min,显著长于B组的(50±11)min和C组的(48±11)min(P均<0.01),A组辨别和切除神经节的时间(43±8)min比B组(33±7)min和C组(33±8)min长(P均<0.01).其余指标各组比较差异无统计学意义.结论:通过约20例的手术实践,电视胸腔镜下行T3~T4交感神经链切除术治疗原发性手足多汗症可达到熟练掌握的程度.

  19. 椎间盘镜治疗腰椎间盘突出症初100例的学习曲线及经验%Microendoscopic lumbar discectomy:a learning curve and experience of first 100 cases

    Institute of Scientific and Technical Information of China (English)

    刘丰平; 赵红卫; 陈海丹; 罗茗刈

    2015-01-01

    Objective To analyze the learning curve of microendoscopic lumbar discectomy (MED) and summarize the operative experience. Methods From July 2010 to March 2012, the first 100 patients with single level lumbar disc herniation managed with MED were divided into chronological groups (A, B, C and D), 30 patients in group A, B, C and 10 patients in group D. The comparsons were conducted in terms of operative time , estimated blood loss , number of cases with transition from MED to open surgey or for reoperation , rate of complications and postoperative efficacy. Results The mean operative time and the mean estimated blood loss in each group was valuated respectively. In group A , the operative time and estimated blood loss were significantly decreased as compared with those in group B, C and D respectively (P 0.05). There were 6 complications in group A, 1 complication in group B and C respectively and no complication in group D. The leg pain visual analogue scale and Oswestry disability index at the first month and the twelfth month postoperatively were all improved respectively as compared with those preoperatively (P < 0.01). Conclusion The learning curve of microendoscopic lumbar discectomy generally may reach the plateau when about 30 cases are operated on. The key procedure to pass over the learning curve includes puncture and location , flavectomy , anatomy mark identification, and precaution of damage in dural sac.%目的:分析椎间盘镜下腰椎间盘髓核摘除术的学习曲线,并对其手术经验进行总结。方法:2010年7月至2012年3月,通过椎间盘镜治疗最初100例单节段腰椎间盘突出症,按时间系列先后顺序分为4组(A、B、C、D组),前3组每组30例,D组10例,对各组手术中手术时间、手术出血、中转开放或再次手术、并发症、术后疗效进行比较和分析。结果:4组平均每例手术时间、出血量分别被统计,其中A组手术时间和出血量较B、C

  20. Emotions in veterinary surgical students

    DEFF Research Database (Denmark)

    Langebæk, Rikke; Eika, Berit; Pedersen, Lene Tanggaard

    2012-01-01

    A surgical educational environment is potentially stressful and can negatively affect students' learning. The aim of the present study was to investigate the emotions experienced by veterinary students in relation to their first encounter with live-animal surgery and to identify possible sources...... of positive and negative emotions, respectively. During a Basic Surgical Skills course, 155 veterinary fourth-year students completed a survey. Of these, 26 students additionally participated in individual semi-structured interviews. The results of the study show that students often experienced a combination...

  1. Moduli of Trigonal Curves

    CERN Document Server

    Stankova-Frenkel, Z E

    1997-01-01

    We study the moduli of trigonal curves. We establish the exact upper bound of ${36(g+1)}/(5g+1)$ for the slope of trigonal fibrations. Here, the slope of any fibration $X\\to B$ of stable curves with smooth general member is the ratio Hodge class $\\lambda$ on the moduli space $\\bar{\\mathfrak{M}}_g$ to the base $B$. We associate to a trigonal family $X$ a canonical rank two vector bundle $V$, and show that for Bogomolov-semistable $V$ the slope satisfies the stronger inequality ${\\delta_B}/{\\lambda_B}\\leq 7+{6}/{g}$. We further describe the rational Picard group of the {trigonal} locus $\\bar{\\mathfrak T}_g$ in the moduli space $\\bar{\\mathfrak{M}}_g$ of genus $g$ curves. In the even genus case, we interpret the above Bogomolov semistability condition in terms of the so-called Maroni divisor in $\\bar{\\mathfrak T}_g$.

  2. Power Curve Measurements REWS

    DEFF Research Database (Denmark)

    Gómez Arranz, Paula; Vesth, Allan

    This report describes the power curve measurements carried out on a given wind turbine in a chosen period. The measurements were carried out following the measurement procedure in the draft of IEC 61400-12-1 Ed.2 [1], with some deviations mostly regarding uncertainty calculation. Here, the refere......This report describes the power curve measurements carried out on a given wind turbine in a chosen period. The measurements were carried out following the measurement procedure in the draft of IEC 61400-12-1 Ed.2 [1], with some deviations mostly regarding uncertainty calculation. Here......, the reference wind speed used in the power curve is the equivalent wind speed obtained from lidar measurements at several heights between lower and upper blade tip, in combination with a hub height meteorological mast. The measurements have been performed using DTU’s measurement equipment, the analysis...

  3. Surgical education and the theoretical concept of communities of practice

    Directory of Open Access Journals (Sweden)

    Debra Nestel

    2014-01-01

    Full Text Available Surgical practice is largely learned in the workplace. Changes in health services and education provision have seen a shift from traditional apprenticeship-type learning to competency-based curricula with the workplace remaining the principal site for learning. Sociocultural learning theories offer valuable lenses through which to observe, design for, and analyze workplace-based learning. In this paper, we consider the theoretical concept of communities of practice in surgery. We describe notions of legitimate peripheral participation and development of professional identity. We highlight the benefits that communities of practice bring to surgical training, as well as the limitations. By understanding community of practice theory as applied to the surgical workplace and the factors that both drive and impede its development, surgical trainers may improve the learning environment, enhancing the attainment of competencies by surgical trainees.

  4. Algebraic curves and cryptography

    CERN Document Server

    Murty, V Kumar

    2010-01-01

    It is by now a well-known paradigm that public-key cryptosystems can be built using finite Abelian groups and that algebraic geometry provides a supply of such groups through Abelian varieties over finite fields. Of special interest are the Abelian varieties that are Jacobians of algebraic curves. All of the articles in this volume are centered on the theme of point counting and explicit arithmetic on the Jacobians of curves over finite fields. The topics covered include Schoof's \\ell-adic point counting algorithm, the p-adic algorithms of Kedlaya and Denef-Vercauteren, explicit arithmetic on

  5. Power Curve Measurements REWS

    DEFF Research Database (Denmark)

    Gómez Arranz, Paula; Villanueva, Héctor

    This report describes the power curve measurements carried out on a given wind turbine in a chosen period. The measurements were carried out following the measurement procedure in the draft of IEC 61400-12-1 Ed.2 [1], with some deviations mostly regarding uncertainty calculation. Here......, the reference wind speed used in the power curve is the equivalent wind speed obtained from lidar measurements at several heights between lower and upper blade tip, in combination with a hub height meteorological mast. The measurements have been performed using DTU’s measurement equipment, the analysis...

  6. Power curve investigation

    DEFF Research Database (Denmark)

    Villanueva, Héctor; Vesth, Allan

    are not performed according to IEC 61400-12-1 [1]. Therefore, the results presented in this report cannot be considered a power curve according to the reference standard, and are referred to as “power curve investigation” instead. The measurements have been performed by a customer and the data analysis has been......This report describes the analysis carried out with data from a given turbine in a wind farm and a chosen period. The purpose of the analysis is to correlate the power output of the wind turbine to the wind speed measured by a nacelle-mounted anemometer. The measurements and analysis...

  7. Paths of algebraic hyperbolic curves

    Institute of Scientific and Technical Information of China (English)

    Ya-juan LI; Li-zheng LU; Guo-zhao WANG

    2008-01-01

    Cubic algebraic hyperbolic (AH) Bezier curves and AH spline curves are defined with a positive parameter α in the space spanned by {1, t, sinht, cosht}. Modifying the value of α yields a family of AH Bezier or spline curves with the family parameter α. For a fixed point on the original curve, it will move on a defined curve called "path of AH curve" (AH Bezier and AH spline curves) when α changes. We describe the geometric effects of the paths and give a method to specify a curve passing through a given point.

  8. Incidence of surgical site infection associated with robotic surgery.

    Science.gov (United States)

    Hermsen, Elizabeth D; Hinze, Tim; Sayles, Harlan; Sholtz, Lee; Rupp, Mark E

    2010-08-01

    Robot-assisted surgery is minimally invasive and associated with less blood loss and shorter recovery time than open surgery. We aimed to determine the duration of robot-assisted surgical procedures and the incidence of postoperative surgical site infection (SSI) and to compare our data with the SSI incidence for open procedures according to national data. Retrospective cohort study. A 689-bed academic medical center. All patients who underwent a surgical procedure with use of a robotic surgical system during the period from 2000-2007. SSIs were defined and procedure types were classified according to National Healthcare Safety Network criteria. National data for comparison were from 1992-2004. Because of small sample size, procedures were grouped according to surgical site or wound classification. Sixteen SSIs developed after 273 robot-assisted procedures (5.9%). The mean surgical duration was 333.6 minutes. Patients who developed SSI had longer mean surgical duration than did patients who did not (558 vs 318 minutes; P<.001). The prostate and genitourinary group had 5.74 SSIs per 100 robot-assisted procedures (95% confidence interval [CI], 2.81-11.37), compared with 0.85 SSIs per 100 open procedures from national data. The gynecologic group had 10.00 SSIs per 100 procedures (95% CI, 2.79-30.10), compared with 1.72 SSIs per 100 open procedures. The colon and herniorrhaphy groups had 33.33 SSIs per 100 procedures (95% CI, 9.68-70.00) and 37.50 SSIs per 100 procedures (95% CI, 13.68-69.43), respectively, compared with 5.88 and 1.62 SSIs per 100 open procedures from national data. Patients with a clean-contaminated wound developed 6.1 SSIs per 100 procedures (95% CI, 3.5-10.3), compared with 2.59 SSIs per 100 open procedures. No significant differences in SSI rates were found for other groups. Increased incidence of SSI after some types of robot-assisted surgery compared with traditional open surgery may be related to the learning curve associated with use of the

  9. Nacelle lidar power curve

    DEFF Research Database (Denmark)

    Gómez Arranz, Paula; Wagner, Rozenn

    This report describes the power curve measurements performed with a nacelle LIDAR on a given wind turbine in a wind farm and during a chosen measurement period. The measurements and analysis are carried out in accordance to the guidelines in the procedure “DTU Wind Energy-E-0019” [1]. The reporting...

  10. Graphs, Curves and Dynamics

    NARCIS (Netherlands)

    Kool, J.

    2013-01-01

    This thesis has three main subjects. The first subject is Measure-theoretic rigidity of Mumford Curves. One can describe isomorphism of two compact hyperbolic Riemann surfaces of the same genus by a measure-theoretic property: a chosen isomorphism of their fundamental groups corresponds to a homeomo

  11. Power Curve Measurements

    DEFF Research Database (Denmark)

    Vesth, Allan; Kock, Carsten Weber

    The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present anal...

  12. Power Curve Measurements

    DEFF Research Database (Denmark)

    Villanueva, Héctor; Gómez Arranz, Paula

    The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...

  13. Power Curve Measurements FGW

    DEFF Research Database (Denmark)

    Gómez Arranz, Paula; Villanueva, Héctor

    The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...

  14. Fitting a Gompertz curve

    NARCIS (Netherlands)

    Ph.H.B.F. Franses (Philip Hans)

    1994-01-01

    textabstractIn this paper, a simple Gompertz curve-fitting procedure is proposed. Its advantages include the facts that the stability of the saturation level over the sample period can be checked, and that no knowledge of its value is necessary for forecasting. An application to forecasting the stoc

  15. Gompertz curves with seasonality

    NARCIS (Netherlands)

    Ph.H.B.F. Franses (Philip Hans)

    1994-01-01

    textabstractThis paper considers an extension of the usual Gompertz curve by allowing the parameters to vary over the seasons. This means that, for example, saturation levels can be different over the year. An estimation and testing method is proposed and illustrated with an example.

  16. Power Curve Measurements

    DEFF Research Database (Denmark)

    Gómez Arranz, Paula; Vesth, Allan

    The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...

  17. Power Curve Measurements, FGW

    DEFF Research Database (Denmark)

    Vesth, Allan; Yordanova, Ginka

    The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...

  18. Graphing Polar Curves

    Science.gov (United States)

    Lawes, Jonathan F.

    2013-01-01

    Graphing polar curves typically involves a combination of three traditional techniques, all of which can be time-consuming and tedious. However, an alternative method--graphing the polar function on a rectangular plane--simplifies graphing, increases student understanding of the polar coordinate system, and reinforces graphing techniques learned…

  19. Power Curve Measurements, REWS

    DEFF Research Database (Denmark)

    Villanueva, Héctor; Gómez Arranz, Paula

    This report describes the power curve measurements carried out on a given wind turbine in a chosen period. The measurements were carried out following the measurement procedure in the draft of IEC 61400-12-1 Ed.2 [1], with some deviations mostly regarding uncertainty calculation. Here, the refere...

  20. Power Curve Measurements

    DEFF Research Database (Denmark)

    Federici, Paolo; Kock, Carsten Weber

    This report describes the power curve measurements performed with a nacelle LIDAR on a given wind turbine in a wind farm and during a chosen measurement period. The measurements and analysis are carried out in accordance to the guidelines in the procedure “DTU Wind Energy-E-0019” [1]. The reporting...

  1. Carbon Lorenz Curves

    NARCIS (Netherlands)

    Groot, L.F.M.

    The purpose of this paper is twofold. First, it exhibits that standard tools in the measurement of income inequality, such as the Lorenz curve and the Gini-index, can successfully be applied to the issues of inequality measurement of carbon emissions and the equity of abatement policies across

  2. Power Curve Measurements

    DEFF Research Database (Denmark)

    Kock, Carsten Weber; Federici, Paolo

    The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine....

  3. Power Curve Measurements, FGW

    DEFF Research Database (Denmark)

    Kock, Carsten Weber; Vesth, Allan

    The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine....

  4. Alocação de modelos de produtos a equipes de trabalhadores baseada em modelos de curvas de aprendizagem Assignment of product models to worker teams using learning curve models

    Directory of Open Access Journals (Sweden)

    Michel José Anzanello

    2005-08-01

    methodology that uses learning curves to guide the best assignment of product models to teams of workers. Product models are first clustered into families based on their similarities, leading to a smaller data collection. Then allocation of product families to teams is carried based on the analysis of their corresponding learning curves. Two courses of action are then proposed, depending on whether the production batch will lead to longer or shorter production runs. The proposed methodology is illustrated in a case study from the shoe manufacturing industry.

  5. Ahead of the Digital Learning Curve

    Science.gov (United States)

    Cook, Glenn

    2013-01-01

    Dwight Carter admits he was a novice at social networking when he was introduced to the 140-character world of Twitter in 2010. Now, three years later, the principal of Ohio's Gahanna Lincoln High School and one of three winners of the 2013 National Association of Secondary School Principals (NASSP) Digital Principal Award does not know what he…

  6. Navigating the Social Media Learning Curve

    Science.gov (United States)

    Pikalek, Amy J.

    2010-01-01

    In recent years, terms such as "social media" and "social networking" have become staples in the university continuing education marketer's vocabulary. This article provides both a working knowledge of the social media landscape and practical applications of the concepts using a case study approach from a Midwestern university.…

  7. Automated Blazar Light Curves Using Machine Learning

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Spencer James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-07-27

    Every night in a remote clearing called Fenton Hill high in the Jemez Mountains of central New Mexico, a bank of robotically controlled telescopes tilt their lenses to the sky for another round of observation through digital imaging. Los Alamos National Laboratory’s Thinking Telescopes project is watching for celestial transients including high-power cosmic flashes called, and like all science, it can be messy work. To keep the project clicking along, Los Alamos scientists routinely install equipment upgrades, maintain the site, and refine the sophisticated machinelearning computer programs that process those images and extract useful data from them. Each week the system amasses 100,000 digital images of the heavens, some of which are compromised by clouds, wind gusts, focus problems, and so on. For a graduate student at the Lab taking a year’s break between master’s and Ph.D. studies, working with state-of-the-art autonomous telescopes that can make fundamental discoveries feels light years beyond the classroom.

  8. Carbon Lorenz Curves

    Energy Technology Data Exchange (ETDEWEB)

    Groot, L. [Utrecht University, Utrecht School of Economics, Janskerkhof 12, 3512 BL Utrecht (Netherlands)

    2008-11-15

    The purpose of this paper is twofold. First, it exhibits that standard tools in the measurement of income inequality, such as the Lorenz curve and the Gini-index, can successfully be applied to the issues of inequality measurement of carbon emissions and the equity of abatement policies across countries. These tools allow policy-makers and the general public to grasp at a single glance the impact of conventional distribution rules such as equal caps or grandfathering, or more sophisticated ones, on the distribution of greenhouse gas emissions. Second, using the Samuelson rule for the optimal provision of a public good, the Pareto-optimal distribution of carbon emissions is compared with the distribution that follows if countries follow Nash-Cournot abatement strategies. It is shown that the Pareto-optimal distribution under the Samuelson rule can be approximated by the equal cap division, represented by the diagonal in the Lorenz curve diagram.

  9. Managing curved canals

    Directory of Open Access Journals (Sweden)

    Iram Ansari

    2012-01-01

    Full Text Available Dilaceration is the result of a developmental anomaly in which there has been an abrupt change in the axial inclination between the crown and the root of a tooth. Dilaceration can be seen in both the permanent and deciduous dentitions, and is more commonly found in posterior teeth and in maxilla. Periapical radiographs are the most appropriate way to diagnose the presence of root dilacerations. The controlled regularly tapered preparation of the curved canals is the ultimate challenge in endodontics. Careful and meticulous technique will yield a safe and sufficient enlargement of the curved canals. This article gives a review of the literature and three interesting case reports of root dilacerations.

  10. Dynamics of curved fronts

    CERN Document Server

    Pelce, Pierre

    1989-01-01

    In recent years, much progress has been made in the understanding of interface dynamics of various systems: hydrodynamics, crystal growth, chemical reactions, and combustion. Dynamics of Curved Fronts is an important contribution to this field and will be an indispensable reference work for researchers and graduate students in physics, applied mathematics, and chemical engineering. The book consist of a 100 page introduction by the editor and 33 seminal articles from various disciplines.

  11. Estimating Corporate Yield Curves

    OpenAIRE

    Antionio Diaz; Frank Skinner

    2001-01-01

    This paper represents the first study of retail deposit spreads of UK financial institutions using stochastic interest rate modelling and the market comparable approach. By replicating quoted fixed deposit rates using the Black Derman and Toy (1990) stochastic interest rate model, we find that the spread between fixed and variable rates of interest can be modeled (and priced) using an interest rate swap analogy. We also find that we can estimate an individual bank deposit yield curve as a spr...

  12. Atypical Light Curves

    CERN Document Server

    Steenwyk, Steven D; Molnar, Lawrence A

    2013-01-01

    We have identified some two-hundred new variable stars in a systematic study of a data archive obtained with the Calvin-Rehoboth observatory. Of these, we present five close binaries showing behaviors presumably due to star spots or other magnetic activity. For context, we first present two new RS CVn systems whose behavior can be readily attribute to star spots. Then we present three new close binary systems that are rather atypical, with light curves that are changing over time in ways not easily understood in terms of star spot activity generally associated with magnetically active binary systems called RS CVn systems. Two of these three are contact binaries that exhibit gradual changes in average brightness without noticeable changes in light curve shape. A third system has shown such large changes in light curve morphology that we speculate this may be a rare instance of a system that transitions back and forth between contact and noncontact configurations, perhaps driven by magnetic cycles in at least o...

  13. Micro-surgical endodontics.

    Science.gov (United States)

    Eliyas, S; Vere, J; Ali, Z; Harris, I

    2014-02-01

    Non-surgical endodontic retreatment is the treatment of choice for endodontically treated teeth with recurrent or residual disease in the majority of cases. In some cases, surgical endodontic treatment is indicated. Successful micro-surgical endodontic treatment depends on the accuracy of diagnosis, appropriate case selection, the quality of the surgical skills, and the application of the most appropriate haemostatic agents and biomaterials. This article describes the armamentarium and technical procedures involved in performing micro-surgical endodontics to a high standard.

  14. Surgical innovation as sui generis surgical research.

    Science.gov (United States)

    Lotz, Mianna

    2013-12-01

    Successful innovative 'leaps' in surgical technique have the potential to contribute exponentially to surgical advancement, and thereby to improved health outcomes for patients. Such innovative leaps often occur relatively spontaneously, without substantial forethought, planning, or preparation. This feature of surgical innovation raises special challenges for ensuring sufficient evaluation and regulatory oversight of new interventions that have not been the subject of controlled investigatory exploration and review. It is this feature in particular that makes early-stage surgical innovation especially resistant to classification as 'research', with all of the attendant methodological and ethical obligations--of planning, regulation, monitoring, reporting, and publication--associated with such a classification. This paper proposes conceptual and ethical grounds for a restricted definition according to which innovation in surgical technique is classified as a form of sui generis surgical 'research', where the explicit goal of adopting such a definition is to bring about needed improvements in knowledge transfer and thereby benefit current and future patients.

  15. Study on the Cost of Solar Photovoltaic Power Generation Using Double-factors Learning Curve Model%太阳能光伏发电成本的双因素学习曲线模型研究

    Institute of Scientific and Technical Information of China (English)

    曾鸣; 鹿伟; 段金辉; 李娜

    2012-01-01

    随着太阳能这一新能源的开发,在低碳经济时代,降低光伏发电成本以提高其可利用性显得尤为重要.在Wright基本学习曲线模型的基础上,建立太阳能光伏发电的双因素学习曲线模型,研究了太阳能光伏组件累积生产量和累积研发量对太阳能光伏发电成本的影响.采用2001年至2010年10a的数据,运用最小二乘法,检验参数的显著性,进而确定模型的可行性.并利用此双因素学习曲线模型对我国未来10a的太阳能光伏发电成本做了预测,得出在累积生产量和累积研发量发展情况不同的情形下,光伏发电成本的降低程度不同.表明应大力开发太阳能光伏发电产业,平衡累积生产量和累积研发量,使太阳能光伏发电的成本降低.同时对如何降低光伏发电成本提出了建议,为政策制定者提供一定的参考.%Along with the development of solar energy, it is particularly important to reduce the cost of solar photovoltaic power generation to improve its availability for low carbon economic. The double- factors learning curve model of solar photovoltaic power generation is built based on the Wright's basic learning curve model, and the influence of the accumulated production amount and the accumulated research and development amount of solar photovoltaic modules on the cost of solar photovoltaic power generation is studied. The ten- year data between 2001 and 2010 are used to test the significance of the parameters and to confirm the feasibility of the model by using of the least square method. In the end, the cost of solar photovoltaic power generation in future ten years is predicted, and the conclusion is that the cost of solar photovoltaic power generation reduces in different degree under different development situation. At the same time, proposals for reducing the cost are given, which provides certain reference for policy makers.

  16. Optimising surgical training: use of feedback to reduce errors during a simulated surgical procedure.

    LENUS (Irish Health Repository)

    Boyle, Emily

    2011-08-01

    To assess the effect of proximate or immediate feedback during an intensive training session. The authors hypothesised that provision of feedback during a training session would improve performance and learning curves.

  17. Caloric curve of star clusters.

    Science.gov (United States)

    Casetti, Lapo; Nardini, Cesare

    2012-06-01

    Self-gravitating systems, such as globular clusters or elliptical galaxies, are the prototypes of many-body systems with long-range interactions, and should be the natural arena in which to test theoretical predictions on the statistical behavior of long-range-interacting systems. Systems of classical self-gravitating particles can be studied with the standard tools of equilibrium statistical mechanics, provided the potential is regularized at small length scales and the system is confined in a box. The confinement condition looks rather unphysical in general, so that it is natural to ask whether what we learn with these studies is relevant to real self-gravitating systems. In order to provide an answer to this question, we consider a basic, simple, yet effective model of globular clusters: the King model. This model describes a self-consistently confined system, without the need of any external box, but the stationary state is a nonthermal one. In particular, we consider the King model with a short-distance cutoff on the interactions, and we discuss how such a cutoff affects the caloric curve, i.e., the relation between temperature and energy. We find that the cutoff stabilizes a low-energy phase, which is absent in the King model without cutoff; the caloric curve of the model with cutoff turns out to be very similar to that of previously studied confined and regularized models, but for the absence of a high-energy gaslike phase. We briefly discuss the possible phenomenological as well as theoretical implications of these results.

  18. [Coblation tonsillectomy under surgical microscopy].

    Science.gov (United States)

    Fujihara, Keiji; Kohno, Masamitu; Ogami, Masashi; Hayashi, Masaki; Togawa, Akihisa; Tamura, Shinji; Yamanaka, Noboru

    2011-12-01

    Numbers of tonsillectomies may be decreasing in Japan due to troublesome bleeding involved in managing in a small viewing field and relatively low national health insurance point for tonsillectomy. We found coblation tonsillectomy to have advantages of less bleeding, shorter operating time, and less postoprerative pain than conventional tonsillectomy. We found that 40% of those on whom a coblator was used reported no postoperative throat pain, and noted a quick learning curve in decreasing postoperative bleeding in coblation tonsillectomy.

  19. Curved PVDF airborne transducer.

    Science.gov (United States)

    Wang, H; Toda, M

    1999-01-01

    In the application of airborne ultrasonic ranging measurement, a partially cylindrical (curved) PVDF transducer can effectively couple ultrasound into the air and generate strong sound pressure. Because of its geometrical features, the ultrasound beam angles of a curved PVDF transducer can be unsymmetrical (i.e., broad horizontally and narrow vertically). This feature is desired in some applications. In this work, a curved PVDF air transducer is investigated both theoretically and experimentally. Two resonances were observed in this transducer. They are length extensional mode and flexural bending mode. Surface vibration profiles of these two modes were measured by a laser vibrometer. It was found from the experiment that the surface vibration was not uniform along the curvature direction for both vibration modes. Theoretical calculations based on a model developed in this work confirmed the experimental results. Two displacement peaks were found in the piezoelectric active direction of PVDF film for the length extensional mode; three peaks were found for the flexural bending mode. The observed peak positions were in good agreement with the calculation results. Transient surface displacement measurements revealed that vibration peaks were in phase for the length extensional mode and out of phase for the flexural bending mode. Therefore, the length extensional mode can generate a stronger ultrasound wave than the flexural bending mode. The resonance frequencies and vibration amplitudes of the two modes strongly depend on the structure parameters as well as the material properties. For the transducer design, the theoretical model developed in this work can be used to optimize the ultrasound performance.

  20. Magnetism in curved geometries

    Science.gov (United States)

    Streubel, Robert; Fischer, Peter; Kronast, Florian; Kravchuk, Volodymyr P.; Sheka, Denis D.; Gaididei, Yuri; Schmidt, Oliver G.; Makarov, Denys

    2016-09-01

    Extending planar two-dimensional structures into the three-dimensional space has become a general trend in multiple disciplines, including electronics, photonics, plasmonics and magnetics. This approach provides means to modify conventional or to launch novel functionalities by tailoring the geometry of an object, e.g. its local curvature. In a generic electronic system, curvature results in the appearance of scalar and vector geometric potentials inducing anisotropic and chiral effects. In the specific case of magnetism, even in the simplest case of a curved anisotropic Heisenberg magnet, the curvilinear geometry manifests two exchange-driven interactions, namely effective anisotropy and antisymmetric exchange, i.e. Dzyaloshinskii-Moriya-like interaction. As a consequence, a family of novel curvature-driven effects emerges, which includes magnetochiral effects and topologically induced magnetization patterning, resulting in theoretically predicted unlimited domain wall velocities, chirality symmetry breaking and Cherenkov-like effects for magnons. The broad range of altered physical properties makes these curved architectures appealing in view of fundamental research on e.g. skyrmionic systems, magnonic crystals or exotic spin configurations. In addition to these rich physics, the application potential of three-dimensionally shaped objects is currently being explored as magnetic field sensorics for magnetofluidic applications, spin-wave filters, advanced magneto-encephalography devices for diagnosis of epilepsy or for energy-efficient racetrack memory devices. These recent developments ranging from theoretical predictions over fabrication of three-dimensionally curved magnetic thin films, hollow cylinders or wires, to their characterization using integral means as well as the development of advanced tomography approaches are in the focus of this review.

  1. Modeling of a flexible instrument to study its sliding behavior inside a curved endoscope

    NARCIS (Netherlands)

    Khatait, Jitendra; Brouwer, Dannis Michel; Aarts, Ronald G.K.M.; Herder, Justus Laurens

    2013-01-01

    Flexible instruments are increasingly used to carry out surgical procedures. The instrument tip is remotely controlled by the surgeon. The flexibility of the instrument and the friction inside the curved endoscope jeopardize the control of the instrument tip. Characterization of the surgical

  2. Superfluids in Curved Spacetime

    CERN Document Server

    Villegas, Kristian Hauser A

    2015-01-01

    Superfluids under an intense gravitational field are typically found in neutron star and quark star cores. Most treatments of these superfluids, however, are done in a flat spacetime background. In this paper, the effect of spacetime curvature on superfluidity is investigated. An effective four-fermion interaction is derived by integrating out the mediating scalar field. The fermions interacting via the mediating gauge vector bosons is also discussed. Two possible cases are considered in the mean-field treatment: antifermion-fermion and fermion-fermion pairings. An effective action, quadratic in fermion field, and a self-consistent equation are derived for both cases. The effective Euclidean action and the matrix elements of the heat kernel operator, which are very useful in curved-spacetime QFT calculations, are derived for the fermion-fermion pairing. Finally, explicit numerical calculation of the gravitational correction to the pairing order parameter is performed for the scalar superfluid case. It is foun...

  3. Polymers in Curved Boxes

    CERN Document Server

    Yaman, K; Solis, F J; Witten, T A

    1996-01-01

    We apply results derived in other contexts for the spectrum of the Laplace operator in curved geometries to the study of an ideal polymer chain confined to a spherical annulus in arbitrary space dimension D and conclude that the free energy compared to its value for an uncurved box of the same thickness and volume, is lower when $D < 3$, stays the same when $D = 3$, and is higher when lowers the effective bending elasticity of the walls, and might induce spontaneous symmetry breaking, i.e. bending. (Actually, the above mentioned results show that {\\em {any}} shell in $D = 3$ induces this effect, except for a spherical shell). We compute the contribution of this effect to the bending rigidities in the Helfrich free energy expression.

  4. Evolutes of Hyperbolic Plane Curves

    Institute of Scientific and Technical Information of China (English)

    Shyuichi IZUMIYA; Dong He PEI; Takashi SANO; Erika TORII

    2004-01-01

    We define the notion of evolutes of curves in a hyperbolic plane and establish the relationships between singularities of these subjects and geometric invariants of curves under the action of the Lorentz group. We also describe how we can draw the picture of an evolute of a hyperbolic plane curve in the Poincar(e) disk.

  5. The Arithmetic of Elliptic Curves

    CERN Document Server

    Silverman, Joseph H

    2009-01-01

    Treats the arithmetic theory of elliptic curves in its modern formulation, through the use of basic algebraic number theory and algebraic geometry. This book discusses the necessary algebro-geometric results, and offers an exposition of the geometry of elliptic curves, and the formal group of an elliptic curve.

  6. Curved-Duct

    Directory of Open Access Journals (Sweden)

    Je Hyun Baekt

    2000-01-01

    Full Text Available A numerical study is conducted on the fully-developed laminar flow of an incompressible viscous fluid in a square duct rotating about a perpendicular axis to the axial direction of the duct. At the straight duct, the rotation produces vortices due to the Coriolis force. Generally two vortex cells are formed and the axial velocity distribution is distorted by the effect of this Coriolis force. When a convective force is weak, two counter-rotating vortices are shown with a quasi-parabolic axial velocity profile for weak rotation rates. As the rotation rate increases, the axial velocity on the vertical centreline of the duct begins to flatten and the location of vorticity center is moved near to wall by the effect of the Coriolis force. When the convective inertia force is strong, a double-vortex secondary flow appears in the transverse planes of the duct for weak rotation rates but as the speed of rotation increases the secondary flow is shown to split into an asymmetric configuration of four counter-rotating vortices. If the rotation rates are increased further, the secondary flow restabilizes to a slightly asymmetric double-vortex configuration. Also, a numerical study is conducted on the laminar flow of an incompressible viscous fluid in a 90°-bend square duct that rotates about axis parallel to the axial direction of the inlet. At a 90°-bend square duct, the feature of flow by the effect of a Coriolis force and a centrifugal force, namely a secondary flow by the centrifugal force in the curved region and the Coriolis force in the downstream region, is shown since the centrifugal force in curved region and the Coriolis force in downstream region are dominant respectively.

  7. Hernia Surgical Mesh Implants

    Science.gov (United States)

    ... Prosthetics Hernia Surgical Mesh Implants Hernia Surgical Mesh Implants Share Tweet Linkedin Pin it More sharing options ... majority of tissue used to produce these mesh implants are from a pig (porcine) or cow (bovine) ...

  8. Urogynecologic Surgical Mesh Implants

    Science.gov (United States)

    ... Prosthetics Urogynecologic Surgical Mesh Implants Urogynecologic Surgical Mesh Implants Share Tweet Linkedin Pin it More sharing options ... majority of tissue used to produce these mesh implants are from a pig (porcine) or cow (bovine). ...

  9. American Pediatric Surgical Association

    Science.gov (United States)

    American Pediatric Surgical Association Search for: Login Resources + For Members For Professionals For Training Program Directors For Media For ... Surgical Outcomes Surveys & Results Publications Continuing Education + ExPERT Pediatric Surgery NaT Annual Meeting CME MOC Requirements Residents / ...

  10. Optimizing surgical f

    Directory of Open Access Journals (Sweden)

    Sabry Mohamed Amin

    2016-07-01

    Conclusions: In our study both dexmedetomidine and esmolol were effective in reducing MABP, and lowering the heart rate providing dry surgical field and ensured good surgical condition during cochlear implant surgery in pediatric patients.

  11. Abortion - surgical - aftercare

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000658.htm Abortion - surgical - aftercare To use the sharing features on ... please enable JavaScript. You have had a surgical abortion. This is a procedure that ends pregnancy by ...

  12. Surgical training in the Netherlands.

    Science.gov (United States)

    Borel-Rinkes, Inne H M; Gouma, Dirk J; Hamming, Jaap F

    2008-10-01

    Surgical training in the Netherlands has traditionally been characterized by learning on the job under the classic master-trainee doctrine. Over the past decades, it has become regionally organized with intensive structural training courses, and a peer-based quality control system. Recently, the nationwide programme has been modernized further and now involves a systematic, competency-based education with structural training courses, formalized assessment and room for reflection by residents under the supervision of surgical teaching groups. To this end, a uniform web-based digital portfolio is being introduced to facilitate monitoring of the individual resident's progress. Though requiring inspirational leadership, commitment, and determination, this modernization has sparked enthusiasm among trainees and teachers.

  13. Soil Water Retention Curve

    Science.gov (United States)

    Johnson, L. E.; Kim, J.; Cifelli, R.; Chandra, C. V.

    2016-12-01

    Potential water retention, S, is one of parameters commonly used in hydrologic modeling for soil moisture accounting. Physically, S indicates total amount of water which can be stored in soil and is expressed in units of depth. S can be represented as a change of soil moisture content and in this context is commonly used to estimate direct runoff, especially in the Soil Conservation Service (SCS) curve number (CN) method. Generally, the lumped and the distributed hydrologic models can easily use the SCS-CN method to estimate direct runoff. Changes in potential water retention have been used in previous SCS-CN studies; however, these studies have focused on long-term hydrologic simulations where S is allowed to vary at the daily time scale. While useful for hydrologic events that span multiple days, the resolution is too coarse for short-term applications such as flash flood events where S may not recover its full potential. In this study, a new method for estimating a time-variable potential water retention at hourly time-scales is presented. The methodology is applied for the Napa River basin, California. The streamflow gage at St Helena, located in the upper reaches of the basin, is used as the control gage site to evaluate the model performance as it is has minimal influences by reservoirs and diversions. Rainfall events from 2011 to 2012 are used for estimating the event-based SCS CN to transfer to S. As a result, we have derived the potential water retention curve and it is classified into three sections depending on the relative change in S. The first is a negative slope section arising from the difference in the rate of moving water through the soil column, the second is a zero change section representing the initial recovery the potential water retention, and the third is a positive change section representing the full recovery of the potential water retention. Also, we found that the soil water moving has traffic jam within 24 hours after finished first

  14. Surgical infection in art.

    Science.gov (United States)

    Meakins, J L

    1996-12-01

    The earliest images of medicine and surgery in Western art are from the late Middle Ages. Although often attractive, at that time they were illustrative and mirrored the text on how to diagnose or treat a specific condition. These drawings in medieval manuscripts represent management of abscesses, perianal infection and fistulas, amputation, and wound dressings. With the Renaissance, art in all its forms flourished, and surgeons were represented at work draining carbuncles, infected bursae, and mastoiditis; managing ulcers, scrofula, and skin infections; and performing amputations. Specific diagnosis can be made, such as streptococcal infection in the discarded leg of the miraculous transplantation performed by Saints Cosmas and Damian and in the works of Rembrandt van Rijn and Frederic Bazille. Evocations of cytokine activity are evident in works by Albrecht Dürer, Edvard Munch, and James Tissot. The iconography of society's view of a surgeon is apparent and often not complimentary. The surgeon's art is a visual art. Astute observation leads to early diagnosis and better results in surgical infection and the septic state. Learning to see what we look at enhances our appreciation of the world around us but, quite specifically, makes us better clinicians.

  15. Cubic B-spline curve approximation by curve unclamping

    OpenAIRE

    Chen, Xiao-Diao; Ma, Weiyin; Paul, Jean-Claude

    2010-01-01

    International audience; A new approach for cubic B-spline curve approximation is presented. The method produces an approximation cubic B-spline curve tangent to a given curve at a set of selected positions, called tangent points, in a piecewise manner starting from a seed segment. A heuristic method is provided to select the tangent points. The first segment of the approximation cubic B-spline curve can be obtained using an inner point interpolation method, least-squares method or geometric H...

  16. Surgical Lasers In Gynecology

    Science.gov (United States)

    Schellhas, Helmut F.; Barnes, Alfonso E.

    1982-12-01

    Multipurpose surgical CO2 lasers marketed in the USA have been developed to be applicable to a variety of surgical procedures in many surgical fields. They are all suited for endoscopic surgical procedures and can be fitted to all standard surgical microscopes. They all can adjust the focal length of the laser beam to the different standard focal lengths of the surgical microscope which for instance in laryngoscopy is 400 mm and in colposcopy 300 mm. One laser instrument can even change the spot size in a given focal distance which is very advantageous for some microsurgical procedures (Merrimack Laboratories 820). All multipurpose surgical CO2 laser systems provide a multi-articulated surgical arm for free-hand surgery. The surgical arms are cumbersome to use but they are adapted to the surgeons needs with ingenuity. The practicality of the multi-articulated surgical arms depends mostly on the distance of the handpiece from the surgical console which now is also overbridged by the laser tube in most surgical laser system. The spot size of the beam is variable in most handpieces by interchangeable lenses which modify the focal distance of the beam and the power density. Another common feature in all systems is a coaxial He-Ne pilot light which provides a red spot which unfortunately becomes invisible in a bleeding surgical field. Most surgical laser systems have a spacial mode of TEM 00 which is essential for incisional surgery. The continuous mode of beam delivery is used for incisional surgery and also for most endoscopic procedures.

  17. Kolb经验学习理论在“外科护理学”教学活动中应用的效果评价%Application of Kolb experience learning theory in Surgical Nursing teaching

    Institute of Scientific and Technical Information of China (English)

    刘燕南; 彭艾莉; 姚珺; 岳琳; 谌绍林

    2014-01-01

    目的 探讨Kolb经验学习理论在“外科护理学”教学中的应用效果.方法 便利抽取2012级护理专业2个大班120人为研究对象,随机分为2组,对照组实施传统教学,观察组实施基于Kolb经验学习理论的教学模式,实验结束后,采用理论考试、实践考核、问卷调查对教学实效性进行评价.结果 2组学生的理论考试成绩、实践考核成绩和学习效果各维度比较差异有统计学意义.结论 基于Kolb经验学习理论的“外科护理学”教学模式的开展能提高学生的学习兴趣和学习效果,利于教学改革的实施.%Objective To investigate the effect of the Kolb experience learning theory applied in Surgical Nursing teaching.Methods 120 students were selected randomly and were divided into 2 groups,the observation group operated the teaching mode based on the Kolb experience learning theory,the control group operated traditional teaching.After the experiment,using the theory test,the skill test,the questionnaire survey to evaluate the teaching effectiveness.Results The two groups showed statistical difference in theory exam results,learning effect of each dimension and evaluation of teaching effect.Conclusions The teaching mode based on the Kolb experience learning theory can improve the students' interest in learning and study effect,and push forward the reform of teaching implementatiou.

  18. ANALYSIS OF THE SECONDARY CURVES IN PATIENTS UNDERGOING SELECTIVE ARTHRODESIS LENKE I

    Directory of Open Access Journals (Sweden)

    TADEU GERVAZONI DEBOM

    2015-12-01

    Full Text Available Objective : To radiographically evaluate the behavior of the secondary curves in the coronal and sagittal planes in patients with AIS classified as Lenke I, who underwent surgical treatment of selective arthrodesis by posterior approach. Methods : Retrospective study which analyzed 40 patients with AIS, being 33 female. The measurement of the radiographic parameters used followed the recommendations by Cobb. Results : The average correction of the thoracic proximal, primary and lumbar curves was 34.73%, 75.06% and 64.64%, respectively. Conclusion : Surgical treatment by selective arthrodesis in cases of AIS Lenke type I provide correction of compensatory curves in the coronal and maintenance in the sagittal plane.

  19. Lesson plans in surgical training.

    Science.gov (United States)

    Lester, S E; Robson, A K R

    2007-06-01

    Lesson plans in surgery enable trainers and trainees to agree on goals that balance training needs with service commitments. Lesson plans are individualised to the trainee and encourage ownership of learning. They are based on SMART criteria and therefore have a sound educational footing. Most of the work in creating a lesson plan falls to the trainee. The total time for creation of each plan is approximately 20 min. Our use of lesson plans for surgical training has been met with favourable response from both trainer and trainees.

  20. Surgical Treatment of Adult Degenerative Scoliosis

    OpenAIRE

    Cho, Kyu-Jung; Kim, Young-tae; Shin, Sang-hyun; Suk, Se-Il

    2014-01-01

    The rapid increase of elderly population has resulted in increased prevalence of adult scoliosis. Adult scoliosis is divided into adult idiopathic scoliosis and adult degenerative scoliosis. These two types of scoliosis vary in patient age, curve pattern and clinical symptoms, which necessitate different surgical indications and options. Back pain and deformity are major indications for surgery in adult idiopathic scoliosis, whereas radiating pain to the legs due to foraminal stenosis is what...

  1. Social Media: Changing the Paradigm for Surgical Education.

    Science.gov (United States)

    Petrucci, Andrea M; Chand, Manish; Wexner, Steven D

    2017-09-01

    The role of social media (SoMe) in surgical education is emerging as a tool that augments and complements traditional learning. As SoMe usage has steadily increased in our personal and professional lives, it is no surprise that it has permeated into surgical education. Different SoMe sites offer distinct platforms from which knowledge can be transmitted, while catering to various learning styles. The purpose of this review is to outline the various SoMe platforms and their use in surgical education. Moreover, it will discuss their effectiveness in teaching and learning surgical knowledge and skills as well as other potential roles SoMe has to offer to improve surgical education.

  2. Proposal of a synthetic ethylene-vinyl acetate bench model for surgical foundations learning: suture training Modelo de bancada sintético de etileno vinil acetato para a aprendizagem das bases da cirurgia: treinamento de suturas

    Directory of Open Access Journals (Sweden)

    Érika Malheiros Bastos

    2011-04-01

    Full Text Available Due to ethical and legal aspects involved in the handling of cadavers and animals the synthetic simulators are an alternative for learning how to suture technique plus the practice of various procedures such as incision and surgical flap. In this context, this paper describes and propose the use of a synthetic model manufactured from plates of ethylene-vinyl acetate (EVA to teach primary surgical skills in medical students with no previous exposure to surgery. The model that provides the convenience of being easily reproducible, allowing the students in training can thus improve their skills before applying the technique in clinical practice.Devido aos aspectos éticos e legais envolvidos no manuseio de cadáveres e animais, os simuladores sintéticos surgem como alternativa para o ensino-aprendizagem de técnicas de sutura e simulação de procedimentos, como a confecção de incisões e retalhos cirúrgicos. Neste âmbito é proposto e descrito um modelo de bancada sintético confeccionado a partir de etileno vinil acetato (EVA para o ensino de habilidades cirúrgicas básicas, em estudantes de medicina sem exposição prévia a cirurgia. O modelo fornece a praticidade de ser reprodutível, barato e de fácil aquisição, possibilitando que o acadêmico em formação possa, portanto, aperfeiçoar suas habilidades antes de aplicar a técnica na prática clínica.

  3. A prospective randomized comparison of curved array and radial echoendoscopy in patients with esophageal cancer

    DEFF Research Database (Denmark)

    Siemsen, Mette; Svendsen, Lars Bo; Knigge, Ulrich

    2003-01-01

    BACKGROUND: Both curved array and radial scanning echoendoscopy are used for locoregional staging of cancer arising in the esophagus or cardia. The accuracy of TNM staging of these malignancies by curved array and radial EUS was compared in a prospective, randomized study. METHODS: Patients...... with surgical and histopathologic staging. RESULTS: A total of 104 patients underwent EUS; 36 had surgical resection of the tumor, 26 surgical exploration without resection, and 42 did not undergo surgery. Comparison of the TNM staging results for the two echoendoscopies gave high kappa values (T, 0.77; N, 0.......75; M, 0.89), indicating excellent agreement. The accuracy of curved array echoendoscopy and radial echoendoscopy by component of the TNM staging system were, respectively, T, 72% and 73%; N, 70% and 77%; and M, 61% and 57%. Mean procedure time for the curved array and radial examinations was...

  4. Liability exposure for surgical robotics instructors.

    Science.gov (United States)

    Lee, Yu L; Kilic, Gokhan; Phelps, John Y

    2012-01-01

    Surgical robotics instructors provide an essential service in improving the competency of novice gynecologic surgeons learning robotic surgery and advancing surgical skills on behalf of patients. However, despite best intentions, robotics instructors and the gynecologists who use their services expose themselves to liability. The fear of litigation in the event of a surgical complication may reduce the availability and utility of robotics instructors. A better understanding of the principles of duty of care and the physician-patient relationship, and their potential applicability in a court of law likely will help to dismantle some concerns and uncertainties about liability. This commentary is not meant to discourage current and future surgical instructors but to raise awareness of liability issues among robotics instructors and their students and to recommend certain preventive measures to curb potential liability risks.

  5. Reflection of curved shock waves

    Science.gov (United States)

    Mölder, S.

    2017-03-01

    Shock curvatures are related to pressure gradients, streamline curvatures and vorticity in flows with planar and axial symmetry. Explicit expressions, in an influence coefficient format, are used to relate post-shock pressure gradient, streamline curvature and vorticity to pre-shock gradients and shock curvature in steady flow. Using higher order, von Neumann-type, compatibility conditions, curved shock theory is applied to calculate the flow near singly and doubly curved shocks on curved surfaces, in regular shock reflection and in Mach reflection. Theoretical curved shock shapes are in good agreement with computational fluid dynamics calculations and experiment.

  6. Reflection of curved shock waves

    Science.gov (United States)

    Mölder, S.

    2017-09-01

    Shock curvatures are related to pressure gradients, streamline curvatures and vorticity in flows with planar and axial symmetry. Explicit expressions, in an influence coefficient format, are used to relate post-shock pressure gradient, streamline curvature and vorticity to pre-shock gradients and shock curvature in steady flow. Using higher order, von Neumann-type, compatibility conditions, curved shock theory is applied to calculate the flow near singly and doubly curved shocks on curved surfaces, in regular shock reflection and in Mach reflection. Theoretical curved shock shapes are in good agreement with computational fluid dynamics calculations and experiment.

  7. Heegner modules and elliptic curves

    CERN Document Server

    Brown, Martin L

    2004-01-01

    Heegner points on both modular curves and elliptic curves over global fields of any characteristic form the topic of this research monograph. The Heegner module of an elliptic curve is an original concept introduced in this text. The computation of the cohomology of the Heegner module is the main technical result and is applied to prove the Tate conjecture for a class of elliptic surfaces over finite fields; this conjecture is equivalent to the Birch and Swinnerton-Dyer conjecture for the corresponding elliptic curves over global fields.

  8. Closed planar curves without inflections

    CERN Document Server

    Ohno, Shuntaro; Umehara, Masaaki

    2011-01-01

    We define a computable topological invariant $\\mu(\\gamma)$ for generic closed planar regular curves $\\gamma$, which gives an effective lower bound for the number of inflection points on a given generic closed planar curve. Using it, we classify the topological types of locally convex curves (i.e. closed planar regular curves without inflections) whose numbers of crossings are less than or equal to five. Moreover, we discuss the relationship between the number of double tangents and the invariant $\\mu(\\gamma)$ on a given $\\gamma$.

  9. Enhancing surgical innovation through a specialized medical school pathway of excellence in innovation and entrepreneurship: Lessons learned and opportunities for the future.

    Science.gov (United States)

    Cohen, Mark S

    2017-08-01

    The mission of an academic medical center and academic departments of surgery focuses on teaching, scholarship/research, and expertise of clinical care. The standard 4-year medical school curriculum and general surgery residency training are well balanced to expose trainees to these missions in varying degrees, yet the advancement of medicine as a field is predicated on the creation, development, and successful implementation of medical innovations. Surgeons, by virtue of their clinical training, are immersed in medical technology and are continually required to use this technology effectively in combination with their own technical skills and judgment to provide optimal patient care. As such, they routinely face the challenges of current technology and the need for innovation and improvement, leading many to become natural inventors. Having a good idea or innovation to improve patient care, however, is just the starting point of the complex process of implementing that idea in the clinic. Unfortunately, the vast majority of surgeons and medical students have no formal educational training on the innovation process regarding how good ideas can be developed successfully for clinical and commercial implementation. Added to this lack of formal education are the limited resources and time constraints that surgeons, residents, and medical students face in acquiring the educational skill set to adeptly navigate this innovation and entrepreneurial landscape. To address these challenges, the University of Michigan recently created the first pathway of excellence for medical students to focus their passions and interests in medical innovation and entrepreneurship. This program has been transformative for building a new culture of young, motivated medical innovators, many of whom have dedicated their talents already to addressing several key problems in surgical patient care. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Simulation-based surgical education.

    Science.gov (United States)

    Evgeniou, Evgenios; Loizou, Peter

    2013-09-01

    The reduction in time for training at the workplace has created a challenge for the traditional apprenticeship model of training. Simulation offers the opportunity for repeated practice in a safe and controlled environment, focusing on trainees and tailored to their needs. Recent technological advances have led to the development of various simulators, which have already been introduced in surgical training. The complexity and fidelity of the available simulators vary, therefore depending on our recourses we should select the appropriate simulator for the task or skill we want to teach. Educational theory informs us about the importance of context in professional learning. Simulation should therefore recreate the clinical environment and its complexity. Contemporary approaches to simulation have introduced novel ideas for teaching teamwork, communication skills and professionalism. In order for simulation-based training to be successful, simulators have to be validated appropriately and integrated in a training curriculum. Within a surgical curriculum, trainees should have protected time for simulation-based training, under appropriate supervision. Simulation-based surgical education should allow the appropriate practice of technical skills without ignoring the clinical context and must strike an adequate balance between the simulation environment and simulators.

  11. Manual of Surgical Instruments

    Directory of Open Access Journals (Sweden)

    Olga Lidia Sánchez Sarría

    2014-10-01

    Full Text Available Surgical instruments are the group of tools used in surgical procedures. They are very expensive and sophisticated. Consequently, a standardized and meticulous care is essential; they should go through the decontamination, cleaning and sterilization process. These instruments are designed in order to provide surgeons with tools that help them to perform a basic surgical procedure; there are multiple variations and the design depends on their function. This paper aims at showing all surgical instruments that can be used in an operating room during surgery and are not generally included in the medical literature.

  12. Migration and the Wage Curve:

    DEFF Research Database (Denmark)

    Brücker, Herbert; Jahn, Elke J.

      Based on a wage curve approach we examine the labor market effects of migration in Germany. The wage curve relies on the assumption that wages respond to a change in the unemployment rate, albeit imperfectly. This allows one to derive the wage and employment effects of migration simultaneously...

  13. NURBS curve blending using extension

    Institute of Scientific and Technical Information of China (English)

    Yong-jin LIU; Rong-qi QIU; Xiao-hui LIANG

    2009-01-01

    Curve and surface blending is an important operation in CAD systems, in which a non-uniform rational B-spline (NURBS) has been used as the de facto standard. In local comer blending, two curves intersecting at that comer are first made disjoint, and then the third blending curve is added-in to smoothly join the two curves with G1-or G2-continuity. In this paper we present a study to solve the joint problem based on curve extension. The following nice properties of this extension algorithm are exploited in depth: (1) The parameterization of the original shapes does not change; (2) No additional fragments are created.Various examples are presented to demonstrate that our solution is simple and efficient.

  14. Surgical ethics and the challenge of surgical innovation.

    Science.gov (United States)

    Angelos, Peter

    2014-12-01

    Surgical ethics as a specific discipline is relatively new to many. Surgical ethics focuses on the ethical issues that are particularly important to the care of surgical patients. Informed consent for surgical procedures, the level of responsibility that surgeons feel for their patients' outcomes, and the management of surgical innovation are specific issues that are important in surgical ethics and are different from other areas of medicine. The future of surgical progress is dependent on surgical innovation, yet the nature of surgical innovation raises specific concerns that challenge the professionalism of surgeons. These concerns will be considered in the following pages.

  15. Fuzzy-logic-assisted surgical planning in adolescent idiopathic scoliosis.

    Science.gov (United States)

    Nault, Marie-Lyne; Labelle, Hubert; Aubin, Carl-Eric; Sangole, Archana; Balazinski, Marek

    2009-06-01

    Selection of appropriate curve fusion levels for surgery in adolescent idiopathic scoliosis (AIS) is a complex and difficult task and, despite numerous publications, still remains a highly controversial topic. To evaluate a fuzzy-logic-based surgical planning tool by comparing the results suggested by the software with the average outcome recommended by a panel of 5 expert spinal deformity surgeons. It is hypothesized that, given the same information, the fuzzy-logic tool will perform as favorably as the surgeons. Proof-of-concept study evaluating the use of a fuzzy-logic-assisted surgical planning tool in AIS to select the appropriate spinal curve to be instrumented. A cohort of 30 AIS surgical cases with a main thoracic curve was used. Each case included standard measurements recorded from preoperative standing postero-anterior and lateral, supine side bending, and 1-year postoperative standing radiographs. Five experienced spinal deformity surgeons evaluated each case independently and gave their preferred levels of instrumentation and fusion. The cases were then presented to the fuzzy-logic tool to determine whether the high thoracic and/or lumbar curves were to be instrumented. For each case, a percentage value was obtained indicating inclusion/exclusion of the respective curves in the surgical instrumentation procedure. Kappa statistics was used to compare the model output and the average decision of the surgeons. Kappa values of 0.71 and 0.64 were obtained, respectively, for the proximal thoracic and lumbar curves models, thus suggesting a good agreement of the fusion recommendations made by the fuzzy-logic tool and the surgeons. Given the same information, the fuzzy-logic-assisted recommendation of the curve to be instrumented compared favorably with the collective decision of the surgeons. The findings thus suggest that a fuzzy-logic approach is helpful in assisting surgeons with the preoperative selection of curve instrumentation and fusion levels in AIS.

  16. Recognizing surgical patterns

    NARCIS (Netherlands)

    Bouarfa, L.

    2012-01-01

    In the Netherlands, each year over 1700 patients die from preventable surgical errors. Numerous initiatives to improve surgical practice have had some impact, but problems persist. Despite the introduction of checklists and protocols, patient safety in surgery remains a continuing challenge. This is

  17. Surgical medical record

    DEFF Research Database (Denmark)

    Bulow, S.

    2008-01-01

    A medical record is presented on the basis of selected linguistic pearls collected over the years from surgical case records Udgivelsesdato: 2008/12/15......A medical record is presented on the basis of selected linguistic pearls collected over the years from surgical case records Udgivelsesdato: 2008/12/15...

  18. Does robot-assisted laparoscopic radical prostatectomy enable to obtain adequate oncological and functional outcomes during the learning curve? From the Korean experience%在学习曲线中观察机器人辅助腹腔镜前列腺根除术能否得到充分的肿瘤学和功能性结果?来自韩国的经验

    Institute of Scientific and Technical Information of China (English)

    Young Hwii Ko; Jeong Hyeon Ban; Seok Ho Kang; Hong Seok Park; Jeong Gu Lee; Duck Ki Yoon; Je Jong Kim; Jun Cheon; Vipul R. Patei

    2009-01-01

    To estimate the short-term results of robot-assisted laparoscopic radical prostatectomy (RALRP) during the learning curve, in terms of surgical, oncologicai and functional outcomes, we conducted a prospective survey on RALRP. From July 2007, a single surgeon performed 63 robotic prostatectomies using the same operative technique. Perioperative data, including pathological and early functional results of the patient, were collected prospectively and analyzed. Along with the accumulation of the cases, the total operative time, setup time, console time and blood loss were significantly decreased. No major complication was present in any patient. Transfusion was needed in six patients; all of them were within the initial 15 cases. The positive surgical margin rate was 9.8% (5/51) in pT2 disease. The most frequent location of positive margin in this stage was the lateral aspect (60%), but in pT3 disease multiple margins were the most frequent (41.7%). Overall, 53 (84.1%) patients had totally continent status and the median time to continence was 6.56 weeks. Among 17 patients who maintained preoperative sexual activity (Sexual Health Inventory for Men ≥ 17), stage below pT2, followed up for > 6 months with minimally one side of neurovascular bundle preservation procedure, 12 (70.6%) were capable of intercourse postoperatively, and the mean time for sexual intercourse after operation was 5.7 months. In this series, robotic prostatectomy was a feasible and reproducible technique, with a short learning curve and low perioperative complication rate. Even during the initial phase of the learning curve, satisfactory results were obtained with regard to functional and oncological outcome.%为了评价学习曲线中机器人辅助腹腔镜检查根治前列腺切除术(robot-assisted laparoscopic radical prostatectomy,RALRP)的短期结果,即外科、肿瘤学和功能性结果,我们进行了一个关于RALRP的前瞻性调查.从2007年7月开始,一名外科医生运用

  19. Can a virtual reality surgical simulation training provide a self-driven and mentor-free skills learning? Investigation of the practical influence of the performance metrics from the virtual reality robotic surgery simulator on the skill learning and associated cognitive workloads.

    Science.gov (United States)

    Lee, Gyusung I; Lee, Mija R

    2017-06-20

    While it is often claimed that virtual reality (VR) training system can offer self-directed and mentor-free skill learning using the system's performance metrics (PM), no studies have yet provided evidence-based confirmation. This experimental study investigated what extent to which trainees achieved their self-learning with a current VR simulator and whether additional mentoring improved skill learning, skill transfer and cognitive workloads in robotic surgery simulation training. Thirty-two surgical trainees were randomly assigned to either the Control-Group (CG) or Experiment-Group (EG). While the CG participants reviewed the PM at their discretion, the EG participants had explanations about PM and instructions on how to improve scores. Each subject completed a 5-week training using four simulation tasks. Pre- and post-training data were collected using both a simulator and robot. Peri-training data were collected after each session. Skill learning, time spent on PM (TPM), and cognitive workloads were compared between groups. After the simulation training, CG showed substantially lower simulation task scores (82.9 ± 6.0) compared with EG (93.2 ± 4.8). Both groups demonstrated improved physical model tasks performance with the actual robot, but the EG had a greater improvement in two tasks. The EG exhibited lower global mental workload/distress, higher engagement, and a better understanding regarding using PM to improve performance. The EG's TPM was initially long but substantially shortened as the group became familiar with PM. Our study demonstrated that the current VR simulator offered limited self-skill learning and additional mentoring still played an important role in improving the robotic surgery simulation training.

  20. Equations of hyperelliptic Shimura curves

    CERN Document Server

    Molina, Santiago

    2010-01-01

    We describe an algorithm that computes explicit models of hyperelliptic Shimura curves attached to an indefnite quaternion algebra over Q and Atkin-Lehner quotients of them. It exploits Cerednik-Drinfeld's non-archimedean uniformisation of Shimura curves, a formula of Gross and Zagier for the endomorphism ring of Heegner points over Artinian rings and the connection between Ribet's bimodules and the specialization of Heegner points. As an application, we provide a list of equations of Shimura curves and quotients of them obtained by our algorithm that had been conjectured by Kurihara.

  1. Poiseuille flow in curved spaces

    CERN Document Server

    Debus, J -D; Succi, S; Herrmann, H J

    2015-01-01

    We investigate Poiseuille channel flow through intrinsically curved (campylotic) media, equipped with localized metric perturbations (campylons). To this end, we study the flux of a fluid driven through the curved channel in dependence of the spatial deformation, characterized by the campylon parameters (amplitude, range and density). We find that the flux depends only on a specific combination of campylon parameters, which we identify as the average campylon strength, and derive a universal flux law for the Poiseuille flow. For the purpose of this study, we have improved and validated our recently developed lattice Boltzmann model in curved space by considerably reducing discrete lattice effects.

  2. Feature classification for tracking articulated surgical tools.

    Science.gov (United States)

    Reiter, Austin; Allen, Peter K; Zhao, Tao

    2012-01-01

    Tool tracking is an accepted capability for computer-aided surgical intervention which has numerous applications, both in robotic and manual minimally-invasive procedures. In this paper, we describe a tracking system which learns visual feature descriptors as class-specific landmarks on an articulated tool. The features are localized in 3D using stereo vision and are fused with the robot kinematics to track all of the joints of the dexterous manipulator. Experiments are performed using previously-collected porcine data from a surgical robot.

  3. A clarity clinic for surgical writing.

    Science.gov (United States)

    Derish, Pamela; Eastwood, Susan

    2008-06-01

    Although writing and publishing are key to career development and academic success for surgeons, learning the skills needed to write publishable research reports is an often neglected aspect of surgical training. This report distills several lessons from scientific writing courses for surgeons taught at the University of California, San Francisco, to give a wider audience of academic surgeons tools they can use to write scientific prose more clearly. Drawing extensively on real examples of surgical writing, we cover techniques that are indispensable for achieving clarity, including choosing words carefully, designing well-constructed sentences, building structured paragraphs, and displaying your thinking clearly by using topic sentences and transitions.

  4. Training for endoscopic surgical procedures should be performed in the dissection room: a randomized study.

    Science.gov (United States)

    Klitsie, Pieter J; Ten Brinke, Bart; Timman, Reinier; Busschbach, Jan J V; Theeuwes, Hilco P; Lange, Johan F; Kleinrensink, Gert-Jan

    2017-04-01

    Laparoscopic surgery is associated with a shallow learning curve. AnubiFiX embalming technique enables laparoscopic surgical training on supple embalmed and hence insufflatable human specimens in the dissection room. Aim of the present trial is to test whether dissection-based anatomy education is superior to classical frontal classroom education on the short and long term. A total of 112 medical students were randomized in three groups. Group I attended classroom education, group II laparoscopic dissection-based education and group III received both. All groups completed an anatomy test on human specimens before, immediately after and 3 weeks after the anatomy training. Group II and III scored significantly better compared to group I immediately after the anatomy training (p I-II superior outcomes on the short and long term, as compared to classical frontal classroom education.

  5. Description of dose response curve

    OpenAIRE

    Al-Samarai, Firas

    2011-01-01

    The book included several methods to estimate LD50, in addition to explain how to use several programs to estimate LD50. Moreover the book illustrate the description of the dose response curves. Firas Al-Samarai

  6. Normal origamis of Mumford curves

    CERN Document Server

    Kremer, Karsten

    2010-01-01

    An origami (also known as square-tiled surface) is a Riemann surface covering a torus with at most one branch point. Lifting two generators of the fundamental group of the punctured torus decomposes the surface into finitely many unit squares. By varying the complex structure of the torus one obtains easily accessible examples of Teichm\\"uller curves in the moduli space of Riemann surfaces. The p-adic analogues of Riemann surfaces are Mumford curves. A p-adic origami is defined as a covering of Mumford curves with at most one branch point, where the bottom curve has genus one. A classification of all normal non-trivial p-adic origamis is presented and used to calculate some invariants. These can be used to describe p-adic origamis in terms of glueing squares.

  7. Learning

    Directory of Open Access Journals (Sweden)

    Mohsen Laabidi

    2014-01-01

    Full Text Available Nowadays learning technologies transformed educational systems with impressive progress of Information and Communication Technologies (ICT. Furthermore, when these technologies are available, affordable and accessible, they represent more than a transformation for people with disabilities. They represent real opportunities with access to an inclusive education and help to overcome the obstacles they met in classical educational systems. In this paper, we will cover basic concepts of e-accessibility, universal design and assistive technologies, with a special focus on accessible e-learning systems. Then, we will present recent research works conducted in our research Laboratory LaTICE toward the development of an accessible online learning environment for persons with disabilities from the design and specification step to the implementation. We will present, in particular, the accessible version “MoodleAcc+” of the well known e-learning platform Moodle as well as new elaborated generic models and a range of tools for authoring and evaluating accessible educational content.

  8. String networks as tropical curves

    CERN Document Server

    Ray, Koushik

    2008-01-01

    A prescription for obtaining supergravity solutions for planar (p,q)-string networks is presented, based on earlier results. It shows that networks may be looked upon as tropical curves emerging as the spine of the amoeba of a holomorphic curve in M-theory. The Kaehler potential of supergravity is identified with the corresponding Ronkin function. Implications of this identification in counting dyons is discussed.

  9. Growth curves for Laron syndrome.

    OpenAIRE

    Laron, Z; Lilos, P; Klinger, B.

    1993-01-01

    Growth curves for children with Laron syndrome were constructed on the basis of repeated measurements made throughout infancy, childhood, and puberty in 24 (10 boys, 14 girls) of the 41 patients with this syndrome investigated in our clinic. Growth retardation was already noted at birth, the birth length ranging from 42 to 46 cm in the 12/20 available measurements. The postnatal growth curves deviated sharply from the normal from infancy on. Both sexes showed no clear pubertal spurt. Girls co...

  10. Flow over riblet curved surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Loureiro, J B R; Freire, A P Silva, E-mail: atila@mecanica.ufrj.br [Mechanical Engineering Program, Federal University of Rio de Janeiro (COPPE/UFRJ), C.P. 68503, 21.941-972, Rio de Janeiro, RJ (Brazil)

    2011-12-22

    The present work studies the mechanics of turbulent drag reduction over curved surfaces by riblets. The effects of surface modification on flow separation over steep and smooth curved surfaces are investigated. Four types of two-dimensional surfaces are studied based on the morphometric parameters that describe the body of a blue whale. Local measurements of mean velocity and turbulence profiles are obtained through laser Doppler anemometry (LDA) and particle image velocimetry (PIV).

  11. Impact of prone surgical positioning on the scoliotic spine.

    Science.gov (United States)

    Driscoll, Christopher Robert; Aubin, Carl-Éric; Canet, Fanny; Labelle, Hubert; Dansereau, Jean

    2012-05-01

    To study the impact of patient-specific prone positioning on the sagittal and coronal curves of scoliotic spines, including the impact of various patient and surgical frame factors. Prone operative positioning has been shown to impact the geometry of various individual spinal segments. Its impact on global spinal geometry and influential factors remains unknown. Lateral and coronal radiographs were acquired of 6 scoliotic patients while standing, prone on a dynamically adjustable surgical frame and intraoperatively on the Relton-Hall frame. Standing lateral bending radiographs were also acquired. Lordosis, kyphosis, and Cobb angles were measured in each position. Personalized finite element models (FEMs), including the spine, ribcage, pelvis, and lower limbs were generated for each patient based on their standing radiographs. The FEM's ability to reproduce prone spinal geometry was evaluated by using different values of intervertebral disc elastic moduli: published, optimized based on lateral bending radiographs and optimized based on prone radiographs. The 6 FEMs were then exploited to study the impact of surgical frame cushion configuration, standing curve magnitudes, and patient weight on spinal geometry changes due to prone positioning. All coronal and sagittal curves decreased in the prone position; averaging 12% in lordosis, 19% in kyphosis, 7%, 14%, and 26%, respectively, for proximal thoracic, main thoracic, and thoracolumbar/lumbar Cobb angles. FEM prone simulations yielded best results when optimized by using the prone position radiographs (Δ<5 degrees for all segmental curves). Lateral bending optimization yielded similar results by using published properties. Surgical frame cushion configuration, standing curve magnitudes, and patient weight all had an important impact on spinal geometries with the exception of thoracic cushion longitudinal position. A strong correlation (R=0.86) was found between standing kyphosis and its reduction in the prone

  12. Linear Systems on Tropical Curves

    CERN Document Server

    Haase, Christian; Yu, Josephine

    2009-01-01

    A tropical curve \\Gamma is a metric graph with possibly unbounded edges, and tropical rational functions are continuous piecewise linear functions with integer slopes. We define the complete linear system |D| of a divisor D on a tropical curve \\Gamma analogously to the classical counterpart. We investigate the structure of |D| as a cell complex and show that linear systems are quotients of tropical modules, finitely generated by vertices of the cell complex. Using a finite set of generators, |D| defines a map from \\Gamma to a tropical projective space, and the image can be extended to a tropical curve of degree equal to \\deg(D). The tropical convex hull of the image realizes the linear system |D| as a polyhedral complex. We show that curves for which the canonical divisor is not very ample are hyperelliptic. We also show that the Picard group of a \\Q-tropical curve is a direct limit of critical groups of finite graphs converging to the curve.

  13. Mary Boole and curve stitching: a look into heaven.

    Science.gov (United States)

    Innes, Shelley

    2004-03-01

    Mary Everest Boole had a lifelong interest in the unconscious mind, the psychology of learning, and how these relate to the teaching of mathematics and science. She recommended many practical exercises and teaching aids, one of which was the technique of curve stitching, which she had invented while still a child herself.

  14. Spaghetti Sine Curves: Virtual Environments for Reasoning and Sense Making

    Science.gov (United States)

    Özgün-Koca, S. Asli; Edwards, Michael Todd; Meagher, Michael

    2013-01-01

    In a recent collaboration with an area high school teacher, the authors were asked to develop an introductory sinusoidal curves lesson for a group of second-year algebra students. Because the topic was abstract and unfamiliar to these tenth graders, they looked for hands-on lessons to support their learning. One lesson that they found, which they…

  15. How Graphing Calculators Find Curves of Best Fit

    Science.gov (United States)

    Shore, Mark; Shore, JoAnna; Boggs, Stacey

    2004-01-01

    For over a decade mathematics instructors have been using graphing calculators in courses ranging from developmental mathematics (Beginning and Intermediate Algebra) to Calculus and Statistics. One of the key functions that make them so powerful in the teaching and learning process is their ability to find curves of best fit. Instructors may use…

  16. Surgical ethics: surgical virtue and more.

    Science.gov (United States)

    Vercler, Christian J

    2015-01-01

    The encounter between a patient and her surgeon is unique for several reasons. The surgeon inflicts pain upon a patient for the patient's own good. An operative intervention is irreducibly personal, such that the decisions about and performance of operations are inseparable from the idiosyncrasies of the individual surgeon. Furthermore, there is a chasm of knowledge between the patient and surgeon that is difficult to cross. Hence, training in the discipline of surgery includes the inculcation of certain virtues and practices to safeguard against abuses of this relationship and to make sure that the best interests of the patient are prioritized. The stories in this issue are evidence that in contemporary practice this is not quite enough, as surgeons reflect on instances they felt were ethically challenging. Common themes include the difficulty in communicating surgical uncertainty, patient-surgeon relationships, ethical issues in surgical training, and the impact of the technological imperative on caring for dying patients.

  17. Multiscale Surgical Telerobots

    Energy Technology Data Exchange (ETDEWEB)

    Miles, R R; Seward, K P; Benett, W J; Tendick, F; Bentley, L; Stephan, P L

    2002-01-23

    A project was undertaken to improve robotic surgical tools for telerobotic minimally invasive surgery. The major objectives were to reduce the size of the tools to permit new surgical procedures in confined spaces such as the heart and to improve control of surgical tools by locating positional sensors and actuators at the end effector rather than external to the patient as is currently the state of the technology. A new compact end-effector with wrist-like flexibility was designed. Positional sensors based on MEMS microfabrication techniques were designed.

  18. The Da Vinci Xi and robotic radical prostatectomy-an evolution in learning and technique.

    Science.gov (United States)

    Goonewardene, S S; Cahill, D

    2016-08-19

    The da Vinci Xi robot has been introduced as the successor to the Si platform. The promise of the Xi is to open the door to new surgical procedures. For robotic-assisted radical prostatectomy (RARP)/pelvic surgery, the potential is better vision and longer instruments. How has the Xi impacted on operative and pathological parameters as indicators of surgical performance? This is a comparison of an initial series of 42 RARPs with the Xi system in 2015 with a series using the Si system immediately before Xi uptake in the same calendar year, and an Si series by the same surgeon synchronously as the Xi series using operative time, blood loss, and positive margins as surrogates of surgical performance. Subjectively and objectively, there is a learning curve to Xi uptake in longer operative times but no impact on T2 positive margins which are the most reflective single measure of RARP outcomes. Subjectively, the vision of the Xi is inferior to the Si system, and the integrated diathermy system and automated setup are quirky. All require experience to overcome. There is a learning curve to progress from the Si to Xi da Vinci surgical platforms, but this does not negatively impact the outcome.

  19. Playing off the curve - testing quantitative predictions of skill acquisition theories in development of chess performance.

    Science.gov (United States)

    Gaschler, Robert; Progscha, Johanna; Smallbone, Kieran; Ram, Nilam; Bilalić, Merim

    2014-01-01

    Learning curves have been proposed as an adequate description of learning processes, no matter whether the processes manifest within minutes or across years. Different mechanisms underlying skill acquisition can lead to differences in the shape of learning curves. In the current study, we analyze the tournament performance data of 1383 chess players who begin competing at young age and play tournaments for at least 10 years. We analyze the performance development with the goal to test the adequacy of learning curves, and the skill acquisition theories they are based on, for describing and predicting expertise acquisition. On the one hand, we show that the skill acquisition theories implying a negative exponential learning curve do a better job in both describing early performance gains and predicting later trajectories of chess performance than those theories implying a power function learning curve. On the other hand, the learning curves of a large proportion of players show systematic qualitative deviations from the predictions of either type of skill acquisition theory. While skill acquisition theories predict larger performance gains in early years and smaller gains in later years, a substantial number of players begin to show substantial improvements with a delay of several years (and no improvement in the first years), deviations not fully accounted for by quantity of practice. The current work adds to the debate on how learning processes on a small time scale combine to large-scale changes.

  20. New symmetry of intended curved reaches

    Directory of Open Access Journals (Sweden)

    Torres Elizabeth B

    2010-04-01

    Full Text Available Abstract Background Movement regularities are inherently present in automated goal-directed motions of the primate's arm system. They can provide important signatures of intentional behaviours driven by sensory-motor strategies, but it remains unknown if during motor learning new regularities can be uncovered despite high variability in the temporal dynamics of the hand motions. Methods We investigated the conservation and violation of new movement regularity obtained from the hand motions traced by two untrained monkeys as they learned to reach outwardly towards spatial targets while avoiding obstacles in the dark. The regularity pertains to the transformation from postural to hand paths that aim at visual goals. Results In length-minimizing curves the area enclosed between the Euclidean straight line and the curve up to its point of maximum curvature is 1/2 of the total area. Similar trend is found if one examines the perimeter. This new movement regularity remained robust to striking changes in arm dynamics that gave rise to changes in the speed of the reach, to changes in the hand path curvature, and to changes in the arm's postural paths. The area and perimeter ratios characterizing the regularity co-varied across repeats of randomly presented targets whenever the transformation from posture to hand paths was compliant with the intended goals. To interpret this conservation and the cases in which the regularity was violated and recovered, we provide a geometric model that characterizes arm-to-hand and hand-to-arm motion paths as length minimizing curves (geodesics in a non-Euclidean space. Whenever the transformation from one space to the other is distance-metric preserving (isometric the two symmetric ratios co-vary. Otherwise, the symmetric ratios and their co-variation are violated. As predicted by the model we found empirical evidence for the violation of this movement regularity whenever the intended goals mismatched the actions. This

  1. Guide to Surgical Specialists

    Science.gov (United States)

    ... have expertise in the following areas of responsibility: neonatal surgery (specialized knowledge in the surgical repair of ... and non-operative management of certain types of pain. Common conditions managed by neurologic surgeons include disorders ...

  2. Surgical Critical Care Initiative

    Data.gov (United States)

    Federal Laboratory Consortium — The Surgical Critical Care Initiative (SC2i) is a USU research program established in October 2013 to develop, translate, and validate biology-driven critical care....

  3. Ambulatory Surgical Measures - National

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Ambulatory Surgical Center Quality Reporting (ASCQR) Program seeks to make care safer and more efficient through quality reporting. ASCs eligible for this...

  4. Ambulatory Surgical Measures - Facility

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Ambulatory Surgical Center Quality Reporting (ASCQR) Program seeks to make care safer and more efficient through quality reporting. ASCs eligible for this...

  5. Surgical site infections

    African Journals Online (AJOL)

    and mortality as well as significant financial implications. Worldwide it has ... common nosocomial infection amongst surgical patients with up to 38% .... antibiotics as soon as the sensitivity results are available. ... Breast surgery. Staph Aureus/ ...

  6. Curve Digitizer – A software for multiple curves digitizing

    Directory of Open Access Journals (Sweden)

    Florentin ŞPERLEA

    2010-06-01

    Full Text Available The Curve Digitizer is software that extracts data from an image file representing a graphicand returns them as pairs of numbers which can then be used for further analysis and applications.Numbers can be read on a computer screen stored in files or copied on paper. The final result is adata set that can be used with other tools such as MSEXCEL. Curve Digitizer provides a useful toolfor any researcher or engineer interested in quantifying the data displayed graphically. The image filecan be obtained by scanning a document

  7. Surgical advantages of reduced-port laparoscopic gastrectomy in gastric cancer.

    Science.gov (United States)

    Kunisaki, Chikara; Makino, Hirochika; Yamaguchi, Naotaka; Izumisawa, Yusuke; Miyamato, Hiroshi; Sato, Kei; Hayashi, Tsutomu; Sugano, Nobuhiro; Suzuki, Yoshihiro; Ota, Mitsuyoshi; Tsuburaya, Akira; Kimura, Jun; Takagawa, Ryo; Kosaka, Takashi; Ono, Hidetaka Andrew; Akiyama, Hirotoshi; Endo, Itaru

    2016-12-01

    Although a few studies have reported the use of reduced-port laparoscopic gastrectomy (RPG) in gastric cancer patients, the feasibility of routinely using this technique remains unclear. It is therefore important to evaluate the surgical advantages of this technique in this patient group. Between August 2010 and July 2015, 165 patients underwent RPGs at our hospital, performed by a single surgeon. Of these patients, 88 underwent reduced-port laparoscopic distal gastrectomy (RPLDG) and 77 underwent reduced-port laparoscopic total gastrectomy (RPLTG). In addition to short-term surgical outcomes after RPG, survival times and the surgical learning curve were also evaluated. Blood losses during lymph node dissection in the RPLDG and RPLTG groups were not significantly different (p = 0.160). Conversion to open surgery was necessary in only two patients. Postoperative morbidities were observed in 14.8 % of the RPLDG group and 14.3 % of the RPLTG group, but there were no deaths. Most patients expressed high cosmetic satisfaction in both groups. In the RPLDG group, operation time during reconstruction decreased over the first 50 cases and then plateaued, as the surgeon's experience of the technique increased. In contrast, in the RPLTG group, operation times dropped with surgical experience for both lymph node dissection, plateauing after 40 cases, and for reconstruction, plateauing after 30 cases. Only three patients died of gastric cancer in the follow-up period and three patients died of other diseases. Five-year overall survival and 5-year disease-specific survival were 95.6 and 98.0 %, respectively. We have shown that reduced-port gastrectomy (RPG) could be an acceptable and satisfactory procedure for treating gastric cancer for an experienced laparoscopic gastric surgeon who has sufficient previous experience of conventional laparoscopic gastrectomies.

  8. Minimal invasive surgical correction of pectus excavatum deformities in adolescents: Our institutional experience

    Directory of Open Access Journals (Sweden)

    Jokić Radoica

    2013-01-01

    Full Text Available Introduction. Nuss procedure is a minimal invasive surgical technique based on retrosternal placement of a metal plate to correct pectus excavatum chest deformity. We are presenting our five­year (2006­2011 institutional experience of 21 patients. Objective. The aim of this study was to determine characteristics and advantages of minimal invasive surgical approach in correcting deformities of the chest. Methods. Surgical procedure, named after its author Nuss, involves the surgical placement of a molded metal plate, the so­called pectus bar, behind the sternum under thoracoscopic view whereby immediate controlled intraoperative corrections and stabilizations of the depression can be made. The great advantage of this method is reflected in a significant shortening of operative time, usually without indications for compensation in blood volume, and with a significantly shortened postoperative recovery that allows patients to quickly return to their normal activities. Results. In the period 2006­2011, 21 patients were operated by the Nuss procedure. The pectus bar was set in front or behind the muscles of the chest. Among the complications listed were inflammation of wounds in three patients, dislocation (shifting of the bar requiring a reoperation in two patients, an occurrence of a pericardial effusion in one patient, and allergic response to foreign body in one patient. Five patients required extraction of the bar two years later, and three patients after three years, all with excellent results. Conclusion. Minimally invasive Nuss procedure is safe and effective. It currently represents the primary method of choice for solving the chest deformity pectus excavatum for patients of all ages. Modification of thoracoscopic control allows a safe field of operation. Postoperative results are excellent with very few complications that can be attributed to the learning curve.

  9. 3D-printed pediatric endoscopic ear surgery simulator for surgical training.

    Science.gov (United States)

    Barber, Samuel R; Kozin, Elliott D; Dedmon, Matthew; Lin, Brian M; Lee, Kyuwon; Sinha, Sumi; Black, Nicole; Remenschneider, Aaron K; Lee, Daniel J

    2016-11-01

    Surgical simulators are designed to improve operative skills and patient safety. Transcanal Endoscopic Ear Surgery (TEES) is a relatively new surgical approach with a slow learning curve due to one-handed dissection. A reusable and customizable 3-dimensional (3D)-printed endoscopic ear surgery simulator may facilitate the development of surgical skills with high fidelity and low cost. Herein, we aim to design, fabricate, and test a low-cost and reusable 3D-printed TEES simulator. The TEES simulator was designed in computer-aided design (CAD) software using anatomic measurements taken from anthropometric studies. Cross sections from external auditory canal samples were traced as vectors and serially combined into a mesh construct. A modified tympanic cavity with a modular testing platform for simulator tasks was incorporated. Components were fabricated using calcium sulfate hemihydrate powder and multiple colored infiltrants via a commercial inkjet 3D-printing service. All components of a left-sided ear were printed to scale. Six right-handed trainees completed three trials each. Mean trial time (n = 3) ranged from 23.03 to 62.77 s using the dominant hand for all dissection. Statistically significant differences between first and last completion time with the dominant hand (p < 0.05) and average completion time for junior and senior residents (p < 0.05) suggest construct validity. A 3D-printed simulator is feasible for TEES simulation. Otolaryngology training programs with access to a 3D printer may readily fabricate a TEES simulator, resulting in inexpensive yet high-fidelity surgical simulation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. Groin hernia: anatomical and surgical history.

    Science.gov (United States)

    McClusky, David A; Mirilas, Petros; Zoras, Odysseas; Skandalakis, Panagiotis N; Skandalakis, John E

    2006-10-01

    The history of surgical repair of groin hernia is a lengthy record of assorted techniques in search of a cure for an ailment that comes in many sizes and shapes and that has plagued humanity for thousands of years. Although improvements are still being sought and found, for several decades surgeons have had the means to relieve most hernia sufferers. A remaining issue is whether the wide array of surgical procedures can or should be whittled down to a few "standard" operations that are safe, effective, and cost-efficient. The history of the anatomy of groin hernia shows how much there was to learn and how much remains to be learned. It also shows how important it is for the surgeon to know and understand both the anatomy of the area and the formation of groin hernia.

  11. Topological recursion and mirror curves

    CERN Document Server

    Bouchard, Vincent

    2012-01-01

    We study the constant contributions to the free energies obtained through the topological recursion applied to the complex curves mirror to toric Calabi-Yau threefolds. We show that the recursion reproduces precisely the corresponding Gromov-Witten invariants, which can be encoded in powers of the MacMahon function. As a result, we extend the scope of the "remodeling conjecture" to the full free energies, including the constant contributions. In the process we study how the pair of pants decomposition of the mirror curves plays an important role in the topological recursion. We also show that the free energies are not, strictly speaking, symplectic invariants, and that the recursive construction of the free energies does not commute with certain limits of mirror curves.

  12. Laffer Curves and Home Production

    Directory of Open Access Journals (Sweden)

    Kotamäki Mauri

    2017-06-01

    Full Text Available In the earlier related literature, consumption tax rate Laffer curve is found to be strictly increasing (see Trabandt and Uhlig (2011. In this paper, a general equilibrium macro model is augmented by introducing a substitute for private consumption in the form of home production. The introduction of home production brings about an additional margin of adjustment – an increase in consumption tax rate not only decreases labor supply and reduces the consumption tax base but also allows a substitution of market goods with home-produced goods. The main objective of this paper is to show that, after the introduction of home production, the consumption tax Laffer curve exhibits an inverse U-shape. Also the income tax Laffer curves are significantly altered. The result shown in this paper casts doubt on some of the earlier results in the literature.

  13. Canonical curves with low apolarity

    CERN Document Server

    Ballico, Edoardo; Notari, Roberto

    2010-01-01

    Let $k$ be an algebraically closed field and let $C$ be a non--hyperelliptic smooth projective curve of genus $g$ defined over $k$. Since the canonical model of $C$ is arithmetically Gorenstein, Macaulay's theory of inverse systems allows to associate to $C$ a cubic form $f$ in the divided power $k$--algebra $R$ in $g-2$ variables. The apolarity of $C$ is the minimal number $t$ of linear form in $R$ needed to write $f$ as sum of their divided power cubes. It is easy to see that the apolarity of $C$ is at least $g-2$ and P. De Poi and F. Zucconi classified curves with apolarity $g-2$ when $k$ is the complex field. In this paper, we give a complete, characteristic free, classification of curves $C$ with apolarity $g-1$ (and $g-2$).

  14. Curved spacetimes in the lab

    CERN Document Server

    Szpak, Nikodem

    2014-01-01

    We present some new ideas on how to design analogue models of quantum fields living in curved spacetimes using ultra-cold atoms in optical lattices. We discuss various types of static and dynamical curved spacetimes achievable by simple manipulations of the optical setup. Examples presented here contain two-dimensional spaces of positive and negative curvature as well as homogeneous cosmological models and metric waves. Most of them are extendable to three spatial dimensions. We mention some interesting phenomena of quantum field theory in curved spacetimes which might be simulated in such optical lattices loaded with bosonic or fermionic ultra-cold atoms. We also argue that methods of differential geometry can be used, as an alternative mathematical approach, for dealing with realistic inhomogeneous optical lattices.

  15. Algebraic curves of maximal cyclicity

    Science.gov (United States)

    Caubergh, Magdalena; Dumortier, Freddy

    2006-01-01

    The paper deals with analytic families of planar vector fields, studying methods to detect the cyclicity of a non-isolated closed orbit, i.e. the maximum number of limit cycles that can locally bifurcate from it. It is known that this multi-parameter problem can be reduced to a single-parameter one, in the sense that there exist analytic curves in parameter space along which the maximal cyclicity can be attained. In that case one speaks about a maximal cyclicity curve (mcc) in case only the number is considered and of a maximal multiplicity curve (mmc) in case the multiplicity is also taken into account. In view of obtaining efficient algorithms for detecting the cyclicity, we investigate whether such mcc or mmc can be algebraic or even linear depending on certain general properties of the families or of their associated Bautin ideal. In any case by well chosen examples we show that prudence is appropriate.

  16. ToolNet: Holistically-Nested Real-Time Segmentation of Robotic Surgical Tools

    OpenAIRE

    Garcia-Peraza-Herrera, Luis C.; Li, Wenqi; Fidon, Lucas; Gruijthuijsen, Caspar; Devreker, Alain; Attilakos, George; Deprest, Jan; Poorten, Emmanuel Vander; Stoyanov, Danail; Vercauteren, Tom; Ourselin, Sebastien

    2017-01-01

    Real-time tool segmentation from endoscopic videos is an essential part of many computer-assisted robotic surgical systems and of critical importance in robotic surgical data science. We propose two novel deep learning architectures for automatic segmentation of non-rigid surgical instruments. Both methods take advantage of automated deep-learning-based multi-scale feature extraction while trying to maintain an accurate segmentation quality at all resolutions. The two proposed methods encode ...

  17. Aspects of computer vision in surgical endoscopy

    Science.gov (United States)

    Rodin, Vincent; Ayache, Alain; Berreni, N.

    1993-09-01

    This work is related to a project of medical robotics applied to surgical endoscopy, led in collaboration with Doctor Berreni from the Saint Roch nursing-home in Perpignan, France). After taking what Doctor Berreni advises, two aspects of endoscopic color image processing have been brought out: (1) The help to the diagnosis by the automatic detection of the sick areas after a learning phase. (2) The 3D reconstruction of the analyzed cavity by using a zoom.

  18. Shock detachment from curved wedges

    Science.gov (United States)

    Mölder, S.

    2017-03-01

    Curved shock theory is used to show that the flow behind attached shocks on doubly curved wedges can have either positive or negative post-shock pressure gradients depending on the freestream Mach number, the wedge angle and the two wedge curvatures. Given enough wedge length, the flow near the leading edge can choke to force the shock to detach from the wedge. This local choking can preempt both the maximum deflection and the sonic criteria for shock detachment. Analytical predictions for detachment by local choking are supported by CFD results.

  19. Shock detachment from curved wedges

    Science.gov (United States)

    Mölder, S.

    2017-09-01

    Curved shock theory is used to show that the flow behind attached shocks on doubly curved wedges can have either positive or negative post-shock pressure gradients depending on the freestream Mach number, the wedge angle and the two wedge curvatures. Given enough wedge length, the flow near the leading edge can choke to force the shock to detach from the wedge. This local choking can preempt both the maximum deflection and the sonic criteria for shock detachment. Analytical predictions for detachment by local choking are supported by CFD results.

  20. Caloric Curves and Nuclear Expansion

    CERN Document Server

    Natowitz, J B; Ma, Y; Murray, M; Qin, L; Shlomo, S; Wada, R; Wang, J

    2002-01-01

    Nuclear caloric curves have been analyzed using an expanding Fermi gas hypothesis to extract average nuclear densities. In this approach the observed flattening of the caloric curves reflects progressively increasing expansion with increasing excitation energy. This expansion results in a corresponding decrease in the density and Fermi energy of the excited system. For nuclei of medium to heavy mass apparent densities $~0.3\\rho_0$ are reached at the higher excitation energies. The average densities derived in this manner are in good agreement with those derived using other, more complicated, techniques.

  1. Curved branes with regular support

    Energy Technology Data Exchange (ETDEWEB)

    Antoniadis, Ignatios [Sorbonne Universites, LPTHE, UMR CNRS 7589, Paris (France); University of Bern, Albert Einstein Center for Fundamental Physics, ITP, Bern (Switzerland); Cotsakis, Spiros; Klaoudatou, Ifigeneia [American University of the Middle East, Department of Mathematics, P. O. Box 220, Dasman (Kuwait)

    2016-09-15

    We study spacetime singularities in a general five-dimensional braneworld with curved branes satisfying four-dimensional maximal symmetry. The bulk is supported by an analog of perfect fluid with the time replaced by the extra coordinate. We show that contrary to the existence of finite-distance singularities from the brane location in any solution with flat (Minkowski) branes, in the case of curved branes there are singularity-free solutions for a range of equations of state compatible with the null energy condition. (orig.)

  2. 3D Surgical Simulation

    Science.gov (United States)

    Cevidanes, Lucia; Tucker, Scott; Styner, Martin; Kim, Hyungmin; Chapuis, Jonas; Reyes, Mauricio; Proffit, William; Turvey, Timothy; Jaskolka, Michael

    2009-01-01

    This paper discusses the development of methods for computer-aided jaw surgery. Computer-aided jaw surgery allows us to incorporate the high level of precision necessary for transferring virtual plans into the operating room. We also present a complete computer-aided surgery (CAS) system developed in close collaboration with surgeons. Surgery planning and simulation include construction of 3D surface models from Cone-beam CT (CBCT), dynamic cephalometry, semi-automatic mirroring, interactive cutting of bone and bony segment repositioning. A virtual setup can be used to manufacture positioning splints for intra-operative guidance. The system provides further intra-operative assistance with the help of a computer display showing jaw positions and 3D positioning guides updated in real-time during the surgical procedure. The CAS system aids in dealing with complex cases with benefits for the patient, with surgical practice, and for orthodontic finishing. Advanced software tools for diagnosis and treatment planning allow preparation of detailed operative plans, osteotomy repositioning, bone reconstructions, surgical resident training and assessing the difficulties of the surgical procedures prior to the surgery. CAS has the potential to make the elaboration of the surgical plan a more flexible process, increase the level of detail and accuracy of the plan, yield higher operative precision and control, and enhance documentation of cases. Supported by NIDCR DE017727, and DE018962 PMID:20816308

  3. Interpolation and Polynomial Curve Fitting

    Science.gov (United States)

    Yang, Yajun; Gordon, Sheldon P.

    2014-01-01

    Two points determine a line. Three noncollinear points determine a quadratic function. Four points that do not lie on a lower-degree polynomial curve determine a cubic function. In general, n + 1 points uniquely determine a polynomial of degree n, presuming that they do not fall onto a polynomial of lower degree. The process of finding such a…

  4. Principal Curves on Riemannian Manifolds.

    Science.gov (United States)

    Hauberg, Soren

    2016-09-01

    Euclidean statistics are often generalized to Riemannian manifolds by replacing straight-line interpolations with geodesic ones. While these Riemannian models are familiar-looking, they are restricted by the inflexibility of geodesics, and they rely on constructions which are optimal only in Euclidean domains. We consider extensions of Principal Component Analysis (PCA) to Riemannian manifolds. Classic Riemannian approaches seek a geodesic curve passing through the mean that optimizes a criteria of interest. The requirements that the solution both is geodesic and must pass through the mean tend to imply that the methods only work well when the manifold is mostly flat within the support of the generating distribution. We argue that instead of generalizing linear Euclidean models, it is more fruitful to generalize non-linear Euclidean models. Specifically, we extend the classic Principal Curves from Hastie & Stuetzle to data residing on a complete Riemannian manifold. We show that for elliptical distributions in the tangent of spaces of constant curvature, the standard principal geodesic is a principal curve. The proposed model is simple to compute and avoids many of the pitfalls of traditional geodesic approaches. We empirically demonstrate the effectiveness of the Riemannian principal curves on several manifolds and datasets.

  5. Variability among polysulphone calibration curves

    Energy Technology Data Exchange (ETDEWEB)

    Casale, G R [University of Rome ' La Sapienza' , Physics Department, P.le A. Moro 2, I-00185, Rome (Italy); Borra, M [ISPESL - Istituto Superiore per la Prevenzione E la Sicurezza del Lavoro, Occupational Hygiene Department, Via Fontana Candida 1, I-0040 Monteporzio Catone (RM) (Italy); Colosimo, A [University of Rome ' La Sapienza' , Department of Human Physiology and Pharmacology, P.le A. Moro 2, I-00185, Rome (Italy); Colucci, M [ISPESL - Istituto Superiore per la Prevenzione E la Sicurezza del Lavoro, Occupational Hygiene Department, Via Fontana Candida 1, I-0040 Monteporzio Catone (RM) (Italy); Militello, A [ISPESL - Istituto Superiore per la Prevenzione E la Sicurezza del Lavoro, Occupational Hygiene Department, Via Fontana Candida 1, I-0040 Monteporzio Catone (RM) (Italy); Siani, A M [University of Rome ' La Sapienza' , Physics Department, P.le A. Moro 2, I-00185, Rome (Italy); Sisto, R [ISPESL - Istituto Superiore per la Prevenzione E la Sicurezza del Lavoro, Occupational Hygiene Department, Via Fontana Candida 1, I-0040 Monteporzio Catone (RM) (Italy)

    2006-09-07

    Within an epidemiological study regarding the correlation between skin pathologies and personal ultraviolet (UV) exposure due to solar radiation, 14 field campaigns using polysulphone (PS) dosemeters were carried out at three different Italian sites (urban, semi-rural and rural) in every season of the year. A polysulphone calibration curve for each field experiment was obtained by measuring the ambient UV dose under almost clear sky conditions and the corresponding change in the PS film absorbance, prior and post exposure. Ambient UV doses were measured by well-calibrated broad-band radiometers and by electronic dosemeters. The dose-response relation was represented by the typical best fit to a third-degree polynomial and it was parameterized by a coefficient multiplying a cubic polynomial function. It was observed that the fit curves differed from each other in the coefficient only. It was assessed that the multiplying coefficient was affected by the solar UV spectrum at the Earth's surface whilst the polynomial factor depended on the photoinduced reaction of the polysulphone film. The mismatch between the polysulphone spectral curve and the CIE erythemal action spectrum was responsible for the variability among polysulphone calibration curves. The variability of the coefficient was related to the total ozone amount and the solar zenith angle. A mathematical explanation of such a parameterization was also discussed.

  6. Space curves, anholonomy and nonlinearity

    Indian Academy of Sciences (India)

    Radha Balakrishnan

    2005-04-01

    Using classical differential geometry, we discuss the phenomenon of anholonomy that gets associated with a static and a moving curve. We obtain the expressions for the respective geometric phases in the two cases and interpret them. We show that there is a close connection between anholonomy and nonlinearity in a wide class of nonlinear systems.

  7. The soil reference shrinkage curve

    CERN Document Server

    Chertkov, V Y

    2014-01-01

    A recently proposed model showed how a clay shrinkage curve is transformed to the soil shrinkage curve at the soil clay content higher than a critical one. The objective of the present work was to generalize this model to the soil clay content lower a critical one. I investigated (i) the reference shrinkage curve, that is, one without cracks; (ii) the superficial layer of aggregates, with changed pore structure compared with the intraaggregate matrix; and (iii) soils with sufficiently low clay content where there are large pores inside the intraaggregate clay (so-called lacunar pores). The methodology is based on detail accounting for different contributions to the soil volume and water content during shrinkage. The key point is the calculation of the lacunar pore volume variance at shrinkage. The reference shrinkage curve is determined by eight physical soil parameters: (1) oven-dried specific volume; (2) maximum swelling water content; (3) mean solid density; (4) soil clay content; (5) oven-dried structural...

  8. Surgical Responses of Medial Rectus Muscle Recession in Thyroid Eye Disease-Related Esotropia.

    Directory of Open Access Journals (Sweden)

    In Jeong Lyu

    Full Text Available We evaluate the surgical outcomes and surgical responses of medial rectus muscle (MR recession patients with thyroid eye disease (TED-related esotropia (ET. The surgical dose-response curves 1 week postoperatively and at the final visit were analyzed. Univariable and multivariable linear regression analyses were applied to investigate factors influencing surgical dose-response. A total of 43 patients with TED-related ET that underwent MR recession were included. The final success rate was 86.0% and the rate of undercorrection was 14.0%. The surgical dose-response curves of TED-related ET showed a gentle slope compared with those of standard surgical tables. In the univariable model, simultaneous vertical rectus muscle recession was the only significant factor influencing surgical dose-response of MR recession in TED-related ET (β = -0.397, P = 0.044. In a model adjusted for age, sex, type of surgery, and preoperative horizontal angle of deviation, simultaneous vertical rectus muscle recession showed marginal significance (β = -0.389, P = 0.064. The surgical dose-response curve of TED-related ET was unique. Simultaneous vertical rectus muscle recession was associated with increased surgical dose-response in TED-related ET.

  9. Implementation of a Robotic Surgical Program in Gynaecological Oncology and Comparison with Prior Laparoscopic Series

    Directory of Open Access Journals (Sweden)

    Natalia Povolotskaya

    2015-01-01

    Full Text Available Background. Robotic surgery in gynaecological oncology is a rapidly developing field as it offers several technical advantages over conventional laparoscopy. An audit was performed on the outcome of robotic surgery during our learning curve and compared with recent well-established laparoscopic procedure data. Method. Following acquisition of the da Vinci Surgical System (Intuitive Surgical, Inc., Sunnyvale, California, USA, we prospectively analysed all cases performed over the first six months by one experienced gynaecologist who had been appropriately trained and mentored. Data on age, BMI, pathology, surgery type, blood loss, morbidity, return to theatre, hospital stay, and readmission rate were collected and compared with a consecutive series over the preceding 6 months performed laparoscopically by the same team. Results. A comparison of two consecutive series was made. The mean age was somewhat different, 55 years in the robotic versus 69 years in the laparoscopic group, but obesity was a feature of both groups with a mean of BMI 29.3 versus 28.06, respectively. This difference was not statistically significant (P=0.54. Three subgroups of minimal access surgical procedures were performed: total hysterectomy and bilateral salpingooophorectomy (TH + BSO, total hysterectomy and bilateral salpingooophorectomy plus bilateral pelvic lymphadenectomy (TH + BSO + BPLND, and radical hysterectomy plus bilateral pelvic lymphadenectomy (RH + BPLND. The mean time taken to perform surgery for TH + BSO was longer in the robotic group, 151.2 min compared to 126.3 min in the laparoscopic group. TH + BSO + BPLND surgical time was similar to 178.3 min in robotic group and 176.5 min in laparoscopic group. RH + BPLND surgical time was similar, 263.6 min (robotic arm and 264.0 min (laparoscopic arm. However, the numbers in this initial analysis were small especially in the last two subgroups and do not allow for statistical analysis. The rate of

  10. Implementation of a robotic surgical program in gynaecological oncology and comparison with prior laparoscopic series.

    Science.gov (United States)

    Povolotskaya, Natalia; Woolas, Robert; Brinkmann, Dirk

    2015-01-01

    Robotic surgery in gynaecological oncology is a rapidly developing field as it offers several technical advantages over conventional laparoscopy. An audit was performed on the outcome of robotic surgery during our learning curve and compared with recent well-established laparoscopic procedure data. Following acquisition of the da Vinci Surgical System (Intuitive Surgical, Inc., Sunnyvale, California, USA), we prospectively analysed all cases performed over the first six months by one experienced gynaecologist who had been appropriately trained and mentored. Data on age, BMI, pathology, surgery type, blood loss, morbidity, return to theatre, hospital stay, and readmission rate were collected and compared with a consecutive series over the preceding 6 months performed laparoscopically by the same team. A comparison of two consecutive series was made. The mean age was somewhat different, 55 years in the robotic versus 69 years in the laparoscopic group, but obesity was a feature of both groups with a mean of BMI 29.3 versus 28.06, respectively. This difference was not statistically significant (P = 0.54). Three subgroups of minimal access surgical procedures were performed: total hysterectomy and bilateral salpingooophorectomy (TH + BSO), total hysterectomy and bilateral salpingooophorectomy plus bilateral pelvic lymphadenectomy (TH + BSO + BPLND), and radical hysterectomy plus bilateral pelvic lymphadenectomy (RH + BPLND). The mean time taken to perform surgery for TH + BSO was longer in the robotic group, 151.2 min compared to 126.3 min in the laparoscopic group. TH + BSO + BPLND surgical time was similar to 178.3 min in robotic group and 176.5 min in laparoscopic group. RH + BPLND surgical time was similar, 263.6 min (robotic arm) and 264.0 min (laparoscopic arm). However, the numbers in this initial analysis were small especially in the last two subgroups and do not allow for statistical analysis. The rate of complications necessitating intervention

  11. Surgical bleeding in microgravity

    Science.gov (United States)

    Campbell, M. R.; Billica, R. D.; Johnston, S. L. 3rd

    1993-01-01

    A surgical procedure performed during space flight would occur in a unique microgravity environment. Several experiments performed during weightlessness in parabolic flight were reviewed to ascertain the behavior of surgical bleeding in microgravity. Simulations of bleeding using dyed fluid and citrated bovine blood, as well as actual arterial and venous bleeding in rabbits, were examined. The high surface tension property of blood promotes the formation of large fluid domes, which have a tendency to adhere to the wound. The use of sponges and suction will be adequate to prevent cabin atmosphere contamination with all bleeding, with the exception of temporary arterial droplet streams. The control of the bleeding with standard surgical techniques should not be difficult.

  12. Surgical management of presbyopia

    Directory of Open Access Journals (Sweden)

    Torricelli AA

    2012-09-01

    Full Text Available André AM Torricelli, Jackson B Junior, Marcony R Santhiago, Samir J BecharaDivision of Ophthalmology, University of São Paulo Medical School, São Paulo, BrazilAbstract: Presbyopia, the gradual loss of accommodation that becomes clinically significant during the fifth decade of life, is a physiologic inevitability. Different technologies are being pursued to achieve surgical correction of this disability; however, a number of limitations have prevented widespread acceptance of surgical presbyopia correction, such as optical and visual distortion, induced corneal ectasia, haze, anisometropy with monovision, regression of effect, decline in uncorrected distance vision, and the inherent risks with invasive techniques, limiting the development of an ideal solution. The correction of the presbyopia and the restoration of accommodation are considered the final frontier of refractive surgery. The purpose of this paper is to provide an update about current procedures available for presbyopia correction, their advantages, and disadvantages.Keywords: presbyopia, surgical correction, treatment

  13. Cephalomedullary fixation for femoral neck/intertrochanteric and ipsilateral shaft fractures: surgical tips and pitfalls

    Institute of Scientific and Technical Information of China (English)

    Kamal Bali; Nitesh Gahlot; Sameer Aggarwal; Vijay Goni

    2013-01-01

    Objective:Surgical management options for femoral shaft fracture and ipsilateral proximal femur fracture vary from single-implant to double-implant fixation.Cephalomedullary fixation in such fractures has relative advantages over other techniques especially because of less soft tissue dissection and immediate postoperative weight beating with accelerated rehabilitation.However,the surgery is technically demanding and there is a paucity of literature describing the surgical techniques for this fixation.The aim of the study was to describe the surgical technique of cephalomedullary fixation for femoral shaft fracture and ipsilateral proximal femur fracture.Methods:Sixteen cases (10 males and 6 females with a mean age of 41.8 years) ofipsilateral proximal femur and shaft fractures were treated by single-stage cephalomedullary fixation at tertiary level trauma center in northern India.The fractures were classified according to AO classification.An intraoperative record of duration of surgery as well as technical challenges unique to each fracture pattern was kept for all the patients.ResuRs:The most common proximal femoral pattern was AO B2.1 observed in 9 of our patients.The AO B2.3 fractures were seen in 4 patients while the AO A1.2 fractures in 3 patients.Four of the AO B2.1 and 2 of the AO B2.3 fractures required open reduction with Watson-Jones approach.The mean operative time was around 78 minutes,which tended to decrease as the surgical experience increased.There was only one case of malreduction,which required revision surgery.Conclusion:Combination of ipsilateral femoral shaft fracture and neck/intertrochanteric fracture is a difficult fracture pattern for trauma surgeons.Cephalomedullary nail is an excellent implant for such fractures but it requires careful insertion to avoid complications.Surgery is technically demanding with a definite learning curve.Nevertheless,a majority of these fractures can be surgically managed by singleimplant cephaiomedullary

  14. Usability Assessment of Two Different Control Modes for the Master Console of a Laparoscopic Surgical Robot

    Directory of Open Access Journals (Sweden)

    Xiaoli Zhang

    2012-01-01

    Full Text Available The objective of this study is to evaluate potential interface control modes for a compact four-degree-of-freedom (4-DOF surgical robot. The goal is to improve robot usability by incorporating a sophisticated haptics-capable interface. Two control modes were developed using a commercially available haptic joystick: (1 a virtually point-constrained interface providing an analog for constrained laparoscopic motion (3-DOF rotation and 1-DOF translation, and (2 an unconstrained Cartesian input interface mapping more directly to the surgical tool tip motions. Subjects (n = 5 successfully performed tissue identification and manipulation tasks in an animal model in point-constrained and unconstrained control modes, respectively, with speed roughly equal to that achieved in similar manual procedures, and without a steep learning curve. The robot control was evaluated through bench-top tests and a subsequent qualitative questionnaire (n = 15. The results suggest that the unconstrained control mode was preferred for both camera guidance and tool manipulations.

  15. A catalog of special plane curves

    CERN Document Server

    Lawrence, J Dennis

    2014-01-01

    Among the largest, finest collections available-illustrated not only once for each curve, but also for various values of any parameters present. Covers general properties of curves and types of derived curves. Curves illustrated by a CalComp digital incremental plotter. 12 illustrations.

  16. Surgical data science: the new knowledge domain

    Directory of Open Access Journals (Sweden)

    Vedula S. Swaroop

    2017-04-01

    assessments, automated virtual coaching, and robot-assisted active learning of surgical skill. However, the potential for transforming surgical care and training through SDS may only be realized through a cultural shift that not only institutionalizes technology to seamlessly capture data but also assimilates individuals with expertise in data science into clinical research teams. Furthermore, collaboration with industry partners from the inception of the discovery process promotes optimal design of data products as well as their efficient translation and commercialization. As surgery continues to evolve through advances in technology that enhance delivery of care, SDS represents a new knowledge domain to engineer surgical care of the future.

  17. Surgical data science: The new knowledge domain.

    Science.gov (United States)

    Vedula, S Swaroop; Hager, Gregory D

    2017-04-01

    -assisted active learning of surgical skill. However, the potential for transforming surgical care and training through SDS may only be realized through a cultural shift that not only institutionalizes technology to seamlessly capture data but also assimilates individuals with expertise in data science into clinical research teams. Furthermore, collaboration with industry partners from the inception of the discovery process promotes optimal design of data products as well as their efficient translation and commercialization. As surgery continues to evolve through advances in technology that enhance delivery of care, SDS represents a new knowledge domain to engineer surgical care of the future.

  18. Principal Curves on Riemannian Manifolds

    DEFF Research Database (Denmark)

    Hauberg, Søren

    2015-01-01

    Euclidean statistics are often generalized to Riemannian manifolds by replacing straight-line interpolations with geodesic ones. While these Riemannian models are familiar-looking, they are restricted by the inflexibility of geodesics, and they rely on constructions which are optimal only...... in Euclidean domains. We consider extensions of Principal Component Analysis (PCA) to Riemannian manifolds. Classic Riemannian approaches seek a geodesic curve passing through the mean that optimize a criteria of interest. The requirements that the solution both is geodesic and must pass through the mean tend...... from Hastie & Stuetzle to data residing on a complete Riemannian manifold. We show that for elliptical distributions in the tangent of spaces of constant curvature, the standard principal geodesic is a principal curve. The proposed model is simple to compute and avoids many of the pitfalls...

  19. Invariance for Single Curved Manifold

    KAUST Repository

    Castro, Pedro Machado Manhaes de

    2012-08-01

    Recently, it has been shown that, for Lambert illumination model, solely scenes composed by developable objects with a very particular albedo distribution produce an (2D) image with isolines that are (almost) invariant to light direction change. In this work, we provide and investigate a more general framework, and we show that, in general, the requirement for such in variances is quite strong, and is related to the differential geometry of the objects. More precisely, it is proved that single curved manifolds, i.e., manifolds such that at each point there is at most one principal curvature direction, produce invariant is surfaces for a certain relevant family of energy functions. In the three-dimensional case, the associated energy function corresponds to the classical Lambert illumination model with albedo. This result is also extended for finite-dimensional scenes composed by single curved objects. © 2012 IEEE.

  20. Optical conductivity of curved graphene.

    Science.gov (United States)

    Chaves, A J; Frederico, T; Oliveira, O; de Paula, W; Santos, M C

    2014-05-07

    We compute the optical conductivity for an out-of-plane deformation in graphene using an approach based on solutions of the Dirac equation in curved space. Different examples of periodic deformations along one direction translates into an enhancement of the optical conductivity peaks in the region of the far- and mid-infrared frequencies for periodicities ∼100 nm. The width and position of the peaks can be changed by dialling the parameters of the deformation profiles. The enhancement of the optical conductivity is due to intraband transitions and the translational invariance breaking in the geometrically deformed background. Furthermore, we derive an analytical solution of the Dirac equation in a curved space for a general deformation along one spatial direction. For this class of geometries, it is shown that curvature induces an extra phase in the electron wave function, which can also be explored to produce interference devices of the Aharonov-Bohm type.

  1. Supersymmetric Spacetimes from Curved Superspace

    CERN Document Server

    Kuzenko, Sergei M

    2015-01-01

    We review the superspace technique to determine supersymmetric spacetimes in the framework of off-shell formulations for supergravity in diverse dimensions using the case of 3D N=2 supergravity theories as an illustrative example. This geometric formalism has several advantages over other approaches advocated in the last four years. Firstly, the infinitesimal isometry transformations of a given curved superspace form, by construction, a finite-dimensional Lie superalgebra, with its odd part corresponding to the rigid supersymmetry transformations. Secondly, the generalised Killing spinor equation, which must be obeyed by the supersymmetry parameters, is a consequence of the more fundamental superfield Killing equation. Thirdly, general rigid supersymmetric theories on a curved spacetime are readily constructed in superspace by making use of the known off-shell supergravity-matter couplings and restricting them to the background chosen. It is the superspace techniques which make it possible to generate arbitra...

  2. Curved canals: Ancestral files revisited

    Directory of Open Access Journals (Sweden)

    Jain Nidhi

    2008-01-01

    Full Text Available The aim of this article is to provide an insight into different techniques of cleaning and shaping of curved root canals with hand instruments. Although a plethora of root canal instruments like ProFile, ProTaper, LightSpeed ® etc dominate the current scenario, the inexpensive conventional root canal hand files such as K-files and flexible files can be used to get optimum results when handled meticulously. Special emphasis has been put on the modifications in biomechanical canal preparation in a variety of curved canal cases. This article compiles a series of clinical cases of root canals with curvatures in the middle and apical third and with S-shaped curvatures that were successfully completed by employing only conventional root canal hand instruments.

  3. [Optimizing surgical hand disinfection].

    Science.gov (United States)

    Kampf, G; Kramer, A; Rotter, M; Widmer, A

    2006-08-01

    For more than 110 years hands of surgeons have been treated before a surgical procedure in order to reduce the bacterial density. The kind and duration of treatment, however, has changed significantly over time. Recent scientific evidence suggests a few changes with the aim to optimize both the efficacy and the dermal tolerance. Aim of this article is the presentation and discussion of new insights in surgical hand disinfection. A hand wash should be performed before the first disinfection of a day, ideally at least 10 min before the beginning of the disinfection as it has been shown that a 1 min hand wash significantly increases skin hydration for up to 10 min. The application time may be as short as 1.5 min depending on the type of hand rub. Hands and forearms should be kept wet with the hand rub for the recommended application time in any case. A specific rub-in procedure according to EN 12791 has been found to be suitable in order to avoid untreated skin areas. The alcohol-based hand rub should have a proven excellent dermal tolerance in order to ensure appropriate compliance. Considering these elements in clinical practice can have a significant impact to optimize the high quality of surgical hand disinfection for prevention of surgical site infections.

  4. A Study of Hyperelliptic Curves in Cryptography

    Directory of Open Access Journals (Sweden)

    Reza Alimoradi

    2016-08-01

    Full Text Available Elliptic curves are some specific type of curves known as hyper elliptic curves. Compared to the integer factorization problem(IFP based systems, using elliptic curve based cryptography will significantly decrease key size of the encryption. Therefore, application of this type of cryptography in systems that need high security and smaller key size has found great attention. Hyperelliptic curves help to make key length shorter. Many investigations are done with regard to improving computations, hardware and software implementation of these curves, their security and resistance against attacks. This paper studies and analyzes researches done about security and efficiency of hyperelliptic curves.

  5. Elastic Curves on the Sphere

    Science.gov (United States)

    1992-12-16

    12 = (K,, + )- (29) K 2 (see [3]). The parameter KM represents the amplitude of the periodic curva - ture function and sm denotes the value at which K...Additamentum De curvis elasticis. Methodus Inveniendi Lineas Curvas Maximi Minimive Proprietate Gaudentes, Ser. 1., Vol. 24, Lausanne 1744. 17 [10...Mathematical Theory of Elasticity. 4th. ed., Cambridge University Press, 1927. [12] G. Nielson. Bernstein/ Bezier Curves and Splines on Spheres based upon

  6. Accelerating Around an Unbanked Curve

    Science.gov (United States)

    Mungan, Carl E.

    2006-02-01

    The December 2004 issue of TPT presented a problem concerning how a car should accelerate around an unbanked curve of constant radius r starting from rest if it is to avoid skidding. Interestingly enough, two solutions were proffered by readers.2 The purpose of this note is to compare and contrast the two approaches. Further experimental investigation of various turning strategies using a remote-controlled car and overhead video analysis could make for an interesting student project.

  7. [da Vinci surgical system].

    Science.gov (United States)

    Watanabe, Gou; Ishikawa, Norihiro

    2014-07-01

    The da Vinci surgical system was developed by Intuitive Surgical Inc. in the United States as an endoscopic surgical device to assist remote control surgeries. In 1998, the Da Vinci system was first used for cardiothoracic procedures. Currently a combination of robot-assisted internal thoracic artery harvest together with coronary artery bypass grafting (CABG) through a mini-incision (ThoraCAB) or totally endoscopic procedures including anastomoses under robotic assistance (TECAB) are being conducted for the treatment of coronary artery diseases. With the recent advances in catheter interventions, hybrid procedures combining catheter intervention with ThoraCAB or TECAB are anticipated in the future.On the other hand, with the decrease in number of coronary artery bypass surgeries, the share of valvular surgeries is expected to increase in the future. Among them, mitral valvuloplasty for mitral regurgitation is anticipated to be conducted mainly by low-invasive procedures, represented by minimally invasive cardiac surgery( MICS) and robot-assisted surgery. Apart from the intrinsic good surgical view, robotic-assisted systems offer additional advantages of the availability of an amplified view and the easy to observe the mitral valve in the physiological position. Thus, robotic surgical surgeries that make complicated procedures easier are expected to accomplish further developments in the future. Furthermore, while the number of surgeries for atrial septal defects has decreased dramatically following the widespread use of Amplatzer septal occluder, robotic surgery may become a good indication for cases in which the Amplatzer device is not indicated. In Japan, clinical trial of the da Vinci robotic system for heart surgeries has been completed. Statutory approval of the da Vinci system for mitral regurgitation and atrial septal defects is anticipated in the next few years.

  8. Macdonald formula for curves with planar singularities

    CERN Document Server

    Maulik, Davesh

    2011-01-01

    We generalize Macdonald's formula for the cohomology of Hilbert schemes of points on a curve from smooth curves to curves with planar singularities: we relate the cohomology of the Hilbert schemes to the cohomology of the compactified Jacobian of the curve. The new formula is a consequence of a stronger identity between certain perverse sheaves defined by a family of curves satisfying mild conditions, whose proof makes an essential use of Ng\\^o's support theorem for compactified Jacobians.

  9. Method for estimating spin-spin interactions from magnetization curves

    Science.gov (United States)

    Tamura, Ryo; Hukushima, Koji

    2017-02-01

    We develop a method to estimate the spin-spin interactions in the Hamiltonian from the observed magnetization curve by machine learning based on Bayesian inference. In our method, plausible spin-spin interactions are determined by maximizing the posterior distribution, which is the conditional probability of the spin-spin interactions in the Hamiltonian for a given magnetization curve with observation noise. The conditional probability is obtained with the Markov chain Monte Carlo simulations combined with an exchange Monte Carlo method. The efficiency of our method is tested using synthetic magnetization curve data, and the results show that spin-spin interactions are estimated with a high accuracy. In particular, the relevant terms of the spin-spin interactions are successfully selected from the redundant interaction candidates by the l1 regularization in the prior distribution.

  10. Lessons learned over a decade of pediatric robotic ureteral reimplantation

    Science.gov (United States)

    Baek, Minki

    2017-01-01

    The da Vinci robotic system has improved surgeon dexterity, ergonomics, and visualization to allow for a minimally invasive option for complex reconstructive procedures in children. Over the past decade, robot-assisted laparoscopic ureteral reimplantation (RALUR) has become a viable minimally invasive surgical option for pediatric vesicoureteral reflux (VUR). However, higher-than-expected complication rates and suboptimal reflux resolution rates at some centers have also been reported. The heterogeneity of surgical outcomes may arise from the inherent and underestimated complexity of the RALUR procedure that may justify its reclassification as a complex reconstructive procedure and especially for robotic surgeons early in their learning curve. Currently, no consensus exists on the role of RALUR for the surgical management of VUR. High success rates and low major complication rates are the expected norm for the current gold standard surgical option of open ureteral reimplantation. Similar to how robot-assisted laparoscopic surgery has gradually replaced open surgery as the most utilized option for prostatectomy in prostate cancer patients, RALUR may become a higher utilized surgical option in children with VUR if the adoption of standardized surgical techniques that have been associated with optimal outcomes can be adopted during the second decade of RALUR. A future standard of RALUR for children with VUR whose parents seek a minimally invasive surgical option can arise if widespread achievement of high success rates and low major complication rates can be obtained, similar to the replacement of open surgery with robot-assisted laparoscopic radical prostectomy as the new strandard for men with prostate cancer. PMID:28097262

  11. Monograph on propagation of sound waves in curved ducts

    Science.gov (United States)

    Rostafinski, Wojciech

    1991-01-01

    After reviewing and evaluating the existing material on sound propagation in curved ducts without flow, it seems strange that, except for Lord Rayleigh in 1878, no book on acoustics has treated the case of wave motion in bends. This monograph reviews the available analytical and experimental material, nearly 30 papers published on this subject so far, and concisely summarizes what has been learned about the motion of sound in hard-wall and acoustically lined cylindrical bends.

  12. [Pancoast tumors ; modified surgical approaches and techniques].

    Science.gov (United States)

    Tsunezuka, Yoshio; Yachi, T; Waseda, R; Yamamoto, D

    2010-01-01

    The surgical treatment of Pancoast tumors is associated with difficulties related to its anatomical locations. Different surgical approaches have been reported but every approaches have some advantages and disadvantages. We report 2 Pancoast tumors cases with unique surgical approaches and our techniques. Case 1 : A 38-year-old man complained of face edema. The chest computed tomography (CT) revealed an right anterior apical tumor with direct invasion of the 1st and 2nd rib. Preoperative chemotherapy with 2 courses of carboplatin [area under the blood concentration-time curve (AUC) 6, day 1] and paclitaxel (80 mg/m2, day1, 8, 15) and concurrent extracorporeal radiation (70 Gy) was used to treat the adenocarcinoma. The skin incision was performed according to Masaoka's anterior approach, and a proximal median sternotomy communicated with an incision in the 4th intercostal space. The clavicula was freed by the L-shaped incision on the manubrium and the 1st cartilage section according to Grunenwald method to retract the section. Case 2 : A 65-year-old man complained back pain. The chest CT revealed an right superior sulcus tumor, displaced bronchus (B1+B3 tracheal bronchus, B2) and pulmonary arteries anomalies. Combined Shaw-Paulson incision and 4 intercostal lateral thoracotomy was performed to right upper lobectomy and systematic lymph nodes dissection.

  13. The association of patient characteristics and spinal curve parameters with Lenke classification types.

    Science.gov (United States)

    Sponseller, Paul D; Flynn, John M; Newton, Peter O; Marks, Michelle C; Bastrom, Tracey P; Petcharaporn, Maty; McElroy, Mark J; Lonner, Baron S; Betz, Randal R

    2012-06-01

    Retrospective review. To determine the association of patient characteristics and spinal curve parameters with Lenke curve types. The Lenke curve classification may be used for surgical planning and clinical research. We retrospectively reviewed the records of 1912 patients with adolescent idiopathic scoliosis who underwent initial surgery at 21 years of age or younger; collected data on patient's age, patient's sex, primary curve magnitude (Society (SRS) outcomes questionnaire (SRS-22) score; and compared that data by Lenke curve type. Analysis of variance and χ tests were used as appropriate (significance level, P ≤ 0.005). RESULTS.: Lenke types vary by sex: male patients had more major thoracic (types 1-4) than major thoracolumbar/lumbar (types 5 and 6) curves, fewer lumbar C-modifiers (32% vs. 44%), and less apical lumbar translation (1.1 vs. 1.7 cm). Lenke types vary by frequency: the most common type was 1 (50%); the least common, 4 (4%). Lenke types vary by magnitude: type 4 had the greatest percentage of large curves (52% of curves .75°), most smaller curves were types 1 and 5, and type 4 had the largest mean magnitude (78° ± 17°). Lenke types vary by patient age: type 5 curves occurred in the oldest patients (average age at surgery: 15.4 ± 2.2 vs. 14.3 ± 14.6 years for all others) despite having the lowest mean magnitude (P = 0.001); curve size was negatively correlated with age at surgery (r = -0.16, P = 0.001). Lenke types vary by patient self-image: patients with type 4 curves had lower preoperative SRS outcome scores for self-image than did patients with type 1 curves (P = 0.005). Lenke types vary by sex, frequency magnitude, patient age, and patient self-image, which should be considered in designing studies.

  14. TACTIC IN SURGICAL TREATMENT OF THORACIC IDIOPATHIC SCOLIOSIS IN CHILDREN

    Directory of Open Access Journals (Sweden)

    S. V. Vissarionov

    2010-01-01

    Full Text Available The results of surgical treatment of 263 patients with thoracic scoliosis from 13 to 18 years old with deformity 50-152° (Cobb are presented. It was used three tactical variants with dorsal instrumentation Cotrel-Dubousset (CDI. Operation correction in idiopathic thoracic scoliosis varies within in limits from 46,2 to 95%. Lost of correction in 10 years follow up period was 5,10-10,15%. Authors concluded that tactic of surgical treatment of idiopathic thoracic scoliosis should be individual and depends on patient's age, growth potential, and degree of deformation and mobility of the curve.

  15. Vitiligo- A surgical approach

    Directory of Open Access Journals (Sweden)

    Deepti Ghia

    2012-01-01

    Full Text Available Aims and objective- To describe the spectrum of surgical modalities for stable vitiligo patients Methods- Patients having stable vitiligo since past 2 years with no improvement with medical line of treatment were enrolled for surgery after informed consent. Depending upon the size and location of vitiligo patch different modalities were performed. Suction blister, mini-punch grafting, split thickness skin grafting, trypsinised melanocyte-keratinocyte transfer and non-trypsinised melanocyte- keratinocyte transfer (Jodhpur technique and follicular grafting technique have been described photographically which have been performed at a tertiary care hospital. Conclusion- Vitiligo is often difficult to treat, stable patches resistant to medical line of management do respond to surgical treatment; however it is very important to choose the modality of surgery according location of the patch, size of the lesion and available resources.

  16. Spacecraft surgical scrub system

    Science.gov (United States)

    Abbate, M.

    1980-01-01

    Ease of handling and control in zero gravity and minimizing the quantity of water required were prime considerations. The program tasks include the selection of biocidal agent from among the variety used for surgical scrub, formulation of a dispensing system, test, and delivery of flight dispensers. The choice of an iodophore was based on effectiveness on single applications, general familiarity among surgeons, and previous qualification for space use. The delivery system was a choice between the squeeze foamer system and impregnated polyurethane foam pads. The impregnated foam pad was recommended because it is a simpler system since the squeeze foamer requires some applicator to effectively clean the skin surfaces, whereas the form pad is the applicator and agent combined. Testing demonstrated that both systems are effective for use as surgical scrubs.

  17. Predictors of curve flexibility in adolescent idiopathic scoliosis: a retrospective study of 100 patients.

    Science.gov (United States)

    Ameri, Ebrahim; Behtash, Hamid; Mobini, Bahram; Daraie, Ariasb

    2015-01-01

    Curve flexibility in adolescent idiopathic scoliosis (AIS) was one of the major concerns of spinal surgeons since the evolution of surgical correction techniques. In this respect, many tried to identify which criteria denote more rigid curve. In the present study, we aimed toward determining important factors influencing AIS curve flexibility on supine bending films. We assessed radiographs of 100 patients with AIS for direction of curves, number of involved vertebrae, apical vertebral translation and rotation, magnitude of main thoracic curve and T5-T12 kyphosis. Statistical analysis performed via stepwise linear regression model with these variables plus age and sex against flexibility index. According to regression analysis, there was a clear relationship between flexibility indexes (FI) and magnitude of main thoracic curve at all (P50%) against rigid curves, apical vertebral rotation was a major determinant of curve flexibility also (P<0.001). Adolescent idiopathic scoliosis curves with larger Cobb's angle and apical vertebral rotation show less flexibility on supine bending films.

  18. Predictors of curve flexibility in adolescent idiopathic scoliosis: a retrospective study of 100 patients.

    Directory of Open Access Journals (Sweden)

    Ebrahim Ameri

    2015-03-01

    Full Text Available Curve flexibility in adolescent idiopathic scoliosis (AIS was one of the major concerns of spinal surgeons since the evolution of surgical correction techniques. In this respect, many tried to identify which criteria denote more rigid curve. In the present study, we aimed toward determining important factors influencing AIS curve flexibility on supine bending films. We assessed radiographs of 100 patients with AIS for direction of curves, number of involved vertebrae, apical vertebral translation and rotation, magnitude of main thoracic curve and T5-T12 kyphosis. Statistical analysis performed via stepwise linear regression model with these variables plus age and sex against flexibility index. According to regression analysis, there was a clear relationship between flexibility indexes (FI and magnitude of main thoracic curve at all (P50% against rigid curves, apical vertebral rotation was a major determinant of curve flexibility also (P<0.001. Adolescent idiopathic scoliosis curves with larger Cobb's angle and apical vertebral rotation show less flexibility on supine bending films.

  19. LINS Curve in Romanian Economy

    Directory of Open Access Journals (Sweden)

    Emilian Dobrescu

    2016-02-01

    Full Text Available The paper presents theoretical considerations and empirical evidence to test the validity of the Laffer in Narrower Sense (LINS curve as a parabola with a maximum. Attention is focused on the so-called legal-effective tax gap (letg. The econometric application is based on statistical data (1990-2013 for Romania as an emerging European economy. Three cointegrating regressions (fully modified least squares, canonical cointegrating regression and dynamic least squares and three algorithms, which are based on instrumental variables (two-stage least squares, generalized method of moments, and limited information maximum likelihood, are involved.

  20. Principal -bundles on Nodal Curves

    Indian Academy of Sciences (India)

    Usha N Bhosle

    2001-08-01

    Let be a connected semisimple affine algebraic group defined over . We study the relation between stable, semistable -bundles on a nodal curve and representations of the fundamental group of . This study is done by extending the notion of (generalized) parabolic vector bundles to principal -bundles on the desingularization of and using the correspondence between them and principal -bundles on . We give an isomorphism of the stack of generalized parabolic bundles on with a quotient stack associated to loop groups. We show that if is simple and simply connected then the Picard group of the stack of principal -bundles on is isomorphic to ⊕ , being the number of components of .