416 research outputs found

    Constructions of diagonal quartic and sextic surfaces with infinitely many rational points

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    In this note we construct several infinite families of diagonal quartic surfaces \begin{equation*} ax^4+by^4+cz^4+dw^4=0, \end{equation*} where a,b,c,dZ{0}a,b,c,d\in\Z\setminus\{0\} with infinitely many rational points and satisfying the condition abcdabcd\neq \square. In particular, we present an infinite family of diagonal quartic surfaces defined over \Q with Picard number equal to one and possessing infinitely many rational points. Further, we present some sextic surfaces of type ax6+by6+cz6+dwi=0ax^6+by^6+cz^6+dw^i=0, i=2i=2, 33, or 66, with infinitely many rational points.Comment: revised version will appear in International Journal of Number Theor

    CIDI-Lung-Seg: A Single-Click Annotation Tool for Automatic Delineation of Lungs from CT Scans

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    Accurate and fast extraction of lung volumes from computed tomography (CT) scans remains in a great demand in the clinical environment because the available methods fail to provide a generic solution due to wide anatomical variations of lungs and existence of pathologies. Manual annotation, current gold standard, is time consuming and often subject to human bias. On the other hand, current state-of-the-art fully automated lung segmentation methods fail to make their way into the clinical practice due to their inability to efficiently incorporate human input for handling misclassifications and praxis. This paper presents a lung annotation tool for CT images that is interactive, efficient, and robust. The proposed annotation tool produces an "as accurate as possible" initial annotation based on the fuzzy-connectedness image segmentation, followed by efficient manual fixation of the initial extraction if deemed necessary by the practitioner. To provide maximum flexibility to the users, our annotation tool is supported in three major operating systems (Windows, Linux, and the Mac OS X). The quantitative results comparing our free software with commercially available lung segmentation tools show higher degree of consistency and precision of our software with a considerable potential to enhance the performance of routine clinical tasks.Comment: 4 pages, 6 figures; to appear in the proceedings of 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC 2014

    Low-pressure pneumoperitoneum with deep neuromuscular blockade in metabolic surgery to reduce postoperative pain:a randomized pilot trial

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    Background For metabolic laparoscopic surgery, higher pressures up to 20 mmHg are often used to create a surgical field of sufficient quality. This randomized pilot study aimed to determine the feasibility, safety and tolerability of low intraabdominal pressure (IAP) and deep neuromuscular blockade (NMB) to reduce postoperative pain. Methods In a teaching hospital in the Netherlands, 62 patients eligible for a laparoscopic Roux-en-Y gastric bypass (LRYGB) were randomized into one of four groups in a 2 x 2 factorial design: deep/moderate NMB and standard (20 mmHg)/low IAP (12 mmHg). Patient and surgical team were blinded. Primary outcome measure was the surgical field quality, scored on the Leiden-Surgical Rating Scale (L-SRS). Secondary outcome measures were (serious) adverse events, duration of surgery and postoperative pain. Results 62 patients were included. L-SRS was good or perfect in all patients that were operated under standard IAP with deep or moderate NMB. In 40% of patients with low IAP and deep NMB, an increase in IAP was needed to improve surgical overview. In patients with low IAP and moderate NMB, IAP was increased to improve surgical overview in 40%, and in 75% of these cases a deep NMB was requested to further improve the surgical overview. Median duration of surgery was 38 min (IQR34-40 min) in the group with standard IAP and moderate NMB and 52 min (IQR46-55 min) in the group with low IAP and deep NMB. Conclusions The combination of moderate NMB and low IAP can create insufficient surgical overview. Larger trials are needed to corroborate the findings of this study. Trial registration: Dutch Trial Register: Trial NL7050, registered 28 May 2018.

    The Influence of Surgical Experience on Postoperative Recovery in Fast-Track Bariatric Surgery

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    Introduction: Short duration of surgery is an important aspect in fast-track protocols. Peroperative training of surgical residents could influence the duration of surgery, possibly affecting patient outcome. This study evaluates the influence of the operator’s level of experience on patient outcome in fast-track bariatric surgery. Methods: Data was analyzed of all patients who underwent a primary laparoscopic Roux-en-Y gastric bypass (LRYGB) or laparoscopic sleeve gastrectomy (LSG) between January 2004 and July 2018. Residents were trained according to a stepwise training program. For each operator, learning curves of both procedures were created by dividing the procedures in time-subsequent groups (TSGs). Data was also analyzed by comparing “beginners” with “experienced operators,” with a cut-off point at 100 procedures. Primary outcome measure was duration of surgery. Secondary outcome measures were length of hospital stay (LOS), complications, and readmission rate within 30 days postoperatively. Results: There were 4901 primary procedures (53.1% LSG) performed by seven surgeons or surgical residents. We found no difference between beginning and experienced operators in complications or readmissions rates. The experience of the operator did not influence LOS (p = 0.201). Comparing each new operator with previous operator(s), the starting point in terms of duration of surgery was shorter, and thcorresponding author at Franciscus Gasthuis & Vlietland Rotterda

    Trust in Cash Assistance Programming: Addressing Mega Trend Changes through Disaster Management and Impact Assessment

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    NWO016.Veni.195.342Exploring the Frontiers of International La

    Quality of Life 1 Year After Laparoscopic Sleeve Gastrectomy Versus Laparoscopic Roux-en-Y Gastric Bypass: a Randomized Controlled Trial Focusing on Gastroesophageal Reflux Disease

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    Introduction: Bariatric surgery is the only treatment option that achieves sustained weight loss in obese patients and that also has positive effects on obesity-related comorbidities. Laparoscopic sleeve gastrectomy (LSG) seems to achieve equal weight loss as laparoscopic Roux-en-Y gastric bypass (LRYGB), but there is still much debate about the quality of life (QOL) after LSG, mainly concerning the association with gastroesophageal reflux. Our hypothesis is that QOL after LSG is comparable with QOL after LRYGB. Materials and Methods: Between February 2013 and February 2014, 150 patients were randomized to undergo either LSG or LRYGB in our clinic. Differences in QOL were compared between groups by using multiple QOL questionnaires at follow-up moments preoperatively and 2 and 12 months after surgery. Results: After 12 months of follow-up, 128 patients had returned the questionnaires. Most QOL questionnaires showed significant improvement in scores between the preoperative moment and after 12 months of follow-up. The Gastroesophageal Reflux Disease Questionnaire (GerdQ) score deteriorated in the LSG group after 2 months, but recovered again after 12 months. After 2 months of follow-up, the mean GerdQ score was 6.95 ± 2.14 in the LSG group versus 5.50 ± 1.49 in the LRYGB group (p < 0.001). After 1 year, the mean GerdQ score was 6.63 ± 2.26 in the LSG group and 5.60 ± 1.07 in the LRYGB group (p = 0.001). Conclusion: This randomized controlled trial shows that patients who underwent LSG have significantly higher GerdQ scores at both 2 and 12 months postoperatively than patients who underwent LRYGB, whereas overall QOL did not differ significantly
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