Split Function Research Articles

Spectrum of Disorders Diagnosed on 99mTc-MAG3 Radioisotope Renography: A Report of 260 Saudi Arabian Patients

Background: Diuretic renography using 99mTc-mercaptoacetyltriglycine (99mTc-MAG3) is a relatively non-invasive technique and has been increasingly used as a reliable technique for the evaluation of kidney function in a wide range of kidney disorders. Methods: In this retrospective study, we retrieved the medical records of patients referred to the Radiology Department of Radiology, King Abdulaziz Specialist Hospital, Taif, Saudi Arabia, with suspected kidney disease and underwent 99mTc-MAG3 diuretic renography during January 2020 to November 2021. Results: The medical records of 260 patients were retrieved. Most of the patients had either suspected obstructive (n = 80; 30.7 %) or non-obstructive hydronephrosis (n = 60; 23.1 %). The left kidney was affected in more than half of the patients (n = 155; 59.6 %). In terms of split kidney functions, the right kidney had a median function of 50.9 (38.5–75.5); overall, 39 patients (69.6%) had good right kidney function. The left kidney had a median function of 49.4 (24.5–61.5); overall, 33 patients (58.9%) had good left kidney function. Conclusion: Radioisotope renography is useful for assessing kidney functions in real-life settings. The present study’s results indicate that radioisotope renography using 99mTc-MAG3 is helpful in the visual interpretation of kidney failure, obstructive uropathy and kidney stenosis.

Numerically non-special varieties

Campana introduced the class of special varieties as the varieties admitting no Bogomolov sheaves, i.e. rank-one coherent subsheaves of maximal Kodaira dimension in some exterior power of the cotangent bundle. Campana raised the question of whether one can replace the Kodaira dimension by the numerical dimension in this characterization. We answer partially this question showing that a projective manifold admitting a rank-one coherent subsheaf of the cotangent bundle with numerical dimension one is not special. We also establish the analytic characterization with the non-existence of Zariski dense entire curve and the arithmetic version with non-potential density in the (split) function field setting. Finally, we conclude with a few comments for higher codimensional foliations which may provide some evidence towards a generalization of the aforementioned results.

Evaluation of Functional Operability Prior to Lung Surgery

Cardiac and pulmonary physiologic assessment is necessary for risk stratification before any lung resection. It may uncover hidden health issues, which can be addressed first to make patients fit for surgery. It allows for the surgeon to estimate the patient's risk for major complications and at the same time for the patient to understand the procedural risks and give informed consent or even reject surgery. Recommended work-up for both to cardiac risk evaluation and preoperative pulmonary function test algorithms are based on guidelines formulated by the ERS/ESTS and ACCP 1 3 4.Basic pulmonary function tests consist of spirometry, blood gas analysis and measurement of diffusion capacity (DLCO); followed by cardiopulmonary exercise testing (CPET) which estimates or measures the patient's oxygen consumption, and split function tests such as perfusion scintigraphy. Clinical assessment of both the patient's overall status and pulmonary function allows for an adequate assessment of overall operative risk. Pulmonary function tests are affected by multiple variables and as such prone to error. It is advisable to always question the validity of every work-up and to repeat any test if necessary.

Celestial operator products from the worldsheet

We compute the operator product expansions of gluons and gravitons in celestial CFT from the worldsheet OPE of vertex operators of four-dimensional ambitwistor string theories. Remarkably, the worldsheet OPE localizes on the short-distance singularity between vertex operator insertions which in turn coincides with the OPE limit of operator insertions on the celestial sphere. The worldsheet CFT dynamically produces known celestial OPE coefficients — as well as infinite towers of SL(2, ℝ) descendant contributions to the celestial OPE — without any truncations or approximations. We obtain these results for all helicities and incoming/outgoing configurations. Furthermore, the worldsheet OPE encodes the infinite-dimensional symmetry algebras associated with the conformally soft sectors of gauge theory and gravity. We provide explicit operator realizations of the currents generating these symmetries on ambitwistor space in terms of vertex operators for soft gluons and gravitons, also computing their actions on hard particles of all helicities. Lastly, we show that the worldsheet OPE for momentum eigenstates produces the collinear splitting functions of gluons and gravitons.

Preservation of Split Renal Function After Laparoscopic and Robot-assisted Partial Nephrectomy.

To analyze the effects of laparoscopic partial nephrectomy (LPN) and robot-assisted partial nephrectomy (RAPN) for the treatment of renal cell carcinoma (RCC) on subsequent split renal function using renal scintigraphy. We retrospectively analyzed data from 174 patients who underwent LPN or RAPN by a single surgeon, and assessed their total and split renal function before and 6 months after each procedure. Split renal function was analyzed using 99mTc-2,3 dimercaptosuccinic acid renal imaging and calculated as the total estimated glomerular filtration rate (eGFR) × uptake ratio on the surgical side/uptake ratio on the contralateral side. LPN or RAPN were performed in 51 (29.3%) and 123 (70.7%) participants, respectively. Their median eGFRs before and after surgery were 32.76 and 27.74 ml/min/1.73 m2, respectively, and 70 of them (40.2%) showed a preservation of split eGFR of >90%, which was used to define a successful procedure. Participants who underwent a successful procedure had significantly lower RENAL nephrometry scoring system (RNS) scores and fewer of them had external tumors. Successful procedures were associated with shorter warm ischemia time, were more likely to be RAPN, and less likely to involve parenchymal suturing. Multivariate analysis showed that a low RNS score and parenchymal suturing were significant independent predictors of split renal function following partial nephrectomy (PN). Preoperative RNS score and the use of parenchymal suturing are significantly associated with a preservation of split renal function of >90% in patients who undergo PN for the treatment of RCC.

Renormalization of gluonic leading-twist operators in covariant gauges

We provide the all-loop structure of gauge-variant operators required for the renormalisation of Green’s functions with insertions of twist-two operators in Yang-Mills theory. Using this structure we work out an explicit basis valid up to 4-loop order for an arbitrary compact simple gauge group. To achieve this we employ a generalised gauge symmetry, originally proposed by Dixon and Taylor, which arises after adding to the Yang-Mills Lagrangian also operators proportional to its equation of motion. Promoting this symmetry to a generalised BRST symmetry allows to generate the ghost operator from a single exact operator in the BRST-generalised sense. We show that our construction complies with the theorems by Joglekar and Lee. We further establish the existence of a generalised anti-BRST symmetry which we employ to derive non-trivial relations among the anomalous dimension matrices of ghost and equation-of-motion operators. For the purpose of demonstration we employ the formalism to compute the N = 2, 4 Mellin moments of the gluonic splitting function up to 4 loops and its N = 6 Mellin moment up to 3 loops, where we also take advantage of additional simplifications of the background field formalism.

Percutaneous nephrostomy in Ureteropelvic junction obstruction with poorly functioning kidney: Is it still pertinent in adults?

To determine the pertinence of percutaneous nephrostomy drainage in adult patients of primary ureteropelvic junction obstruction with poorly functioning kidneys (<20% split renal function). Clinical records of all patients with primary ureteropelvic junction obstruction with poorly functioning kidneys who underwent percutaneous nephrostomy drainage in our institute between February 2015 and January 2020 were retrospectively reviewed. The patients were divided into 4 groups according to their split renal function obtained from the Tc-99m ethylenedicysteine diuretic renogram. Group I consisted of all patients having split renal function ≤5%, group II with split renal function 6-10%, groupIII with split renal function 11-15%, and finally group IV with split renal function 16-20%. Those patients inwhom split renal function was improved by >10% and had daily percutaneous nephrostomy output >400 mL, underwent pyeloplasty and the rest underwent nephrectomy. Seventy-two patients were studied, out of which 5 were in group I, 20 in groups II and III each, and27 in group IV. The mean age of presentation was 34.4 ± 14 years. The split renal function improvement of>10% was seen in 55 patients (76.4%) after percutaneous nephrostomy drainage (P < .05). Pyeloplasty wasdone in 40 patients (55.6%) and nephrectomy was done in 32 patients (44.4%). In conclusion, we recommend the use of a Tc-99m ethylenedicysteine scan for estimation of split renal function during the initial presentation in every patient followed by reconstructive surgery if split renal function is above 15% and nephrectomy if it is below 5%. The trial of percutaneous nephrostomy is pertinent if split renal function is between 6% and 15%.

Attaining competency and proficiency in open pyeloplasty: a learning curve configuration using cumulative sum analysis.

The learning curves for minimally invasive pyeloplasty techniques have been described in the past. However, the learning curve in achieving competency in open pyeloplasty has not been described. Hence, we aim to evaluate a single surgeon series of open pyeloplasty technique using the cumulative sum (CUSUM) methodology. We retrospectively reviewed all open pyeloplasties performed by a single surgeon (AJL) between January 2008 and March 2020. Collected variables included: sex, age at surgery, operative time, hospital stay, pre-operative ultrasound, pre-operative nuclear scans, pre-operative anteroposterior diameter, associated anomalies, laterality (left or right), type of stent, pre-operative split renal function, and duration of follow-up. A CUSUM analysis was used: the highest peak, plateau and downward trends for complications (defined as Clavien-Dindo classification ≥ 3b) were identified on the plot and set as the transition points between five phases (learning, competency, proficiency, case-mix, and mastery). Based on the CUSUM analysis, the index surgeon reached the competency phase after performing their 13th open pyeloplasty and became proficient after the 70th case. In the case-mix phase (104th-126th cases), where the surgeon may be performing more complex cases while increasing trainee involvement, there was a slight increase in complication rates. After the 126th case, the surgeon entered the mastery phase, where there was consistent decreasing trend in complications. Surgeons performing open pyeloplasty in children following completion of their surgical training will continue to learn through their early cases until achieving competency. Technical competency may be reached after the 13th case. In this report, we looked at the number of cases to become proficient in open pyeloplasty procedure in children. A surgeon may achieve technical proficiency in the procedure after their 13th case.

Helicity-dependent distribution of strange quarks in the proton from nonlocal chiral effective theory

The helicity-dependent strange quark distribution in the proton, $\Delta s$, is calculated in a nonlocal chiral SU(3) effective field theory. The hadronic proton to meson plus octet or decuplet baryon splitting functions are derived at the one-loop level, with loop integrals rendered finite by correlation functions introduced in the nonlocal Lagrangian. Within the convolution framework, the proton strange helicity distribution is obtained using spin-flavor symmetry to constrain the input valence quark distributions in the hadronic intermediate states. The polarized strange quark distribution is found to be quite small, with the lowest moment of $\Delta s$ negative, but consistent with recent global QCD analyses.

Design of a Multi-Functional Integrated Optical Switch Based on Phase Change Materials

An optical switch based on silicon-on-insulator (SOI) technology is proposed that works in the C-band and switches by amorphous (Am) to crystalline (Cr) and Cr-to-Am phase transitions. The optical switch integrates the functions of polarization beam splitting and mode conversion, and consists of two asymmetric directional couplers (ADCs). The TM0 mode is converted to the TM1 mode through an asymmetric coupler to achieve the polarization splitting of the TM0 mode and TE0 mode. The output of the TE0 mode is then controlled by Ge2Sb2Se4Te1 (GSST). When the TE0 mode is input and the wavelength is 1550 nm, the insertion loss (IL) is lower than 0.62 dB and the crosstalk (CT) is lower than −9.88 dB for a directional coupler loaded with GSST that realizes the optical switch function in both amorphous and crystalline GSST. The extinction ratio (ER) of the two waveguides of the directional coupler is lower than −11.40 dB, simultaneously. When the TM0 mode is input and the wavelength is 1550 nm, the IL is lower than 0.62 dB for a directional coupler loaded without GSST.

PD56-01 IMPROVED PREDICTION OF RENAL FUNCTION AFTER RADICAL NEPHRECTOMY

You have accessJournal of UrologyCME1 May 2022PD56-01 IMPROVED PREDICTION OF RENAL FUNCTION AFTER RADICAL NEPHRECTOMY Nityam Rathi, Yosuke Yasuda, Diego Aguilar Palacios, Yunlin Ye, Jianbo Li, Christopher Weight, Mohammed Eltemamy, Robert Abouassaly, and Steven Campbell Nityam RathiNityam Rathi More articles by this author , Yosuke YasudaYosuke Yasuda More articles by this author , Diego Aguilar PalaciosDiego Aguilar Palacios More articles by this author , Yunlin YeYunlin Ye More articles by this author , Jianbo LiJianbo Li More articles by this author , Christopher WeightChristopher Weight More articles by this author , Mohammed EltemamyMohammed Eltemamy More articles by this author , Robert AbouassalyRobert Abouassaly More articles by this author , and Steven CampbellSteven Campbell More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002636.01AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Radical nephrectomy (RN) is an important consideration for the surgical management of localized renal cell carcinoma (RCC), particularly in cases of increased oncologic potential. However, reduced renal function after RN is a concern. Preoperative global glomerular filtration rate (GFR) and split renal function (SRF) in the contralateral kidney have been shown to be strong predictors of new baseline GFR (NBGFR) post-RN. Recently, software has been developed to perform parenchymal volume analysis (PVA) on preoperative imaging to determine SRF (FUJIFILM Medical Systems). We compare the abilities of two SRF-based models, using either nuclear renal scan (NRS) or PVA to determine SRF, to predict NBGFR after RN. These SRF-based models were also compared with subjective prediction of NBGFR by an experienced urologic oncologist, because some believe that an expert can predict such outcomes accurately and that predictive models may not be needed in this domain. METHODS: All 187 RCC patients who underwent RN (2006-16) with preoperative CT/MRI, NRS, and preop/postoperative GFR estimations were analyzed. NBGFR was defined as GFR 3-12 months after RN. For the two SRF-based approaches, SRF was derived from either NRS or semi-automated PVA software, and renal functional compensation was estimated at 25% based on previous studies. Thus, the formula (Global GFRPre-RN × SRFcontralateral) x 1.25 was used to predict NBGFR. For the “Subjective Approach”, a blinded, independent urologic oncologist provided predictions of NBGFR based on preoperative CT/MRI, baseline global GFR, tumor features, and patient age/comorbidities. Predictive accuracies were assessed by correlation coefficients (r). RESULTS: The r for the Subjective Assessment, NRS/SRF-based, and PVA/SRF-based approaches were 0.72, 0.72, and 0.85, respectively (Fig. 1). An SRF-based model using PVA to determine SRF performed better than NRS/SRF-based and Subjective approaches (both p < 0.05). CONCLUSIONS: Software-based PVA more accurately predicts NBGFR after RN than NRS and Subjective Assessment. The readily-available, inexpensive PVA software provides a precise and accurate estimation of SRF from routine preoperative CT/MRI. Clinically, this practical and innovative approach can contribute to the assessment of the merits and risks of RN versus partial nephrectomy in complex RCC cases. Source of Funding: None © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e953 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Nityam Rathi More articles by this author Yosuke Yasuda More articles by this author Diego Aguilar Palacios More articles by this author Yunlin Ye More articles by this author Jianbo Li More articles by this author Christopher Weight More articles by this author Mohammed Eltemamy More articles by this author Robert Abouassaly More articles by this author Steven Campbell More articles by this author Expand All Advertisement PDF DownloadLoading ...

V10-03 3D VIRTUAL MODELS APPLICATION FOR AN ANATOMIC-FUNCTIONAL APPROACH TO HIGHLY COMPLEX RENAL TUMORS WITH IMPERATIVE INDICATIONS TO NEPHRON SPARING SURGERY

You have accessJournal of UrologyCME1 May 2022V10-03 3D VIRTUAL MODELS APPLICATION FOR AN ANATOMIC-FUNCTIONAL APPROACH TO HIGHLY COMPLEX RENAL TUMORS WITH IMPERATIVE INDICATIONS TO NEPHRON SPARING SURGERY Daniele Amparore, Angela Pecoraro, Federico Piramide, Paolo Verri, Enrico Checcucci, Sabrina De Cillis, Alberto Piana, Matteo Manfredi, Cristian Fiori, and Francesco Porpiglia Daniele AmparoreDaniele Amparore More articles by this author , Angela PecoraroAngela Pecoraro More articles by this author , Federico PiramideFederico Piramide More articles by this author , Paolo VerriPaolo Verri More articles by this author , Enrico CheccucciEnrico Checcucci More articles by this author , Sabrina De CillisSabrina De Cillis More articles by this author , Alberto PianaAlberto Piana More articles by this author , Matteo ManfrediMatteo Manfredi More articles by this author , Cristian FioriCristian Fiori More articles by this author , and Francesco PorpigliaFrancesco Porpiglia More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002623.03AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: For some renal tumors, the indication to nephron sparing surgery (NSS) becomes imperative, such as chronic kidney disease (CKD) and bilateral tumours. For these patients three-dimensional virtual models (3DVMs) assistance could allow to reshape the surgical strategy, considering the anatomy of the organ in a perspective of postoperative real organ functioning instead of focusing the surgery on the tumor excision alone. METHODS: Three patients with high complexity renal masses, with abnormal anatomy and imperative indication to NSS were selected. All patients performed contrast-enhanced CT from which a 3DVM was obtained. Using such technological tools, it was possible to set the surgical strategy considering the anatomical kidney details, leading the surgeon to plan the sacrifice of the upper portion of the whole organ in light of its irrelevant contribution to the postoperative global renal function even if spared. RESULTS: Two out of three patients harbored bilateral renal tumors. The third patient presented a renal mass in the left kidney and a contralateral renal hypoplasia (right split renal function of 25%). All of them demonstrated similar anatomical and tumoral features, with a potential independent vascularization and drainage for the lower pole. In one of them the upper pole of the kidney was spared, exiting in an hydrocalyx functionally excluded, while in the other two cases it was removed together with the lesion. The spared portion of the kidney-maintained vascularization, as demonstrated by intraoperative ultrasound and indocyanine green injection. CONCLUSIONS: 3DVMs, especially in case of complex renal masses with imperative indication to NSS, allow to plan the surgical strategy on the basis of the anatomical characteristics of the organ in which the tumor grows, focusing the attention on the effective functional gain of the surgery, even considering sacrificing portions of the organ technically preservable but functionally not useful. Source of Funding: None © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e849 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Daniele Amparore More articles by this author Angela Pecoraro More articles by this author Federico Piramide More articles by this author Paolo Verri More articles by this author Enrico Checcucci More articles by this author Sabrina De Cillis More articles by this author Alberto Piana More articles by this author Matteo Manfredi More articles by this author Cristian Fiori More articles by this author Francesco Porpiglia More articles by this author Expand All Advertisement PDF DownloadLoading ...

MP17-07 IMPACT OF DELAY IN SURGICAL INTERVENTION ON FUNCTIONAL OUTCOME IN CHILDREN WITH UNILATERAL URETERO-PELVIC JUNCTION OBSTRUCTION

You have accessJournal of UrologyCME1 May 2022MP17-07 IMPACT OF DELAY IN SURGICAL INTERVENTION ON FUNCTIONAL OUTCOME IN CHILDREN WITH UNILATERAL URETERO-PELVIC JUNCTION OBSTRUCTION Mohamed Soltan, Ahmed Abdelhalim, Ahmed Elkashef, Mohamed Edwan, Ahmed Atwa, Mohamed Abou-El_Ghar, Tamer Helmy, Ashraf Tarek, Mohamed Dawaba, and Ahmed Shokier Mohamed SoltanMohamed Soltan More articles by this author , Ahmed AbdelhalimAhmed Abdelhalim More articles by this author , Ahmed ElkashefAhmed Elkashef More articles by this author , Mohamed EdwanMohamed Edwan More articles by this author , Ahmed AtwaAhmed Atwa More articles by this author , Mohamed Abou-El_GharMohamed Abou-El_Ghar More articles by this author , Tamer HelmyTamer Helmy More articles by this author , Ashraf TarekAshraf Tarek More articles by this author , Mohamed DawabaMohamed Dawaba More articles by this author , and Ahmed ShokierAhmed Shokier More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002550.07AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Uretero-pelvic junction obstruction (UPJO) is the commonest cause of obstructive uropathy in children. Timing of surgical intervention is debatable, meanwhile the effect of delay surgical intervention is not well understood. The objective of the study is to identify surgery delay effect on renal function in cases of UPJO and factors affecting it. METHODS: Data base of patients who underwent pyeloplasty for unilateral UPJO in a tertiary center from January 2016 to October 2020 was reviewed. Patients who had a delay in pyeloplasty for more than 3 months from time of diagnosis were identified. Patients for whom 3 renograms were performed at the time of surgical decision, immediately before surgery and within 1 year postoperative were included in the study. Deterioration was defined as 5 % or more decline in the split renal function SRF between 2 consecutive renograms.Patients were then categorized into 2 groups: preserved renal function (group 1) and deteriorated renal function (group 2) based on the difference in preoperative renograms. Both groups were compared regarding pre and postoperative Antero-posterior diameter (APD), hydronephrosis grading, percent of change of hydronephrosis, change in SRF, and delay duration in months. RESULTS: A total 46 patients were included in the analysis: 30 cases had preserved renal function while 16 had significant deterioration of SRF. Group 2 showed higher precent increase of APD and more delay in surgical intervention (table) on univariate analysis (P value 0.016 and 0.001 respectively). On multivariate analysis these factors showed significant difference between groups. Other factors did not show significant difference between the groups. No significant difference was found in postoperative change of SRF. None of the patients who had surgery within 6 months showed functional deterioration. CONCLUSIONS: Delaying of surgical intervention for less than 6 months doesn`t lead to significant functional deterioration. Worsening hydronephrosis precedes functional deterioration. Source of Funding: No © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e286 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Mohamed Soltan More articles by this author Ahmed Abdelhalim More articles by this author Ahmed Elkashef More articles by this author Mohamed Edwan More articles by this author Ahmed Atwa More articles by this author Mohamed Abou-El_Ghar More articles by this author Tamer Helmy More articles by this author Ashraf Tarek More articles by this author Mohamed Dawaba More articles by this author Ahmed Shokier More articles by this author Expand All Advertisement PDF DownloadLoading ...

MP17-08 ATTAINING COMPETENCY AND PROFICIENCY IN OPEN PYELOPLASTY: A LEARNING CURVE CONFIGURATION USING CUMULATIVE SUM ANALYSIS

You have accessJournal of UrologyCME1 May 2022MP17-08 ATTAINING COMPETENCY AND PROFICIENCY IN OPEN PYELOPLASTY: A LEARNING CURVE CONFIGURATION USING CUMULATIVE SUM ANALYSIS Jin Kyu (Justin) Kim, Michael Chua, Mandy Rickard, Karen Milford, Daniel Keefe, and Armando Lorenzo Jin Kyu (Justin) KimJin Kyu (Justin) Kim More articles by this author , Michael ChuaMichael Chua More articles by this author , Mandy RickardMandy Rickard More articles by this author , Karen MilfordKaren Milford More articles by this author , Daniel KeefeDaniel Keefe More articles by this author , and Armando LorenzoArmando Lorenzo More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002550.08AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The learning curves for minimally invasive pyeloplasty techniques have been described in the past. However, the learning curve in achieving competency in open pyeloplasty has not been described. Hence, we aim to evaluate a single surgeon series of open pyeloplasty technique using the cumulative sum (CUSUM) methodology. METHODS: We retrospectively reviewed all open pyeloplasties performed by a single surgeon between January 2008 and March 2020. Collected variables included: sex, age at surgery, operative time, hospital stay, pre-operative ultrasound, pre-operative nuclear scans, pre-operative anteroposterior diameter, associated anomalies, laterality (left or right), type of stent, pre-operative split renal function, and duration of follow up. A CUSUM analysis was used: the highest peak, plateau and downward trends for complications (defined as Clavien-Dindo classification ≥ 3) were identified on the plot and set as the transition points between five phases (learning, competency, proficiency, case-mix, and mastery). RESULTS: Based on the CUSUM analysis, the index surgeon reached the competency phase after performing their 13th open pyeloplasty and became proficient after the 70th case. In the case-mix phase (104th to 126th cases), where the surgeon may be performing more complex cases while increasing trainee involvement, there was a slight increase in complication rates. After the 126th case, the surgeon entered the mastery phase, where there was consistent decreasing trend in complications (Table 1; Figure 1). CONCLUSIONS: Surgeons performing open pyeloplasty in children following completion of their surgical training will continue to learn through their early cases until achieving competency. Technical competency may be reached after the 13th case. Source of Funding: None © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e287 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Jin Kyu (Justin) Kim More articles by this author Michael Chua More articles by this author Mandy Rickard More articles by this author Karen Milford More articles by this author Daniel Keefe More articles by this author Armando Lorenzo More articles by this author Expand All Advertisement PDF DownloadLoading ...

Full-space terahertz regulation metasurface

Digital coded metasurface has greatly simplified the method for electromagnetic wave regulation. However, the traditional metasurface usually focuses on the half-space beam modulation, such as transmissive or reflective direction regulation, which hinders the application of the metasurface-based device. We proposed a full-space terahertz regulation metasurface, which can realize the functions of beam splitting, vortex beam convolution, and focusing for both transmissive and reflective modes. Furthermore, the transmission and reflection modes can be easily switched by changing the external temperature of vanadium dioxide. The presented structure shows excellent performance of full-space terahertz regulation. This method provides a new idea for multifunctional terahertz devices and can be exploited in applications where active manipulation of terahertz transmission direction is required.

Imbalanced learning for insurance using modified loss functions in tree-based models

Tree-based models have gained momentum in insurance claim loss modeling; however, the point mass at zero and the heavy tail of insurance loss distribution pose the challenge to apply conventional methods directly to claim loss modeling. With a simple illustrative dataset, we first demonstrate how the traditional tree-based algorithm's splitting function fails to cope with a large proportion of data with zero responses. To address the imbalance issue presented in such loss modeling, this paper aims to modify the traditional splitting function of Classification and Regression Tree (CART). In particular, we propose two novel modified loss functions, namely, the weighted sum of squared error and the sum of squared Canberra error. These modified loss functions impose a significant penalty on grouping observations of non-zero response with those of zero response at the splitting procedure, and thus significantly enhance their separation. Finally, we examine and compare the predictive performance of such modified tree-based models to the traditional model on synthetic datasets that imitate insurance loss. The results show that such modification leads to substantially different tree structures and improved prediction performance.

Parton distribution function in a pion with Minkowskian dynamics

The parton distribution of the pion is obtained for the first time from the solution of a dynamical equation in Minkowski space. The adopted equation is the homogeneous Bethe-Salpeter one with a ladder kernel, described in terms of (i) constituent quarks and gluons degrees of freedom, and (ii) an extended quark-gluon vertex. The masses of quark and gluon as well as the interaction-vertex scale have been chosen in a range suggested by lattice QCD calculations, and calibrated to reproduce both pion mass and decay constant. In addition to the full parton distribution, we have also calculated the contribution from the light-front valence wave function, corresponding to the lowest Fock component in the expansion of the pion state. After applying an evolution with an effective charge and a LO splitting function, a detailed and inspiring comparison with both the extracted experimental data (with and without resummation effects) and other recent calculations obtained in different frameworks is presented. Interestingly, in a wide region of longitudinal-momentum fraction, the parton distribution function receives sizable contributions from the higher Fock-components of the pion state at the initial scale, while approaching the tail the light-front valence component dominates, as expected. Moreover, an exponent $\ensuremath{\sim}3$ is found suitable for describing the tail at the scale 5.2 GeV.

A Phenomenological Approach to Multi-Higgs Production at High Energy

We tackle the issue of the factorial growth in the amplitudes of multi-Higgs production at high energy by developing a phenomenological approach based on the Higgs splitting functions and Sudakov factors. We utilize the method of generating functionals to define several jet observables for the Higgs sector. Our results suggest that pure Higgs splittings should retain a good Ultraviolet (UV) behavior in contrast to the common picture represented by the breakdown of perturbation theory and the violation of unitarity due to the high multiplicity of particles produced at or near threshold, which is found in scalar theories. We thus argue that the issue of the factorial growth in the amplitude of multi-Higgs production is probably associated with applying perturbation theory in a regime where it is no longer valid and with the n\(\lambda\) \(\to\) \(\infty\) limit, as opposed to being a sign of new physics.

Sign-free determinant quantum Monte Carlo study of excitonic density orders in a two-orbital Hubbard-Kanamori model

While excitonic instabilities in multiorbital systems recently have come under scrutiny in a variety of transition-metal compounds, understanding emergence of these instabilities from strong electronic interactions has remained a challenge. Here, we present a sign-problem-free determinant quantum Monte Carlo study of excitonic density orders in a half-filled two-orbital Hubbard-Kanamori model with broken orbital degeneracy, which accounts for the role of Hund's coupling in transition-metal compounds. For strong inverted (negative) Hund's exchange, we find numerical evidence for the emergence of excitonic density order, with competition between anti-ferro-orbital order and $\mathbf{Q} = (\pi,\pi)$ excitonic density order as a function of orbital splitting and Hund's coupling. While inverted Hund's coupling stabilizes a spin-singlet excitonic density phase for weak orbital splitting, positive Hund's coupling favors a spin-triplet excitonic density phase.

Explainable machine learning of the underlying physics of high-energy particle collisions

We present an implementation of an explainable and physics-aware machine learning model capable of inferring the underlying physics of high-energy particle collisions using the information encoded in the energy-momentum four-vectors of the final state particles. We demonstrate the proof-of-concept of our White Box AI approach using a Generative Adversarial Network (GAN) which learns from a DGLAP-based parton shower Monte Carlo event generator. The constrained generator network architecture mimics the structure of a parton shower exhibiting similarities with Recurrent Neural Networks (RNNs). We show, for the first time, that our approach leads to a network that is able to learn not only the final distribution of particles, but also the underlying parton branching mechanism, i.e. the Altarelli-Parisi splitting function, the ordering variable of the shower, and the scaling behavior. While the current work is focused on perturbative physics of the parton shower, we foresee a broad range of applications of our framework to areas that are currently difficult to address from first principles in QCD. Examples include nonperturbative and collective effects, factorization breaking and the modification of the parton shower in heavy-ion, and electron-nucleus collisions.