Optimization in Differentiable Manifolds in Order to Determine the Method of Construction of Prehistoric Wall-Paintings

In this paper a general methodology is introduced for the determination of potential prototype curves used for the drawing of prehistoric wall-paintings. The approach includes a) preprocessing of the wall-paintings contours to properly partition them, according to their curvature, b) choice of prototype curves families, c) analysis and optimization in 4-manifold for a first estimation of the form of these prototypes, d) clustering of the contour parts and the prototypes, to determine a minimal number of potential guides, e) further optimization in 4-manifold, applied to each cluster separately, in order to determine the exact functional form of the potential guides, together with the corresponding drawn contour parts. The introduced methodology simultaneously deals with two problems: a) the arbitrariness in data-points orientation and b) the determination of one proper form for a prototype curve that optimally fits the corresponding contour data. Arbitrariness in orientation has been dealt with a novel curvature based error, while the proper forms of curve prototypes have been exhaustively determined by embedding curvature deformations of the prototypes into 4-manifolds. Application of this methodology to celebrated wall-paintings excavated at Tyrins, Greece and the Greek island of Thera, manifests it is highly probable that these wall-paintings had been drawn by means of geometric guides that correspond to linear spirals and hyperbolae. These geometric forms fit the drawings' lines with an exceptionally low average error, less than 0.39mm. Hence, the approach suggests the existence of accurate realizations of complicated geometric entities, more than 1000 years before their axiomatic formulation in Classical Ages

Test-retest repeatability of organ uptake on PSMA‐targeted 18F‐DCFPyL PET/CT in patients with prostate cancer

Objectives We evaluated 18F-DCFPyL test–retest repeatability of uptake in normal organs. Methods Twenty-two prostate cancer (PC) patients underwent two 18F-DCFPyL PET scans within 7 days within a prospective clinical trial (NCT03793543). In both PET scans, uptake in normal organs (kidneys, spleen, liver, and salivary and lacrimal glands) was quantified. Repeatability was determined by using within-subject coefficient of variation (wCOV), with lower values indicating improved repeatability. Results For SUVmean, repeatability was high for kidneys, spleen, liver, and parotid glands (wCOV, range: 9.0%–14.3%) and lower for lacrimal (23.9%) and submandibular glands (12.4%). For SUVmax, however, the lacrimal (14.4%) and submandibular glands (6.9%) achieved higher repeatability, while for large organs (kidneys, liver, spleen, and parotid glands), repeatability was low (range: 14.1%–45.2%). Conclusion We found acceptable repeatability of uptake on 18F-DCFPyL PET for normal organs, in particular for SUVmean in the liver or parotid glands. This may have implications for both PSMA-targeted imaging and treatment, as patient selection for radioligand therapy and standardized frameworks for scan interpretation (PROMISE, E-PSMA) rely on uptake in those reference organs

Altenberg : inner landscapes

Zu der Publikation gehören mehrere Videodateien, die unter http://dx.doi.org/10.25819/fodasi/7 verfügbar sind. Zum Abspielen der Dateien wird ein Media-Player benötigt.Wenn man die Straße zwischen den beiden Siegerländer Dörfern Littfeld und Müsen fährt, überquert man in der Mitte eine Passhöhe: den Altenberg. Eine Sage berichtet, dass hier einst ein Dorf gestanden habe, das abgebrannt sei, als Strafe für die Habgier und den ausschweifenden Lebenswandel ihrer Bewohner. Nach einem Zufallsfund im Jahr 1963 erkundete man das Gelände archäologisch genauer und entdeckte Reste einer mittelalterlichen Siedlung und: Spuren ausgiebigen Silberbergbaus. Das Dorf war irgendwann aufgegeben worden, und die Natur hatte sich das Terrain über die Jahrhunderte zurückgeholt. Heute erinnern einzelne Überreste an Gebäude, Pingen und Schächte – ein magischer Platz, wo sich Natur und Kultur, uralte, vergessene und verborgene Geschichte und Gegenwart begegnen. Studierende der Fächer Architektur und Musik der Universität Siegen haben unter der Leitung von Prof. Ulrich Exner (Architektur) und Prof. Martin Herchenröder (Musik) das Gelände erforscht und dann auf das Gefundene mit künstlerischen Mitteln reagiert: In gemischten Arbeitsgruppen haben sie Filme komponiert, die einen neuen Blick auf das Gelände richten, den Altenberg neu interpretieren, ihn wieder lebendig werden lassen oder surreal verfremden, einzelne Aspekte hervorheben oder das Areal als Schauplatz und Hintergrund eigenwilliger Visionen verwenden – filmisch, architektonisch, musikalisch, performativ. Dabei spielt die reale Geschichte des Platzes ebenso in die Gestaltung hinein wie die Phantasie, die dieser Ort so mächtig anregt. Siegerländer Heimat-Videos, die es in sich haben… Buch (u.a. Projektdokumentation) und Videodatei.Aus dem Inhalt: Innere Landschaften = Inner Landscapes / Ulrich Exner und Martin Herchenröder SchURFACE : ein musikalischer Querschnitt = SchURFACE / Isabel Pazmann, Julia-Elisabeth Schander, Moritz Schönauer Klirrende Tiefen = Klirrende Tiefen (Clanging Depths) / Birk Arnold, Thomas Göbel Erdbrocken geträumt = Erdbrocken geträumt (Dreams of Clumped Earth) / Vivien Blecker, Till-Jonas Umbach Unentrinnbar und leise = Unentrinnbar und leise (Inescapable and silent) / Sarah Bäumer, Johanna Scheid, Daphne Schulte, Constantin Schwencke, Cora Theobald Hochmut = Hochmut (Pride) / Pia Bettig, Thomas Irnich, Nathanael Metenkanitch Bruch. Stück.Artig. = Bruch. Stück.Artig. (Frag. Ment. Like.) / Lena Hugger, Leonard Blümer, Julius Steuerwald-Ludwig, Cora Theobald NOVA = NOVA / Marco Hoffmann, Felix Ludewi

Lack of repeatability of radiomic features derived from PET scans: results from a 18F‐DCFPyL test–retest cohort

Objectives PET-based radiomic metrics are increasingly utilized as predictive image biomarkers. However, the repeatability of radiomic features on PET has not been assessed in a test–retest setting. The prostate-specific membrane antigen-targeted compound 18F-DCFPyL is a high-affinity, high-contrast PET agent that we utilized in a test-retest cohort of men with metastatic prostate cancer (PC). Methods Data of 21 patients enrolled in a prospective clinical trial with histologically proven PC underwent two 18F-DCFPyL PET scans within 7 days, using identical acquisition and reconstruction parameters. Sites of disease were segmented and a set of 29 different radiomic parameters were assessed on both scans. We determined repeatability of quantification by using Pearson's correlations, within-subject coefficient of variation (wCOV), and Bland–Altman analysis. Results In total, 230 lesions (177 bone, 38 lymph nodes, 15 others) were assessed on both scans. For all investigated radiomic features, a broad range of inter-scan correlation was found (r, 0.07–0.95), with acceptable reproducibility for entropy and homogeneity (wCOV, 16.0% and 12.7%, respectively). On Bland–Altman analysis, no systematic increase or decrease between the scans was observed for either parameter (±1.96 SD: 1.07/−1.30, 0.23/−0.18, respectively). The remaining 27 tested radiomic metrics, however, achieved unacceptable high wCOV (≥21.7%). Conclusion Many common radiomic features derived from a test–retest PET study had poor repeatability. Only Entropy and homogeneity achieved good repeatability, supporting the notion that those image biomarkers may be incorporated in future clinical trials. Those radiomic features based on high frequency aspects of images appear to lack the repeatability on PET to justify further study

High SUVs have more robust repeatability in patients with metastatic prostate cancer: results from a prospective test-retest cohort imaged with 18F-DCFPyL

OBJECTIVES: In patients with prostate cancer (PC) receiving prostate-specific membrane antigen- (PSMA-) targeted radioligand therapy (RLT), higher baseline standardized uptake values (SUVs) are linked to improved outcome. Thus, readers deciding on RLT must have certainty on the repeatability of PSMA uptake metrics. As such, we aimed to evaluate the test-retest repeatability of lesion uptake in a large cohort of patients imaged with (18)F-DCFPyL. METHODS: In this prospective, IRB-approved trial (NCT03793543), 21 patients with history of histologically proven PC underwent two (18)F-DCFPyL PET/CTs within 7 days (mean 3.7, range 1 to 7 days). Lesions in the bone, lymph nodes (LN), and other organs were manually segmented on both scans, and uptake parameters were assessed (maximum (SUV(max)) and mean (SUV(mean)) SUVs), PSMA-tumor volume (PSMA-TV), and total lesion PSMA (TL-PSMA, defined as PSMA − TV × SUV(mean))). Repeatability was determined using Pearson's correlations, within-subject coefficient of variation (wCOV), and Bland-Altman analysis. RESULTS: In total, 230 pairs of lesions (177 bone, 38 LN, and 15 other) were delineated, demonstrating a wide range of SUV(max) (1.5–80.5) and SUV(mean) (1.4–24.8). Including all sites of suspected disease, SUVs had a strong interscan correlation (R(2) ≥ 0.99), with high repeatability for SUV(mean) and SUV(max) (wCOV, 7.3% and 12.1%, respectively). High SUVs showed significantly improved wCOV relative to lower SUVs (P < 0.0001), indicating that high SUVs are more repeatable, relative to the magnitude of the underlying SUV. Repeatability for PSMA-TV and TL-PSMA, however, was low (wCOV ≥ 23.5%). Across all metrics for LN and bone lesions, interscan correlation was again strong (R(2) ≥ 0.98). Moreover, LN-based SUV(mean) also achieved the best wCOV (3.8%), which was significantly reduced when compared to osseous lesions (7.8%, P < 0.0001). This was also noted for SUV(max) (wCOV, LN 8.8% vs. bone 12.0%, P < 0.03). On a compartment-based level, wCOVs for volumetric features were ≥22.8%, demonstrating no significant differences between LN and bone lesions (PSMA-TV, P =0.63; TL-PSMA, P =0.9). Findings on an entire tumor burden level were also corroborated in a hottest lesion analysis investigating the SUV(max) of the most intense lesion per patient (R(2), 0.99; wCOV, 11.2%). CONCLUSION: In this prospective test-retest setting, SUV parameters demonstrated high repeatability, in particular in LNs, while volumetric parameters demonstrated low repeatability. Further, the large number of lesions and wide distribution of SUVs included in this analysis allowed for the demonstration of a dependence of repeatability on SUV, with higher SUVs having more robust repeatability

Jet stream position explains regional anomalies in European beech forest productivity and tree growth.

The mechanistic pathways connecting ocean-atmosphere variability and terrestrial productivity are well-established theoretically, but remain challenging to quantify empirically. Such quantification will greatly improve the assessment and prediction of changes in terrestrial carbon sequestration in response to dynamically induced climatic extremes. The jet stream latitude (JSL) over the North Atlantic-European domain provides a synthetic and robust physical framework that integrates climate variability not accounted for by atmospheric circulation patterns alone. Surface climate impacts of north-south summer JSL displacements are not uniform across Europe, but rather create a northwestern-southeastern dipole in forest productivity and radial-growth anomalies. Summer JSL variability over the eastern North Atlantic-European domain (5-40E) exerts the strongest impact on European beech, inducing anomalies of up to 30% in modelled gross primary productivity and 50% in radial tree growth. The net effects of JSL movements on terrestrial carbon fluxes depend on forest density, carbon stocks, and productivity imbalances across biogeographic regions

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700