Defects in active nematics: algorithms for identification and tracking

The growing interest in active nematics and the emerging evidence of the relevance of topological defects in biology asks for reliable data analysis tools to identify, classify and track such defects in simulation and microscopy data. We here provide such tools and demonstrate on two examples, on an active turbulent state in an active nematodynamic model and on emerging nematic order in a multi-phase field model, the possibility to compare statistical data on defect velocities with experimental results. The considered tools, which are physics based and data driven, are compared with each other.Comment: 13 pages, 6 figure

Novel UAV Flight Designs for Accuracy Optimization of Structure from Motion Data Products

Leveraging low-cost drone technology, specifically the DJI Mini 2, this study presents an innovative method for creating accurate, high-resolution digital surface models (DSMs) to enhance topographic mapping with off-the-shelf components. Our research, conducted near Jena, Germany, introduces two novel flight designs, the “spiral” and “loop” flight designs, devised to mitigate common challenges in structure from motion workflows, such as systematic doming and bowling effects. The analysis, based on height difference products with a lidar-based reference, and curvature estimates, revealed that “loop” and “spiral” flight patterns were successful in substantially reducing these systematic errors. It was observed that the novel flight designs resulted in DSMs with lower curvature values compared to the simple nadir or oblique flight patterns, indicating a significant reduction in distortions. The results imply that the adoption of novel flight designs can lead to substantial improvements in DSM quality, while facilitating shorter flight times and lower computational needs. This work underscores the potential of consumer-grade unoccupied aerial vehicle hardware for scientific applications, especially in remote sensing tasks

Tree Stem Detection and Crown Delineation in a Structurally Diverse Deciduous Forest Combining Leaf-On and Leaf-Off UAV-SfM Data

Accurate detection and delineation of individual trees and their crowns in dense forest environments are essential for forest management and ecological applications. This study explores the potential of combining leaf-off and leaf-on structure from motion (SfM) data products from unoccupied aerial vehicles (UAVs) equipped with RGB cameras. The main objective was to develop a reliable method for precise tree stem detection and crown delineation in dense deciduous forests, demonstrated at a structurally diverse old-growth forest in the Hainich National Park, Germany. Stem positions were extracted from the leaf-off point cloud by a clustering algorithm. The accuracy of the derived stem co-ordinates and the overall UAV-SfM point cloud were assessed separately, considering different tree types. Extracted tree stems were used as markers for individual tree crown delineation (ITCD) through a region growing algorithm on the leaf-on data. Stem positioning showed high precision values (0.867). Including leaf-off stem positions enhanced the crown delineation, but crown delineations in dense forest canopies remain challenging. Both the number of stems and crowns were underestimated, suggesting that the number of overstory trees in dense forests tends to be higher than commonly estimated in remote sensing approaches. In general, UAV-SfM point clouds prove to be a cost-effective and accurate alternative to LiDAR data for tree stem detection. The combined datasets provide valuable insights into forest structure, enabling a more comprehensive understanding of the canopy, stems, and forest floor, thus facilitating more reliable forest parameter extraction

Discrepancy between German S3 Guideline Recommendations and Daily Urologic Practice in the Management of Nonmuscle Invasive Bladder Cancer: Results of a Binational Survey

Introduction: Guideline recommendations are meant to help minimize morbidity and to improve the care of nonmuscle invasive bladder cancer (NMIBC) patients but studies have suggested an underuse of guideline-recommended care. The aim of this study was to evaluate the level of adherence of German and Austrian urologists to German guideline recommendations. Methods: A survey of 27 items evaluating diagnostic and therapeutic recommendations (15 cases of strong consensus and 6 cases of consensus) for NMIBC was administered among 14 urologic training courses. Survey construction and realization followed the checklist for reporting results of internet e-surveys and was approved by an internal review board. Results: Between January 2018 and June 2019, a total of 307 urologists responded to the questionnaire, with a mean response rate of 71%. The data showed a weak role of urine cytology (54%) for initial diagnostics although it is strongly recommended by the guideline. The most frequently used supporting diagnostic tool during transurethral resection of the bladder was hexaminolevulinate (95%). Contrary to the guideline recommendation, 38% of the participants performed a second resection in the case of pTa low-grade NMIBC. Correct monitoring of Bacille Calmette-Guerin (BCG) response with cystoscopy and cytology was performed by only 34% of the urologists. Conclusions: We found a discrepancy between certain guideline recommendations and daily routine practice concerning the use of urine cytology for initial diagnostics, instillation therapy with a low monitoring rate of BCG response, and follow-up care with unnecessary second resection after pTa low-grade NMIBC in particular. Our survey showed a moderate overall adherence rate of 73%. These results demonstrate the need for sharpening awareness of German guideline recommendations by promoting more intense education of urologists to optimize NMIBC care thus decreasing morbidity and mortality rates

Robotic Stereotactic Radiosurgery in Melanoma Patients with Brain Metastases under Simultaneous Anti-PD-1 Treatment

Combination concepts of radiotherapy and immune checkpoint inhibition are currently of high interest. We examined imaging findings, acute toxicity, and local control in patients with melanoma brain metastases receiving programmed death 1 (PD-1) inhibitors and/or robotic stereotactic radiosurgery (SRS). Twenty-six patients treated with SRS alone (n = 13;20 lesions) or in combination with anti-PD-1 therapy (n = 13;28 lesions) were analyzed. Lesion size was evaluated three and six months after SRS using a volumetric assessment based on cranial magnetic resonance imaging (cMRI) and acute toxicity after 12 weeks according to the Common Terminology Criteria for Adverse Events (CTCAE). Local control after six months was comparable (86%, SRS + anti-PD-1, and 80%, SRS). All toxicities reported were less than or equal to grade 2. One metastasis (5%) in the SRS group and six (21%) in the SRS + anti-PD-1 group increased after three months, whereas four (14%) of the six regressed during further follow-ups. This was rated as pseudoprogression (PsP). Three patients (23%) in the SRS + anti-PD-1 group showed characteristics of PsP. Treatment with SRS and anti-PD-1 antibodies can be combined safely in melanoma patients with cerebral metastases. Early volumetric progression of lesions under simultaneous treatment may be related to PsP;thus, the evaluation of combined radioimmunotherapy remains challenging and requires experienced teams

Sex difference and intra-operative tidal volume: Insights from the LAS VEGAS study

BACKGROUND: One key element of lung-protective ventilation is the use of a low tidal volume (VT). A sex difference in use of low tidal volume ventilation (LTVV) has been described in critically ill ICU patients.OBJECTIVES: The aim of this study was to determine whether a sex difference in use of LTVV also exists in operating room patients, and if present what factors drive this difference.DESIGN, PATIENTS AND SETTING: This is a posthoc analysis of LAS VEGAS, a 1-week worldwide observational study in adults requiring intra-operative ventilation during general anaesthesia for surgery in 146 hospitals in 29 countries.MAIN OUTCOME MEASURES: Women and men were compared with respect to use of LTVV, defined as VT of 8 ml kg-1 or less predicted bodyweight (PBW). A VT was deemed 'default' if the set VT was a round number. A mediation analysis assessed which factors may explain the sex difference in use of LTVV during intra-operative ventilation.RESULTS: This analysis includes 9864 patients, of whom 5425 (55%) were women. A default VT was often set, both in women and men; mode VT was 500 ml. Median [IQR] VT was higher in women than in men (8.6 [7.7 to 9.6] vs. 7.6 [6.8 to 8.4] ml kg-1 PBW, P < 0.001). Compared with men, women were twice as likely not to receive LTVV [68.8 vs. 36.0%; relative risk ratio 2.1 (95% CI 1.9 to 2.1), P < 0.001]. In the mediation analysis, patients' height and actual body weight (ABW) explained 81 and 18% of the sex difference in use of LTVV, respectively; it was not explained by the use of a default VT.CONCLUSION: In this worldwide cohort of patients receiving intra-operative ventilation during general anaesthesia for surgery, women received a higher VT than men during intra-operative ventilation. The risk for a female not to receive LTVV during surgery was double that of males. Height and ABW were the two mediators of the sex difference in use of LTVV.TRIAL REGISTRATION: The study was registered at Clinicaltrials.gov, NCT01601223

Digital forest inventory based on UAV imagery

Data on forest parameters defining the structure, health and condition of a forest stand is essential for forest management and conservation. The increasing frequency of forest changes, such as those caused by climate change-related drought and heat events, highlight the importance of having a forest database with high spatial and temporal resolution. Automated forest parameter extraction based on unmanned aerial vehicle (UAV) imagery is a cost-effective way to address the need for accurate and up-to-date forest data. The aim of this project is to develop user-friendly tools based on optical data from UAVs that can be applied to accurately and efficiently conduct digital forest inventories. We are using spectral and geometric information from UAV data to create methods for automated derivation of forest parameters such as diameter at breast height (DBH), tree stem positions, individual tree crown delineation, and coarse wood debris. These methods are being designed with the practical needs of potential users from the forestry sector in mind. Different flight configurations, such as nadir and oblique camera angles, as well as different acquisition times, were combined to generate structure from motion (SfM) data products (dense 3D point clouds, orthomosaics and height models) containing both ground and canopy information. For a study site within the Hainich National Park, Germany, we analyzed how leaf-off and leaf-on data can be combined to improve the derivation of stand parameters, such as tree stem positions and individual tree crowns, using point- and raster-based algorithms. Additionally, DBH on an individual tree basis was derived for the same study site using the cast shadows of tree trunks. To do so, a deep learning model was trained to identify stem shadows based on an orthomosaic of only ground points acquired during sunny and leaf-off conditions

Digital forest inventory by drone: Mapping DBH in UAV data from tree stem shadow features

Forest inventories are traditionally conducted at regular time intervals during field campaigns measuring trees manually. In general, a small subset of trees is selected for data collection, information about the whole forest stand is obtained by extrapolation. These methods are time-consuming and tend to be accompanied by great uncertainties as the sample might not be representative for a heterogenous forest stand. At the same time, developments within the German forestry sector reinforce the need for an accurate and up-to-date forest data base even more: a) large-scale forest damage due to climate change related drought and heat events b) lack of personnel in parts of the forestry sector c) tendencies of a forest conversion from monoculture stand to more mixed forest areas d) an increasing digitalization strategy being pursued. To address this need, structure from motion (SfM) data products acquired using unmanned aerial vehicles (UAV) are a cost-effective method to derive forest parameters. In the "Shadow" project spectral and geometric information from UAV data is being used to develop methods for automated derivation of forest parameters such as diameter at breast height (DBH), tree stem positions, individual tree crown delineation, coarse wood debris, etc. as well as secondary parameter like timber stock. One focus of the method development within the project is its orientation to user-friendly tools and practical needs of potential users of digital inventory methods. So far, for example stem coordinates and crown delineation could be generated using a combination of leaf-off and leaf-on UAV data sets and point cloud-based algorithms. Also, the DBH as an important forest parameter, e.g. for estimating wood supply, biomass and stem growth rates, has been derived using classified cast shadows of tree trunks. Leaf-off data has been acquired over a deciduous forest stand near Jena and in the Hainich National Park, Germany, during sunny weather conditions. Using SfM a point cloud has been generated from the UAV images and normalized with respect to the relief. Points belonging to the tree canopy and stems are removed resulting in an orthomosaic image containing only ground information. In a second step, deep learning models have been tested to achieve an automatic detection and delineation of cast shadows. As the shape of the cast shadow and of the stem are correlated, parameters such as DBH can be derived from the detected shadows

Clinical characteristics, treatment patterns and relapse in patients with clinical stage IS testicular cancer

Purpose Clinical stage I (CSI) testicular germ cell tumors (TGCT) represents disease confined to the testis without metastasis and CSIS is defined as persistently elevated tumor markers (TM) after orchiectomy, indicating subclinical metastatic disease. This study aims at assessing clinical characteristics and oncological outcome in CSIS. Methods Data from five tertiary referring centers in Germany were screened. We defined correct classification of CSIS according to EAU guidelines. TM levels, treatment and relapse-free survival were assessed and differences between predefined groups (chemotherapy, correct/incorrect CSIS) were analyzed with Fisher's exact and Chi-square test. Results Out of 2616 TGCT patients, 43 (1.6%) were CSIS. Thereof, 27 were correctly classified (cCSIS, 1.03%) and 16 incorrectly classified (iCSIS). TMs that defined cCSIS were in 12 (44.4%), 10 (37%), 3 (11.1%) and 2 (7.4%) patients AFP, ss-HCG, AFP plus ss-HCG and LDH, respectively. In the cCSIS group, six patients were seminoma and 21 non-seminoma. Treatment consisted of active surveillance, carboplatin-mono AUC7 and BEP (bleomycin, etoposide and cisplatin). No difference between cCSIS and iCSIS with respect to applied chemotherapy was found (p = 0.830). 5-year relapse-free survival was 88.9% and three patients (11%) in the cCSIS group relapsed. All underwent salvage treatment (3xBEP) with no documented death. Conclusion Around 1% of all TGCT were classified as cCSIS patients. Identification of cCSIS is of critical importance to avoid disease progression and relapses by adequate treatment. We report a high heterogeneity of treatment patterns, associated with excellent long-term survival irrespective of the initial treatment approach