Oblique view individual tree crown delineation Kempf, Christian; Tian, Jiaojiao; Kurz, Franz ...
International journal of applied earth observation and geoinformation,
July 2021, Volume:
99
Journal Article
Peer reviewed
Open access
Display omitted
•A novel approach to oblique view delineation of individual trees is proposed.•Images at zenit angles from 0 to 53 degrees were acquired with the multi-stereo camera system 3K.•A ...deciduous, coniferous and a mixed region was selected for experimental evaluation of the method.•Active Contours is combined with the Watershed Transform for DSM segmentation.•Oblique view image delineation is derived using Ray Casting and Alpha Shape calculation.
Individual tree crown (ITC) segmentation supports numerous applications in forest management and ecology. In the latter context, special attention is dedicated to the study of angular reflection effects, caused by the interaction of incident sunlight with a canopy. High precision airborne analysis of these effects requires multi-view sensor systems and multi-view ITC segmentation. In particular oblique view image segmentation is difficult and has been addressed by numerous template based methods. This contribution identifies persistent shortcomings in the state of the art and tackles the problem by a multi-step workflow utilizing the digital surface model (DSM), derived from multi-view stereo data. A slightly revised version of the previously published levelset-watershed segmentation of the DSM is presented as the first step. In the second step, the contour of the visible part of a candidate tree in images with known orientation is obtained by means of ray casting and concave hull calculation. The method was tested on a deciduous, mixed and coniferous plot, whose aerial images were acquired using the 3K camera system in 2018 at Kranzberg Forest, Bavaria, Germany. Accuracies were assessed at hand of human operator generated groundtruth tree tops for the DSM as well as images with zenit angles of approximately 0,45 and 52 degrees. The resulting F1-scores, averaged over the plots, are 0.909/0.902/0.886/0.876 for the DSM/near-nadir-/oblique-/maximum-oblique-images, respectively.
Activity deprivation in neurons induces a slow compensatory scaling up of synaptic strength, reflecting a homeostatic mechanism for stabilizing neuronal activity. Prior studies have focused on the ...loss of action potential (AP) driven neurotransmission in synaptic homeostasis. Here, we show that the miniature synaptic transmission that persists during AP blockade profoundly shapes the time course and mechanism of homeostatic scaling. A brief blockade of NMDA receptor (NMDAR) mediated miniature synaptic events (“minis”) rapidly scales up synaptic strength, over an order of magnitude faster than with AP blockade alone. The rapid scaling induced by NMDAR mini blockade is mediated by increased synaptic expression of surface GluR1 and the transient incorporation of Ca
2+-permeable AMPA receptors at synapses; both of these changes are implemented locally within dendrites and require dendritic protein synthesis. These results indicate that NMDAR signaling during miniature synaptic transmission serves to stabilize synaptic function through active suppression of dendritic protein synthesis.
Real-world comparisons of biologic treatment outcomes for ulcerative colitis (UC) or Crohn's disease (CD) patients are limited. We sought to evaluate the real-world effectiveness of vedolizumab (VDZ) ...and anti-tumor necrosis factor alpha (anti-TNFα) in UC and CD patients in Germany.
A retrospective chart review (15 sites) investigated UC and CD patients who were biologic-treatment naïve (biologic-naïve) or had received no more than one prior anti-TNFα before initiating treatment with VDZ or anti-TNFα between 15 July 2014 and 20 October 2015. Kaplan-Meier analyses assessed time to first chart-documented clinical remission (CR) and symptom resolution (UC: rectal bleeding RB, stool frequency SF; CD: abdominal pain AP, liquid stools LS) and outcome duration.
A total of 133 UC (76 VDZ; 57 anti-TNFα) and 174 CD (69 VDZ; 105 anti-TNFα) patients were included. By Week 26, estimated cumulative rates of patients achieving CR or symptom resolution with VDZ vs anti-TNFα treatment were for UC: CR, 53.7% vs 31.7%; RB, 66.8% vs 55.8%; and SF, 59.8% vs 50.7%, respectively; and for CD: CR, 14.4% vs 32.8%; AP, 62.5% vs 56.0%; and LS, 29.9% vs 50.3%, respectively. Outcomes were sustained similarly between treatments, except RB (VDZ vs anti-TNFα: median 38.1 vs 15.1 weeks, P = 0.03). Treatment-related adverse events occurred in 5.3% vs 7.0% (UC) and 8.7% vs 19.0% (CD) of VDZ vs anti-TNFα patients, respectively.
Although there were differences in CR, symptom resolution, and safety profiles, real-world data support both VDZ and anti-TNFα as effective treatment options in UC and CD.
Introduction:
Thromboembolic events, including ischemic stroke, are major complications of coronavirus disease 2019 (COVID-19). The clinical characteristics of COVID-19-related stroke are not clearly ...defined, and few controlled studies assessed the underlying mechanisms of cerebrovascular complications of COVID-19. This single-center retrospective observational study compared stroke characteristics between patients with and without COVID-19.
Methods:
This study included all patients hospitalized between March 1, 2020, and April 30, 2020, in Colmar Hospital for ischemic stroke as confirmed by imaging. The characteristics of patients with laboratory-confirmed severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection by real-time reverse transcriptase polymerase chain reaction or serology were compared with those without SARS-CoV-2 infection.
Result:
Among 772 patients, nine COVID-19 patients were compared with 50 patients without COVID-19. The following inflammatory and procoagulant marker levels were significantly higher in the COVID-19 group than those in the control group: C-reactive protein, 57.3 ± 43.4 vs. 15.0 ± 30.6 mg/L,
p
< 0.001; fibrinogen, 5.89 ± 1.75 vs. 4.03 ± 1.26 g/L,
p
< 0.001; and D-dimer, 4,833.9 ± 6,549.4 vs. 1,028.6 ± 942.6 ng/ml,
p
< 0.001. The rates of multifocal cerebral territory involvement (4 vs. 7,
p
= 0.05), microvascular involvement (4 vs. 6,
p
= 0.04), and thrombophilia (4 vs. 4,
p
= 0.014) were significantly higher in the COVID-19 group than in the control group, whereas no significant intergroup differences were found in the stroke mechanisms, i.e., cardio-embolic, atherosclerotic, small vessel disease, and cryptogenic.
Conclusion:
COVID-19-related stroke is characterized by hypercoagulability and hyperinflammation that may favor strokes via microvascular circulation abnormalities, microthrombus formation, and multifocal lesions.
The calyx of Held, a large glutamatergic terminal in the mammalian auditory brainstem has been extensively employed to study presynaptic structure and function in the central nervous system. ...Nevertheless, the nanoarchitecture of presynaptic proteins and subcellular components in the calyx terminal and its relation to functional properties of synaptic transmission is only poorly understood. Here, we use stimulated emission depletion (STED) nanoscopy of calyces in thin sections of aldehyde-fixed rat brain tissue to visualize immuno-labeled synaptic proteins including VGluT1, synaptophysin, Rab3A and synapsin with a lateral resolution of approximately 40 nm. Excitation multiplexing of suitable fluorescent dyes deciphered the spatial arrangement of the presynaptic phospho-protein synapsin relative to synaptic vesicles labeled with anti-VGluT1. Both predominantly occupied the same focal volume, yet may exist in exclusive domains containing either VGluT1 or synapsin immunoreactivity. While the latter have been observed with diffraction-limited fluorescence microscopy, STED microscopy for the first time revealed VGluT1-positive domains lacking synapsins. This observation supports the hypothesis that molecularly and structurally distinct synaptic vesicle pools operate in presynaptic nerve terminals.
Nosocomial coronavirus disease 2019 (COVID-19) is a major airborne health threat for inpatients. Architecture and ventilation are key elements to prevent nosocomial COVID-19 (NC), but real-life data ...are challenging to collect. We aimed to retrospectively assess the impact of the type of ventilation and the ratio of single/double rooms on the risk of NC (acquisition of COVID-19 at least 48 h after admission). This study was conducted in a tertiary hospital composed of two main structures (one historical and one modern), which were the sites of acquisition of NC: historical (H) (natural ventilation, 53% single rooms) or modern (M) hospital (double-flow mechanical ventilation, 91% single rooms). During the study period (1 October 2020 to 31 May 2021), 1020 patients presented with COVID-19, with 150 (14.7%) of them being NC (median delay of acquisition, 12 days). As compared with non-nosocomial cases, the patients with NC were older (79 years vs. 72 years;
< 0.001) and exhibited higher mortality risk (32.7% vs. 14.1%;
< 0.001). Among the 150 NC cases, 99.3% were diagnosed in H, mainly in four medical departments. A total of 73 cases were diagnosed in single rooms versus 77 in double rooms, including 26 secondary cases. Measured air changes per hour were lower in H than in M. We hypothesized that in H, SARS-CoV-2 transmission was favored by short-range transmission within a high ratio of double rooms, but also during clusters, via far-afield transmission through virus-laden aerosols favored by low air changes per hour. A better knowledge of the mechanism of airborne risk in healthcare establishments should lead to the implementation of corrective measures when necessary. People's health is improved using not only personal but also collective protective equipment, i.e., ventilation and architecture, thereby reinforcing the need to change institutional and professional practices.
Posttransplant lymphoproliferative disorder (PTLD) involves uncommon, severe complications following the transplantation of solid organs, bone marrow and stem cells. Despite comprising mainly ...lymphoid proliferations that are predominantly driven by lymphotropic Epstein-Barr virus (EBV) infections, PTLD often displays substantial morphologic heterogeneity that can pose diagnostic challenges. With the steady increase in transplantations accompanied by potent immunosuppressive therapy, it is important to heighten awareness of this entity among clinicians and pathologists. In comparison to systemic PTLD, cases that primarily manifest in the central nervous system (CNS) are reported to be more severe and to exhibit unique characteristics. So far, only isolated cases and small series have been reported describing CNS involvement in PTLD. In this article, we review the current knowledge, focusing on the histopathological features of primary CNS lymphoproliferative disorders following organ transplantation.
Hypertension, a risk factor for cardiovascular disease (CVD), is frequently associated with other CVD risk factors. Despite recent improvement in blood pressure (BP) control in Europe, a substantial ...proportion of patients fail to achieve BP targets.
This retrospective cohort study used longitudinal patient databases (LPDs) in France and Italy to examine CVD risk profiles, treatment patterns, and BP goal attainment in hypertensive patients treated in real-world clinical practice between 2007 and 2008. Overall, 147,964 and 140,189 eligible patients from LPDs in France and Italy, respectively, were prescribed an antihypertensive medication in 2007.
Among patients with hypertension with other risk factors (France 88 %, Italy 83 %), the most prevalent risk factors were being elderly (France 66.9 %, Italy 70. 9 %), followed by hypertension combined with dyslipidemia (France 36.7 %, Italy 23.9 %) and isolated systolic hypertension (France 32.5 %, Italy 24.2 %). The odds ratios for target BP attainment were significantly (p < 0.001) higher in patients with hypertension without other risk factors vs patients with hypertension with other risk factors (1.41 95 % confidence interval 1.35, 1.48 in France; 1.38 1.31, 1.46 in Italy). The odds of BP control were significantly lower for patients with vs patients without an associated CVD risk factor (range 0.54 to 1.10 France; 0.59 to 1.17 Italy).
This study demonstrates that the majority of treated hypertensive patients in France and Italy have at least one additional CVD risk factor. Despite treatment with antihypertensive medications, blood pressure attainment was substantially less optimal in patients with an associated CVD risk factor compared to patients without an associated CVD risk factor.
Background. The perception of the role of caregivers for people with multiple sclerosis (MS) is important but poorly studied, particularly in patients with low levels of disability. Objectives. To ...describe the perceptions of the role of caregivers from the perspective of the caregiver, the patient, and neurologists. Methods. This observational study was conducted in France on patients with relapsing remitting MS treated with subcutaneous (SC) interferon-β-1a (IFN-β-1a) for more than 24 months. Results. Caregiver, patients, and neurologists all considered providing moral support and fighting against the disease as the most important role of the care provider. Moral support was considered significantly more important by caregivers than the patients and neurologists ( p = 0.002 ) and caregivers considered their role in helping patients to fight disease more important than did the neurologists ( p = 0.006 ). Knowledge of disease and available treatments were less important among support providers than patients ( p = 0.007 and p = 0.001 ). Conclusion. There are many unmet needs in the perception of the role of caregivers for people with MS which need to be addressed to deliver the most effective care package for patients and to support the needs of the support provider.
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