785 research outputs found
Digitale Vegetationskartierung des Nationalparks Asinara (Sardinien)
Mit Methoden der Fernerkundung und der digitalen Bildanalyse wird eine digitale Vegetationskartierung fĂŒr die Mittelmeerinsel Asinara (Sardinien) durchgefĂŒhrt. Auf Grundlage von Feldarbeiten und hochauflösenden, multispektralen Satellitenbilddaten (PlĂ©iades, 2 x 2 m) wird eine pixelbasierte Ăberwachte Klassifizierung mittels Maximum-Likelihood-Methode vorgenommen und die Genauigkeit des Resultats anschlieĂend visuell und statistisch ausgewertet. Die Ergebnisse zeigen eindeutige Grenzen der Klassifizierung hochauflösender Bilddaten durch Einzelpixelverfahren auf. Dies wird im Hinblick auf potentielle LösungsvorschlĂ€ge diskutiert. Basierend auf dem Zwischenergebnis wird unter Einbeziehung zusĂ€tzlicher Geodaten und visueller Interpretation eine Ăberarbeitung der Daten vorgenommen. Das Ergebnis stellt die bislang hochauflösendste flĂ€chenhafte Vegetationskartierung fĂŒr den Nationalpark Asinara dar.Using remote sensing techniques and digital image analysis we conducted a digital mapping of vegetation types on the Mediterranean island of Asinara (Sardinia). Based on field data and high resolution satellite pictures (PlĂ©iades, 2 x 2 m) a pixel-based Supervised Classification via Maximum-Likelihood-Algorithm was realised and statistically as well as visually evaluated. The results show clear limits of pixel-based classifications with high resolution data. Editing these interim results by integrating auxiliary geodata together with visual interpretation of orthophotos we accomplished the first extensive high resolution mapping of vegetation types on Asinara
Improving engineering change management by introducing a standardised description for engineering changes for the automotive wiring harness
Engineering change management is a key part in the development of products that requires a lot of resources and time. A key problem is the lack of a shared ontology to describe engineering changes. This creates problems, additional effort and hinders the digitalisation of the engineering change management. This is especially true for the development of the automotive wiring harness where a low degree of automation together with the occurrence of many changes in a multi-variant system poses a big challenge. A description that is unambiguous, comprehensive and coherent is needed. The research presented in this paper tackles this problem. A standardised description for the engineering change management for the automotive wiring harness is introduced in this publication. The authors outline the approach that has been used to create a systematic description. The validation of the standardised description is based on two approaches: a case study of a development project and an ongoing development project. The validation shows that 94% of all engineering changes can be described in the proposed standardised way. Concepts where the standardised descriptions can be used to improve the engineering change process are outlined at the end of the paper. The paper thereby presents a way that directly improves the engineering change process and the product development process. It enables the further improvement of the engineering change management by providing a basis for an automatic processing, evaluation and implementation of engineering changes
Regulation of benthic oxygen fluxes in permeable sediments of the coastal ocean
Large areas of the oceanic shelf are composed of sandy sediments through which reactive solutes are transported via porewater advection fueling active microbial communities. The advective oxygen transport in permeable sands of the North Sea was investigated under in situ conditions using a new benthic observatory to assess the dynamic interaction of hydrodynamics, sediment morphodynamics, and oxygen penetration depth. During 16 deployments, concurrent measurement of current velocity, sediment topography, and porewater oxygen concentration were carried out. In all cases the oxyclines were found at depths of 1â6 cm, correlating with the topography of stationary and migrating bedforms (ripples). Different conditions in terms of bottom water currents and bedform migration led to fluctuating oxygen penetration depths and, hence, highly variable redox conditions in up to 2.5 cm thick layers beneath the surface. Volumetric oxygen consumption rates of surface sediments were measured on board in flow-through reactors. Bedform migration was found to reduce consumption rates by up to 50%, presumably caused by the washout of organic carbon that is otherwise trapped in the pore space of the sediment. Based on the observations we found oxygen penetration depths to be largely controlled by oxygen consumption rates, grain size, and current velocity. These controlling variables are summarized by an adapted Damköhler number which allows for prediction of oxygen penetretion depths based on a simple scaling law. By integrating the oxygen consumption rates over the oxygen penetration depth, oxygen fluxes of 8â34 mmol mâ2 dâ1 were estimate
NAC transcription factors ANAC087 and ANAC046 control distinct aspects of programmed cell death in the Arabidopsis columella and lateral root cap
Programmed cell death in plants occurs both during stress responses and as an integral part of regular plant development. Despite the undisputed importance of developmentally controlled cell death processes for plant growth and reproduction, we are only beginning to understand the underlying molecular genetic regulation. Exploiting the Arabidopsis thaliana root cap as a cell death model system, we identified two NAC transcription factors, the little-characterized ANAC087 and the leaf-senescence regulator ANAC046, as being sufficient to activate the expression of cell death-associated genes and to induce ectopic programmed cell death. In the root cap, these transcription factors are involved in the regulation of distinct aspects of programmed cell death. ANAC087 orchestrates postmortem chromatin degradation in the lateral root cap via the nuclease BFN1. In addition, both ANAC087 and ANAC046 redundantly control the onset of cell death execution in the columella root cap during and after its shedding from the root tip. Besides identifying two regulators of developmental programmed cell death, our analyses reveal the existence of an actively controlled cell death program in Arabidopsis columella root cap cells
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Leaf water ÎŽ18O reflects water vapour exchange and uptake by C3 and CAM epiphytic bromeliads in Panama.
The distributions of CAM and C3 epiphytic bromeliads across an altitudinal gradient in western Panama were identified from carbon isotope (ÎŽ13C) signals, and epiphyte water balance was investigated via oxygen isotopes (ÎŽ18O) across wet and dry seasons. There were significant seasonal differences in leaf water (ÎŽ18Olw), precipitation, stored 'tank' water and water vapour. Values of ÎŽ18Olw were evaporatively enriched at low altitude in the dry season for the C3 epiphytes, associated with low relative humidity (RH) during the day. Crassulacean acid metabolism (CAM) ÎŽ18Olw values were relatively depleted, consistent with water vapour uptake during gas exchange under high RH at night. At high altitude, cloudforest locations, C3 ÎŽ18Olw also reflected water vapour uptake by day. A mesocosm experiment with Tillandsia fasciculata (CAM) and Werauhia sanguinolenta (C3) was combined with simulations using a non-steady-state oxygen isotope leaf water model. For both C3 and CAM bromeliads, ÎŽ18Olw became progressively depleted under saturating water vapour by day and night, although evaporative enrichment was restored in the C3 W. sanguinolenta under low humidity by day. Source water in the overlapping leaf base 'tank' was also modified by evaporative ÎŽ18O exchanges. The results demonstrate how stable isotopes in leaf water provide insights for atmospheric water vapour exchanges for both C3 and CAM systems
The influence of the COVID-19 pandemic on surgical therapy and care: a cross-sectional study
Background: Due to the COVID-19 pandemic, an extensive reorganisation of healthcare resources was necessary-with a particular impact on surgical care across all disciplines. However, the direct and indirect consequences of this redistribution of resources on surgical therapy and care are largely unknown.
Methods: We analysed our prospectively collected standardised digital quality management document for all surgical cases in 2020 and compared them to the years 2018 and 2019. Periods with high COVID-19 burdens were compared with the reference periods in 2018 and 2019.
Results: From 2018 to 2020, 10,723 patients underwent surgical treatment at our centres. We observed a decrease in treated patients and a change in the overall patient health status. Patient age and length of hospital stay increased during the COVID-19 pandemic (p = 0.004 and p = 0.002). Furthermore, the distribution of indications for surgical treatment changed in favour of oncological cases and less elective cases such as hernia repairs (p < 0.001). Postoperative thromboembolic and pulmonary complications increased slightly during the COVID-19 pandemic. There were slight differences for postoperative overall complications according to Clavien-Dindo, with a significant increase of postoperative mortality (p = 0.01).
Conclusion: During the COVID-19 pandemic we did not see an increase in the occurrence, or the severity of postoperative complications. Despite a slightly higher rate of mortality and specific complications being more prevalent, the biggest change was in indication for surgery, resulting in a higher proportion of older and sicker patients with corresponding comorbidities. Further research is warranted to analyse how this changed demographic will influence long-term patient care
The impact of bedform migration on benthic oxygen fluxes
Permeable sediments are found wide spread in river beds and on continental shelves. The transport of these sediments is forced by bottom water currents and leads to the formation of bedforms such as ripples and dunes. The bottom water flow across the bedforms results in pressure gradients that drive pore water flow within the permeable sediment and enhance the supply of reactive substrates for biogeochemical processes. This transport-reaction system has been extensively studied for the case of stationary bedforms, whereas bedform migrationâthe most ubiquitous form of sediment transportâhas been often ignored. To study the impact of sediment transport on pore water flow, we incorporated an empirical model of bedform migration into a numerical transport-reaction model for porous media, using oxygen as reactive solute. The modeled oxygen flux changes significantly as soon as the sediment divides into an upper mobile layer (migrating bedform) and a stationary layer underneath. The bedform is increasingly flushed with oxic bottom water, whereas pressure gradients and pore water flow reverse at increasing rate underneath the bedform. This suppresses net pore water displacement and reduces the oxygen penetration depth up to 90%. In effect, the overall oxygen uptake decreases significantly with bedform migration although bottom water velocities increase. This counterintuitive effect is systematically described for a range of different sediment types, current velocities, and respiration rates and should be considered in future studies
Abiotic and Biotic Soil Characteristics in Old Growth Forests and Thinned or Unthinned Mature Stands in Three Regions of Oregon
We compared forest floor depth, soil organic matter, soil moisture, anaerobic mineralizable nitrogen (a measure of microbial biomass), denitrification potential, and soil/litter arthropod communities among old growth, unthinned mature stands, and thinned mature stands at nine sites (each with all three stand types) distributed among three regions of Oregon. Mineral soil measurements were restricted to the top 10 cm. Data were analyzed with both multivariate and univariate analyses of variance. Multivariate analyses were conducted with and without soil mesofauna or forest floor mesofauna, as data for those taxa were not collected on some sites. In multivariate analysis with soil mesofauna, the model giving the strongest separation among stand types (P = 0.019) included abundance and richness of soil mesofauna and anaerobic mineralizable nitrogen. The best model with forest floor mesofauna (P = 0.010) included anaerobic mineralizable nitrogen, soil moisture content, and richness of forest floor mesofauna. Old growth had the highest mean values for all variables, and in both models differed significantly from mature stands, while the latter did not differ. Old growth also averaged higher percent soil organic matter, and analysis including that variable was significant but not as strong as without it. Results of the multivariate analyses were mostly supported by univariate analyses, but there were some differences. In univariate analysis, the difference in percent soil organic matter between old growth and thinned mature was due to a single site in which the old growth had exceptionally high soil organic matter; without that site, percent soil organic matter did not differ between old growth and thinned mature, and a multivariate model containing soil organic matter was not statistically significant. In univariate analyses soil mesofauna had to be compared nonparametrically (because of heavy left-tails) and differed only in the Siskiyou Mountains, where they were most abundant and species rich in old growth forests. Species richness of mineral soil mesofauna correlated significantly (+) with percent soil organic matter and soil moisture, while richness of forest floor mesofauna correlated (+) with depth of the forest floor. Composition of forest floor and soil mesofauna suggest the two groups represent a single community. Soil moisture correlated highly with percent soil organic matter, with no evidence for drying in sites that were sampled relatively late in the summer drought, suggesting losses of surface soil moisture were at least partially replaced by hydraulic lift (which has been demonstrated in other forests of the region)
Robotic versus open pancreatic surgery: a propensity score-matched cost-effectiveness analysis
Background: Robotic pancreatic surgery (RPS) is associated with high intraoperative costs compared to open pancreatic surgery (OPS). However, it remains unclear whether several advantages of RPS such as reduced surgical trauma and a shorter postoperative recovery time could lead to a reduction in total costs outweighing the intraoperative costs. The study aimed to compare patients undergoing OPS and RPS with regards to cost-effectiveness in a propensity score-matched (PSM) analysis.
Methods: Patients undergoing OPS and RPS between 2017 and 2019 were included in this monocentric, retrospective analysis. The controlling department provided financial data (costs and revenues, net loss/profit). A propensity score-matched analysis was performed or OPS and RPS (matching criteria: age, American society of anesthesiologists (ASA) score, gender, body mass index (BMI), and type of pancreatic resection) with a caliper 0.2.
Results: In total, 272 eligible OPS cases were identified, of which 252 met all inclusion criteria and were thus included in the further analysis. The RPS group contained 92 patients. The matched cohorts contained 41 patients in each group. Length of hospital stay (LOS) was significantly shorter in the RPS group (12 vs. 19 days, p = 0.003). Major postoperative morbidity (Dindo/Clavien >= 3a) and 90-day mortality did not differ significantly between OPS and RPS (p > 0.05). Intraoperative costs were significantly higher in the RPS group than in the OPS group (7334euro vs. 5115euro, p revenue).
Conclusions: Surgical outcomes of RPS were similar to those of OPS. Higher intraoperative costs of RPS are outweighed by advantages in other categories of cost-effectiveness such as decreased lengths of hospital stay
KIRA1 and ORESARA1 terminate flower receptivity by promoting cell death in the stigma of Arabidopsis
Flowers have a species-specific functional life span that determines the time window in which pollination, fertilization and seed set can occur. The stigma tissue plays a key role in flower receptivity by intercepting pollen and initiating pollen tube growth toward the ovary. In this article, we show that a developmentally controlled cell death programme terminates the functional life span of stigma cells in Arabidopsis. We identified the leaf senescence regulator ORESARA1 (also known as ANAC092) and the previously uncharacterized KIRA1 (also known as ANAC074) as partially redundant transcription factors that modulate stigma longevity by controlling the expression of programmed cell death-associated genes. KIRA1 expression is sufficient to induce cell death and terminate floral receptivity, whereas lack of both KIRA1 and ORESARA1 substantially increases stigma life span. Surprisingly, the extension of stigma longevity is accompanied by only a moderate extension of flower receptivity, suggesting that additional processes participate in the control of the flower's receptive life span
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