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216 result(s) for "V. Geiger"
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Irrigation characterization improved by the direct use of SMAP soil moisture anomalies within a data assimilation system
Prior soil moisture data assimilation (DA) efforts to incorporate human management features such as agricultural irrigation has only shown limited success. This is partly due to the fact that observational rescaling approaches for bias correction used in soil moisture DA systems are less effective when unmodeled processes such as irrigation are the dominant source of systematic biases. In this article, we demonstrate an alternative approach, i.e. anomaly correction for overcoming this limitation. Unlike the rescaling approaches, the proposed method does not scale remote sensing soil moisture retrievals to the model climatology, but it extracts the temporal variability information from the retrievals. The study demonstrates this approach through the assimilation of soil moisture retrievals from the Soil Moisture Active Passive mission into the Noah land surface model. The results demonstrate that DA using the anomaly correction method can better capture the effect of irrigation on soil moisture in agricultural areas while providing comparable performance to the DA integrations using rescaling approaches in non-irrigated areas. These findings emphasize the need to reduce inconsistencies between remote sensing and the models so that assimilation methods can employ information from remote sensing more directly to develop representations of unmodeled processes such as irrigation.
The Land surface Data Toolkit (LDT v7.2) – a data fusion environment for land data assimilation systems
The effective applications of land surface models (LSMs) and hydrologic models pose a varied set of data input and processing needs, ranging from ensuring consistency checks to more derived data processing and analytics. This article describes the development of the Land surface Data Toolkit (LDT), which is an integrated framework designed specifically for processing input data to execute LSMs and hydrological models. LDT not only serves as a preprocessor to the NASA Land Information System (LIS), which is an integrated framework designed for multi-model LSM simulations and data assimilation (DA) integrations, but also as a land-surface-based observation and DA input processor. It offers a variety of user options and inputs to processing datasets for use within LIS and stand-alone models. The LDT design facilitates the use of common data formats and conventions. LDT is also capable of processing LSM initial conditions and meteorological boundary conditions and ensuring data quality for inputs to LSMs and DA routines. The machine learning layer in LDT facilitates the use of modern data science algorithms for developing data-driven predictive models. Through the use of an object-oriented framework design, LDT provides extensible features for the continued development of support for different types of observational datasets and data analytics algorithms to aid land surface modeling and data assimilation.
A NASA–Air Force Precipitation Analysis for Near-Real-Time Operations
This article describes a new precipitation analysis algorithm developed by NASA for time-sensitive operations at the United States Air Force. Implemented as part of the Land Information System}a land modeling and data assimilation software framework}this NASA–Air Force Precipitation Analysis (NAFPA) combines numerical weather prediction model outputs with rain gauge measurements and satellite estimates to produce global, gridded 3-h accumulated precipitation fields at approximately 10-km resolution. Input observations are subjected to quality control checks before being used by the Bratseth analysis algorithm that converges to optimal interpolation. NAFPA assimilates up to 3.5 million observations without artificial data thinning or selection. To evaluate this new approach, a multiyear reanalysis is generated and intercompared with eight alternative precipitation products across the contiguous United States, Africa, and the monsoon region of eastern Asia. NAFPA yields superior accuracy and correlation over low-latency (up to 14 h) alternatives (numerical weather prediction and satellite retrievals), and often outperforms high-latency (up to 3.5 months) products, although the details for the latter vary by region and product. The development of NAFPA offers a high-quality, near-real-time product for use in meteorological, land surface, and hydrological research and applications.
Evaluating Clouds in Long-Term Cloud-Resolving Model Simulations with Observational Data
Two 20-day, continental midlatitude cases are simulated with a three-dimensional (3D) cloud-resolving model (CRM) and are compared to Atmospheric Radiation Measurement Program (ARM) data. Surface fluxes from ARM ground stations and a land data assimilation system are used to drive the CRM. This modeling evaluation shows that the model simulates precipitation well but overpredicts clouds, especially in the upper troposphere. The evaluation also shows that the ARM surface fluxes can have noticeable errors in summertime. Theoretical analysis reveals that buoyancy damping is sensitive to spatial smoothers in two-dimensional (2D) CRMs, but not in 3D ones. With this theoretical analysis and the ARM cloud observations as background, 2D and 3D simulations are compared, showing that the 2D CRM has not only rapid fluctuations in surface precipitation but also spurious dehumidification (or a decrease in cloud amount). The present study suggests that the rapid precipitation fluctuation and spurious dehumidification be attributed to the sensitivity of buoyancy damping to dimensionality.
Outcome after operative treatment of Vancouver type B1 and C periprosthetic femoral fractures: open reduction and internal fixation versus revision arthroplasty
IntroductionThe rate of periprosthetic femoral fractures after hip arthroplasty is rising and the estimated current lifetime incidence is 0.4–2.1%. While most authors recommend revision arthroplasty in patients with loose femoral shaft components, treatment options for patients with stable stem are not fully elucidated.MethodAgainst this background we performed a retrospective chart analysis with clinical follow-up examination of 32 cases that sustained a Vancouver type B1 or C periprosthetic fracture (stable stem).PatientsOverall 16 cases were treated by open reduction and internal fixation (ORIF) by plate osteosynthesis and 16 cases by revision arthroplasty (RA). Both groups were comparable regarding age, gender, follow-up time interval, time interval from primary hip arthroplasty to fracture and rate of cemented femoral components, but more type C fractures were treated by ORIF.ResultsFunctional outcome expressed by the median timed “Up and Go” test did not differ significantly (30 s ORIF vs. 24 s RA, P = 0.19). However, by comparable systemic complications surgery-related complications were significantly more frequent in plate osteosynthesis (ORIF n = 10 vs. RA n = 3, P = 0.03). Based on our results, further studies, preferable via a multicenter approach, should focus on identifying patients that benefit from ORIF in periprosthetic fractures. A misinterpretation of type B2 fractures with loose implant as type B1 fractures may cause implant failure in case of ORIF.ConclusionThe use of angular stable implants, additional cable wires or bone enhancing means is recommended.
Predictors of pulmonary failure following severe trauma: a trauma registry-based analysis
Background The incidence of pulmonary failure in trauma patients is considered to be influenced by several factors such as liver injury. We intended to assess the association of various potential predictors of pulmonary failure following thoracic trauma and liver injury. Methods Records of 12,585 trauma patients documented in the TraumaRegister DGU ® of the German Trauma Society were analyzed regarding the potential impact of concomitant liver injury on the incidence of pulmonary failure using uni- and multivariate analyses. Pulmonary failure was defined as pulmonary failure of ≥ 3 SOFA-score points for at least two days. Patients were subdivided according to their injury pattern into four groups: group 1: AIS thorax < 3; AIS liver < 3; group 2: AIS thorax ≥ 3; AIS liver < 3; group 3: AIS thorax < 3; AIS liver ≥ 3 and group 4: AIS thorax ≥ 3; AIS liver ≥ 3. Results Overall, 2643 (21%) developed pulmonary failure, 12% (n= 642) in group 1, 26% (n= 697) in group 2, 16% (n= 30) in group 3, and 36% (n= 188) in group 4. Factors independently associated with pulmonary failure included relevant lung injury, pre-existing medical conditions (PMC), sex, transfusion of more than 10 units of packed red blood cells (PRBC), Glasgow Coma Scale (GCS) ≤ 8, and the ISS. However, liver injury was not associated with an increased risk of pulmonary failure following severe trauma in our setting. Conclusions Specific factors, but not liver injury, were associated with an increased risk of pulmonary failure following trauma. Trauma surgeons should be aware of these factors for optimized intensive care treatment.
Periprosthetic humeral fractures after shoulder arthroplasty: operative management and functional outcome
BackgroundCurrently, little information is available on functional outcome of periprosthetic humeral fractures after shoulder arthroplasty. This investigation aimed to evaluate functional and radiological outcome and patients’ satisfaction following this type of injury treated by open reduction and internal fixation.MethodsRetrospective chart analysis of patients treated at two level-I trauma centers. Patients were examined clinically and radiologically. Additionally, functional outcome was assessed using the established DASH-questionnaire and standardized examination for calculation of the Constant score.ResultsFive out of six patients showed complete fracture consolidation with satisfying functional results (mean follow up time 62 weeks). One patient showed major complications with poor outcome. DASH and Constant scores were comparable to those described after primary shoulder arthroplasty.ConclusionsPeriprosthetic humeral fractures after shoulder arthroplasty can be treated by angular stable plating with low complication rates and acceptable results.
Role of lung contusions on posttraumatic inflammatory response and organ dysfunction in traumatized patients
Background: Multiple trauma is often accompanied by lung contusion leading to secondary pulmonary inflammation and organ dysfunction. The particular role of lung contusions on the systemic inflammatory response remains unclear. Therefore, the aim of the present study was to compare the degree of lung contusion with markers of inflammation and multiple organ failure (MOF) in trauma patients. Methods: According to the Injury Severity Score (ISS), 45 patients were assigned to a low (< 25 points) and a high ISS group (> 25 points), respectively. Both groups were subdivided into minor and major lung injury groups as defined by computed tomography (CT) scan. Plasma levels of interleukin 6 (IL-6), interleukin 8 (IL-8), tumor necrosis factor (TNF) receptors, C-reactive protein (CRP), and polymorphonuclear (PMN) elastase were assessed, as well as the Murray lung score (MLS) and the MOF score. Results: Patients with low ISS present moderate activation of inflammation which is not influenced by the degree of lung contusion. In contrast, patients with a high ISS develop significant posttraumatic inflammation and MOF. Patients with high ISS and severe lung contusions present significantly higher MLS and MOF scores. Interestingly, patients of the high ISS group without severe lung contusions develop a similar degree of MLS and MOF only after 5 days following the traumatic insult. However, the initial plasma levels of IL-6 and IL-8 differ significantly in this group. Conclusion: Our data show that severe lung contusions contributes to an immediate onset of posttraumatic inflammation in severely traumatized patients, resulting in MOF, while in severely injured patients without lung contusion, this development requires up to 5 days.
Reshaping teacher and student roles in technology-enriched classrooms
This paper draws on data from a three-year longitudinal study of secondary school classrooms to examine pedagogical issues in using technology resources in mathematics teaching-in particular, graphics calculators and overhead projection panels that allow screen output to be viewed by the whole class. We theorise four roles for technology in relation to such teaching and learning interactions- master, servant, partner, and extension of self-and illustrate this taxonomy with observational data from five senior secondary mathematics classrooms. Our research shows how technology can facilitate collaborative inquiry during both small group interactions and whole class discussions when students use their calculators and the overhead projection panel to share their mathematical understanding. [Author abstract]
Frühzeitige Diagnose erspart Gelenkersatz
SummaryPigmented villonodular synovitis (PVNS) is a rare, strongly proliferative disease of the lining of the joint, synovial bursa and tendon (synovial) sheath. If left untreated, it leads to severe destruction of the joint resulting in an early need for endoprosthetic replacement. The clinical signs are unspecific. Using the diagnostic gold standard MRI, the complete extent of PVNS can usually be determined non-invasively. Once histological confirmation has been obtained, radical tumor resection, synovectomy, possibly curettage, and postoperative irradiation must be applied.