The Open Global Glacier Model (OGGM) v1.1 Maussion, Fabien; Butenko, Anton; Champollion, Nicolas ...
Geoscientific Model Development,
03/2019, Letnik:
12, Številka:
3
Journal Article
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Despite their importance for sea-level rise, seasonal water availability, and
as a source of geohazards, mountain glaciers are one of the few remaining
subsystems of the global climate system for ...which no globally applicable,
open source, community-driven model exists. Here we present the Open Global
Glacier Model (OGGM), developed to provide a modular and open-source
numerical model framework for simulating past and future change of any
glacier in the world. The modeling chain comprises data downloading tools
(glacier outlines, topography, climate, validation data), a preprocessing
module, a mass-balance model, a distributed ice thickness estimation model,
and an ice-flow model. The monthly mass balance is obtained from gridded
climate data and a temperature index melt model. To our knowledge, OGGM is
the first global model to explicitly simulate glacier dynamics: the model
relies on the shallow-ice approximation to compute the depth-integrated flux
of ice along multiple connected flow lines. In this paper, we describe and
illustrate each processing step by applying the model to a selection of
glaciers before running global simulations under idealized climate forcings.
Even without an in-depth calibration, the model shows very realistic
behavior. We are able to reproduce earlier estimates of global glacier volume
by varying the ice dynamical parameters within a range of plausible values.
At the same time, the increased complexity of OGGM compared to other
prevalent global glacier models comes at a reasonable computational cost:
several dozen glaciers can be simulated on a personal computer, whereas
global simulations realized in a supercomputing environment take up to a few
hours per century. Thanks to the modular framework, modules of various
complexity can be added to the code base, which allows for new kinds of model
intercomparison studies in a controlled environment. Future developments will
add new physical processes to the model as well as automated calibration
tools. Extensions or alternative parameterizations can be easily added by the
community thanks to comprehensive documentation. OGGM spans a wide range of
applications, from ice–climate interaction studies at millennial timescales
to estimates of the contribution of glaciers to past and future sea-level
change. It has the potential to become a self-sustained community-driven
model for global and regional glacier evolution.
Aim. Evaluation of the possible advantages of measuring blood pressure (BP) with a professional tonometer for in-line screening of blood pressure, pulse, ar-rhythmia (oscillometric method) in a ...hospital over measuring blood pressure using the auscultation method. Methods and outcomes. 2503 blood pressure measurements by the oscillometric method in 165 patients were analyzed. Of these, 136 people were ≥ 20–21 years old with a history of arterial hypertension – AH (1st group) and 29 people were young persons (18–20 years old) with no history of AH (2nd group). Results. Only 13,3% of participants had never measured BP; 24,1% of the 2nd group required antihypertensive therapy following the results of this study. The percentage of patients' awareness of their BP levels among those who measured BP by the auscultation method and by the oscillometric method was 10 and 100%, correspondently. In the course of the study, heart rhythm alterations were revealed in 9,5% of patients when using the oscillometric method. The measurement of BP in all patients in the department by one desk nurse requires 2 times less time when using the oscillometric method compared to the auscultation method. Conclusions. When measuring BP by the oscillometric method, regardless of patients’ age and gender, their awareness of the level of AH increases. Given a modern character of measurement and submitting data to the medical records in inpatients patients for accurate and quick correction of AH, detection of cardiac arrhythmias, it is preferable to choose a professional tonometer based on the oscillometric method for in-line specification of BP, pulse, arrhythmia. With regular BP monitoring, there is a correction of behavioral risk factors and adherence to antihypertensive therapy are corrected.
Fire spotting is often responsible for dangerous flare-ups in wildfires and causes secondary ignitions isolated from the primary fire zone, which lead to perilous situations. The main aim of the ...present research is to provide a versatile probabilistic model for fire spotting that is suitable for implementation as a post-processing scheme at each time step in any of the existing operational large-scale wildfire propagation models, without calling for any major changes in the original framework. In particular, a complete physical parameterisation of fire spotting is presented and the corresponding updated model RandomFront 2.3 is implemented in a coupled fire–atmosphere model: WRF-SFIRE. A test case is simulated and discussed. Moreover, the results from different simulations with a simple model based on the level set method, namely LSFire+, highlight the response of the parameterisation to varying fire intensities, wind conditions and different firebrand radii. The contribution of the firebrands to increasing the fire perimeter varies according to different concurrent conditions, and the simulations show results in agreement with the physical processes. Among the many rigorous approaches available in the literature to model firebrand transport and distribution, the approach presented here proves to be simple yet versatile for application to operational large-scale fire spread models.
A Lorenz curve is a graphical representation of the distribution of income or wealth within a population. The generalized Lorenz curve can be created by scaling the values on the vertical axis of a ...Lorenz curve by the average output of the distribution. In this paper, we propose two non-parametric methods for testing the equality of two generalized Lorenz curves. Both methods are based on empirical likelihood and utilize a U-statistic. We derive the limiting distribution of the likelihood ratio, which is shown to follow a chi-squared distribution with one degree of freedom. We performed simulations to evaluate how well the proposed methods perform compared to an existing method, by examining their Type I error rates and power across different sample sizes and distribution assumptions. Our results show that the proposed methods exhibit superior performance in finite samples, particularly in small sample sizes, and are robust across various scenarios. Finally, we use real-world data to illustrate the methods of testing two generalized Lorenz curves.
The Open Global Glacier Model (Author abstract) Maussion, Fabien; Butenko, Anton; Champollion, Nicolas ...
Geoscientific model development,
03/2019, Letnik:
12, Številka:
3
Journal Article
This research work attempts to reveal the mechanism of alkali corrosion in cement composites in the presence of plasticizers based on polycarboxylates (PCE), naphtha-lene-formaldehydes (SPNF), and ...lignosulfonates by maintaining a high pH of the liquid phase and additionally containing monovalent alkali earth metals in cement stone, as well as stopping this process by introducing an active mineral additive. ASR is studied by changing the relative strain with time according to ASTM C-1260. Deformation changes were confirmed by SEM and RFA studies of hydration products and ASR in the microstructure. Separate use of PCE plasticizers in the cement composition increases deformation by 50% to the 56th day; the use of SPNF increases deformation by 10% compared with the additive-free composition. The use of PLS reduces the relative deformation by 25%. The introduction of silica fume into cementitious composites containing plasticizers actually stops ASR only for a short time. A reduction in deformation during MC use together with plasticizer based on naphthalene sulfonate and polycarboxylate occurs only when the dosage of MS is increased to 20–30%; at a lower dosage, the effect is negative, which also affects the phase composition of the composites. The introduction of MC increases the value of the relative deformation compared with plasticizer compositions based only on PLS. SEM studies have detected microcracks and dense fine-crystalline silicate gel, which cause deformation changes in cement composite samples. Research has shown that concrete modified with SPNF and PCE at the maximum dosage of MC (30%) has minimal deformation rates and can be used to select optimal concrete compositions. The results of this study could help to minimize risks, prevent unacceptable expansion, and ensure the high quality of concrete and concrete products during their use as part of various nature-modifying additives.
The phylum Euglenozoa is a group of flagellated protists comprising the diplonemids, euglenids, symbiontids, and kinetoplastids. The diplonemids are highly abundant and speciose, and recent tools ...have rendered the best studied representative, Diplonema papillatum, genetically tractable. However, despite the high diversity of diplonemids, their lifestyles, ecological functions, and even primary energy source are mostly unknown.
We designed a metabolic map of D. papillatum cellular bioenergetic pathways based on the alterations of transcriptomic, proteomic, and metabolomic profiles obtained from cells grown under different conditions. Comparative analysis in the nutrient-rich and nutrient-poor media, as well as the absence and presence of oxygen, revealed its capacity for extensive metabolic reprogramming that occurs predominantly on the proteomic rather than the transcriptomic level. D. papillatum is equipped with fundamental metabolic routes such as glycolysis, gluconeogenesis, TCA cycle, pentose phosphate pathway, respiratory complexes, β-oxidation, and synthesis of fatty acids. Gluconeogenesis is uniquely dominant over glycolysis under all surveyed conditions, while the TCA cycle represents an eclectic combination of standard and unusual enzymes.
The identification of conventional anaerobic enzymes reflects the ability of this protist to survive in low-oxygen environments. Furthermore, its metabolism quickly reacts to restricted carbon availability, suggesting a high metabolic flexibility of diplonemids, which is further reflected in cell morphology and motility, correlating well with their extreme ecological valence.
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