Modelling Of Region Research Articles

Sources and nature of ice-nucleating particles in the free troposphere at Jungfraujoch in winter 2017

Abstract. Primary ice formation in mixed-phase clouds is initiated by a minute subset of the ambient aerosol population, called ice-nucleating particles (INPs). The knowledge about their atmospheric concentration, composition, and source in cloud-relevant environments is still limited. During the 2017 joint INUIT/CLACE (Ice Nuclei research UnIT/CLoud–Aerosol Characterization Experiment) field campaign, observations of INPs as well as of aerosol physical and chemical properties were performed, complemented by source region modeling. This aimed at investigating the nature and sources of INPs. The campaign took place at the High-Altitude Research Station Jungfraujoch (JFJ), a location where mixed-phase clouds frequently occur. Due to its altitude of 3580 m a.s.l., the station is usually located in the lower free troposphere, but it can also receive air masses from terrestrial and marine sources via long-range transport. INP concentrations were quasi-continuously detected with the Horizontal Ice Nucleation Chamber (HINC) under conditions representing the formation of mixed-phase clouds at −31 ∘C. The INP measurements were performed in parallel to aerosol measurements from two single-particle mass spectrometers, the Aircraft-based Laser ABlation Aerosol MAss Spectrometer (ALABAMA) and the laser ablation aerosol particle time-of-flight mass spectrometer (LAAPTOF). The chemical identity of INPs is inferred by correlating the time series of ion signals measured by the mass spectrometers with the time series of INP measurements. Moreover, our results are complemented by the direct analysis of ice particle residuals (IPRs) by using an ice-selective inlet (Ice-CVI) coupled with the ALABAMA. Mineral dust particles and aged sea spray particles showed the highest correlations with the INP time series. Their role as INPs is further supported by source emission sensitivity analysis using atmospheric transport modeling, which confirmed that air masses were advected from the Sahara and marine environments during times of elevated INP concentrations and ice-active surface site densities. Indeed, the IPR analysis showed that, by number, mineral dust particles dominated the IPR composition (∼58 %), and biological and metallic particles are also found to a smaller extent (∼10 % each). Sea spray particles are also found as IPRs (17 %), and their fraction in the IPRs strongly varied according to the increased presence of small IPRs, which is likely due to an impact from secondary ice crystal formation. This study shows the capability of combining INP concentration measurements with chemical characterization of aerosol particles using single-particle mass spectrometry, source region modeling, and analysis of ice residuals in an environment directly relevant for mixed-phase cloud formation.

Regionalization of congenital cardiac surgical care: what it will take.

Decentralized, inconsistent healthcare delivery results in variable outcomes and wastes nearly one trillion dollars annually in the United States (US). Congenital heart surgery (CHS) is not immune due to high, variable costs and inconsistent outcomes across hospitals. Many European countries and Canada have addressed these issues by regionalizing CHS. Centralizing resources lowers costs, reduces in-hospital mortality and improves long-term survival. Although the impact on travel distance for patients is limited, the effect on healthcare disparities requires study. This review summarizes current data and integrates these into paths to regionalization through health policy, research, and academic collaboration. There are too many CHS programs in the US with unnecessarily high densities of centers in certain regions. This distribution lowers center and surgeon case volumes, creates redundancy, and increases variation in costs and outcomes. Simultaneously, adhering to suboptimal allocation impedes the understanding of optimal regionalization models to optimize congenital cardiac care delivery. CHS regionalization models developed for the US increase surgeon and center volume, decrease healthcare spending, and improve patient outcomes without substantially increasing travel distance. Regionalization in countries with few or no existing CHS programs is yet to be explored, but may be associated with more efficient spending and procedural complexity expansion.

Breaking the Degeneracy in Magnetic Cataclysmic Variable X-Ray Spectral Modeling Using X-Ray Light Curves

Abstract We present an analysis of mock X-ray spectra and light curves of magnetic cataclysmic variables using an upgraded version of the 3D cyclops code. This 3D representation of the accretion flow allows us to properly model total and partial occultation of the postshock region by the white dwarf as well as the modulation of the X-ray light curves due to the phase-dependent extinction of the preshock region. We carried out detailed postshock region modeling in a four-dimensional parameter space by varying the white dwarf mass and magnetic field strength as well as the magnetosphere radius and the specific accretion rate. To calculate the postshock region temperature and density profiles, we assumed equipartition between ions and electrons; took into account the white dwarf gravitational potential, the finite size of the magnetosphere, and a dipole-like magnetic field geometry; and considered cooling by both bremsstrahlung and cyclotron radiative processes. By investigating the impact of the parameters on the resulting X-ray continuum spectra, we show that there is an inevitable degeneracy in the four-dimensional parameter space investigated here, which compromises X-ray continuum spectral fitting strategies and can lead to incorrect parameter estimates. However, the inclusion of X-ray light curves in different energy ranges can break this degeneracy, and it therefore remains, in principle, possible to use X-ray data to derive fundamental parameters of magnetic cataclysmic variables, which represents an essential step toward understanding their formation and evolution.

MODELING TOURISTS’ SATISFACTION IN THE NATURE-BASED TOURIST DESTINATION USING STRUCTURAL EQUATION MODELING TECHNIQUE

The goal of this study is to show how satisfied tourists is of supreme significance to the tourism industry, particularly as it affects the future of a nature-based destination and explores the relationship among destination image, service quality, perceived value, tourist satisfaction, word-of-mouth, and revisit intentions of tourists. The 292 survey data was obtained via a structured questionnaire from tourists who visited the Haor region, Bangladesh and structural equation modeling (SEM) is used to test the hypothetical paths. Six hypotheses were accepted, and one is rejected. Tourism stakeholders can find important knowledge and they can satisfy tourists, which is likely by improving destination.

Use of gridded climate data for hydrological modelling in the Zambezi River Basin, Southern Africa

The Zambezi River Basin is among many basins in Southern African region with inadequate, low resolution, poorly maintained and distributed network of hydrometeorological stations. This scenario entails scarcity of hydrological data in the basin and subsequently leads to poor assessment of water resources. This paper investigates alternative technologies in the assessment of the hydrology and water resources in the basin. The high-resolution gridded climate data together with land use and soil data were used as inputs into SWAT model to simulate hydrological processes. Calibration and validation of model were performed using SWAT-CUP. Comparison of average monthly rainfall data for gridded and observed shows 97% correlation. The statistics show NS to be 0.73 while R2 was 0.73. The uncertainty analysis was determined with a P-factor at 0.75 while the R-factor was 0.75. Therefore, use of gridded climate data for hydrological modelling in data scarce regions could be a useful tool to estimate the main hydrological parameters and water resources of an area with satisfactory accuracy.

Analysis of Enhanced Built-up and Bare Land Index (EBBI) in the Urban Area of Yangon, Myanmar

In planning and reviewing changes in the ground overview data, land distribution guidelines and identification of changes are critical. The availability of free global and historical satellite images offers a valuable resource for the built-up region to be continuously and accurately mapped and tracked year by year. For thirty years of data, this study uses Landsat images to obtain substantial and land spread data that is extremely useful for urban arrangement. This paper mainly focuses on the basic extraction of the built-up area for the urban planning area every five years from the satellite images of LANDSAT 5,7,8 and Sentinel 2A from USGS. The goal is to evaluate the year-by-year shift in the urban built-up area and to obtain the accuracy of the mapping of built-up and bare land areas in the study of the urban built-up trend from 1990 to 2020. In this research, GIS tools such as raster calculator and built-up region modeling are used to measure the indices that include the Enhanced Built-up and Bareness Index (EBBI), the Normalized Difference Built-up Index (NDBI) and the Urban Index (UI) or the Built-up Index (BUI). This study will therefore point out a variable approach to mapping traditional enhanced built-up and bare land changes (EBBI) automatically with simple indices and according to index outputs. The uncoordinated areas of land and population urbanization spread from areas and gradually the link between the expansion of urban land development and population growth has moved from weak positive to strong decoupling. The advantage of the method the enhanced built-up and bareness index (EBBI) can therefore be realized with the correlation of linear regression slightly expanded in 2020 over the last thirty years. The percentage of the outputs between the indexes and population rate was to use the entire spectral range of Landsat imageries which cause less spectral confusion between built-up area changes and higher accuracies compared to other indices. The modelling method was effective, quickly simple to implement, and can be used to find out the built-up area extraction.

Regionalización del caudal máximo anual en cuencas del sistema hidrográfico del río Colorado, Argentina

La predicción del caudal máximo anual resulta de utilidad para la gestión de eventos extremos relacionados con crecidas. Para realizar estimaciones con bajo grado de incertidumbre es necesario contar con una gran cantidad de información hidrométrica. Las cuencas que integran el sistema hidrográfico del río Colorado presentan una topografía que dificulta el mantenimiento de las estaciones hidrométricas, razón por la cual, se carece de continuidad en los registros y se presentan en varios casos sectores sin aforar. La regionalización consiste en la transferencia de información de los sitios aforados a los no aforados para la predicción de caudales. El objeto del trabajo fue encontrar la función que relaciona el caudal máximo anual con las características climáticas y morfométricas de las cuencas. Para ello, se emplearon modelos de regresión simple. A partir de dicha relación y la curva de frecuencia regional es posible predecir caudales máximos anuales para diferentes períodos de retorno en cuencas sin aforo pertenecientes al sistema hidrográfico del río Colorado, Argentina. De los doce modelos analizados, los mejores resultados se presentan cuando la variable predictora es el área y perímetro de la cuenca. Los errores de los modelos de regionalización para diversos sitios del sistema resultaron entre el 6% y el 67%. Estos modelos constituyen una herramienta para la gestión de crecidas en el centro oeste argentino.

Determination of burn severity models ranging from regional to national scales for the conterminous United States

Identifying meaningful measures of ecological change over large areas is dependent on the quantification of robust relationships between ecological metrics and remote sensing products. Over the past several decades, ground observations of wildfire and prescribed fire severity have been acquired across hundreds of wildland fires in the United States, primarily utilizing the Composite Burn Index (CBI) plot protocol. These observations have been coupled to spaceborne passive spectral reflectance indices (e.g. Landsat-derived variations of the Normalized Burn Ratio [NBR]) to produce regression models describing their relationship. Here we develop regression models by vegetation type for multiple vegetation classification systems representing a range of spatial scales, and a decision tree framework for evaluating these regression models. Our overall goals were to determine which scale of ecological classifications provided the best estimate of burn severity from Landsat data and how to choose the best regression model. We aggregated a total of 6280 CBI plots for 234 wildland fires that burned between 1994 and 2017 and produced Landsat-derived NBR and differenced NBR (dNBR) values for each plot. We then calculated best fit linear or higher order regression equations between CBI and NBR/dNBR for each landcover classification system from smallest to largest scale: LANDFIRE Biophysical Settings (BPS), National Vegetation Classification macrogroup (NVC) landcover classifications, Omernick III, II, and I ecoregions, LANDFIRE Fire Regime Groups (FRG), and the entire conterminous United States (CONUS) dataset. The CONUS regression model goodness of fit was moderate (R2 = 0.55, P < 0.001) for dNBR and poor (R2 = 0.30, P < 0.001) for NBR. Within landcover classifications, CBI was better fit by dNBR than NBR. Finer scale regional regression models including BPS (dNBR R2¯ = 0.56 and 0.00–0.83 R2 range; NBR R2¯ = 0.43 and 0.00–0.82 R2 range) and NVC (dNBR R2¯ = 0.55 and 0.15–0.78 R2 range; NBR R2¯ = 0.41 and 0.00–0.79 R2 range) were on average the same or better than the CONUS models for dNBR and NBR, with the strongest fit models exhibiting R2 ≥ 0.70, whereas larger scale regional models R2¯ ranged from 0.28 to 0.5. However, variation in accuracy among landcover types indicate that dNBR and NBR regression models could be used to effectively estimate CBI for future fires in certain regions, while for other regions models may require additional field observations or alternative spectral transformations. Our decision tree schema can be used to help users determine which scale is likely to produce the most accurate results using our models. The CBI regression models developed here, paired with the decision tree, provide users with a simple method to estimate burn severity in units of CBI for any fire within CONUS with moderate to high levels of confidence and provide a template for further development of models with new data going forward.

Assessing geomorphic floodplain models for large scale coarse resolution 2D flood modelling in data scarce regions

River valleys are dynamic living ecosystems of utmost importance for flood attenuation that are shaped by inundation dynamics. Topographic and bathymetric surveys represent pivotal information for accurate and up-to-date floodplain studies. Both floodplain morphology as well as fluvial river cross section and thalweg profiles are required for inundation modelling and mapping. However, economic and technical limitations hinder their availability in some regions, resulting in challenges to build two dimensional (2D) flood wave routing simulations at proper accuracy and resolution. In this study, we assess the effectiveness of characterizing the fluvial morphology by means of geomorphic methods (GMs). Different GMs, used as surrogates of fluvial bathymetry, are tested and compared to a dataset of surveyed natural cross sections available for the Tiber River basin (Italy). Quantitative flood modelling performances are developed using a validated 150 m flood model, providing inundation extent and floodplain flow depths for the 200 years return period event. The ability (or inefficiency) of surrogating the lack of surveyed fluvial bathymetric data with GMs for supporting large scale hydraulic inundation modelling studies is assessed by testing the following 5 floodplain modelling configurations: (1) rectangular shaped cross section; (2) floodplain-based; (3) global river database; (4) linear regression bathymetric relationship; and (5) and a very coarse 700 grid resolution. In addition, two Global Flood Hazard Mapping (GFHM) products (hydrological, and hydrogeomorphic) were used as part of the large scale floodplain modelling evaluation framework. Results demonstrate that, once the fluvial channel flow area is preserved, all tested GM models produce consistent simulation of inundation depths and extents (Fit index ≥ 0.90). This work provides a quantitative assessment of the validity of the hypothesis stressing that the floodplain conveyance capacity is the driving principle of flood inundation dynamics under extreme flooding scenarios. Understanding the role of geomorphology during extreme magnitude floods may support the idea that under specific conditions, high resolution models and detailed topography/bathymetry are surplus to requirements. This work supports the application of geomorphic approaches over large riparian domains as a parsimonious solution for flood hazard mapping in data scarce regions for applications beyond flood mitigation and forecasting.

Post-Colonialism Perspective: Why Turkey's Efforts to Join EU always 'Go Down in Flames'?

European Union (EU) is an economically advanced, politically reliable, socially progressive, and regionally integrated community, making the so-called 'the role model of world's regionalism' seem adorable in Turkey's lens. Having the opportunity to wave its flag in Brussels has been Turkey's foreign policy since 1987. Turkey's modus operandi to make the EU opening its door are enormous in scale. Yet, it does not mean that Turkey would quickly receive a lukewarm response from the EU. This paper lays down some theoretical arguments based on post-colonialism to discover why the EU has given a persistent rejection and derogation towards Turkey. As this paper stands in a post-colonialism stance, the Euro-centrism sense, which is embedded in the EU's way of thought, serves as the reason why intentional rejection is intensively addressed towards Turkey. This paper contains several features. After delivering a short introduction, there will be a modest explanation in picturing the used-theoretical framework. The discussion section stands upon three main questions; why does the EU treat Turkey differently from Greece? Is Turkey capable of fulfilling Copenhagen criteria? Does the EU tend to act in a discriminative manner to Turkey?

A unified route for flavivirus structures uncovers essential pocket factors conserved across pathogenic viruses

The epidemic emergence of relatively rare and geographically isolated flaviviruses adds to the ongoing disease burden of viruses such as dengue. Structural analysis is key to understand and combat these pathogens. Here, we present a chimeric platform based on an insect-specific flavivirus for the safe and rapid structural analysis of pathogenic viruses. We use this approach to resolve the architecture of two neurotropic viruses and a structure of dengue virus at 2.5 Å, the highest resolution for an enveloped virion. These reconstructions allow improved modelling of the stem region of the envelope protein, revealing two lipid-like ligands within highly conserved pockets. We show that these sites are essential for viral growth and important for viral maturation. These findings define a hallmark of flavivirus virions and a potential target for broad-spectrum antivirals and vaccine design. We anticipate the chimeric platform to be widely applicable for investigating flavivirus biology.

Following the Old Road: Organizational Imprinting and the Regional Development of Russia

ABSTRACTIn this article, I draw from organizational imprinting theory to illuminate the impact of the Soviet legacy on contemporary Russian economic geography and regional policy. I argue that central coordination in the creation and regulation of Russian urban agglomerations is connected to a socialist imprinted paradigm associated with the Soviet economic regionalization model and territorial-production complexes (TPCs). I conduct a qualitative historical study to analyze the role of the foundational environment and the dynamics in the development of this imprint. I propose that this imprint effect is prone to reproduction in contemporary regional development strategies and community-based paradigms due to exaptation and cultural-cognitive persistence. The article extends the literature of socialist imprinting by demonstrating how imprints may emerge, transform, and affect localized organizational communities in transition economies and highlights the role of imprinted paradigms in policymaking and regional development.

Development of Strategy for SWAT Hydrologic Modeling in Data-Scarce Regions of Peru

AbstractIn this study, methods were developed to create and evaluate the performance of the Soil and Water Assessment Tool (SWAT) in southern Peru where commonly used input data sources were not av...

Modelling future changes to the hydrological and thermal regime of unaltered streams using projected changes in climate to support planning for sensitive species management

AbstractClimate change will alter stream habitats through precipitation and air temperature changes and potentially threaten species that rely on contemporary streamflow and stream temperature regimes. Habitat projections are therefore critical to inform management decisions. Past and ongoing research has improved streamflow and temperature modelling in ungauged regions, but no studies merge these advancements with climate modelling for regional streamflow and stream temperatures predictions that describe stream habitat change. Here, we predict change in streamflow and stream temperature at the reach scale using projections from downscaled global climate models (GCMs) and the ‘business as usual’ carbon emission scenario. We focus on unaltered streams in six southern California watersheds using data from baseline (1982–2014) and projected end‐of‐century (2082–2100). Stream temperature is projected to increase regionally, with high‐elevation stream reaches increasing most rapidly. There is less consistency in the streamflow projections, but a spatial and temporal homogenization of stream flow characteristics was predicted, that is, flows become more similar across the region with less inter‐annual variation. Additionally, there is a regional trend towards larger high flow magnitudes and more storm events. Despite the increased frequency and magnitude of storm events, high‐elevation streams are predicted to become drier for a greater portion of the year. Conversely, low‐elevation streams are predicted to have longer hydroperiods. Mapping future streamflow and stream temperatures at the reach scale can direct conservation efforts to streams that remain suitable, restoration to areas that decrease in suitability for target species, and support water policies that consider future stream condition.

Modeling Complex Solvent Effects on the Optical Rotation of Chiral Molecules: A Combined Molecular Dynamics and Density Functional Theory Study.

The challenge of assigning the absolute stereochemical configuration to a chiral compound can be overcome via accurate ab initio predictions of optical rotation, a sensitive molecular property that is further complicated by solvent effects. The solvent's "chiral imprint"-the transfer of the chirality from the solute to the surrounding achiral solvent-is explored here using conformational averaging and time-dependent density-functional theory. These complex solvent effects are taken into account via simple averaging over a molecular dynamics trajectory together with the explicit quantum mechanical consideration of the solvent molecules within the solute's cybotactic region and implicit modeling of the bulk solvent. We consider several axes along which the system's optical rotation varies, including the sampling of the dynamical trajectory, the quality of the one-electron basis set, and the use of continuum solvent models to account for bulk effects.

Skin Toxicity Profile of Photon Radiotherapy versus Proton Beam Therapy in Paediatric and Young Adult Patients with Sarcomas

AimsRadiotherapy is key in the management of patients with both Ewing sarcoma and rhabdomyosarcoma. However, there is little evidence in the literature with regards to radiation-induced skin toxicities (RISTs) for patients treated with conventional radiotherapy with X-rays (XRT) or proton beam therapy (PBT) for these two conditions. In the present study we evaluated acute and late RIST in patients treated within European protocols with either PBT or XRT, taking both clinical and dosimetric variables into consideration. Materials and methodsThis was a retrospective analysis of 79 paediatric/young adult patients treated with radical radiotherapy (with XRT or PBT) and concurrent chemotherapy. In all cases, radiotherapy was given in conventional fractionation (1.8 Gy/fraction). Acute and late RISTs were registered according to the Radiation Therapy Oncology Group (RTOG) scoring system. ResultsWith regards to acute RIST, 47.9% (23/48) of XRT patients and 48.4% (15/31) of PBT patients had acute grade 2/3 toxicity. When it comes to late RIST, 17.5% (7/40 with known toxicity profile) of XRT patients and 29.0% (9/31) of PBT patients had grade 1/2 toxicity. This difference of –11.5% (95% confidence interval –31.2 to 7.9%) in grade 1/2 toxicity between XRT and PBT was not statistically significant (P = 0.25). Regardless of the radiotherapy technique, V30Gy seems a good predictor of acute RIST. Moreover, for the same value of V30Gy, patients who receive PBT may have a higher risk of moderate–severe acute RIST. Perhaps due to the small sample, definitive conclusions on the predictive factors of late RIST could not be drawn. ConclusionsNo clinically meaningful differences in acute and late RIST were observed between PBT and XRT subgroups. Systematic differences in the modelling of the build-up region may exist between XRT and PBT algorithms, which could make the comparison of dose metrics between techniques potentially biased. A more comprehensive analysis of dosimetric data on larger patient cohorts is needed to elucidate the most relevant skin dose metrics. Dose-effect models of RIST for this unique patient population would be an invaluable tool in radiotherapy plan optimisation.

Watershed hydrological modelling in data scarce regions; integrating ecohydrology and regionalization for the southern Caspian Sea basin, Iran

The aim of this study is to evaluate an alternative approach to indicate how hydrological processes behave in a given watershed, and to test whether this approach can replace traditional calibration, particularly under data deficient conditions. Therefore, a regional calibration method (RC) was adapted to characterize “parameter-based hydrologic processes” as a function of watershed ecologic attributes. The methodological process included (1) temporal phase, (2) correlation analysis and (3) spatial phase. The defined methodology was carried out on a 4160 km2 area containing 21 watersheds laying in the southern coastal line of the Caspian Sea, Iran. By implementing the RC, regional models were specified corresponding to each hydrological process defined in the Tank model. Testing the reliability of the transferring process of hydrological parameters was conducted using multi-level accuracy comparison (MAC) benefiting from descriptive statistics, scatter-plots and T-test.Both temporal and spatial phases have shown acceptable outputs backed by their ecologic significance, but as an alternative approach to traditional calibration, the standalone RC still needs development to achieve a more robust basis covering all the parameters of the hydrologic model. According to the post-processor MAC, the transferability of six out of twelve regional models (height of lower outlet at the first tank, intermediate flow, deep-percolation, infiltration, surface flow, height of outlet at the second tank) was accepted with respect to the given tests. As such, our method outperformed the number of transferable parameters by an outstanding regional model predicting the surface flow in comparison with similar studies.Although the RC could not achieve total perfection, nevertheless it could still help users by providing more information about the contribution of ecologic variables in the prediction of the hydrological processes of a certain watershed.

Solving Generalized DEA/AR Model With Fuzzy Data and Its Application to Evaluate the Performance of Manufacturing Enterprises

The use of conventional data envelopment analysis (DEA) models in real-world problems are limited because of some restrictions that must be considered in the model such as imprecise or vague data in inputs and outputs as well as additional information or assumptions. One way to handle this problem is by using fuzzy DEA with assurance regions (FDEA/AR) models. There is a common approach in almost all the suggested methods for solving FDEA/AR models. However, in this paper, we show that in some DEA/AR models, applying this approach can be led to inappropriate results. Four theorems are given to provide some sufficient conditions for a DMU to be the DEA/AR efficient. These theorems can be used to check the accuracy of the presented methods for solving FDEA/AR models, too. Moreover, a new method for solving a generalized FDEA/AR model that includes established DEA models such as CCR model (Charnes et al., 1978), BCC model (Banker et al., 1984), FG model (Fare & Grosskopf, 1985), and ST model (Seiford & Thrall, 1990) is proposed. These models are constant, variable, non-decreasing, and non-increasing returns to scale models, respectively. The proposed method is applied to evaluate the performance of manufacturing enterprises.

Ion cyclotron resonance heating fast and slow wave excitation and power deposition in edge plasmas with application to ITER

The antenna power coupling to the plasma centre and its possible deleterious coupling to the plasma edge are key parameters in an ion cyclotron resonance heating system. The influence on these parameters by the confluence between the slow and the fast magnetosonic waves is studied for the case of large machines. Until now, the modelling of the scrape off layer region has been calculated by ANTITER II, which contains only the fast wave description and where the confluence with the slow wave (S wave) is approximated by the Alfvén resonance. In the present study, a complete modelling of the slow and fast waves is made by ANTITER IV. The modelling by the two codes is compared and shows the important role of the Alfvén and the lower hybrid resonances for the excitation of large fields and associated power deposition at the edge of the plasma even far from the antenna location. The ANTITER IV modelling is thereafter applied to the case of the ITER antenna with a reference density profile and heating parameters. A comparative study is made for the edge power deposition and the excitation of large fields for different toroidal phasing cases of the antenna. This study also takes into account the tilting of the antenna array with respect to the total magnetic field in front of the antenna. If the Faraday screen is field-aligned, the excitation of the S wave occurs at the wave confluence; however, in the case of non-alignment the antenna directly excites the S wave. This effect is studied and quantified. All edge effects, even the direct excitation of S waves, can be strongly reduced by tailoring the current distribution in the straps of the antenna array. Resulting cases for the minimisation of edge power deposition in ITER and the reactor are studied.

Physiologically Based Biopharmaceutics Modeling of Regional and Colon Absorption in Dogs.

Colon absorption is a key determinant for the successful development of modified-release (MR) formulations, and the risk that colon absorption may limit the in vivo performance of an MR product can be assessed early by various in vitro tests or by preclinical in vivo regional absorption studies in dogs. Mechanistic physiologically based biopharmaceutics modeling (PBBM) is becoming increasingly accepted to predict in vivo performance and guide formulation development; however, no evaluation of the ability to predict colon absorption has been performed. The purpose of this study was to investigate if regional and colon absorption of drugs in dogs could be predicted with sufficient accuracy using PBBM to enable the replacement of in vivo dog studies in the early assessment of colon absorption limitation risks. This was done by predicting the regional and colon absorption and plasma exposure of 14 drugs after administration to the dog colon according to an a priori approach using the in silico absorption models GI-Sim and GastroPlus. Predictive performance was primarily assessed by comparing observed and predicted plasma concentration–time profiles, AUC0-t, and the relative bioavailability in the colon (Frel,colon) as compared to an oral/duodenal reference. Trends in dependency of prediction performance on predicted fraction absorbed, permeability, and solubility/dissolution rate were also investigated. For GI-Sim, the absolute average fold error (AAFE) values for AUC0-t and Frel,colon were within a 2-fold prediction error for both solutions (1.88 and 1.51, respectively) and suspensions (1.58 and 1.99, respectively). For GastroPlus, the AAFE values for AUC0-t and Frel,colon were outside the set 2-fold prediction error limit for accurate predictions for both solutions (3.63 and 2.98, respectively) and suspensions (2.94 and 2.09, respectively). No trends for over- or underprediction were observed for GI-Sim, whereas GastroPlus showed a slight trend for underprediction of both AUC0-t and Frel,colon for compounds with low permeability. In addition, regional differences in the plasma profiles were qualitatively predicted in the majority of cases for both software. Despite the differences in prediction performance, both models can be considered to predict regional differences in absorption as well as AUC0-t and Frel,colon with acceptable accuracy in an early development setting. The results of this study indicate that it is acceptable to replace in vivo regional absorption studies in dogs with the evaluated models as a method for the early assessment of the risk for colon absorption limitation of MR drug product candidates.