scholarly journals Effective approach to epidemic containment using link equations in complex networks

2018 ◽  
Vol 4 (12) ◽  
pp. eaau4212 ◽  
Author(s):  
Joan T. Matamalas ◽  
Alex Arenas ◽  
Sergio Gómez
Keyword(s):  
Complex Networks ◽  
Large Scale ◽  
Accurate Determination ◽  
Air Transportation ◽  
Disease Spread ◽  
Epidemic Spreading ◽  
Critical Thresholds ◽  
Full Structure ◽  
The Impact

Epidemic containment is a major concern when confronting large-scale infections in complex networks. Many studies have been devoted to analytically understand how to restructure the network to minimize the impact of major outbreaks of infections at large scale. In many cases, the strategies are based on isolating certain nodes, while less attention has been paid to interventions on the links. In epidemic spreading, links inform about the probability of carrying the contagion of the disease from infected to susceptible individuals. Note that these states depend on the full structure of the network, and its determination is not straightforward from the knowledge of nodes’ states. Here, we confront this challenge and propose a set of discrete-time governing equations that can be closed and analyzed, assessing the contribution of links to spreading processes in complex networks. Our approach allows a scheme for the containment of epidemics based on deactivating the most important links in transmitting the disease. The model is validated in synthetic and real networks, yielding an accurate determination of epidemic incidence and critical thresholds. Epidemic containment based on link deactivation promises to be an effective tool to maintain functionality of networks while controlling the spread of diseases, such as disease spread through air transportation networks.

scholarly journals Sulfur dioxide layer height retrieval from Sentinel-5 Precursor/TROPOMI using FP_ILM

2019 ◽  
Vol 12 (10) ◽  
pp. 5503-5517 ◽  
Author(s):  
Pascal Hedelt ◽  
Dmitry S. Efremenko ◽  
Diego G. Loyola ◽  
Robert Spurr ◽  
Lieven Clarisse
Keyword(s):  
Sulfur Dioxide ◽  
Accurate Determination ◽  
Volcanic Eruptions ◽  
Critical Parameters ◽  
Layer Height ◽  
Learning Machine ◽  
The Impact ◽  
First Time ◽  
Better Than

Abstract. The accurate determination of the location, height, and loading of sulfur dioxide (SO2) plumes emitted by volcanic eruptions is essential for aviation safety. The SO2 layer height is also one of the most critical parameters with respect to determining the impact on the climate. Retrievals of SO2 plume height have been carried out using satellite UV backscatter measurements, but, until now, such algorithms are very time-consuming. We have developed an extremely fast yet accurate SO2 layer height retrieval using the Full-Physics Inverse Learning Machine (FP_ILM) algorithm. This is the first time the algorithm has been applied to measurements from the TROPOMI instrument onboard the Sentinel-5 Precursor platform. In this paper, we demonstrate the ability of the FP_ILM algorithm to retrieve SO2 plume layer heights in near-real-time applications with an accuracy of better than 2 km for SO2 total columns larger than 20 DU. We present SO2 layer height results for the volcanic eruptions of Sinabung in February 2018, Sierra Negra in June 2018, and Raikoke in June 2019, observed by TROPOMI.

scholarly journals Simulating pollutant transport over complex terrain: the hydrological component

2012 ◽  
Vol 10 (4) ◽  
pp. 1223-1235 ◽  
Author(s):  
Constantina Mita ◽  
Nicolaos Catsaros
Keyword(s):  
Channel Flow ◽  
Accurate Determination ◽  
Ground Surface ◽  
Pollutant Transport ◽  
Surface Flow ◽  
Valuable Insight ◽  
Distributed Hydrological Model ◽  
Channel Network ◽  
The Impact

AbstractThe accurate determination of surface water flow pathways is of primary importance when assessing the impact of pollutant transport and watershed physical characteristics on overland and channel water quality. The mathematical description of hydrological processes over natural watersheds, requires a detailed representation of the topography, on which the accurate determination of overland and channel flow trajectories often poses difficulties. The hydrological component of the DELTA code aims to provide valuable insight into this direction by using the semi-irregular triangulated (semi-TIN) topography model DELTA/HYDRO for establishing surface flow paths that can represent reliably the natural characteristics of a watershed, addressing several major physical hydrodynamic processes. The validity of the generated paths is tested via the integration of a conventional distributed hydrological model by routing excess rainfall over ground surface and through a channel network to the watershed outlet, for a series of storm episodes on a small, but relatively complex watershed. The encouraging results obtained demonstrate the promising application potential of the model, which can be additionally complemented with a pollutant transport component to address the interactions of soluble chemicals between soil surface and overland/channel flow, in the context of a fully integrated model.

Determining FAC Degradation From NDE Data

2009 ◽  
Author(s):  
Harold M. Crockett ◽  
Jeffrey S. Horowitz
Keyword(s):  
Error Propagation ◽  
Power Plants ◽  
Degradation Mechanism ◽  
Accurate Determination ◽  
Wear Rates ◽  
Flow Acceleration ◽  
Inspection Data ◽  
Evaluation Approaches ◽  
The Impact

Flow-acceleration corrosion (FAC) is a degradation mechanism that impacts carbon steel piping components and equipment under conditions often found in both nuclear and fossil power plants. To deal with this type of degradation, many utilities have instituted inspection programs designed to discover dangerous situations well before failures occur. Inspections to determine FAC damage are normally done using the Ultrasonic Technique (UT) although other methods are also used. For large bore components, the most commonly used inspection approach is gridded UT measurements. Experience has shown that the amount of degradation that typically occurs between inspections is comparable to the uncertainty of the UT measurements. Thus, the accurate determination of the actual wear rates is difficult as the measurement uncertainties tend to cause over-stating the actual degradation. To deal with this problem, EPRI has developed a number of evaluation approaches for interpreting data from one inspection, from two sets of inspections and from more than two sets of inspections. The application of these methods to inspection data will be discussed demonstrating the performance of the different approaches. The impact of the error propagation on the accuracy of these methods and recommendations for different circumstances will be presented.

scholarly journals The COVID-19 Pandemic as a Social Stressor: Psychological and Psychiatric Risk Factors (Based on Foreign Studies)

2020 ◽  
Vol 11 (4) ◽  
pp. 13-25
Author(s):  
Z.V. Lukovtseva
Keyword(s):  
Risk Factors ◽  
Large Scale ◽  
Psychiatric Care ◽  
Psychological Characteristics ◽  
Diagnostic Tools ◽  
Individual Factors ◽  
Main Factors ◽  
The Impact ◽  
Psychiatric Problems

Objective. Systematization of the main factors of psychological and psychiatric risk during the COVID-19 pandemic, identified in foreign studies. Background. The need to clarify ideas about the determination of psychological and psychiatric problems caused by the socially stressful impact of the COVID-19 pandemic is dictated primarily by the demands of practice. The relevance of actions in this direction is determined by the continuing instability of the epidemiological and socio-economic situation, the need for prompt and wide coverage of those in need with programs of psychological and psychiatric care, the fragmentation and inconsistency of existing information about the impact of the pandemic on the mental health of the population. Methodology. A theoretical analysis of literature sources describing foreign studies of psychological and psychiatric risk factors against the background of a pandemic was carried out; using a comparative analytical method, the meaning and degree of knowledge of situational and individual factors are determined. Conclusions. The general features of studies conducted by psychologists and psychiatrists from different countries against the background of the coronavirus threat were revealed (the predominance of the remote format, the reduction in the variety and volume of diagnostic tools, the use of large-scale samples). The main factors of psychological and psychiatric risk affecting the population in the context of the spread of coronavirus are divided into situational and individual. The factors of the first group are differentiated according to their degree of specificity for the COVID-19 pandemic, while in the second group, socio-demographic and medico-psychological factors are distinguished. It is shown that individual psychological characteristics that can determine the nature of a person’s response to a pandemic remain the least studied and clarification of their composition is an urgent scientific and practical task.

scholarly journals Quicker Measurement of Walls’ Thermal Resistance Following an Extension to ISO 9869 Average Method

2019 ◽  
Vol 111 ◽  
pp. 04019
Author(s):  
Arash Rasooli ◽  
Laure Itard
Keyword(s):  
Heat Flux ◽  
Thermal Resistance ◽  
Average Method ◽  
Large Scale ◽  
Accurate Determination ◽  
Acceptable Result ◽  
Heat Flux Meter ◽  
The Difference

Determination of the thermo-physical characteristics of the buildings’ components is crucial to illustrate their thermal behavior and therefore their energy consumption. Along the same line, accurate determination of the thermal resistance of the building walls falls into one the most important targets. Following the difference between in-lab, and on site thermal performance of walls, in-situ measurements have been highly recommended. The most well-known practice for in-situ measurement of walls’ thermal resistance is the Average Method of ISO 9869, using one heat flux meter and two thermocouples. The method, in comparison with other existing methods is quite straight-forward and therefore, is applied widely in large scale. Despite its simplicity, this method usually needs a relatively long time to reach an acceptable result. The current paper deals with a modification to the ISO 9869 method, making it in many situations much quicker than its original state. Through simulation of walls of different typologies, it is shown in which cases the measurement period becomes longer than expected. It is demonstrated how the addition of a heat flux meter to the aforementioned equipment can lead to a much quicker achievement of the thermal resistance, following the rest of the instructions of the standard method.

scholarly journals Magnetopause current as seen by Cluster

2005 ◽  
Vol 23 (3) ◽  
pp. 901-907 ◽  
Author(s):  
M. W. Dunlop ◽  
A. Balogh
Keyword(s):  
Magnetic Field ◽  
Electric Current ◽  
Large Scale ◽  
Field Component ◽  
Accurate Determination ◽  
Field Measurements ◽  
Magnetic Field Component ◽  
Boundary Crossing ◽  
Current Layer

Abstract. The four-spacecraft, magnetic field measurements on Cluster can be combined to produce an accurate determination of the electric current in the magnetopause boundary during stable magnetopause crossings. For events that are planar on the scale of the spacecraft configuration, the thickness of the current layer can be accurately estimated from its magnetic profile at each spacecraft and the corresponding boundary crossing times. The latter, give a determination of boundary motion relative to the Cluster array. We use the estimates of all these properties, for a range of spacecraft separation distances, to show, firstly, that the estimate of electric current density is representative even when the spatial scale of the configuration of Cluster spacecraft approaches the thickness of the current layer. Secondly, we show that the estimated current lies in the plane of the boundary and demonstrate this for crossings occurring during large-scale ripples on the magnetopause. Thirdly, we show that the magnitude of the current is accurately represented, averaged over the extent of the current layer, by comparing to the change in the boundary-parallel magnetic field component divided by the estimated current layer thickness. We demonstrate this last point using a range of crossings each having a different thickness and crossing speed, different changes in the magnetic field component and different current densities.

Improving quality of care and reducing costs with angiogenesis-specific imaging tests in metastatic breast cancer.

2012 ◽  
Vol 30 (34_suppl) ◽  
pp. 150-150
Author(s):  
Carolyn Bodnar ◽  
L. Clark Paramore ◽  
Kevin B. Knopf
Keyword(s):  
Breast Cancer ◽  
Quality Of Care ◽  
Metastatic Breast Cancer ◽  
Accurate Determination ◽  
Metastatic Breast ◽  
Base Case ◽  
Test Results ◽  
The Impact

150 Background: Anti-angiogenesis (AA) drugs (e.g., bevacizumab) are expensive and their clinical benefit in metastatic breast cancer (MBC) has been challenged. Healthcare reform and financial pressures prioritize programs which improve patient quality of care and reduce costs of unnecessary care. Angiogenesis-specific imaging tests (A-IT) under development have potential to offer earlier, accurate determination of response. For A-IT-identified responders, AA treatment would be continued. For patients identified as non-responders, futile AA treatment and associated toxicities can be avoided and alternative therapies initiated. Methods: A decision-tree model was developed to estimate the impact of A-IT from determination of AA therapy eligibility through to disease progression. Key decision nodes were presence/absence of A-IT (assessing change in biomarker expression across 2 PET/CT scans: at AA eligibility, then after one cycle of AA), A-IT sensitivity/specificity (SE/SP) and clinician adherence to test results (tied to belief that results are valid enough to stop AA therapy). Key model inputs (and base case values): 1) median time to progression (TTP) for current MBC patients on AA therapies (9.5 months); 2) median TTP for A-IT identified responders (13 months); 3) costs of bevacizumab, one cycle ($5,200); 4) percentage of AA patients with hemorrhage (4%); 5) costs of hemorrhaging, per event ($14,694); 6) per patient costs for A-IT ($6,000); 7) estimated SE/SP of A-IT – 95%/75%; and 8) clinician adherence to test results (75%). Results: Based on a cohort of 100 MBC patients, use of A-IT results in 29 patients avoiding futile AA therapy with a saving of $460,000, versus a scenario where A-IT was not used. One-way threshold sensitivity analysis shows A-IT is cost-saving if SP >62% or when clinician adherence is ≥63%; results are not sensitive to AA hemorrhage rate. Conclusions: Use of A-IT could improve quality of care by optimizing AA therapy, i.e., by identifying responders who will experience survival benefit and non-responders who can avoid futile therapy and toxicity risks. Significant cost savings may be possible as a result of early determination of response to AA drugs.

Defect concentration and Δn change in light- and elevated temperature- induced degradation

2021 ◽  
Author(s):  
Moonyong Kim ◽  
Matthew Wright ◽  
Daniel Chen ◽  
Catherine Chan ◽  
Alison Ciesla ◽  
...  
Keyword(s):  
Surface Passivation ◽  
Defect Density ◽  
Accurate Determination ◽  
Defect Concentration ◽  
Doping Density ◽  
Lifetime Analysis ◽  
Materials Used ◽  
New Formulation ◽  
The Impact

Abstract The wide variety of silicon materials used by various groups to investigate LeTID make it difficult to directly compare the defect concentrations (Nt) using the typical normalised defect density (NDD) metric. Here, we propose a new formulation for a relative defect concentration (β) as a correction for NDD that allows flexibility to perform lifetime analysis at arbitrary injection levels (Δn), away from the required ratio between Δn and the background doping density (Ndop) for NDD of Δn/N dop = 0.1. As such, β allows for a meaningful comparison of the maximum degradation extent between different samples in different studies and also gives a more accurate representative value to estimate the defect concentration. It also allows an extraction at the cross-over point in the undesirable presence of iron, or flexibility to reduce the impact of modulation in surface passivation. Although the accurate determination of β at a given Δn requires knowledge of the capture cross-section ratio (k), the injection-independent property of the β formulation allows a self-consistent determination of k. Experimental verification is also demonstrated for boron-oxygen related defects and LeTID defects, yielding k-values of 10.6 ± 3.2 and 30.7 ± 4.0, respectively, which are within the ranges reported in the literature. With this, when extracting the defect density at different Δn ranging between 1014 /cm3 to 1015 /cm3 with Ndop = 9.1 ×1015 /cm3, the error is less than 12% using β, allowing for a greatly improved understanding of the defect concentration in a material.

scholarly journals Targeted LC-MS/MS platform for the comprehensive determination of peptides in the kallikrein-kinin system

2021 ◽  
Author(s):  
Tanja Gangnus ◽  
Bjoern B. Burckhardt
Keyword(s):  
Healthy Volunteers ◽  
Clinical Symptoms ◽  
Matrix Effects ◽  
Accurate Determination ◽  
Kinin System ◽  
Carry Over ◽  
Kallikrein Kinin System ◽  
The Impact

AbstractThe kallikrein-kinin system (KKS) is involved in many physiological and pathophysiological processes and is assumed to be connected to the development of clinical symptoms of angioedema or COVID-19, among other diseases. However, despite its diverse role in the regulation of physiological and pathophysiological functions, knowledge about the KKS in vivo remains limited. The short half-lives of kinins, their low abundance and structural similarities and the artificial generation of the kinin bradykinin greatly hinder reliable and accurate determination of kinin levels in plasma. To address these issues, a sensitive LC-MS/MS platform for the comprehensive and simultaneous determination of the four active kinins bradykinin, kallidin, des-Arg(9)-bradykinin and des-Arg(10)-kallidin and their major metabolites bradykinin 2-9, bradykinin 1-7 and bradykinin 1-5 was developed. This platform was validated according to the bioanalytical guideline of the US Food and Drug Administration regarding linearity, accuracy, precision, sensitivity, carry-over, recovery, parallelism, matrix effects and stability in plasma of healthy volunteers. The validated platform encompassed a broad calibration curve range from 2.0–15.3 pg/mL (depending on the kinin) up to 1000 pg/mL, covering the expected concentrations in disease states. No source-dependent matrix effects were identified, and suitable stability of the analytes in plasma was observed. The applicability of the developed platform was proven by the determination of endogenous levels in healthy volunteers, whose plasma kinin levels were successfully detected in the low pg/mL range. The established platform facilitates the investigation of kinin-mediated diseases (e.g. angioedema, COVID-19) and enables the assessment of the impact of altered enzyme activities on the formation or degradation of kinins. Graphical abstract

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