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1.
Chaos ; 31(1): 013110, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33754747

RESUMO

This work investigates the multi-fractal nature of a turbulent urban atmosphere using high-resolution atmospheric data. Meteorological and concentration measurements of passive and reactive pollutants collected over a 3-year period in a sub-urban high-Reynolds number atmospheric field were analyzed. Scaling laws characterizing the self-similarity and thereby depicting the multi-fractal nature are determined by calculating the singularity spectra, where a range of Hölder exponents, h, are estimated. In doing so, the complexity of the urban atmosphere entailing different stability regimes was addressed. Using the Monin-Obukhov length (LMO) as a marker of atmospheric stability and thereby an indication of the magnitude of anisotropy, we find where and how self-similarity is manifested relative to the different regimes and we estimate corresponding appropriate scaling laws. We find that the wind speed obeys the -5/3 law suggested by Kolmogorov only when the atmosphere lies within the stable regime as defined by Monin-Obukhov theory. Specifically, when the ratio of the atmospheric boundary layer height (Hb.l) over LMO is greater than 15, and at the same time, the ratio of the height above ground of the wind measurements (z0) over LMO is higher than 3 (i.e., in stable regime), then the singularity spectra of wind speed time series indicate that the dominant Hölder exponent, hmax, coincides with Kolmogorov's second hypothesis. On the contrary under unstable regimes in the atmosphere where the anisotropy is approached, different scaling laws are estimated. In detail, when z0/LMO<0, the dominant Hölder exponent, hmax, of the singularity spectra of the wind speed time series is either negative or close to zero, which is an indication of an impulse-like singularity, that is associated with rapid changes. For the ambient temperature and air quality measurements such as of carbon monoxide and particulate matter concentrations, it was found that they obey different laws, which are related with the long-term correlation of their data fluctuation.

2.
Open Res Eur ; 1: 128, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-37994356

RESUMO

The FLEXGRID 2 project develops a digital platform designed to offer Digital Energy Services (DESs) that facilitate energy sector stakeholders (i.e. DSOs, TSOs, market operators, RES producers, retailers, flexibility aggregators) towards: i) automating and optimizing their investments and operation/management of their systems/assets, and ii) interacting in a dynamic and efficient way with their environment (electricity system) and the rest of the stakeholders. In this way, FLEXGRID envisages secure, sustainable, competitive, and affordable smart grids. A key objective is the incentivization of large-scale bottom-up investments in Distributed Energy Resources (DERs) through innovative smart grid management. Towards this goal, FLEXGRID develops innovative data models and energy market architectures (with high liquidity and efficiency) that effectively manage smart grids through an advanced TSO-DSO interaction as well as interaction between Transmission Network and Distribution Network level energy markets. Consequently, and through intelligence that exploits the innovation of the proposed market architecture, FLEXGRID develops investment tools able to examine in depth the emerging energy ecosystem and allow in this way: i) the financial sustainability of DER investors, and ii) the market liquidity/efficiency through advanced exploitation of DERs and intelligent network upgrades.

3.
Health Care Manag Sci ; 21(2): 259-268, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28401405

RESUMO

As an aid to predicting future hospital admissions, we compare use of the Multinomial Logit and the Utility Maximising Nested Logit models to describe how patients choose their hospitals. The models are fitted to real data from Derbyshire, United Kingdom, which lists the postcodes of more than 200,000 admissions to six different local hospitals. Both elective and emergency admissions are analysed for this mixed urban/rural area. For characteristics that may affect a patient's choice of hospital, we consider the distance of the patient from the hospital, the number of beds at the hospital and the number of car parking spaces available at the hospital, as well as several statistics publicly available on National Health Service (NHS) websites: an average waiting time, the patient survey score for ward cleanliness, the patient safety score and the inpatient survey score for overall care. The Multinomial Logit model is successfully fitted to the data. Results obtained with the Utility Maximising Nested Logit model show that nesting according to city or town may be invalid for these data; in other words, the choice of hospital does not appear to be preceded by choice of city. In all of the analysis carried out, distance appears to be one of the main influences on a patient's choice of hospital rather than statistics available on the Internet.


Assuntos
Comportamento de Escolha , Hospitais/estatística & dados numéricos , Modelos Teóricos , Inglaterra , Hospitais/normas , Humanos , Fatores de Tempo , Meios de Transporte
4.
Drugs ; 63(14): 1481-8, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12834365

RESUMO

In acute exacerbation of chronic obstructive pulmonary disease (AECOPD), short-acting inhaled bronchodilators, such as salbutamol (albuterol) and ipratropium bromide, have proven useful. In patients who are refractory to these agents, intravenous aminophylline should be considered. Corticosteroids should also be used, either in the outpatient or inpatient setting. The duration of corticosteroids should probably not exceed 2 weeks and the optimum dosage is yet to be determined. Antibacterials, especially in patients with purulent or increased sputum, should be used, guided by the local antibiogram of the key microbes. Controlled oxygen therapy improves outcome in hypoxaemic patients and arterial blood gases should be performed to ensure hypercarbia is not becoming excessive. Should patients be in distress despite the above measures or if there is acidaemia or hypercarbia, noninvasive positive pressure ventilation could be used to improve outcomes without resorting to invasive mechanical ventilation. Mucous-clearing drugs and chest physiotherapy have no proven beneficial role in AECOPD.


Assuntos
Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Corticosteroides/uso terapêutico , Animais , Antibacterianos/uso terapêutico , Broncodilatadores/uso terapêutico , Humanos , Oxigenoterapia/métodos , Doença Pulmonar Obstrutiva Crônica/complicações , Doença Pulmonar Obstrutiva Crônica/fisiopatologia
5.
Postgrad Med ; 113(1): 79-82, 85-8, 91-2, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12545594

RESUMO

Pneumonia that fails to resolve after 10 to 14 days of antibiotic therapy can lead physicians to call for consultation or unnecessary invasive diagnostic procedures. Understanding the infectious and noninfectious causes of pneumonia and their normal times to resolution is enormously helpful in the judicious evaluation of and timely intervention in this very challenging condition.


Assuntos
Resistência Microbiana a Medicamentos , Pneumopatias/diagnóstico , Pneumopatias/etiologia , Infecções Oportunistas/diagnóstico , Infecções Oportunistas/microbiologia , Pneumonia/diagnóstico , Pneumonia/microbiologia , Fatores Etários , Idoso , Infecções Comunitárias Adquiridas/microbiologia , Árvores de Decisões , Humanos , Pneumopatias/diagnóstico por imagem , Infecções Oportunistas/diagnóstico por imagem , Pneumonia/diagnóstico por imagem , Radiografia , Fatores de Tempo , Procedimentos Desnecessários
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