The Study of Quantum Interference in Metallic Photonic Crystals Doped with Four-Level Quantum Dots

In this work, the absorption coefficient of a metallic photonic crystal doped with nanoparticles has been obtained using numerical simulation techniques. The effects of quantum interference and the concentration of doped particles on the absorption coefficient of the system have been investigated. The nanoparticles have been considered as semiconductor quantum dots which behave as a four-level quantum system and are driven by a single coherent laser field. The results show that changing the position of the photonic band gap about the resonant energy of the two lower levels directly affects the decay rate, and the system can be switched between transparent and opaque states if the probe laser field is tuned to the resonance frequency. These results provide an application for metallic nanostructures in the fabrication of new optical switches and photonic devices

Livestock browsing affects the species composition and structure of cloud forest in the Dhofar Mountains of Oman

Questions: It is frequently reported that overstocking of camels, cattle and goats is degrading the Anogeissus cloud forest, which is endemic to a 200 km stretch of coastal mountains in southern Arabia. However, livestock impacts on the vegetation have not been assessed. Furthermore, we have a limited understanding of the impacts of large-bodied browsing livestock, such as camels, in woodland and forest rangelands. Therefore, in this study, we examine the effects of livestock browsing on the species composition, density, and hytomorphology of woody vegetation in the Anogeissus cloud forests in the Dhofar Mountains of Oman. Location: Data was collected at 30 sites in the Jabal Qamar mountain range in western Dhofar, Oman. Methods: The point-centered quarter method was used to sample the composition, density and structure of woody vegetation. Constrained correspondence analysis was used to quantify the effects of livestock browsing on woody plant species composition, whilst effects on plant density were analysed using mixed effects models. Standardised major axis regression was used to examine differences in height-diameter allometry (stunting) under different stocking rates. Results: Fog density, topographic position and long-term stocking rates were found to be important factors affecting woody species composition. We found lower species diversity and plant density, and higher frequencies of unpalatable species, under higher stocking rates. Juveniles showed a stronger response to stocking rates than adults, and several common species exhibited stunted morphology under high stocking rates. Conclusions: Browsing by large-bodied livestock, such as camels and cattle, can substantially alter the species composition, structure, and phytomorphology of woody vegetation in semi-arid woodlands and forests. Juveniles are particularly susceptible to browsing which alters woody vegetation demography and inhibits regeneration potential. Our results support previous suggestions of overstocking in Dhofar and highlight the importance of swift measures to reduce livestock browsing pressure in the Anogeissus cloud forests

Clinical standards for the diagnosis and management of asthma in low- and middle-income countries

BACKGROUND: The aim of these clinical standards is to aid the diagnosis and management of asthma in low-resource settings in low- and middle-income countries (LMICs). METHODS: A panel of 52 experts in the field of asthma in LMICs participated in a two-stage Delphi process to establish and reach a consensus on the clinical standards. RESULTS: Eighteen clinical standards were defined: Standard 1, Every individual with symptoms and signs compatible with asthma should undergo a clinical assessment; Standard 2, In individuals (>6 years) with a clinical assessment supportive of a diagnosis of asthma, a hand-held spirometry measurement should be used to confirm variable expiratory airflow limitation by demonstrating an acute response to a bronchodilator; Standard 3, Pre- and post-bronchodilator spirometry should be performed in individuals (>6 years) to support diagnosis before treatment is commenced if there is diagnostic uncertainty; Standard 4, Individuals with an acute exacerbation of asthma and clinical signs of hypoxaemia or increased work of breathing should be given supplementary oxygen to maintain saturation at 94–98%; Standard 5, Inhaled short-acting beta-2 agonists (SABAs) should be used as an emergency reliever in individuals with asthma via an appropriate spacer device for metered-dose inhalers; Standard 6, Short-course oral corticosteroids should be administered in appropriate doses to individuals having moderate to severe acute asthma exacerbations (minimum 3–5 days); Standard 7, Individuals having a severe asthma exacerbation should receive emergency care, including oxygen therapy, systemic corticosteroids, inhaled bronchodilators (e.g., salbutamol with or without ipratropium bromide) and a single dose of intravenous magnesium sulphate should be considered; Standard 8, All individuals with asthma should receive education about asthma and a personalised action plan; Standard 9, Inhaled medications (excluding dry-powder devices) should be administered via an appropriate spacer device in both adults and children. Children aged 0–3 years will require the spacer to be coupled to a face mask; Standard 10, Children aged <5 years with asthma should receive a SABA as-needed at step 1 and an inhaled corticosteroid (ICS) to cover periods of wheezing due to respiratory viral infections, and SABA as-needed and daily ICS from step 2 upwards; Standard 11, Children aged 6–11 years with asthma should receive an ICS taken whenever an inhaled SABA is used; Standard 12, All adolescents aged 12–18 years and adults with asthma should receive a combination inhaler (ICS and rapid onset of action long-acting beta-agonist [LABA] such as budesonide-formoterol), where available, to be used either as-needed (for mild asthma) or as both maintenance and reliever therapy, for moderate to severe asthma; Standard 13, Inhaled SABA alone for the management of patients aged >12 years is not recommended as it is associated with increased risk of morbidity and mortality. It should only be used where there is no access to ICS. The following standards (14–18) are for settings where there is no access to inhaled medicines. Standard 14, Patients without access to corticosteroids should be provided with a single short course of emergency oral prednisolone; Standard 15, Oral SABA for symptomatic relief should be used only if no inhaled SABA is available. Adjust to the individual’s lowest beneficial dose to minimise adverse effects; Standard 16, Oral leukotriene receptor antagonists (LTRA) can be used as a preventive medication and is preferable to the use of long-term oral systemic corticosteroids; Standard 17, In exceptional circumstances, when there is a high risk of mortality from exacerbations, low-dose oral prednisolone daily or on alternate days may be considered on a case-by-case basis; Standard 18. Oral theophylline should be restricted for use in situations where it is the only bronchodilator treatment option available. CONCLUSION: These first consensus-based clinical standards for asthma management in LMICs are intended to help clinicians provide the most effective care for people in resource-limited settings

Étude des implications financières, institutionnelles et opérationnelles du transfert vers la Région de Bruxelles-Capitale des compétences communautaires dans le cadre d'une possible 7ème réforme de l'État

info:eu-repo/semantics/publishe