57 research outputs found

    Effect of the land use change characteristics on the air pollution patterns above the greater Athens area (GAA) after 2004

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    The Attica Peninsula has experienced the rapid expansion of the Athens urban area, prior to the Athens 2004 Olympics. As a result, the distribution of pollutant sources and emission patterns has changed with a subsequent effect on the distribution of photochemical pollutants and aerosols. The purpose of the present work is to perform a comparative study of the land use changes in the rapidly developing Attica Peninsula including the Greater Athens Area (GAA) before and after 2004, the year that the Olympic Games took place, as well as of the effect of these changes on the respective pollutant distribution profiles. The land use data were provided by USGS Global Land Use/Land Cover version 2.0 Database and the updating process was fulfilled with the help of a satellite image. The area was divided into cells using a spatial resolution of 5x5 km2. Results showed that the urban grid has expanded considerably the past fifteen years while a great shift of population has been made to the eastern area of Attica. Also, new towns were created while others expanded and many factories moved out of the center of the city of Athens. Moreover, the forest land has decreased considerably in the Attica Peninsula either by continuous and extended fires or by the residential burst. The Comprehensive Air Quality Model with extensions (CAMx) was used in order to estimate O3 distribution during a recorded pollution episode. Results revealed that land use changes affected slightly the O3 concentrations and the development of a new emission inventory related to the new LULC field is necessary

    Assimilation of numerical study of the distribution of ozone above the greater Athens area (GAA)

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    Air pollution is considered to be a critical environmental problem of large urban areas posing a threat to human health because of elevated concentrations of pollutants such as O3, NOx, VOCs and PM. In the past decades the GAA has experienced rapid expansion of the urban grid. Thus, the current study aims to examine the distribution of ozone above the GAA, with the help of the photochemical model CAMx, and assess the contribution of multiple geographical source areas, boundary and initial conditions to ozone formation. Results showed that the transport of primary and secondary pollutants can affect the air quality of the receptor area. Many pollution episodes reported to ground stations are often due to the development of a local circulation system (sea breeze) that disperses intense pollutant emissions. Moreover, the boundary and initial conditions used in numerical studies play a significant role to the ozone formation

    Intravitreal injection of Ozurdex(®) implant in patients with persistent diabetic macular edema, with six-month follow-up

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    AIM: To evaluate the efficacy of intravitreal dexamethasone injections in diabetic macular edema (DME). METHODS: A 700 μg slow-release intravitreal dexamethasone implant (Ozurdex®) was placed in the vitreal cavity of 17 patients (19 eyes) affected with persistent DME. Best corrected visual acuity (BCVA) was assessed through Early Treatment Diabetic Retinopathy Study (ETDRS). Central macular thickness (CMT) was measured by spectral-domain optical coherence tomography. BCVA and CMT examinations were carried out at baseline (T0) and repeated after three days, one month (T1), three months (T3), four months (T4), and six months (T6) post injection. RESULTS: Dexamethasone implant induced an improvement in ETDRS at T1, T3, T4, and T6 post injection. CMT was reduced at T1, T3, and T4, while at T6, CMT values were not statistically different from baseline. No complications were observed during the follow-up. CONCLUSION: Our data suggest that dexamethasone implant is effective in reducing DME symptoms within a six-month frame

    Lorentz-Lorenz Coefficient, Critical Point Constants, and Coexistence Curve of 1,1-Difluoroethylene

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    We report measurements of the Lorentz-Lorenz coefficient density dependence, the critical temperature, and the critical density, of the fluid 1,1-difluoroethylene. Lorentz-Lorenz coefficient data were obtained by measuring refractive index and density of the same fluid sample independently of one another. Accurate determination of the Lorentz-Lorenz coefficient is necessary for transformation of refractive index data into density data from optics-based experiments on critical phenomena of fluid systems done with different apparatus, with which independent measurement of the refractive indes and density is not possible. Measurements were made along the coexistence curve of the fluid and span the density range 0.01 to 0.80 g/cc. The Lorentz-Lorenz coefficient results show a stronger density dependence along the coexistence curve than previously observed in other fluids, with a monotonic decrease from a density of about 0.2 g/cc onwards, and an overall variation of about 2.5% in the density range studied. No anomaly in the Lorentz-Lorenz coefficient was observed near the critical density. The critical temperature is measured at Tc=(302.964+-0.002) K (29.814 C) and the measured critical density is (0.4195+-0.0018)g/cc.Comment: 14 pages, 6 figures, MikTeX 2.4, submitted to Physical Review

    Optical Studies of the coexistence curve of the n-heptane+nitrobenzene mixture near its consolute point measured by an optical method

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    We have measured the coexistence curve of the binary liquid mixture n-heptane+nitrobenzene near its consolute point using an optical method. In particular, the critical exponent beta describing the coexistence curve was measured for this system. Previous experimental values of beta for n-heptane+nitrobenzene were higher than the typical theoretically calculated value, an unusual, although not unique, occurrence. In an effort to study this discrepancy, we have used an improved experimental apparatus for our measurements. We have taken special care to minimize temperature gradients and maximize the temperature stability of our thermal control system. We have also exploited features of a known optical method to analyze, thoroughly, sources of systematic errors. We measured an apparent value of beta as 0.367+/- 0.006 and by a careful study of the known sources of error we find that they are not able to remove the discrepancy between the measured and the theoretical values of beta. We also measured the critical temperature of the system at Tc=291.80+/- 0.02 K (18.65 C).Comment: 21 pages, 8 figures, submitted to Physical Review B. Shrunk Experimental section, expanded Equilibration and Conclusion sections, eliminated a figure, added reference; 19 pages, 7 figures, resubmitted to PRB. Replaced Fig. 3, added separate simple text file with coexistence curve data (OPvsT.txt); resubmitted to PR

    High resolution structural evidence suggests the Sarcoplasmic Reticulum forms microdomains with acidic stores (lysosomes) in the heart

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    Nicotinic Acid Adenine Dinucleotide Phosphate (NAADP) stimulates calcium release from acidic stores such as lysosomes and is a highly potent calcium-mobilising second messenger. NAADP plays an important role in calcium signalling in the heart under basal conditions and following β-adrenergic stress. Nevertheless, the spatial interaction of acidic stores with other parts of the calcium signalling apparatus in cardiac myocytes is unknown. We present evidence that lysosomes are intimately associated with the sarcoplasmic reticulum (SR) in ventricular myocytes; a median separation of 20 nm in 2D electron microscopy and 3.3 nm in 3D electron tomography indicates a genuine signalling microdomain between these organelles. Fourier analysis of immunolabelled lysosomes suggests a sarcomeric pattern (dominant wavelength 1.80 μm). Furthermore, we show that lysosomes form close associations with mitochondria (median separation 6.2 nm in 3D studies) which may provide a basis for the recently-discovered role of NAADP in reperfusion-induced cell death. The trigger hypothesis for NAADP action proposes that calcium release from acidic stores subsequently acts to enhance calcium release from the SR. This work provides structural evidence in cardiac myocytes to indicate the formation of microdomains between acidic and SR calcium stores, supporting emerging interpretations of NAADP physiology and pharmacology in heart

    Diritto alla riservatezza e trasparenza: la Corte costituzionale e il "test di proporzionalit\ue0" (nota a Corte costituzionale, 21 febbraio 2019, n. 20)

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    Analizzata la sentenza della Corte costituzionale sul tema del bilanciamento fra i valori costituzionali della riservatezza e della trasparenza, si affronta il tema della necessit\ue0 di conciliare l\u2019esigenza di trasparenza e informazione con quella della riservatezza del personale pubblico. Il tema \ue8 del massimo rilievo se solo si considera che la disciplina legata all\u2019accesso ai dati, informazioni e documenti detenuti dalle amministrazioni svolge una funzione essenziale anche sul piano dell\u2019anticorruzione

    Sex differences in the control of neuronal nitric oxide synthase by GABA-A receptors in the developing rat diencephalon

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    The nitric oxide free radical (NOradical dot), which is synthesized by neuronal nitric oxide synthase (nNOS), is known to play an important morphogenetic role in the developing rat brain. In the cortex, the levels of nNOS are regulated by phosphorylated cAMP response element binding protein (pCREB) downstream of GABA-A receptor activation. During early stages of neonatal development, binding of GABA to its type A receptors leads to depolarization of the neuronal membrane. One of the developmental processes mediated through GABA-A receptors is the sexual differentiation of the brain. In the present work, we investigated the effect of GABA-A receptor activation on nNOS and pCREB immunoreactivity in the developing diencephalon of 5-day-old male and female rats. Our results showed that in the bed nucleus of the stria terminalis activation of GABA-A receptors leads to increased numbers of nNOS, and pCREB as well as nNOS-pCREB doubly immunopositive cells only in the males while in the posterior hypothalamus this effect is observed in both sexes. The GABA-A receptor-mediated increase in nNOS and pCREB is abolished when L-type voltage-gated Ca2+ channels are blocked. These results indicate that the following mechanism could be operating in a gonadal hormone-dependent and brain area-specific manner during neonatal rat brain development: Depolarization following GABA-A receptor activation leads to opening of L-type voltage-gated calcium channels, resulting in an increased Ca2+ influx, which in turn leads to phosphorylation, and thus activation of the transcription factor CREB; the phosphorylated CREB can then induce nNOS. © 2007 Elsevier B.V. All rights reserved
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