On the role of convection and turbulence for tropospheric ozone and its precursors

An overview of the work with the main conclusions is presented here. The conclusions are formulated as answers to the questions formulated in the introduction : 1. How large is the sensitivity of the (model simulated) distribution of ozone and nitrogen oxides on (the) convection (parameterisation)? This question has been addressed in Chapter 2. We have performed model simulations with the TM3 model for the years 1991 until 1996. We have used two di??erent data sets for describing the convective transport : archived convective mass uxes during the ERA-40 project, and o??-line diagnosed convective mass uxes. Comparison with observations of 222Rn in the upper troposphere showed that the archived convective mass uxes perform better. Large di??erences in tracer concentrations resulted from switching the convective data sets. In the archived case, NOx concentrations were found to be larger in the middle troposphere and substantially smaller in the upper troposphere and lower stratosphere than in the diagnosed case. For ozone rather strong di??erences were found, with for the archived case enhanced concentrations in the middle troposphere and lower values in the upper troposphere and lower stratosphere. In summary, the modelled NOx and O3 distributions for the two convective data sets di??er substantially. This large sensitivity of the model results, also shows that convection is a key process in the distribution for ozone and its precursors. 2. What requirements should be ful??lled by di??usive transport parameterisations in order to simulate the diurnal cycle in trace gas concentrations? This question has been addressed in Chapter 3. We have performed model simulations with the TM3 model for the years 1959 until 1962, and for 1993, using 4 di??erent sets of vertical di??usion coe??cients. We have compared the model simulated 222Rn concentration with observations at four surface stations. We have also compared model simulated and observed atmospheric boundary layer heights at 2 northern hemispheric mid-latitude locations. Using a time resolution of 3 hours for the di??usion coe??cients, resulted in a reasonable representation of the daily cycle of the 222Rn concentration. Because the daily evolution of the di??usion coe??cient is characterized by strong increases and decreases in the turbulence, instantaneous di??usion coe??- cients were better suited to simulate the observed 222Rn than averaged/accumulated ones. The comparison has also shown that non-local di??usion schemes perform better than local di??usion schemes. The 222Rn concentration at one of the surface stations which lies on top of a hill, was not well represented. Because of the rather coarse model resolution at the top of the boundary layer, strong gradients that may exist there, are not represented accurately by the model. Therefore an increased model resolution might be necessary to simulate well the daily cycle higher up in the ABL or lower free troposphere. 3. How large are the di??erences in concentrations between simulations with archived and o??-line diagnosed physical parameterisations? This question refers to Chapters 2 and 3. In these chapters, we compared the e??ect of using archived data from an NWP model for describing subgrid-scale transport instead of o??-line diagnosis of subgrid-scale transport. Rasch et al. [1997] also studied this e??ect and suggested that using 6 hourly diagnosed meteorological ??elds would be su??cient for a reasonable representation. We must admit that our comparison is slightly biased. The parameterisation for the o??-line diagnosis of the transport is not completely identical to the parameterisation applied in the NWP. It re ects however the realistic situation where changes in NWPs are incorporated with a delay in the o??-line parameterisations in CTMs. Although there are some apparent di??erences between the parameterisations, some of the o??ine parameterisations are quite well able to reproduce the archived ??elds : for instance the pro??les of convective mass uxes, as well as the pro??les of the di??usion coe??cients. The di??erences in the concentrations of tracers such as 222Rn, NOx and O3 are related to their lifetime and to the magnitude of the gradient in the tracer concentration at the location where the di??usive or convective processes are active. Due to the sensitivity to convection, in the upper troposphere the di??erence in zonal mean concentration for 222Rn, and NOx amounted to more than 50%, while for ozone they were still up to 20%. Also in the middle troposphere, the di??erences were substantial, but mainly so in the tropics. The e??ect of using di??erent turbulent transport data on the concentration of 222Rn was smaller. In the middle and upper troposphere, zonal mean di??erences in 222Rn concentration were less than 10%. However, in the ABL, instantaneous di??erences amounted locally up to 20%. 4. How do the results of di??erent parameterisations of nitrogen oxide production by lightning compare? This question was addressed in Chapter 4. The current standard TM lightning parameterisation [Meijer et al., 2001] has been compared with the lightning parameterisation of Grewe et al. [2001]. The implementation of the latter parameterisation, which depends non-linearly on the updraft velocity, appeared to be very sensitive to updraft intensity in the TM model. Therefore a slightly modi??ed formulation has been applied, which mitigates the over-intense events. We found signi??cant di??erences in the zonal distribution and seasonal cycle between the di??erent parameterisations. The comparison with airborne observations from measurement campaigns did not allow to decide which parameterisation performs best. 5. What is the e??ect of an explicit description of the e??ect of convective redistribution on the vertical distribution of lightning produced NOx? This question has also been addressed in Chapter 4. With an explicit description of the vertical redistribution of LNOx by convection, we were able to reproduce the C-shaped emission pro??les suggested by Pickering et al. [1998]. Large di??erences were again found between the use of archived and o??-line diagnosed convective mass uxes. The di??erence in convective mass ux pro??les resulted in characteristic features. The o??-line diagnosed mass uxes have organized detrainment only close to the top of the updraft. This results in rather thin out ow layers. The archived convection, having organized detrainment over a somewhat larger extent of the cloud, showed thicker out ow layers, which is probably more realistic. The downdrafts were however not able to realise enough explicit downward transport to the lowest model layers. The comparison with aircraft measurements showed some improvement for the ights where the model in previous versions exhibited an underestimate of the NOx concentrations. It can be concluded that the convective mass uxes are a promising tool to improve the vertical distribution of lightning emissions

Global and Domestic Factors of Financial Crises in Emerging Economies: Lessons from the East Asian Episodes (1997-1999)

This paper suggests that a new approach is needed in order to identify the causes of the East Asian financial crises and that this new approach might be fruitful in reassessing the analyses and theories of financial crises in emerging economies. The first part of the paper presents a new empirical analysis of the state of fundamentals in East Asia before the crises. It suggests that the relevant fundamentals were both non-conventional and "intermediate" (or not "bad" enough to trigger the crises by themselves). Fundamentals were also different from those preceding previous turmoils in the 1990s, such as the ERM crisis in 1992-1993 and the Mexican crisis in 1994-1995. The second part highlights that existing theoretical models of currency crises miss some important points. Even second generation models, which stress self-fulfilling expectations and which acknowledge that crises might appear against the backdrop of non-conventional and intermediate fundamentals, explain only the role of fundamentals in relation to private expectations. But they do not explain how can it be that a shift in private agents' expectations turns out into a financial crisis. The third part suggests that the current process of globalization exacerbates failures in international capital markets and impinges upon capital flows and the pace and order of financial liberalization in emerging economies, increasing therefore uncertainty and rendering large domestic vulnerabilities. It also highlights how financial globalization was related to the East Asian crises. The main conclusion is that intermediate non-conventional fundamentals, shifts in private agents' expectations and financial globalization were arguably the main factors of the East Asian crisis. Therefore, in order to prevent future financial crises, governments in emerging economies should try to exit crises zones through improving their fundamentals, to proceed carefully with financial liberalization, to implement some kind of capital controls and to urge for the establishment of a new global financial architecture.

Changes in haematological parameters during a summer expedition in Antarctica

The aim of this study was to examine the effect of extreme climatic conditions and a long stay in isolation on levels of three haematological parameters in the polar expedition participants. This article describes changes in erythrocyte count, hemoglobin and transferrin levels measured on the 9th Czech Antarctic Scientific Expedition during the period of the Antarctic summer. A total of 15 sera samples were collected shortly before the expedition, the second sampling was performed halfway through the stay and the third at the very end of the expedition stationed at the Czech Research Station of J. G. Mendel. The erythrocyte count and the levels of transferrin were significantly increased in between all three sample collections (with p-value < 0.01). A statistically significant increase in hemoglobin levels was only detected between the first and the final sampling (

Some of the metabolic changes in expedition members caused by diet and activities performed during a stay at the Czech Antarc-tic base (Short Communication)

The aim of this study was to evaluate the effect of food intake, extreme climatic and other environmental conditions on metabolic parameters in serum in participants of the 9th Czech Antarctic Scientific Expedition, January – February 2015 (8 weeks). The studied parameters included the level of total cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, uric acid and type of diet. The energy intake, amount of protein in food during the stay were analysed. The values of the above-specified parame-ters were compared with the answers of respondents to questions about food intake served during the expedition and analysed by the (ANOVA) Hartley F, Cochran C, Barttlet Chi test. A total of 45 sera samples were collected during 3 series of sampling. The first one was a pre-departure sampling, the second was taken after the first 2 weeks of the stay in Antarctica, and the third one during the last 2 weeks of the stay). Statisti-cally significant decrease in uric acid and HDL cholesterol in sera was observed during the stay. For this purpose, Student´s paired t-test was used. Scheffe test revealed significant differences in levels of HDL between categories of expeditioners who ate significantly larger amount of protein and equal amount of proteins after 44 days of expedition. In this paper, we discuss the total cholesterol (HDL, LDL), which can lead to dietary problems under stress condition in the Czech Antarctic base

Changes in immunological and physiological parameters in urine duringAntarctic Scientific Expedition( Short Communication )

The aim of this study was to examine the effect of extreme climatic conditions on certain immunological and physiological parameters in urine in participants of the 9th Czech Antarctic Scientific Expedition, January – February 2015. The studied parameters were pH, number of leukocytes in 1 µl urine and the amount of proteins, nitrites, blood and haemoglobin in urine. A total of 45 urine samples were collected during 3 series of sampling (first pre-departure, second during the first 2 weeks of the stay in Antarctica, and third in the last 2 weeks of the stay). Paired t-test was used for comparison of the data from the Czech Republic and the Antarctica. We have found statistically significant decreases in pH and in the number of leukocytes in urine during the stay in Antarctica. The other parameters showed no changes. We conclude that several factors of the Antarctic environment (with lack of stress, pathogenic microorganisms and pollutants) may have positive effects on certain aspects of human health, and discuss the likely causes and mechanisms

Global surface temperature time series characteristics for the earth, in relation to CO2 perturbations

Összefoglalás - A tanulmány célja a globális felszínhőmérséklet idősor néhány statisztikai jellemzőjének tanulmá- nyozása. A lineársi trendanalízis nem mutatott ki hosszú tartamú szignifikáns trendeket. Az esetleges rövid tartamú (legfeljebb hatelemű) trendek a legnagyobb gyakorisággal a D(QTH, QTM) globális felszínhőmérséklet differencia idősor középső harmadában fordulnak elő. A vizsgált idősorra alkalmazzuk a Makra-tesztet, mely a kétmintás próba egy új interpretációja. A próba alapkérdése: kimutatható-e szignifikáns különbség a vizsgált idő- sor egy tetszőleges részmintájának, illetve a teljes idősornak az átlagai között. A próba alkalmas arra, hogy szignifikáns töréseket mutassunk ki az idősorban, meghatározva annak erősségét, hosszát és tartamát, azaz kezdő és záró időpontját. A Makra-próba segítségével meghatároztuk a D(QTH, QTM) globális felszínhőmérséklet differencia idősor szignifikáns részperiódusait. Két szignifikáns részperiódust mutattunk ki: Pozitív törést 1861-1900 között, míg negatív törést 1881-1958 között tapasztaltunk. További célunk az volt, hogy tanulmányozzuk a megnövekedett COj szint hatását a globális felszínhőmérséklet változásaira. A D(QTH, QTM) idősor legjobb görbeillesztései az adatsor varianciájának (teljes négyzetes hiba = total squared error) jelentős részét megmagyarárzzák: R2 > 80 %; RMSE (becsült szórás) < 0.5. Az RMSE értéke igen hasonló a referencia szimulációra kapott RMSE értékhez. Az adatsorhoz illesztett görbék futása az időszak elején növekvő, majd 10-15 éves futást követően eléri maximumát, s később fokozatosan csökken. Ugyanakkor az illesztett görbék számos esetben emelkedő tendenciát jeleznek a vizsgált 100 éves periódus végén, mely meglehetősen leronthatja a hosszútávú előrejelzéseket. Summary - The aim of the study was to analyse some statistical characteristics of the global surface temperature time series. Linear trend analysis did not reveal any significant long-range trends. Significant sporadic short term trends (with not more than 6 elements) can only be observed with higher frequency in the middle third of the D(QTH, QTM) temperature difference times. The Makra-test, as a new interpretation of the two-sample test, was also applied to the global surface temperature time series. The basic question of this test is whether or not a significant difference can be found between the mean of an arbitrary sub-sample of a given time series and that of the whole series. This test is suitable to detect breaks in the data set, along with their strength, length and time interval, namely their starting and ending date. With the help of the Makra-test two significantly different subperiods in the global temperature difference time series of D(QTH, QTM) were detected. In the here-mentioned data set a significant positive break were found between 1861-1900 and a significant negative break relating to the term around 1881-1958. A further aim was to study the effect of the increased CO2 level 01. the changes of the global temperature. The curves best fitting to the D(QTH, QTM) global surface temperature difference time series explain changes (total squared error) of the data set in fairly high ratios. The value of the R-square generally exceeds 80 %. The estimated standard deviations (RMSE) are rather low, mostly below 0.5. These RMSE values are very similar to those of standard deviation in the reference simulation. The fitted curves adjusted to the data show an increasing tendency in the first period; then, after 10-15 years run reaches its maximum and later is gradually decreasing. However, the fitted curves in several cases indicate slight increasing tendencies at the end of the 100-year period, which may rather ruin long-range forecasts

Etirement d'implusions courtes avec des réseaux de Bragg fibres pour les chaines lasers de forte puissance

Le développement de sources lasers Pétawatt nécessite l’utilisation de la méthode d’amplification par dérive de fréquences (Chirped Pulse Amplification : CPA). Afin de limiter les effets non linéaires, l’impulsion courte de départ doit être étirée temporellement d’un facteur de l’ordre de 104-105. Dans de telles conditions, l’encombrement des étireurs standards à réseaux de diffraction est rapidement un problème. Dans cette optique, nous avons étudié les Réseaux de Bragg Fibrés (RBF) comme solution alternative. Nous avons d’abord effectué une modélisation complète en utilisant la théorie des ondes couplées. Les propriétés générales de ce composant pour l’étirement d’impulsions courtes ont pu ainsi être étudiées. Un algorithme de calcul inverse a été utilisé pour dimensionner des RBF simulant la réponse spectrale d’un étireur standard à réseaux de diffraction. Des RBF de ce type et linéairement chirpés ont été étudiés expérimentalement. Nous avons d’abord caractérisé l’impulsion étirée. La mesure précise du profil temporel par corrélation croisée a mise en évidence des différences entre RBF réel et idéal. Nous avons également mesuré la distribution en fréquences de l’impulsion chirpée (délai de groupe). Nous avons démontré un bon accord avec la loi de phase attendue pour un RBF idéal. La suite de notre étude expérimentale a concerné la recompression de l’impulsion étirée avec un RBF. Pour cela, nous avons utilisé un compresseur standard à réseaux de diffraction. L’impulsion recomprimée a été complètement caractérisée. Pour une impulsion de durée initiale de 280 fs à 1053 nm, un RBF de 28 cm a permis de l’étirer à 1 ns; la durée de l’impulsion recomprimée a été mesuréeà une valeur inférieure à 300 fs. Son contraste était de l’ordre de 10-1. Nous avons ainsi démontré pour la première fois la réalisation expérimentale d’un système hybride constitué d’un RBF comme allongeur et d’un compresseur de Treacy pour la recompression.Chirped pulse amplification (CPA) is necessary for the design of Petawatt class laser. To reduce non linear effects, the initial short pulse must be temporally stretched with a factor around 104-105. In this case, the size of standard bulk diffraction gratings based stretchers becomes rapidly cumbersome. As an alternative solution, we have studied Fiber Bragg gratings (FBG). We first developed a complete model using coupled-mode theory. In this way, main properties of this component for short pulse stretching were studied. To determine a FBG that simulate the spectral response of a standard bulk diffraction gratings based stretcher, we used an inverse algorithm. FBG of this kind and linearly chirped FBG were then experimentally studied. We first characterized the stretched pulse. The precise temporal profile measurement with a cross correlation scheme evidenced differences between real and ideal FBG. We have also measured the chirped pulse frequencies distribution (group delay). We found a good agreement with the ideal FBG phase law. The study of the FBG stretched pulse recompression followed. To do this, we used a standard bulk diffraction gratings based compressor. The compressed pulse was entirely characterized. For an initial pulse with a duration of 280 fs and a central wavelength of 1053 nm, a 28 cm long FBG allowed to stretch the short pulse to a duration of 1 ns; the compressed pulse duration was found to be lower than 300 fs. Its contrast was around 10-1. We have therefore experimentally demonstrated for the first time an hybrid association of a FBG as a stretcher and a standard Treacy compressor

TEORIA DAS JANELAS QUEBRADAS: UMA REFLEXÃO NO ORDENAMENTO JURÍDICO BRASILEIRO

This work brings a reflection on the theory of broken windows, seeing its applicability in the Brazilian legal system, given the high crime rate, which generates fear and insecurity. The hypothetical-deductive method was used in the methodology, analyzing from the general to the particular. The institute of criminology will be approached in a succinct manner, pointing out its concept and purposes, as well as in what differs from criminal law. After the brief introduction, the theory of broken windows will be discussed in order to understand it, emphasizing its origin and a parallel of its application in relation to disorder and criminality. We conclude the present article, demonstrating the solidification of the applicability of broken window theory in our Brazilian legal system.Este trabalho traz uma reflexão sobre a teoria das janelas quebradas, vislumbrando sua aplicabilidade no ordenamento jurídico brasileiro, haja vista a alta taxa de criminalidade existente, geradora de temor e insegurança. Utilizou-se, na metodologia, o método hipotético-dedutivo, analisando-se do geral para o particular. Abordar-se-á o instituto da criminologia, de forma sucinta, apontando seu conceito e finalidades, bem como no que se difere do direito penal.&nbsp; Feito o breve introito, a teoria das janelas quebradas será discutida a fim de compreendê-la, enfatizando sua origem e um paralelo de sua aplicação com relação entre a desordem e a criminalidade. Conclui-se o presente artigo, demonstrando a solidificação da aplicabilidade da teoria das janelas quebradas em nosso ordenamento jurídico brasileiro.&nbsp

Morphological and electric characterizations of a nanometric materialα-CuMoO4for photovoltaic application

The work presented in this publication concerns the elaboration by soft chemistry and the structural, morphological and physical characterizations of semiconductors with metallic Oxides CuMoO4. Particularly, we study the caking of powders of molybdate of copper: conventional sintering and Spark Plasma Sintering (SPS). The characterization by X-rays diffraction analyses (DRX) and scanning electronic microscopy (SEM) show that the ceramic obtained by SPS at 300°C for 5 min hasa densificationof 98.0 %, superior to that of the ceramic sintered in a conventional way (94.8 %), with a grainsize (0.2μm) significantlylower than thatobtained by conventional sintering(2.0 μm).The study of the electric properties by the method of the current-voltage measurements (I-V) of the nondoped ceramic CuMoO4showsonone hand, the semiconductor character of the material and on the other hand, a clear improvement of the thermal activationof the carriers in the case of the ceramic obtained by SPS at 300°C. The width of the forbidden gap (Eg) deducted from these measurements is 1.8 ± 0.1 eV