Commodity price fluctuations and their impact on monetary and fiscal policies in Western and Central Africa

Commodity prices play an important role in economic developments in most of the 24 Western and Central African (WCA) countries covered in this paper. It is confirmed that in the light of rising commodity prices between 1999 and 2005, net oil exporters recorded strong growth rates while net oil-importing countries – albeit benefiting from increases in their major non-oil commodity export prices – displayed somewhat lower growth. For most WCA economies, inflation rates appear less affected by commodity price changes and more determined by exchange rate regimes as well as monetary and fiscal policies. While passthrough effects from international to domestic energy prices were significant, notably in oilimporting countries, second-round effects on overall prices seem limited. Governments of oil-rich countries reacted prudently to windfall revenues, partly running sizable fiscal surpluses. A favourable supply response to rising spending as well as sterilisation efforts and increasing money demand also helped to dampen inflationary pressures. However, substantial excess reserves of commercial banks reflect challenges in financial sector developments and the effectiveness of monetary policy in many WCA countries. Given currently widelyused fixed exchange rate regimes, fiscal policy will continue to carry the main burden of macroeconomic adjustment and of sustaining non-inflationary growth, which remains the key policy challenge facing WCA authorities.

Estimação da posição do teclado em dispositivos móveis a partir de vídeos capturados por câmeras de vigilância

Trabalho de Conclusão de Curso (graduação)—Universidade de Brasília, Instituto de Ciências Exatas, Departamento de Ciência da Computação, 2016.O presente trabalho tem como objetivo a utilização de técnicas de processamento de imagens e vídeos para demonstrar a vulnerabilidade existente em sistemas de segurança baseados no uso de códigos PINs (Personal Identification Number) em ambientes vigiados por câmeras. Para exemplificar essa fragilidade do sistema de autenticação, um experimento foi desenvolvido em que várias pessoas foram filmadas ao inserirem alguns PINS em teclados diferentes. Um algoritmo foi criado para detectar a localização aproximada do teclado, aplicando técnicas de estimação de movimento e operações morfológicas, a fim de demonstrar a viabilidade desse modelo de ataque.The main goal of the following paper is to demonstrate the existing vulnerability in PIN code based security systems present in locations under surveillance, utilizing techniques in image and video processing. To exemplify the fragility of this authentication system, an experiment was conducted in which several people were filmed as they inserted a couple of PIN codes into different keypads. An algorithm was created to detect the approximate location of the keypad, by applying motion estimation techniques and morphological operations, to demonstrate the viability of this attack model

Financial stability challenges in candidate countries - managing the transition to deeper and more market-oriented financial systems.

This paper reviews financial stability challenges in the EU candidate countries Croatia, Turkey and the former Yugoslav Republic of Macedonia. It examines the fi nancial sectors in these three economies, which, while at very different stages of development and embedded in quite diverse economic settings, are all in a process of rapid financial deepening. This manifests itself most clearly in the rapid pace of growth in credit to the private sector. This process of financial deepening is largely a natural and welcome catching-up phenomenon, but it has also increased the credit risks borne by the banking sectors in the three economies. These credit risks are compounded by the widespread use of foreign currency-denominated or -indexed loans, leaving unhedged bank customers exposed to potential swings in exchange rates or foreign interest rates. Moreover, these financial risks form part of a broader nexus of vulnerabilities in the economies concerned, in particular the external vulnerabilities arising from increasing private sector external indebtedness. That said, the paper also fi nds that the authorities in the three countries have taken several policy actions to reduce these fi nancial and external vulnerabilities and to strengthen the resilience of the financial sectors. JEL Classification: F32, F41, G21, G28.Europe, banking sector, vulnerability indicators, capital inflows, emerging markets.

Analysis of a four-mirror cavity enhanced Michelson interferometer

We investigate the shot noise limited sensitivity of a four-mirror cavity enhanced Michelson interferometer. The intention of this interferometer topology is the reduction of thermal lensing and the impact of the interferometers contrast although transmissive optics are used with high circulating powers. The analytical expressions describing the light fields and the frequency response are derived. Although the parameter space has 11 dimensions, a detailed analysis of the resonance feature gives boundary conditions allowing systematic parameter studies

A VLA search for young protostars embedded in dense cores

Four dense cores, L1582A, L1689A, B133 and B68, classified as prestellar in terms of the absence of detectable NIR emission, are observed at radio wavelengths to investigate whether they nurture very young protostars. No definite young protostars were discovered in any of the four cores observed. A few radio sources were discovered close to the observed cores, but these are most likely extragalactic sources or YSOs unrelated to the cores observed. In L1582A we discovered a weak radio source near the centre of the core with radio characteristics and offset from the peak of the submillimeter emission similar to that of the newly discovered protostar in the core L1014, indicating a possible protostellar nature for this source. This needs to be confirmed with near- and/or mid-infrared observations (e.g. with Spitzer). Hence based on the current observations we are unable to confirm unequivocally that L1582A is starless. In L1689A a possible 4.5-sigma radio source was discovered at the centre of the core, but needs to be confirmed with future observations. In B133 a weak radio source, possibly a protostar, was discovered at the edge of the core on a local peak of the core submm emission, but no source was detected at the centre of the core. Thus, B133 is probably starless, but may have a protostar at its edge. In B68 no radio sources were discovered inside or at the edge of the core, and thus B68 is indeed starless. Four more radio sources with spectral indices characteristic of young protostars were discovered outside the cores but within the extended clouds in which these cores reside. Conclusions: We conclude that the number of cores misclassified as prestellar is probably very small and does not significantly alter the estimated lifetime of the prestellar phase.Comment: Accepted by A&

Mega-analysis methods in ENIGMA : the experience of the generalized anxiety disorder working group

The ENIGMA group on Generalized Anxiety Disorder (ENIGMA-Anxiety/GAD) is part of a broader effort to investigate anxiety disorders using imaging and genetic data across multiple sites worldwide. The group is actively conducting a mega-analysis of a large number of brain structural scans. In this process, the group was confronted with many methodological challenges related to study planning and implementation, between-country transfer of subject-level data, quality control of a considerable amount of imaging data, and choices related to statistical methods and efficient use of resources. This report summarizes the background information and rationale for the various methodological decisions, as well as the approach taken to implement them. The goal is to document the approach and help guide other research groups working with large brain imaging data sets as they develop their own analytic pipelines for mega-analyses

QUALIDADE AMBIENTAL EM FRAGMENTOS DE EUCALYPTUS SPP. DETERMINADA A PARTIR DE PROCESSOS FUNCIONAIS DA SERAPILHEIRA

O objetivo do estudo foi compreender a influência do cultivo de Eucalyptus spp., sobre a qualidade do ambiente em que está inserido. Para tal, foram utilizadas três áreas amostrais (eucaliptais) e uma área controle, composta por vegetação heterogênea. Foram realizadas, mensurações da perda de massa da serapilheira foliar, testes de capacidade de retenção hídrica (CRH), e, mensuração da concentração de macronutrientes e das frações orgânicas (lignina, celulose e polifenóis) na serapilheira. As amostras de serapilheira da área controle apresentaram coeficiente de decomposição (k) (0,78; 0,82; 0,87) significativamente maiores que as das amostras de Eucalyptus spp. (0,51; 0,52; 0,55). Para a CRH, as amostras provenientes da área controle apontaram valores entre 161% e 339%, com valor médio de 260%. Que foram significativamente maiores que os das áreas de eucaliptais, que variaram entre 72% e 156%, com valor médio igual a 112%. Quanto ao teor dos macronutrientes, para a concentração de N e Mg na serapilheira, as amostras coletadas na área controle apresentaram valores médios significativamente maiores que as amostras das áreas de eucaliptais. Quanto aos teores de lignina e polifenóis, as amostras coletadas nas áreas de eucaliptais apontaram valores significativamente maiores que os apresentados pela área controle. Os resultados obtidos, apontaram para forte correlação estatística entre as concentrações de N, Mg, lignina e polifenóis, no material foliar amostrado, taxas de decomposição e capacidade de retenção hídrica. A decomposição de Eucalyptus spp. apresentou lenta decomposição, fortemente ligada à sua composição química, o que dificulta a ação dos agentes decompositores

CARACTERÍSTICAS FÍSICAS E QUÍMICAS DO TOPO DO SOLO EM ÁREAS DE PLANTAÇÕES DE EUCALYPTUS SPP. E MATA ATLÂNTICA NO CAMPO DAS VERTENTES – MG

Intense anthropic actions have an impact on ecosystems. Among the activities developed, the monoculture is included, which, under the perspective of geoecology, acts as a factor in reducing biodiversity the analyzes related to the responsible processes on the functioning of ecosystems, appear as an alternative to assess the levels of environmental disturbances. Having seen the great importance of the processes that occur of the constant interaction between soil and litter, for ecosystems, this study aimed to measure the quality of the soil in areas with different vegetation coverings, studying the influence of the litter deposited in that areas, on the quality of topsoil (0 - 40 cm). To this, analyzes were related to the chemical and physical characteristics of the topsoils in the sample areas. The collections of the samples were realized in three areas of eucalyptus plantations and a control area composed of heterogeneous vegetation, located in an area of Seasonal Semideciduous Forest. The top of the soils in the sample areas are acidic, dystrophic with values for the sum of exchangeable bases (SB) below 1.2 cmolc / dm³, and the base saturation index (V) less than 25%. The soils of the control area presented high saturation of aluminum (m>50%), the feature of the alic soils. While the soils of the eucalyptus areas presented low in aluminum saturation (m<50%), characteristic of acric soils. The soils sampled have a low capacity of Effective Cation Exchange, CTC (t). The soils in the control area have a lower P retention capacity, showing a high value for the rate of phosphorus remaining in the soil (P-rem). As for the physical characteristics of the topsoil, the control area presented sandy texture, and eucalyptus areas, clay texture. The control area showed a predominance of soil aggregates greater than 2 mm <50%), characteristic of acric soils. The soils sampled have a low capacity of Effective Cation Exchange, CTC (t). The soils in the control area have a lower P retention capacity, showing a high value for the rate of phosphorus remaining in the soil (P-rem). As for the physical characteristics of the topsoil, the control area presented sandy texture, and eucalyptus areas, clay texture. The control area showed a predominance of soil aggregates greater than 2 mm (Student's t-test, p< 0.05). In general, the chemical and physical attributes of the topsoils found in this study did not differ much between the studied areas, this fact can be explained by the soil depth sampled, in which the influence of the litter is no longer as great as in the first 5 -10 centimeters from the ground.As intensas ações antrópicas causam impactos negativos nos ecossistemas. Dentre as atividades desenvolvidas, inclui-se a monocultura, que sob a ótica da geoecologia, age como um fator de redução da biodiversidade. Neste contexto, as análises relacionadas aos processos responsáveis sobre o funcionamento dos ecossistemas, surgem como alternativa para avaliar os níveis de perturbações ambientais. Haja visto a grande importância dos processos que ocorrem durante a constante interação entre solo e serapilheira, para os ecossistemas, este estudo pretendeu mensurar a qualidade do solo em áreas que apresentam distintas coberturas vegetais, visando mensurar a influência da serapilheira depositadas nestas áreas, sobre a qualidade do topo do solo (0 – 40 cm). Para tal, foram realizadas análises relacionadas às características químicas e físicas do topo dos solos das áreas amostrais. As coletas das amostras foram realizadas em três áreas de plantações de eucaliptais e uma área controle composta por vegetação heterogênea, localizada em área de Floresta Estacional Semidecidual. O topo dos solos das áreas amostrais são ácidos, distróficos com valores para soma de bases trocáveis (SB) abaixo de 1,2 cmolc/dm³, e o índice de saturação de bases (V) menor que 25%. Os solos da área controle, apresentaram alta saturação de alumínio (m > 50%), característica de solos álicos. Enquanto os solos das áreas de eucaliptais apresentaram baixa saturação em alumínio (m < 50%), característica de solos ácricos. Os solos amostrados apresentaram baixa Capacidade de Troca Catiônica Efetiva, CTC (t). Os solos da área controle apresentaram menor capacidade de retenção de P, demonstrando alto valor para a taxa de fósforo remanescente no solo (P-rem). Quanto às caraterísticas físicas do topo do solo, as amostras da área controle apresentaram textura arenosa, e das áreas eucaliptais, textura argilosa. A área controle apresentou predominância de agregados dos solos maiores que 2 mm (Teste t- de Student, p < 0,05). No geral, os atributos químicos e físicos do topo dos solos encontrados neste estudo não se diferenciaram muito entre as áreas estudadas, tal fato pode ser explicado pela profundidade de solo amostrada, na qual a influência da serapilheira já não seja tão grande como nos primeiros 5-10 centímetros dos solos

Validation of the near infrared spectroscopy method for determining soil organic carbon by employing a proficiency assay for fertility laboratories

Current research indicates that near infrared (NIR) spectroscopy is the most promising alternative technique for the determination of soil organic carbon (SOC) in laboratories worldwide and that it may serve as a total or partial replacement for the tradi243293303The authors acknowledge Embrapa for financial support (MP3 03.12.03.010.00.00

Impact of Protostellar Outflow on Star Formation: Effects of Initial Cloud Mass

Star formation efficiency controlled by the protostellar outflow in a single cloud core is investigated by three-dimensional resistive MHD simulations. Starting from the prestellar cloud core, the star formation process is calculated until the end of the main accretion phase. In the calculations, the mass of the prestellar cloud is parameterized. During the star formation, the protostellar outflow is driven by the circumstellar disk. The outflow extends also in the transverse direction until its width becomes comparable to the initial cloud scale, and thus, the outflow has a wide opening angle of >40 degrees. As a result, the protostellar outflow sweeps up a large fraction of the infalling material and ejects it into the interstellar space. The outflow can eject at most over half of the host cloud mass, significantly decreasing star formation efficiency. The outflow power is stronger in clouds with a greater initial mass. Thus, the protostellar outflow effectively suppresses star formation efficiency in a massive cloud. The outflow weakens significantly and disappears in several free-fall timescales of the initial cloud after the cloud begins to collapse. The natal prestellar core influences the lifetime and size of the outflow. At the end of the main accretion phase, a massive circumstellar disk comparable in mass to the protostar remains. Calculations show that typically, ~30% of the initial cloud mass is converted into the protostar and ~20% remains in the circumstellar disk, while ~40% is ejected into the interstellar space by the protostellar outflow. Therefore, a single cloud core typically has a star formation efficiency of 30-50%.Comment: 43 pages, 14 figures, Submitted to MNRAS. For high resolution figures see http://jupiter.geo.kyushu-u.ac.jp/machida/arxiv/sfe.pd