65 research outputs found
Instability, growth and economic performance: evidence of 17 Latin American countries 1980-2014
El trabajo estudia el efecto de la inestabilidad econĂłmica sobre el crecimiento en 17 paĂses de LatinoamĂ©rica en el perĂodo 1980-2014 para tres diferentes grupos de crecimiento econĂłmico: bajo, medio y alto. La hipĂłtesis es que una economĂa más inestable, es decir, con mayor inflaciĂłn y volatilidad del producto perjudica a la inversiĂłn y, por tanto, al crecimiento. Para contrastar esta hipĂłtesis se estima un modelo de efectos aleatorios usando un panel de 17 paĂses de AmĂ©rica Latina de un perĂodo de 35 años, en el cual se clasifican los paĂses de acuerdo con el mĂ©todo de clĂşster de k-medianas. Los resultados indican que la inestabilidad afecta negativamente el desempeño econĂłmico de la regiĂłn, en particular en los paĂses de menor crecimiento. Por tanto, en estos casos se recomienda la aplicaciĂłn de polĂticas anticĂclicas y anti-inflacionarias.This paper studies the effect of economic stability on the growth of 17 Latin American countries between 1980-2014 for three different economic growth groups; low, middle and high. The hypothesis is that a more unstable economy, meaning, a larger inflation and product volatility, negatively affects investments, which affects growth. In order to contrast this hypothesis, a random effect model is estimated using a panel of 17 Latin American countries in a 35-year period, in which countries are classified according to the k-median cluster method. Results indicate that instability affects negatively the economic performance of the region, particularly countries with a smaller growth. Because of this, the recommendation for such cases is the application of anti-cyclic and anti-inflationary policies.O trabalho estuda o efeito da instabilidade econĂ´mica sobre o crescimento em 17 paĂses da Latino-amĂ©rica no perĂodo 1980-2014 para trĂŞs diferentes grupos de crescimento econĂ´mico: baixo, mĂ©dio e alto. a hipĂłtese Ă© que uma economia mais instável, ou seja com maior inflação e volatilidade do produto, prejudica ao investimento e por tanto ao crescimento. Para contrastar esta hipĂłtese se estima um modelo de efeitos aleatĂłrios usando um painel de 17 paĂses da AmĂ©rica Latina de um perĂodo de 35 anos, no qual se classificam os paĂses de acordo ao mĂ©todo de clĂşster de k-medianas. Os resultados indicam que a instabilidade afeta negativamente o desempenho econĂ´mico da regiĂŁo, em particular nos paĂses de menor crescimento. Por tanto, nestes casos se recomenda a aplicação de polĂticas anticĂclicas e anti-inflacionárias
Correlations of structural, magnetic, and dielectric properties of undoped and doped CaCu3Ti4O12
The present work reports synthesis, as well as a detailed and careful
characterization of structural, magnetic, and dielectric properties of
differently tempered undoped and doped CaCu3Ti4O12 (CCTO) ceramics. For this
purpose, neutron and x-ray powder diffraction, SQUID measurements, and
dielectric spectroscopy have been performed. Mn-, Fe-, and Ni-doped CCTO
ceramics were investigated in great detail to document the influence of
low-level doping with 3d metals on the antiferromagnetic structure and
dielectric properties. In the light of possible magnetoelectric coupling in
these doped ceramics, the dielectric measurements were also carried out in
external magnetic fields up to 7 T, showing a minor but significant dependence
of the dielectric constant on the applied magnetic field. Undoped CCTO is
well-known for its colossal dielectric constant in a broad frequency and
temperature range. With the present extended characterization of doped as well
as undoped CCTO, we want to address the question why doping with only 1% Mn or
0.5% Fe decreases the room-temperature dielectric constant of CCTO by a factor
of ~100 with a concomitant reduction of the conductivity, whereas 0.5% Ni
doping changes the dielectric properties only slightly. In addition,
diffraction experiments and magnetic investigations were undertaken to check
for possible correlations of the magnitude of the colossal dielectric constants
with structural details or with magnetic properties like the magnetic ordering,
the Curie-Weiss temperatures, or the paramagnetic moment. It is revealed, that
while the magnetic ordering temperature and the effective moment of all
investigated CCTO ceramics are rather similar, there is a dramatic influence of
doping and tempering time on the Curie-Weiss constant.Comment: 10 pages, 11 figure
On the magnetism of Ln{2/3}Cu{3}Ti{4}O{12} (Ln = lanthanide)
The magnetic and thermodynamic properties of the complete
LnCuTiO series were investigated. Here stands for
the lanthanides La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb. %Most
of the compounds were prepared as single phase polycrystalline powder %without
any traces of impurities. Marginal amounts of %impurities were
detected Gd, Er, and Tm. %Significant amounts of impurity phases were
found for Ce and Yb. All the samples investigated crystallize in the
space group with lattice constants that follow the lanthanide
contraction. The lattice constant of the Ce compound reveals the presence of
Ce leading to the composition CeCuTiO. From
magnetic susceptibility and electron-spin resonance experiments it can be
concluded that the copper ions always carry a spin and order
antiferromagnetically close to 25\,K. The Curie-Weiss temperatures can
approximately be calculated assuming a two-sublattice model corresponding to
the copper and lanthanide ions, respectively. It seems that the magnetic
moments of the heavy rare earths are weakly coupled to the copper spins, while
for the light lanthanides no such coupling was found. The moments remain
paramagnetic down to the lowest temperatures, with the exception of the Tm
compound, which indicates enhanced Van-Vleck magnetism due to a non-magnetic
singlet ground state of the crystal-field split manifold. From
specific-heat measurements we accurately determined the antiferromagnetic
ordering temperature and obtained information on the crystal-field states of
the rare-earth ions. The heat-capacity results also revealed the presence of a
small fraction of Ce in a magnetic state.Comment: 10 pages, 10 figure
Randomized, Double-Blind, Placebo-Controlled Phase III Study of Tasquinimod in Men With Metastatic Castration-Resistant Prostate Cancer
PURPOSE: Tasquinimod, a novel oral therapy targeting the tumor microenvironment, significantly improved progression-free survival (PFS) in a randomized, placebo-controlled phase II trial in men with metastatic castration-resistant prostate cancer (mCRPC). This phase III study was conducted to confirm the phase II results and to detect an overall survival (OS) benefit.
PATIENTS AND METHODS: Men with chemotherapy-naĂŻve mCRPC and evidence of bone metastases were assigned (2:1) to receive tasquinimod once per day or placebo until progression or toxicity. The primary end point was radiographic PFS (rPFS; time from random assignment to radiologic progression or death) per Prostate Cancer Working Group 2 criteria and RECIST 1.1. The study had 99.9% power to detect an rPFS hazard ratio (HR) of 0.6 with a two-sided alpha error of .05 and 80% power to detect a target HR of 0.8 for OS, the key secondary end point.
RESULTS: In all, 1,245 patients were randomly assigned to either tasquinimod (n = 832) or placebo (n = 413) between March 2011 and December 2012 at 241 sites in 37 countries. Baseline characteristics were balanced between groups: median age, 71 years; Karnofsky performance status ≥ 90%, 77.3%; and visceral metastases, 21.1%. Estimated median rPFS by central review was 7.0 months (95% CI, 5.8 to 8.2 months) with tasquinimod and 4.4 months (95% CI, 3.5 to 5.5 months) with placebo (HR, 0.64; 95% CI, 0.54 to 0.75; P < .001). Median OS was 21.3 months (95% CI, 19.5 to 23.0 months) with tasquinimod and 24.0 months (95% CI, 21.4 to 26.9 months) with placebo (HR, 1.10; 95% CI, 0.94 to 1.28; P = .25). Grade ≥ 3 adverse events were more frequent with tasquinimod (42.8% v 33.6%), the most common being anemia, fatigue, and cancer pain.
CONCLUSION: In chemotherapy-naĂŻve men with mCRPC, tasquinimod significantly improved rPFS compared with placebo. However, no OS benefit was observed
Colossal dielectric constants in transition-metal oxides
Many transition-metal oxides show very large ("colossal") magnitudes of the
dielectric constant and thus have immense potential for applications in modern
microelectronics and for the development of new capacitance-based
energy-storage devices. In the present work, we thoroughly discuss the
mechanisms that can lead to colossal values of the dielectric constant,
especially emphasising effects generated by external and internal interfaces,
including electronic phase separation. In addition, we provide a detailed
overview and discussion of the dielectric properties of CaCu3Ti4O12 and related
systems, which is today's most investigated material with colossal dielectric
constant. Also a variety of further transition-metal oxides with large
dielectric constants are treated in detail, among them the system La2-xSrxNiO4
where electronic phase separation may play a role in the generation of a
colossal dielectric constant.Comment: 31 pages, 18 figures, submitted to Eur. Phys. J. for publication in
the Special Topics volume "Cooperative Phenomena in Solids: Metal-Insulator
Transitions and Ordering of Microscopic Degrees of Freedom
Finds from Miletus XXX. An Early Archaic Sheet Gold Fragment from Miletus with an Epichoric Inscription
Ein kleines Goldblech aus dem Aphrodite-Heiligtum auf dem Zeytintepe in Milet trägt die Reliefdarstellung einer hockenden Sphinx. Die stilistische Analyse weist auf ein griechisches Werk, das wahrscheinlich in Milet selbst im 3. Viertel des 7. Jhs. v. Chr. entstand. Eine Inschrift am rechten Rand stellt eines der ältesten archaischen Schriftzeugnisse des südwestlichen Kleinasiens dar. Die Schrift lässt sich bisher keiner der in diesem Raum bezeugten Sprachen überzeugend zuweisen. Im Rahmen dieses Beitrags wird der epigraphische Befund möglichst ausführlich dokumentiert. Die Deutung muss den Spezialisten epichorischer Inschriften Kleinasiens überlassen bleiben.A small piece of sheet gold from the sanctuary of Aphrodite on Zeytintepe in Miletus carries a relief depicting a seated sphinx. Stylistic analysis indicates a Greek work that probably originates from Miletus in the 3rd quarter of the 7th century B.C. An inscription at the right-hand edge is one of the oldest Archaic specimens of writing from southwest Asia Minor. It has so far not been possible to ascribe the writing convincingly to any of the languages attested for this region. In this article the epigraphic evidence is documented in as much detail as possible. Interpretation must be left to specialists in the epichoric inscriptions of Asia Minor.
Offrandes de l’époque géométrique et archaïque à l’Héraion de Samos
A toutes les époques, l’homme a développé des signes visibles pour exprimer ses vœux, ses préoccupations et sa gratitude envers la divinité. On peut observer la réalisation de cette attitude, encore aujourd’hui, dans nombre de lieux sacrés du culte chrétien. Tant que la vie humaine était déterminée en grande partie par la religion, ce fait ne suscitait pas des analyses scientifiques. Ce n’est que depuis que la pensée moderne nous a éloignés de ces manifestations d’une religiosité vivante que ..
Etude de la nanostructuration de matériaux énergétiques multi-composants pour application aux poudres propulsives à sensibilités réduites
The PhD thesis presented in this manuscript focused on the elaboration and characterization of propellants with reduced sensitivities. This was accomplished by the use of relatively insensitive energetic materials, in conjunction with the application of the Spray Flash Evaporation (SFE) process. The latter made it possible to obtain nanostructured propellants of ternary composition.The characterization of these propellants by Raman spectroscopy revealed the mechanisms ruling the plasticization of nitrocellulose by the plasticizers used. Scanning electron microscopy analyzes were conducted to determine the particle size of these samples. Their characterization by X-ray diffraction allowed to study their structure and their crystallization. These propellants were shown to be particularly insensitive through analyses by differential scanning calorimetry,pyrotechnic tests in tubes and manometric vessels as well as sensitivity measurements to various types of solicitations.Les travaux de thèse présentés dans ce manuscrit ont porté sur l’élaboration et la caractérisation de poudres propulsives à sensibilités réduites. Ceci a été effectué par l’utilisation de matériaux énergétiques relativement insensibles ainsi que par l’emploi du procédé de Spray Evaporation Flash (SFE). Ce dernier a permis d’obtenir des poudres nanostructurées de composition ternaire. La caractérisation de ces poudres propulsives par spectroscopie Raman a permis de mettre en évidence le mécanisme de plastification de la nitrocellulose par les plastifiants employés. Des analyses de microscopie électronique à balayage ont été menées pour étudier la granulométrie de ces échantillons. Leur caractérisation par diffraction des rayons X a permis d’étudier leur structure et leur cristallisation. Des mesures de calorimétrie différentielle à balayage, des essais de tirs en tubes et en bombe manométrique, ainsi que des mesures de sensibilités à divers types de sollicitations, ont permis de montrer que les poudres obtenues sont particulièrement insensibles
Diffusion acoustique par des coques spheriques a parois minces
SIGLEINIST TD 19579 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
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