473 research outputs found
The Separation of Powers, Role of the Press and the Emergence of Online Media in China and Taiwan
Despite sharing a common culture over thousands of years, the modern stance of the Chinese and Taiwanese governments relating to the separation of powers and human rights has taken a drastically different path over the past seven decades. This paper begins with a brief introduction to traditional Chinese jurisprudence and how it has been shaped in recent times by the emergence of Western legal principles.It further examines the correlation between the separation of powers and the diversity of political discussion and level of regulation in the media of the People's Republic of China (‘PRC' or ‘China') and the Taiwanese Republic of China (‘ROC' or ‘Taiwan'), and how the constitutional and legislative provisions of each address these concepts and how they reflect International treaties adopted by each government. The emergence of online media to further demonstrate the different stances taken by the PRC and ROC on the adoption of these Western principles is analysed. Finally, the paper will examine the International criticisms the PRC and ROC face for their practices regarding media censorship. The paper suggests that maintaining a separation of powers is crucial in order to uphold a free, independent press
Experimental investigation into lunar melt density and compressibility : the role of titanium
This study focuses on determining the density and compressibility of four lunar picritic glasses as a function of TiO2 content from 0-11 GPa and 1748-2473 K (1475-2200°C). These glasses are hypothesized to have quenched rapidly as glass beads during lunar fire fountain eruptions. The lunar glass beads have distinctive colors that correspond to TiO2 content. The glasses of interest for this study are the Apollo 15 green glass Type C (A15C) which has a TiO2 content of 0.26 wt%, the Apollo 14 yellow glass (A14Y) which has a TiO2 content of 4.58 wt%, the Apollo 17 orange glass 74220-type (A17O) which has a TiO2 content of 9.12 wt%, and the Apollo 14 black glass (A14B) which has the highest TiO2 content with 16.40 wt%. These glasses are believed to represent primary, unfractionated melts making them excellent candidates for experimental studies into lunar basalt density and eruptability during partial melting of the lunar mantle. We performed sink-float experiments on these lunar glass compositions using a piston-cylinder apparatus (P \u3c 2 GPa) and Walker-style multi-anvil device (P \u3e 2 GPa) in order to bracket the density of these melts. We report new sink-float data for A15C, A14Y, and A17O. We find that with increasing pressure, the melts with less TiO2 are more compressible than high TiO2 melts. This causes the melt with the most TiO2 (A14B) to be the least dense at higher pressures, a complete reversal of what is seen at lower pressures. This change in density and compressibility is attributed to the change from [IV]Ti4+ to [VI]Ti4+ in the melt structure for melts with high TiO2 contents. We have identified density crossovers between these melts and their equilibrium olivines and pyroxenes, and show that these glasses, with the exception of A17O, should be able to rise to the surface as a result of buoyancy forces alone. For the eruption of A17O, we must call upon the rising diapir model of Hess (1991) to explain its eruptability
Experimental Investigation into the Thermal and Magmatic Evolution of Mercury
During the time that the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft was in orbit around the innermost planet, new and exciting results regarding the planets structure, chemical makeup, and diverse surface were revealed, confirming that Mercury is a geochemical endmember among the terrestrial planets. Data from this mission, more specifically data from the X-Ray Spectrometer and Gamma-Ray Spectrometer onboard MESSENGER, has been used to provide insight into the thermal and magmatic evolution of Mercury. This dissertation consists of five chapters that, as a whole, have substantially increased our knowledge about Mercury through a high pressure and high temperature experimental investigation. First, we identified nine distinct geochemical regions that have characteristic major element compositions. We computed silicate and sulfide mineralogy of these regions and petrologically classified them according to IUGS specifications. The diversity of the rocks and minerals on Mercury was then compared to other planetary bodies revealing the wide range in diversity of the mercurian surface. Second, we conducted sink-float experiments on a melt composition similar to the composition of the largest volcanic field on the planet to provide insight into crust formation on Mercury. These results suggested a primary floatation crust composed of graphite is possible given a magma ocean event on Mercury. Third, we experimentally determined the phase assemblages associated with the largest volcanic field on the planet. From this data we were able to provide insight into eruption scenarios that produced the northern volcanic plains on Mercury. Fourth, we determined the sulfide concentration at sulfide saturation in mercurian-like melts by conducting sulfide solubility experiments on a synthetic rock composition matching the northern volcanic plains. These results indicated that the high amounts of sulfur on the surface of Mercury measured by MESSENGER are a direct consequence of the low oxygen fugacity of the planet, which allowed transport of S towards the surface in reducing melts which have a higher carrying capacity for S than oxidized melts. Finally, we investigated the carbon concentration at graphite saturation in Fe-rich metals with various amounts of Si to determine the amount of C that would be soluble in the mercurian core as a function of core composition and temperature. The results of this dissertation provide important information regarding the evolution of Mercury from its primary magma ocean event to the current state of the planet
Hot Rocks! Near-Infrared Reflectances (and Emissivities) or Rocks at Venus Surface Temperatures
Venus surface can be viewed in emission through a few near-infrared (NIR) spectral windows (1 m) in its relatively opaque atmosphere [1]. Venus surface shows NIR emissivities that correlate with surface geology [2-4], and these emissivity variations are interpreted as differences in surface rock type (mafic vs. silicic) and/or extent of weathering (Fe2+ silicates vs. Fe3+-oxide-coated). To understand and quantify the observed variations in NIR emissivity, high-temperature (T) emissivity can be measured directly [5,6]. For example, emissivities of basalts in the wavelength range 0.85 1.2 m are ~0.95 [5-8]. This can be tested by measureing reflectance, because Kirchoffs Law holds that emissivity (e) = 1 reflectance (r). The r of basalt in the NIR is ~0.05 [o] consistent with a NIR e of ~0.95 [5-8]. High-T NIR es of silicic igneous rocks (granitic, rhyolite) have been reported to be 0.8-0.9 [5,6], which is inconsistent with r values of 0.3-0.8 of such rocks at 25C [9,10]. However, these measurements have been updated [7,8] and are consistent with the results here (see below and Fig. 3)
Experimental Insights into the Geochemistry of Mercury
With the recent estimate of Mercury's surface composition from the X-Ray Spectrometer and Gamma-Ray Spectrometer that were onboard NASA's MErcury Surface, Space ENvironment, Geochemistry and Ranging (MESSENGER) spacecraft, we now have our first opportunity to directly investigate the compositions of lavas from the planet Mercury and indirectly investigate the chemical make-up of its interior. Results from MESSENGER showed exotic surface compositions with more than 3 wt% sulfur in some lavas and relatively low amounts of iron (less than 3 wt%) across the surface. These striking features are consistent with magmatism occurring under highly reducing conditions which has an impact on the thermal and chemical evolution of a planetary body. Here we'll explore the geochemical evolution of Mercury through a series of experimental studies and discuss the implications of low oxygen fugacity on elemental behavior and magmatic processes
Möglichkeiten und Grenzen der ätiologischen Differenzierung der equinen Herpesvirusinfektionen
Using Simulated Micrometeoroid Impacts to Understand the Progressive Space Weathering of the Surface of Mercury
The surfaces of airless bodies such as Mercury are continually modified by space weathering, which is driven by micrometeoroid impacts and solar wind irradiation. Space weathering alters the chemical composition, microstructure, and spectral properties of surface regolith. In lunar and ordinarychondritic style space weathering, these processes affect the reflectance properties by darkening (lowering of reflectance), reddening (increasing reflectance with increasing wavelength), and attenuation of characteristic absorption features. These optical changes are driven by the production of nanophase Febearing particles (npFe). While our understanding of these alteration processes has largely been based on data from the Moon and near-Earth S-type asteroids, the space weathering environment at Mercury is much more extreme. The surface of Mercury experiences a more intense solar wind flux and higher velocity micrometeoroid impacts than its planetary counterparts at 1 AU. Additionally, the composition of Mercurys surface varies significantly from that of the Moon. Most notably, a very low albedo unit has been identified on Mercurys surface, known as the low reflectance material (LRM). This unit is enriched with up to 4 wt.% carbon, likely in the form of graphite, over the local mean. In addition, the surface concentration of Fe across Mercurys surface is low (<2 wt.%) compared to the Moon. Our understanding of how these low-Fe and carbon phases are altered as a result of space weathering processes is limited. Since Fe plays a critical role in the development of space weathering features on other airless surfaces (e.g., npFe), its limited availability on Mercury may strongly affect the space weathering features in surface materials. In order to understand how space weathering affects the chemical, microstructural, and optical properties of the surface of Mercury, we can simulate these processes in the laboratory [7]. Here we used pulsed laser irradiation to simulate the short duration, high temperature events associated with micrometeoroid impacts. We used forsteritic olivine, likely present on the Mercurian surface, with varying FeO contents, each mixed with graphite, in our experiments. We then performed reflectance spectroscopy and electron microscopy to investigate the spectral, chemical, and microstructural changes in these samples
Anpassungskonstruktion einer Kupplung und eines Viergangschaltgetriebes für einen Vierzylinderzweitaktverbrennungsmotor
Ziel dieser Arbeit ist die Eignungsuntersuchung vorhandener Komponenten und die konstruktive Gestaltung von neuen Komponenten für den Antriebsstrang eines Motorrades. Dies betrifft die Anpassungskonstruktion einer Kupplung, deren Antrieb und die eines Viergangschaltgetriebes an einen Vierzylinder- Zweitaktverbrennungsmotor. Im Rahmen dieser Arbeit ist ein Projekt fortgesetzt worden, dem die Konstruktion des Antriebsmotors vorausging. Mit dem Entwurf einer Antriebswelle für die Kupplung, die Konstruktion einer Lamellenkupplung, die Eignungsuntersuchung des Getriebes und des Getriebegehäuses und der Änderung der Getriebeschaltbetätigung ist dieses Projekt abgeschlossen worden
The Alphavirus 3′-Nontranslated Region: Size Heterogeneity and Arrangement of Repeated Sequence Elements
AbstractThe 3′-nontranslated region (NTR) of representative strains of all known alphavirus species was amplified by reverse transcription–polymerase chain reaction. For 23 of them, the 3′-NTR sequence was determined. Together with previously published data, this allowed an analysis of the 3′-NTR of the viruses in the genus Alphavirus. The length of the 3′-NTRs varied from 77 nt for Pixuna virus to 609 nt for Bebaru virus. The 19-nt conserved sequence element directly adjacent to the poly(A) tract was found in all viruses, supporting the hypothesis that this region is acis-acting sequence element during viral replication and essential for virus growthin vitro. Within the 3′-NTR of all alphaviruses, repeated sequence elements of various numbers and lengths were found. Their composition was very consistent in both the Venezuelan equine encephalitis (VEE) and the Sindbis-like viruses, although their number was constant only within the latter group. For the VEE viruses, our data suggested that insertion events rather than deletions from an ancestor with a long 3′-NTR created the various number of repeated sequence elements. Among the remaining viruses, both the number and the composition of repeated sequence elements varied remarkedly
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