200 research outputs found
An Energy Balance Model on an Infinite Line
The thesis is an expansion of the work Gerald R. North did in 1975 on an energy balance climate model. By considering a similar model on an infinite line, and allowing the heat diffusion coefficient to vary on the line, more complicated behaviour arose from the model. Much of Norths work was recreated on the infinite lines, but a lot of new discoveries were made. Among what was found were spontaneous symmetry breaking, possible infinitely many solutions for a specific solar irradiation constant, bistability and in some cases tristability. Unconnected bifurcation diagrams were also found for some choices of unsymmetric heat diffusion function
War in Space: why not? A neorealist analysis of International Space Politics (1957-2018)
Why has there never been a space war? The most powerful states on Earth – the US,
China, Russia – have all developed anti-satellite weapons (ASATs), but they have never
used them to destroy each others satellites. This master thesis in International relations (IR)
finds that the distribution of space power in the international system has so far been prone to
peace in space, but the distribution is gradually becoming more dangerous. A history of
international politics between 1957 and 2018 is analysed using a theoretical framework built
on four different neorealist theories. If defined widely, neorealism can include at least
defensive neorealism (DN), offensive neorealism (ON), power transition theory (PTT) and
hegemonic stability theory (HST). The four theories have much in common, but are divided
on the question of war. DN and ON argues that a bipolar balance of power is the safest
system and multipolarity the most dangerous. PTT and HST argues that a preponderance
of power is the safest and power parity the main threat. Two hypotheses, one for each
“camp”, are formulated from the theories and tested against historical evidence on
international space politics in the period between 1957 and 2018. The conclusion is that the
distribution of space power has been bipolar in the First Space Age and unipolar in the
Second Space, but in the underlying components of space power neither the USSR/Russia
or China ever reached up to the US. However, China is rapidly catching up with the US both
in space power and the underlying components – and so are other powerful states. The
distribution of space power In the international system is becoming more multipolar, and a
rising challenger is approaching parity with the dominant one. Thus, according to both
camps of neorealism, the world is entering a period with higher risk for space war. The
thesis aims to be a stepping stone. Even neorealism, a prominent school within the
dominant realist paradigm, has rarely been used to analyse international space politics. The
goal of the thesis is to fill a gap in the growing IR literature on space and experiment with
neorealism to inspire further research on the topic.Por que nunca houve uma guerra espacial? As Grandes Potências - EUA, China e Rússia -
desenvolveram armas anti-satélite (ASATs), mas nunca as utilizaram para destruir os
satélites uns dos outros. Esta dissertação de mestrado em Relações Internacionais (RI) visa
evidenciar que a distribuição do poder espacial no sistema internacional tem sido até agora
propensa à paz no espaço, mas a mesma distribuição tende a tornar-se gradualmente mais
perigosa. Uma história da política internacional entre 1957 e 2018 é analisada recorrendo a
um quadro teórico construído sobre quatro diferentes teorias neo-realistas. Se amplamente
definido, o neo-realismo pode incluir, o neo-realismo defensivo (DN), o neo-realismo
ofensivo (ON), a teoria da transição de poder (PTT) e a teoria da estabilidade hegemónica
(HST). As quatro abordagens têm muito em comum, mas dividem-se sobre a questão da
guerra. DN e ON argumentam que a bipolaridade é a estrutura mais segura e a
multipolaridade a mais perigosa. PTT e HST argumentam que uma preponderância de
poder permite maior segurança, enquanto que a sua paridade é a principal ameaça. Duas
hipóteses, uma para cada “campo”, são formuladas a partir das teorias e testadas contra
evidências históricas da política espacial internacional no período compreendido entre 1957
e 2018. A conclusão é que a distribuição do poder espacial foi bipolar na Primeira Era
Espacial e unipolar na Segunda, mas a nível de componentes subjacentes ao poder
espacial, nem a URSS / Rússia nem a China alcançam os EUA. No entanto, a China – e
outras potências - está a alcançar rapidamente os EUA tanto no poder espacial quanto nos
componentes subjacentes. A distribuição do poder espacial no sistema internacional tende
a tornar-se multipolar, e uma potência desafiante aproxima-se da paridade com o poder
dominante. Assim, de acordo com os dois campos do neo-realismo, entramos num período
com maior risco de guerra espacial. Esta dissertação pretende funcionar como ponto de
partida e “trampolim”. Mesmo o neorrealismo, uma escola proeminente dentro do
paradigma realista dominante, raramente é utilizado para analisar a política espacial
internacional. O objetivo da dissertação é preencher uma lacuna na crescente literatura de
RI sobre o espaço, utilizando o neorrealismo para inspirar mais pesquisas sobre o tema
Digital compilation of geological maps from Dronning Maud Land
第6回極域科学シンポジウム[OG] 地圏11月16日(月) 国立極地研究所3階セミナー
Protocol for Isolation and Culture of Mouse Hepatocytes (HCs), Kupffer Cells (KCs), and Liver Sinusoidal Endothelial Cells (LSECs) in Analyses of Hepatic Drug Distribution
Development of the new generation of drugs (e.g., oligo- and polynucleotides administered intravascularly either as free compounds or as nano-formulations) frequently encounters major challenges such as lack of control of targeting and/or delivery. Uncontrolled or unwanted clearance by the liver is a well-known and particularly important hurdle in this respect. Hence, reliable techniques are needed to identify the type(s) of liver cells, receptors, and metabolic mechanisms that are responsible for unwanted clearance of these compounds.
We describe here a method for the isolation and culture of the major cell types from mouse liver: hepatocytes (HCs), Kupffer cells (KCs), and liver sinusoidal endothelial cells (LSECs). The presently described protocol employs perfusion of the liver with a collagenase-based enzyme preparation to effectively transform the intact liver to a single cell suspension. From this initial cell suspension HCs are isolated by specified centrifugation schemes, yielding highly pure HC preparations, and KCs and LSECs are isolated by employing magnetic-activated cell sorting (MACS). The MACS protocol makes use of magnetic microbeads conjugated with specific antibodies that bind unique surface antigens on either KCs or LSECs. In this way the two cell types are specifically and separately pulled out of the initial liver cell suspension by applying a magnetic field, resulting in high purity, yield, and viability of the two cell types, allowing functional studies of the cells.
If the drug compound in question is to be studied with respect to liver cell distribution of intravascularly administered drug compounds the isolated cells can be analyzed directly after isolation. Detailed studies of receptor-ligand interactions and/or dynamics of intracellular metabolism of the compound can be conducted in primary surface cultures of HCs, LSECs, and KCs established by seeding the isolated cells on specified growth substrates
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