2,858 research outputs found
Impact perforation testing of stab-resistant armour materials
This paper describes the development of a method for the investigation and comparison of materials for use in stab resistant body armour. A number of polymer composite panels of different thicknesses and construction have been tested. A dynamic test which simulated the real threat has been used and the results compared to a simpler quasi-static test that might be used in initial materials selection. The materials tested were glass-epoxy, and glass-nylon composite panels of several thicknesses between 1.8 and 5.8mm. Additional tests were also performed on similar composites containing tungsten wires. An accelerated instrumented drop-tower was used to drive a knife through composite panels and record the force resisting penetration by the knife. The final penetration of the knife through the armour into a soft backing was also measured. For comparison,a similar geometry quasi-static test was carried out on the same specimens. It was found that energy absorbtion took the form of an initial resistance to perforation and then by a resistance to further penetration. This is thought to stem from resistance to cutting ofthe panel material and gripping of the knife blade. The energy required to produce a given penetration in dynamic tests was found to be in good agreement with the penetration achieved at similar energies under quasi-static conditions. For the materials tested there was no significant difference between the penetration resistance of single or two layer systems. The penetration achieved through a panel of a given material was approximately proportional to the inverse square of the panel's thickness. The relative performance of different armour materials was assessed by plotting the energy required to penetrate a fixed distance against the areal density of the panel
Investigating the evolution of apoptosis in malaria parasites: the importance of ecology
Apoptosis is a precisely regulated process of cell death which occurs widely in multicellular organisms and is essential for normal development and immune defences. In recent years, interest has grown in the occurrence of apoptosis in unicellular organisms. In particular, as apoptosis has been reported in a wide range of species, including protozoan malaria parasites and trypanosomes, it may provide a novel target for intervention. However, it is important to understand when and why parasites employ an apoptosis strategy before the likely long-and short-term success of such an intervention can be evaluated. The occurrence of apoptosis in unicellular parasites provides a challenge for evolutionary theory to explain as organisms are expected to have evolved to maximise their own proliferation, not death. One possible explanation is that protozoan parasites undergo apoptosis in order to gain a group benefit from controlling their density as this prevents premature vector mortality. However, experimental manipulations to examine the ultimate causes behind apoptosis in parasites are lacking. In this review, we focus on malaria parasites to outline how an evolutionary framework can help make predictions about the ecological circumstances under which apoptosis could evolve. We then highlight the ecological considerations that should be taken into account when designing evolutionary experiments involving markers of cell death, and we call for collaboration between researchers in different fields to identify and develop appropriate markers in reference to parasite ecology and to resolve debates on terminology.Host-parasite interactio
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The Welfare Implications of Oil Privatisation: A Cost-Benefit Analysis of Norway's Statoil
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Restructuring the Chinese Electricity Supply Sector: An assessment of the market pilot in Guangdong Province
This paper examines power sector reform in China�s largest province, Guangdong, following the publication of the No.9 document of the China State Council on �Deepening Reform of the Power Sector� in March 2015. We look at the operation of the pilot wholesale power market in Guangdong in the light of international experience. We discuss how the power market pilot is working in Guangdong and the extent to which the current market design is in line with successful power markets we see elsewhere. We examine the evidence on whether the market reform has successfully brought new players into the electricity system in Guangdong. We consider the effects of the reform on the operational and investment decisions of firms in the sector. We conclude with several lessons for the Chinese government�s ongoing power sector reform programme
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What effect has the 2015 power market reform had on power prices in China? Evidence from Guangdong and Zhejiang
This paper presents an analysis of the impact of the recent power market reform process in China – following the No.9 Document of March 2015 – on the industrial price of electricity. We do this by picking a typical power price for a medium sized industrial customer in two of China’s leading reform provinces: Guangdong and Zhejiang. We find that power market reform, which is characterised by the introduction of wholesale electricity markets, has substantially reduced prices. Our detailed analysis shows that these price falls have come from a number of different sources: falls in the prices paid to generators, reductions in grid charges and falls in government taxes and additional charges. We show that the regulated price falls by 26.4% in Guangdong and by 26.9% in Zhejiang. The market price falls even further by 27.7% in Guangdong and 30.4% in Zhejiang. We conclude that while the impact of the power markets is significant, the associated changes to network charges and other government determined components of the price are more significant
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China’s Energy Law Draft and the Reform of its Electricity Supply Sector
China is reforming its electricity supply industry under the guidance of the No.9 document published in 2015. However, such reform has not been supported by new legislation until now. China unveiled an Energy Law draft in April 2020 for public consultati
Solidifying system of democracy in the Central and Eastern European new EU members
The paper examines the requirements of an effective and legitimized democratic political system in the process of transition. The analysis and the conclusions are based on the Hungarian experience, which can carefully be applied to all Central and Eastern European (CEE) countries. Special focus is given to the relationship of legal certainty and the efficiency of the democratic system, to the tension between legalism and managerialism and to the characteristics of civil society organizations. In the conclusion special features of the transitional countries are pointed out
Valtion aluehallintovirastot ja niiden ylijohtajat: Pohjoiseurooppalainen analogia Ranskan prefeikteille
This chapter examines the closest Finnish analogy to the French function of the prefect. In Finland, since 2010, this function has been vested in the institution of the State Regional Administrative Agency (SRAA, aluehallintovirasto, ‘AVI’). There are six SRAAs, each headed by a Chief Director (ylijohtaja) nominated by the government. The study had four main findings. First, despite ambiguity in institutional terminology, classifications, boundaries and identities concerning the SRAA, one can discern few true functional or structural deficiencies. Second, the SRAA is a hybrid between an institution of its own and a territorial representative of either government ministries or government agencies, to which is related the fact that each SRAA has both responsibilities concerning its territory and nationwide responsibilities. Third, tensions between performance and institutional legitimation prevail in the institution of the SRAA, but again without serious deficiencies. Fourth, the 2010 substitution of the SRAA for the former Province comprised a radical institutional change. The 2015–2019 Finnish government intended to abolish the SRAAs, but the subsequent government abandoned that reform, and ultimately by mid-2020 it became clear that the institution of the SRAA was here to stay after all.Peer reviewe
Evolutionary ecology of transmission strategies in protozoan parasites
In recent years there has been growing interest in applying frameworks from
evolutionary ecology to understand infectious disease. It is becoming increasingly
apparent that the interactions between parasites within the host environment can
shape parasite phenotypes underlying infection dynamics and transmission.
However, the spread of the disease will crucially depend on both within-host and
between-host dynamics. Bridging these scales is challenging and for vector borne
parasites, such as malaria and trypanosomes, will involve gaining a much better
understanding of infection dynamics both within the host and vector. I apply
evolutionary ecology frameworks including social evolution, life history theory,
and phenotypic plasticity to investigate how parasite phenotypes are shaped by
within-host and within-vector environments and examine the implications for inhost
survival and between-host transmission. Specifically, I demonstrate that;
1. Within the host;
i. In accordance with theory malaria parasites detect and respond to the
presence of competitors by altering reproductive strategies to
maximise in-host survival. Furthermore, these strategies are fine
tuned in response to variation in the within-host environment,
including the availability of resources.
ii. The reproductive investment strategies of malaria parasites can be
applied to explain the transmission strategies of African
trypanosomes. This shows how general evolutionary frameworks can
be applied to a novel parasite species and demonstrates the
explanatory power of an evolutionary approach.
iii. The complexity of the within-host environment poses specific
statistical challenges for examining the temporal dynamics of parasite
life history traits that are often not adequately dealt with, potentially
leading to type 1 errors. Methods to evaluate levels of autocorrelation
and how to deal with it are applied to datasets of within-infection
dynamics.
2. Within the vector;
i. Malaria parasites undergo programmed, apoptotic cell death. The
occurrence of, and putative explanation for, apoptosis in protozoan
parasites is controversial. I demonstrate the importance of
quantitative methods and parasite ecology in testing the evolutionary
explanations for parasite apoptosis.
ii. The links between within-host dynamics and within-vector dynamics
are complex and can lead to counter-intuitive implications for the
success of between-host transmission. Density-dependent processes
result in diverse fitness costs to parasites of crowding. More broadly,
these processes could explain why parasites undergo apoptosis.
In general my results demonstrate, across vertebrate hosts and insect vectors, how
the interactions between parasites and with their environment shapes traits
important for the transmission of infectious disease
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