Tropospheric water vapour observations by ground-based lidar

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Recoil effects on nucleon electromagnetic form factors

The electromagnetic form factors are computed using eigenstates of linear momentum for the nucleon. The latter is described in the framework of the chiral color-dielectric model, projecting the hedgehog ansatz on eigenstates of angular momentum and isospin. Form factors are well reproduced, with the exception of the magnetic one for the proton, up to $q^2 \simeq 0.5$ GeV$^2$. The effect of the removal of the spurious center-of-mass contributions shows up mainly in the electric form factor of the proton. A noticeable improvement is obtained with respect to the calculation without linear momentum projection.Comment: LateX file (with ESPART.STY) + 4 postscript figure

Russell and American realism

American philosophical realism developed in two forms: “new” and “critical” realism. While the new realists sought to ‘emancipate’ ontology from epistemology and defended a direct theory of perception, the critical realists promoted a representationalist account of perception and thus argued for an epistemological dualism. Bertrand Russell’s early philosophical writings figured prominently in both of these American realist camps. However, while the new realists quite enthusiastically embraced the Russellian analytic style of reasoning (and Russell himself appreciated the American new realists as anti-idealist allies), the critical realists were significantly more reserved toward Russell’s point of view. In the present paper, I identify the reasons for this difference in reception. In particular, I will show that the critical realists’ reservations pertained primarily to a more traditionalist—‘continental’—account of philosophy, whereas the neo-realists proved instrumental in setting the stage for later full-blown analytic philosophy in the United States

Nanosecond Stimulation and Defibrillation of Langendorff-Perfused Rabbit Hearts

The search for novel defibrillation methodologies focuses on minimizing deposition of energy to the heart, as this is an indicator for side effects including pain and tissue death. In this work, we investigate the effect of reducing the duration of the applied shocks from low milliseconds to the nanosecond range. 300 ns defibrillation was observed and confirmed to require lower energy than monophasic shocks by almost an order of magnitude with no tissue damage. Additionally, the safety factor, the ratio of median effective doses for electroporative damage and defibrillation, was similar for both durations. To predict how defibrillation shocks of any duration affect the heart, the stimulation strength-duration curve from 200 ns to 10 ms was determined. To investigate whether high frequency trains of nanosecond shocks (MHz compression) are capable of reducing the electric field and energy of defibrillation, they were compared with a single shock of the same duration. The average voltage for the pulse trains was slightly lower than for long shocks, but the energy almost doubled. Finally, to understand how shocks even shorter than 300 ns perform, we attempted to determine the defibrillation threshold of 60 ns shocks. Both the estimated electric field and energy were markedly higher than for 300 ns. We also investigated the stimulation threshold of 60 ns shocks followed by a negative phase of varying amplitude and showed that the negative phase reduces the ability of the shocks to stimulate. In conclusion, this work contributes to the understanding of how nanosecond shocks interact with cardiac tissues. It shows that 300 ns defibrillation is effective and similarly safe as 10 ms shocks, while requiring almost an order of magnitude less energy. The stimulation strength duration curve for cardiac tissue follows the same trend, with lower than expected thresholds for nanosecond shocks. However, low voltage MHz compressed nanosecond shocks are similarly effective as long shocks of the same duration, indicating that the greater efficacy of nanosecond defibrillation is linked to the effects of high voltage. Finally, investigations in 60 ns shocks show defibrillation and stimulation are possible, and that bipolar cancellation occurs in cardiac tissue

Stefan George Digital

Projektberich

Realistic Claims in Logical Empiricism

Logical empiricism is commonly seen as a counter-position to scientific realism. In the present paper it is shown that there indeed existed a realist faction within the logical empiricist movement. In particular, I shall point out that at least four types of realistic arguments can be distinguished within this faction: Reichenbach’s ‘probabilistic argument,’ Feigl’s ‘pragmatic argument,’ Hempel’s ‘indispensability argument,’ and Kaila’s ‘invariantist argument.’ All these variations of arguments are intended to prevent the logical empiricist agenda from the shortcomings of radical positivism, instrumentalism, and other forms of scientific antirealism. On the whole, it will be seen that logical empiricism and scientific realism are essentially compatible with each other. Especially Kaila’s invariantist approach to science (and nature) comes quite close to what nowadays is discussed under the label ‘structural realism.’ This, in turn, necessitates a fundamental reevaluation of Kaila’s role in the logical empiricist movement in particular and in twentieth-century philosophy of science in general

Essays in Behavioral Economics

This thesis consists of five chapters that contribute to understanding the consequences, measurement, and origins of heterogeneity in preferences. Underneath this overarching topic, several different threads are weaving together the elements of this thesis. The first such theme is introspection, the second prosocial and moral decision-making, and a third the combination of behavioral and survey measures. The first two chapters study individual behavior in the domains of fairness and helping. In line with the idea that emotional introspection is a key mechanism by which people understand normative obligations and needs, both chapters provide evidence from lab experiments that people intuitively tend to act like they would want others to act. Specifically, the first chapter shows that people prioritize norms from which they benefit themselves, even when unaffected by their own behavior. Similarly, the main result of the second chapter is that in deciding about help, own preferences influence the appreciation of others' utility. The third chapter moves the focus from the individual to the group. Two lab experiments show that when responsibility is diffused among different people, moral behavior decays. The fourth chapter relates to the first two in that it is concerned with introspection. We theoretically and empirically explore how self-knowledge can be inferred from the compression of survey answers and demonstrate that corresponding estimates can improve survey evidence. The last chapter is itself based on survey data. It contributes to understanding the origins of global heterogeneity in preferences, finding that countries' historical experience with statehood has shaped their present levels of patience