An explicit construction of Wakimoto realizations of current algebras

It is known from a work of Feigin and Frenkel that a Wakimoto type, generalized free field realization of the current algebra $\widehat{\cal G}_k$ can be associated with each parabolic subalgebra ${\cal P}=({\cal G}_0+{\cal G}_+)$ of the Lie algebra ${\cal G}$, where in the standard case ${\cal G}_0$ is the Cartan and ${\cal P}$ is the Borel subalgebra. In this letter we obtain an explicit formula for the Wakimoto realization in the general case. Using Hamiltonian reduction of the WZNW model, we first derive a Poisson bracket realization of the ${\cal G}$-valued current in terms of symplectic bosons belonging to ${\cal G}_+$ and a current belonging to ${\cal G}_0$. We then quantize the formula by determining the correct normal ordering. We also show that the affine-Sugawara stress-energy tensor takes the expected quadratic form in the constituents.Comment: 13 pages, LaTeX; a typo corrected in (5.5-6), refs and a remark adde

Wakimoto realizations of current algebras: an explicit construction

A generalized Wakimoto realization of $\widehat{\cal G}_K$ can be associated with each parabolic subalgebra ${\cal P}=({\cal G}_0 +{\cal G}_+)$ of a simple Lie algebra ${\cal G}$ according to an earlier proposal by Feigin and Frenkel. In this paper the proposal is made explicit by developing the construction of Wakimoto realizations from a simple but unconventional viewpoint. An explicit formula is derived for the Wakimoto current first at the Poisson bracket level by Hamiltonian symmetry reduction of the WZNW model. The quantization is then performed by normal ordering the classical formula and determining the required quantum correction for it to generate $\widehat{\cal G}_K$ by means of commutators. The affine-Sugawara stress-energy tensor is verified to have the expected quadratic form in the constituents, which are symplectic bosons belonging to ${\cal G}_+$ and a current belonging to ${\cal G}_0$. The quantization requires a choice of special polynomial coordinates on the big cell of the flag manifold $P\backslash G$. The effect of this choice is investigated in detail by constructing quantum coordinate transformations. Finally, the explicit form of the screening charges for each generalized Wakimoto realization is determined, and some applications are briefly discussed.Comment: 38 pages, LaTeX, contains improved formulations of theorems 3 and 6, two references and a remark added, plus minor stylistic change

Confocal micro-XRF/XANES analysis on insects trapped in amber

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The epistemic integrity of scientific research

We live in a world in which scientific expertise and its epistemic authority become more important. On the other hand, the financial interests in research, which could potentially corrupt science, are increasing. Due to these two tendencies, a concern for the integrity of scientific research becomes increasingly vital. This concern is, however, hollow if we do not have a clear account of research integrity. Therefore, it is important that we explicate this concept. Following Rudolf Carnap's characterization of the task of explication, this means that we should develop a concept that is (1) similar to our common sense notion of research integrity, (2) exact, (3) fruitful, and (4) as simple as possible. Since existing concepts do not meet these four requirements, we develop a new concept in this article. We describe a concept of epistemic integrity that is based on the property of deceptiveness, and argue that this concept does meet Carnap's four requirements of explication. To illustrate and support our claims we use several examples from scientific practice, mainly from biomedical research

3D elemental imaging of the crustacean Ceriodaphnia by means of SR confocal micro-XRF

Daphnia is a freshwater crustacean (0.2-5 mm height) used for investigating the toxic effects of toxins (e.g. metals) on an ecosystem. Synchrotron radiation based micro X-ray fluorescence (SR micro-XRF) allows the investigation of the trace level metal distribution within these organisms in an essentially non-destructive manner. Several two-dimensional (2D), computed tomography (CT) and confocal micro-XRF experiments under conventional and cryogenic environments have been performed on Daphnia magna previously. However, due to its larger size (3 mm height) full three-dimensional (3D) imaging of the metal distributions is not practically feasible. In this contribution, we therefore report on the full 3D elemental imaging on Ceriodaphnia which is a smaller variant (1 mm height) by means of 3D confocal micro-XRF