857 research outputs found
Does understanding individuals require idiographic judgement?
Idiographic understanding has been proposed as a response to concern that criteriological diagnosis cannot capture the nature of human individuality. It can seem that understanding individuals requires, instead, a distinct form of ‘individualised’ judgement and this claim receives endorsement by the inventor of the term ‘idiographic’, Wilhelm Windelband. I argue, however, that none of the options for specifying a model of individualised judgement, to explain what idiographic judgement might be, will work. I suggest, at the end, that narrative, rather than idiographic, understanding is a more promising response to the limitations of criteriological diagnosis
Photon Echoes Produced by Switching Electric Fields
We demonstrate photon echoes in Eu:YSiO by controlling the
inhomogeneous broadening of the Eu
FD optical transition. This transition has
a linear Stark shift and we induce inhomogeneous broadening by applying an
external electric field gradient. After optical excitation, reversing the
polarity of the field rephases the ensemble, resulting in a photon echo. This
is the first demonstration of such a photon echo and its application as a
quantum memory is discussed.Comment: improved introduction, including theoretical outline of the relvant
quantum memory proposa
Photon echo quantum memories in inhomogeneously broadened two level atoms
Here we propose a solid-state quantum memory that does not require spectral
holeburning, instead using strong rephasing pulses like traditional photon echo
techniques. The memory uses external broadening fields to reduce the optical
depth and so switch off the collective atom-light interaction when desired. The
proposed memory should allow operation with reasonable efficiency in a much
broader range of material systems, for instance Er3+ doped crystals which have
a transition at 1.5 um. We present analytic theory supported by numerical
calculations and initial experiments.Comment: 7 pages, 8 figure
The Disjunctive Conception of Perceiving
John McDowell's conception of perceptual knowledge commits him to the claim that if I perceive that P then I am in a position to know that I perceive that P. In the first part of this essay, I present some reasons to be suspicious of this claim - reasons which derive from a general argument against 'luminosity' - and suggest that McDowell can reject this claim, while holding on to almost all of the rest of his conception of perceptual knowledge, by supplementing his existing disjunctive conception of experience with a new disjunctive conception of perceiving. In the second part of the essay, I present some reasons for thinking that one's justification, in cases of perceptual knowledge, consists not in the fact that one perceives that P but in the fact that one perceives such-and-such. I end by suggesting that the disjunctive conception of perceiving should be understood as a disjunctive conception of perceiving such-and-such
Chromosome position effects on gene expression in Escherichia coli K-12
In eukaryotes, the location of a gene on the chromosome is known to affect its expression, but such position effects are poorly understood in bacteria. Here, using Escherichia coli K-12, we demonstrate that expression of a reporter gene cassette, comprised of the model E. coli lac promoter driving expression of gfp, varies by ∼300-fold depending on its precise position on the chromosome. At some positions, expression was more than 3-fold higher than at the natural lac promoter locus, whereas at several other locations, the reporter cassette was completely silenced: effectively overriding local lac promoter control. These effects were not due to differences in gene copy number, caused by partially replicated genomes. Rather, the differences in gene expression occur predominantly at the level of transcription and are mediated by several different features that are involved in chromosome organization. Taken together, our findings identify a tier of gene regulation above local promoter control and highlight the importance of chromosome position effects on gene expression profiles in bacteria
Strong coupling cavity QED using rare-earth-ion dopants in monolithic resonators: what you can do with a weak oscillator
We investigate the possibility of achieving the strong coupling regime of
cavity quantum electrodynamics using rare earth ions as impurities in
monolithic optical resonators. We conclude that due to the weak oscillator
strengths of the rare earths, it may be possible but difficult, to reach the
regime where the single photon Rabi frequency is large compared to both the
cavity and atom decay rates. However reaching the regime where the saturation
photon and atom numbers are less than one should be much more achievable. We
show that in this `bad cavity' regime, transfer of quantum states and an
optical phase shift conditional on the state of the atom is still possible, and
suggest a method for coherent detection of single dopants.Comment: 10 pages, 6 figure
Role of contrast-enhanced ultrasound (CEUS) in paediatric practice: an EFSUMB position statement
The use of contrast-enhanced ultrasound (CEUS) in adults is well established in many different areas, with a number of current applications deemed off-label, but the use supported by clinical experience and evidence. Paediatric CEUS is also an off-label application until recently with approval specifically for assessment of focal liver lesions. Nevertheless there is mounting evidence of the usefulness of CEUS in children in many areas, primarily as an imaging technique that reduces exposure to radiation, iodinated contrast medium and the patient-friendly circumstances of ultrasonography. This position statement of the European Federation of Societies in Ultrasound and Medicine (EFSUMB) assesses the current status of CEUS applications in children and makes suggestions for further development of this technique
Can the strong get stronger? A laboratory investigation of natural selection for antimicrobial resistance
The students, Sarah Grace Keaveany and Elizabeth Ramsey, completed original research with to investigate 1) standing variation among common bacterial species (Escherichia coli and Stapholococcus epidermidis) in the amount of resistance to triclosan, a common anti-microbial used in hand washes; and 2) the capacity for these bacteria to develop increased resistance to triclosan through selection. The students have developed lab modules based on this research. One module includes a wet lab, where students will culture their own bacteria. The other module allows students to obtain data from photographs of bacterial plates in lieu of a wet lab component
Multi-Modal Properties and Dynamics of the Gradient Echo Quantum Memory
We investigate the properties of a recently proposed Gradient Echo Memory
(GEM) scheme for information mapping between optical and atomic systems. We
show that GEM can be described by the dynamic formation of polaritons in
k-space. This picture highlights the flexibility and robustness with regards to
the external control of the storage process. Our results also show that, as GEM
is a frequency-encoding memory, it can accurately preserve the shape of signals
that have large time-bandwidth products, even at moderate optical depths. At
higher optical depths, we show that GEM is a high fidelity multi-mode quantum
memory.Comment: 4 pages 3 figure
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