634 research outputs found
Non-classical Photon Statistics For Two-mode Optical Fields
The non-classical property of subpoissonian photon statistics is extended
from one to two-mode electromagnetic fields, incorporating the physically
motivated property of invariance under passive unitary transformations.
Applications to squeezed coherent states, squeezed thermal states, and
superposition of coherent states are given. Dependences of extent of
non-classical behaviour on the independent squeezing parameters are graphically
displayed.Comment: 15 pages, RevTex, 5 figures, available by sending email to
[email protected]
Electrospray Micromixer Chip for On-Line Derivatization and Kinetic Studies
An electrospray microchip for mass spectrometry comprising an integrated passive mixer to carry out on-chip chemical derivatizations is described. The microchip fabricated using UV-photoablation is composed of two microchannels linked together by a liquid junction. Downstream of this liquid junction, a mixing unit made of parallel oblique grooves is integrated to the microchannel in order to create flow perturbations. Several mixer designs are evaluated. The mixer efficiency is investigated both by fluorescence study and mass spectrometric monitoring of the tagging reaction of cysteinyl peptides with 1,4-benzoquinone. The comparisons with a microchip without a mixing unit and a kinetic model are used to assess the efficiency of the mixer showing tagging kinetics close to that of bulk reactions in an ideally mixed reactor. As an ultimate application, the electrospray micromixer is implemented in a LC-MS workflow. Online derivatization of albumin tryptic peptides after a reversed-phase separation and counting of their cysteines drastically enhance the protein identification
The Real Symplectic Groups in Quantum Mechanics and Optics
text of abstract (We present a utilitarian review of the family of matrix
groups , in a form suited to various applications both in optics
and quantum mechanics. We contrast these groups and their geometry with the
much more familiar Euclidean and unitary geometries. Both the properties of
finite group elements and of the Lie algebra are studied, and special attention
is paid to the so-called unitary metaplectic representation of .
Global decomposition theorems, interesting subgroups and their generators are
described. Turning to -mode quantum systems, we define and study their
variance matrices in general states, the implications of the Heisenberg
uncertainty principles, and develop a U(n)-invariant squeezing criterion. The
particular properties of Wigner distributions and Gaussian pure state
wavefunctions under action are delineated.)Comment: Review article 43 pages, revtex, no figures, replaced because
somefonts were giving problem in autometic ps generatio
Community Reaction to Bioterrorism: Prospective Study of Simulated Outbreak
To assess community needs for public information during a bioterrorism-related crisis, we simulated an intentional Rift Valley fever outbreak in a community in the southern part of the United States. We videotaped a series of simulated print and television “news reports” over a fictional 9-day crisis period and invited various groups (e.g., first-responders and their spouses or partners, journalists) within the selected community to view the videotape and respond to questions about their reactions. All responses were given anonymously. First-responders and their spouses or partners varied in their reactions about how the crisis affected family harmony and job performance. Local journalists exhibited considerable personal fear and confusion. All groups demanded, and put more trust in, information from local sources. These findings may have implications for risk communication during bioterrorism-related outbreaks
Understanding the dynamics of Toll-like Receptor 5 response to flagellin and its regulation by estradiol
© 2017 The Author(s). Toll-like receptors (TLRs) are major players of the innate immune system. Once activated, they trigger a signalling cascade that leads to NF-ΰ B translocation from the cytoplasm to the nucleus. Single cell analysis shows that NF-ΰ B signalling dynamics are a critical determinant of transcriptional regulation. Moreover, the outcome of innate immune response is also affected by the cross-talk between TLRs and estrogen signalling. Here, we characterized the dynamics of TLR5 signalling, responsible for the recognition of flagellated bacteria, and those changes induced by estradiol in its signalling at the single cell level. TLR5 activation in MCF7 cells induced a single and sustained NF-k B translocation into the nucleus that resulted in high NF-k B transcription activity. The overall magnitude of NF-k B transcription activity was not influenced by the duration of the stimulus. No significant changes are observed in the dynamics of NF-k B translocation to the nucleus when MCF7 cells are incubated with estradiol. However, estradiol significantly decreased NF-k B transcriptional activity while increasing TLR5-mediated AP-1 transcription. The effect of estradiol on transcriptional activity was dependent on the estrogen receptor activated. This fine tuning seems to occur mainly in the nucleus at the transcription level rather than affecting the translocation of the NF-k B transcription factor
Genomic Deletion Marking an Emerging Subclone of \u3ci\u3eFrancisella tularensis\u3c/i\u3e subsp. \u3ci\u3eholarctica\u3c/i\u3e in France and the Iberian Peninsula
Francisella tularensis subsp. holarctica is widely disseminated in North America and the boreal and temperate regions of the Eurasian continent. Comparative genomic analyses identified a 1.59-kb genomic deletion specific to F. tularensis subsp. holarctica isolates from Spain and France. Phylogenetic analysis of strains carrying this deletion by multiple-locus variable-number tandem repeat analysis showed that the strains comprise a highly related set of genotypes, implying that these strains were recently introduced or recently emerged by clonal expansion in France and the Iberian Peninsula
Osmosis in a minimal model system
Osmosis plays a central role in the function of living and soft matter
systems. While the thermodynamics of osmosis is well understood, the underlying
microscopic dynamical mechanisms remain the subject of discussion. Unraveling
these mechanisms is a crucial prerequisite for eventually understanding osmosis
in non-equilibrium systems. Here, we investigate the microscopic basis of
osmosis, in a system at equilibrium, using molecular dynamics simulations of a
minimal model in which repulsive solute and solvent particles differ only in
their interactions with an external potential. For this system, we can derive a
simple virial-like relation for the osmotic pressure. Our simulations support
an intuitive picture in which the solvent concentration gradient, at osmotic
equilibrium, arises from the balance between an outward force, caused by the
increased total density in the solution, and an inward diffusive flux caused by
the decreased solvent density in the solution. While more complex effects may
occur in other osmotic systems, they are not required for a description of the
basic physics of osmosis in this minimal model.Comment: 10 pages, 8 figure
Advantage of rare infanticide strategies in an invasion experiment of behavioural polymorphism
Killing conspecific infants (infanticide) is among the most puzzling phenomena in nature. Stable polymorphism in such behaviour could be maintained by negative frequency-dependent selection (benefit of rare types). However, it is currently unknown whether there is genetic polymorphism in infanticidal behaviour or whether infanticide may have any fitness advantages when rare. Here we show genetic polymorphism in non-parental infanticide. Our novel invasion experiment confirms negative frequency-dependent selection in wild bank vole populations, where resource benefits allow an infanticidal strategy to invade a population of non-infanticidal individuals. The results show that infanticidal behaviour is highly heritable with genetic correlation across the sexes. Thus, a positive correlative response in male behaviour is expected when selection operates on females only and vice versa. Our results, on one hand, demonstrate potential benefits of infanticide, and on the other, they open a new perspective of correlative evolution of infanticide in females and males
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