4,645 research outputs found
Positional information readout in signaling
Living cells respond to spatial signals. Signal transmission to the cell
interior often involves the release of second messengers like . They
will eventually trigger a physiological response by activating kinases that in
turn activate target proteins through phosphorylation. Here, we investigate
theoretically how positional information can be accurately read out by protein
phosphorylation in spite of rapid second messenger diffusion. We find that
accuracy is increased by binding of the kinases to the cell membrane prior to
phosphorylation and by increasing the rate of loss from the cell
interior. These findings could explain some salient features of conventional
protein kinases C
Gravitational Lorentz anomaly from the overlap formula in 2-dimensions
In this letter we show that the overlap formulation of chiral gauge theories
correctly reproduces the gravitational Lorentz anomaly in 2-dimensions. This
formulation has been recently suggested as a solution to the fermion doubling
problem on the lattice. The well known response to general coordinate
transformations of the effective action of Weyl fermions coupled to gravity in
2-dimensions can also be recovered.Comment: 7 pages, late
Studies of the dissolved organic compounds in the sea - A preliminary report on the isolation, separation and identification of free amino acids
A method of concentrating and desalting sea water using evaporation
and ion exchange techniques is described. Circular paper chromatography
has been used to separate and identify free amino acids
in desalted concentrates of sea water from three different localities
along the Norwegian coast. The following amino acids have so far
been identified: cystine, lysine, histidine, arginine, serine, aspartic
acid, glycine, hydroxyproline, glutamic acid, threonine, α-alanine,
proline, tyrosine, tryptophan, methionine, valine, β-phenylalanine,
isoleucine and leucine
World War I and the Idea of Progress in Powers\u27s Three Farmers on Their Way to a Dance
In his article World War I and the Idea of Progress in Powers\u27s Three Farmers on Their Way to a Dance Karsten H. Piep reads Powers\u27s 1985 novel as a critical reexamination of the dynamics and iconography of the early twentieth century that challenges the technological positivism espoused by many U.S. neoconservatives during the 1980s, while insisting on the individual\u27s interpretive powers to discern and release the ever present transformative potentials of history. Situating Three Farmers in the postmodernism debates of the 1980s, Piep argues that the novel succeeds in challenging the idea of history conceived as linear progression, but fails to show how a critical engagement with the past might engender social transformation in the present
Separatist Nationalism in Gilbert Imlay\u27s The Emigrants
Karsten H. Piep, in his paper Separatist Nationalism in Gilbert Imlay\u27s The Emigrants, argues that only recently rediscovered among American scholars and still awaiting much critical work, Gilbert Imlay\u27s The Emigrants offers an intriguing case study in the complex relationship between fictional representation and late eighteenth-century nation formation. Tracing briefly the novel\u27s reception history, Piep locates The Emigrants within the socio-political context of eighteenth-century discourses on revolution, emancipation, and independence. Taking Benedict Anderson\u27s study on the rise of nationalism as a point of reference, Piep argues that Imlay\u27s novel offers an example of a perhaps uniquely American separatist nationalism that proffers, employs, expands, and subverts official or dominant accounts of nationalism by inviting a transatlantic readership to imagine an utopian community in the remote Ohio River Valley. Piep also explores in his study how novelistic representations of Benedict Anderson\u27s notion of homogenous, empty time can be applied with regard to transatlantic imaginings of alternative communities in Imlay\u27s novel
The Charter of the United Nations: An Instrument to Re-Establish International Peace and Security?
Constraints on the Existence of Chiral Fermions in Interacting Lattice Theories
It is shown that an interacting theory, defined on a regular lattice, must
have a vector-like spectrum if the following conditions are satisfied:
(a)~locality, (b)~relativistic continuum limit without massless bosons, and
(c)~pole-free effective vertex functions for conserved currents.
The proof exploits the zero frequency inverse retarded propagator of an
appropriate set of interpolating fields as an effective quadratic hamiltonian,
to which the Nielsen-Ninomiya theorem is applied.Comment: LaTeX, 9 pages, WIS--93/56--JUNE--P
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