The Early Cartography of the Bering Strait Region

... In its later phase, from the mid-seventeenth century on, the locale of this mythical strait was shifted eastward to a position between a legendary land of Jeso and America north of California, and became involved in the controversy over a Northwest Passage from Hudson's Bay to the Pacific. It was at this time that another cartography began to develop, based at first on a slim and tenuous knowledge of the facts, but nevertheless carrying with it the promise of a realistic cartography of the Bering Strait region. This was the Russian cartography of northeastern Siberia. Less is generally known about this cartography than about that of the Strait of Anian; yet, since World War II, Soviet scholars have greatly advanced our knowledge of it. This paper will focus on a selected group of maps from the Russian cartography. ..

Different Transport Pathways of Individual Precursor Proteins in Mitochondria

Transport of mitochondrial precursor proteins into mitochondria of Neurospora crassa was studied in a cellfree reconstituted system. Precursors were synthesized in a reticulocyte lysate programmed with Neurospora mRNA and transported into isolated mitochondria in the absence of protein synthesis. Uptake of the following precursors was investigated: apocytochrome c, ADP/ATP carrier and subunit 9 of the oligomycin-sensitive ATPase. Addition of high concentrations of unlabelled chemically prepared apocytochrome c (1–10 μM) inhibited the appearance in the mitochondrial of labelled cytochrome c synthesized in vitro because the unlabelled protein dilutes the labelled one and because the translocation system has a limited capacity [apparent V is 1–3 pmol × min−1× (mg mitochondrial protein)−1]. Concentrations of added apocytochrome c exceeding the concentrations of precursor proteins synthesized in vitro by a factor of about 104 did not inhibit the transfer of ADP/ATP carrier or ATPase subunit 9 into mitochondria. Carbonylcyanide m-chlorophenylhydrazone, an uncoupler of oxidative phosphorylation, inhibited transfer in vitro of ADP/ATP carrier and of ATPase subunit 9, but not of cytochrome c. These findings suggest that cytochrome c and the other two proteins have different import pathways into mitochondria. It can be inferred from the data presented that different 'receptors' on the mitochondrial surface mediate the specific recognition of precursor proteins by mitochondria as a first step in the transport process

Pearling and Pinching: Propagation of Rayleigh Instabilities

A new category of front propagation problems is proposed in which a spreading instability evolves through a singular configuration before saturating. We examine the nature of this front for the viscous Rayleigh instability of a column of one fluid immersed in another, using the marginal stability criterion to estimate the front velocity, front width, and the selected wavelength in terms of the surface tension and viscosity contrast. Experiments are suggested on systems that may display this phenomenon, including droplets elongated in extensional flows, capillary bridges, liquid crystal tethers, and viscoelastic fluids. The related problem of propagation in Rayleigh-like systems that do not fission is also considered.Comment: Revtex, 7 pages, 4 ps figs, PR

The Computational Complexity of Generating Random Fractals

In this paper we examine a number of models that generate random fractals. The models are studied using the tools of computational complexity theory from the perspective of parallel computation. Diffusion limited aggregation and several widely used algorithms for equilibrating the Ising model are shown to be highly sequential; it is unlikely they can be simulated efficiently in parallel. This is in contrast to Mandelbrot percolation that can be simulated in constant parallel time. Our research helps shed light on the intrinsic complexity of these models relative to each other and to different growth processes that have been recently studied using complexity theory. In addition, the results may serve as a guide to simulation physics.Comment: 28 pages, LATEX, 8 Postscript figures available from [email protected]

Kondo engineering : from single Kondo impurity to the Kondo lattice

In the first step, experiments on a single cerium or ytterbium Kondo impurity reveal the importance of the Kondo temperature by comparison to other type of couplings like the hyperfine interaction, the crystal field and the intersite coupling. The extension to a lattice is discussed. Emphasis is given on the fact that the occupation number $n_f$ of the trivalent configuration may be the implicit key variable even for the Kondo lattice. Three $(P, H, T)$ phase diagrams are discussed: CeRu$_2$Si$_2$, CeRhIn$_5$ and SmS

Feasibility of Surgeon-Delivered Audit and Feedback Incorporating Peer Surgical Coaching to Reduce Fistula Incidence following Cleft Palate Repair: A Pilot Trial

Background: Improving surgeons\u27 technical performance may reduce their frequency of postoperative complications. The authors conducted a pilot trial to evaluate the feasibility of a surgeon-delivered audit and feedback intervention incorporating peer surgical coaching on technical performance among surgeons performing cleft palate repair, in advance of a future effectiveness trial. Methods: A nonrandomized, two-arm, unblinded pilot trial enrolled surgeons performing cleft palate repair. Participants completed a baseline audit of fistula incidence. Participants with a fistula incidence above the median were allocated to an intensive feedback intervention that included selecting a peer surgical coach, observing the coach perform palate repair, reviewing operative video of their own surgical technique with the coach, and proposing and implementing changes in their technique. All others were allocated to simple feedback (receiving audit results). Outcomes assessed were proportion of surgeons completing the baseline audit, disclosing their fistula incidence to peers, and completing the feedback intervention. Results: Seven surgeons enrolled in the trial. All seven completed the baseline audit and disclosed their fistula incidence to other participants. The median baseline fistula incidence was 0.4 percent (range, 0 to 10.5 percent). Two surgeons were unable to receive the feedback intervention. Of the five remaining surgeons, two were allocated to intensive feedback and three to simple feedback. All surgeons completed their assigned feedback intervention. Among surgeons receiving intensive feedback, fistula incidence was 5.9 percent at baseline and 0.0 percent following feedback (adjusted OR, 0.98; 95 percent CI, 0.44 to 2.17). Conclusion: Surgeon-delivered audit and feedback incorporating peer coaching on technical performance was feasible for surgeons

Competition and Complementarity in Diffusion: The Case of Octane

The standard ontogenic (life-cycle) model of technological evolution can be characterized briefly as follows (Ayres, 1987): (1) a radical invention (birth) creates a new technology; (2) it is commercialized on the basis of performance and rapidly developed by a series of improvements and modifications (infancy); (3) it is successful enough in the marketplace to attract many variants and imitators who hope to exploit a growing market (adolescence); (4) the pace of technological change finally slows down enough to permit standardization and exploitation of economies of scale, and competition on the basis of price rather than performance (maturity); and finally a new and better technology supplants it (senescence)