Structural Complexity of Random Binary Trees

Abstract — For each positive integer n, let Tn be a random rooted binary tree having finitely many vertices and exactly n leaves. We can view H(Tn), the entropy of Tn, as a measure of the structural complexity of tree Tn in the sense that approximately H(Tn) bits suffice to construct Tn. We are interested in determining conditions on the sequence (Tn: n = 1, 2, · · ·) under which H(Tn)/n converges to a limit as n → ∞. We exhibit some of our progress on the way to the solution of this problem. I

On a zero speed sensitive cellular automaton

Using an unusual, yet natural invariant measure we show that there exists a sensitive cellular automaton whose perturbations propagate at asymptotically null speed for almost all configurations. More specifically, we prove that Lyapunov Exponents measuring pointwise or average linear speeds of the faster perturbations are equal to zero. We show that this implies the nullity of the measurable entropy. The measure m we consider gives the m-expansiveness property to the automaton. It is constructed with respect to a factor dynamical system based on simple "counter dynamics". As a counterpart, we prove that in the case of positively expansive automata, the perturbations move at positive linear speed over all the configurations

Mariner 1969 Infrared Radiometer Results: Temperatures and Thermal Properties of the Martian Surface

The reduced data of the Mariner 6 and 7 Infrared Radiometer Experiments are presented, along with a discussion of the reduction and calibration procedures. Evidence is presented showing that the surface of Mars is strongly nonhomogeneous in its thermal properties, on scales ranging from those of the classical light and dark areas to the limit of resolution of the radiometers. On the sunlit side, the mean thermal inertia, for admissible bolometric albedos, is 0.006 (cal cm^(-2) sec^(-1/2) °K^(-1)). The dark areas Syrtis Major and Mare Tyrrhenum, observed at night, require thermal inertias as high as 0.010. The temperatures measured over the circular basin Hellas require a bolometric albedo of 0.40 and also a high thermal inertia. The temperature measured over the south polar cap, 148° K, provides evidence that the major constituent of the frost deposit is CO_2

The Effect of Caffeine on Motor Task Performance

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Preliminary report on infrared radiometric measurements from the Mariner 9 spacecraft

Preliminary 10- and 20-μm brightness temperatures of Mars are presented. More than 35% of the Martian surface was observed with a resolution better than 100 km. On the whole, the results confirm the thermal properties derived from the Mariner 6 and 7 radiometers, although the temperatures, on the average, were cooler and shifted with respect to the Martian day during the dust storm. Thermal inertias and radiometric albedos were derived for many areas; no clear correlation exists between these properties. Thermal structure again was found at the spatial limit of the radiometer; no cases were found in which it was necessary to invoke internal heat sources

Generation of broad XUV continuous high harmonic spectra and isolated attosecond pulses with intense mid-infrared lasers

We present experimental results showing the appearance of a near-continuum in the high-order harmonic generation (HHG) spectra of atomic and molecular species as the driving laser intensity of an infrared pulse increases. Detailed macroscopic simulations reveal that these near-continuum spectra are capable of producing IAPs in the far field if a proper spatial filter is applied. Further, our simulations show that the near-continuum spectra and the IAPs are a product of strong temporal and spatial reshaping (blue shift and defocusing) of the driving field. This offers a possibility of producing IAPs with a broad range of photon energy, including plateau harmonics, by mid-IR laser pulses even without carrier-envelope phase stabilization.Comment: 7 pages, 5 figures, submitted to J.Phys. B (Oct 2011

Estrogen dependent expression of the receptor tyrosine kinase axl in normal and malignant human breast

Summary Background: Axl, a member of a family of receptor tyrosine kinases characterized by an extracellular domain resembling cell adhesion molecules and an intracellular conserved tyrosine kinase domain has been reported to induce cell proliferation and transformation. In mice, axl is expressed in the normal mammary gland and over-expressed in aggressive mammary tumors. Patients and methods: We have investigated the expression of axl immunohistochemically in 23 normal human breast samples and in 111 consecutive breast carcinomas. Expression of axl was correlated with tumour characteristics (lymph node involvement, stage, grade) and immunohistochemical expression of ER, PR, Ki-67 and c-erbB-2. Results: In normal tissue, axl localizes to the membrane of breast epithelial cells. Axl protein shows membrane associated staining in high correlation (P = 0.004) with the expression of the estrogen receptor (ER). Axl expression was found in a subset of breast carcinomas and was also correlated with high significance (P < 0.0001) with the presence of ER. Conclusion: Our results suggest that axl may serve as a mediator of estrogen stimulation preventing the completion of the breast epithelial life cycle and that estrogen induced axl expression may give a survival signal to cancerous cells, preventing them from dying through apoptosi

Decidual memory T‐cell subsets and memory T‐cell stimulatory cytokines in early‐ and late‐onset preeclampsia

Problem: Preeclampsia is a major cause of fetal and maternal mortality and morbidity. Disturbed fetal-maternal immune tolerance, and therewith memory T cells, might be involved in its etiology. This study aims to give insight into memory T-cell populations and its associated cytokines in the decidual layers in early-onset preeclampsia (EO-PE) and late-onset preeclampsia (LO-PE). Method of Study: Lymphocytes were isolated from the decidua parietalis and basalis from EO-PE (n = 6), LO-PE (n = 8) and healthy (n = 15) pregnancies. CD4+ and CD8+ central- (CCR7+), effector- (CCR7−), tissue resident- (CD103+), and regulatory- (Foxp3+) memory cell (CD45RO+) populations and their activation status (CD69+) were analyzed using flow cytometry. qRT-PCR analysis was performed on decidua parietalis and basalis biopsies to detect mRNA expression of interferon-gamma, interleukin-1B, IL2, IL6, IL7, IL8, IL10, IL15, and IL23. Results: CD4+ central-memory (CM) cell proportions were lower in the decidua parietalis in LO-PE (P <.0001) and EO-PE (P <.01) compared to healthy pregnancies. CD8+ memory (P <.05) and CD8+ CM (P <.01) cell proportions were also lower in the decidua parietalis in EO-PE compared to healthy pregnancies. This was accompanied by higher IL15 (P <.05) and IL23 (P <.05) and lower IL7 (P <.05) mRNA expression in decidua basalis biopsies from EO-PE compared to healthy pregnancies, analyzed by qPCR. Conclusion: In conclusion, decidual memory T-cell proportions, their activation status, and associated cytokines are altered in preeclampsia and might therefore be involved in fetal-maternal immune tolerance and the pathophysiology of preeclampsia