6,920 research outputs found

### Teleportation Topology

We discuss the structure of teleportation. By associating matrices to the
preparation and measurement states, we show that for a unitary transformation M
there is a full teleportation procedure for obtaining M|S> from a given state
|S>. The key to this construction is a diagrammatic intepretation of matrix
multiplication that applies equally well to a topological composition of a
maximum and a minimum that underlies the structure of the teleportation. This
paper is a preliminary report on joint work with H. Carteret and S. Lomonaco.Comment: LaTeX document, 16 pages, 8 figures, Talk delivered at the Xth
International Conference on Quantum Optics, Minsk, Belaru

### Are Dark Energy and Dark Matter Different Aspects of the Same Physical Process?

It is suggested that the apparently disparate cosmological phenomena
attributed to so-called 'dark matter' and 'dark energy' arise from the same
fundamental physical process: the emergence, from the quantum level, of
spacetime itself. This creation of spacetime results in metric expansion around
mass points in addition to the usual curvature due to stress-energy sources of
the gravitational field. A recent modification of Einstein's theory of general
relativity by Chadwick, Hodgkinson, and McDonald incorporating spacetime
expansion around mass points, which accounts well for the observed galactic
rotation curves, is adduced in support of the proposal. Recent observational
evidence corroborates a prediction of the model that the apparent amount of
'dark matter' increases with the age of the universe. In addition, the proposal
leads to the same result for the small but nonvanishing cosmological constant,
related to 'dark energy, as that of the causet model of Sorkin et al.Comment: Some typos corrected. Comments welcome, pro or co

### The computational complexity of Kauffman nets and the P versus NP problem

Complexity theory as practiced by physicists and computational complexity
theory as practiced by computer scientists both characterize how difficult it
is to solve complex problems. Here it is shown that the parameters of a
specific model can be adjusted so that the problem of finding its global energy
minimum is extremely sensitive to small changes in the problem statement. This
result has implications not only for studies of the physics of random systems
but may also lead to new strategies for resolving the well-known P versus NP
question in computational complexity theory.Comment: 4 pages, no figure

### Phase transition in a class of non-linear random networks

We discuss the complex dynamics of a non-linear random networks model, as a
function of the connectivity k between the elements of the network. We show
that this class of networks exhibit an order-chaos phase transition for a
critical connectivity k = 2. Also, we show that both, pairwise correlation and
complexity measures are maximized in dynamically critical networks. These
results are in good agreement with the previously reported studies on random
Boolean networks and random threshold networks, and show once again that
critical networks provide an optimal coordination of diverse behavior.Comment: 9 pages, 3 figures, revised versio

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### The Role of the Brain in the Pathogenesis and Physiology of Polycystic Ovary Syndrome (PCOS).

Polycystic ovary syndrome (PCOS) is a common reproductive endocrine disorder, affecting at least 10% of women of reproductive age. PCOS is typically characterized by the presence of at least two of the three cardinal features of hyperandrogenemia (high circulating androgen levels), oligo- or anovulation, and cystic ovaries. Hyperandrogenemia increases the severity of the condition and is driven by increased luteinizing hormone (LH) pulse secretion from the pituitary. Indeed, PCOS women display both elevated mean LH levels, as well as an elevated frequency of LH pulsatile secretion. The abnormally high LH pulse frequency, reflective of a hyperactive gonadotropin-releasing hormone (GnRH) neural circuit, suggests a neuroendocrine basis to either the etiology or phenotype of PCOS. Several studies in preclinical animal models of PCOS have demonstrated alterations in GnRH neurons and their upstream afferent neuronal circuits. Some rodent PCOS models have demonstrated an increase in GnRH neuron activity that correlates with an increase in stimulatory GABAergic innervation and postsynaptic currents onto GnRH neurons. Additional studies have identified robust increases in hypothalamic levels of kisspeptin, another potent stimulator of GnRH neurons. This review outlines the different brain and neuroendocrine changes in the reproductive axis observed in PCOS animal models, discusses how they might contribute to either the etiology or adult phenotype of PCOS, and considers parallel findings in PCOS women

### The Number of Different Binary Functions Generated by NK-Kauffman Networks and the Emergence of Genetic Robustness

We determine the average number $\vartheta (N, K)$, of \textit{NK}-Kauffman
networks that give rise to the same binary function. We show that, for $N \gg
1$, there exists a connectivity critical value $K_c$ such that $\vartheta(N,K) \approx e^{\phi N}$ ($\phi > 0$) for $K < K_c$ and
$\vartheta(N,K) \approx 1$ for $K > K_c$. We find that $K_c$ is not a
constant, but scales very slowly with $N$, as $K_c \approx \log_2 \log_2 (2N
/ \ln 2)$. The problem of genetic robustness emerges as a statistical property
of the ensemble of \textit{NK}-Kauffman networks and impose tight constraints
in the average number of epistatic interactions that the genotype-phenotype map
can have.Comment: 4 figures 18 page

### On the number of attractors in random Boolean networks

The evaluation of the number of attractors in Kauffman networks by Samuelsson
and Troein is generalized to critical networks with one input per node and to
networks with two inputs per node and different probability distributions for
update functions. A connection is made between the terms occurring in the
calculation and between the more graphic concepts of frozen, nonfrozen and
relevant nodes, and relevant components. Based on this understanding, a
phenomenological argument is given that reproduces the dependence of the
attractor numbers on system size.Comment: 6 page

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