Transcription of brain natriuretic peptide and atrial natriuretic peptide genes in human tissues

We have compared the expression of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) genes in various human tissues using a quantitative polymerase chain reaction technique. Tissues of three human subjects, obtained at autopsy, were analyzed. BNP transcripts could be detected in the central nervous system, lung, thyroid, adrenal, kidney, spleen, small intestine, ovary, uterus, and striated muscle. ANP transcripts could also be demonstrated in various human extracardiac tissues including several endocrine organs. In all peripheral tissues, the level of both natriuretic peptide transcripts was approximately 1-2 orders of magnitude lower than in cardiac ventricular tissues. This distribution is in marked contrast to the much lower level of ANP and BNP transcripts present in extracardiac rat tissues (generally less than 1/1000 of ventricles). These data suggest differential expression of the two natriuretic peptide genes in cardiac and extracardiac tissues in man. Furthermore, the presence of local synthesis of ANP and BNP in various peripheral organs suggests paracrine and/or autocrine function of these natriuretic peptides

Counting handovers in a cellular mobile communication network : delayed renewal process approach

Knowing the number of handovers that a user makes during a call session is particularly important in cellular mobile communication networks in order to make appropriate dimensioning of virtual circuits for wireless cells. In this paper, we study the probability distributions and statistical moments for thenumber of handovers per call for a variety of combinations of the call holding time (CHT) and cell residence time (CRT) distributions. We assume a mixed platform environment, which means that the first CRT in the originating cellhas different statistics from the CRTs in the subsequent cells. In particular, we consider circular cells. Based on the formulation in terms of delayed renewal processes, we obtain analytical expressions for the probability mass functions and moments of the handover number distribution.Includes bibliographical reference

Symmetry breaking in small rotating cloud of trapped ultracold Bose atoms

We study the signatures of rotational and phase symmetry breaking in small rotating clouds of trapped ultracold Bose atoms by looking at rigorously defined condensate wave function. Rotational symmetry breaking occurs in narrow frequency windows, where the ground state of the system has degenerated with respect to the total angular momentum, and it leads to a complex wave function that exhibits vortices clearly seen as holes in the density, as well as characteristic vorticity. Phase symmetry (or gauge symmetry) breaking, on the other hand, is clearly manifested in the interference of two independent rotating clouds.Comment: 4 pages, 2 figure

Ordered structures in rotating ultracold Bose gases

The characterization of small samples of cold bosonic atoms in rotating microtraps has recently attracted increasing interest due to the possibility to deal with a few number of particles per site in optical lattices. We analyze the evolution of ground state structures as the rotational frequency $\Omega$ increases. Various kinds of ordered structures are observed. For $N<10$ atoms, the standard scenario, valid for large sytems, is absent, and only gradually recovered as $N$ increases. The vortex contribution to the total angular momentum $L$ as a function of $\Omega$ ceases to be an increasing function of $\Omega$, as observed in experiments of Chevy {\it et al.} (Phys. Rev. Lett. 85, 2223 (2000)). Instead, for small $N$, it exhibits a sequence of peaks showing wide minima at the values of $\Omega$, where no vortices appear.Comment: 35 pages, 17 figure

Counting handovers in a cellular mobile communication network : equilibrium renewal process approach

Knowing the number of handovers that a user makes during a call session is particularly important in wireless cellular mobile communication networks in order to make appropriate dimensioning of virtual circuits for wireless cells. In this paper, we study the probability distributions and statistical moments for the number of handovers per call for a variety of combinations of the call holding time (CHT) and cell residence time (CRT) distributions. Based on the formulation in terms of equilibrium renewal processes, we obtain analytical expressions for the probabilitymass functions and moments of the handover number distribution. Numerical examples are provided that show a heavy-tail in the handover number distributionwhen the CHT has heavy tail.Includes bibliographical reference

Vortex nucleation in mesoscopic Bose superfluid and breaking of the parity symmetry

We analyze vortex nucleation in mezoscopic 2D Bose superfluid in a rotating trap. We explicitly include a weakly anisotropic stirring potential, breaking thus explicitly the axial symmetry. As the rotation frequency passes the critical value $\Omega_c$ the system undergoes an extra symmetry change/breaking. Well below $\Omega_c$ the ground state is properly described by the mean field theory with an even condensate wave function. Well above $\Omega_c$ the MF solution works also well, but the order parameter becomes odd. This phenomenon involves therefore a discrete parity symmetry breaking. In the critical region the MF solutions exhibit dynamical instability. The true many body state is a strongly correlated entangled state involving two macroscopically occupied modes (eigenstates of the single particle density operator). We characterize this state in various aspects: i) the eligibility for adiabatic evolution; ii) its analytical approximation given by the maximally entangled combination of two single modes; and finally iii) its appearance in particle detection measurements.Comment: 14 pages, 27 figure

Dynamic mobility management for cellular networks : a delayed renewal process approach

Tracking mobile users in cellular wireless networks involves two basic functions: location update and paging. Location update refers to the process of tracking the location of mobile users that are not in conversation. Three basic algorithms have been proposed in the literature, namely the distance-based, time-based, and movement-based algorithms. The problem of minimizing the location update and paging costs has been solved in the literature by considering exponentially distributed Cell Residence Times (CRT) and Inter-Call Time (ICT), which is the time interval between two consecutive phone calls. In this paper we have selected the movement-based scheme since it is effective and easy to implement. Applying the theory for the delayed renewal process, we find the distribution of the number of cell crossings when the ICT is a mixtuer of exponentially distributed r.v.\u27s and the CRT comes from any distribution with Laplace-Stieltjes transform. In particular, we consider the case in which the first CRT may have a different distribution from the remaining CRT\u27s, which includes the case of circular cells. We aim at the total cost minimization in this case.Includes bibliographical references (p. 10

Structural models of the different trimers present in the core of phycobilisomes from <i>Gracilaria chilensis</i> based on crystal structures and sequences

Phycobilisomes (PBS) are accessory light harvesting protein complexes that directionally transfer energy towards photosystems. Phycobilisomes are organized in a central core and rods radiating from it. Components of phycobilisomes in Gracilaria chilensis (Gch) are Phycobiliproteins (PBPs), Phycoerythrin (PE), and Phycocyanin (PC) in the rods, while Allophycocyanin (APC) is found in the core, and linker proteins (L). The function of such complexes depends on the structure of each component and their interaction. The core of PBS from cyanobacteria is mainly composed by cylinders of trimers of α and β subunits forming heterodimers of Allophycocyanin, and other components of the core including subunits αII and β18. As for the linkers, Linker core (LC) and Linker core membrane (LCM) are essential for the final emission towards photoreaction centers. Since we have previously focused our studies on the rods of the PBS, in the present article we investigated the components of the core in the phycobilisome from the eukaryotic algae, Gracilaria chilensis and their organization into trimers. Transmission electron microscopy provided the information for a three cylinders core, while the three dimensional structure of Allophycocyanin purified from Gch was determined by X-ray diffraction method and the biological unit was determined as a trimer by size exclusion chromatography. The protein sequences of all the components of the core were obtained by sequencing the corresponding genes and their expression confirmed by transcriptomic analysis. These subunits have seldom been reported in red algae, but not in Gracilaria chilensis. The subunits not present in the crystallographic structure were modeled to build the different composition of trimers. This article proposes structural models for the different types of trimers present in the core of phycobilisomes of Gch as a first step towards the final model for energy transfer in this system

Vortex nucleation as a case study of symmetry breaking in quantum systems

Mean-field methods are a very powerful tool for investigating weakly interacting many-body systems in many branches of physics. In particular, they describe with excellent accuracy trapped Bose-Einstein condensates. A generic, but difficult question concerns the relation between the symmetry properties of the true many-body state and its mean-field approximation. Here, we address this question by considering, theoretically, vortex nucleation in a rotating Bose-Einstein condensate. A slow sweep of the rotation frequency changes the state of the system from being at rest to the one containing one vortex. Within the mean-field framework, the jump in symmetry occurs through a turbulent phase around a certain critical frequency. The exact many-body ground state at the critical frequency exhibits strong correlations and entanglement. We believe that this constitutes a paradigm example of symmetry breaking in - or change of the order parameter of - quantum many-body systems in the course of adiabatic evolution.Comment: Minor change