Search results for "PROPAGATION"

Decoupled Downlink-Uplink Coverage Analysis with Interference Management for Enriched Heterogeneous Cellular Networks

2016

Heterogeneous cellular networks (HetCNets) offer a promising solution to cope with the current cellular coverage crunch. Due to the large transmit power disparity, while following maximum power received (MPR) association scheme, a larger number of users are associated with macro-cell BS (MBS) than small-cell BSs (SBSs). Therefore, an imbalance load arrangement takes place across the HetCNets. Hence, using cell range expansion-based cell association, we can balance the load across the congested MBS. However, using MPR association scheme, users’ offloading leads to two challenges: 1) macro-cell interference , in which the MBS interferes with the offloaded users, and 2) coupled downlink-uplink…

A comparative analysis of genetic variation in rootstocks and scions of old olive trees – a window into the history of olive cultivation practices an…

2014

Background Past clonal propagation of olive trees is intimately linked to grafting. However, evidence on grafting in ancient trees is scarce, and not much is known about the source of plant material used for rootstocks. Here, the Simple Sequence Repeat (SSR) marker technique was used to study genetic diversity of rootstocks and scions in ancient olive trees from the Levant and its implications for past cultivation of olives. Leaf samples were collected from tree canopies (scions) and shoots growing from the trunk base (suckers). A total of 310 trees were sampled in 32 groves and analyzed with 14 SSR markers. Results In 82.7% of the trees in which both scion and suckers could be genotyped, t…

Astrophysical constraints on extended gravity models

2015

We investigate the propagation of gravitational waves in the context of fourth order gravity nonminimally coupled to a massive scalar field. Using the damping of the orbital period of coalescing stellar binary systems, we impose constraints on the free parameters of extended gravity models. In particular, we find that the variation of the orbital period is a function of three mass scales which depend on the free parameters of the model under consideration; we can constrain these mass scales from current observational data.

Limits on neutrino Lorentz violation from multimessenger observations of TXS 0506+056

2019

The observation by the IceCube Collaboration of a high-energy ($E \gtrsim 200$ TeV) neutrino from the direction of the blazar TXS 0506+056 and the coincident observations of enhanced $\gamma$-ray emissions from the same object by MAGIC and other experiments can be used to set stringent constraints on Lorentz violation in the propagation of neutrinos that is linear in the neutrino energy: $\Delta v = - E/M_1$, where $\Delta v$ is the deviation from the velocity of light, and $M_1$ is an unknown high energy scale to be constrained by experiment. Allowing for a difference in neutrino and photon propagation times of $\sim 10$ days, we find that $M_1 \gtrsim 3 \times 10^{16}$ GeV. This improves …

On gravitational waves in Born-Infeld inspired non-singular cosmologies

2017

We study the evolution of gravitational waves for non-singular cosmological solutions within the framework of Born-Infeld inspired gravity theories, with special emphasis on the Eddington-inspired Born-Infeld theory. We review the existence of two types of non-singular cosmologies, namely bouncing and asymptotically Minkowski solutions, from a perspective that makes their features more apparent. We study in detail the propagation of gravitational waves near these non-singular solutions and carefully discuss the origin and severity of the instabilities and strong coupling problems that appear. We also investigate the role of the adiabatic sound speed of the matter sector in the regularisatio…

Multilevel model for flood wave propagation in flood-affected areas

1998

A hyperbolic model for the simulation of flood wave propagation on initially dry land is presented. The convective inertia terms are neglected in the momentum equations. This assumption allows the use of a finite element scheme with linear shape functions for the free surface elevations and constant unit discharges inside each element. An appropriate use of the explicit and implicit approximation of the spatial derivatives is able to avoid the introduction of internal boundaries in the case of vertical discontinuities of the terrain elevation. This is obtained without losing the desirable features of the system matrix or limiting the maximum Courant number. The efficiency and the reliabilit…

Bichromatic field propagation in a resonant medium: Floquet analysis

2011

We study the propagation of a bichromatic field in a resonant medium. The two modes of the incoming fields are pulsed and delayed with respect to each other. It is shown that in the course of the propagation, new Raman sidebands will be generated. The achievable frequency spacing between the sidebands is determined from experimental data. A numerical example is shown for realistic physical parameters.

Plug plant fertilization and planting density affect onion productivity in sicily

2009

The aim of this study was to evaluate the effects of different planting density and different levels of plug plant fertilization on onion production in Sicily. Onion landrace ‘Bisacquino’ was sown in the first week of January 2006 in a unheated greenhouse in polystyrene plug trays. Seedlings were fertigated with the following three different solutions containing (in mg l-1) 800 N - 400 P - 400 K, 1200 N - 600 P - 600 K or 1600 N- 800 P - 800 K. Trays were subirrigated with the nutrient solution both at one leaf stage and 10 days prior transplanting. Plug plants were field transplanted in the Sicilian hilly countryside. The plugs consisting of one, two, or three onion plants were set 20 cm a…

Propagation techniques for Iberis semperflorens L.

2009

Micropropagation ofAgeratum houstonianumby nodal segments

2017

Ageratum houstonianum is a bedding and flowering potted plant originated from Central America which is generally propagate by seed. In this report a preliminary in vitro technique for propagation of A. houstonianum was investigated. In vitro germinated seeds were used to establish aseptic shoot cultures of several clones. Seedling stem segments bearing 3-4 nodes were placed on Murashige and Skoog (MS) basal medium plus 20 g L-1 sucrose, 8.0 g L-1 Agar to induce axillary shoot development. Axillary shoots were subcultured into the same medium and nodal segments were sectioned and subcultured to increase the stock of shoot cultures. Shoot cultures of the selected clone AG14 were used to accom…