According to the library model, related species can have in common satellite DNA (satDNA) families amplified in differing abundances, but reasons for persistence of particular sequences in the library during long periods of time are poorly understood. In this paper, we characterize 3 related satDNAs coexisting in the form of a library in mitotic parthenogenetic root-knot nematodes of the genus ...

We introduce a probabilistic approach to the problem of counting dwarf satellites around host galaxies in databases with limited redshift information. This technique is used to investigate the occurrence of satellites with luminosities similar to the Magellanic Clouds around hosts with properties similar to the Milky Way (MW) in the object catalog of the Sloan Digital Sky Survey (SDSS). Our ana...

Stand-alone Global Navigation Satellites System (GNSS) can provide a very accurate real-time positioning in good visibilty and signals conditions. Unfortunately, for a vehicle evolving in urban areas, those conditions are rarely satisfied, leading to debased computed location or lack of solution if less than four SVs are visible. A way to tackle such a problem can consist in fusing the raw meas...

In this paper, we discuss on two important issues through the realization of global personal communication networks with low earth orbital (LEO) satellites. The first issue is the selection of an effective multiple access scheme which can utilize the limited spectrum allocated to these systems. In this way, we focus on the schemes based on spread spectrum techniques and explain their unique cha...

The Namuru family of Field Programmable Gate Array (FPGA)-based GNSS receivers now includes a space-qualified design designated the Namuru V3.2A. This GPS L1 carrier phase receiver is suitable for low earth orbit (LEO) “cube” satellites. Actel flash-based FPGA’s are used along with latch-up detection circuitry and other standard techniques to provide resilience to the effects of radiation. The ...

Recent observations show that the number of stars with very low metallicities in the dwarf spheroidal satellites of the Milky Way is low, despite the low average metallicities of stars in these systems. We undertake numerical simulations of star formation and metal enrichment of dwarf galaxies in order to verify whether this result can be reproduced with “standard” assumptions. The answer is li...

We investigate the distribution of luminous satellite galaxies with respect to the symmetry axes of isolated host galaxies in a ΛCDM universe. The selection of “host” and “satellite” samples based upon three somewhat different algorithms, all of which yield nearly identical results. In projection on the sky, the satellites are located preferentially close to the major axes of the host halos, re...

the space environment consists mainly of high-energy charged particles, such as protons, electrons and heavy ions. they are originating from several sources including galactic cosmic radiation, solar flares and van allen belts. high energy electromagnetic radiation and neutrons have also been measured on spacecraft. although shielding can reduce the effect of space radiation it cannot be elimin...

This study focuses on the development of a precise attitude control system for small satellites. In general, conventional methods used for attitude control in standard-sized satellites are not applicable to small satellites because of constraints of power consumption, space requirements, and mass. In addition, small satellites are more greatly affected than standard-sized satellites by attitude...