4,908 research outputs found

    Comparative analysis of copyright assignment and licence formalities for Open Source Contributor Agreements

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    This article discusses formal requirements in open source software contributor copyright assignment and licensing agreements. Contributor agreements are contracts by which software developers transfer or license their work on behalf of an open source project. This is done for convenience and enforcement purposes, and usually takes the form of a formal contract. This work conducts a comparative analysis of how several jurisdicitons regard those agreements. We specifically look at the formal requirements across those countries to ascertain whether formalities are constitutive or probative. We then look at the consequences of the lack of formalities for the validity of those contributor agreements

    The Effects of climate change on basic animal cell functions

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    Increasing global temperatures during the 21st century may have detrimental effects on basic cell functions within ectothermal animals. This project aims to systematically examine the effects of climate change on secretory cargo localization through the analysis of Rab Proteins found in the model organism Drosophila melanogaster. Rab Proteins play an essential role in vesicular transport within the cell and can be genetically manipulated to monitor the biological consequences of global warming

    The Role of an ABC transporter as a steroid antagonist in Drosophila

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    Drosophila melanogaster are holometabolous insects that have several distinct life stages including larvae and a winged adult. The larval stage is mainly a time of feeding and growth, while the adult stage is optimized for sexual reproduction and dissemination. The larval stage can itself be divided into three time periods, or instars: 1st (L1), 2nd (L2), and 3rd (L3) (Figure 1). Larval growth – both between instars and beyond – depends on specific signaling pathways controlled by a cholesterol derived steroid, 20-hydroxyecdysone (20E). Although 20E is a systemic developmental signal, little is known about the molecular details of how different tissues respond to the hormone. We have been studying one gene induced by 20E in some target tissues [1]. This gene, E23, encodes an ATP binding cassette (ABC) transporter protein that may function to limit hormone exposure in tissues where it is expressed

    Eph and Ephrin Signaling in Mammary Gland Morphogenesis and Cancer

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    The Eph family of receptor tyrosine kinases and their membrane-bound ligands, the ephrins, play a central role in pattern formation during embryonic development and there is growing evidence that they are also instrumental in the control of tissue dynamics in the adult. The mammary gland is a paradigm for morphogenic processes occurring in the adult, since the gland develops predominantly postnatally and is subjected to continuous cyclic remodeling according to functional demands. Thus, pattern formation and the establishment of a functional organ structure are permanent themes in the mammary gland life cycle. In this paper we summarize the experimental evidence and discuss possible mechanisms by which Ephs and ephrins are modulating mammary epithelial cell adhesion, communication, and migration. Furthermore, we speculate on the different aspects of their influence on normal mammary gland development, function, and carcinogenesi

    Optical Communications and Sensor Demonstration

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    The Optical Communications and Sensor Demonstration (OCSD) project addresses two cross-cutting capabilities of value to many future small spacecraft missions: high-speed optical transmission of data and small spacecraft proximity operations. Optical data rates demonstrated by OCSD are expected to be 200 megabits persecond (Mbs) or higher, a factor of 100 increase over current high-end CubeSat communications systems. The proximity sensors developed for this mission enable relative position measurement between two small satellites - a capability not previously demonstrated

    Transcriptome Analysis of Glue Secretion in Drosophila

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    Steroid hormones control important developmental and physiological responses in animals, including humans. It is known that when a cell is exposed to a steroid hormone, there is an immediate change in the genes that are expressed into proteins. Of notable importance is steroid regulation in the salivary glands of larval Drosophila melanogaster and the corresponding physiological responses that are governed by treatment with the conserved insect steroid, 20-hydroxyecdysone (20E). Exposure to the steroid hormone 20E causes a change in gene expression that facilitates the secretion of glue glycoproteins from inside the cells into the lumen of the tissue. Altered gene expression induced from exposure to 20E is manifested in part because of an elevation in the cytoplasmic concentration of Calcium ions (Ca2+). The molecular details that make the connections between the observed secretions of glue granules, the sudden increase in intracellular Ca2+ concentration, and the proteins that modulate these physiological responses are unknown, but are now experimentally tractable because of recent advances in the fields of genomics and molecular genetics. We have conducted a search through a database containing over 13,000 expressed genes from the salivary glands that show altered expression before and after hormone exposure. The goal of this research is to compile a list of candidates that show a significantly altered level of expression in preparation for functional genetic tests. Any such genes identified will be compared to human databases for shared functionality in terms of their expression and subsequent control on basic physiological responses in mammalian systems

    Propulsion System and Orbit Maneuver Integration in CubeSats: Trajectory Control Strategies Using Micro Ion Propulsion

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    The Propulsion System and Orbit Maneuver Integration in CubeSats project aims to solve the challenges of integrating a micro electric propulsion system on a CubeSat in order to perform orbital maneuvers and control attitude. This represents a fundamentally new capability for CubeSats, which typically do not contain propulsion systems and cannot maneuver far beyond their initial orbits

    Nodes

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    Nodes is a technology demonstration mission that is scheduled for launch to the International SpaceStation no earlier than Nov.19, 2015. The two Nodes satellites will be deployed from the Station in early 2016 todemonstrate new network capabilities critical to the operation of swarms of spacecraft. They will demonstrate the ability ofmulti spacecraft swarms to receive and distribute ground commands, exchange information periodically, andautonomously configure the network by determining which spacecraft should communicate with the ground each day ofthe mission
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