11 |
The first self-replicating molecule and the origin of life / El origen de la vida y la primera molécula capaz de replicarse a sí mismaLaos, Roberto, Benner, Steven 25 September 2017 (has links)
El origen de la vida en la Tierra es una de las preguntas más difíciles presentadas a la ciencia. En los últimos 60 años, ha habido un progreso considerable en entender cómo moléculas relativamente sencillas, que son relevantes para la vida, pueden ser generadas espontáneamente o pueden llegar a la Tierra desde el espacio. Además, los análisis de la evolución de la historia de ácidos nucleicos, los cuales almacenan la información genética, apuntan a un ancestro común universal ya extinto. Los estudios del origen de la vida ofrecen muchas pistas que apuntan hacia un origen común, quizás no solo en el Tierra sino también en algún otro punto del sistema solar. Debido al largo tiempo transcurrido desde que la Tierra empezó a albergar vida, las pistas más antiguas de los primeros organismos se han perdido. Es muy poco probable encontrar exactamente cómo fue este primer organismo. Sin embargo, en los últimos años la biología sintética ha logrado progresar mucho en la modificación de biomoléculas, en particular, los ácidos nucleicos. Es posible que pronto podamos construir y comprender un sistema minimalista en el cual las moléculas puedan copiarse a sí mismas dentro de una célula rudimentaria. El estudio de un sistema así podría permitirnos develar el origen de los primeros organismos. / The origin of life on Earth is one of the most challenging questions in science. In the last 60 years, considerable progress has been made in understanding how simple molecules relevant to life can be generated spontaneously or are known to arrive to Earth from space. Additionally, analysis of the evolution history of nucleic acids, which are the repository of genetic information, points to a now extinct, universal common ancestor for all life on Earth. The studies of the origin of life offer many clues towards a common origin, perhaps not just on Earth but somewhere else in the solar system. However due to the length of time that the Earth has harbored life, the oldest clues of the first organisms are mostly gone. It is unlikely to find exactly what this first organism was like. Nevertheless, in the last few years, synthetic biology has made remarkable progress at modifying biomolecules, particularly nucleic acids. It is possible that soon we will be able to construct and understand a minimalistic system in which molecules can copy themselves in a protocell. The study of such systems could shed light into the origin of the first organisms.
|
12 |
North Korea, representation and armament: an investigation into the politics of missile defenseChlumecky, Nicholas 30 April 2018 (has links)
This thesis examines how corporations use North Korea’s media portrayal to profit. By gaining government contracts to develop weapons and missile defense systems, companies such as Lockheed Martin make billions of dollars. The thesis will examine how this is accomplished in three stages: first, by examining how soft power is generated and used to build a consensus. Then, government usage of soft power to rationalize North Korea as a threat is discussed. Finally, how corporations profit from government-authorized weapons programs will be detailed. The thesis will incorporate theory based off of the ideas of Joseph Nye, as well as geopolitical concepts promulgated by Michael Hardt. / Graduate
|
13 |
A Smarter AntennaGuadiana, Juan, Macias, Fil, Braun, Chris 10 1900 (has links)
ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / The Isotropic radiator, a device capable of radiating energy evenly in all directions is an abstraction, itsʼ real counterpart is called an omnidirectional (omni) antenna. The omnidirectional antenna is found on many vehicles. Ideally, only one receiving system is ever needed to acquire an omni, no matter the vehicle orientation, given the range is not excessive. There are trade-offs with antenna efficiency, with gain typically around -15 dBi (95% coverage). This paper proposes abandoning this paradigm. If a vehicle knows where the ground is why radiate energy up into the sky, where there are no receiving stations. This can be achieved by integrating some instrumentation with a discrete antenna array so that it radiates only from selected elements. The accuracy required is modest, an inexpensive Inertial Measurement Unit (IMU) is sufficient to improve link margin by 10, 20dB or more. These numbers are credible, as outlandish as they are, and substantiated in this paper. Ironically, from the ground this non-isotropic antenna looks very isotropic. Of significant benefit, this Smarter Antenna concept enables spatial discrimination and with that comes spectrum efficiency gains beyond that achieved by other means including advanced modulation formats.
|
14 |
A high sensitivity imaging detector for the study of the formation of (anti)hydrogenBerggren, Karl January 2013 (has links)
AEGIS (Antimatter Experiment, Gravity, Interferometry and Spectroscopy) isan experiment under development at CERN which will measure earth's gravitationalforce on antimatter. This will be done by creating a horizontal pulsedbeam of low energy antihydrogen, an atom consisting of an antiproton anda positron. The experiment will measure the vertical de ection of the beamthrough which it is possible to calculate the gravitational constant for antimatter.To characterise the production process in the current state of the experimentit is necessary to develop an imaging detector for single excited hydrogenatoms. This thesis covers the design phase of that detector and includes studiesand tests of detector components. Following literature studies, tests and havingdiscarded several potential designs, a baseline design was chosen. The suggesteddetector will contain a set of ionising rings followed by an electron multiplyingmicrochannel plate, a light emitting phosphor screen, a lens system and nallya CCD camera for readout. The detector will be able to detect single hydrogenatoms, measure their time of ight as well as being able to image electronplasmas and measure the time of ight of the initial particles in such a plasma.Tests were made to determine the behaviour of microchannel plates at the lowtemperatures used in the experiment. Especially, the resistance and multiplicationfactor of the microchannel plates have been measured at temperaturesdown to 14 K. / AEGIS
|
15 |
Manipulation of positron plasma using the AEgIS system at CERNForslund, Ola Kenji January 2015 (has links)
AEgIS is an experiment at CERN where the goal is to directly measure the gravitational force on antimatter by producing antihydrogen. The antihydrogen will be produced by a charge exchange reaction using laser excited positronium and cold antiprotons. Having a well-characterized positron plasma with at least 108 positrons and knowing how it can be controlled is essential for the positronium production. This thesis is based on the goals of AEgIS experiment and describes the positron plasma manipulations being used in AEgIS in order to achieve the required plasma properties for the experiment. The positron system is made up by a source, a Surko trap and a Penning-Malmberg trap. This system was first optimized to increase the number of positrons. The plasma was then moved to the main traps of the experiment where it was systematically characterized in terms of lifetime, cooling efficiency and compression. Positron plasma compression in time, trapping and cooling was tested for the first time in AEgIS using a buncher and Penning-Malmberg traps respectively. In this thesis, it is shown that a compression of more than 50 % in time of the positron cloud using a buncher can be achieved. It is also shown that trapping and cooling with an efficiency of nearly 100 % in the main traps using a “V” shaped potential trap was successful. On top of that, the lifetime inside this “V” shaped potential trap was observed to be longer than 30 minutes.
|
16 |
MikrokurseWeiß, R., Kobel, M., Quast, G., Unkelbach, T. 05 October 2021 (has links)
In den Lehrplänen einiger Bundesländer gibt es noch keinen eigenständigen Themenbereich Teilchenphysik. Für diesen Fall sind die hier vorgestellten Mikrokurse zusammengestellt worden. Alle Kurse schlagen auf originelle Weise eine Brücke von klassischen Lehrplanthemen zu aktuellen Forschungsgegenständen. Denn viele der im Physikunterricht behandelten Themen lassen sich leicht um einen Bezug zur modernen Physik und insbesondere der Teilchenphysik ergänzen. Der zeitliche Bedarf für die Behandlung eines Kurses beträgt ca. ein bis zwei Unterrichtsstunden. Vorkenntnisse zur Teilchenphysik sind kaum notwendig. Die Mikrokurse können und sollen deshalb auch gerade dort eingesetzt werden, wo nur wenig Zeit zur Verfügung steht oder das Thema Teilchenphysik nicht im Lehrplan verankert ist. Zu jedem Kurs werden Einsatzmöglichkeiten und wünschenswerte Vorkenntnisse der Schüler:innen angegeben. Auf mögliche Erweiterungen und Vertiefungen wird hingewiesen.
|
17 |
Autonomous agent-based simulation of an AEGIS Cruiser combat information center performing battle air-defense commander operationsCalfee, Sharif H. 03 1900 (has links)
The AEGIS Cruiser Air-Defense Simulation is a program that models the operations of a Combat Information Center (CIC) team performing the ADC duties in a battle group using Multi-Agent System (MAS) technology implemented in the Java programming language. Set in the Arabian Gulf region, the simulation is a top-view, dynamic, graphics-driven software implementation that provides a picture of the CIC team grappling with a challenging, complex problem. Conceived primarily as a system to assist ships, waterfront training teams, and battle group staffs in ADC training and doctrine formulation, the simulation was designed to gain insight and understanding into the numerous factors (skills, experience, fatigue, aircraft numbers, weather, etc.) that influence the performance of the overall CIC team and watchstanders. The program explores the team's performance under abnormal or high intensity/stress situations by simulating their mental processes, decision-making aspects, communications patterns, and cognitive attributes. Everything in the scenario is logged, which allows for the reconstruction of interesting events (i.e. watchstander mistakes, chain-of-error analysis) for use in post-scenario training as well as the creation of new, more focused themes for actual CIC team scenarios. The simulation also tracks various watchstander and CIC team performance metrics for review by the user. / Lieutenant, United States Navy
|
18 |
Protein directed evolutionLaos, Roberto 25 September 2017 (has links)
Evolución dirigida de proteínas: La evolución dirigida es una técnica que nos permite explorar funciones enzimáticas que no son requeridas en el ambiente natural. Esta técnica, simula procesos genéticos naturales y de selección. Esta estrategia se utiliza cuando un diseño racional es muy complicado. Consiste en una repetición de ciclos de diversificación y selección que llevan a la acumulación de mutaciones benéficas. Aquí se presenta dos ejemplos de evolución dirigida con los cuales se ha trabajado directamente: la ADN polimerasa del organismo Thermus aquaticus usada comúnmente en PCR, y la proteína LacI que regula la expresión de genes usados para el metabolismo de lactosa en E. Coli. / Directed evolution allows us to explore protein functionalities not required in the natural environment. It mimics natural genetic processes and selective pressures. This approach is used when the molecular basis is not completely understood and rational design is a difficult task. This approach consists of serial cycles of consecutive diversification and selection which eventually lead to the accumulation of beneficial mutations. Here are presented two cases where directed evolution is used to modify two different proteins: Taq polymerase, enzyme used for DNA extension in PCR, and the LacI repressor protein which regulates gene expression on E.coli.
|
19 |
In pursuit of a perfect system : Balancing usability and security in computer system developmentMatras, Omolara January 2015 (has links)
Our society is dependent on information and the different technologies and artifacts that gives us access to it. However, the technologies we have come to depend on in different aspects of our lives are imperfect and during the past decade, these imperfections have been the target of identity thieves, cyber criminals and malicious persons within and outside the organization. These malicious persons often target networks of organizations such as hospitals, banks and other financial organizations. Access to these networks are often gained by sidestepping security mechanisms of computer-systems connected to the organization’s network. Often, the goal of computer-systems security mechanisms is to prevent or detect threats; or recover from an eventual attack. However, despite huge investments in IT-security infrastructure and Information security, over 95% of banks, hospitals and government agencies have at least 10 malicious infections bypass existing security mechanisms and enter their network without being detected. This has resulted in the loss of valuable information and substantial sums of money from banks and other organizations across the globe. From early research in this area, it has been discovered that the reason why security mechanisms fail is because it is often used incorrectly or not used at all. Specifically, most users find the security mechanisms on their computers too complicated and they would rather not use it. Therefore, previous research have focused on making computer-systems security usable or simplifying security technology so that they are “less complicated” for all types users, instead of designing computers that are both usable and secure. The problem with this traditional approach is that security is treated as an “add-on” to a finished computer-system design. This study is an attempt to change the traditional approach by adjusting two phases of a computer-system design model to incorporate the collection of usability as well as security requirements. Guided by the exploratory case study research design, I gained new insights into a situation that has shocked security specialists and organizational actors alike. This study resulted in the creation of a methodology for designing usable and secure computer-systems. Although this method is in its rudimentary stage, it was tested using an online questionnaire. Data from the literature study was sorted using a synthesis matrix; and analyzed using qualitative content analysis. Some prominent design and security models and methodologies discussed in this report include User-Centered System Design (UCSD), Appropriate and Effective Guidance for Information Security (AEGIS) and Octave Allegro. / Vårt samhälle är beroende av information och olika tekniker och artefakter som ger oss tillgång till den. Men tekniken vi förlitar oss på i olika aspekter av våra liv är ofullkomliga och under det senaste decenniet, har dessa brister varit föremål för identitetstjuvar, cyberbrottslingar och illvilliga personer inom och utanför organisationen. Dessa illvilliga personer riktar ofta sig till nätverk av organisationer såsom sjukhus, banker och andra finansiella organisationer. Tillgång till dessa nätverk uppnås genom att kringgå säkerhetsmekanismer av datorsystem anslutna till organisationens nätverk. Målet med datorsystemsäkerhet är att förhindra eller upptäcka hot; eller återhämta sig från eventuella attacker. Trots stora investeringar i IT-säkerhet infrastruktur och informationssäkerhet, över 95 % av banker, sjukhus och myndigheter har minst 10 skadliga infektioner kringgå befintliga säkerhetsmekanismer och träda in i sitt nätverk utan att upptäckas. Detta har lett till förlust av värdefulla informationer och stora summor av pengar från banker och andra organisationer över hela världen. Från tidigare forskning inom detta område, har det visat sig att anledningen till att säkerhetsmekanismer misslyckas beror ofta på att den används på ett felaktigt sätt eller används inte alls. I synnerhet menar de flesta användare att säkerhetsmekanismer på sina datorer är alltför komplicerat. Därför har tidigare forskning fokuserat på att göra datorsystemsäkerhet användbar så att den är "mindre komplicerat" för alla typer av användare, i stället för att designa datorer som både är användbara och säkra. Problemet med detta traditionella synsätt är att säkerheten behandlas som ett "tillägg" till en färdig datorsystemdesign. Denna studie är ett försök att ändra det traditionella synsättet genom att justera två faser av en datorsystemdesign modell för att integrera insamlingen av användbarhets- samt säkerhetskrav. Styrd av den explorativ fallstudie forskningsdesignen, fick jag nya insikter i en situation som har gäckat säkerhetsspecialister och organisatoriska aktörer. Denna studie resulterade i skapande av en designmetodik för användbara och säkra datorsystem. Även om denna metod är ännu i sin rudimentära fas, testades den med hjälp av en webbenkät. Data från litteraturstudien sorterades med hjälp av en syntesmatris; och analyserades med kvalitativ innehållsanalys. Några framstående design- och säkerhetsmodeller samt metoder som diskuterades i denna uppsats inkludera Användarcentrerad System Design (UCSD), Ändamålsenligt och Effektivt Vägledning för Informationssäkerhet (AEGIS) och Octave Allegro.
|
20 |
Planning concepts to sustain, develop, and test complex naval combat systems at the Surface Combat Systems Center, Wallops Island, VirginiaAbell, Barry J. 03 1900 (has links)
Approved for public release, distribution is unlimited / The Surface Combat Systems Center (SCSC), Wallops Island, Virginia is a combination of personnel, geography, airspace, and technology located on a barrier island off Virginia's Eastern Shore. First opened in 1985 as a US Navy, AEGIS Land-Based Test Site (LBTS), SCSC has grown to include the Ship Self Defense (SSD), and DD(X) combat system facilities to the site. SCSC is chartered to support computer program development, life cycle and in-service engineering, team training, and research, development, test, and evaluation services while adapting to evolution of US Naval combatants and emerging requirements. The purpose of this document is to present an analysis of existing US Navy shipboard and land-based organization business practices and apply them to the existing SCSC command organization. The objective is to combine US Navy transformation concepts and SCSC planning concepts to provide the documentation needed to support the development of new strategic business plans for the command. The goal is to provide a long-term strategy to transform SCSC into the US Navy's East Coast Weapons Range Facility or otherwise named, the Wallops Island Test and Evaluation Range Facility (WITERF), while maintaining its synergy as a LBTS for research, development, testing and evaluation of naval combat systems. / Civilian, United States Navy
|
Page generated in 0.024 seconds