Construction of invisibility cloaks of arbitrary shape and size using planar layers of metamaterials

Transformation optics (TO) is a powerful tool for the design of electromagnetic and optical devices with novel functionality derived from the unusual properties of the transformation media. In general, the fabrication of TO media is challenging, requiring spatially varying material properties with both anisotropic electric and magnetic responses. Though metamaterials have been proposed as a path for achieving such complex media, the required properties arising from the most general transformations remain elusive, and cannot implemented by state-of-the-art fabrication techniques. Here, we propose faceted approximations of TO media of arbitrary shape in which the volume of the TO device is divided into flat metamaterial layers. These layers can be readily implemented by standard fabrication and stacking techniques. We illustrate our approximation approach for the specific example of a two-dimensional, omnidirectional "invisibility cloak", and quantify its performance using the total scattering cross section as a practical figure of merit. © 2012 American Institute of Physics.

Broadband electromagnetic cloaking with smart metamaterials.

The ability to render objects invisible with a cloak that fits all objects and sizes is a long-standing goal for optical devices. Invisibility devices demonstrated so far typically comprise a rigid structure wrapped around an object to which it is fitted. Here we demonstrate smart metamaterial cloaking, wherein the metamaterial device not only transforms electromagnetic fields to make an object invisible, but also acquires its properties automatically from its own elastic deformation. The demonstrated device is a ground-plane microwave cloak composed of an elastic metamaterial with a broad operational band (10-12 GHz) and nearly lossless electromagnetic properties. The metamaterial is uniform, or perfectly periodic, in its undeformed state and acquires the necessary gradient-index profile, mimicking a quasi-conformal transformation, naturally from a boundary load. This easy-to-fabricate hybrid elasto-electromagnetic metamaterial opens the door to implementations of a variety of transformation optics devices based on quasi-conformal maps.

Low-loss directional cloaks without superluminal velocity or magnetic response.

The possibility of making an optically large (many wavelengths in diameter) object appear invisible has been a subject of many recent studies. Exact invisibility scenarios for large (relative to the wavelength) objects involve (meta)materials with superluminal phase velocity [refractive index (RI) less than unity] and/or magnetic response. We introduce a new approximation applicable to certain device geometries in the eikonal limit: piecewise-uniform scaling of the RI. This transformation preserves the ray trajectories but leads to a uniform phase delay. We show how to take advantage of phase delays to achieve a limited (directional and wavelength-dependent) form of invisibility that does not require loss-ridden (meta)materials with superluminal phase velocities.

The origins of the control of information in war coverage

The conflict’s coverage, since its inception, has been closely linked to the relationship that both the military and the media have. The freedom they maintained during their first conflicts, although not without problems, though they suffered strict censorship suffered during World War I, and lastly the straitjacket treatment that they have endured during recent wars. The Vietnam War marked a turning point in this relationship, and after the invasion of Grenada, the military would launch new information guidelines, called Department of Defense National Media Pool. The lack of clear guidance of both control and space, has made for a complicated relationship between media and military, so the rules have evolved after every conflict shaping the future of press coverage and thus, war reporting.

Transit Observations of the Hot Jupiter HD 189733b at X-Ray Wavelengths

We present new X-ray observations obtained with Chandra ACIS-S of the HD 189733 system, consisting of a K-type star orbited by a transiting Hot Jupiter and an M-type stellar companion. We report a detection of the planetary transit in soft X-rays with a significantly deeper transit depth than observed in the optical. The X-ray data favor a transit depth of 6%-8%, versus a broadband optical transit depth of 2.41%. While we are able to exclude several possible stellar origins for this deep transit, additional observations will be necessary to fully exclude the possibility that coronal inhomogeneities influence the result. From the available data, we interpret the deep X-ray transit to be caused by a thin outer planetary atmosphere which is transparent at optical wavelengths, but dense enough to be opaque to X-rays. The X-ray radius appears to be larger than the radius observed at far-UV wavelengths, most likely due to high temperatures in the outer atmosphere at which hydrogen is mostly ionized. We furthermore detect the stellar companion HD 189733B in X-rays for the first time with an X-ray luminosity of log LX = 26.67 erg s-1. We show that the magnetic activity level of the companion is at odds with the activity level observed for the planet-hosting primary. The discrepancy may be caused by tidal interaction between the Hot Jupiter and its host star.

X-Ray Emission from the Super-Earth Host GJ 1214

Stellar activity can produce large amounts of high-energy radiation, which is absorbed by the planetary atmosphere leading to irradiation-driven mass loss. We present the detection and an investigation of high-energy emission in a transiting super-Earth host system, GJ 1214, based on XMM-Newton observations. We derive an X-ray luminosity of LX = 7.4 × 1025 erg s-1 and a corresponding activity level of log (LX /L bol) ~ -5.3. Further, we determine a coronal temperature of about ~3.5 MK, which is typical for coronal emission of moderately active low-mass stars. We estimate that GJ 1214 b evaporates at a rate of 1.3× 1010 g s-1 and has lost a total of ≈2-5.6 M ⊕.

Star-planet interactions and selection effects from planet detection methods

Planets may have effects on their host stars by tidal or magnetic interaction. Such star-planet interactions are thought to enhance the activity level of the host star. However, stellar activity also affects the sensitivity of planet detection methods. Samples of planet-hosting stars which are investigated for such star-planet interactions are therefore subject to strong selection effects which need to be taken into account.

Merrimack Intelligencer Vol. 5 No. 48

This was a weekly paper that was published every Saturday. The motto of the Merrimack was: "Not too rash--Yet not fearful--We aim to be just." It was published from 1808-1817. Topics of interest include: Page 1: State of New York Republicans published a statement arguing against the war and the policies of John Adams and James Madison; account of the capture of York by the Americans, 27 April 1813; Page 2: account of the capture of York by the Americans, 27 April 1813; letter from American Brig. Gen. Henry Miller to Sir John B. Warren warning the British not to execute captured U.S. citizen O'Neal; response from Sir John B. Warren to Brig. Gen. Henry Miller stating that O'Neal had been released; account of Stephen Girard buying back his ransomed ship from the British; Page 3: account of Stephen Girard buying back his ransomed ship from the British; U.S. General Harrison repels British and Indian forces that attack Fort Meigs; account of British forces capturing U.S. privateer ship Alexander; report of British forces near Newport, New York, the Delaware river, and the Potomac River; report of Indian attacks in Kaskaskia, Randolph County; report of a boat load of provisions attacked by Indians near Fort Harrison; Commodore Isaac Chauncey arrived at Sacket's Harbor to unload stores taken from York before leaving for Niagara to commence attack against Fort George; U.S. Army announcement recruiting men 18 to 45 years of age to enlist in the army;

Baltimore Patriot and Evening Advertiser Vol. 3 No. 89- April 15, 1814

This daily paper, except Sundays, began publication on August 17, 1813 and ceased April 30, 1817. It was also published tri-weekly for a "COUNTRY" edition. The paper later became the Baltimore Patriot. Topics of interest include: Page 1: announcement Capt. M. Simmones Burnbury is seeking men to form a company of Sea Fencibles; Page 2: U.S. Legislature authorizes bill to increase the Marine Corps; U.S. Legislature authorizes bill to purchase vessels captured on Lake Erie; U.S. Senate bill authorizes the appointment of officers for the flotilla service; President of United States authorized to accept service of volunteer corps for defence of United States; Letter from Capt. A. H. Holmes to Lieut. Col. Butler detailing an American victory over the British near Detroit; announcement of British forces building barges for the purpose of attacking Detroit; War sloop Erie returns to Baltimore unable to reach sea due to British forces in the Chesapeake; Page 3: Death notice of Mr. Ward Fairchild of the U.S. Army; Page 4: Commander of the U.S. Flotilla seeks men for the Chesapeake Flotilla.

Pro Bono Publico, poem, n.d.

The poem is unsigned and is not divided into stanzas. It mentions General Brock, General Dearborn, Sir Peregrine, Fort George and the militia men of Lincoln. General Isaac Brock was a British Army officer and administrator who was promoted to Major General. He was responsible for defending Upper Canada against the United States. He died at the Battle of Queenston Heights during the War of 1812. In 1812, Dearborn was in charge of the northeastern sector from Niagara to the New England coast in his role as senior Major General of the U.S. Army. Dearborn proved that he was neither psychologically nor physically fit enough to take control. He tried to persuade New England governors to allow their militia to be used to invade Canada. He was not successful in his quest and no major offensive was launched against Lower Canada. Sir Peregrine probably refers to Sir Peregrine Maitland who was appointed as the Lieutenant Governor of Upper Canada in 1818. Fort George is located in Niagara-on-the-Lake, Ontario. It was the site of several battles during the War of 1812. The Lincoln Militia fought in battles on the Niagara Peninsula and the eastern shores of the Niagara River in the War of 1812.

Neurotransmitter Functional Role in Neurodegenerative Diseases: human Health

Neuroscience is the study of'tbe ne rvous system , including the i - ; . in, spinal cord and peripheral nerves . Neurons are the basic cells of the brain and nervous system which exerts its functional role through various neurotransmitters and receptor systems . The activity of a nen ren depends on the balance between the number of excitatory and inhibito r y processes affecting it, both processes occurring individually and sin ,tlte-' ,ieously. The functional bal,ince of different neurotransmitters such as Acct >>lcholine (Ach), Dopamine (DA), Serotonin (5-1-17), Nor epinepbri,te (N.1 j, Epinephrine (LPI), Glutamate and Gamma amino butyric acid (GA BA) regulates the growth , division and other vital functions ofa normal cell / organisin (Sudha, 1 998). The micro-environ ; nertt of the cell is controlled / the macro-environment that surrounds the individual. Any change in the cell environment causes imbalance in cell homeostasis and f,ntction. Pollution is a significant cause of imbalance caused iii the inacYcenvironment. Interaction with polluted environments can have an adverse impact on the health of humans. The alarming rise in enviromilmieil cont.iniin :rtion has been linked to rises in levels of pesticides, ndltstr al effluents, domestic Waste, car exhausts and other anthropogenic activities. Persistent exposures to contaminant cause a negative imp,-, on brain health and development . Pollution also causes a change in the neurotransmitters and their receptor function leading to earl.;' recurrence of neurodcge,terative disorders such as flypoxia , Alzbeimers's and Huntington 's disease early in life.

Catalysis by Transition Metal Modified Ceria and Ceria-Zirconia Mixed Oxides Prepared via Sol-Gel Route

The aim of catalysis research is to apply the catalyst successfully in economically important reactions in an environmentally friendly way. The present work focuses on the modification of structural and surface properties of ceria and ceria-zirconia catalysts by the incorporation of transition metals. The applications of these catalysts in industrially important reactions like ethylbenzene oxidation, alkylation of aromatics are also investigated.Sol-gel method is effective for the preparation of transition metal modified ceria and ceria-zirconia mixed oxide since it produces catalyst with highly dispersed incorporated metal. Unlike that of impregnation method plugging of pores is not prominent for sol-gel derived catalyst materials. This prevents loss of surface area on metal modification as evident for BET surface area measurements.The powder X-ray diffraction analysis confirms the cubic structure of transition metal modified ceria and ceria-zirconia catalysts. The thermal stability is evident from TGA/DTA analysis. DR UV-vis spectra provide information on the coordination environment of the incorporated metal. EPR analysis ofCr, Mn and Cu modified ceria and a ceria-zirconia catalyst reveals the presence of different oxidation states of incorporated metal.Temperature programmed desorption of ammonia and thermogravimetric desorption of 2,6-dimethyl pyridine confirms the enhancement of acidity on metal incorporation. High a-methyl styrene selectivity in cumene cracking reaction implies the presence of comparatively more number of Lewis acid sites with some amount of Bronsted acid sites. The formation of cyclohexanone during cyclohexanol decomposition confirms the presence of basic sites on the catalyst surface.Mn and Cr modified catalysts show better activity towards ethylbenzene oxidation. A redox mechanism through oxometal pathway is suggested.All the catalysts were found to be active towards benzylation of toluene and a-xylene. The selectivity towards monoalkylated products remains almost 100%. The catalytic activity is correlated with the Lewis acidity of the prepared systems.The activity of the catalysts towards methylation of phenols depends on the strength acid sites as well as the redox properties of the catalysts. A strong dependence of methylation activity on the total acidity is illustrated.

Análisis de la incidencia de las campañas militares operación recompensa justa y operación plomo fundido en la redefinición de la doctrina de seguridad nacional de Israel

El propósito de esta investigación es determinar la incidencia de las campañas militares Operación Recompensa Justa y Operación Plomo Fundido en la redefinición de la Doctrina de Seguridad Nacional de Israel. El análisis se enfoca en una comparación entre la estrategia de 1973 -que hasta el momento había sido el pilar de Israel para conducirse en guerras regulares- y el documento de 2010, replanteado luego de que la Fuerzas de Defensa Israelís se enfrentaron a Hezbollah, en el sur del Líbano y a Hamas en la Franja de Gaza, para 2006 y 2009, respectivamente. La investigación es una monografía, pues utiliza la teoría del Realismo Defensivo en su dimensión explicativa, con el fin de dar cuenta de la cambiante percepción de seguridad frente a la existencia de amenazas no convencionales. Finalmente, a partir de la teoría de Relaciones Internacionales, es posible concluir que los Estados enfocan todas sus capacidades, entendidas en términos de poder material, hacia la consecución de sus objetivos estratégicos.

Reinventar un héroe: narrativas sobre los soldados rasos de la Guerra de Corea

Esta investigación se pregunta sobre las diferentes narrativas históricas que se han construido sobre la figura de los soldados rasos de la guerra de Corea, y por cómo ellos han generado estrategias en su relato que se ajustan a unos procesos históricos determinados.

La ambigüedad, las creencias y los estereotipos que rodean a lo que hoy en día se conoce como terrorismo: Una revisión de literatura

El terrorismo en la actualidad es considerado como uno de los conceptos más controversiales en los campos social, académico y político. El término se empieza a utilizar después de la Revolución Francesa, pero recientemente, a raíz de los atentados del 11 de septiembre de 2001, ha tomado suma relevancia y ha motivado numerosas investigaciones para tratar de entender qué es terrorismo. Aunque a la fecha existen varias revisiones sistemáticas, este trabajo tiene como propósito revisar, agrupar y concretar diferentes teorías y conceptos formulados por los autores que han trabajado sobre el concepto de “terrorismo” con el fin de entender las implicaciones de su utilización en el discurso, y cómo esto afecta la dinámica interna de las sociedades en relación con la violencia, las creencias, los estereotipos entre otros elementos. Para lograrlo, se revisaron 56 artículos, publicados entre los años 1985 y 2013; 10 fuentes secundarias entre noticias y artículos de periódicos correspondientes a los años 1995-2013 y 10 estudios estadísticos cuyos resultados nos aportan a la comprensión del tema en cuestión. La búsqueda se limitó al desarrollo histórico del terrorismo, sus diferentes dimensiones y el concepto social de la realidad de terrorismo. Los hallazgos demuestran que la palabra “terrorismo” constituye un concepto que como tal es un vehículo lingüístico que puede ser utilizado con fines, estratégicos movilizando al público conforme a través del discurso e intereses políticos, destacando la necesidad de estudiar las implicaciones psicológicas y sociales de su uso.