Non-critically squeezed light via spontaneous rotational symmetry breaking

We theoretically address squeezed light generation through the spontaneous breaking of the rotational invariance occuring in a type I degenerate optical parametric oscillator (DOPO) pumped above threshold. We show that a DOPO with spherical mirrors, in which the signal and idler fields correspond to first order Laguerre-Gauss modes, produces a perfectly squeezed vacuum with the shape of a Hermite-Gauss mode, within the linearized theory. This occurs at any pumping level above threshold, hence the phenomenon is non-critical. Imperfections of the rotational symmetry, due e.g. to cavity anisotropy, are shown to have a small impact, hence the result is not singular.Comment: 4 pages, 1 figure, replaced with resubmitted versio

Spontaneous symmetry breaking as a resource for noncritically squeezed light

In the last years we have proposed the use of the mechanism of spontaneous symmetry breaking with the purpose of generating perfect quadrature squeezing. Here we review previous work dealing with spatial (translational and rotational) symmetries, both on optical parametric oscillators and four-wave mixing cavities, as well as present new results. We then extend the phenomenon to the polarization state of the signal field, hence introducing spontaneous polarization symmetry breaking. Finally we propose a Jaynes-Cummings model in which the phenomenon can be investigated at the single-photon-pair level in a non-dissipative case, with the purpose of understanding it from a most fundamental point of view.Comment: Review for the proceedings of SPIE Photonics Europe. 11 pages, 5 figures

Back to Nature: Native Flora for Wildlife and People. The Lincoln University Native Plants Program

Presentation made at Latinos in the Heartland (12th : 2014 : St. Louis, Mo.) and published in the annual conference proceedingThe overall objective of the Lincoln University Cooperative Extension (LUCE) Sprouts and Roots Program (SRP) is to improve the well-being of minorities and other underserved communities through gardening and to promote intergenerational activities in Jefferson City and elsewhere in Missouri. To meet this objective, training is offered on nutrition, wellness, and gardening. The effects of gardening and healthy habits on the physical and psychological health of seniors and youth are being evaluated in an ongoing research study. Recruitment was done in schools, senior centers, Boys and Girls clubs, churches, and other locations with the assistance of the LUCE Paula Carter Center on Minority Health and Aging. Flyers, emails, calls, and personal visits were used to contact potential participants. Children and seniors attended indoor and outdoor classes in spring and fall, and pretests and posttests were provided to determine their change in knowledge of particular topics. Participants practiced their new knowledge to grow their own food at the community garden located on campus. Sixteen adult seniors and 16 children participated in 2012. The farmers market, also located on campus and adjacent to the garden, is offering the opportunity to SRP participants and area farmers to sell produce, baked goods, and other value-added products. An average of 14 vendors, and a total of 43, attended the market in 2012 where fresh or value-added products were sold on Thursdays and Saturdays during the growing season. Some vendors continued selling their products during the winter months. More than 4,000 people of different ethnicities, ages, and genders attended the market on Saturdays in 2012, compared to 1,305 in 2011. The SRP is providing communities the opportunity to develop their own value-added products by facilitating their access to a commercial kitchen recently opened to the public, located next to the market and community garden

Estructura de tallas y composición sexual de Eurypodius Latreillii Guérin, 1828 (Brachyura) y Pagurus Comptus White, 1847 (Anomura) en el extremo sur de Chile

The decapod crustaceans Eurypodius latreillii (Brachyura) and Pagurus comptus (Paguridae) were the most frequently occurring species in Agassiz trawl (AGT) samples obtained during the Chilean - German - Italian Victor Hensen Expedition in the Straits of Magellan and south of the Beagle Channel. Sex composition and length structure aspects were studied using the material from 15 stations in the two areas, which comprised 773 specimens of E. latreillii and 647 P. comptus. The size frequency of both species was characterized by the presence of small individuals in shallow waters. The sex composition varied with depth, indicating a dominance of E. latreillii females in deep waters, whereas no such pattern was observed in P. comptus. These differences may be caused by epizoites of E. latreillii and the availability of vacant gastropod shells for P. comptus, in addition to geographical aspects and life-cycle patterns of these speciesLos crustáceos decápodos Eurypodius latreillii (Brachyura) y Pagurus comptus (Anomura), fueron las especies encontradas con mayor frecuencia en las muestras obtenidas durante la Expedición Chilena - Alemana - Italiana “Victor Hensen” (Octubre/Noviembre de 1994) en el Estrecho de Magallanes y al sur del Canal del Beagle, en el extremo sur de Chile. En estas localidades se obtuvieron las muestras mediante una red de tipo Agassiz. Los ejemplares fueron medidos, pesados y sexados, posteriormente se analizó la composición sexual y la estructura de tallas de estas especies. Se recolectaron un total de 773 individuos de E. latreillii y 647 individuos de P. comptus. Este material corresponde a los especímenes capturados en 15 estaciones. La estructura de tallas para ambas especies se caracterizó por la presencia de ejemplares de menor tamaño hacia zonas someras. La composición sexual presentó variaciones respecto de la profundidad, indicando una dominancia de hembras en aguas profundas para E. latreillii, pero este patrón no se observó en P. comptus. Los patrones observados dependerían de la presencia de epibiontes sobre el caparazón de E. latreillii y la disponibilidad de conchas vacías de gastrópodos para P. comptus, además de aspectos geográficos y de los ciclos de vida que presentarían ambas especies en la región

Protesta contra las corridas de toros

Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 201

Convección natural asociada a pozas de enfriamiento por aspersión

Las pozas de enfriamiento por aspersión son intercambiadores de calor de tipo evaporativo de contacto directo agua-aire. Así, agua de proceso a alta temperatura se enfrla mediante la aspersión en pequeñas gotas, consiguiendo un aumento considerable del área de transferencia de calor y masa, resultando en una mayor cantidad de energía que las gotas entregan al aire debido al efecto convectivo y al calor latente de vaporización de la masa de agua que se evapora. Las transferencias que se producen alteran la temperatura y humedad del aire circundante, dando origen a fuerzas de empuje que inducen a una convección natural de aire en la poza de aspersión. En otro trabajo de los autores (10) se estudia este efecto, considerando que la convección natural inducida es conocida, con ello se consigue una considerable simplificación del problema planteado. En el presente trabajo no se considera esta simplificación, y el estudio se realiza acoplando numéricamente las ecuaciones de continuidad, transporte de momemtum y la ecuación de Poisson, para el campo dinámico y las ecuaciones de transporte de energfa y transporte de masa para los campos térmico y másico. Ambos campos están ligados principalmente a través de la fuerza de empuje del aire caliente y hlímedo que atraviesa la zona de aspersión, como también de las propiedades del aire. Se presenta el estudio, modelación y resolución numérica de tipo discreta de una poza cilíndrica, atendiendo las ventajas que este tipo de coordenadas presenta para el modelo. El sistema de ecuaciones álgebra diferencia/no lineal resultante, se resuelve por el método numérico de diferencias finitas

Epifisiolisis de la extremidad superior del fémur en un adulto asociada a craneofaringioma

Se presenta un caso de epifisiolisis de la extremidad superior del fémur en un paciente de 22 años, asociado a un hipopituitarismo de origen tumoral (Craneofaringioma). Se estudia la asociación entre epifisiolisis de la extremidad superior del fémur y transtornos endocrinos.We report an adult male, 22 years old, with slipping of the uppe r femoral epiphysis, afected by hypopituitarism due to intracranial tumour (Craniopharingyoma). The clinical assocition betwee n slipped uppe r femoral epiphysis and endocrine disease is studied

Cross-cultural and experiential learning in El Salvador for extension specialists : lessons learned in the field

A delegation from Lincoln University (LU) Cooperative Extension of Missouri participated in a 12-day exchange program that included visits to communities and institutions in Central and Western El Salvador. The delegation included LU Native Plants Program (LU-NPP) staff and members of four communities in Missouri. The objectives were: 1. For the LU delegation to be immersed in the Salvadoran culture and learn how communities protect their resources and use native plants in their daily lives; 2. To exchange lessons learned between the LU-NPP, Salvadoran educators, producers, farmers, and communities; and 3. Identify organizations or agencies interested in forming alliances with the LU-NPP. Joint collaborative efforts between LU and organizations in El Salvador will help empower small farmers and will further advance agricultural and ecological education for low-income students in El Salvador and in Missouri. During site visits, local leaders from different agencies and community organizations and the LU delegation engaged in conversations to learn from each other's experiences. Salvadoran specialists were surprised to learn that Lincoln University also works with low-income communities and that farms in Missouri do not only grow cash crops. Many of the Native Plant Program's lessons learned in Missouri could be adopted in El Salvador to help small farmers and rural entrepreneurs. Evaluations from participants of this exchange program indicate that the delegation members increased their level of understanding of Latino culture and some had the opportunity to practice their Spanish skills which they can also use in Missouri. This program was funded by the USDA National Institute of Food and Agriculture (NIFA) and was part of two Capacity Building Grants