Bead, Hoop, and Spring as a Classical Spontaneous Symmetry Breaking Problem

We describe a simple mechanical system that involves Spontaneous Symmetry Breaking. The system consists of two beads constrained to slide along a hoop and attached each other through a spring. When the hoop rotates about a fixed axis, the spring-beads system will change its equilibrium position as a function of the angular velocity. The system shows two different regions of symmetry separated by a critical point analogous to a second order transition. The competitive balance between the rotational diynamics and the interaction of the spring causes an Spontaneous Symmetry Breaking just as the balance between temperature and the spin interaction causes a transition in a ferromagnetic system. In addition, the gravitational potential act as an external force that causes explicit symmetry breaking and a feature of first-order transition. Near the transition point, the system exhibits a universal critical behavior where the changes of the parameter of order is described by the critical exponent beta =1/2 and the susceptibility by gamma =1. We also found a chaotic behavior near the critical point. Through a demostrative device we perform some qualitative observations that describe important features of the system.Comment: 7 pages, 2 tables, 30 figures, LaTeX2

Sobre la distribución de Riella Helicophylla (Bory et Mont.) Mont en la Península Ibérica

Nueva localidad española de Riella helicophylla (Bory et Mont.) Mont. y mapa de distribución de la especie en la Peninsula Ibérica.A new record of Riella helicophylla from Spain and distributional map in the Iberian Peninsul

Electron beam induced electronic transport in alkyl amine-intercalated VOx nanotubes

The electron beam induced electronic transport in primary alkyl amine-intercalated V2O5 nanotubes is investigated where the organic amine molecules are employed as molecular conductive wires to an aminosilanized substrate surface and contacted to Au interdigitated electrode contacts. The results demonstrate that the high conductivity of the nanotubes is related to the non-resonant tunnelling through the amine molecules and a reduced polaron hopping conduction through the vanadium oxide itself. Both nanotube networks and individual nanotubes exhibit similarly high conductivities where the minority carrier transport is bias dependent and nanotube diameter invariant

Electron beam induced electronic transport in alkyl amine-intercalated VOx nanotubes

The electron beam induced electronic transport in primary alkyl amine-intercalated V2O5 nanotubes is investigated where the organic amine molecules are employed as molecular conductive wires to an aminosilanized substrate surface and contacted to Au interdigitated electrode contacts. The results demonstrate that the high conductivity of the nanotubes is related to the non-resonant tunnelling through the amine molecules and a reduced polaron hopping conduction through the vanadium oxide itself. Both nanotube networks and individual nanotubes exhibit similarly high conductivities where the minority carrier transport is bias dependent and nanotube diameter invariant

Respuesta inmune en bovinos a proteínas estructurales del virus de la rinotraqueitis infecciosa bovina (RIB)

Se realizó el seguimiento de las poblaciones de leucocitos mononucleares circulantes en bovinos, obtenidas mediante gradiente de densidad y se evaluó su respuesta al estímulo ocasionado por la inoculación de una vacuna a virus vivo modificado y de un antígeno de subunidades protéicas de membrana del virus de la RIB. Los marcadores celulares seleccionados fueron los de inmunoglobulinas de superficie (Igs) para linfocitos B, formación de rosetas E para linfocitos T y la capacidad fagocítica para monocitos. 3 grupos de bovinos denominados grupo 1, grupo 2 y control fueron sangrados durante 18 días para el establecimiento de los niveles celulares básicos. Posteriormente los animales del grupo 1 fueron vacunados vía intranasal con vacuna viva y los animales del grupo 2 con antígeno de subunidades protéicas en adyuvante por vía intramuscular. A continuación se siguió la evaluación celular durante un mes, período al cabo del cual los animales fueron desafiados vía intranasal con virus vivo virulento y evaluados durante 20 días, para un total de 67 muestreos. Se encontró que la vacunación con el antígeno de subunidades indujo elevación en la concentración linfoide Y y en la capacidad fagocítica, mayor conversión serológica y manifestaciones clínicas menos severas después de la vacunación y el desafío, así como neutralización del virus a nivel local. Lo anterior, unido a la eliminación del riesgo de diseminación e inducción de latencia viral demostró la mejor calidad del estímulo, sobre la vacuna de virus vivo. Se considera importante profundizar en el estudio de marcadores celulares más específicos y el seguimiento de las actividades citotóxica y blastogénica para la evaluación integral de la capacidad protectora de estos sistemas de vacunación.Cellular aspects of immune response to infectious bovine rhinotracheitis (IBR) virus infection were evaluated through the quantitation of mononuclear cell population from bovine peripheral blood, isolated by density gradient method. The cellular differential markers used were, surface immunoglobulin (Igs) for B-lymphocytes, the formation of "E" rosettes for T-lymphocytes and phagocytic activity for monocytes. Eleven animals distributed in three groups named, control, group 1 and group 2, were monitored one day apart during 18 days, in order to stablish basic cellular levels. Afterwards, groups 1 and 2 were vaccinated intranasally with viral purified membrane antigen respectivelly, and the same parameters evaluated during a month; subsequently, the groups were challenged with live virulent IBR virus and evaluated for an extra 20 days period, up to a total of 67 samplings. Following vaccination and challenge, group 2 showed high T-lymphocytes and phagocytic activity values, as well as severe clinical signs suggesting that the purified antigen stimulus was better than that produced with the live vaccine. Higher antibody titers and serological conversion in animals from this group as well as reduced risk of virus disemination and latency confirmed the former conclusion. Complementary, experiments for the evaluation of the protective capacity of this vaccination approach are considered of special importance.Ganado de doble propósito-Ganaderia doble proposit

Sobre la distribución de Riella helicophylla (Bory et Mont.) Mont. en la Península Ibérica

A new record of Riella helicophylla from Spain and distributional map in the Iberian Peninsula.Nueva localidad espafiola de Riella helicophylla (Boryet Mont.) Mont. y mapa de distribución de la especie en la Península Ibérica

Economic burden of air pollution in Colombia

To estimate indirect costs related to the loss of productivity due to premature mortality associated with air quality risk factors in Colombia, 2016. We estimated potential productivity years of life lost (PPYLL) related to indoor (biomass fuels) and outdoor pollution (PM2.5 and ozone). We analyzed deaths records of the Departamento Administrativo Nacional de Estadística, 2016, with the following basic causes of death related to air quality risk factors: isquemic hearth disease (IHD), cardiovascular disease (CD), lower respiratory tract infections (LRTI), lung cancer (LC) and chronic obstructive pulmonary disease(COPD), according to ICD-10. PPYLL were valued considering the productive age in Colombia, which ranges from 18-57 years for women and up to 62 for men. Three scenarios were built: lower loss (minimum legal wage), average loss [one per capita gross domestic product (GDPpc)] and higher loss (three GDPpc). PPYLL for the mentioned causes were multiplied by the fraction attributable to each air risk factor. The latest were estimated from IDEAM (outdoor) and the survey of Quality of Life 2016 and systematic reviews (indoor pollution). Costs were reported in American dollars, using the December 31 (2016) exchange rate: 1USD=3,000.7 Colombian Pesos. The economic burden due to premature deaths caused by the analyzed diseases was US$845,967,999 ($444,320,058-$2,537,903,997). From this burden, 17.8$150,585,143 ($79,090,461-451,755,428). Regarding to the studied diseases, IHD deaths caused by air quality risk factors accounted US$83.007.582. The second with the highest economic burden attributable to air quality risk factors was CD (US$32,750,315), followed by LRTI (US$22,077,091), LC (US$6,909,659) and COPD (US$5,840,495). The exposure to PM2.5 particulate matter represented the largest share of the economic burden attributable to air quality risk factors. Our estimations suggest that premature deaths caused by exposure to air qualityrisk factors represented 0.052% of GDP for 2016