Coronal Loop Expansion Properties Explained Using Separators

One puzzling observed property of coronal loops is that they are of roughly constant thickness along their length. Various studies have found no consistent pattern of width variation along the length of loops observed by TRACE and SOHO. This is at odds with expectations of magnetic flux tube expansion properties, which suggests that loops are widest at their tops, and significantly narrower at their footpoints. Coronal loops correspond to areas of the solar corona which have been preferentially heated by some process, so this observed property might be connected to the mechanisms that heat the corona. One means of energy deposition is magnetic reconnection, which occurs along field lines called separators. These field lines begin and end on magnetic null points, and loops forming near them can therefore be relatively wide at their bases. Thus, coronal energization by magnetic reconnection may replicate the puzzling expansion properties observed in coronal loops. We present results of a Monte Carlo survey of separator field line expansion properties, comparing them to the observed properties of coronal loops.Comment: 16 pages, 9 figures, to be submitted to Ap

DE LA PLANEACIÓN NORMATIVA A LA PARTICIPATIVA EN COLOMBIA: EL CASO DEL MANEJO DE LOS RECURSOS AMBIENTALES

The article makes a synthesis of the process of planning in Colombia. In this work it is emphasized that the first techniques of planning were introduced by the CEPAL (Economic Commission for Latin America), and as much the process that lived the country in the Eighties as the growth of the Colombian cities affected the process of urban planning. In the work one needs as you consolidate the participation in the proposals of planning at the different levels and a reflection is made surroundings to the participative planning in the handling of the environmental resources.El artículo hace una síntesis del proceso de planeación en Colombia. Por consiguiente, se van a puntualizar, por una parte, las primeras técnicas de planeación introducidas por la Comisión Económica para América Latina (CEPAL) y, por otra cómo el proceso descentralizado, que vivió el país en la década del ochenta, y el crecimiento de las ciudades colombianas incidieron en el proceso de planeación urbana. Por último, se va a precisar cómo se consolida la participación en las propuestas de la planeación en los diferentes niveles y se hace una reflexión entorno a la planeación participativa en el manejo de los recursos ambientale

Protective Effect of Melatonin Against Mitomycin C-Induced Genotoxic Damage in Peripheral Blood of Rats

Mitomycin C (MMC) generates free radicals when metabolized. We investigated the effect of melatonin against MMC-induced genotoxicity in polychromatic erythrocytes and MMC-induced lipid peroxidation in brain and liver homogenates. Rats (N = 36) were classified into 4 groups: control, melatonin, MMC, and MMC + melatonin. Melatonin and MMC doses of 10 mg/kg and 2 mg/kg, respectively, were injected intraperitoneally. Peripheral blood samples were collected at 0, 24, 48, 72, and 96 hours posttreatment and homogenates were obtained at 96 hours posttreatment. The number of micronucleated polychromatic erythrocytes (MN-PCE) per 1000 PCE was used as a genotoxic marker. Malondialdehyde (MDA) plus 4-hydroxyalkenal (4-HDA) levels were used as an index of lipid peroxidation. The MMC group showed a significant increase in MN-PCE at 24, 48, 72, and 96 hours that was significantly reduced with melatonin begin coadministrated. No significant differences were found in lipid peroxidation. Our results indicate that MMC-induced genotoxicity can be reduced by melatonin

Thermal and phase transformations analysis in a PREMOMET® steel

Thermal analysis in a PREMOMET® steel has been performed by differential scanning calorimetry (DSC) and highresolution dilatometry. The phase transformation temperatures (Ac1, Ac3, Ms and Mf) of this steel were obtained by the two methods at different heating rates showing good agreement between both techniques. The enthalpy of α-γ transformation for this steel was measured using the thermograms acquired by DSC and microstructure was analyzed by scanning electron microscope (SEM). The results showed that this steel retained a martensitic structure for all conditions

Thermal and phase transformations analysis in a PREMOMET® steel

Thermal analysis in a PREMOMET® steel has been performed by differential scanning calorimetry (DSC) and highresolution dilatometry. The phase transformation temperatures (Ac1, Ac3, Ms and Mf) of this steel were obtained by the two methods at different heating rates showing good agreement between both techniques. The enthalpy of α-γ transformation for this steel was measured using the thermograms acquired by DSC and microstructure was analyzed by scanning electron microscope (SEM). The results showed that this steel retained a martensitic structure for all conditions

Optical calibration facility at the Izaña Atmospheric Research Center [Póster]

Póster presentado en: 37th Annual European Meeting on Atmospheric Studies by Optical Methods, celebrado en 2010 en Valladolid.Financial supports from the Spanish MICIIN (ref.CGL2008-05939-CO3-00/CLIandCGL2009-09740) and from the GR-220 Project of the Junta de Castilla y León are gratefully acknowledged

Estrés parental y desarrollo infantil en niños prematuros

El presente trabajo trata de analizar si los niveles de estrés experimentados por los progenitores inciden sobre el desarrollo mental y motor de un grupo de niños nacidos demasiado pequeños o demasiado pronto. Participaron 19 niños y niñas nacidos, con menos de 36 semanas de gestación (media 29,84) y menos de 1500 gramos (media 1099,89), en el Hospital 12 de octubre de Madrid cuyos padres y madres consintieron participar en este trabajo. Los instrumentos utilizados fueron la Escala BSID-II para obtener los índices del desarrollo mental y psicomotor en los niños cuando alcanzaron la edad 2 años y la PSI de Abidin, para valorar el estrés total de los padres y madres participantes, así como su percepción de Malestar Paterno, Interacción Disfuncional y Niño Difícil. Los datos fueron sometidos a análisis de comparaciones de medias para muestras independientes. Los resultados indican que existen diferencias significativas entre los altos y los bajos niveles de estrés en cuanto a su incidencia en el desarrollo. En general, tanto en las madres como en los padres, cuando se obtiene una puntuación baja de estrés, existe un mejor desarrollo mental y psicomotor en los niños. Estos resultados se discuten a la luz de las investigaciones sobre el tema y se analizan las implicaciones para la elaboración de programas de atención temprana.The current document analyze if the parent’s stress levels influence the mental and motor development of a children’s group being born too young or too small. The participants were 19 preterm children born at the “Hospital 12 de Octubre” of Madrid with less than 36 gestation weeks (mean 29,84) and 1500 grammes (mean 1099,89), whose parents were agree to take part in this study. The employed instruments were the Bayley Scales of Infant Development (BSID-II) to obtain the mental and psychomotor index scores of the toddlers at 2 years old; and the Parenting Stress Index Short Form (PSI) of Abidin. to assess the Total Stress of the parents, and their perception of Parental Distress, Dysfunctional Parent-Child Interactions and Difficult Child also. The obtained data were analyzed comparing the means of two independent samples. The results show that there are significant differences in the children’s development depending of the high or low parental stress levels. In general terms, when parents have low levels of stress, a better mental and psychomotor development is observed in their children. These results are discussed in the light of other researches about the issue, being considered as well, their implications for the implementation of early intervention programs.peerReviewe

Soil Aggregation and Soil Organic Carbon Stabilization: Effects of Management in Semiarid Mediterranean Agroecosystems

In semiarid agroecosystems of the Ebro valley (NE Spain) soils are characterized by low soil organic matter (SOM) and a weak structure. In this study we investigated the individual and combined effect of tillage system (no-tillage, NT; reduced tillage, RT; conventional tillage, CT) and cropping system (barley–fallow rotation at the Peñaflor site, PN-BF and continuous barley at the Peñaflor site, PN-BB) on soil organic carbon (SOC) storage as well as the physical protection of SOM fractions by soil aggregates in three long-term experimental sites. In both cropping systems, total SOC content was more than 30% higher in NT compared with CT in the 0- to 5-cm depth. The suppression of fallowing in the PN-BB cropping system led to a greater SOC stabilization only in NT. In all the three sites, greater proportion of water-stable macroaggregates (>250 µm) was found under NT than under CT in the 0- to 5-cm depth. Macroaggregate organic C concentration (250–2000 µm) was greater in NT compared with CT in the BB cropping system, but did not differ with tillage treatment in the PN-BF rotation. Greater proportion of microaggregates within macroaggregates in NT compared with CT was only found in the Agramunt site (AG). However, greater C stabilized inside these microaggregates was observed in AG, Selvanera site (SV), and PN-BB in the 0- to 5-cm depth. The results of this study demonstrate that in the semiarid Mediterranean agroecosystems of the Ebro valley, the adoption of NT together with the suppression of long-fallowing period can significantly increase the amount of SOC stabilized in the soil surface and improve soil structure and aggregation.This research was supported by the Comisión Interministerial de Ciencia y Tecnología of Spain (Grants AGL2001-2238-CO2-01, AGL 2004-07763-C02-02 and AGL2007-66320-CO2-02/AGR) and the European Union (FEDER funds).Peer reviewe

Evidence of Impulsive Heating in Active Region Core Loops

Using a full spectral scan of an active region from the Extreme-Ultraviolet Imaging Spectrometer (EIS) we have obtained Emission Measure EM$(T)$ distributions in two different moss regions within the same active region. We have compared these with theoretical transition region EMs derived for three limiting cases, namely \textit{static equilibrium}, \textit{strong condensation} and \textit{strong evaporation} from \cite{ebtel}. The EM distributions in both the moss regions are strikingly similar and show a monotonically increasing trend from $\log T[\mathrm{K}]=5.15 -6.3$. Using photospheric abundances we obtain a consistent EM distribution for all ions. Comparing the observed and theoretical EM distributions, we find that the observed EM distribution is best explained by the \textit{strong condensation} case (EM$_{con}$), suggesting that a downward enthalpy flux plays an important and possibly dominant role in powering the transition region moss emission. The downflows could be due to unresolved coronal plasma that is cooling and draining after having been impulsively heated. This supports the idea that the hot loops (with temperatures of 3{-}5 MK) seen in the core of active regions are heated by nanoflares.Comment: 17 pages, 4 figures, Accepted for publication in The Astrophysical Journa