An easy to control all-metal in-line-series ohmic RF MEMS switch

Copyright @ 2010 Springer-VerlagThe analysis, design and simulation of a novel easy to control all-metal in-line-series ohmic RF MEMS switch is presented, for applications where the operating frequency ranges from DC to 4 GHz. The proposed switch, due to its unique shape and size, assures high isolation and great linearity fulfilling the necessary requirements as concerns loss, power handling and power consumption. Simplicity has been set as the key success factor implying robustness and high fabrication yield. On the other hand, the specially designed cantilever-shape (hammerhead) allows distributed actuation force ensuring high controllability as well as reliability making the presented RF MEMS switch one of its kind

Weak charge form factor and radius of 208Pb through parity violation in electron scattering

We use distorted wave electron scattering calculations to extract the weak charge form factor F_W(q), the weak charge radius R_W, and the point neutron radius R_n, of 208Pb from the PREX parity violating asymmetry measurement. The form factor is the Fourier transform of the weak charge density at the average momentum transfer q=0.475 fm$^{-1}$. We find F_W(q) =0.204 \pm 0.028 (exp) \pm 0.001 (model). We use the Helm model to infer the weak radius from F_W(q). We find R_W= 5.826 \pm 0.181 (exp) \pm 0.027 (model) fm. Here the exp error includes PREX statistical and systematic errors, while the model error describes the uncertainty in R_W from uncertainties in the surface thickness \sigma of the weak charge density. The weak radius is larger than the charge radius, implying a "weak charge skin" where the surface region is relatively enriched in weak charges compared to (electromagnetic) charges. We extract the point neutron radius R_n=5.751 \pm 0.175 (exp) \pm 0.026 (model) \pm 0.005 (strange) fm$, from R_W. Here there is only a very small error (strange) from possible strange quark contributions. We find R_n to be slightly smaller than R_W because of the nucleon's size. Finally, we find a neutron skin thickness of R_n-R_p=0.302\pm 0.175 (exp) \pm 0.026 (model) \pm 0.005 (strange) fm, where R_p is the point proton radius.Comment: 5 pages, 1 figure, published in Phys Rev. C. Only one change in this version: we have added one author, also to metadat

Technical note: A simple theoretical model framework to describe plant stomatal “sluggishness” in response to elevated ozone concentrations

Elevated levels of tropospheric ozone, O3, cause damage to terrestrial vegetation, affecting leaf stomatal functioning and reducing photosynthesis. Climatic impacts under future raised atmospheric greenhouse gas (GHG) concentrations will also impact on the net primary productivity (NPP) of vegetation, which might for instance alter viability of some crops. Together, ozone damage and climate change may adjust the current ability of terrestrial vegetation to offset a significant fraction of carbon dioxide (CO2) emissions. Climate impacts on the land surface are well studied, but arguably large-scale modelling of raised surface level O3 effects is less advanced. To date most models representing ozone damage use either O3 concentration or, more recently, flux-uptake-related reduction of stomatal opening, estimating suppressed land–atmosphere water and CO2 fluxes. However there is evidence that, for some species, O3 damage can also cause an inertial “sluggishness” of stomatal response to changing surface meteorological conditions. In some circumstances (e.g. droughts), this loss of stomata control can cause them to be more open than without ozone interference. To both aid model development and provide empiricists with a system on to which measurements can be mapped, we present a parameter-sparse framework specifically designed to capture sluggishness. This contains a single time-delay parameter τO3, characterizing the timescale for stomata to catch up with the level of opening they would have without damage. The larger the value of this parameter, the more sluggish the modelled stomatal response. Through variation of τO3, we find it is possible to have qualitatively similar responses to factorial experiments with and without raised O3, when comparing to reported measurement time series presented in the literature. This low-parameter approach lends itself to the inclusion of ozone-induced inertial effects being incorporated in the terrestrial vegetation component of Earth system models (ESMs)

Caspase 3 blocking avoids the expression of autoantigens triggered by apoptosis in neonatal Balb/c mice skin

Apoptosis is a physiologic process that maintains the cellular exchange; normally the cellular remains are cleared by phagocytosis without infl ammation. In autoimmunity defects in apoptosis may occur, which play an important role in pathogenesis. During the lymphoid ontogeny the failure of the Fas pathway could decrease the negative selection process and such defect could allow the survival of autoimmune lymphocyte clones resulting in a central tolerance breaking down; in other instances the peripheral tolerance is disrupted by an insuffi cient clearance of apoptotic material, which is a potential risk for activating the pre-existent auto-reactive clones

Calibration and validation of an algorithm for remote sensing of turbidity over La Plata river estuary, Argentina

The La Plata River, located at 35°S on the Atlantic coast, is one of the largest waterways of South America. It carries a large amount of suspended particulate and dissolved organic matter, and is considered among the most turbid waters of the world. Very high values of total suspended matter have been reported in this region, with mean values ranging from 100 to 300 g m-3 and extreme concentrations up to 400 g m-3. Satellite sensors have shown to be the best tools available to map river plumes and to study their influence on the adjacent ocean. However, global algorithms for remotely estimating sediment concentration are not currently available. Moreover, such high sediment loads represent a challenge to atmospheric correction algorithms which usually rely on the assumption of zero water-leaving reflectance in the near infrared or short wave infrared part of the spectrum (black pixel assumption). In the extremely turbid waters of La Plata Estuary such assumptions are not valid. A two band algorithm to estimate turbidity using near infrared and the short wave infrared bands (858 nm and 1240 nm) of the MODIS-Aqua sensor is presented. The model is calibrated using in situ reflectance and turbidity measurements from turbid waters of the Southern North Sea and Scheldt River (Belgium) and then applied to MODIS imagery of La Plata River estuary (Argentina). A good correlation was found between modelled and in situ turbidity values when the algorithm was applied to concurrent MODIS imagery. Moreover, satellite-derived turbidity maps show a spatial distribution of sediment consistent with patterns and characteristic features of the estuary

Efectividad del agua electrolizada oxidadora (EO) en la inactivación de Listeria monocytogenes en lechuga ( Lactuca sativa L.)

Se evaluó la efectividad del agua electrolizada oxidadora (EO) en la inactivación de Listeria monocytogenes en lechuga; para ello se construyó una celda electrolítica para la producción de agua EO a partir de una solución de NaCl al 5%, con una concentración de cloro residual de 29 partes por millón (ppm) y pH 2.83. Cinco de las 10 cepas de Listeria monocytogenes mas resistentes a la acción del hipoclorito de sodio , fueron obtenidas a partir de muestras de pollo procesado e inoculadas en 9 ml de agua EO o 9 ml de agua desionizada estéril (control) e incubadas a 15°C durante 5, 10, 15 y 20 minutos. La población se determinó por recuento en placa en agar Columbia, obteniéndose una reducción de 6.6 UL a los 5 minutos de exposición. Las cepas seleccionadas fueron utilizadas como suspensión mixta (9.56 UL, 10 9 UFC/ml) para inocular 35 lechugas por el método de inmersión. Se sumergieron 6.25 g de cada lechuga en 375 ml de agua EO o agua destilada (control) a 15 °C durante 5 minutos. La población promedio de Listeria monocytogenes después del tratamiento con agua EO y con agua destilada, se redujo en 3.92 y 2.46 UL respectivamente. Se demostró que el agua EO tiene un efecto bactericida estadísticamente significativo (p=0.00001). Para mejorar el efecto del agua EO sobre L. monocytogenes en lechuga, se evaluó su efectividad en combinación con ácido acético al 6% (vinagre). Reducción de la población en 5.49 UL demuestran que hay un efecto sinergista de ambos agentes antimicrobianos sobre la viabilidad de las células de L. monocytogenes