Assessment of catheter-manometer systems used for invasive blood pressure measurement

Direct measurement of blood pressure using a fluid-filled catheter and an electromechanical transducer is widely accepted in clinical practice. However, errors associated with the measurement are often not appreciated and these catheter-manometer systems are frequently unable to accurately reproduce applied pressures. To assess the accuracy of catheter-manometer systems used for invasive arterial blood pressure measurements, in vitro and in vivo evaluations were performed. The frequency response (described in terms of damped natural frequency and damping factor) for a variety of cannulae, pressure tubing and stopcocks (and combinations thereof) and their dependence on various parameters (catheter length, lumen diameter, fluid temperature and catheter material) were measured using an hydraulic pressure generator. The design and construction details of the pressure generator are presented. It was found that the damped natural frequency of the catheter-manometer system is directly proportional to lumen diameter of the pressure tubing/catheter. Furthermore, damping factor is inversely related to the damped natural frequency and stiffer catheter material (for identical radius ratios) results in higher damped natural frequency. Catheter length is inversely related to damped natural frequency and the resonant frequency decreases for an increase in fluid operating temperature. It was established that all catheter-manometer systems tested were under-damped (0.15 < β < 0.37) and that the damped natural frequency ranged from 10.5 Hz for 1500 mm to 27.0 Hz for pressure tubing of 300 mm in length. Furthermore, catheter-manometer systems which had pressure tubing in excess of 300 mm in length did not comply with the bandwidth requirements for accurate dynamic blood pressure measurement. For the in vivo assessment of the catheter-manometer system, the blood pressure waveform was analysed in the time and frequency domains. It was established that in 60 percent of the cases, the systolic pressure peak was higher when measured by a narrow bandwidth catheter-manometer system compared to that measured by a wide bandwidth system. Furthermore, values of dp/dt maximum were lower for wide bandwidth catheter-manometer systems than those measured by narrow bandwidth systems for heart rates above 90 beats per minute. In the frequency domain analysis, artifact was sometimes found to occur at frequencies higher than the bandwidth of the catheter-manometer system. This high frequency artifact was found to distort the blood pressure waveform and resulted in false high dp/dt and peak systolic pressures

Assessing the role of deep rooted vegetation in the climate system with model simulations: mechanism, comparison to observations and implications for Amazonian deforestation

Deep rooted vegetation (of up to 68 m) has been found in many parts of the tropics. However, models of the general atmospheric circulation (GCMs) typically use rooting depths of less than 2 m in their land surface parametrizations. How does the incorporation of deep roots into such a model affect the simulated climate? We assess this question by using a GCM and find that deeper roots lead to a pronounced seasonal response. During the dry season, evapotranspiration and the associated latent heat flux are considerably increased over large regions leading to a cooling of up to 8 K. The enhanced atmospheric moisture is transported towards the main convection areas in the inner tropical convergence zone where it supplies more energy to convection thus intensifying the tropical circulation patterns. Comparison to different kinds of data reveals that the simulation with deeper roots is much closer to observations. The inclusion of deep roots also leads to a general increased climatic sensitivity to rooting depth change. We investigate this aspect in the context of the climatic effects of large-scale deforestation in Amazonia. Most of the regional and remote changes can be attributed to the removal of deep roots. We conclude that deep rooted vegetation is an important part of the tropical climate system. Without the consideration of deep roots, the present-day surface climate cannot adequately be simulated

Global surface-ocean pCO2 and sea–air CO2 flux variability from an observation-driven ocean mixed-layer scheme

A temporally and spatially resolved estimate of the global surface-ocean CO₂ partial pressure field and the sea–air CO₂ flux is presented, obtained by fitting a simple data-driven diagnostic model of ocean mixed-layer biogeochemistry to surface-ocean CO₂ partial pressure data from the SOCAT v1.5 database. Results include seasonal, interannual, and short-term (daily) variations. In most regions, estimated seasonality is well constrained from the data, and compares well to the widely used monthly climatology by Takahashi et al. (2009). Comparison to independent data tentatively supports the slightly higher seasonal variations in our estimates in some areas. We also fitted the diagnostic model to atmospheric CO₂ data. The results of this are less robust, but in those areas where atmospheric signals are not strongly influenced by land flux variability, their seasonality is nevertheless consistent with the results based on surface-ocean data. From a comparison with an independent seasonal climatology of surface-ocean nutrient concentration, the diagnostic model is shown to capture relevant surface-ocean biogeochemical processes reasonably well. Estimated interannual variations will be presented and discussed in a companion paper

Measurements of greenhouse gases and related tracers at Bialystok tall tower station in Poland

Quasi-continuous, in-situ measurements of atmospheric CO2, O2/N2, CH4, CO, N2O, and SF6 have been performed since August 2005 at the tall tower station near Bialystok, in Eastern Poland, from five heights up to 300 m. Besides the in-situ measurements, flask samples are filled approximately weekly and measured at Max-Planck Institute for Biogeochemistry for the same species and, in addition, for H2, Ar/N2 and the stable isotopes 13C and 18O in CO2. The in-situ measurement system was built based on commercially available analysers: a LiCor 7000 for CO2, a Sable Systems "Oxzilla" FC-2 for O2, and an Agilent 6890 gas chromatograph for CH4, CO, N2O and SF6. The system was optimized to run continuously with very little maintenance and to fulfill the precision requirements of the CHIOTTO project. The O2/N2 measurements in particular required special attention in terms of technical setup and quality assurance. The evaluation of the performance after more than three years of operation gave overall satisfactory results, proving that this setup is suitable for long term remote operation with little maintenance. The precision achieved for all species is within or close to the project requirements. The comparison between the in-situ and flask sample results, used to verify the accuracy of the in-situ measurements, showed no significant difference for CO2, O2/N2, CH4 and N2O, and a very small difference for SF6. The same comparison however revealed a statistically significant difference for CO, of about 6.5 ppb, for which the cause could not be fully explained. From more than three years of data, the main features at Bialystok have been characterized in terms of variability, trends, and seasonal and diurnal variations. CO2 and O2/N2 show large short term variability, and large diurnal signals during the warm seasons, which attenuate with the increase of sampling height. The trends calculated from this dataset, over the period August 2005 to December 2008, are 2.02±0.46 ppm/year for CO2 and -23.2±2.5 per meg/year for O2/N2. CH4, CO and N2O show also higher variability at the lower sampling levels, which in the case of CO is strongly seasonal. Diurnal variations in CH4, CO and N2O mole fractions can be observed during the warm season, due to the periodicity of vertical mixing combined with the diurnal cycle of anthropogenic emissions. We calculated increase rates of 10.1±4.4 ppb/year for CH4, (-8.3)±5.3 ppb/year for CO and 0.67±0.08 ppb/year for N2O. SF6 shows only few events, and generally no vertical gradients, which suggests that there are no significant local sources. A weak SF6 seasonal cycle has been detected, which most probably is due to the seasonality of atmospheric circulation. SF6 increased during the time of our measurement at an average rate of 0.29±0.01 ppt/year

P 419 Comparison of tight junctions permeability and modulation in iris pigment epithelium and retinal pigment epithelium in vitro

Amb una superfície: 0,61 ha, de basalt i aigua nebulitzada.Barragán, Pedro (dissenyador)Gran pla general de El Volcà,conegut com la Carbonera. El carbó calent era mullat per aigua subterrània i desprenia vapor. Actualment està inactiu. Destaquen el pg. Josep Carner amb el monument a Colom i els edificis de Capitania i Duana

Sintering of BaCe(sub 0.85)Y(sub 0.15)O(sub 3-delta) with/without SrTiO3 Dopant

The perovskite composition, BaCe(sub 0.85)Y(sub 0.15)O(sub 3-delta), displays excellent protonic conduction at high temperatures making it a desirable candidate for hydrogen separation membranes. This paper reports on the sintering behavior of BaCe(sub 0.85)Y(sub 0.15)O(sub 3-delta) powders doped with SrTiO3. Two methods were used to synthesize BaCe(sub 0.85)Y(sub 0.15)O(sub 3-delta) powders: (1) solid state reaction and (2) wet chemical co-precipitation. Co-precipitated powder crystallized into the perovskite phase at 1000 C for 4 hrs. Complete reaction and crystallization of the perovskite phase by solid state was achieved by calcining at 1200 C for 24 hrs. Solid state synthesis produced a coarser powder with an average particle size of 1.3 microns and surface area of 0.74 sq m/g. Co-precipitation produced a finer powder with a average particle size of 65 nm and surface area of 14.9 sq m/g. Powders were doped with 1, 2, 5, and 10 mole % SrTiO3. Samples were sintered at 1450 C, 1550 C and 1650 C. SrTiO3 enhances sintering, optimal dopant level is different for powders synthesized by solid state and co-precipitation. Both powders exhibit similar grain growth behavior. Dopant levels of 5 and 10 mole % SrTiO3 significantly enhances the grain size

Influência do meio de cultura no estabelecimento e multiplicação in vitro de Eucalyptus sp.

Resumo

Identification. The missing link between joint attention and imitation

In this paper we outline our hypothesis that human intersubjective engagement entails identifying with other people. We tested a prediction derived from this hypothesis that concerned the relation between a component of joint attention and a specific form of imitation. The empirical investigation involved “blind” ratings of videotapes from a recent study in which we tested matched children with and without autism for their propensity to imitate the self-/other-orientated aspects of another person's actions. The results were in keeping with three a priori predictions, as follows: (a) children with autism contrasted with control participants in spending more time looking at the objects acted upon and less time looking at the tester; (b) participants with autism showed fewer “sharing” looks toward the tester, and although they also showed fewer “checking” and “orientating” looks, they were specifically less likely to show any sharing looks; and, critically, (c) within each group, individual differences in sharing looks (only) were associated with imitation of self–other orientation. We suggest that the propensity to adopt the bodily anchored psychological stance of another person is essential to certain forms of joint attention and imitation, and that a weak tendency to identify with others is pivotal for the developmental psychopathology of autism