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Search Results: 1 - 10 of 401456 matches for " M. Aalto "
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Impact of Age on Surgical Outcomes after Robot Assisted Laparoscopic Hysterectomies  [PDF]
A. Eddib, S. Hughes, M. Aalto, A. Eswar, M. Erk, C. Michalik, V. Krovi, P. Singhal
Surgical Science (SS) , 2014, DOI: 10.4236/ss.2014.53018
Abstract:

Objective: To estimate the impact of patient’s age on surgical outcomes in patients undergoing robotic hysterectomy. Methods: A retrospective review of prospectively collected cohort data for a consecutive series of patients undergoing gynecologic robotic surgery. Patient’s age and perioperative variables were collected from the database, charts, and other hospital records of all patients undergoing robotic hysterectomy. Results: 399 patients underwent robotic surgery for gynecologic disease. 370 patients who were under age 70 were compared with 29 patients who were over age 70. When comparing all patients under age 70 with patients over age 70, the mean age was 48.4 and 77 (P < 0.05), mean BMI was 32.1 and 28.3 kg/m2 (P < 0.05), mean procedure time was 185 and 211 minutes (min) (P = 0.09), mean console time was 123 and 148 min (P = 0.056), mean OR (Operating room) time was 237 and 273, mean EBL (Estimated blood loss) was 71 and 65 ml (P = 0.74), Hb (Hemoglobin) drop was 1.4 and 1.2 (P = 0.45), uterine weight was 212 and 95 gm (P = 0.98), and length of stay was 1.4 and 1.6 days (P = 0.33) (Table 1). The patients over age 70, when procedures were combined, had a statistically significant lower mean BMI, uterine weight and longer Operating room (OR) time. However, when stratified by the type of procedure performed, there was no difference in surgery times among those under 70 and over 70 years of age. The elderly patients were more likely to have cancer, which was in almost half the elderly patients, and thus necessitate staging. Thus adding the performance of lymph node dissection likely resulted in the increased length of the surgery time that was noted in the combined group (Tables 1,

Hydrogen soil deposition at an urban site in Finland
M. Lallo, T. Aalto, J. Hatakka,T. Laurila
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2009,
Abstract: Hydrogen deposition velocities (vd) were estimated by field chamber measurements and model simulations. A closed-chamber method was used for soil deposition studies in Helsinki, Finland, at an urban park inhabited by broad-leaved trees. Radon tracer method was used to estimate the vd in nighttime when photochemical reactions were minimal and radon gas was concentrated in the shallow boundary layer due to exhalation from soil. A two-dimensional atmospheric model was used for the calculation of respective vd values and radon exhalation rates. The vd and radon exhalation rates were lower in winter than in summer according to all methods. The radon tracer method and the two-dimensional model results for hydrogen deposition velocity were in the range of 0.13 mm s 1 to 0.93 mm s 1 (radon tracer) and 0.12 mm s 1 to 0.61 mm s 1 (two-dimensional). The soil chamber results for vd were 0.00 mm s 1 to 0.70 mm s 1. Both models and chamber measurements revealed a relation between one week cumulative rain sum and deposition velocity. When precipitation events occurred a few days before the chamber measurements, lower vd values were observed. A snow cover also lowered vd.
Atmospheric hydrogen variations and traffic emissions at an urban site in Finland
T. Aalto, M. Lallo, J. Hatakka,T. Laurila
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2009,
Abstract: Atmospheric hydrogen (H2) mixing ratios were observed over a one year period from summer 2007 to 2008 in Helsinki, Finland. Relatively stable background values of hydrogen were occasionally observed at the site, with minimum in October and maximum between March and May. High hydrogen mixing ratios occurred simultaneously with high carbon monoxide (CO) values and coincided with high traffic flow periods. Carbon monoxide and radon (222Rn) were continuously monitored at the same site and they were used in estimation of the hydrogen emissions from traffic. The morning rush hour slope of ΔH2/ΔCO was in average 0.43±0.03 ppb (H2)/ppb (CO). After correction due to soil deposition of H2 the slope was 0.49±0.07 ppb (H2)/ppb (CO). Using this slope and CO emission statistics, a road traffic emission of about 260 t (H2)/year was estimated for Helsinki in 2007.
Assessing seasonality of boreal coniferous forest CO2 exchange by estimating biochemical model parameters from micrometeorological flux observations
T. Thum,T. Aalto,T. Laurila,M. Aurela
Biogeosciences Discussions , 2008,
Abstract: The biochemical seasonality of the northern boreal coniferous forests was investigated by means of inversion modelling using eddy covariance data. Eddy covariance data was used to optimize the biochemical model parameters. Our study sites consisted of three Scots pine (l. Pinus sylvestris) forests and one Norway spruce (l. Picea abies) forest that were located in Finland and Sweden. We obtained temperature and seasonal dependence for the biochemical model parameters: the maximum rate of carboxylation (Vc(max) and the maximum rate of electron transport (Jmax). Both of the parameters were optimized without assumptions about their mutual magnitude. The values obtained for the biochemical model parameters were similar at all the sites during summer time. To describe seasonality, different temperature fits were made for the spring, summer and autumn periods. During summer, average Jmax across the sites was 54.0 μmol m 2 s 1 (variance 31.2 μmol m 2 s-1) and Vc(max) was 12.0 μmol m 2 s 1 (variance 6.6 μmol m 2 s-1) at 17°C. The sensitivity of the model to LAI was also studied. Simulation runs were done to study the effect of the seasonality implemented in the model using different temperature fits. The impact of seasonality on annual GPP was 15%, which corresponded to an increase of 2°C in air temperature.
Chemodiversity in terpene emissions at a boreal Scots pine stand
J. B?ck,J. Aalto,M. Henriksson,H. Hakola
Biogeosciences Discussions , 2011, DOI: 10.5194/bgd-8-10577-2011
Abstract: Atmospheric chemistry in background areas is strongly influenced by natural vegetation. Coniferous forests are known to produce large quantities of volatile vapors, especially terpenes to the surrounding air. These compounds are reactive in the atmosphere, and contribute to the formation and growth of atmospheric new particles. Our aim was to analyze the variability of mono- and sesquiterpene emissions between Scots pine trees, in order to clarify the potential errors caused by using emission data obtained from only a few trees in atmospheric chemistry models. We also aimed at testing if stand history and seed origin has an influence on the chemotypic diversity. The inherited, chemotypic variability in mono- and sesquiterpene emission was studied in a seemingly homogeneous 47-yr-old stand in Southern Finland, where two areas differing in their stand regeneration history could be distinguished. Sampling was conducted in August 2009. Terpene concentrations in the air had been measured at the same site for seven years prior to branch sampling for chemotypes. Two main compounds, α-pinene and Δ3-carene formed together 40–97% of the monoterpene proportions in both the branch emissions and in the air concentrations. The data showed a bimodal distribution in emission composition, in particular in Δ3-carene emission within the studied population. 10% of the trees emitted mainly α-pinene and no Δ3-carene at all, whereas 20% of the trees where characterized as high Δ3-carene emitters (Δ3-carene forming >80% of total emitted monoterpene spectrum). An intermediate group of trees emitted equal amounts of both α-pinene and Δ3-carene. The emission pattern of trees at the area established using seeding as the artificial regeneration method differed from the naturally regenerated or planted trees, being mainly high Δ3-carene emitters. Some differences were also seen in e.g. camphene and limonene emissions between chemotypes, but sesquiterpene emissions did not differ significantly between trees. The atmospheric concentrations at the site were found to reflect the species and/or chemodiversity rather than the emissions measured from any single tree, and were strongly dominated by α-pinene. We also tested the effect of chemodiversity on modeled monoterpene concentrations at the site and found out that since it significantly influences the distributions and hence the chemical reactions in the atmosphere, it should be taken into account in atmospheric modeling.
Hydrogen soil deposition at an urban site in Finland
M. Lallo,T. Aalto,J. Hatakka,T. Laurila
Atmospheric Chemistry and Physics Discussions , 2009,
Abstract: Hydrogen deposition velocities (v_d) were estimated by field chamber measurements and model simulations. A closed-chamber method was used for soil deposition studies in Helsinki, Finland, at an urban park inhabited by broad-leaved trees. Radon tracer method was used to estimate the v_d in nighttime when photochemical reactions were minimal and radon gas was concentrated to shallow boundary layer due to exhalation from soil. A two-dimensional atmospheric model was used for calculation of respective v_d values and radon exhalation rate. v_d and radon exhalation rates were lower in winter than in summer according to all methods. The radon tracer method and two-dimensional model results for hydrogen deposition velocity were in the range of 0.13 mm s 1 to 0.90 mm s 1 (radon tracer) and 0.12 mm s 1 to 0.61 mm s 1 (two-dimensional). The soil chamber results for v_d were 0.00 mm s 1 to 0.70 mm s 1. Both models and chamber measurements revealed relation between one week cumulative rain sum and deposition velocity. Lower v_d values were usually measured in high soil moisture conditions. Precipitation occurring a few days before chamber measurements decreased v_d values. The snow cover also lowered v_d.
The analysis of size-segregated cloud condensation nuclei counter (CCNC) data and its implications for aerosol-cloud interactions
M. Paramonov,P. P. Aalto,A. Asmi,N. Prisle
Atmospheric Chemistry and Physics Discussions , 2013, DOI: 10.5194/acpd-13-9681-2013
Abstract: Ambient aerosol, CCN and hygroscopic properties were measured with a size-segregated CCNC in a~boreal environment of Southern Finland at the SMEAR II station. The instrumental setup operated at five levels of supersaturation S covering a range from 0.1 to 1% and measured particles with a size range of 20–300 nm; a total of 29 non-consecutive months of data are presented. The median critical diameter Dc ranged from 150 nm at S of 0.1% to 46 nm at S of 1.0%. The median aerosol hygroscopicity parameter κ ranged from 0.41 at S of 0.1% to 0.14 at S of 1.0%, indicating that ambient aerosol in Hyyti l is less hygroscopic than the global continental or European continental averages. It is, however, more hygroscopic than the ambient aerosol in an Amazon rainforest, a European high alpine site or a forested mountainous site. A fairly low hygroscopicity in Hyyti l is likely a result of a large organic fraction present in the aerosol mass comparative to other locations within Europe. A considerable difference in particle hygroscopicity was found between particles smaller and larger than ~100 nm in diameter, possibly pointing out to the effect of cloud processing increasing κ of particles > 100 nm in diameter. The hygroscopicity of the smaller, ~50 nm particles did not change seasonally, whereas particles with a diameter of ~150 nm showed a decreased hygroscopicity in the summer, likely resulting from the increased VOC emissions of the surrounding boreal forest and secondary organic aerosol (SOA) formation. For the most part, no diurnal patterns of aerosol hygroscopic properties were found. Exceptions to this were the weak diurnal patterns of small, ~50 nm particles in the spring and summer, when a peak in hygroscopicity around noon was observed. No difference in CCN activation and hygroscopic properties was found on days with or without atmospheric new particle formation. During all seasons, except summer, a CCN-inactive fraction was found to be present, rendering the aerosol of 75–300 nm in diameter as internally mixed in the summer and not internally mixed for the rest of the year.
One year boundary layer aerosol size distribution data from five Nordic background stations
P. Tunved,H.-C. Hansson,M. Kulmala,P. Aalto
Atmospheric Chemistry and Physics Discussions , 2003,
Abstract: Size distribution measurements performed at five different stations have been investigated during a one-year period between 01 June 2000 and 31 May 2001 with focus on diurnal, seasonal and geographical differences of size distribution properties. The stations involved cover a large geographical area ranging from the Finnish Lapland (67° N) down to southern Sweden (56° N) in the order V rri , Pallas, Hyyti l , Aspvreten and Vavihill. The shape of the size distribution is typically bimodal during winter with a larger fraction of accumulation mode particles compared to the other seasons. Highest Aitken mode concentration is found during summer and spring. The maximum of nucleation events occur during spring months. Nucleation events occur during other seasons as well, although not as frequently. Large differences were found between different categories of stations. Northerly located stations such as Pallas and V rri presented well-separated Aitken and accumulation modes, while the two modes often overlap significantly at the two southernmost stations Vavihill and Aspvreten. A method to cluster trajectories was used to analyse the impact of long-range transport on the observed aerosol properties. Clusters of trajectories arriving from the continent were clearly associated with size distributions shifted towards the accumulation mode. This feature was more pronounced the further south the station was located. Marine- or Arctic-type clusters were associated with large variability in the nuclei size ranges. A quasi-lagrangian approach was used to investigate transport related changes in the aerosol properties. Typically, an increase in especially Aitken mode concentrations was observed when advection from the north occurs, i.e. allowing more continental influence on the aerosol when comparing the different measurement sites. When trajectory clusters arrive to the stations from SW, a gradual decrease in number concentration is experienced in all modes as latitude of measurement site increases.
Atmospheric hydrogen variations and traffic emissions at an urban site in Finland
T. Aalto,M. Lallo,J. Hatakka,T. Laurila
Atmospheric Chemistry and Physics Discussions , 2009,
Abstract: Atmospheric hydrogen (H2) mixing ratios were observed over one year period from summer 2007 to 2008 in Helsinki, Finland. Relatively stable background values of hydrogen were occasionally observed at the site, with minimum in October and maximum between March and May. High hydrogen mixing ratios occurred simultaneously with high carbon monoxide (CO) values and coincided with high traffic flow periods. Carbon monoxide and radon (222Rn) were continuously monitored at the same site and they were used in estimation of the hydrogen emissions from traffic. The morning rush hour slope of ΔH2/ΔCO was in average 0.43±0.03 ppb (H2)/ppb(CO). After correction due to soil deposition of H2 the slope was 0.49±0.07 ppb (H2)/ppb(CO). Using this slope and CO emission statistics, a road traffic emission of about 260 t (H2)/year was estimated for Helsinki in 2007.
Inverse modelling of European N2O emissions: assimilating observations from different networks
M. Corazza,P. Bergamaschi,A. T. Vermeulen,T. Aalto
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2011, DOI: 10.5194/acp-11-2381-2011
Abstract: We describe the setup and first results of an inverse modelling system for atmospheric N2O, based on a four-dimensional variational (4DVAR) technique and the atmospheric transport zoom model TM5. We focus in this study on the European domain, utilizing a comprehensive set of quasi-continuous measurements over Europe, complemented by N2O measurements from the Earth System Research Laboratory of the National Oceanic and Atmospheric Administration (NOAA/ESRL) cooperative global air sampling network. Despite ongoing measurement comparisons among networks parallel measurements at a limited number of stations show that significant offsets exist among the different laboratories. Since the spatial gradients of N2O mixing ratios are of the same order of magnitude as these biases, the direct use of these biased datasets would lead to significant errors in the derived emissions. Therefore, in order to also use measurements with unknown offsets, a new bias correction scheme has been implemented within the TM5-4DVAR inverse modelling system, thus allowing the simultaneous assimilation of observations from different networks. The N2O bias corrections determined in the TM5-4DVAR system agree within ~0.1 ppb (dry-air mole fraction) with the bias derived from the measurements at monitoring stations where parallel NOAA discrete air samples are available. The N2O emissions derived for the northwest European and east European countries for 2006 show good agreement with the bottom-up emission inventories reported to the United Nations Framework Convention on Climate Change (UNFCCC). Moreover, the inverse model can significantly narrow the uncertainty range reported in N2O emission inventories for these countries, while the lack of measurements does not allow to reduce the uncertainties of emission estimates in southern Europe. Several sensitivity experiments were performed to test the robustness of the results. It is shown that also inversions without detailed a priori spatio-temporal emission distributions are capable to reproduce major regional emission patterns within the footprint of the existing atmospheric network, demonstrating the strong constraints of the atmospheric observations on the derived emissions.
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