73 research outputs found
Scavenging of ultrafine particles by rainfall at a boreal site: observations and model estimations
International audienceValues of the scavenging coefficient were determined from observations of ultrafine particles (with diameters in the range 10?510 nm) during rain events at a boreal forest site in Southern Finland between 1996 and 2001. The estimated range of values of the scavenging coefficient was [7Ă—10?6?4Ă—10?5] s?1, which is generally higher than model calculations based only on below-cloud processes (Brownian diffusion, interception, and typical charge effects). A new model that includes below-cloud scavenging processes, mixing of ultrafine particles from the boundary layer (BL) into cloud, followed by cloud condensation nuclei activation and in-cloud removal by rainfall, is presented. The effective scavenging coefficients estimated from this new model have values comparable with those obtained from observations. Results show that ultrafine particle removal by rain depends on aerosol size, rainfall intensity, mixing processes between BL and cloud elements, in-cloud scavenged fraction, in-cloud collection efficiency, and in-cloud coagulation with cloud droplets. Implications for the treatment of scavenging of BL ultrafine particles in numerical models are discussed
Waterfalls as sources of small charged aerosol particles
In this study, we measured the mobility distributions of cluster and intermediate ions with an ion spectrometer near a waterfall. We observed that the concentration of negative 1.5–10 nm ions was one-hundred fold higher than a reference point 100 m away from the waterfall. Also, the concentration of positive intermediate ions was found to be higher than that at the reference point by a factor of ten. This difference was observed only at the smallest sizes; above 10 nm the difference was insignificant
Non-curative treatment of patients with oral tongue squamous-cell carcinoma
PurposeLate-stage OTSCC is associated with poor overall survival (OS). Non-curative treatment approach aims to improve quality of life and prolong survival of patients deemed incurable. The purpose of this study was to investigate the used non-curative treatment modalities for OTSSC and patient survival.MethodsAll patients diagnosed with OTSCC and treated with non-curative intent at the HUS Helsinki University Hospital (Helsinki, Finland) during the 12-year period of 2005-2016 were included. Survival analysis after the non-curative treatment decision was conducted using the Kaplan-Meier method in this population-based study.ResultsEighty-two patients were identified. A non-curative treatment decision was made at presentation without any previous treatment in 26 patients (7% of all patients diagnosed with OTSCC during the study period). Palliative radiotherapy was administered to 24% of all patients. The average survival time after the non-curative treatment decision was 3.7months (median 2 and range 0-26).ConclusionsDue to the short mean survival time after decision for treatment with non-curative intent, and the notable symptom burden in this patient population, a prompt initiation of all non-curative measures is warranted.Peer reviewe
Effects of Initial Age Structure of Managed Norway Spruce Forest Area on Net Climate Impact of Using Forest Biomass for Energy
We investigated how the initial age structure of a managed, middle boreal (62A degrees N), Norway spruce-dominated (Picea abies L. Karst.) forest area affects the net climate impact of using forest biomass for energy. The model-based analysis used a gap-type forest ecosystem model linked to a life cycle assessment (LCA) tool. The net climate impact of energy biomass refers to the difference in annual net CO2 exchange between the biosystem using forest biomass (logging residues from final felling) and the fossil (reference) system using coal. In the simulations over the 80-year period, the alternative initial age structures of the forest areas were (i) skewed to the right (dominated by young stands), (ii) normally distributed (dominated by middle-aged stands), (iii) skewed to the left (dominated by mature stands), and (iv) evenly distributed (same share of different age classes). The effects of management on net climate impacts were studied using current recommendations as a baseline with a fixed rotation period of 80 years. In alternative management scenarios, the volume of the growing stock was maintained 20% higher over the rotation compared to the baseline, and/or nitrogen fertilization was used to enhance carbon sequestration. According to the results, the initial age structure of the forest area affected largely the net climate impact of using energy biomass over time. An initially right-skewed age structure produced the highest climate benefits over the 80-year simulation period, in contrast to the left-skewed age structure. Furthermore, management that enhanced carbon sequestration increased the potential of energy biomass to replace coal, reducing CO2 emissions and enhancing climate change mitigation.Peer reviewe
Non-curative treatment of patients with oral tongue squamous-cell carcinoma
PurposeLate-stage OTSCC is associated with poor overall survival (OS). Non-curative treatment approach aims to improve quality of life and prolong survival of patients deemed incurable. The purpose of this study was to investigate the used non-curative treatment modalities for OTSSC and patient survival.MethodsAll patients diagnosed with OTSCC and treated with non-curative intent at the HUS Helsinki University Hospital (Helsinki, Finland) during the 12-year period of 2005–2016 were included. Survival analysis after the non-curative treatment decision was conducted using the Kaplan–Meier method in this population-based study.ResultsEighty-two patients were identified. A non-curative treatment decision was made at presentation without any previous treatment in 26 patients (7% of all patients diagnosed with OTSCC during the study period). Palliative radiotherapy was administered to 24% of all patients. The average survival time after the non-curative treatment decision was 3.7 months (median 2 and range 0–26).ConclusionsDue to the short mean survival time after decision for treatment with non-curative intent, and the notable symptom burden in this patient population, a prompt initiation of all non-curative measures is warranted.</div
A look at aerosol formation using data mining techniques
International audienceAtmospheric aerosol particle formation is frequently observed throughout the atmosphere, but despite various attempts of explanation, the processes behind it remain unclear. In this study data mining techniques were used to find the key parameters needed for atmospheric aerosol particle formation to occur. A dataset of 8 years of 80 variables collected at the boreal forest station (SMEAR II) in Southern Finland was used, incorporating variables such as radiation, humidity, SO2, ozone and present aerosol surface area. Data analysis were done using clustering and classification methods. The aim of this approach was to gain new parameters independent of any subjective interpretation. This resulted in two key parameters, relative humidity and preexisting aerosol particle surface (condensation sink), capable in explaining 88% of the nucleation events. The inclusion of any further parameters did not improve the results notably. Using these two variables it was possible to derive a nucleation probability function. Interestingly, the two most important variables are related to mechanisms that prevent the nucleation from starting and particles from growing, while parameters related to initiation of particle formation seemed to be less important. Nucleation occurs only with low relative humidity and condensation sink values. One possible explanation for the effect of high water content is that it prevents biogenic hydrocarbon ozonolysis reactions from producing sufficient amounts of low volatility compounds, which might be able to nucleate. Unfortunately the most important biogenic hydrocarbon compound emissions were not available for this study. Another effect of water vapour may be due to its linkage to cloudiness which may prevent the formation of nucleating and/or condensing vapours. A high number of preexisting particles will act as a sink for condensable vapours that otherwise would have been able to form sufficient supersaturation and initiate the nucleation process
Cognitive Effects of White Matter Pathology in Normal and Pathological Aging
We examined whether cerebrovascular white matter pathology is related to cognition as measured by the compound score of CERAD neuropsychological battery in cognitively normal older adults, patients with mild cognitive impairment, and patients with Alzheimer's disease (total n = 149), controlling for age and education. Trend-level effects of white matter pathology on cognition were only observed in patients with Alzheimer's disease (p = 0.062, eta(2) = 0.052), patients with severe frontal white matter pathology performed notably worse than those with milder pathology. This indicates that frontal cerebrovascular pathology may have an additive negative effect on cognition in Alzheimer's disease
New insights into nocturnal nucleation
Formation of new aerosol particles by nucleation and growth is a significant source of aerosols in the atmosphere. New particle formation events usually take place during daytime, but in some locations they have been observed also at night. In the present study we have combined chamber experiments, quantum chemical calculations and aerosol dynamics models to study nocturnal new particle formation. All our approaches demonstrate, in a consistent manner, that the oxidation products of monoterpenes play an important role in nocturnal nucleation events. By varying the conditions in our chamber experiments, we were able to reproduce the very different types of nocturnal events observed earlier in the atmosphere. The exact strength, duration and shape of the events appears to be sensitive to the type and concentration of reacting monoterpenes, as well as the extent to which the monoterpenes are exposed to ozone and potentially other atmospheric oxidants
Holistic evaluation of the environmental impacts of shipping in the sensitive region of Ria de Aveiro
© 2024 The Authors. Published by Elsevier B.V. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/Shipping activity can be a substantial source of pollution and impact on the environment, including air, water and ecosystems, as well as adverse health and climatic effects. Due to the distribution of maritime transport activity routes in the EU, a large portion of the population is exposed to shipping pollution throughout Europe. The ongoing European project EMERGE aims to investigate and quantify these impacts over Europe, and in more detail, in specific case studies regions. The Aveiro lagoon region in Portugal is one of these case studies. This region is a Natura 2000 area, and also includes a medium-sized port. Both air quality and water modelling tools were applied to assess the impact of the emissions and discharges from shipping (to air and water) in the region in 2018. Additionally, ecotoxicological impacts were determined by bioassays to evaluate the impact of scrubber-water discharges on the most sensitive stages of marine invertebrates, and on the post-exposure feeding inhibition of crustacean and bivalve species. The results show that there was a substantial increase in atmospheric pollutant concentrations due to emissions attributed to shipping, which was most relevant for NOx and SO2 (up to a 30 % shipping contribution). There was no significant degradation of the water quality, mainly as the ships operating in this area did not have scrubber equipment. The ecotoxicological tests were performed with three samples of scrubber water, including one artificial sample and two samples collected on-board ships. If scrubber water would have been discharged in this area, the results indicated that the majority of the tested species would be exposed to lowest observed effect concentration (LOEC) for the different scrubber-water samples, as well as to substantial concentrations of metals, PAHs, and alkylated PAHs.Peer reviewe
The impact of the duration of the palliative care period on cancer patients with regard to the use of hospital services and the place of death: a retrospective cohort study
Background: In order to avoid unnecessary use of hospital services at the end-of-life, palliative care should be initiated early enough in order to have sufficient time to initiate and carry out good quality advance care planning (ACP). This single center study assesses the impact of the PC decision and its timing on the use of hospital services at EOL and the place of death. Methods: A randomly chosen cohort of 992 cancer patients treated in a tertiary hospital between Jan 2013 -Dec 2014, who were deceased by the end of 2014, were selected from the total number of 2737 identified from the hospital database. The PC decision (the decision to terminate life-prolonging anticancer treatments and focus on symptom centered palliative care) and use of PC unit services were studied in relation to emergency department (ED) visits, hospital inpatient days and place of death. Results: A PC decision was defined for 82% of the patients and 37% visited a PC unit. The earlier the PC decision was made, the more often patients had an appointment at the PC unit (> 180 days prior to death 72% and Conclusions: The PC decision to initiate a palliative goal for the treatment had a distinct impact on the use of hospital services at the EOL. Contact with a PC unit further increased the likelihood of EOL care at primary care.</div
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