scholarly journals The trend of the oxidants in boreal forest over 2007–2018: comprehensive modelling study with long-term measurements at SMEAR II, Finland

2020 ◽  
Author(s):  
Dean Chen ◽  
Putian Zhou ◽  
Tuomo Nieminen ◽  
Pontus Roldin ◽  
Ximeng Qi ◽  
...  
Keyword(s):  
Air Pollutants ◽  
Size Range ◽  
Chemical Components ◽  
Detailed Model ◽  
One Dimensional ◽  
The Past ◽  
Main Driver ◽  
The One ◽  
Long Term Trend

Abstract. Major atmospheric oxidants (OH, O3 and NO3) dominate the atmospheric oxidation capacity, while H2SO4 is considered as a main driver for new particle formation events. Although numerous studies have investigated the long-term trend of ozone in Europe, the trend of OH, NO3 and H2SO4 at specific sites are to a large extent unknown. In this study, we investigated how the trends in major atmospheric oxidants (OH, O3 and NO3) and H2SO4 changed in southern Finland during the past 12 years and discuss how these trends relate to decreasing emissions of regulated air pollutants in Europe. The one-dimensional model SOSAA has been applied in several studies at the SMEAR II station, and has been validated by measurements in several projects. Here, we ran the SOSAA model for the years 2007–2018 to simulate the atmospheric chemical components, especially the atmospheric oxidants and H2SO4 at SMEAR II. The simulations were evaluated with observations at SMEAR II for several shorter and longer campaigns. Our results show that OH increased by +1.56 (−0.8; +3.17) % yr−1 during daytime and NO3 decreased by −3.92 (−6.49; −1.79) % yr−1 during nighttime, indicating different trends of the oxidants during day and night. Sulphuric acid decreased during daytime by −5.12 (−11.39; −0.52) % yr−1, which correlated with the observed decreasing concentration of newly formed particles in the size range 3–25 nm by 1.4 % yr−1 at SMEAR II during the years 1997–2012 (Nieminen et al., 2014). Additionally we compared our simulated OH, NO3 and H2SO4 concentrations with proxies, which are commonly applied in case limited amount of parameters are measured and no detailed model simulations are available.

scholarly journals LONG-TERM MORPHOLOGICAL EVOLUTION MODEL

2018 ◽  
pp. 64
Author(s):  
Bradley Johnson ◽  
Jesse McNinch
Keyword(s):  
South Carolina ◽  
Morphological Evolution ◽  
Shoreline Change ◽  
One Dimensional ◽  
The Past ◽  
Longshore Transport ◽  
Model Predictions ◽  
Erosion And Accretion ◽  
The One

Nearshore morphology models predicting storm-scale erosion have been in use for the past several decades. These empirical tools typically focus on a single time-scale, which limits the utilization. For example, models developed to predict cross-shore storm erosion are poorly suited for longer-term simulations that include the beach recovery between events and gradients in longshore transport. Herein, the one-dimensional model CSHORE is extended to include shoreline change associated with along- shore variation in transport. A comparison of model predictions with long-term shoreline data from South Carolina demonstrate reasonable agreement with both erosion and accretion.

scholarly journals Fingerprint of climate change in precipitation aggressiveness across the central Mediterranean (Italian) area

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Nazzareno Diodato ◽  
Fredrik Charpentier Ljungqvist ◽  
Gianni Bellocchi
Keyword(s):  
Economic Losses ◽  
Rainfall Erosivity ◽  
Central Mediterranean ◽  
The Past ◽  
Recent Warming ◽  
Hydrological Extremes ◽  
Main Driver ◽  
The Relationship ◽  
Long Term Trend

AbstractRainfall erosivity and its derivative, erosivity density (ED, i.e., the erosivity per unit of rain), is a main driver of considerable environmental damages and economic losses worldwide. This study is the first to investigate the interannual variability, and return periods, of both rainfall erosivity and ED over the Mediterranean for the period 1680–2019. By capturing the relationship between seasonal rainfall, its variability, and recorded hydrological extremes in documentary data consistent with a sample (1981–2015) of detailed Revised Universal Soil Loss Erosion-based data, we show a noticeable decreasing trend of rainfall erosivity since about 1838. However, the 30-year return period of ED values indicates a positive long-term trend, in tandem with the resurgence of very wet days (> 95th percentile) and the erosive activity of rains during the past two decades. A possible fingerprint of recent warming is the occurrence of prolonged wet spells in apparently more erratic and unexpected ways.

scholarly journals Assessing a Linear Nanosystem's Limiting Reliability from its Components

2008 ◽  
Vol 45 (03) ◽  
pp. 879-887 ◽  
Author(s):  
Nader Ebrahimi
Keyword(s):  
Present State ◽  
Size Range ◽  
Two Dimensions ◽  
The Other ◽  
One Dimension ◽  
Present Moment ◽  
One Dimensional ◽  
The One ◽  
Fixed Moment ◽  
Nanosized Systems

Nanosystems are devices that are in the size range of a billionth of a meter (1 x 10-9) and therefore are built necessarily from individual atoms. The one-dimensional nanosystems or linear nanosystems cover all the nanosized systems which possess one dimension that exceeds the other two dimensions, i.e. extension over one dimension is predominant over the other two dimensions. Here only two of the dimensions have to be on the nanoscale (less than 100 nanometers). In this paper we consider the structural relationship between a linear nanosystem and its atoms acting as components of the nanosystem. Using such information, we then assess the nanosystem's limiting reliability which is, of course, probabilistic in nature. We consider the linear nanosystem at a fixed moment of time, say the present moment, and we assume that the present state of the linear nanosystem depends only on the present states of its atoms.

scholarly journals Air quality trends in Europe over the past decade: a first multi-model assessment

2011 ◽  
Vol 11 (7) ◽  
pp. 19029-19087 ◽  
Author(s):  
A. Colette ◽  
C. Granier ◽  
Ø. Hodnebrog ◽  
H. Jakobs ◽  
A. Maurizi ◽  
...  
Keyword(s):  
Air Quality ◽  
Management Strategies ◽  
Anthropogenic Emissions ◽  
Model Assessment ◽  
Transport Models ◽  
The Past ◽  
Current State ◽  
Primary Compounds ◽  
Long Term Trend

Abstract. We discuss the capability of current state-of-the-art chemistry and transport models to reproduce air quality trends and inter annual variability. Documenting these strengths and weaknesses on the basis of historical simulations is essential before the models are used to investigate future air quality projections. To achieve this, a coordinated modelling exercise was performed in the framework of the CityZEN European Project. It involved six regional and global chemistry-transport models (Bolchem, Chimere, Emep, Eurad, OsloCTM2 and Mozart) simulating air quality over the past decade in the Western European anthropogenic emissions hotspots. Comparisons between models and observations allow assessing the skills of the models to capture the trends in basic atmospheric constituents (NO2, O3, and PM10). We find that the trends of primary constituents are well reproduced (except in some countries – owing to their sensitivity to the emission inventory) although capturing the more moderate trends of secondary species such as O3 is more challenging. Apart from the long term trend, the modelled monthly variability is consistent with the observations but the year-to-year variability is generally underestimated. A comparison of simulations where anthropogenic emissions are kept constant is also investigated. We find that the magnitude of the emission-driven trend exceeds the natural variability for primary compounds. We can thus conclude that emission management strategies have had a significant impact over the past 10 yr, hence supporting further emission reductions strategies.

DIPHTHERIA IN THE UNITED STATES, 1959-1960

PEDIATRICS ◽  
1962 ◽  
Vol 30 (2) ◽  
pp. 194-205
Author(s):  
Theodore C. Doege ◽  
Clark W. Heath ◽  
Ida L. Sherman
Keyword(s):  
United States ◽  
Communicable Disease ◽  
Case Fatality ◽  
The United States ◽  
Surveillance Data ◽  
Term Trend ◽  
The Past ◽  
Primary Series ◽  
Long Term Trend

Diphtheria attack rates and cases, and to a much lesser extent case-fatality rates, have fallen steadily within the United States during the past 25 years. However, during 1959 and 1960 there was a halt in this long-term trend. Epidemiologic data on 868 clinical cases of diphtheria occurring in 1959 and 873 cases in 1960 were submitted to the Communicable Disease Center by 45 states. The cases and several major outbreaks tended to concentrate in the southern and southwestern states. Attack rates and deaths were highest for children under 10 years, and attack rates were more than five times greater for nonwhite children. Analysis of 1960 immunization data shows that 72% of the patients had received no immunizations. Fifty-five per cent of carriers, but only 18% of persons with bacteriologically confirmed cases, had received a primary series. Only 1 person of 58 fatal cases occurring in 1960 had received a primary series. Certain problems for future investigation, disclosed by the surveillance data, are discussed.

scholarly journals Quantitative Spectroscopy of Wolf-Rayet Stars

1988 ◽  
Vol 108 ◽  
pp. 133-140
Author(s):  
W. Schmutz
Keyword(s):  
Representative Point ◽  
Dimensional Model ◽  
Model Calculations ◽  
One Dimensional ◽  
The Past ◽  
First Results ◽  
The One ◽  
Expanding Atmospheres ◽  
New Generation ◽  
The Continuum

Advances in theoretical modeling of rapidly expanding atmospheres in the past few years made it possible to determine the stellar parameters of the Wolf-Rayet stars. This progress is mainly due to the improvement of the models with respect to their spatial extension: The new generation of models treat spherically-symmetric expanding atmospheres, i.e. the models are one-dimensional. Older models describe the wind by only one representative point. The older models are in fact ‘core-halo’ approximations. They have been introduced by Castor and van Blerkom (1970), and were extensively employed in the past (cf. e.g. Willis and Wilson, 1978; Smith and Willis, 1982). First results from new one-dimensional model calculations are published by Hillier (1984), Schmutz (1984), Hamann (1985), Hillier (1986), and Schmutz et al. (1987a); more detailed results are presented by Schmutz and Hamann (1986), Hamann and Schmutz (1987), Hillier (1987a,b), Wessolowski et al. (1987), Hillier (1987c) and Hamann et al. (1987). These results demonstrate that the step from zero- to one-dimensional calculations is essential. The important point is that the complicated interrelation between NLTE-level populations and radiation field is treated adequately (Schmutz and Hamann, 1986; Hillier, 1987). For this interrelation it is crucial to model consistently not only the line-formation region, but also the layers where the continuum is emitted. In fact, it is the core-halo approximation that causes the one-point models to fail in certain aspects.

scholarly journals The impact of adopting the euro on the Croatian economy

Notitia ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 73-89
Author(s):  
Zlatko Čehulić ◽  
Rajka Hrbić
Keyword(s):  
Positive Influence ◽  
European Countries ◽  
Economic Indicators ◽  
The Past ◽  
The Future ◽  
Term Basis ◽  
The One ◽  
The Impact

In this paper the impact of adopting the euro in Croatia is analysed using experiences of other countries which have passed through this process in the last decade and which are comparable with Croatia in many aspects. The process of adopting a currency different from the one that has been used for more than twenty years presents a very important economic question for each country. In this period preceding to adopting the euro, there is an opportunity to analyse this process in the countries which went through it in the past. The result of this paper shows the impacts of adopting the euro in the European countries. The selected countries, which are adequate for analysing the effects of adopting the euro, are: Portugal, Ireland, Greece, Spain, Slovenia, Slovakia, Estonia, Lithuania and Latvia. These countries have been selected for different reasons. The majority of these countries have some similarities with Croatia, which are shown in this paper via relevant economic indicators. These results are significant for Croatia and show a positive influence on the Croatian market on a long-term basis. This paper is relevant and has a practical basis both for Croatia and other countries which will go through this process in the future.

Middle and Late Holocene Sea-Level Changes in Eastern Maine Reconstructed from Foraminiferal Saltmarsh Stratigraphy and AMS 14C Dates on Basal Peat

1999 ◽  
Vol 52 (3) ◽  
pp. 350-359 ◽  
Author(s):  
W.Roland Gehrels
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Tidal Range ◽  
Sea Level Changes ◽  
The Past ◽  
Amplitude Fluctuations ◽  
Vertical Distributions ◽  
Low Amplitude ◽  
Long Term Trend

A relative sea-level history is reconstructed for Machiasport, Maine, spanning the past 6000 calendar year and combining two different methods. The first method establishes the long-term (103 yr) trend of sea-level rise by dating the base of the Holocene saltmarsh peat overlying a Pleistocene substrate. The second method uses detailed analyses of the foraminiferal stratigraphy of two saltmarsh peat cores to quantify fluctuations superimposed on the long-term trend. The indicative meaning of the peat (the height at which the peat was deposited relative to mean tide level) is calculated by a transfer function based on vertical distributions of modern foraminiferal assemblages. The chronology is determined from AMS 14C dates on saltmarsh plant fragments embedded in the peat. The combination of the two different approaches produces a high-resolution, replicable sea-level record, which takes into account the autocompaction of the peat sequence. Long-term mean rates of sea-level rise, corrected for changes in tidal range, are 0.75 mm/yr between 6000 and 1500 cal yr B.P. and 0.43 mm/yr during the past 1500 year. The foraminiferal stratigraphy reveals several low-amplitude fluctuations during a relatively stable period between 1100 and 400 cal yr B.P., and a sea-level rise of 0.5 m during the past 300 year.

MINERALOGY AS AN INDICATOR OF LONG-TERM CURRENT FLUCTUATIONS IN BAFFIN BAY

1966 ◽  
Vol 3 (2) ◽  
pp. 191-201 ◽  
Author(s):  
J. I. Marlowe
Keyword(s):  
Size Range ◽  
Coarse Sand ◽  
Coarse Grained ◽  
Current Fluctuations ◽  
Baffin Bay ◽  
Core Samples ◽  
The Past

A study of core samples from Baffin Bay indicates that gravel and coarse sand occur in all parts of the bay. Fragments in this size range are considered to have been transported into the area by floating ice. This coarse-grained sediment is rich in granitic detritus, but samples from an area within approximately 200 km of the Canadian coast also contain limestone fragments. The distribution of limestone fragments on the bottom coincides closely with the track of the Baffin Land current, in which icebergs originating in areas of limestone outcrop move southward through the bay. The distribution of limestone detritus in subbottom samples, however, suggests that the Baffin Land current has in the past flowed over a wider area than it does at present.

Neuropsychological Investigations of Human Amnesia: Insights Into the Role of the Medial Temporal Lobes in Cognition

2017 ◽  
Vol 23 (9-10) ◽  
pp. 732-740 ◽  
Author(s):  
Mieke Verfaellie ◽  
Margaret M. Keane
Keyword(s):  
Long Term Memory ◽  
Medial Temporal Lobes ◽  
Theoretical Understanding ◽  
Temporal Lobes ◽  
The Past ◽  
Clinical Disorders ◽  
Nuanced Understanding ◽  
The One

AbstractThe past 30 years of research on human amnesia has yielded important changes in our understanding of the role of the medial temporal lobes (MTL) in memory. On the one hand, this body of evidence has highlighted that not all types of memory are impaired in patients with MTL lesions. On the other hand, this research has made apparent that the role of the MTL extends beyond the domain of long-term memory, to include working memory, perception, and future thinking. In this article, we review the discoveries and controversies that have characterized this literature and that set the stage for a new conceptualization of the role of the MTL in cognition. This shift toward a more nuanced understanding of MTL function has direct relevance for a range of clinical disorders in which the MTL is implicated, potentially shaping not only theoretical understanding but also clinical practice. (JINS, 2017, 23, 732–740)

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