123 research outputs found
Clinical Relevance of Adolescent OCP Use and Depression Risk
Prevalence of depression within the United States has risen significantly in recent years.1 Depression in females has increased by 12 percent compared to 3.8 percent in males between 2009 and 2019.3 Hormonal contraceptives are widely used by women throughout the world and often started as early as menarche. Traditionally intended to prevent unwanted pregnancies, contraceptives are frequently used in the symptom management of menorrhagia and dysmenorrhea in females.2 Oral contraceptive pills (OCP) are a popular choice for adolescents due to their ease of use, formulation varieties, and ability to be used long-term. Considering the widespread use, the adverse effects can have significant clinical relevance.3 OCPs have a wide variety of side effects - including mood changes; however, there is no clear consensus among researchers and clinicians on the associations between OCP use and risk of depression.2 Nevertheless, mood changes are a common reason for discontinuation of OCPs. Further investigation into the possible connection between hormonal contraceptive use and depression may offer insight into the prevalence of depression in adolescent females compared to adolescent males and should be taken into consideration by clinicians. Overall, medical providers should be better equipped to address these concerns with their patients. The purpose of this study is to conduct a literature review based on global studies investigating possible correlation between the use of hormonal contraceptives in adolescent females and subsequent mood changes, such as depression
Atmospheric Deposition on Swiss Long-Term Forest Ecosystem Research (LWF) Plots
Atmospheric deposition of the major elements was estimated from throughfall and bulk deposition measurements on 13 plots of the Swiss Long-Term Forest Ecosystem Research (LWF) between 1995 and 2001. Independent estimates of the wet and dry deposition of nitrogen (N) and sulfur (S) on these same plots were gained from combined simplified models. The highest deposition fluxes were measured at Novaggio (Southern Switzerland), exposed to heavy air pollution originating from the Po Plain, with throughfall fluxes averaging 29 kg ha−1 a−1 for N and 15 kg ha−1 a−1 for S. Low deposition fluxes were measured on the plots above 1800 m, with throughfall fluxes lower than 4.5 kg ha−1 a−1 for N and lower than 3 kg ha−1 a−1 for S. The wet deposition of N and S derived from bulk deposition was close to the modeled wet deposition, but the dry deposition derived from throughfall was significantly lower than the modeled dry deposition for both compounds. However, both the throughfall method and the model yielded total deposition estimates of N which exceeded the critical loads calculated on the basis of long-term mass balance considerations. These estimates were within or above the range of empirical critical loads except above 1800
A decade of monitoring at Swiss Long-Term Forest Ecosystem Research (LWF) sites: can we observe trends in atmospheric acid deposition and in soil solution acidity?
Trends in atmospheric acid deposition and in soil solution acidity from 1995 or later until 2007 were investigated at several forest sites throughout Switzerland to assess the effects of air pollution abatements on deposition and the response of the soil solution chemistry. Deposition of the major elements was estimated from throughfall and bulk deposition measurements at nine sites of the Swiss Long-Term Forest Ecosystem Research network (LWF) since 1995 or later. Soil solution was measured at seven plots at four soil depths since 1998 or later. Trends in the molar ratio of base cations to aluminum (BC/Al) in soil solutions and in concentrations and fluxes of inorganic N (NO3-N + NH4-N), sulfate (SO4-S), and base cations (BC) were used to detect changes in soil solution chemistry. Acid deposition significantly decreased at three out of the nine study sites due to a decrease in total N deposition. Total SO4-S deposition decreased at the nine sites, but due to the relatively low amount of SO4-S load compared to N deposition, it did not contribute to decrease acid deposition significantly. No trend in total BC deposition was detected. In the soil solution, no trend in concentrations and fluxes of BC, SO4-S, and inorganic N were found at most soil depths at five out of the seven sites. This suggests that the soil solution reacted very little to the changes in atmospheric deposition. A stronger reduction in base cations compared to aluminum was detected at two sites, which might indicate that acidification of the soil solution was proceeding faster at these site
An overview of atmospheric deposition chemistry over the Alps: present status and long-term trends
Several research programs monitoring atmospheric deposition have been launched in the Alpine countries in the last few decades. This paper uses data from previous and ongoing projects to: (i) investigate geographical variability in wet deposition chemistry over the Alps; (ii) assess temporal trends of the major chemical variables in response to changes in the atmospheric emission of pollutants; (iii) discuss the potential relationship between the status of atmospheric deposition and its effects on forest ecosystems in the alpine and subalpine area, focusing particularly on nitrogen input. We also present results of studies performed at a local level on specific topics such as long-term changes in lead deposition and the role of occult deposition in total nitrogen input. The analysis performed here highlights the marked geographical variability of atmospheric deposition in the Alpine region. Apart from some evidence of geographically limited effects, due to local sources, no obvious gradients were identified in the major ion deposition. The highest ionic loads were recorded in areas in the foothills of the Alps, such as the pre-alpine area in North-Western Italy and the area of Canton Ticino, Switzerland. Trend analysis shows a widespread decrease in the acidity of precipitation in the last 15–20 years as a consequence of the reduced emission of S compounds. On the other hand, nitrate concentrations in rain have not changed so much, and ammonium has decreased significantly only at the Austrian sampling sites. The deposition of N is still well above the estimated critical loads of nutrient N at some forest sites in the alpine and subalpine areas, thus confirming the critical situation of both terrestrial and aquatic ecosystems regarding N inputs. Existing data highlights the importance of continuously monitoring atmospheric deposition chemistry in the Alpine area, taking account of acidifying elements, nutrients and other pollutants such as heavy metals and organic compounds. There is also a need for unifying sampling and analytical methods in order to obtain comparable data from the different regions of the Alps
Atmospheric Deposition and Ozone Levels in Swiss Forests: Are Critical Values Exceeded?
Air pollution affects forest health through atmospheric deposition of acidic and nitrogen compounds and elevated levels of tropospheric ozone (O3). In 1985, a monitoring network was established across Europe and various research efforts have since been undertaken to define critical values. We measured atmospheric deposition of acidity and nitrogen as well as ambient levels of O3 on 12, 13, and 14 plots, respectively, in the framework of the Swiss Long-Term Forest Ecosystem Research (LWF) in the period from 1995 to 2002. We estimated the critical loads of acidity and of nitrogen, using the steady state mass balance approach, and calculated the critical O3 levels using the AOT40 approach. The deposition of acidity exceeded the critical loads on 2 plots and almost reached them on 4 plots. The median of the measured molar ratio of base nutrient cations to total dissolved aluminium (Bc/Al) in the soil solution was higher than the critical value of 1 for all depths, and also at the plots with an exceedance of the critical load of acidity. For nitrogen, critical loads were exceeded on 8 plots and deposition likely represents a long-term ecological risk on 3 to 10 plots. For O3, exceedance of critical levels was recorded on 12 plots, and led to the development of typical O3-induced visible injury on trees and shrubs, but not for all plots due to (1) the site specific composition of O3 sensitive and tolerant plant species, and (2) the influence of microclimatic site conditions on the stomatal behaviour, i.e., O3 uptak
Response of carbon fluxes to the 2003 heat wave and drought in three mature forests in Switzerland
The effects of the heat and drought of the summer 2003 on carbon (C) fluxes (soil CO2 efflux, dissolved organic carbon in soil, C from litterfall and C sequestration in tree) were investigated in three mature forests in Switzerland between 2001 and 2005. Measurements of the soil matric potential (Ψ) indicated a gradient in drought intensity at the three sites (Vordemwald, Schänis, Beatenberg) with average Ψ during the summer 2003 of −75, −41 and −5kPa, respectively. In Vordemwald where the drought was the most severe, the hourly soil CO2 efflux declined by about 30% when Ψ<−90kPa. Estimated annual soil CO2 efflux in 2003 was about 10% smaller than effluxes in wetter years (2001, 2002 and 2004) but the differences were not significant. In Schänis and Beatenberg, no suppression of hourly soil CO2 efflux was observed during the summer 2003. The annual efflux in 2003 at both sites was 10-15% larger than the effluxes in the other years but the differences were not significant. DOC concentrations increased during the first rewetting events after the drought in Vordemwald and in Schänis. This was mainly due to a concentration effect due to the low soil water content. Because precipitation was lower in 2003, annual DOC fluxes substantially decreased at the three sites. Carbon sequestration in tree stems in Vordemwald declined by 32% in 2003 compared to the mean 2002-2005. In Beatenberg and Schänis, tree growth responded little to the extreme summer 2003. Litterfall at the three sites showed no marked reaction to the summer 2003. Estimate of annual net ecosystem production (NEP) suggested that the stands in Vordemwald and in Schänis remained a C sink between 2002 and 2005 but that the extreme summer 2003 caused a decrease in NEP. In Beatenberg, the impact on the NEP seemed to be limited in 2003. The annual NEP in 2003 decreased with increasing drought intensity over the three site
Does exceeding the critical loads for nitrogen alter nitrate leaching, the nutrient status of trees and their crown condition at Swiss Long-term Forest Ecosystem Research (LWF) sites?
Nitrogen (N) deposition exceeds the critical loads for this element in most parts of Switzerland apart from the Alps. At 17 sites (8 broadleaved stands, 8 coniferous stands, and 1 mixed stand) of the Swiss Long-term Forest Ecosystem Research network, we are investigating whether N deposition is associated with the N status of the forest ecosystems. N deposition, assessed from throughfall measurements, was related to the following indicators: (1) nitrate leaching below the rooting zone (measured on a subset of 9 sites); (2) the N nutrition of the forest stand based on foliar analyses (16 sites); and (3) crown defoliation, a non specific indicator of tree vitality (all 17 sites). Nitrate leaching ranging from about 2 to 16kgNha−1a−1 was observed at sites subjected to moderate to high total N deposition (>10kgha−1a−1). The C/N ratio of the soil organic layer, or, when it was not present, of the upper 5cm of the mineral soil, together with the pool of organic carbon in the soil, played a critical role, as previous studies have also found. In addition, the humus type may need to be considered as well. For instance, little nitrate leaching (30kgha−1a−1) but characterized by a C/N ratio of 24, large organic C stocks, and a moder humus type. Foliar N concentrations correlated with N deposition in both broadleaved and coniferous stands. In half of the coniferous stands, foliar N concentrations were in the deficiency range. Crown defoliation tended to be negatively correlated with N concentrations in the needles. In the majority of the broadleaved stands, foliar N concentrations were in the optimum nutritional range or, on one beech plot with high total N deposition (>25kgha−1a−1), above the optimum values. There was no correlation between the crown defoliation of broadleaved trees and foliar concentration
Good Agreement Between Modeled and Measured Sulfur and Nitrogen Deposition in Europe, in Spite of Marked Differences in Some Sites
Atmospheric nitrogen and sulfur deposition is an important effect of atmospheric pollution and may affect forest ecosystems positively, for example enhancing tree growth, or negatively, for example causing acidification, eutrophication, cation depletion in soil or nutritional imbalances in trees. To assess and design measures to reduce the negative impacts of deposition, a good estimate of the deposition amount is needed, either by direct measurement or by modeling. In order to evaluate the precision of both approaches and to identify possible improvements, we compared the deposition estimates obtained using an Eulerian model with the measurements performed by two large independent networks covering most of Europe. The results are in good agreement (bias <25%) for sulfate and nitrate open field deposition, while larger differences are more evident for ammonium deposition, likely due to the greater influence of local ammonia sources. Modeled sulfur total deposition compares well with throughfall deposition measured in forest plots, while the estimate of nitrogen deposition is affected by the tree canopy. The geographical distribution of pollutant deposition and of outlier sites where model and measurements show larger differences are discussed
A comparison of global agricultural monitoring systems and current gaps
Global and regional scale agricultural monitoring systems aim to provide up-to-date information regarding food production to different actors and decision makers in support of global and national food security. To help reduce price volatility of the kind experienced between 2007 and 2011, a global system of agricultural monitoring systems is needed to ensure the coordinated flow of information in a timely manner for early warning purposes. A number of systems now exist that fill this role. This paper provides an overview of the eight main global and regional scale agricultural monitoring systems currently in operation and compares them based on the input data and models used, the outputs produced and other characteristics such as the role of the analyst, their interaction with other systems and the geographical scale at which they operate. Despite improvements in access to high resolution satellite imagery over the last decade and the use of numerous remote-sensing based products by the different systems, there are still fundamental gaps. Based on a questionnaire, discussions with the system experts and the literature, we present the main gaps in the data and in the methods. Finally, we propose some recommendations for addressing these gaps through ongoing improvements in remote sensing, harnessing new and innovative data streams and the continued sharing of more and more data
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