Sediment Nutrient Accumulation and Nutrient Availability in Two Tidal Freshwater Marshes Along the Mattaponi River, Virginia, USA

Sediment deposition is the main mechanism of nutrient delivery to tidal freshwater marshes (TFMs). We quantified sediment nutrient accumulation in TFMs upstream and downstream of a proposed water withdrawal project on the Mattaponi River, Virginia. Our goal was to assess nutrient availability by comparing relative rates of carbon (C), nitrogen (N), and phosphorus (P) accumulated in sediments with the C, N, and P stoichiometries of surface soils and above ground plant tissues. Surface soil nutrient contents (0.60–0.92% N and 0.09–0.13% P) were low but within reported ranges for TFMs in the eastern US. In both marshes, soil nutrient pools and C, N, and P stoichiometries were closely associated with sedimentation patterns. Differences between marshes were more striking than spatial variations within marshes: both C, N, and P accumulation during summer, and annual P accumulation rates (0.16 and 0.04 g P m−2 year−1, respectively) in sediments were significantly higher at the downstream than at the upstream marsh. Nitrogen:P ratiosbiomass, surface soils, and sediments suggest that N limits primary production in these marshes, but experimental additions of N and/or P did not significantly increase above ground productivity in either marsh. Lower soil N:P ratios are consistent with higher rates of sediment P accumulation at the downstream site, perhaps due to its greater proximity to the estuarine turbidity maximum

Cumulative Human Impacts on Mediterranean and Black Sea Marine Ecosystems: Assessing Current Pressures and Opportunities

Management of marine ecosystems requires spatial information on current impacts. In several marine regions, including the Mediterranean and Black Sea, legal mandates and agreements to implement ecosystem-based management and spatial plans provide new opportunities to balance uses and protection of marine ecosystems. Analyses of the intensity and distribution of cumulative impacts of human activities directly connected to the ecological goals of these policy efforts are critically needed. Quantification and mapping of the cumulative impact of 22 drivers to 17 marine ecosystems reveals that 20% of the entire basin and 60-99% of the territorial waters of EU member states are heavily impacted, with high human impact occurring in all ecoregions and territorial waters. Less than 1% of these regions are relatively unaffected. This high impact results from multiple drivers, rather than one individual use or stressor, with climatic drivers (increasing temperature and UV, and acidification), demersal fishing, ship traffic, and, in coastal areas, pollution from land, accounting for a majority of cumulative impacts. These results show that coordinated management of key areas and activities could significantly improve the condition of these marine ecosystems.JRC.H.1-Water Resource

A liquid helium target system for a measurement of parity violation in neutron spin rotation

A liquid helium target system was designed and built to perform a precision measurement of the parity-violating neutron spin rotation in helium due to the nucleon-nucleon weak interaction. The measurement employed a beam of low energy neutrons that passed through a crossed neutron polarizer--analyzer pair with the liquid helium target system located between them. Changes between the target states generated differences in the beam transmission through the polarizer--analyzer pair. The amount of parity-violating spin rotation was determined from the measured beam transmission asymmetries. The expected parity-violating spin rotation of order $10^{-6}$ rad placed severe constraints on the target design. In particular, isolation of the parity-odd component of the spin rotation from a much larger background rotation caused by magnetic fields required that a nonmagnetic cryostat and target system be supported inside the magnetic shielding, while allowing nonmagnetic motion of liquid helium between separated target chambers. This paper provides a detailed description of the design, function, and performance of the liquid helium target system.Comment: V2: 29 pages, 14 figues, submitted to Nucl. Instrum. Meth. B. Revised to address reviewer comment

Assessment of Existing Steel Structures - Recommendations for Estimation of the Remaining Fatigue Life

Due to the demand for freight volume on rail and road, traffic has increased significantly in the past years leading to an increasing number of heavy vehicles in the traffic flows and greater exploitation of their loading capacities. Because of environmental considerations there is also a tendency to further enhance the admissible loads in the design of new heavy vehicles (e.g. by increasing axle loads or using road trains). This all may affect the safety, serviceability and durability of existing bridges. Bridge authorities are therefore interested in agreed methods to assess the safety and durability of existing bridges and to make appropriate provisions for more refined maintenance methods, possible restriction of traffic, bridge-rehabilitation or substitution of old bridges by new ones where necessary. For steel bridges including the old riveted ones there are numerous approaches to such assessments, partly standardized by national codes or recommendations. In the light of the development of the European single market for construction works and engineering services there is thus a need to harmonize them and to develop agreed European technical recommendations for the safety and durability assessment of existing structures. These recommendations should follow the principles and application rules in the Eurocodes and provide a scheme with different levels of analysis: a basic level with general methods and further levels with higher sophistication that call for specific expertise. This technical report on ¿Recommendations for the estimation of remaining fatigue life¿ supported by the ECCS could be used as a basis for harmonizing National procedures and for the further evolution of the Eurocodes.JRC.G.5-European laboratory for structural assessmen

Proposed Subtypes of Anger Rumination: Brooding and Reflection and Their Associations with Aggression

Rumination maintains, exacerbates, and is related to several maladaptive outcomes including negative affect (e.g., sadness, anger), symptoms of depression, and aggression in samples of nonclinical and clinical populations across developmental periods (e.g., McLaughlin & Nolen-Hoeksema, 2011; Nolen-Hoeksema, 1991; Nolen-Hoeksema, 1996; Thomsen, 2006; Peled & Moretti, 2007; Yang, et. al., 2014). Recently, the construct of sadness rumination has been conceptualized as two distinct subtypes, reflection and brooding (Treynor, Gonzalez, & Nolen-Hoeksema, 2003). Brooding is considered maladaptive because feelings and situations are viewed through a negativistic lens and reflection is viewed as adaptive and uses a problem-solving approach (Lopez, 2010; Burwell & Shirk, 2007; Smith & Alloy, 2009; Treynor, et al., 2003). The current study aimed to expand upon this past research and examine whether a two-factor model of rumination (brooding and reflection) is relevant for anger rumination and examine which subtype is associated with different forms of aggression. Results revealed that a two-factor model of anger rumination was a better fit than a one-factor model. Furthermore, this study found that brooding significantly associated with increases in physical and relational aggression and reflection was significantly associated with decreases in physical and relational aggression. However, reflection and not brooding was determined to be significantly associated with elevated levels of verbal aggression. Importantly, sex did not moderate the relationship between brooding and the different forms of aggression. Overall, these findings provide evidence of brooding and reflection subtypes for anger rumination and increases the specificity of how risk factors for aggression are conceptualized, thus informing future directions for research and treatment

Small scale mining possibilities in southeast Missouri

The disseminated lead ore bodies of St. Francois County in southeast Missouri are known for their enormous size and even grade over large areas. Several of these ore bodies are over a mile long by a quarter mile wide. They have been worked on a commensurate scale. The smallest mill in the district, at Bonne Terre, now treats 2,500 tons daily capacity. Each of these mills is supplied by a single ore hoisting shaft. The disseminated ore district of St. Francois County is bounded by the Big River-Bonne Terre fault on the north and west, by the Simms Mountain fault to the west and south, and by the Farmington anticline to the east. Each side of this triangle is about twelve miles long. This district is commonly spoken of as the Lead Belt . About twenty five miles to the south, at Mine La Motte is a district several miles square of somewhat similar characteristics. This has not been a producer since 1930, but has produced a very large amount of ore in the past --Introduction, page 1

Spatial and temporal changes in cumulative human impacts on the world's ocean

Human pressures on the ocean are thought to be increasing globally, yet we know little about their patterns of cumulative change, which pressures are most responsible for change, and which places are experiencing the greatest increases. Managers and policymakers require such information to make strategic decisions and monitor progress towards management objectives. Here we calculate and map recent change over 5 years in cumulative impacts to marine ecosystems globally from fishing, climate change, and ocean- and land-based stressors. Nearly 66% of the ocean and 77% of national jurisdictions show increased human impact, driven mostly by climate change pressures. Five percent of the ocean is heavily impacted with increasing pressures, requiring management attention. Ten percent has very low impact with decreasing pressures. Our results provide large-scale guidance about where to prioritize management efforts and affirm the importance of addressing climate change to maintain and improve the condition of marine ecosystems