Northern Quahog (Hard Clam) Mercenaria Mercenaria Abundance And Habitat Use In Chesapeake Bay

Recent (2001-2002) surveys of hard clam Mercenaria mercenaria density and distribution, using patent tongs in a stratified random design (n = 7,358 stations) in lower Chesapeake Bay are not consistent with historic descriptions of clam habitats and densities. The highest average densities observed, up to 3.1 clams m(-2), were in the lower James River. The highest modern average density observed is half that of clam densities commonly observed in these same habitats during the early 1970s. Current distribution is significantly affected by water depth and substrate composition. Hard clam density in Chesapeake Bay is positively associated with increasing sediment grain size; 78% of all clams collected were found in shell or sand habitats. However, 44% of sand habitats and 54% of shell habitats were unoccupied suggesting that even habitat types that typically support higher clam densities may currently be underused

An eco-approach to optimise efficiency and productivity of a hydraulic excavator

The depletion of fossil fuel and the ozone layer has been a global concern for decades. The International Organization for Standardization has published earth-moving machine sustainability standards for the industry to provide information to satisfy their customers' interests in their construction projects. Furthermore, steeply rising energy prices and the collapse of financial institutions in recent years have sparked demand for ways to improve individual energy efficiency. Original equipment manufacturers of earth-moving machines must address sustainability requirements, as well as remaining competitive and they aim to do this by improving machine efficiency, adopting advanced fleet management systems, providing operator training courses etc. Clearly high fuel efficiency is important to reduce depletion of fossil fuels and damage to the environment. However, the objectives of achieving the highest possible productivity (m³/h) and improving fuel efficiency (kg/l) are often considered separately. Many equations have been formulated to measure a machine's highest possible productivity level, yet there is a lack of consensus between academia and industry sources on the terms which should be considered within such equations. Perhaps more importantly, none have explicitly considered the relationship between fuel efficiency and productivity, and only scant consideration is given to the role of operators in achieving optimum productivity for fuel efficiency. Therefore, this paper presents an eco-approach to enable operators to achieve optimal productivity for fuel efficiency of a hydraulic excavator. Hydraulic excavators are primarily designed for excavating with a bucket. Their ease of use, versatility and high productivity have won them major segments of the construction equipment market, therefore the focus on hydraulic exactors in this paper is justifiable. The research presented in this paper has adopted an applied research methodology to collect measurable, empirical evidence through scientific experiments in order to test several hypotheses that focus on the reduction of GHG produced by construction machines. The research has examined two variables, engine speed and bucket cut depth, to determine their effects on productivity and fuel efficiency of a hydraulic excavator. The experimental results show that the combinations of various engine speed settings and bucket cut depths can increase productivity by 30% and cut greenhouse gas emissions by 24%, consequentially moving 62% more spoil every hour for every litre of fuel consumed. The results also suggest that identifying the correct bucket cut depth is the key to significant improvements in productivity and reduction in greenhouse gas emissions. The paper therefore concludes that adoption of an appropriate construction machine operation style can help reduce the greenhouse gas emissions associated with hydraulic excavators. Hence, educating operators to select the right engine speed and bucket cut depth is a cost effective approach to lowering the operational costs and carbon emissions through lower fuel consumption and greater machine longevity

Industrial cyber physical systems supported by distributed advanced data analytics

The industry digitization is transforming its business models, organizational structures and operations, mainly promoted by the advances and the mass utilization of smart methods, devices and products, being leveraged by initiatives like Industrie 4.0. In this context, the data is a valuable asset that can support the smart factory features through the use of Big Data and advanced analytics approaches. In order to address such requirements and related challenges, Cyber Physical Systems (CPS) promote the development of more intelligent, adaptable and responsiveness supervisory and control systems capable to overcome the inherent complexity and dynamics of industrial environments. In this context, this work presents an agent-based industrial CPS, where agents are endowed with data analysis capabilities for distributed, collaborative and adaptive process supervision and control. Additionally, to address the different industrial levels’ requirements, this work combines two main data analysis scopes: at operational level, applying distributed data stream analysis for rapid response monitoring and control, and at supervisory level, applying big data analysis for decision-making, planning and optimization. Some experiments have been performed in the context of an electric micro grid where agents were able to perform distributed data analysis to predict the renewable energy production.info:eu-repo/semantics/publishedVersio

Findings from a pilot randomized trial of spinal decompression alone or spinal decompression plus instrumented fusion

Aims: Symptomatic spinal stenosis is a very common problem, and decompression surgery has been shown to be superior to nonoperative treatment in selected patient groups. However, performing an instrumented fusion in addition to decompression may avoid revision and improve outcomes. The aim of the SpInOuT feasibility study was to establish whether a definitive randomized controlled trial (RCT) that accounted for the spectrum of pathology contributing to spinal stenosis, including pelvic incidence-lumbar lordosis (PI-LL) mismatch and mobile spondylolisthesis, could be conducted. Methods: As part of the SpInOuT-F study, a pilot randomized trial was carried out across five NHS hospitals. Patients were randomized to either spinal decompression alone or spinal decompression plus instrumented fusion. Patient-reported outcome measures were collected at baseline and three months. The intended sample size was 60 patients. Results: Of the 90 patients screened, 77 passed the initial screening criteria. A total of 27 patients had a PI-LL mismatch and 23 had a dynamic spondylolisthesis. Following secondary inclusion and exclusion criteria, 31 patients were eligible for the study. Six patients were randomized and one underwent surgery during the study period. Given the low number of patients recruited and randomized, it was not possible to assess completion rates, quality of life, imaging, or health economic outcomes as intended. Conclusion: This study provides a unique insight into the prevalence of dynamic spondylolisthesis and PI-LL mismatch in patients with symptomatic spinal stenosis, and demonstrates that there is a need for a definitive RCT which stratifies for these groups in order to inform surgical decision-making. Nonetheless a definitive study would need further refinement in design and implementation in order to be feasible

A Tale of Two Current Sheets

I outline a new model of particle acceleration in the current sheet separating the closed from the open field lines in the force-free model of pulsar magnetospheres, based on reconnection at the light cylinder and "auroral" acceleration occurring in the return current channel that connects the light cylinder to the neutron star surface. I discuss recent studies of Pulsar Wind Nebulae, which find that pair outflow rates in excess of those predicted by existing theories of pair creation occur, and use those results to point out that dissipation of the magnetic field in a pulsar's wind upstream of the termination shock is restored to life as a viable model for the solution of the "$\sigma$" problem as a consequence of the lower wind 4-velocity implied by the larger mass loading.Comment: 17 pages, 6 figures, Invited Review, Proceedings of the "ICREA Workshop on The High-Energy Emission from Pulsars and their Systems", Sant Cugat, Spain, April 12-16, 201

California Current seascape influences juvenile salmon foraging ecology at multiple scales

Juvenile salmon Oncorhynchus spp. experience variable mortality rates during their first few months in the ocean, and high growth during this period is critical to minimize size selective predation. Examining links between the physical environment and foraging ecology is important to understand mechanisms that drive growth. These mechanisms are complex and include interactions among the physical environment, forage availability, bioenergetics, and salmon foraging behavior. Our objectives were to explore how seascape features (biological and physical) influence juvenile Chinook salmon O. tshawytscha foraging at annual and feedingevent scales in the California Current Ecosystem. We demonstrate that forage abundance was the most influential determinant of mean salmon stomach fullness at the annual scale, while at the feeding-event scale, fullness increased with greater cumulative upwelling during the 10 d prior and at closer distances to thermal fronts. Upwelling promotes nutrient enrichment and productivity, while fronts concentrate organisms, likely resulting in available prey to salmon and increased stomach fullness. Salmon were also more likely to consume krill when there was high prior upwelling,andswitchedtonon-krillinvertebrates(i.e.amphipods,decapods,copepods)inweaker upwelling conditions. As salmon size increased from 72−250 mm, salmon were more likely to consume fish, equal amounts of krill, and fewer non-krill invertebrates. Broad seascape processes determined overall prey availability and fullness in a given year, while fine- and meso-scale processes influenced local accessibility of prey to individual salmon. Therefore, processes occurring at multiple scales will influence how marine organisms respond to changing environment

Age- and Sex-Specific Mortality Patterns in an Emerging Wildlife Epidemic: The Phocine Distemper in European Harbour Seals

Analyses of the dynamics of diseases in wild populations typically assume all individuals to be identical. However, profound effects on the long-term impact on the host population can be expected if the disease has age and sex dependent dynamics. The Phocine Distemper Virus (PDV) caused two mass mortalities in European harbour seals in 1988 and in 2002. We show the mortality patterns were highly age specific on both occasions, where young of the year and adult (>4 yrs) animals suffered extremely high mortality, and sub-adult seals (1–3 yrs) of both sexes experienced low mortality. Consequently, genetic differences cannot have played a main role explaining why some seals survived and some did not in the study region, since parents had higher mortality levels than their progeny. Furthermore, there was a conspicuous absence of animals older than 14 years among the victims in 2002, which strongly indicates that the survivors from the previous disease outbreak in 1988 had acquired and maintained immunity to PDV. These specific mortality patterns imply that contact rates and susceptibility to the disease are strongly age and sex dependent variables, underlining the need for structured epidemic models for wildlife diseases. Detailed data can thus provide crucial information about a number of vital parameters such as functional herd immunity. One of many future challenges in understanding the epidemiology of the PDV and other wildlife diseases is to reveal how immune system responses differ among animals in different stages during their life cycle. The influence of such underlying mechanisms may also explain the limited evidence for abrupt disease thresholds in wild populations

"Am iz kwiin" (I'm his queen): Combining interpretative phenomenological analysis with a feminist approach to work with gems in a resource-constrained setting

This article focuses on working with gems using a feminist approach to interpretative phenomenological analysis (IPA) in a resource-constrained setting. The research explores the experiences of maternal disclosure of HIV to children of HIV positive mothers in Kingston, Jamaica. A feminist approach helps recognise power imbalances within research relationships and the women’s lived experiences. We present three “gems” which illuminate women’s lived experiences and explore how popularised representations of women’s sexuality and mothering influence disclosure discourses. We use emotion work as a conceptual resource to structure the women’s narratives and challenge existing policy discourses, which arguably represent disclosure within a binary, rationalist, decision-making framework. This article adds to global literature on maternal HIV disclosure and problematises policy discourses by bringing into relief the emotion work women engage in when deciding if and how to communicate their HIV status to their children. It adds to the body of research using IPA, particularly in resource-constrained settings where IPA has thus far had little application

State of the California current 2012-13: No such thing as an “average” year

This report reviews the state of the California Current System (CCS) between winter 2012 and spring 2013, and includes observations from Washington State to Baja California. During 2012, large-scale climate modes indicated the CCS remained in a cool, productive phase present since 2007. The upwelling season was delayed north of 42°N, but regions to the south, especially 33° to 36°N, experienced average to above average upwelling that persisted throughout the summer. Contrary to the indication of high production suggested by the climate indices, chlorophyll observed from surveys and remote sensing was below average along much of the coast. As well, some members of the forage assemblages along the coast experienced low abundances in 2012 surveys. Specifically, the concentrations of all lifestages observed directly or from egg densities of Pacific sardine, Sardinops sagax, and northern anchovy, Engraulis mordax, were less than previous years’ survey estimates. However, 2013 surveys and observations indicate an increase in abundance of northern anchovy. During winter 2011/2012, the increased presence of northern copepod species off northern California was consistent with stronger southward transport. Krill and small-fraction zooplankton abundances, where examined, were generally above average. North of 42°N, salps returned to typical abundances in 2012 after greater observed concentrations in 2010 and 2011. In contrast, salp abundance off central and southern California increased after a period of southward transport during winter 2011/2012. Reproductive success of piscivorous Brandt’s cormorant, Phalacrocorax penicillatus, was reduced while planktivorous Cassin’s auklet, Ptychoramphus aleuticus was elevated. Differences between the productivity of these two seabirds may be related to the available forage assemblage observed in the surveys. California sea lion pups from San Miguel Island were undernourished resulting in a pup mortality event perhaps in response to changes in forage availability. Limited biological data were available for spring 2013, but strong winter upwelling coastwide indicated an early spring transition, with the strong upwelling persisting into early summer