Autonomous space processor for orbital debris

This work continues to develop advanced designs toward the ultimate goal of a GETAWAY SPECIAL to demonstrate economical removal of orbital debris utilizing local resources in orbit. The fundamental technical feasibility was demonstrated last year through theoretical calculations, quantitative computer animation, a solar focal point cutter, a robotic arm design and a subscale model. During this reporting period, several improvements are made in the solar cutter, such as auto track capabilities, better quality reflectors and a more versatile framework. The major advance has been in the design, fabrication and working demonstration of a ROBOTIC ARM that has several degrees of freedom. The functions were specifically tailored for the orbital debris handling. These advances are discussed here. Also a small fraction of the resources were allocated towards research in flame augmentation in SCRAMJETS for the NASP. Here, the fundamental advance was the attainment of Mach numbers up to 0.6 in the flame zone and a vastly improved injection system; the current work is expected to achieve supersonic combustion in the laboratory and an advanced monitoring system

Current-carrying cosmic string loops 3D simulation: towards a reduction of the vorton excess problem

The dynamical evolution of superconducting cosmic string loops with specific equations of state describing timelike and spacelike currents is studied numerically. This analysis extends previous work in two directions: first it shows results coming from a fully three dimensional simulation (as opposed to the two dimensional case already studied), and it now includes fermionic as well as bosonic currents. We confirm that in the case of bosonic currents, shocks are formed in the magnetic regime and kinks in the electric regime. For a loop endowed with a fermionic current with zero-mode carriers, we show that only kinks form along the string worldsheet, therefore making these loops slightly more stable against charge carrier radiation, the likely outcome of either shocks or kinks. All these combined effects tend to reduce the number density of stable loops and contribute to ease the vorton excess problem. As a bonus, these effects also may provide new ways of producing high energy cosmic rays.Comment: 11 pages, RevTeX 4 format, 8 figures, submitted to PR

Anthropics and Myopics: Conditional Probabilities and the Cosmological Constant

We re-examine claims that anthropic arguments provide an explanation for the observed smallness of the cosmological constant, and argue that correlations between the cosmological constant value and the existence of life can be demonstrated only under restrictive assumptions. Causal effects are more subtle to uncover.Comment: revised to PRL format, additional references and discussion to related work revise

Monitoring Seagrass within the Reef 2050 Integrated Monitoring and Reporting Program: final report of the Seagrass Expert Group

Seagrass is widely distributed throughout the Great Barrier Reef (the Reef), with a documented 35,000 square kilometres and a potential habitat area of 228,300 square kilometres. Seagrass meadows occur in many different environmental conditions, both within and beyond the impact of flood plumes, and are common in areas of high anthropogenic activity, such as ports and areas adjacent to urban centres. Many processes and services that maintain the exceptional values of the Reef occur in seagrass meadows. To provide the services that support these values seagrass habitats include a range of species, growth forms and benthic landscapes, that respond to pressures in different ways. In many cases seagrasses also modify their environments to improve environmental conditions on the Reef. Seagrasses vary spatially and temporally in their distribution and abundance across the Reef, occurring in different water quality types (estuaries, coastal, reefal and offshore) and at different water depths (intertidal, shallow subtidal, deep water). The diversity of potential seagrass habitats is one reason they support so many of the environmental services and values of the Great Barrier Reef World Heritage Area (World Heritage Area), including: habitat for crabs, prawns and fish –– supporting recreational and commercial fishing; primary food resource for species of conservation significance (dugong, green turtles, migratory shore birds); shoreline stabilisation by binding sediment to slow erosion; water clarity improvement, by promoting the settlement of fine particulate matter; and providing a natural carbon sink. To deliver the seagrass components of the knowledge system required to deliver Reef 2050 Long-Term Sustainability Plan (Reef 2050 Plan) reporting and other management activities, there will need to be modifications and enhancements made to the current seagrass monitoring programs. The Drivers, Pressures, State, Impact, Response (DPSIR) framework was used to facilitate the identification of linkages between the pressures on seagrass, state of the seagrass, the impact a decline in seagrass would have on community values, and the responses management agencies can take to mitigate loss of values. We have also defined twelve seagrass habitat types that occur on the Reef, identified by a matrix of water body type and water depth. The seagrasses occurring in each habitat are exposed to different pressures and require different management actions (responses) to protect and enhance the values of the community and Reef ecosystems. The proposed monitoring program has three spatial and temporal scales, with each scale providing different information (knowledge) to support resilience-based management of the Reef. 1. Habitat assessment: will occur across the Reef at all sites where seagrass has a potential of occurring. It will determine seagrass abundance, species composition and spatial extent of each habitat type within the World Heritage Area. This scale will be focused on supporting future outlook reports, but will also provide information for operational and strategic management and contribute towards other reports. 2. Health assessment: will take place at representative regional sites, for each habitat type. These sites will provide managers with annual and seasonal trends in seagrass condition and resilience at a regional scale for each habitat. This scale will provide higher temporal detail (i.e. at least annually) of seagrass condition and resilience, supporting tactical, operational and strategic management applications. This scale will provide the majority of information for regional/catchment report cards and the assessment of management effectiveness at a catchment wide scale. It will also contribute important trends in condition and resilience to Outlook reports and other communication products with more frequent reporting. 3. Process monitoring: will take place at the fewest number of sites, nested within habitat and health assessment sites. Due to the time-consuming and complex nature of these measurements the sampling sites will be chosen to focus on priority knowledge gaps. This scale will provide managers with information on cause-and-effect relationships and linkages between different aspects of the Reef’s processes and ecosystems. This scale will include measures of seagrass resilience (for example, feedback loops, recovery time after disturbance, history of disturbance and thresholds for exposure to pressures). The attributes measured at these sites will also provide confidence to managers regarding the impact a change in seagrass condition is likely to have on other values of the Reef (for example, fish, megafauna, coral, Indigenous heritage, and human dimensions). To ensure that future seagrass monitoring delivers the information required to report on the Reef 2050 Plan and meets the other knowledge requirements of managers, a spatially balanced random sampling design needs to be implemented on the Reef. Existing monitoring programs can and should be integrated into this design. However, current seagrass monitoring programs do not provide a balanced assessment of seagrass condition across the entire Reef, hence are not suitable to meet the Reef 2050 Plan reporting requirements and many other management information needs. Existing sites within current monitoring are focused on habitat types that are intertidal and shallow sub-tidal and lie close to the coast. These habitats have been previously selected because they face high levels of cumulative anthropogenic risk and therefore have higher levels of management demand for information. The current sites are likely to decline more rapidly, in response to catchment run-off and other anthropogenic pressures, than the average for seagrass meadows across the entire Reef. They also have a greater potential to show improvements from Reef catchment management actions that reduce pollution associated with run-off. This report sets out the framework for a recommended new seagrass monitoring program, highlighting the substantial improvements in knowledge and confidence this new program will deliver, and provides a scope for the statistical design work required to support implementation of this program

Modeling the impact of floating oyster (Crassostrea virginica) aquaculture on sediment−water nutrient and oxygen fluxes

Bivalve aquaculture relies on naturally occurring phytoplankton, zooplankton, and detritus as food sources, thereby avoiding external nutrient inputs that are commonly associated with finfish aquaculture. High filtration rates and concentrated bivalve biomass within aquacul- ture operations, however, result in intense biodeposition of particulate organic matter (POM) on surrounding sediments, with potential adverse environmental impacts. Estimating the net deposi- tional flux is difficult in shallow waters due to methodological constraints and dynamic processes such as resuspension and advection. In this study, we combined sediment trap deployments with simulations from a mechanistic sediment flux model to estimate seasonal POM deposition, resus- pension, and processing within sediments in the vicinity of an eastern oyster Crassostrea virginica farm in the Choptank River, Maryland, USA. The model is the stand-alone version of a 2-layer sediment flux model currently implemented within larger models for understanding ecosystem responses to nutrient management. Modeled sediment−water fluxes were compared to observed denitrification rates and nitrite + nitrate (NO2 −+NO3 −), phosphate (PO4 3−) and dissolved O2 fluxes. Model-derived estimates of POM deposition, which represent POM incorporated and processed within the sediment, comprised a small fraction of the material collected in sediment traps. These results highlight the roles of biodeposit resuspension and transport in effectively removing oyster biodeposits away from this particular farm, resulting in a highly diminished local environmental impact. This study highlights the value of sediment models as a practical tool for computing inte- grated measures of nitrogen cycling as a function of seasonal dynamics in the vicinity of aquaculture operations

‘Ethnic group’, the state and the politics of representation

The assertion, even if only by implication, that ‘ethnic group’ categories represent ‘real’ tangible entities, indeed identities, is commonplace not only in the realms of political and policy discourse but also amongst contemporary social scientists. This paper, following Brubaker (2002), questions this position in a number of key respects: of these three issues will dominate the discussion that follows. First, there is an interrogation of the proposition that those to whom the categories/labels refer constitute sociologically meaningful ‘groups’ as distinct from (mere) human collectivities. Secondly, there is the question of how these categories emerge, i.e. exactly what series of events, negotiations and contestations lie behind their construction and social acceptance. Thirdly, and as a corollary to the latter point, we explore the process of reification that leads to these categories being seen to represent ‘real things in the world’ (ibid.)

Haploinsufficiency of the schizophrenia and autism risk gene Cyfip1 causes abnormal postnatal hippocampal neurogenesis through microglial and Arp2/3 mediated actin dependent mechanisms

Genetic risk factors can significantly increase chances of developing psychiatric disorders, but the underlying biological processes through which this risk is effected remain largely unknown. Here we show that haploinsufficiency of Cyfip1, a candidate risk gene present in the pathogenic 15q11.2(BP1–BP2) deletion may impact on psychopathology via abnormalities in cell survival and migration of newborn neurons during postnatal hippocampal neurogenesis. We demonstrate that haploinsufficiency of Cyfip1 leads to increased numbers of adult-born hippocampal neurons due to reduced apoptosis, without altering proliferation. We show this is due to a cell autonomous failure of microglia to induce apoptosis through the secretion of the appropriate factors, a previously undescribed mechanism. Furthermore, we show an abnormal migration of adult-born neurons due to altered Arp2/3 mediated actin dynamics. Together, our findings throw new light on how the genetic risk candidate Cyfip1 may influence the hippocampus, a brain region with strong evidence for involvement in psychopathology

Definitions, Criteria and Global Classification of Mast Cell Disorders with Special Reference to Mast Cell Activation Syndromes: A Consensus Proposal

Activation of tissue mast cells (MCs) and their abnormal growth and accumulation in various organs are typically found in primary MC disorders also referred to as mastocytosis. However, increasing numbers of patients are now being informed that their clinical findings are due to MC activation (MCA) that is neither associated with mastocytosis nor with a defined allergic or inflammatory reaction. In other patients with MCA, MCs appear to be clonal cells, but criteria for diagnosing mastocytosis are not met. A working conference was organized in 2010 with the aim to define criteria for diagnosing MCA and related disorders, and to propose a global unifying classification of all MC disorders and pathologic MC reactions. This classification includes three types of `MCA syndromes' (MCASs), namely primary MCAS, secondary MCAS and idiopathic MCAS. MCA is now defined by robust and generally applicable criteria, including (1) typical clinical symptoms, (2) a substantial transient increase in serum total tryptase level or an increase in other MC-derived mediators, such as histamine or prostaglandin D 2, or their urinary metabolites, and (3) a response of clinical symptoms to agents that attenuate the production or activities of MC mediators. These criteria should assist in the identification and diagnosis of patients with MCAS, and in avoiding misdiagnoses or overinterpretation of clinical symptoms in daily practice. Moreover, the MCAS concept should stimulate research in order to identify and exploit new molecular mechanisms and therapeutic targets. Copyright (C) 2011 S. Karger AG, Base

Enhanced Expression of Janus Kinase–Signal Transducer and Activator of Transcription Pathway Members in Human Diabetic Nephropathy

OBJECTIVE—Glomerular mesangial expansion and podocyte loss are important early features of diabetic nephropathy, whereas tubulointerstitial injury and fibrosis are critical for progression of diabetic nephropathy to kidney failure. Therefore, we analyzed the expression of genes in glomeruli and tubulointerstitium in kidney biopsies from diabetic nephropathy patients to identify pathways that may be activated in humans but not in murine models of diabetic nephropathy that fail to progress to glomerulosclerosis, tubulointerstitial fibrosis, and kidney failure