Gas signatures of Herbig Ae/Be disks probed with Herschel SPIRE spectroscopy

Herbig Ae/Be objects, like their lower mass counterparts T Tauri stars, are seen to form a stable circumstellar disk which is initially gas-rich and could ultimately form a planetary system. We present Herschel SPIRE 460-1540 GHz spectra of five targets out of a sample of 13 young disk sources, showing line detections mainly due to warm CO gas.Comment: to be published in proceedings of IAU symposium 299 (Victoria, BC, Canada, June 2013

Ages of young stars

Determining the sequence of events in the formation of stars and planetary systems and their time-scales is essential for understanding those processes, yet establishing ages is fundamentally difficult because we lack direct indicators. In this review we discuss the age challenge for young stars, specifically those less than ~100 Myr old. Most age determination methods that we discuss are primarily applicable to groups of stars but can be used to estimate the age of individual objects. A reliable age scale is established above 20 Myr from measurement of the Lithium Depletion Boundary (LDB) in young clusters, and consistency is shown between these ages and those from the upper main sequence and the main sequence turn-off -- if modest core convection and rotation is included in the models of higher-mass stars. Other available methods for age estimation include the kinematics of young groups, placing stars in Hertzsprung-Russell diagrams, pulsations and seismology, surface gravity measurement, rotation and activity, and lithium abundance. We review each of these methods and present known strengths and weaknesses. Below ~20 Myr, both model-dependent and observational uncertainties grow, the situation is confused by the possibility of age spreads, and no reliable absolute ages yet exist. The lack of absolute age calibration below 20 Myr should be borne in mind when considering the lifetimes of protostellar phases and circumstellar material.Comment: Accepted for publication as a chapter in Protostars and Planets VI, University of Arizona Press (2014), eds. H. Beuther, R. Klessen, C. Dullemond, Th. Hennin

Knowledge management across the environment-policy interface in China: What knowledge is exchanged, why, and how is this undertaken?

Global to local environmental policy-making is increasingly evidenced-based. Knowledge management (KM) is increasingly used by environmental scientists and policymakers, to deliver evidence-based policy and practice. There is thus an urgent need to identify whether and how knowledge is exchanged between knowledge producers and users in environmental science fields. Here we apply an assessment framework developed in social medicine to identify what forms of environmental knowledge are exchanged, and why and how they are exchanged. We focussed on China, as international research to better manage Chinese ecosystem services is rapidly-increasing, yet, how to best integrate this into political decision-making and the public realm remains a challenge. How KM is practiced in China is unknown. We addressed this through: 1) a systematic analysis of published KM research in China compared to global trends; 2) evaluating KM for environmental policy and management in China; 3) quantitative surveys of Chinese (n = 72) and British (n = 16) scientists researching Chinese environmental problems. The systematic literature review of two databases identified two key findings. One, of 291 papers that considered KM there were no papers in the environmental sector examining the science-policy-practice interface in China. Two, only 13 of 423 potentially relevant papers explicitly examined KM for environmental topics, notably for agriculture and information exchange (the 'What?'). Most papers reported a one-way interaction between scientists and users (the 'How?'), used to change practice (the 'Why?'). Our survey showed significantly-less awareness and use of two-way knowledge exchange (KE) methods by Chinese scientists. The paucity of documented KM research and limited evidence for two-way interaction show KE at the environmental science-policy-practice interface in China is limited. Promotion of KE practice may benefit environmental policy-making in China. We have also shown that conceptual frameworks for mapping and assessing KE practice from social medicine can be usefully adapted for examining environmental science – policy interfaces

Historical Analysis of Submerged Aquatic Vegetation (SAV) in the Potomac River and Analysis of Bay-wide SAV Data to Establish a New Acreage Goal : Final Report

Throughout most regions of the Chesapeake Bay and its tributaries both direct and anecdotal evidence has indicated that large-scale declines of submerged aquatic vegetation (SAV) occurred in the late 1960s and early 1970s (Orth and Moore 1983). These declines have been related to increasing amounts of non-point inputs of nutrients and sediments in the bay system resulting from development of the bay’s shorelines and watershed (Twilley et al. 1985). Currently there are approximately 89,659 acres of SAV in Chesapeake Bay (Orth et al. 2003). Although it has been estimated that this is approximately 15% of the bay’s historical SAV distribution, most comprehensive analyses have been based on 1971 or later aerial photography and the distributions of SAV prior to this time in many regions are not well known. SAV is a highly valuable resource and its presence serves as an important indicator of local water quality conditions (Dennison et al. 1993). SAV growth and survival can be decreased by high levels of turbidity and nutrient enrichment. Because SAV beds are non-motile, their presence serves as an integrating measure of variable water quality conditions in local areas (Moore et al. 1996). Because of the direct relationships between SAV and water quality, trends in the distribution and abundance of SAV over time are also very useful in understanding trends in water quality. Review of photographic evidence from a number of sites dating back to 1937 suggests that SAV, once abundant throughout the Chesapeake Bay system, have declined from historical levels and therefore water quality conditions may have similarly deteriorated (Orth and Moore 1983)

Naturally processed measles virus peptide eluted from class II HLA-DRB1*03 recognized by T lymphocytes from human blood

AbstractThis is the first report of the direct identification of a HLA-DRB1*03 measles-derived peptide from measles virus infected EBV-transformed B cells. We purified HLA-DR3-peptide complexes from EBV-B cells infected with measles virus (Edmonston strain) and sequenced the HLA-DR3-peptides by mass spectrometry. A class II peptide, derived from a measles phosphoprotein, ASDVETAEGGEIHELLRLQ (P1, residues 179–197), exhibited the capacity to stimulate peripheral blood mononuclear cells to proliferate. Our data provides direct evidence that the antigenic peptide of measles virus was processed by antigen-presenting cells, presented in the context of HLA class II molecules, and was recognized by peripheral blood T cells from healthy individuals previously immunized with measles vaccine. The approach described herein provides a useful methodology for the future identification of HLA-presented pathogen-derived epitopes using mass spectrometry. The study of cell-mediated immune responses to the measles-derived peptide in immune persons should provide significant insight into the design and development of new vaccines

How does smallholder farming practice and environmental awareness vary across village communities in the karst terrain of southwest China?

Worldwide, karst terrain is highly sensitive to human activity due to extensive areas of thin soil and rapid water flow to groundwater. In the southwest China karst region, poor farming decisions can promote land degradation and reduce water quality with negative consequences for livelihoods in a region where farmers already suffer from the highest national poverty rates. Targeting management advice to farmers through knowledge exchange and decision support can help alleviate land use impacts on the karst environment but first requires baseline knowledge of how local farming communities understand and approach soil and water management. We used a catchment-wide survey (n = 312 individuals in seven villages) to investigate differences in environmental awareness, catchment understanding, and farming practices amongst farmers and community leaders in a typical karst catchment in southwest China. Age, gender and village of residence of farmers showed an association with the type of challenges perceived to be most serious. Access to labour, issues of water quantity and/or quality affecting irrigation, and fertiliser costs were recognised as being particularly problematic for the viability of farming. Sources of information used to learn about farming practices, the environment and fertiliser use were more diverse for younger (< 40 yr old) farmers and levels of training and acquired knowledge regarding land management practices varied significantly between villages in the catchment. The identification of significant associations between villages or sample demographics, and a variety of questions designed to understand farmer attitudes and their environmental awareness, provide clearer insight upon which knowledge exchange and training programmes can be co-designed with catchment stakeholders. This has the potential to lead to improved farming practices with co-benefits for farmers and the environment; helping sustain ecosystem services for impoverished communities in fragile karst ecosystems

Comparing biomechanical time series data across countermovement shrug loads

The effect of load on time-series data has yet to be investigated during weightlifting derivatives. This study compared the effect of load on the force–time and velocity–time curves during the countermovement shrug (CMS). Twenty-nine males performed the CMS at relative loads of 40 %, 60 %, 80 %, 100 %, 120 %, and 140 % one repetition maximum (1RM) power clean (PC). A force plate measured the vertical ground reaction force (VGRF), which was used to calculate the barbell-lifter system velocity. Time-series data were normalized to 100 % of the movement duration and assessed via statistical parametric mapping (SPM). SPM analysis showed greater negative velocity at heavier loads early in the unweighting phase (12–38 % of the movement), and greater positive velocity at lower loads during the last 16 % of the movement. Relative loads of 40 % 1RM PC maximised propulsion velocity, whilst 140 % 1RM maximized force. At higher loads, the braking and propulsive phases commence at an earlier percentage of the time-normalized movement, and the total absolute durations increase with load. It may be more appropriate to prescribe the CMS during a maximal strength mesocycle given the ability to use supramaximal loads. Future research should assess training at different loads on the effects of performance

Herschel SPIRE Fourier Transform Spectrometer: Calibration of its Bright-source Mode

The Fourier Transform Spectrometer (FTS) of the Spectral and Photometric Imaging REceiver (SPIRE) on board the ESA Herschel Space Observatory has two detector setting modes: (a) a nominal mode, which is optimized for observing moderately bright to faint astronomical targets, and (b) a bright-source mode recommended for sources significantly brighter than 500 Jy, within the SPIRE FTS bandwidth of 446.7-1544 GHz (or 194-671 microns in wavelength), which employs a reduced detector responsivity and out-of-phase analog signal amplifier/demodulator. We address in detail the calibration issues unique to the bright-source mode, describe the integration of the bright-mode data processing into the existing pipeline for the nominal mode, and show that the flux calibration accuracy of the bright-source mode is generally within 2% of that of the nominal mode, and that the bright-source mode is 3 to 4 times less sensitive than the nominal mode.Comment: 15 pages, 16 figures, accepted for publication in Experimental Astronom