92 research outputs found

    Establishing a Multibeam Sonar Evaluation Test Bed near Sidney, British Columbia

    Get PDF
    The Canadian Hydrographic Service (CHS), Naval Oceanographic Office (NAVOCEANO) and the Ocean Mapping Group of the University of New Brunswick (OMG) collaborated on establishing a multibeam sonar test bed in the vicinity of the Institute of Ocean Sciences in Sidney, British Columbia Canada. This paper describes the purpose of the sonar evaluation test bed, the trials and tribulations of two foreign governments collaborating on projects of mutual interest, the evaluation areas and their characteristics for sonar testing, and sample results of sonar evaluations using this test bed. Some target detection comparisons of several systems over a range of artificial sonar targets will also be given

    Distribución y estado del Jacamar Galbula ruficauda (Aves: Galbulidae) en Paraguay

    Get PDF
    Rufous-tailed Jacamar Galbula ruficauda is known from few records in Paraguay, all during the last 20 years. The species has been recorded in the northern Chaco and Paraguayan Pantanal, with all confirmed records from Alto Paraguay department. Here we summarise all reports and localities of the species in Paraguay to date. The species is categorized as Data Deficient at the national level, but may be more widely distributed than is currently recognised.Galbula ruficauda es una especie que cuenta con pocos registros a lo largo de 20 años en Paraguay. La especie ha sido observada en la zona norte del Chaco y Pantanal paraguayo, departamento Alto Paraguay. En este trabajo reportamos los registros y localidades de ocurrencia de la especie en el país. Actualmente se encuentra en la categoría de Datos Insuficientes a nivel nacional, aunque puede ser que su distribución sea más amplia

    Plumage development and molt in long-tailed manakins (chiroxiphia linearis): variation according to sex and age

    Get PDF
    Lek-mating Long-tailed Manakins (Chiroxiphia linearis) exhibit an unusual pattern of delayed plumage maturation. Each year, males progress through a series of predefinitive plumages before attaining definitive plumage in their fifth calendar year. Females also exhibit variation in plumage coloration, with some females displaying male-like plumage characteristics. Using data from mist-net captures in northwest Costa Rica (n = 1,315) and museum specimens from throughout the range of Long-tailed Manakins (n = 585), we documented the plumage sequence progression of males, explored variation in female plumage, and described the timing of molt in this species. Males progressed through a series of age-specific predefinitive plumages, which enabled the accurate aging of predefinitive-plumaged males in the field; this predefinitive plumage sequence is the basis for age-related status-signaling in these males. Females tended to acquire red coloration in the crown as they aged. However, colorful plumage in females may be a byproduct of selection on bright male plumage. Females exhibited an early peak of molt activity from February to April, little molt from May through July, and a second, more pronounced peak of molt activity in October. By contrast, males in older predefinitive-plumage stages and males in definitive plumage exhibited comparable unimodal distributions in molt activity beginning in June and peaking between July and October. Our data are consistent with selective pressure to avoid the costs of molt-breeding overlap in females and older males. Our findings have important implications for social organization and signaling in Long- tailed Manakins, and for the evolution of delayed plumage maturation in birds. Desarrollo del Plumaje y Muda en Chiroxiphia linearis: Variación de Acuerdo al Sexo y la Eda

    Presencia del Estornino Pinto, Sturnus vulgaris Linnaeus, 1758 (Aves, Passeriformes, Sturnidae) en el Paraguay

    Get PDF
    Reportamos los primeros registros del Estornino Pinto, Sturnus vulgaris Linnaeus, 1758 en Paraguay, en base a observaciones realizadas en la última década en Asunción y el departamento de San Pedro

    Constraining the Carbon Budget of Peat Ecosystems: Application of Stoichiometry and Enthalpy Balances

    Get PDF
    We consider how the stoichiometry and energy content of organic matter reservoirs and fluxes through and from a peatland enable the fluxes and storage of carbon within a peatland to be constrained. We include the elemental composition of the above- and below-ground biomass, litter, the peat profile, and the dissolved and particulate organic matter within a blanket bog in northern England for which the C budget has previously been measured. The study shows, based only on the elemental composition, and calculation of oxidation and energy contents, that: (a) Dissolved organic carbon (DOC) in first-order streams is significantly more oxidized than in peat pore water but that there was no significant difference in organic carbon oxidation state down the peat profile; (b) The occurrence and speciation of N uptake and release in the peatland with N used and recycled can be predicted; (c) The relatively high oxidation state of DOC in stream water acts as an endpoint for peat-forming reactions; (d) Methanogenesis does not result in deep peat formation as its requirement for energy consumes too much organic matter to form residual peat at depth; (e) Sulfate reduction does occur during the formation of deep peat; (f) Organic matter elemental composition could be constrained to within three bounding equations though the proportions of carbon species could not be specified. (g) The formation of deep peat in this catchment could only be achieved if the dissolved organic matter (DOM) in the peat pore water is the dominant electron acceptor and energy source in the production of residual organic matter; however, it is unclear as to the flux of DOM up or down the peat profile

    Informed debate on the use of fire for peatland management means acknowledging the complexity of socio-ecological systems

    Get PDF
    The effects of fire and its use on European peatlands and heaths are the focus of considerable research and debate due to the important services these ecosystems provide and the threats they face from climatic and land-use change. Whilst in some countries ecologists are actively promoting the restoration of historic fire management regimes, in the UK the debate has become increasingly acrimonious. Positions seem entrenched between continuing the intensive form of management associated with grouse moors or ceasing burning and seeking to eliminate fire altogether. In a recent paper we argued that participants’ positions appeared influenced by political and philosophical beliefs associated with, for example, private land-ownership, hunting, and associated conservation conflicts such as raptor persecution. We also suggested there was inadequate engagement with key concepts and evidence from fire and peatland ecology. We argued that management debates should aim to be inclusive and evidence-based, and to understand the benefits and costs of different fire regimes. In a strongly-worded critique of our paper, George Monbiot (author of “Feral: Searching for Enchantment on the Frontiers of Rewilding”) suggested we: i) framed our research question too narrowly; ii) made the implicit assumption that moorlands were the “right” ecosystem for the UK countryside; and iii) failed to adequately engage with arguments put forward for cessation of managed burning. Here we critically examine each of these issues to provide further insight into how adaptive, participatory land-management could develop. We argue that a productive debate must acknowledge that complex trade-offs are inevitable during ecological management. Choosing the “right” ecosystem is difficult, especially in a landscape with a long history of human influence, and the answer depends on the values and ecosystem services we prioritize. Natural resource management decisions will be improved if based on an understanding and valuation of the multiple scales and levels of organization at which ecological diversity exists, the role of disturbance in controlling ecosystem composition and function, and the need for participatory action

    Ramucirumab for Treating Advanced Gastric Cancer or Gastro-Oesophageal Junction Adenocarcinoma Previously Treated with Chemotherapy

    Get PDF
    The National Institute for Health and Care Excellence (NICE) invited the company that manufactures ramucirumab (Cyramza®, Eli Lilly and Company) to submit evidence of the clinical and cost effectiveness of the drug administered alone (monotherapy) or with paclitaxel (combination therapy) for treating adults with advanced gastric cancer or gastro-oesophageal junction (GC/GOJ) adenocarcinoma that were previously treated with chemotherapy, as part of the Institute’s single technology appraisal (STA) process. Kleijnen Systematic Reviews Ltd (KSR), in collaboration with Erasmus University Rotterdam, was commissioned to act as the Evidence Review Group (ERG). This paper describes the company’s submission, the ERG review, and NICE’s subsequent decisions. Clinical effectiveness evidence for ramucirumab monotherapy (RAM), compared with best supportive care (BSC), was based on data from the REGARD trial. Clinical effectiveness evidence for ramucirumab combination therapy (RAM + PAC), compared with paclitaxel monotherapy (PAC), was based on data from the RAINBOW trial. In addition, the company undertook a network meta-analysis (NMA) to compare RAM + PAC with BSC and docetaxel. Cost-ef

    Mapping cumulative noise from shipping to inform marine spatial planning

    Get PDF
    Including ocean noise in marine spatial planning requires predictions of noise levels on large spatiotemporal scales. Based on a simple sound transmission model and ship track data (Automatic Identification System, AIS), cumulative underwater acoustic energy from shipping was mapped throughout 2008 in the west Canadian Exclusive Economic Zone, showing high noise levels in critical habitats for endangered resident killer whales, exceeding limits of “good conservation status” under the EU Marine Strategy Framework Directive. Error analysis proved that rough calculations of noise occurrence and propagation can form a basis for management processes, because spending resources on unnecessary detail is wasteful and delays remedial action

    The role of fire in UK peatland and moorland management: the need for informed, unbiased debate

    Get PDF
    Fire has been used for centuries to generate and manage some of the UK's cultural landscapes. Despite its complex role in the ecology of UK peatlands and moorlands, there has been a trend of simplifying the narrative around burning to present it as an only ecologically damaging practice. That fire modifies peatland characteristics at a range of scales is clearly understood. Whether these changes are perceived as positive or negative depends upon how trade-offs are made between ecosystem services and the spatial and temporal scales of concern. Here we explore the complex interactions and trade-offs in peatland fire management, evaluating the benefits and costs of managed fire as they are currently understood. We highlight the need for (i) distinguishing between the impacts of fires occurring with differing severity and frequency, and (ii) improved characterization of ecosystem health that incorporates the response and recovery of peatlands to fire. We also explore how recent research has been contextualized within both scientific publications and the wider media and how this can influence non-specialist perceptions. We emphasize the need for an informed, unbiased debate on fire as an ecological management tool that is separated from other aspects of moorland management and from political and economic opinions
    corecore