498 research outputs found
Applying the natural capital approach to decision making for the marine environment
The aspirations for natural capital and ecosystem service approaches to support environmental decision-making have not been fully realised in terms of their actual application in policy and management contexts. Application of the natural capital approach requires a range of methods, which as yet have not been fully tested in the context of decision making for the marine environment. It is unlikely that existing methodologies, which were developed for terrestrial systems and are based on land cover assessment approaches, will ever be feasible in the marine context at the national scale. Land cover approaches are also fundamentally insufficient for the marine environment because they do not take account of the water column, the significant interconnections between spatially disparate components, or the highly dynamic nature of the marine ecosystem, for example the high spatial mobility of many species. Data gaps have been a significant impediment to progress, so alternative methods that use proxies for quality information as well as the opportunities for remote sensing should be explored further. Greater effort to develop methodologies specifically for the marine environment is required, which should be interdisciplinary and cross-sectoral, coherent across policy areas, and applicable across a range of contexts
Flow and rent-based opportunity costs of water ecosystem service provision in a complex farming system
Unsustainable land uses present many challenges for securing ecosystem service provision. It is also difficult to estimate the cost of a transition to more sustainable land-management practices for individual landholders. The main cost to landholders is the opportunity costs, the income foregone when changing land use for continued or enhanced ecosystem service provision. Thus accurate estimation of opportunity costs and understanding their distribution are crucial starting points for determining the economic viability and design of any payment for ecosystem services (PES) scheme. We compare two opportunity cost approaches and examine the distribution of these costs for improving drinking water quality in a complex farming system in a Honduran forest catchment. Data for both approaches was collected through a survey applied to upstream catchment landholders. Our results indicate that the direct flow approach and the proxy rent approach provide comparable and consistent opportunity cost estimates. The mean net flow return ha-1 was US2 million per annum for water conservation, but a revised estimate comes to US$257,057 per annum. Opportunity costs were found to vary according to differences in land use and landholder characteristics. High value cash crops upholding the local economy, such as coffee, entail much higher opportunity costs than for example cattle grazing. These results suggest that discriminate PES payments, that vary according to opportunity costs and thus discriminate between land uses and landholders, are essential. Water quality at our case study site could be managed sustainably by a scheme focusing on high-impact land uses with lower opportunity costs and closer to water sources
Towards automated composition of convergent services: a survey
A convergent service is defined as a service that exploits the convergence of communication networks and at the same time takes advantage of features of the Web. Nowadays, building up a convergent service is not trivial, because although there are significant approaches that aim to automate the service composition at different levels in the Web and Telecom domains, selecting the most appropriate approach for specific case studies is complex due to the big amount of involved information and the lack of technical considerations. Thus, in this paper, we identify the relevant phases for convergent service composition and explore the existing approaches and their associated technologies for automating each phase. For each technology, the maturity and results are analysed, as well as the elements that must be considered prior to their application in real scenarios. Furthermore, we provide research directions related to the convergent service composition phases
Disruption of marine habitats by artificial light at night from global coastal megacities
Half of globally significant megacities are situated near the coast, exposing urban marine ecosystems to multiple stressors such as waste-water discharge containing a host of organic and inorganic pollutants, air and noise pollution. In addition to these well recognized sources, artificial light at night (ALAN) pollution is inseparable from cities but poorly quantified in marine ecosystems to date. We have developed a time- and wavelength-resolving hydrological optical model that includes solar (daylight and twilight components), lunar and ALAN source terms and propagates these spectrally through a tidally varying water column using Beer’s Law. Our model shows that for 8 globally distributed cities surface ALAN dosages are up to a factor of 6 greater than moonlight, as ALAN intensities vary little throughout the night, over monthly or seasonal cycles. Moonlight only exceeds ALAN irradiances over the ±3-day period around full moon, and particularly during the brightest moons (mid-latitude winter, at zenith). Unlike the relatively stable surface ALAN, underwater ALAN varies spectrally and in magnitude throughout the night due to tidal cycles. The extent of ALAN in-water attenuation is location-specific, driven by the season, tidal range and cycle, and water clarity. This work highlights that marine ALAN ecosystem pollution is a particularly acute global change issue near some of the largest cities in the world
Freshly Formed Dust in the Cassiopeia A Supernova Remnant as Revealed by the Spitzer Space Telescope
We performed Spitzer Infrared Spectrograph mapping observations covering
nearly the entire extent of the Cassiopeia A supernova remnant (SNR), producing
mid-infrared (5.5-35 micron) spectra every 5-10". Gas lines of Ar, Ne, O, Si, S
and Fe, and dust continua were strong for most positions. We identify three
distinct ejecta dust populations based on their continuum shapes. The dominant
dust continuum shape exhibits a strong peak at 21 micron. A line-free map of 21
micron-peak dust made from the 19-23 micron range closely resembles the [Ar
II], [O IV], and [Ne II] ejecta-line maps implying that dust is freshly formed
in the ejecta. Spectral fitting implies the presence of SiO2, Mg
protosilicates, and FeO grains in these regions. The second dust type exhibits
a rising continuum up to 21 micron and then flattens thereafter. This ``weak 21
micron'' dust is likely composed of Al2O3 and C grains. The third dust
continuum shape is featureless with a gently rising spectrum and is likely
composed of MgSiO3 and either Al2O3 or Fe grains. Using the least massive
composition for each of the three dust classes yields a total mass of 0.02
Msun. Using the most-massive composition yields a total mass of 0.054 Msun. The
primary uncertainty in the total dust mass stems from the selection of the dust
composition necessary for fitting the featureless dust as well as 70 micron
flux. The freshly formed dust mass derived from Cas A is sufficient from SNe to
explain the lower limit on the dust masses in high redshift galaxies.Comment: 8 figures: Accepted for the publication in Ap
Disruption of marine habitats by artificial light at night from global coastal megacities
Half of globally significant megacities are situated near the coast, exposing urban marine ecosystems to multiple stressors such as waste-water discharge containing a host of organic and inorganic pollutants, air and noise pollution. In addition to these well recognized sources, artificial light at night (ALAN) pollution is inseparable from cities but poorly quantified in marine ecosystems to date. We have developed a time- and wavelength-resolving hydrological optical model that includes solar (daylight and twilight components), lunar and ALAN source terms and propagates these spectrally through a tidally varying water column using Beer’s Law. Our model shows that for 8 globally distributed cities surface ALAN dosages are up to a factor of 6 greater than moonlight, as ALAN intensities vary little throughout the night, over monthly or seasonal cycles.
Moonlight only exceeds ALAN irradiances over the ±3-day period around full moon, and particularly during the
brightest moons (mid-latitude winter, at zenith). Unlike the relatively stable surface ALAN, underwater ALAN varies spectrally and in magnitude throughout the night due to tidal cycles. The extent of ALAN in-water attenuation is location-specific, driven by the season, tidal range and cycle, and water clarity. This work highlights that marine ALAN ecosystem pollution is a particularly acute global change issue near some of the largest cities in the world
Gray platelet syndrome: proinflammatory megakaryocytes and α-granule loss cause myelofibrosis and confer metastasis resistance in mice.
NBEAL2 encodes a multidomain scaffolding protein with a putative role in granule ontogeny in human platelets. Mutations in NBEAL2 underlie gray platelet syndrome (GPS), a rare inherited bleeding disorder characterized by a lack of α-granules within blood platelets and progressive bone marrow fibrosis. We present here a novel Nbeal2(-/-) murine model of GPS and demonstrate that the lack of α-granules is due to their loss from platelets/mature megakaryocytes (MKs), and not by initial impaired formation. We show that the lack of Nbeal2 confers a proinflammatory phenotype to the bone marrow MKs, which in combination with the loss of proteins from α-granules drives the development of bone marrow fibrosis. In addition, we demonstrate that α-granule deficiency impairs platelet function beyond their purely hemostatic role and that Nbeal2 deficiency has a protective effect against cancer metastasis.This work was funded by the British Heart
Foundation to CG (FS09/039) and WHO and AR (RG/09/12/28096); NHSBT to CB and HM;
Wellcome Trust (WT098051) to ZM, ELC, JE, HWJ and AOS.This is the accepted manuscript. The final published version is available from Blood at http://www.bloodjournal.org/content/early/2014/09/25/blood-2014-04-566760
Spitzer IRAC Images and Sample Spectra of Cassiopeia A's Explosion
We present Spitzer IRAC images, along with representative 5.27 to 38.5 micron
IRS spectra of the Cassiopeia A supernova remnant. We find that various IRAC
channels are each most sensitive to a different spectral and physical
component. Channel 1 (3.6 micron) matches radio synchrotron images. Where
Channel 1 is strong with respect to the other channels, the longer-wavelength
spectra show a broad continuum gently peaking around 26 micron, with weak or no
lines. We suggest that this is due to un-enriched progenitor circumstellar dust
behind the outer shock, processed by shock photons and electrons. Where Channel
4 (8 micron) is bright relative to the other IRAC channels, the long-wavelength
spectra show a strong, 2-3 micron-wide peak at 21 micron, likely due to
silicates and proto-silicates, as well as strong ionic lines of [Ar II], [Ar
III], [S IV] and [Ne II]. In these locations, the dust and ionic emission
originate from the explosion's O-burning layers. The regions where Channels 2
(4.5 micron) and 3 (5.6 micron) are strongest relative to Channel 4 show a
spectrum that rises gradually to 21 micron, and then flattens or rises more
slowly to longer wavelengths, along with higher ratios of [Ne II] to [Ar II].
Dust and ionic emission in these locations arise primarily from the C- and Ne-
burning layers. These findings are consistent with asymmetries in the explosion
producing variations in the velocity structure in different directions, but
preserving the nucleosynthetic layers. At each location, the dust and ionic
lines in the mid-infrared, and the hotter and more highly ionized optical and
X-ray emission are then dominated by the layer currently encountering the
reverse shock in that direction.Comment: 28 pages, 10 figures, accepted in to the Astrophysical Journal. For
full-resolution images, please see
http://webusers.astro.umn.edu/~jennis/iracpaper.html. Revised to correct an
error in reference
Variation in the intermittent buzzing songs of male medflies (diptera: tephritidae) associated with geography, mass-rearing, and courtship success
Varios aspectos de los patrones temporales de los sonidos del zumbido intermitente producido durante el cortejo pre-copulatĂłrio de los machos de la mosca del Mediterráneo variaron entre moscas silvestres de Costa Rica, Argentina y Hawaii, y entre moscas de sepas de crĂa masiva de Costa Rica, Argentina, Mexico y Hawaii. No se presentaron diferencias consistentes cuando se compararon las sepas de crĂa masiva en Costa Rica, Argentina y Hawaii con moscas silvestres de los sitios de origen. Los sonidos producidos durante cortejos que terminaron en cĂłpulas no difieron de los sonidos producidos durante cortejos que llevaron a montas que fracasaron en moscas de Costa Rica y Argentina. Pero en sepas de todos los sitios los zumbidos intermitentes que incluyeron pequeñas pausas tuvieron una mayor probabilidad de no terminar en un intento de monta. Los zumbidos intermitentes de las moscas de las crias masivas tuvieron una tendencia leve a interumpirse mas frecuentemente.Many aspects of the temporal pattern of sounds produced during the intermittent buzzing displays of pre-copulatory courtship by male medflies varied between wild flies from Costa Rica, Argentina, and Hawaii, and between mass-reared flies from Costa Rica, Argentina, Mexico, and Hawaii. There were no consistent differences when mass-reared strains were compared with the wild strains from the area where they originated in Costa Rica, Argentina and Hawaii. Buzzing sounds produced prior to successful mounting attempts did not differ consistently from those preceding unsuccessful mounts in flies from Costa Rica and Argentina. In strains from all sites, however, courtships in which buzzes were interrupted were more likely not to result in mounting of the female. There was a weak tendency for interruptions to be more common in mass-reared strains.Universidad de Costa Rica. Universidad de Buenos Aires. El Colegio de la Frontera Sur, Tapachula, Chiapas, Mexico. USDA-ARS.UCR::VicerrectorĂa de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de BiologĂ
Protection of Glial MĂĽller Cells by Dexamethasone in a Mouse Model of Surgically Induced Blood-Retinal Barrier Breakdown.
Purpose: Breakdown of the inner blood-retinal barrier (iBRB) occurs in many retinal disorders and may cause retinal edema often responsible for vision loss. Dexamethasone is used in clinical practice to restore iBRB. The aim of this study was to characterize the impact of a surgically induced iBRB breakdown on retinal homeostatic changes due to dystrophin Dp71, aquaporin-4 (AQP4), and Kir4.1 alterations in MĂĽller glial cells (MGC) in a mouse model. The protective effect of dexamethasone was assessed in this model. Moreover, retinal explants were used to control MGC exposure to a hypoosmotic solution containing barium. Methods: Partial lens surgery was performed in C57BL6/J mice. Dystrophin Dp71, AQP4, and Kir4.1 expression was analyzed by quantitative RT-PCR, Western blot, and immunohistochemistry. Twenty-four hours after surgery, mice received a single intravitreal injection of dexamethasone or of vehicle. Results: After partial lens surgery, iBRB permeability increased while Dp71 and AQP4 were downregulated and Kir4.1 was delocalized. These effects were partially prevented by dexamethasone injection. In the retinal explant model, MGC were swollen and Dp71, AQP4, and Kir4.1 were downregulated after exposure to a hypoosmotic solution containing barium, but not in the presence of dexamethasone. Heat shock factor protein 1 (HSF1) was overexpressed in dexamethasone-treated retinas. Conclusions: Partial lens surgery induces iBRB breakdown and molecular changes in MGC, including a downregulation of Dp71 and AQP4 and the delocalization of Kir4.1. Dexamethasone seems to protect retina from these molecular changes by upregulating HSF1
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