133 research outputs found
Effects of industrial plantations on ecosystem services and livelihoods : Perspectives of rural communities in China
This paper addresses the current research void on local community views of changes in ecosystem services associated with rapid land use transformation in the context of plantation-based forestry. This interview-based study, conducted in southern China, aims at assessing the perspectives of local communities of: 1) the effects of Eucalyptus industrial plantations on selected ecosystem services and on local development; and 2) opportunities for future community livelihood development, based on the relations with the government and with forest industry operating locally. We analysed data from semi-structured interviews with 70 villagers for their views on changes in ecosystem services after the establishment of plantations, and their future expectations on the local livelihood development. Most interviewees mentioned some negative development on environmental quality after the establishment of the industrial plantations, especially on soil and water. Furthermore, the reduced productivity of cropland surrounding industrial plantations, coupled with other financial drivers, induced several villagers to switch from agricultural crops to household plantations. In the absence of destructive typhoons, household plantations can provide owners more free time, higher income, while industrial plantations provided some employment opportunities. Interviewees' expectations for the future included receiving financial support and capacity building for household plantations and crops, support to local roads and schools, and higher employment opportunities. Some interviewees suggested that solutions should be implemented for improving degraded water quality, while others suggested reducing forestry operations. Even though being highly context-specific, our findings open up the discussion about the further community development opportunities in the context of plantation forestry. In particular, the potential of value sharing mechanisms between the private sector and the local communities should be further studied. (C) 2017 The Authors. Published by Elsevier Ltd.Peer reviewe
Incommensurable preferences in contingent valuation: the case of Natura 2000 Network in Finland
Recognition of differences in the capacity to deal with floodsâA cross-country comparison of flood risk management
Flood risks worldwide are increasing due to climate change. Managing these risks is ever more necessary. Although flood risk management (FRM) is often understood as a technical challenge, it also involves decisions about the distribution of resources and risks in floods, which can be inherently unfair. People are disparately affected by floods due to their location. Because of their various socioeconomic and demographic characteristics, they also differ in their capacity to deal with floods. These differences need to be recognised in FRM to prevent disproportionate impacts on vulnerable communities. However, at present, a knowledge gap exists on how to make FRM more inclusive and just, and discussions on recognition justice in the context of FRM are scarce. This article therefore examines recognition of differences in the capacity of people to deal with floods in FRM in England (United Kingdom), Finland, Flanders (Belgium) and France. We analyse if, and how, these differences are recognised in FRM policy and practice and through decision-making procedures, drawing on examples from the implementation of five FRM strategies in each country (flood risk prevention, flood defence, flood risk mitigation, flood preparation and flood recovery). Furthermore, we aim to highlight opportunity spaces to strengthen recognition justice in future FRM
The origin of redshift asymmetries: How LambdaCDM explains anomalous redshift
Several authors have found a statistically significant excess of galaxies
with higher redshifts relative to the group centre, so-called discordant
redshifts, in particular in groups where the brightest galaxy, identified in
apparent magnitudes, is a spiral. Our aim is to explain the observed redshift
excess. We use a semi-analytical galaxy catalogue constructed from the
Millennium Simulation to study redshift asymmetries in spiral-dominated groups
in the Lambda cold dark matter (LambdaCDM) cosmology. We show that discordant
redshifts in small galaxy groups arise when these groups are gravitationally
unbound and the dominant galaxy of the group is misidentified. The redshift
excess is especially significant when the apparently brightest galaxy can be
identified as a spiral, in full agreement with observations. On the other hand,
the groups that are gravitationally bound do not show a significant redshift
asymmetry. When the dominant members of groups in mock catalogues are
identified by using the absolute B-band magnitudes, our results show a small
blueshift excess. This result is due to the magnitude limited observations that
miss the faint background galaxies in groups. When the group centre is not
correctly identified it may cause the major part of the observed redshift
excess. If the group is also gravitationally unbound, the level of the redshift
excess becomes as high as in observations. There is no need to introduce any
"anomalous" redshift mechanism to explain the observed redshift excess.
Further, as the Friends-of-Friends percolation algorithm picks out the
expanding parts of groups, in addition to the gravitationally bound group
cores, group catalogues constructed in this way cannot be used as if the groups
are purely bound systems.Comment: Accepted for publication in A&
Scattering of therapeutic radiation in the presence of craniofacial bone reconstruction materials
PurposeRadiation scattering from bone reconstruction materials can cause problems from prolonged healing to osteoradionecrosis. Glass fiber reinforced composite (FRC) has been introduced for bone reconstruction in craniofacial surgery but the effects during radiotherapy have not been previously studied. The purpose of this study was to compare the attenuation and back scatter caused by different reconstruction materials during radiotherapy, especially FRC with bioactive glass (BG) and titanium.MethodsThe effect of five different bone reconstruction materials on the surrounding tissue during radiotherapy was measured. The materials tested were titanium, glass FRC with and without BG, polyether ether ketone (PEEK) and bone. The samples were irradiated with 6Â MV and 10Â MV photon beams. Measurements of backscattering and dose changes behind the sample were made with radiochromic film and diamond detector dosimetry.ResultsAn 18% dose enhancement was measured with a radiochromic film on the entrance side of irradiation for titanium with 6Â MV energy while PEEK and FRC caused an enhancement of 10% and 4%, respectively. FRCâBG did not cause any measurable enhancement. The change in dose immediately behind the sample was also greatest with titanium (15% reduction) compared with the other materials (0â1% enhancement). The trend is similar with diamond detector measurements, titanium caused a dose enhancement of up to 4% with a 1Â mm sample and a reduction of 8.5% with 6Â MV energy whereas FRC, FRCâBG, PEEK or bone only caused a maximum dose reduction of 2.2%.ConclusionsGlass fiber reinforced composite causes less interaction with radiation than titanium during radiotherapy and could provide a better healing environment after bone reconstruction.</p
LABOCA observations of nearby, active galaxies
We present large scale 870 micron maps of the nearby starburst galaxies
NGC253, NGC4945 and the nearest giant elliptical radio galaxy Centaurus A (NGC
5128) obtained with the newly commissioned Large Apex Bolometer Camera (LABOCA)
operated at the APEX telescope. Our continuum images reveal for the first time
the distribution of cold dust at a angular resolution of 20" across the entire
optical disks of NGC253 and NGC4945 out to a radial distance of 10' (7.5 kpc).
In NGC5128 our LABOCA image also shows, for the first time at submillimeter
wavelengths, the synchrotron emission associated with the radio jet and the
inner radio lobes. From an analysis of the 870 micron emission in conjunction
with ISO-LWS, IRAS and long wavelengths radio data we find temperatures for the
cold dust in the disks of all three galaxies of 17-20 K, comparable to the dust
temperatures in the disk of the Milky Way. The total gas mass in the three
galaxies is determined to be 2.1, 4.2 and 2.8 x 10^9 solar masses for NGC253,
NGC4945 and NGC5128, respectively. A detailed comparison between the gas masses
derived from the dust continuum and the integrated CO(1-0) intensity in NGC253
suggests that changes of the CO luminosity to molecular mass conversion factor
are mainly driven by a metallicity gradient and only to a lesser degree by
variations of the CO excitation. An analysis of the synchrotron spectrum in the
northern radio lobe of NGC5128 shows that the synchrotron emission from radio
to the ultraviolet wavelengths is well described by a broken power law and that
the break frequency is a function of the distance from the radio core as
expected for aging electrons. We derive an outflow speed of ~0.5c at a distance
of 2.6kpc from the center, consistent with the speed derived in the vicinity of
the nucleus.Comment: 12 pages, 11 figures. Accepted for publication in A&
Day-Scale Variability of 3C 279 and Searches for Correlations in Gamma-Ray, X-Ray, and Optical Bands
Light curves of 3C 279 are presented in optical (R-band), X-rays (RXTE/PCA),
and gamma rays (CGRO/EGRET) for 1999 Jan-Feb and 2000 Jan-Mar. During both of
those epochs the gamma-ray levels were high, and all three observed bands
demonstrated substantial variation, on time scales as short as one day.
Correlation analyses provided no consistent pattern, although a rather
significant optical/gamma-ray correlation was seen in 1999, with a gamma-ray
lag of ~2.5 days, and there are other suggestions of correlations in the light
curves. For comparison, correlation analysis is also presented for the
gamma-ray and X-ray light curves during the large gamma ray flare in 1996 Feb
and the two gamma-bright weeks leading up to it; the correlation at that time
was strong, with a gamma-ray/X-ray offset of no more than 1 day.Comment: 20 pages, including 7 figures; accepted by The Astrophysical Journa
Optical and radio variability of the BL Lac object AO 0235+16: a possible 5-6 year periodicity
New optical and radio data on the BL Lacertae object AO 0235+16 have been
collected in the last four years by a wide international collaboration, which
confirm the intense activity of this source. The optical data also include the
results of the Whole Earth Blazar Telescope (WEBT) first-light campaign
organized in November 1997. The optical spectrum is observed to basically
steepen when the source gets fainter. We have investigated the existence of
typical variability time scales and of possible correlations between the
optical and radio emissions by means of visual inspection, Discrete Correlation
Function analysis, and Discrete Fourier Transform technique. The major radio
outbursts are found to repeat quasi-regularly with a periodicity of about 5.7
years; this period is also in agreement with the occurrence of some of the
major optical outbursts, but not all of them.Comment: to be published in A&
Dense Gas in Nearby Galaxies: XVII. The Distribution of Ammonia in NGC253, Maffei2 and IC342
The central few 100 pc of galaxies often contain large amounts of molecular
gas. The chemical and physical properties of these extragalactic star formation
regions differ from those in galactic disks, but are poorly constrained. This
study aims to develop a better knowledge of the spatial distribution and
kinetic temperature of the dense neutral gas associated with the nuclear
regions of three prototypical spiral galaxies, NGC253, IC342, and Maffei2. VLA
CnD and D configuration measurements have been made of three ammonia (NH3)
inversion transitions. The (J,K)=(1,1) and (2,2) transitions of NH3 were imaged
toward IC342 and Maffei2. The (3,3) transition was imaged toward NGC253. The
entire flux obtained from single-antenna measurements is recovered for all
three galaxies observed. Derived lower limits to the kinetic temperatures
determined for the giant molecular clouds in the centers of these galaxies are
between 25 and 50K. There is good agreement between the distributions of NH3
and other H2 tracers, such as rare CO isotopologues or HCN, suggesting that NH3
is representative of the distribution of dense gas. The "Western Peak" in IC342
is seen in the (6,6) line but not in lower transitions, suggesting maser
emission in the (6,6) transition.Comment: 13 pages, 8 figures, latex format, accepted by A&
Multi-Epoch Multiwavelength Spectra and Models for Blazar 3C~279
Of the blazars detected by EGRET in GeV gamma rays, 3C 279 is not only the
best-observed by EGRET, but also one of the best-monitored at lower
frequencies. We have assembled eleven spectra, from GHz radio through GeV gamma
rays, from the time intervals of EGRET observations. Although some of the data
have appeared in previous publications, most are new, including data taken
during the high states in early 1999 and early 2000. All of the spectra show
substantial gamma-ray contribution to the total luminosity of the object; in a
high state, the gamma-ray luminosity dominates over that at all other
frequencies by a factor of more than 10. There is no clear pattern of time
correlation; different bands do not always rise and fall together, even in the
optical, X-ray, and gamma-ray bands.
The spectra are modeled using a leptonic jet, with combined synchrotron
self-Compton + external Compton gamma-ray production. Spectral variability of
3C 279 is consistent with variations of the bulk Lorentz factor of the jet,
accompanied by changes in the spectral shape of the electron distribution. Our
modeling results are consistent with the UV spectrum of 3C 279 being dominated
by accretion disk radiation during times of low gamma-ray intensity.Comment: 39 pages including 13 figures; data tables not included (see ApJ web
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