314 research outputs found
Finding alternatives to swidden agriculture:Does agroforestry improve livelihood options and reduce pressure on existing forest?
Swidden cultivation can contribute to deforestation and land degradation, which can subsequently result in a number of serious environmental problems. This paper examines the economic and social potential of agroforestry systems and the barriers to their widespread adoption, as a land use alternative to swidden cultivation, which may potentially help protect local forest. The Gunung Salak valley in West Java, Indonesia is presented as a case study. Based on farmers� and experts� assessment, costs and benefits have been estimated, which show that the two investigated agroforestry systems have higher net present value and benefit-cost ratio (B/C) than the two swidden cultivation systems. Tree ownership also creates more permanent rights to farmland and is prestigious in the community. Agroforestry products (fruit, vegetables etc.) have high monetary value and help strengthen social cohesion when shared with neighbors. However, farmers are reluctant to implement agroforestry. Stated reasons are related to both culture and capacity. Farmers practicing agroforestry are less involved in forest clearing and forest products collection than swidden farmers indicating that it may contribute positively to conservation of local forests. Increasing the adoption of agroforestry farming in the study area will require support to overcome capacity constraint
Distance and Regional Effects on the Value of Wild Bee Conservation
Many wild bee species are threatened across Europe, and with them the pollination function they provide. While numerous studies have assessed the value of bees as pollinators of crops, little is known about the non-marked value of bees. Using a choice modelling experiment, we examine these non-market values in Germany by identifying citizens’ willingness to pay (WTP) for wild bee conservation initiatives in four states. Effects of distance, state and regional affiliation are scrutinised, as previous research found these to affect respondents’ choices. Random parameter logit and latent class models are used to capture preference heterogeneity. Overall, we find strong support of wild bee conservation and a clear preference for improvement relative to the status quo, particularly in natural areas and for rare or endangered species. The yearly WTP for conservation initiatives ranges from 227 to 447€ per household. Our results show distance and regional effects on WTP. Initiatives in respondents’ home states are preferred, and increasing distance to initiatives in other states result in a slightly reduced WTP. Additionally, we observe regional preferences within an eastern and a western home region. These preferences are not explainable by socio-demographic characteristics, home state or distance and probably linked to social and cultural affiliations. We conclude that for widespread support in society and effective conservation initiatives, policy proposals must address this spatial heterogeneity from distance and regional effects. © 2022, The Author(s), under exclusive licence to Springer Nature B.V.The authors thank the anonymous reviewers for their extensive and valuable comments on this manuscript. The authors would further like to thank Julian Sagebiel from the Swedish University of Agricultural Sciences for his support in the analysis of the survey data. They thank Alice Rogowski, Bennet Bergmann, Helena Leinweber, Jan Peters, Jean Paul Moreaux, Thomas Prossliner, as well as the focus groups participants for their valuable comments on the early version of the questionnaire. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. C.M., B.D. and C.R. thank the Danish National Research Foundation for its support of the Center for Macroecology, Evolution and Climate (Grant No. DNRF96)
Simulation of Potts models with real q and no critical slowing down
A Monte Carlo algorithm is proposed to simulate ferromagnetic q-state Potts
model for any real q>0. A single update is a random sequence of disordering and
deterministic moves, one for each link of the lattice. A disordering move
attributes a random value to the link, regardless of the state of the system,
while in a deterministic move this value is a state function. The relative
frequency of these moves depends on the two parameters q and beta. The
algorithm is not affected by critical slowing down and the dynamical critical
exponent z is exactly vanishing. We simulate in this way a 3D Potts model in
the range 2<q<3 for estimating the critical value q_c where the thermal
transition changes from second-order to first-order, and find q_c=2.620(5).Comment: 5 pages, 3 figures slightly extended version, to appear in Phys. Rev.
A study of the etapipi channel produced in central pp interactions at 450 GeV/c
The reaction pp -> pf (eta pi pi) ps has been studied at 450 GeV/c. There is
clear evidence for an a2(1320)pi decay mode of the eta2(1645) and eta2(1870).
In addition, there is evidence for an a0(980)pi$ decay mode of both resonances
and an f2(1270)eta decay mode of the eta2(1870). No evidence is found for a JPC
= 2++ a2(1320)pi wave.Comment: 15 pages, Latex, 4 Figures Branching ratio a2pi /f2 eta correcte
A study of the f0(1370), f0(1500), f0(2000) and f2(1950) observed in the centrally produced 4pi final states
The production and decay properties of the f0(1370), f0(1500), f0(2000) and
f2(1950) have been studied in central pp interactions at 450 GeV/c. The dPT,
phi and |t| distributions of these resonances are presented. For the J = 0
states, the f0(1370) and f0(2000) have similar dPT and phi dependences. These
are different to the dPT and phi dependences of the f0(980), f0(1500) and
f0(1710). For the J = 2 states the f2(1950) has different dependences to the
f2(1270) and f2'(1520). This shows that the dPT and phi dependences are not
just J phenomena.Comment: 14 pages, Latex, 4 Figure
A search for charmonium states produced in central pp interactions at 450 GeV/c
A search for centrally produced charmonium states has been presented. There
is no significant evidence for any charmonium production. An upper limit of 2
nb is found for the cross section of chic production using the decay chic(1P)->
J/psi gamma.Comment: 10 pages, Latex, 4 Figure
A study of the centrally produced pi0pi0pi0 channel in pp interactions at 450 GeV/c
The reaction pp -> pf (pi0pi0pi0) ps has been studied at 450 GeV/c. The
pi0pi0pi0 effective mass spectrum shows clear eta(547) and pi2(1670) signals.
Branching ratios for the eta(547) and pi_2(1670) are given as well as upper
limits for the decays of the omega(782), a1(1260) and a2(1320) into 3pi0.Comment: 10 pages, Latex, 4 Figure
A coupled channel analysis of the centrally produced K+K- and pi+pi- final states in pp interactions at 450 GeV/c
A coupled channel analysis of the centrally produced K+K- and pi+pi- final
states has been performed in pp collisions at an incident beam momentum of 450
GeV/c. The pole positions and branching ratios to pipi and KK of the f0(980),
f0(1370), f0(1500) and f0(1710) have been determined. A systematic study of the
production properties of all the resonances observed in the pi+pi- and K+K-
channels has been performed.Comment: 16 pages, Latex, 5 Figure
Neutral-ionic phase transition : a thorough ab-initio study of TTF-CA
The prototype compound for the neutral-ionic phase transition, namely TTF-CA,
is theoretically investigated by first-principles density functional theory
calculations. The study is based on three neutron diffraction structures
collected at 40, 90 and 300 K (Le Cointe et al., Phys. Rev. B 51, 3374 (1995)).
By means of a topological analysis of the total charge densities, we provide a
very precise picture of intra and inter-chain interactions. Moreover, our
calculations reveal that the thermal lattice contraction reduces the indirect
band gap of this organic semi-conductor in the neutral phase, and nearly closes
it in the vicinity of the transition temperature. A possible mechanism of the
neutral-ionic phase transition is discussed. The charge transfer from TTF to CA
is also derived by using three different technics.Comment: 11 pages, 9 figures, 7 table
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