Suchergebnisse

Plantation forestry is making a significant positive contribution to the environment as well as to the livelihoods of millions of people in Asia. This chapter examines some of the major constraints facing commercial acacia and eucalypt plantations in South-east and East Asia and discusses adaptive actions in the face of climate change. Particular emphasis is placed on Vietnam and China but examples are also drawn from other parts of SE Asia where forest plantations are making a significant contribution to forest cover. The area of forest cover in Asia has declined greatly in the past 50 years due to an expanding population, and increasing demand for forest products and land for food and energy crops. For example, based on available documents, in 1943 Vietnam had 14.3 million ha of forests, with 43% forest cover; but by the year 1990 only 9.18 million ha remained, with a forest cover of 27.2%. During the period 1980 to 1990, the average forest lost was more than 100,000 ha each year. However, from 1990 to the present, the forest area has increased gradually, due to afforestation and rehabilitation of natural forest. Based on the official statement in Decision No. 1267/QD/BNN-KL-LN, dated 4 May 2009, as of 31 December 2009, the total national forest area was 13.2 million ha (forest cover of 39.1%), including 2.9 million ha of plantation forest. Recently, China too has also been able to reverse the decline in forest cover due to forest protection and afforestation. According to the 7th national forest resource inventory finished in 2008, there were 195.4 million ha (14.9 billion m3 of standing wood volume) of forest in China, an increase of 20.5 million ha (1.1 billion m3 standing wood volume) over the previous audit 5 years earlier. Of the increased forest area and volume, 3.9 million ha were from natural forests, and 8.4 million ha were from tree plantations. In the region, logging of natural forests is proceeding at alarming rates in some countries and is tightly controlled in others. In China, the "national natural forest protection program" was started in 2000, and any logging in natural forest is illegal, as is the case in Thailand. Following that the "national reforestation program" was initiated to established tree plantations in bare land for natural protection in north-west China and wood production in southern China. Forests are classified as ecological forests and natural forest reserves which the government will pay about 120 RMB per ha annually to the forest owners, or commercial forests for wood production. Likewise, the Government of Vietnam has given high priority to forest rehabilitation, as Program 327 and the 5 Million Hectare Rehabilitation Program (MHRP). Program 327, which lasted from 1993 until 1998, was effective in increasing afforestation and forest rehabilitation. The 5MHRP (1998 – 2010) had the objective of rehabilitating 5 million ha of forests and protecting existing forests, in order to increase forest cover to 43%. Unlike China and Thailand, Vietnam obtains more than 90% of its timber volume from natural forest.

Context. Accretion of gas from the intergalactic medium is required to fuel star formation in galaxies. We have recently suggested that this process can be studied using host galaxies of gamma-ray bursts (GRBs). Aims. Our aim is to test this possibility by studying in detail the properties of gas in the closest galaxy hosting a GRB (980425). Methods. We obtained the first ever far-infrared (FIR) line observations of a GRB host, namely Herschel/PACS resolved [C ii] 158 μm and [O i] 63 μm spectroscopy, and an APEX/SHeFI CO(2-1) line detection and ALMA CO(1-0) observations of the GRB 980425 host. Results. The GRB 980425 host has elevated [C ii]/FIR and [O i]/FIR ratios and higher values of star formation rates (SFR) derived from line ([C ii], [O i], Hα) than from continuum (UV, IR, radio) indicators. [C ii] emission exhibits a normal morphology, peaking at the galaxy centre, whereas [O i] is concentrated close to the GRB position and the nearby Wolf-Rayet region. The high [O i] flux indicates that there is high radiation field and high gas density at these positions, as derived from modelling of photo-dissociation regions. The [C ii]/CO luminosity ratio of the GRB 980425 host is close to the highest values found for local star-forming galaxies. Indeed, its CO-derived molecular gas mass is low given its SFR and metallicity, but the [C ii]-derived molecular gas mass is close to the expected value. Conclusions. The [O i] and H i concentrations and the high radiation field and density close to the GRB position are consistent with the hypothesis of a very recent (at most a few tens of Myr ago) inflow of atomic gas triggering star formation. In this scenario dust has not had time to build up (explaining high line-to-continuum ratios). Such a recent enhancement of star formation activity would indeed manifest itself in high SFR/SFR ratios because the line indicators are sensitive only to recent (∼ 10 Myr) activity, whereas the continuum indicators measure the SFR averaged over much longer periods (~100 Myr). Within a sample of 32 other GRB hosts, 20 exhibit SFR/SFR> 1 with a mean ratio of 1.74 ± 0.32. This is consistent with a very recent enhancement of star formation that is common among GRB hosts, so galaxies that have recently experienced inflow of gas may preferentially host stars exploding as GRBs. Therefore GRBs may be used to select a unique sample of galaxies that is suitable for the investigation of recent gas accretion. ; J.L.W. is supported by a European Union COFUND/Durham Junior Research Fellowship under EU grant agreement number 267209, and acknowledges additional support from STFC (ST/L00075X/1). A.K. acknowledges support from the Foundation for Polish Science (FNP) and the Polish National Science Center grant 2013/11/N/ST9/00400. A.J.C.T. acknowledges support from the Spanish Ministry Project AYA2015-71718-R. D.X. acknowledges the support by the One-Hundred-Talent Program of the Chinese Academy of Sciences, and by the Strategic Priority Research Program >Multi-wavelength Gravitational Wave Universe> of the Chinese Academy of Sciences (No. XDB23000000). ; Peer Reviewed

Irrigation occupies a central position in China?s crop production. However, due to low per capita water resources, much worse, unevenly distributed over regions and time and the rapid increase of water diversions to non-irrigation sectors, irrigation water shortages have become a very serious problem. Without the adoption of effective measures this problem may even threaten China?s food security. Currently, irrigation efficiency is very low in general, irrigation water prices cannot fully recover water supply costs, and irrigation facilities are aging due to the lack of funding for O&M (operation & maintenance). Since water prices are regulated by the government, and not determined by the market, water prices did not work effectively in water allocation. The adoption of more economic incentive measures, such as increasing water prices, has become the main strategy of the Chinese government. Since 1 January 2004, China has carried out a new water pricing regulation. The main objectives of this regulation are that water price should be increased to fully recover water supply cost and that water should be treated as a market good. In non-irrigation sectors, the consensus is that water price could be charged to fully recover water supply cost. However, there is still controversy over the charge of irrigation water pricing. Indeed, increasing water price to fully recover supply cost may seriously affect grain production, and farmers? income. Past studies in China on these issues mainly focused on the theoretical aspects of the problem, analyzing whether irrigation water price should be increased or not. Little studies have quantified the potential impact of the reforms in China. The following questions need to be elaborated: Are irrigation water pricing reforms effective?; What are the attitudes of the farmers towards the reforms?; How do farmers respond to water pricing reforms?; What comprehensive methods should be adopted to achieve the goals of the reforms? ; This project is based on the analysis of three case studies (Wudu, Jinghuiqu, and Shijin irrigation districts). Jinghuiqu is located in an arid region, Shijin is located in a semi-arid region and Wudu is located in the more humid Southwest. All the issues mentioned above, have been studied using econometric methods on the basis of the data gathered at the household, field canal, pump, and village level. The study reveals that the farmers? ability to pay for irrigation water is still low and that the current water prices reflect the farmers? willingness to pay, which implies that it is in fact very difficult to increase water prices further, let alone fully recover water supply cost. Farmers do not really participate in the irrigation management process, even at the field canal level, which limits the farmers? willingness to pay. In areas confronted with severe water shortages, such as in the Jinghuiqu and Shijin irrigation districts, it is estimated that the volume of water use significantly affects wheat and maize yields, and the reduction of field water use will lead to the decline of grain production. In such cases, although increasing irrigation water price will encourage farmers to reduce water use, it may also force them to decrease their grain production. These measures affect the farmers? revenues, which are largely dependent on crop production, thus increasing social inequities. Other policies need to protect weaker groups, such as poor farmers and farmers whose income mainly depends on crops. For instance, water property has still not been initialized and both irrigation bureaus and farmers lack incentives to adopt water-saving technologies. Initiating water property, expanding low-cost water-saving technologies, reforming irrigation management and fostering a water market are all important measures to achieve the policy goals of water-saving. At this point, it is necessary to emphasize that surface water price reforms may deeply affect groundwater resources use, especially in the conjunctive irrigation areas. Without the enhancement of groundwater resources management, saving surface water may lead to more overexploitation of groundwater resources, such was the case in the Jinghuiqu and Shijin irrigation districts. ; All in all, irrigation water price reforms represent a revolution when compared with traditional irrigation water resource management in China. Comprehensive and integrated policies should be carried out. China being such a large country, reforms cannot be uniform in all areas. Different areas, with different precipitation levels, should adopt different measures. In most parts of South China, volumetric water pricing is not appropriate, since this method requires large infrastructure investments. Collecting water fees on the basis of the farmers? irrigated area is an alternative policy, although it requires involving farmers in the irrigation management process. Even in the northern regions, the standards of irrigation infrastructure should not be overemphasized and more attention should be paid to the cost-benefits analysis of irrigation investments.

Whether stars could have driven the reionization of the intergalactic medium depends critically on the proportion of ionizing radiation that escapes the galaxies in which it is produced. Spectroscopy of gamma-ray burst (GRB) afterglows can be used to estimate the opacity to extreme ultraviolet (EUV) radiation along the lines-of-sight to the bursts. Assuming that long-duration GRBs trace the locations of the massive stars dominating EUV production, the average escape fraction of ionizing radiation can be calculated independently of galaxy size or luminosity. Here we present a compilation of H i column density (N HI ) measures for 140 GRBs in the range 1.6 < z < 6.7. Although the sample is heterogeneous, in terms of spectral resolution and signal-to-noise ratio, fits to the Ly α absorption line provide robust constraints on N HI , even for spectra of insufficient quality for other purposes. Thus we establish an escape fraction at the Lyman limit of (f esc ) ≈ 0.005, with a 98 per cent confidence upper limit of (f esc ) ≈ 0.015. This analysis suggests that stars provide a small contribution to the ionizing radiation budget at z < 5. At higher redshifts firm conclusions are limited by the small size of the GRB sample (7/140), but any decline in average H i column density seems to be modest. We also find no significant correlation of N HI with galaxy UV luminosity or host stellar mass. We discuss in some detail potential biases and argue that, while not negligible, systematic errors in f esc are unlikely to be more than a factor ~2 in either direction, and so would not affect the primary conclusions. Given that many GRB hosts are low-metallicity dwarf galaxies with high specific star-formation rates, these results present a particular problem for the hypothesis that such galaxies dominated the reionization of the Universe. © 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. ; JJ acknowledges support from Nederlandse Onderzoekschool Voor Astronomie(NOVA) and The Netherlands Organisation for Scientific Research (NWO) - The Sao Paulo Research Foundation (FAPESP) grant for advanced instrumentation in astronomy. KEH acknowledges support by a Project Grant (162948-051) from The Icelandic Research Fund. DAK acknowledges support from the Spanish research project AYA2014-58381-P and Juan de la Cierva Incorporacion IJCI-2015-26153. AJL and ERS acknowledge Science and Technology Facilities Council (STFC) consolidated grant ST/L000733/1. NRT and KW acknowledge Science and Technology Facilities Council (STFC) consolidated grant ST/N000757/1. AC acknowledges National Aeronautics and Space Administration (NASA) grant NNX15AP95A. AdUP acknowledges support from a Ramon y Cajal fellowship (RyC-2012-09975), a 2016 Banco Bilbao Vizcaya Argentaria (BBVA) Foundation Grant for Researchers and Cultural Creators, and from the Spanish research project AYA 2014-58381-P. RC acknowledges partial support from National Aeronautics and Space Administration (NASA) Swift grant NNX16AB04G.This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No. 725246). ; Peer Reviewed

How can we explain that some Popular education militants are also referring to the Information Society and thus seem to join this plan, carried to a great extent by merchants and the authorities ? Which are the stakes at work in this "meeting" ? Popular education, in addition to a long and plural history, is not homogeneous. However, Popular education is marked by a common philosophy aiming at developing social, cultural and political people's emancipation. In the mean time, political and economic authorities need to get the support of social actors to carry out the Information Society. Within this framework, associations would be the relay of the development of this society ; the necessary social mediator of this plan. Meanwhile, Popular education movements are seeking ways to appropriate this concept in order to make it able to serve the interests of Popular education. But they also question the specific purposes of this model. Indeed, the reference to the Information Society allows the militants of Popular education to update their traditional matters, and also to come out of the crisis they are facing. Lastly, if this meeting seems, at first sight, to generate consensus, the inherent conflicts in the confrontation of the values and identities do not therefore disappear and question the real stakes at work.

How can we explain that some Popular education militants are also referring to the Information Society and thus seem to join this plan, carried to a great extent by merchants and the authorities ? Which are the stakes at work in this "meeting" ? Popular education, in addition to a long and plural history, is not homogeneous. However, Popular education is marked by a common philosophy aiming at developing social, cultural and political people's emancipation. In the mean time, political and economic authorities need to get the support of social actors to carry out the Information Society. Within this framework, associations would be the relay of the development of this society ; the necessary social mediator of this plan. Meanwhile, Popular education movements are seeking ways to appropriate this concept in order to make it able to serve the interests of Popular education. But they also question the specific purposes of this model. Indeed, the reference to the Information Society allows the militants of Popular education to update their traditional matters, and also to come out of the crisis they are facing. Lastly, if this meeting seems, at first sight, to generate consensus, the inherent conflicts in the confrontation of the values and identities do not therefore disappear and question the real stakes at work.