5,895 research outputs found
Structural adjustment and forest resources - the impact of World Bank operations
Over two decades, the World Bank has undertaken many structural adjustment operations withgovernments of developing countries. During negotiations for structural adjustment loans (SALs), partner governments agree to specific policy reforms, whose implementation becomes a condition for disbursement of SAL funds. Conditionality varies with local circumstances, but generally supports privatization of state enterprises, liberalization of the domestic economy, and openness in international trade. Structural adjustment operations have often been controversial because they are explicitly political. Opposition, or support reflects ideological perspectives, perceptions of who gains, and who loses economically from a SAL, or beliefs about its environmental, and social impacts. Environmental groups express particular concern about SALs'impacts on the rate of deforestation. Debate about adjustment, and deforestation has been fueled largely by anecdotes, and a few country cases bases on limited time-series data. The authors broaden the analysis by combining a complete record of Bank SAL operations, with a 38-year socioeconomic database for 112 developing countries. They find that adjustment has greatly affected imports, exports, consumption, and production in many forest products sectors (such as fuel-wood, sawn-wood, panels, pulp, and paper). Some activities have increased, and some declined, but overall, the effects have balanced each other. The net impact on domestic round-wood production, the authors'proxy for forest exploitation, has been almost exactly zero. Their results suggest that growth in round-wood production is explained well by population growth, urbanization, and world demand for forest products. Their findings suggest that adjustment has not promoted domestic deforestation, but it has increased net imports of wood products, implying some displacement of pressure onto other countries'forest resources. They also find that devaluations have significantly increased the exploitation of forest resources.Environmental Economics&Policies,Labor Policies,Economic Theory&Research,Silviculture,Consumption,Environmental Economics&Policies,Economic Theory&Research,Silviculture,Forestry,Consumption
Sculpting the band gap: a computational approach
Materials with optimized band gap are needed in many specialized
applications. In this work, we demonstrate that Hellmann-Feynman forces
associated with the gap states can be used to find atomic coordinates with a
desired electronic density of states. Using tight-binding models, we show that
this approach can be used to arrive at electronically designed models of
amorphous silicon and carbon. We provide a simple recipe to include a priori
electronic information in the formation of computer models of materials, and
prove that this information may have profound structural consequences. An
additional example of a graphene nanoribbon is provided to demonstrate the
applicability of this approach to engineer 2-dimensional materials. The models
are validated with plane-wave density functional calculations.Comment: Submitted to Physical Review Letters on June 12, 201
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Analysis of curtailment at The Geysers geothermal Field, California
Geothermal energy has traditionally been viewed as a baseload energy source, but the rapid growth of intermittent renewable energy has led to a need for more flexibility in power generation to avoid mandatory curtailment imposed by grid operators. This study of curtailment at The Geysers provides insights into the magnitude, duration, frequency, temporal and spatial distribution, and potential causes of curtailment events between 2013 and 2018. Annual levels of curtailment range during this period from 9 to 47 GW h, representing 0.15 to 0.81 % of the net generation. Most curtailments occurred at the power plants connected to a lower capacity transmission line and may result from transmission constriction. There is a clear link between negative pricing and economic curtailment, especially when solar production is higher. Economic curtailment events tend to be only a few hours and vary in magnitude up to almost 300 MW, whereas transmission-related curtailment events can be up to several weeks in duration. It is likely that curtailment of geothermal power will be an increasing concern, and could be mitigated by flexible generation strategies and increases in energy storage. It is critical to know the nature of curtailment events so that flexible generation options can be assessed properly
A Novel Beamformed Control Channel Design for LTE with Full Dimension-MIMO
The Full Dimension-MIMO (FD-MIMO) technology is capable of achieving huge
improvements in network throughput with simultaneous connectivity of a large
number of mobile wireless devices, unmanned aerial vehicles, and the Internet
of Things (IoT). In FD-MIMO, with a large number of antennae at the base
station and the ability to perform beamforming, the capacity of the physical
downlink shared channel (PDSCH) has increased a lot. However, the current
specifications of the 3rd Generation Partnership Project (3GPP) does not allow
the base station to perform beamforming techniques for the physical downlink
control channel (PDCCH), and hence, PDCCH has neither the capacity nor the
coverage of PDSCH. Therefore, PDCCH capacity will still limit the performance
of a network as it dictates the number of users that can be scheduled at a
given time instant. In Release 11, 3GPP introduced enhanced PDCCH (EPDCCH) to
increase the PDCCH capacity at the cost of sacrificing the PDSCH resources. The
problem of enhancing the PDCCH capacity within the available control channel
resources has not been addressed yet in the literature. Hence, in this paper,
we propose a novel beamformed PDCCH (BF-PDCCH) design which is aligned to the
3GPP specifications and requires simple software changes at the base station.
We rely on the sounding reference signals transmitted in the uplink to decide
the best beam for a user and ingeniously schedule the users in PDCCH. We
perform system level simulations to evaluate the performance of the proposed
design and show that the proposed BF-PDCCH achieves larger network throughput
when compared with the current state of art algorithms, PDCCH and EPDCCH
schemes
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Towards a Theory of Practice: Critical Transdisciplinary Multiliteracies
About the book: Education institutions and organizations throughout the world are currently being held accountable for achieving and maintaining historically unmatched standards of academic quality and performance. Accreditation bodies; policy makers; boards of trustees; and teacher, parent, and student groups all place educational institutions and organizations under unprecedented accountability pressures. The aim of this volume is to explore and better understand how these pressures are impacting a broad range of social and cultural issues and, subsequently, how these issues impact student motivation and learnin
A heuristic for the distribution of point counts for random curves over a finite field
How many rational points are there on a random algebraic curve of large genus
over a given finite field ? We propose a heuristic for this
question motivated by a (now proven) conjecture of Mumford on the cohomology of
moduli spaces of curves; this heuristic suggests a Poisson distribution with
mean . We prove a weaker version of this statement in which
and tend to infinity, with much larger than .Comment: 16 pages; v2: refereed version, Philosophical Transactions of the
Royal Society A 201
Extended release delivery system of metoprolol succinate using hot-melt extrusion: effect of release modifier on methacrylic acid copolymer
The current study reports on the manufacturing of extended release dosage forms of metoprolol succinate via hot-melt extrusion (HME) technology. Either Eudragit®S100 and Eudragit®L100 alone or in combination with release modifying agent Polyox™ WSR 303 and Eudragit®L100-55 were processed to obtain complete and faster release. Metoprolol succinate with similar solubility parameters to polymer was dispersed in polymer matrix and was characterized by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscopy (SEM).
Stability of drug after extrusion was confirmed by thermogravimetric analysis and high-performance liquid chromatography. Physical characterization method exhibited that the drug was homogeneously dispersed in non-crystalline state in
Eudragit®L100-55-based formulations whereas in semi-crystalline state in Polyox™ WSR 303. The drug release percentage was below 3 and 40% in 0.1 N HCL with Eudragit®L100-55- and Polyox™ WSR 303-containing formulations, respectively, and exhibited pH-dependent dissolution properties. The drug-release mechanism was anomalous with Polyox™ WSR 303 formulations whereas diffusion through pore formation was obtained with Eudragit®L100-55. Both Eudragit®L100-55 and Polyox™ WSR 303 changed the release mechanism and kinetics of drug release from thermally processed dosage forms. The
optimized stable formulation is similar to the marketed formulation with F2 value of 72.36. Thus, it can be concluded that HME was exploited as an effective process for the preparation of controlled release matrix system based on pH-dependent polymer matrices Eudragit®S100 and Eudragit®L100
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