bluuebunny/crossref_metadata_2025_split huggingface dataset:
The relationship of ground motion hazard to the design of tall buildings
Authors: Lew Marshall 
Published: October 2009

AbstractMany tall buildings in high seismic regions of the USA are being designed using performance‐based earthquake engineering (PBEE) principles under alternative design procedures. Still‐evolving PBEE design criteria for tall buildings generally require that these buildings be designed for collapse prevention due to earthquake ground motion hazard (with a long recurrence interval, on the order of 2475 years corresponding to a 2% probability of being exceeded in 50 years). Alternative design criteria for tall buildings generally specify some deviations from prescriptive building code provisions, thus allowing for greater building heights, use of high strength materials and less structural redundancy, among other things. Because of the deviations from prescriptive provisions, nonlinear response history analysis is required and earthquake time histories are required. When using probabilistic seismic hazard analysis, the ground motions developed for very rare earthquakes are generally dominated by uncertainties. There is great difficulty in identifying or developing realistic strong ground motion time histories for these rare events. In addition, accounting for source‐to‐site effects (such as basin, near‐source and directivity) becomes increasingly complex. Developing representative ground motion time histories may involve scaling or modification of actual time histories, in the time or frequency domains, to match the target spectrum. Copyright © 2009 John Wiley & Sons, Ltd.
Estimation method of tall building structure system in architecture project design
Authors: Shi Jianguang , Hua Linlin , Han Tong 
Published: October 2009

AbstractArchitecture project design is a key stage to tall building design because its structure form, structure system and main member dimension may be determined, and the possibility to influence construction cost may attain 70–80% in this stage. Based on building conditions in architecture project design, such as building function, storeys, height, length/width ratio, height/width ratio, floor height and the maximum wind pressure, seismic intensity and site type, one of the estimation methods for building structure behaviour under these combined action is presented. In this method, every storey in the building is taken as a macro‐element. The member in the building, such as beams, columns, walls and slabs, are included in the macro‐element. Considering the contribution of each member, the macro‐element stiffness is established for each storey. Then, the estimation analysis of the building structure is carried out following the finite element method. Comparing the analysis results, such as internal force and storey deformation with the usual analysis method, it is known that this estimation analysis method can be used to estimate the behaviour of the building structure system in architecture project design. It is also a useful tool to architects and structure engineers in estimating the applicability of the structure system. Copyright © 2009 John Wiley & Sons, Ltd.
New deterministic and stochastic simulation models for non‐isotropic scattering mobile‐to‐mobile Rayleigh fading channels
Authors: Cheng Xiang , Wang Cheng‐Xiang , Laurenson David I. , Salous Sana , Vasilakos Athanasios V. 
Published: October 2009

AbstractFor the practical simulation and performance evaluation of mobile‐to‐mobile (M2M) communication systems, it is desirable to develop accurate M2M channel simulation models for more realistic scenarios of non‐isotropic scattering. In this paper, by using a ‘double‐ring’ concept to describe M2M non‐isotropic scattering environments, we propose new deterministic and stochastic sum‐of‐sinusoids (SoS) based simulation models. The proposed simulation models extensively consider the distributions of the angle of arrival (AoA) and the angle of departure (AoD), and thus provide a good approximation to the desired statistical properties of the reference model. Copyright © 2009 John Wiley & Sons, Ltd.
Medium access control in vehicularad hocnetworks
Authors: Leng Supeng , Fu Huirong , Wang Qing , Zhang Yan 
Published: October 2009

AbstractThe distinguishing properties of VehicularAd hocwireless Networks (VANETs) strongly challenge the design of Medium Access Control (MAC) protocols, which are responsible for the medium access coordination among active vehicles, as well as the accommodation of both driving safety applications and non‐safety applications. In this paper, we focus on a comprehensive survey of VANET MAC schemes by integrating various related issues and challenges. Our analysis not only deepens the understanding of MAC techniques in VANETs but also presents the key ideas and potential directions for future research in this area. In order to significantly improve the communication performance of VANETs, more research efforts on MAC techniques must be made for optimizing multichannel coordination and allocation approaches, enhancing the Quality of Service (QoS) capability, and combating the hidden terminal problem, broadcast storm problem and even ACK (acknowledgment) explosion problem. Copyright © 2009 John Wiley & Sons, Ltd.
Mechanochemical Synthesis of New Coordination Polymers with Acetylenedicarboxylate as Bridging Ligand
Authors: Stein Irena , Ruschewitz Uwe 
Published: October 2009

AbstractCaADC (1) and Mg(ADC)(H2O)2 (2) were synthesized by grinding Ca(CH3COO)2 and Mg(CH3COO)2·4H2O with acetylenedicarboxylic acid (H2ADC) in an agate mortar. After careful heating for two hours in an argon atmosphere at moderate temperatures, 50 °C and 70 °C, respectively, polycrystalline materials of good crystallinity were obtained. The crystal structures of 1 and 2 were solved and refined from X‐ray powder diffraction data. In the course of the structural refinement it turned out that 1 and 2 are isotypic to SrADC(I41/amd, Z = 4) and Mn(ADC)(H2O)2 (I2/a, Z = 4). In both compounds metal cations are connected by bridging ADC2– ligands to form a 3D coordination network. Thermoanalytical investigations show that CaADC decomposes above 50 °C, whereas for Mg(ADC)(H2O)2 a mass loss of approx. 33 % is observed above 150 °C. The loss of one water molecule as well as a decarboxylation is very likely. The remaining residue is amorphous to X‐rays.
Surgical Education in Brazil
Authors: Ferreira Eugênio Américo Bueno , Rasslan Samir 
Published: October 2009

AbstractBackgroundThe surgical residency was implemented in Brazil in 1944. Gradually, several programs were created under the auspices of the National Committee of Medical Residency (Comissão Nacional de Residência). A candidate for a residency program is submitted to a selection process in various institutions. One of the greatest obstacles to medical education in Brazil is that the number of graduate students is much larger than the number of available vacancies. As a consequence, they end up looking for other alternatives to their professional training, and these cannot offer the same results as a formal residency. Regarding the current residency program in surgery, Brazil has roughly 200 general surgery programs, which offer 1,040 vacancies yearly.Method and resultsThe surgical residency program lasts 2 years with rotation in various surgical specialties, which is a requirement for the following years in specific specialties. The 1,040 who are enrolled in the first 2 years of a residency in surgery take a new examination to continue their training. Here, there are only 573 vacancies; therefore, 45% of the newly trained surgeons start a practice or become apprentices. The 573 residents who move on to further education then pass 2 years in basic general surgery at an institution and continue in the same or are transferred to another department. The next training period should be 2 or 3 years, depending on the specialty. The General Surgery program lasts 4 years: two initial basic years and two more years of training in elective, emergency, and trauma surgery and intensive care. The objective is to become competent in the diagnosis and treatment of the most common diseases that affect the community.ConclusionsMedical entities in specialties have their own selection process to grant the title of specialist. The Brazilian College of Surgeons (Colégio Brasileiro de Cirurgiões) is responsible for granting the title “general surgeon,” following the model of the American Board of Surgery.
Non‐Evaporative Solvent Recovery Step in Deacidification of Used Frying Oil as Biodiesel Feedstock by Methanol Extraction
Authors: Tunc Meliz Fatma , Gurbuz Hale , Türkay Selma Zeynep 
Published: October 2009

AbstractAn alternative deacidification process combining a liquid–liquid extraction with a non‐evaporative solvent recovery step was proposed for preparing used frying oil (UFO) as biodiesel feedstock. The liquid–liquid extraction step using methanol was simulated for obtaining refined UFO with a final residual free fatty acids (FFA) content ≤ 1%. Solvent recovery step of the process, which is based on the precipitation of FFA with Ca(OH)2 as insoluble calcium soaps, was investigated experimentally. With the aim of maximizing the FFA removal from the methanol extract, the influence of process variables such as FFA concentration in the extract phase, Ca(OH)2 amount, stirring rate and temperature were investigated by using model extract phases. Complete removal of FFA was achieved in 30, 20, and 15 min, from the extract phases containing 3.86, 7.78, and 11.58 wt% FFA, respectively, when the precipitation was carried out at a temperature of 65 °C, stirring rate of 250 rpm and by using 18 times the stoichiometric Ca(OH)2 amount. The precipitate quickly settled down due to the agglomeration, thereby provided an efficient and easy separation of the methanol from the solids. Provided the final residual content of FFA in methanol was too low, recovered methanol can be recycled for more FFA extraction. Although the suggested process offers a feasible method for preparing UFO as biodiesel feedstock, the effect of other decomposition products in UFO must be investigated in depth for using such a process on an industrial scale.
Public policy and genomic science: Managing dynamic change
Authors: Mintrom Michael , Williams Claire 
Published: October 2009

AbstractDevelopments in genomic science and its applications raise significant public policy issues. Restrictive governance regimes can inhibit progress that has the potential to significantly enhance social and economic outcomes. But permissive regimes run the risk of mistakes, inappropriate management practices, and accidents having costly effects on human populations, various agricultural activities, and ecosystems. This article provides an overview of genomic science. We survey public policy issues raised by this science and how existing public policy models and approaches have been used to consider and address them. Issues covered include the quality of the science, non-human applications, human applications, and social impacts. From here, attention turns to challenges posed both at the conceptual and practical level that are expected to promote further policy learning. We consider the need for effective oversight and regulatory regimes, and greater transparency and participation in decision-making. The article also introduces the other contributions to this theme issue of Policy and Society.
Environmental consequences of modern production agriculture: How can alternative agriculture address these issues and concerns?
Authors: Papendick Robert I. , Elliott Lloyd F. , Dahlgren Robert B. 
Published: October 2009

AbstractModern large-scale conventional agriculture with intensive monoculture and row-cropping practices often results in unacceptable soil erosion and runoff and in associated losses of nutrients and pesticides. It also adversely affects wildlife. Sediment from erosion is the greatest pollutant of surface water in the United States and is a major carrier of agrichemicals into the water system. Conservation tillage practices can significantly reduce soil losses in modern production systems, but pollution of surface and groundwaters from runoff and associated potential for increased use of pesticides may still present a hazard. Erosion can be reduced to tolerable levels by the use of crop rotations, meadow crops, and mulch tillage, as commonly used in alternative agriculture. These cultural practices also result in diversity in crop types and in smaller fields, with possible benefit to many wildlife species. Chemical threats to the environment and to wildlife are reduced because synthetic chemicals are used sparingly or not at all.
The role of sustainable agriculture in improving the safety and quality of the food supply
Authors: Clancy Katherine L. 
Published: October 2009

AbstractAgricultural and health policies are not integrated in the U.S. despite their obvious similarities and linkages. Sustainable agriculture can undoubtedly play an important role in joining the two sectors; however, before this can occur research is needed to answer questions in many areas. Some consumer concerns regarding the safety of the food supply can be abated through the use of sustainable practices in food production and processing which can lessen exposure to toxic contaminants and conserve resources. Among the farming issues considered here are pesticide toxicities and their synergistic interactions, yields, storability, nutrient quality, nitrates, mycotoxins, and antibiotics used in meat production. The manipulation of commodities during processing is also addressed, including the intense refining of grains, fortification and vitamin supplementation, imitation food, and food additives. Analogies between production and processing operations are drawn and specific research needs identified.
The economic implications of organic farming
Authors: Cacek Terry , Langner Linda L. 
Published: October 2009

AbstractMany farmers are turning to organic or “low input” farming as a strategy for economic survival. Several comparisons of actual grain farms in the central and northern states showed that organic farming equals or exceeds conventional farming in economic performance. These findings are supported by studies that used yield data from research plots as inputs to economic models. However, models that relied more heavily on hypothetical data showed an economic disadvantage for organic farming. This may have been a result of the failure of the hypothetical models to incorporate valid assumptions on conservation and efficient utilization of water, nutrients, fuel, labor, and capital. Established organic farmers are less vulnerable to natural and economic risks than conventional farmers because their systems are more diversified. They also are less able, however, to take advantage of income tax deductions. Future trends in commodity prices, input prices, pollution regulation, and research can be expected to have mixed effects on conventional and organic farmers, but the net impact will probably favor organic farmers. On a macroeconomic (i.e. national) scale, conversion to organic farming would have many benefits. It would reduce federal costs for supporting commodity prices, reduce depletion of fossil fuels, reduce the social costs associated with erosion, improve fish and wildlife habitats, and insure the productivity of the land for future generations. However, widespread conversion to organic farming would have an undesirable impact on the balance of trade. Future research on the economics of organic farming at the farm or microeconomics level should be directed at horticultural crops, southern latitudes, marketing, and the process of conversion from conventional to organic farming. Future macroeconomic research should quantify the social benefits described above, enabling decision makers to compare organic farming with other policy options.
Alternative production systems to reduce nitrates in ground water
Authors: Papendick Robert I. , Elliott Lloyd F. , Power James F. 
Published: October 2009

AbstractEvidence indicates a strong positive relationship between increases in nitrogen fertilizer use on cropland and nitrate concentrations in shallow ground water. This raises concern about the fate and efficiency of nitrogen fertilizer with current farming practices. Approximately 50 percent of the nitrogen fertilizer applied may be recovered by agronomic crops and 35 percent or less removed in the harvested grain of a crop such as corn. The residual nitrogen is subject to loss by several processes, one being leaching from the crop root zone. Alternative production systems that provide ground water protection must give attention to improved management of nitrogen fertilizer and to practices that minimize the need for nitrogen fertilizer and reduce soil nitrate concentrations. Most important in nitrogen fertilizer management is to more closely match nitrogen availability in the soil with crop needs and to avoid over-fertilization. Nitrogen fertilizer use can be reduced by alternate cropping of low and high nitrogen-demanding crops, use of legumes in the crop rotation to fix nitrogen, and proper use of manures, crop residues, and other organic wastes. Residual nitrates in soil can be reduced by use of cover crops, nitrogen-scavenging crops in the rotation, and alternating shallow and deep-rooted crops. Conservation tillage alone as used with many conventional cropping systems will probably not change the current status of nitrate leaching. Practices used by organic farmers should be carefully studied as possible approaches for ground water protection and adaptation into conservation tillage systems for conserving soil and water resources.
Agriculture and ground water quality: A public policy perspective
Authors: Abdalla Charles W. , Libby Lawrence W. 
Published: October 2009

AbstractAgricultural production is an important source of ground water contamination in many regions of the U.S. Ground water contamination is the unintended side effect of actions by economic agents pursuing their interests within the legal framework established by current public policy. Under existing policy, agricultural producers do not have changes as noted to consider off-site effects of their decisions on ground water supplies. Given these policy rules, producers can be expected to cause such damage until their rights and obligations are adjusted by policy. The farmer is simply responding in a predictable manner to opportunities existing within the economic system. Possible rationales for government action to protect ground water quality include: 1) the existence of “third party” effects in the form of off-site damages associated with degraded water supplies; 2) overuse of an “open-access” resource; 3) society's desire to make conservative ground water management decisions to avoid the risks of contamination; and 4) individuals' demands for ground water protection even though they may not expect to directly benefit. Alternative policy instruments for ground water protection include taxes, subsidies, regulations and prohibitions, education, and public spending. Different policy approaches are being employed to address agricultural contamination of ground water. One policy approach emphasizes producers ' lack of accurate information and appropriate decision-making, and recommends educating farmers about how their profits can be increased by improved decisions regarding inputs. A second approach is to change the rules and incentives to compel or induce producers to act in a way that improves ground water quality. If ground water quality follows the pattern of most public issues, effective policies will be developed only as the cost of failing to act becomes known. Research and delivery of information on the costs of ground water protection and the costs of not protecting ground water are likely to be key factors affecting the formation of future ground water quality policies.
Legumes: Their potential role in agricultural production
Authors: Power James F. 
Published: October 2009

AbstractThe energy crisis of the late 1970's has raised the question of the wisdom of depending upon fertilizer nitrogen as the primary source of N input into crop production systems. While present and past price structures have favored fertilizer-N over biologically fixed N, there are a number of other benefits of legumes in a cropping system in addition to their effects on N availability. Among these are less potential for environmental degradation and improved soil physical conditions and water relations, but it is difficult to assign economic value to many such benefits. In addition to the economics of the present price structure, disadvantages of using legumes could include reduced total production and increased need for livestock in a farming enterprise (these could be considered assets from some aspects). Legumes are presently used in shortterm rotation, such as corn-soybean, or in continuous corn with a legume winter cover crop. These systems are finding widespread use and offer the producer many benefits, as well as helping to solve several major environmental problems associated with N use in agriculture.
Riparian forest communities and their role in nutrient conservation in an agricultural watershed
Authors: Fail Joseph L. , Haines Bruce L. , Todd Robert L. 
Published: October 2009

AbstractRiparian forests situated adjacent to agricultural uplands were studied to test the hypothesis that riparian forests intercept and utilize nutrients lost from these uplands. Production rates, tissue nutrient concentrations, and nutrient accretion rates of woody plants were compared between sites that were contiguous to agricultural areas (test sites) and sites that were separated from agricultural areas by grass buffer zones (reference sites). Net primary production was 10,344 kg ha–1yr–1, but trees within a riparian forest that received runoff directly from a pigpen (test site) had production rates that were 2.5 times higher than the average for all other sites. Above ground forest nutrient accretion rates were also highest at the pigpen test site. Woody plants in test site forests had, on the average, higher branch wood and leaf nutrient concentrations than plants in reference site forests. The data provide evidence that riparian forest communities within agricultural environments absorb and retain nutrients lost from agricultural uplands. As such they are important components of agricultural ecosystems helping to maintain acceptable stream water quality. It is suggested that ecologically sound agricultural practice should include longterm maintenance of natural riparian vegetation zones within agricultural areas.
Traditional management of a hillside agroecosystem in Tlaxcala, Mexico: An ecologically based maintenance system
Authors: Mountjoy Daniel C. , Gliessman Stephen R. 
Published: October 2009

AbstractTraditional agricultural systems are increasingly being recognized as important examples of ecologically sustainable production methods and as such deserve agroecological attention. In a study of terrace agriculture in Tlaxcala, Mexico, the authors identify several management features which have been used for as long as three thousand years. The theoretical approach employs the notion of open versus closed agroecosystems for examining soil and water management, species diversity, and nutrient cycling. In the traditional system, conservation of existing resources is the distinctive feature whereas, with modern techniques, the emphasis is on replacement. The most distinctive feature of the Tlaxcalan agroecosystem is the terrace/cajete complex which serves to contain heavy downpours and trap eroded soil, ensures diversity of plant species, and traps and concentrates nutrients. The functioning of this traditional system is endangered by new management strategies that have responded to external political, economic and social pressures for change. This article discusses the ecological repercussions of these new practices and suggests ways that appropriate elements may be integrated to promote the sustainability of food production.