bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prognostic significance of lymph node metastasis and surgical margin status for distal cholangiocarcinoma
Authors: Murakami Yoshiaki , Uemura Kenichiro , Hayashidani Yasuo , Sudo Takeshi , Hashimoto Yasushi , Ohge Hiroki , Sueda Taijiro 
Published: February 2007

AbstractBackground and ObjectivesPrognostic indicators for patients with distal cholangiocarcinoma have not been confirmed because of its rarity. The aim of this study was to identify useful prognostic factors in patients undergoing surgical resection for distal cholangiocarcinoma.MethodsCharts of 43 patients with distal cholangiocarcinoma who underwent surgical resection were retrospectively reviewed. Pancreatoduodenectomy was performed in 35 patients, and segmental bile duct resection in 8. Potential clinicopathological prognostic factors were examined by univariate and multivariate survival analysis.ResultsPostoperative complications occurred after surgery in 19 patients (44%), but there was no mortality. Overall survival rates were 72%, 53%, and 44% for 1, 3, and 5 years, respectively (median survival time, 26.0 months). Univariate analysis found that older age, pathological pancreatic invasion, lymph node metastasis, perineural invasion, positive surgical margin, and TNM stages II and III were significant predictors of poor prognosis (P < 0.05). Furthermore, lymph node metastasis and positive surgical margin were found to be significant independent predictors of poor prognosis with a Cox proportional hazards regression model (P < 0.05).ConclusionsThese results suggest that lymph node metastasis and positive surgical margin as determined by surgical resection might be useful in predicting post‐surgical outcome in patients with distal cholangiocarcinoma. J. Surg. Oncol. 2007;95:207–212. © 2007 Wiley‐Liss, Inc.
The effect of seasonal flooding on the clay mineralogy of a soil series in the Volta Lake drawdown area, Ghana
Authors: Amatekpor J. K. 
Published: February 2007

AbstractFour pedons of Arenic/Grossarenic Paleustalf (Denteso Series), in the Volta Lake drawdown area in Northern Ghana, were described and sampled just before seasonal floodings commenced in the area. After 5 years of periodic flooding the soils were re‐examined and sampled. Soil properties required for soil classification, including the clay mineralogy, of both the pre‐flooding and the post‐flooding samples were determined. One of the main objectives was to identify changes in soil properties which result from the periodic flooding.X‐ray diffraction (XRD) indicated that before flooding the main clay minerals of the Denteso were kaolinite and smectite, and there were also some mica and quartz in the total clay fraction. Comparison of the pre‐flooding with the post‐flooding data revealed that practically all the smectite disappeared from all the three sampled pedons that were flooded for 5 to 20 weeks during each flood cycle, while the smectite persisted in the non‐flooded pedon. With the disappearance of the 2 : 1 lattice clays there occurred a considerable decrease in cation exchange capacity (CEC) and in base saturation of the flooded pedons ranging from 0.04 to 3.63 cmol kg −1. Also, there was an increase in pH by 0.4 to 1 unit in most horizons of the flooded pedons in spite of the general decrease in base saturation. These changes in CEC, base saturation and pH support the XRD evidence that the seasonal floodings caused pedochemical weathering of the smectite in this loamy sand soil at a very fast rate during the 5 year period and this had resulted in the lowering of the buffering capacity and a general impoverishment of the soil series.
Land degradation, stocking rates and conservation policies in the communal rangelands of Botswana and Zimbabwe
Authors: Abel N. O. J. , Blaikie P. M. 
Published: February 2007

AbstractCommunal rangeland management policies in Botswana and Zimbabwe are based on incorrect technical assumptions about the stability of semiarid rangeland, the nature of rangeland degradation, and the benefits of destocking. Consequently, inappropriate policies, stressing the need to destock and stabilise the rangelands, are pursued. Acknowledgement of the great instability but intrinsic resilience of rangeland would encourage the Governments to more favourably regard the opportunistic stocking strategies of the agro‐pastoralists of the Communal Areas. However, degradation of rangelands is occurring, although at varying rates. This justifies the promotion of a ‘tracking strategy’, in which livestock densities are encouraged to follow, more closely that at present, variations in rainfall.The establishment of grazing territories controlled by specific ‘communities’ may be a prerequisite for the promotion of the tracking strategy, and for communal rangeland management and improvement. However, the establishment of such territories must take into account social equity, institutional problems and transaction costs, as well as spatial and temporal variation in rangeland resources.
Modelling soil organic matter decomposition and rainfall erosion in two tropical soils after forest clearing for permanent agriculture
Authors: Bouwman A. F. 
Published: February 2007

AbstractA soil organic matter turnover model has been developed to analyse soil carbon (soil organic‐C) loss caused by organic matter decomposition and rainfall erosion in soils used for permanent cultivation. It has been used to build up model profiles of five soils, one occurring in temperate and four in tropical regions, on the basis of estimates for ‘natural’ organic matter input. Organic matter input data for different systems of cultivation were used to model the long‐term decomposition of soil organic‐C in these model profiles. The modelling results show that soil organic matter decomposition in the tropics is three to four times faster than in temperate regions, and that there is a marked influence of soil type and soil climate. Simulated losses of organic‐C in the tropical soils, not accounting for erosion are 31 to 50 per cent after 50 years and 43 to 63 per cent after 100 years of continuous cultivation. The simulated loss of soil organic‐C when rainfall erosion is also allowed for is 40 to 80 per cent. Erosion caused an extra loss of at least 7 per cent after 100 years. The initial input of charcoal from forest burning is lost through erosion at a rate of 50 to almost 100 per cent, depending on the severity of erosion. The sensitivity of modelling results to variations in input data was also analysed. The losses of soil carbon were also used to calculate the global flux of CO2 from soils. Soils are probably a small but not negligible source of CO2.
Quantification of accelerated soil erosion using the environmental tracer caesium‐137
Authors: Sutherland R. A. 
Published: February 2007

AbstractThe principal objective of this investigation was to quantify erosion rates for five agricultural fields in three separate study areas in Saskatchewan. The radionuclide tracer caesium‐137 (137Cs) was used to quantify net erosion and net deposition within the landscape over a 30‐year period. Uneroded (native) sites were used to establish the mean background level of 137Cs in each of the study areas. The assumption being that agricultural sites with 137Cs areal activities greater than the native site were subject to deposition, and sites with 137Cs less than the native control site were subject to erosion. A linear proportionality model was used to convert the loss or gain of 137Cs to net soil erosion or deposition. Results have indicated that accelerated (anthropogenic) erosion has been commonplace on arable land in Saskatchewan, even on near‐level fields (< 1.3 degrees). The net integrated sediment output from the five agricultural fields ranged from — 0.6 t th−1 y−1 to — 6.8 t ha−1 y−1 (where negative values represent erosion). What is more alarming is that between 40 and 75 per cent of all sites sampled within individual fields had erosion rates in excess of the generally accepted rate of soil formation (1.0 t ha−1 y−1). Also, in one highly eroded field (Crystal Springs medium sloping site) 65 per cent of the sites sampled exceeded the upper tolerable erosion rate of 11.0 t ha−1 y−1. These results indicate significant degradation of the non‐renewable soil resource has occurred over the past 30 years and is still presently active. Land degradation by accelerated erosion would result in reductions in effective rooting depth, soil moisture holding capacity, essential nutrient stores, and would adversely effect the physical structure of the topsoil. The major reason for accelerated erosion on arable land in Saskatchewan is the practice of summer fallowing, where the field is left in a ‘bare’ state and repeatedly tilled every second or third year. During a fallow period, or prior to crop emergence during a cropping year, fields are subject to wind and water erosion. On near‐level fields wind would be the dominant transport agent, while on sloping fields inter‐rill and rill erosion would be the primary forces of erosion. It is suggested that the appropriate conservation farming response would be to increase application of surface mulches and possibly to decrease the frequency of summer fallowing. Without such efforts long‐term sustainable agricultural production in the Prairies of Canada is considered to be a tenuous land use practice.
Development paths for rural areas in the european community
Authors: Conrad Jobst 
Published: February 2007

AbstractBased on the findings from the research project: ‘Alternative Uses for Land and the New Farmworker—Segregation versus Integration’, this paper analyses broad lines of development and available options for rural areas in the European Community. Taking into account various limitations on agricultural, forestry, and nature conservation activities, the emergence of three agro‐structural regional types is likely to occur:

—rural areas with intensive agriculture;
—rural areas constituting mainly agrarian‐touristic peripheries, which exploit their endogenous development potentials on the basis of quasi‐tourism
—less‐favoured areas with a tendency towards depopulation, which may serve as ecological balance areas.
Preliminary evaluation of pineapple mixed‐cropping systems for protecting reclaimed gulleys in the tropics: An experiment in Southeast Nigeria
Authors: Asoegwu S. N. , Obiefuna J. C. 
Published: February 2007

AbstractThis paper reports on research into the effectiveness of pineapple monocropping or intercropping systems (with cowpeas or egusi‐melon) for reestablishing vegetative cover to check soil erosion on a reclaimed gulley in the tropical rainforest of southeastern Nigeria.High‐density pineapple planting, intercropped with egusi‐melon, was found to promote rapid vegetative cover, checked soil loss, improved soil structural stability and produced a high crop yield. Soil loss was moderate in pineapple plots intercropped with cowpeas and least in pineapple plots intercropped with egusi‐melon. Increasing pineapple density enhanced the field establishment of cowpea and egusi‐melon respectively.
Avoidance of degradation of alpine pasture through grazing management: Investigations of change in vegetation nutrition characteristics as a consequence of sheep grazing at different periods of the growing season
Authors: Andrighetto I. , Cozzi G. , Zancan M. , Berzaghi P. 
Published: February 2007

AbstractThe maintenance of animal husbandry in mountain areas can prevent the general degradation of the landscape due to the disuse of pastures and meadows. This study investigated the changes over the productive season of the nutritional characteristics of an Alpine pasture with the objective of maintaining grazing sheep fed only on the available herbage.Four homogeneous areas of an Alpine pasture located in northeast Italy were cut at the end of June, July, August, and September, simulating different grazing periods by the animals. the herbage was sampled to estimate the botanical and chemical composition and fed to four Lamon breed wethers (76‐5 kg average bodyweight) measuring voluntary intake, digestibility and energy value. the botanical composition of the pasture changed as the vegetative season advanced, with a progressive increase in grass species. the protein content decreased from 16‐3 per cent dry matter in the first grazing period, to 9‐6, 9‐9 and 7‐9 per cent, respectively, in the following, while the neutral detergent fibre increased from 62‐1 per cent in the first period to 78‐4, 77‐7 and 79‐4 per cent in July, August, and September, respectively.The nutritional evaluation of the forage material was carried out using four Lamon wethers housed in single metabolic cages. the voluntary intake of herbage was 1151 g d−1 at the end of June, decreasing significantly to values below the recommended requirement for maintenance in the subsequent periods of the study. No selectivity was observed for specific botanical species. the in vivo digestibility of the herbage was lowered by the delay in the use of the pasture and the resulting energy intake met the recommended maintenance requirements for grazing only in the earlier period of pasture consumption. the late use of the pasture and the corresponding underfeeding of the animals would necessitate a feed supplementation to limit excessive loss of bodyweight. the conclusion is that the objective of maintaining grazing animals in mountain areas without any supplementation can be carried out exclusively by adopting an efficient grazing management able to provide good quality pasture throughout the vegetative season.
Environmental consequences of land degradation in coastal drainage basins of north Queensland, Australia: Influence of farming practices
Authors: Arakel A. V. , Loder T. , McConchie D. , Pailles C. 
Published: February 2007

AbstractViews expressed by sugar cane farmers in the Johnstone Rivers system, north Queensland, are consistent with the broader community concern about the potentially adverse ecological effects of point source discharges to the Great Barrier Reef lagoon. the main link between agricultural land use and the deterioration of surface and groundwater quality in the region is perceived by the farmers to be a consequence of the influence exerted by new farm management strategies and economic constraints on local environmental variables, particularly soils. the effectiveness of the land use practices in relation to land capability and productivity thresholds is considered by farmers to be essential for developing new farm management strategies and for improving water quality in the north Queensland coastal regions. as a result of increasing inhomogeneity of land use practices involving the application of chemicals, catchment based investigation, including systematic interviews with the land users, is needed for the development of reliable databases on problems related to the discharge of agricultural chemicals to coastal waters.
Potential chemical time bombs in the schelde estuary
Authors: Van Eck G. T. M. , De Rooij N. M. 
Published: February 2007

AbstractThe Schelde estuary is heavily polluted with many different (micro)pollutants. This results in high concentrations in the abiotic and biotic compartments of the Schelde estuary and in various effects. the present day suboxic and anoxic conditions in the upper estuary are probably responsible for the high distribution coefficients for some trace metals in the lower Schelde estuary (Western Schelde). a future reduction in discharges with a high biological oxygen demand will therefore not only result in higher oxygen concentrations, but probably also in lower distribution coefficients for trace metals in the Western Schelde. Simulations show that lower trace metal distribution coefficients will probably result in higher concentrations of dissolved (bioavailable) trace metals, even with substantially reduced discharge rates, due to the desorption of trace metals from resuspended bottom sediments.
Dyke‐protected floodplains: A possible chemical time bomb?
Authors: Japenga J. , Salomons W. 
Published: February 2007

AbstractFor more than a century contaminated sediment has been deposited on the Rhine floodplains. Freshly deposited sediment samples from the regularly flooded dyke‐protected floodplain were obtained in 1958, 1970, 1972, 1981 and 1988. Heavy metals and arsenic as well as chemically persistent organic micropollutants [polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB) and DDT derivatives] were determined in the air‐dried samples stored in a specimen bank. Pollutant levels showed a tendency to decrease; for PCBs and HCB the highest levels were present in the 1970s. Concentrations exceed natural background levels and in some instances are well above alarm levels established for the Netherlands. Although a decrease has been seen in the average annual input of pollutants onto the floodplain, accumulation in the upper layer of the floodplain sediments continues. as a consequence of the general chemical characteristics of the sediment (high organic matter, calcium carbonate and clay contents) the pollutants remain tightly bound to the sediment particles. as the pollutant levels are high, changes which reduce the organic matter and calcium carbonate contents May, cause severe environmental problems: enhanced bioavailability and leaching of pollutants May, result from the increased solubilization of pollutants.
Local faces, global flows: The role of land use and land cover in global environmental change
Authors: Turner B. L. 
Published: February 2007

AbstractThe emergence of land‐use and land‐cover change (LUCC) as one of the major themes within the global environmental change research community poses a series of difficult but not insurmountable problems. LUCC takes place incrementally through the operation of sets of human and biophysical forces largely specific to the locale in question, but cumulatively LUCC contributes significantly to global environmental change. Linking LUCC to global change requires the cooperation of the natural and social sciences to bridge the local to global dynamics involved. The International Geosphere‐Biosphere Programme and the Human Dimensions of Global Environmental Change Programme are undertaking the development of an international research project with such aims in mind. This project seeks to improve understanding of LUCC dynamics by balancing the need for a nuanced understanding at the local level with the need from improved regional and global LUCC models. The rudiments of this effort and some of problems confronting it are outlined here.
Future of land use in Australia: An economic perspective
Authors: Mues C. , Peterson D. , Walshaw T. , Morris P. 
Published: February 2007

AbstractIt is proposed that the standard economist's model of optimum land use is extended to include the interaction with land cover and land condition. Such a model allows consideration of the influence of market factors and government policies and programmes on land use patterns and management practices, and the feedback effect on land cover and land condition. Recent developments in the approach to modelling land condition, which include the joint consideration of economic factors and physical processes, are discussed. Factors affecting the pattern of agricultural land use in Australia are then reviewed. The importance of considering economic and physical interactions when assessing land use patterns is increasingly being recognized in research and policy development. If research is to meet the needs of land managers in the future then economists and physical scientists will need to integrate their data modelling capabilities in order to address natural resource management issues.
Contribution of ‘sustainability’ criteria to social perceptions of land use options
Authors: Cocks K. D. , Walker B. H. 
Published: February 2007

AbstractWith relatively minor exceptions, the process of land use change is one of intensification and the narrowing of future land use options. This has led to community concern for the gradual irrecoverable loss of values associated with less intensive land uses; in particular, concern for the availability and functional capacity of biodiversity, earth materials, water and air. Concern extends to the functionality of these resources in industrial, amenity and service roles.Such losses, called, inter alia, environmental costs, are never wholly avoidable despite the hopes behind the sustainable development concept. What is realistically possible is conservative development, meaning that land uses with environmental costs exceeding the economic net benefits would be proscribed as options, through the application of extant and emerging social technologies such as land use zoning, environmental standards and environmental impact assessment.This paper presents some general and some more specific ideas about land uses susceptible to proscription under the conservative development criterion. Most major land uses stand to be challenged to a degree, particularly in densely populated areas, regions of economic opportunity and/or in regions recognized as having a high conservation value. Proposals involving a leap in intensification or loss of remnant or old‐established land uses will be more liable to assessment for proscription. Several regions are identified where joint assessment for exclusion across members of a suite of land uses would not be surprising (e.g. the Kimberleys); also some regions and situations where particular land uses stand to be challenged, e.g. irrigated cotton, high country developments and integrated forest harvesting.Rather than list intensification trends at length and predict which challenges to intensification might succeed, this paper discusses the prospects for development of social technologies which evaluate community concerns about the environmental costs of land use intensification. It is suggested that a blending of the existing procedures of the Resource Assessment Commission for regional resource inventory and evaluation and the existing resource allocation procedures of the Great Barrier Reef Marine Park Authority would form a highly defensible core for a new generation of option‐defining technologies. The social importance of having a rich suite of social technologies for addressing intensification issues is emphasized.
Study of salinity and waterlogging in Uttar Pradesh (India) using remote sensing data
Authors: Dwivedi R. S. 
Published: February 2007

AbstractSalinization/alkalization and waterlogging have rendered a sizeable area of India's arable lands unproductive. These highly dynamic phenomena can be studied using remote sensing data collected at regular intervals. Landsat Multi‐spectral Scanner data of 28 February 1975 and 9 March 1990 were interpreted visually to derive information about the spatial extent and distribution of salt‐affected soils. A significant decrease in the area of salt‐affected soils was noted over this period, which can be attributed to reclamation efforts by government agencies and farmers. On a large scale, i.e. 1:50000, the waterlogged area could also be mapped using a Landsat Thematic Mapper false‐colour composite print.
The effect of leaching and irrigation on the growth of Atriplex semibaccata
Authors: De Villiers A. J. , Van Rooyen M. W. , Theron G. K. , Claassens A. S. 
Published: February 2007

AbstractMining activities along the west coast of South Africa will lead to salinization of the soil if sea‐water is used in the mining process. Laboratory studies were conducted to determine the influence of leaching depth and the amount and frequency of irrigation on the growth of Atriplex semibaccata R. Br. Leaching depth as well as the amount and frequency of irrigation had no significant effect on biomass production. However, the interaction between leaching depth and amount of irrigation did influence the biomass production of Atriplex semibaccata. Root:shoot ratio increased as the amount of irrigation decreased.