bluuebunny/crossref_metadata_2025_split huggingface dataset:
Using farmer knowledge to combat low productive spots in rice fields of a Sahelian irrigation scheme
Authors: van Asten P. J. A. , Barro S. E. , Wopereis M. C. S. , Defoer T. 
Published: June 2004

AbstractIn the oldest sections of Burkina Faso's largest irrigation scheme in the Sourou Valley (13° 10′ N, 03° 30′W) rice (Oryza sativa L.) yields dropped from about 5 to 6 t ha−1 in the early 1990s, shortly after establishment of the scheme, to 2 to 4 t ha−1 from 1995 onwards. Farmers blamed this yield decline on the appearance of 2 to 20 m diameter low productive spots. According to farmers and field measurements, the low productive spots decreased yields by 25–50 per cent. The low productive spots are caused by Zn deficiency. Low Zn availability is related to the very low DTPA‐extractable Zn content of the soil (0·08–0·46 mg kg−1), the alkaline‐calcareous character of the soil, the non‐application of Zn fertilizers, and a relatively large P fertilizer dose (21 kg P ha−1). Farmers were correct in relating the calcareous nature of the soil to the presence of the low productive spots. They were instrumental in identifying application of decomposed organic resources (e.g. rice straw at 5 t ha−1) as a short‐term solution that increases yields by 1·5 to 2·0 t ha−1. Application of Zn fertilizer (10 kg Zn ha−1) in 29 farmer fields in the 2001 dry season eradicated the low productive spots and increased yields from 3·4 to 6·0 t ha−1. Although application of Zn fertilizer is strongly recommended, it is not yet available in Burkina Faso. Based on a comparison of fertilizer prices on the world market and the local market, we expect that the use of Zn fertilizers will be highly profitable (cost/value ratio ≫ 2). Despite the relatively recent introduction of irrigated rice cropping, most farmers showed a good understanding of cropping constraints and possible solutions. Both farmers and researchers mutually benefited from each other's knowledge and observations. Copyright © 2004 John Wiley & Sons, Ltd.
Monitoring of soil erosion and assessment for contribution of sediments to rivers in a typical watershed of the Upper Yangtze River Basin
Authors: Fan J. R. , Zhang J. H. , Zhong X. H. , Liu S. Z. , Tao H. P. 
Published: June 2004

AbstractAn assessment of the effectiveness of soil conservation practices is very important for watershed management, but the measurement over a small area does not necessarily represent the truth over a large area. Monitoring of soil erosion and analysis of sediment delivery were carried out in the Lizixi watershed (which is typical of the Upper Yangtze Basin, China), using remote sensing and a geographic information system (GIS). Land‐use and land‐cover maps were prepared by an interpretation of 1986 and 1999 images from SPOT and Landsat TM. Slope‐gradient maps were created from digital elevation model (DEM), while merged images of SPOT and Landsat TM were used to obtain land‐use information. The area of soil erosion was classified by an integration of slope gradients, land‐use types and vegetation cover rates, and soil erosion rates and their changes were calculated in a grid‐based analysis using an Erdas GIS. The change in sediment delivery ratio was estimated based on the changes in soil erosion rates from both monitoring and the truth survey. There was a reduction in soil erosion rate of 4·22 per cent during a 13‐year period after soil conservation practices were adopted in the Lizixi watershed. The amount of sediments transported into rivers has decreased by 51·08 per cent during the same period due to an integrated application of biological and engineering measures. The comparison of soil erosion severity between pre‐conservation and post‐conservation revealed that soil loss has been obviously diminished and the measures were quite effective. Copyright © 2004 John Wiley & Sons, Ltd.
Determinants of farmers' willingness to pay for soil conservation practices in the southeastern highlands of Ethiopia
Authors: Asrat P. , Belay K. , Hamito D. 
Published: June 2004

AbstractThis paper examines the determinants of farmers' willingness to pay for soil conservation practices in the highlands of Bale, southeast Ethiopia. The paper is based on analysis of data collected from 100 randomly selected household heads. The study applied Contingent Valuation Method for the purpose of eliciting farmers' valuation of soil conservation practices in terms of both cash payment and labour contribution. The results reveal that farmers in the study area are less willing to pay cash for soil conservation measures. In terms of labour contribution, however, it was found that they are willing to spend a substantial amount of time per week. Results from logistic regression analysis show that farmers' decisions to participate in soil conservation practices are influenced by a host of factors. The implication is that taking these factors into account while planning soil conservation measures enables policy makers to come up with projects that win acceptance by the local people. Copyright © 2004 John Wiley & Sons, Ltd.
Comparison of litter decomposition in a natural versus coal‐slurry pond reclaimed as a wetland
Authors: Taylor J. , Middleton B.A. 
Published: June 2004

AbstractDecomposition is a key function in reclaimed wetlands, and changes in its rate have ramifications for organic‐matter accumulation, nutrient cycling, and production. The purpose of this study was to compare leaf litter decomposition rates in coal‐slurry ponds vs. natural wetlands on natural floodplain wetlands in Illinois, USA. The rate of decomposition was slower in the natural wetland vs. the coal pond (k = 0·0043 ± 0·0008 vs. 0·0066 ± 0·0011, respectively); the soil of the natural wetland was more acidic than the coal pond in this study (pH = 5·3 vs. 7·9, respectively). Similarly, higher organic matter levels were related to lower pH levels, and organic matter levels were seven‐times higher in the natural wetland than in the coal pond. The coal slurry pond was five years old at the time of the study, while the natural oxbow wetland was older (more than 550 years). The coal‐slurry pond was originally a floodplain wetland (slough); the downstream end was blocked with a stoplog structure and the oxbow filled with slurry. The pattern of decomposition for all species in the coal pond was the same as in the natural pond;Potomogeton nodosusdecomposed more quickly thanPhragmites australis, and both of these species decomposed more quickly than eitherTypha latifoliaorCyperus erythrorhizos(k = 0·0121±0·0008, 0·0051 ± 0·0006, 0·0024 ± 0·0001, 0·0024 ± 0·0004, respectively). Depending on how open or closed the system is to outside inputs, decomposition rate regulates other functions such as production, nutrient cycling, organic‐layer accumulation in the soil, and the timing and nature of delivery of detritus to the food chain. Copyright © 2004 John Wiley & Sons, Ltd.
Social resilience as a controlling influence on desertification in Senegal
Authors: Bradley D. , Grainger A. 
Published: June 2004

AbstractWhile ecological resilience may explain why apparent symptoms of desertification are often temporary, social resilience can prevent degradation resulting from overexploitation of land in response to drought and other constraints. This paper describes a Social Resilience Model in which actors switch from performance strategies to survival strategies when the perceived severity of constraints exceeds a critical performance–survival threshold (PST). This is determined in comparison with a reference mode that depends on a learning facility developed by repeated exposure to cycles of constraint, search and feedback. Actors select particular strategies by comparing welfare gains with their aspiration levels—a concept that allows more flexible decision making than profit maximizing or satisficing alone. The model is tested in the silvopastoral zone of Senegal, where desertification is not as widespread as commonly assumed, despite severe constraints. The two major ethnic groups, the Wolof (mainly croppers) and the Peul (mainly pastoralists) anticipate and respond to environmental and socio‐economic constraints differently, and have different performance and survival strategies. The Peul have the higher social resilience, with more flexible decision‐making objectives, greater mobility, a more extensive action space, a learning facility supporting efficient search and feedback processes, a reference mode attuned to high anticipation and recognition of stress, and a high PST. They also exhibit more continuous performance–survival switching than the Wolof, who make a radical change from cropping to labour migration and reliance on external support. Copyright © 2004 John Wiley & Sons, Ltd.
Front Cover: Macromol. Biosci. 6/2004
Authors: Brzezinska Krystyna R. , Deming Timothy J. 
Published: June 2004

Front Cover: The picture on the front cover shows the synthesis of poly(methyl acrylate)‐block‐poly(γ‐benzyl‐L‐glutamate) (PMA‐b‐PBLG) diblock copolymers, performed using atom transfer radical polymerization of methyl acrylate and living polymerization of γ‐benzyl‐L‐glutamate‐N‐carboxyanhydride (Glu‐NCA). Amido‐amidate nickelacycle end groups were incorporated onto amino‐terminated poly(methyl acrylates) (PMA‐NH2), and the resulting complexes were successfully used as macroinitiators for growth of polypeptide segments. This method allows the controlled preparation of polypeptide‐block‐poly(methyl acrylate) diblock architectures with control over polypeptide chain length and without formation of homopolypeptide contaminants.Further details can be found in the Communication by K. R. Brzezinska, T. J. Deming* on page 566.
Non‐Isothermal Crystallization Behavior of Poly(trimethylene terephthalate) Synthesized with Different Catalysts
Authors: Chen Kequan , Tang Xiaozhen , Shen Jie , Zhou Yan , Zhang Biao 
Published: June 2004

AbstractSummary: Non‐isothermal crystallization behavior of PTT resins synthesized with different catalysts was studied by using differential scanning calorimetry (DSC) and polarized light microscopy (PLM). The results showed that with the increase of the cooling rate, the crystallization temperature for poly(trimethylene terephthalate) (PTT) resin decreased, which indicated that the crystallization process was controlled by the nucleation. Catalyst had no effect on the crystallization development process, but had somewhat effect on the non‐isothermal crystallization mechanism. The average values of Avrami exponent, for PTT with different catalysts were between 3 and 4. It was assumed that the non‐isothermal crystallization mechanism for PTT with or without catalyst was the combination of homogenous and heterogeneous nucleation and spherulite growth, but it mainly depended on the latter. For sample 4, the non‐isothermal crystallization underwent secondary crystallization process when cooling rate was over 20 °C/min. At the same cooling rate, the crystallization temperature, the crystallization ability and the crystallization rate of PTT resins followed the sequence as: sample 2 > sample 1 ≈ sample 3 ≈ sample 4, which proved that catalysts could significantly prompt crystallization. The cooling rate had significant effect on the crystallization ability parameters of PTT, i.e., with the increase of cooling rate, the crystallization ability declined. Although catalyst could increase the crystallization ability of PTT, the effect was very limited because the effect of the molecular weight on the crystallization ability would be superior to the catalyst when the molecular weight of PTT was significantly high. The specific surface area of catalyst had also a great influence on the spherulitic morphology of PTT formed in the cooling process. The spherulite dimensions decrease with increasing the specific surface area of catalyst because of an increase in the nucleation rate, which produces more and smaller spherulites that can not grow larger before impinging on each other.
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Effects of amifostine on healing of microvascular anastomoses, flap survival, and nerve regeneration with preoperative or postoperative irradiation
Authors: Aydin Atakan , Özden Burcu Çelet , Mezdeği Ali , Kurul Sidika , Meral Rasim , Solakoğlu Seyhun 
Published: June 2004

AbstractAmifostine is an organic thiophosphate compound, which has both cytoprotective and radioprotective effects. An experimental study was undertaken to investigate the effects of its use on reconstructive surgery in cancer treatment. One hundred and twenty guinea pigs were divided into three equal groups to investigate flap survival and healing, patency of microvascular anastomoses, and nerve regeneration, respectively. The groups were subdivided in such a way that they were given either preoperative or postoperative radiotherapy, with or without amifostine treatment. Macroscopic and planimetric examination, light and electron microscopy, and histomorphometric analyses were performed to evaluate flap survival and healing, patency of arterial anastomoses, and nerve regeneration. Although flap survival rates were not affected, significantly better flap healing was observed in the postoperative radiotherapy subgroup with amifostine treatment. However, amifostine treatment did not result in a statistically significant difference in terms of anastomotic patency and nerve regeneration with either preoperative or postoperative radiotherapy. © 2004 Wiley‐Liss, Inc. Microsurgery 24:1–8 2004.
Myasthenia gravis and premature ovarian failure
Authors: Ryan Monique M. , Jones H. Royden 
Published: June 2004

AbstractWe describe a patient who developed seropositive myasthenia gravis 16 years after she was diagnosed with autoimmune premature ovarian failure with antibodies to the receptor for follicle‐stimulating hormone (FSH). Although thymectomy led to improvement of her myasthenic symptoms, menses did not resume. Such combined seropositivity for antibodies to acetylcholine and ovarian hormone receptors in a patient with myasthenia gravis and premature ovarian failure may reflect common disease mechanisms, although the precise pathogenesis of these disorders remains ill‐defined. Muscle Nerve 30: 231–233, 2004
Effect of size and pressure of surface recording electrodes on amplitude of sensory nerve action potentials
Authors: Ven Antoon A. , Van Hees Johan G. , Stappaerts Karel H. 
Published: June 2004

AbstractThe influence of electrode size on sensory nerve action potential (SNAP) amplitude of the lateral antebrachial cutaneous nerve (LACN) and sural nerve (SN) was studied in 63 healthy volunteers. The SNAP amplitudes were measured using surface recording electrodes of three different sizes, positioned across the nerve. Mean amplitudes using a 5‐mm electrode were 9.0% (SN) and 15.3% (LACN) higher than with a 20‐mm electrode and 19.4% (SN) and 25.8% (LACN) higher than using a 40‐mm electrode. To study the influence of pressure on surface recording electrodes, studies were performed on the LACN in 31 healthy volunteers. Light pressure of the recording electrodes on the skin gave lower amplitudes (15.3%) than did greater pressure or pressure applied between active and reference electrodes. These studies demonstrate that standardized surface recording electrode size and pressure are imperative for obtaining valid and reliable results in experimental studies or in clinical follow‐up of patients undergoing nerve conduction studies. Muscle Nerve 30: 234–238, 2004
Chronic inflammatory demyelinating polyradiculoneuropathy in patients with liver transplantation
Authors: Echaniz‐Laguna Andoni , Battaglia Fabrice , Ellero Bernard , Mohr Michel , Jaeck Daniel 
Published: June 2004

AbstractWe report two patients with orthotopic liver transplantation (OLT) who developed a syndrome that fulfilled criteria for definite chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). One patient had OLT because of alcoholic cirrhosis and one following hepatitis C–induced hepatic failure. Both had immunosuppressive therapy, with cyclosporine and prednisolone in one case and tacrolimus in the other case. Treatment with intravenous immune globulin (IVIG) significantly improved the neuropathy in both patients. In patients with OLT developing disabling sensorimotor neuropathies, CIDP should be considered as should the use of potentially beneficial immunosuppressive treatment. Muscle Nerve 30: 501–504, 2004
Phenotypic variability associated with Arg26Gln mutation in caveolin3
Authors: Fee Dominic B. , So Yuen T. , Barraza Carlos , Figueroa Karla P. , Pulst Stefan‐M. 
Published: June 2004

AbstractCaveolin3 (CAV3) is a protein associated with dystrophin, dystrophin‐associated glycoproteins, and dysferlin. Mutations in the CAV3 gene result in certain autosomal‐dominant inherited diseases, namely, rippling muscle disease (RMD), limb‐girdle muscular dystrophy type 1C (LGMD1C), distal myopathy, and hyperCKemia. In this report we show that a previously reported family with RMD has a mutation in the CAV3 gene. Affected individuals had either a characteristic RMD phenotype, a combination of RMD and LGMD1C phenotypes, or a LGMD1C phenotype, but one mutation carrier was asymptomatic at age 86 years. This phenotypic variability associated with mutations in CAV3 has been reported previously but only in a few families. It is important to remember the significant phenotypic variability associated with CAV3 mutations when counseling families with these mutations. These observations also suggest the presence of factors independent of the CAV3 gene locus that modify phenotype. Muscle Nerve 30: 375–378, 2004
Clinical, electrodiagnostic, and sonographic studies in ulnar neuropathy at the elbow
Authors: Beekman Roy , Van Der Plas Jeroen P. L. , Uitdehaag Bernard M. J. , Schellens Ronald L. L. A. , Visser Leo H. 
Published: June 2004

AbstractThe aim of this study was to determine possible correlations between the clinical characteristics, electrophysiological features, and sonographic ulnar‐nerve diameter in patients with ulnar neuropathy at the elbow (UNE). We prospectively performed clinical, electrodiagnostic, and sonographic studies in 102 patients having either purely sensory signs (35%) or sensorimotor signs (65%) of UNE. Nerve conduction studies had a sensitivity of 78%, and the addition of sonography increased this to 98%. The diagnostic value of both tests was not different among cases with and without motor deficit. Motor studies with recording from the abductor digiti minimi and first dorsal interosseous muscles were equally sensitive for the detection of conduction block or velocity slowing across the elbow, but the combination yielded more positive cases than when only one study was performed. There were modest negative correlations between the electrodiagnostic parameters and the sonographic ulnar‐nerve diameter. Electrodiagnostically and sonographically, there were no significant differences between clinically pure sensory and mixed sensorimotor cases of UNE, except for electrodiagnostic findings suggesting loss of motor axons in cases with motor signs. Almost half the patients with only sensory signs had electromyographic evidence of motor axonal loss. We conclude that, although UNE is clinically heterogeneous, the electrophysiological and sonographic findings are fairly consistent despite the clinical manifestations. Muscle Nerve 30: 202–208, 2004
Modeling and analysis of flexible queueing systems
Authors: Gurumurthi Suri , Benjaafar Saif 
Published: June 2004

AbstractWe consider queueing systems with multiple classes of customers and heterogeneous servers where customers have the flexibility of being processed by more than one server and servers possess the capability of processing more than one customer class. We provide a unified framework for the modeling and analysis of these systems under arbitrary customer and server flexibility and for a rich set of control policies that includes customer/server‐specific priority schemes for server and customer selection. We use our models to generate several insights into the effect of system configuration and control policies. In particular, we examine the relationship between flexibility, control policies and throughput under varying assumptions for system parameters. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004
Cellular bases of activity‐dependent paralysis in Drosophila stress‐sensitive mutants
Authors: Trotta Nick , Rodesch Chris K. , Fergestad Tim , Broadie Kendal 
Published: June 2004

AbstractStress‐sensitive mutants in Drosophila have been shown to exhibit activity‐dependent defects in neurotransmission. Using the neuromuscular junction (NMJ), this study investigates synaptic function more specifically in two stress‐sensitive mutants: stress‐sensitive B (sesB), which encodes a mitochondrial ADP/ATP translocase (ANT); and Atpα2206, a conditional mutant of the Na+/K+ ATPase α‐subunit. Mechanical shock induces a period of brief paralysis in both homozygous and double heterozygous mutants, but further analysis revealed distinct activity‐dependent neurotransmission lesions in each mutant. Basal neurotransmission appeared similar to wild‐type controls in both mutants under low frequency stimulation. High frequency stimulation, however, caused pronounced synaptic fatigue as well as slow and incomplete synaptic recovery in sesB mutants while Atpα2206 mutants displayed an increase (25‐fold) in synaptic failures. Perhaps to compensate for these activity dependent defects, the neuromuscular synapse was found to be overgrown in both mutants. Passive electrotonic stimulation, which initiates synaptic transmission independent of action potentials, ameliorated synaptic failures and resulted in increased neurotransmission amplitude in Atpα2206 mutants. In addition, spontaneous synaptic vesicle fusion rates were increased in Atpα2206 mutants, suggesting that, in the absence of action potential requirements, these synaptic terminals are healthy, if not hyperactive. Dye labeling studies revealed aberrant synaptic vesicle cycling in sesB mutants indicating a reduction of functional synaptic vesicles. We therefore postulate that both stress‐sensitive mutants harbor unique neurotransmission defects: Atpα2206 mutants are unable to maintain ionic gradients required during repetitive action potential propagation, and sesB mutants cannot maintain synaptic vesicle cycling during periods of high demand. © 2004 Wiley Periodicals, Inc. J Neurobiol 60:328–347, 2004
Exogenous testosterone prevents motoneuron atrophy induced by contralateral motoneuron depletion
Authors: Fargo Keith N. , Sengelaub Dale R. 
Published: June 2004

AbstractGonadal steroids exhibit neuroprotective and neurotherapeutic effects. The lumbar spinal cord of male rats contains a highly androgen‐sensitive population of motoneurons, the spinal nucleus of the bulbocavernosus (SNB), whose morphology and function are dependent on testosterone in adulthood. Unilateral SNB motoneuron depletion induces dendritic atrophy in contralateral SNB motoneurons, but this atrophy is reversed in previously castrated males treated with testosterone. In the present experiment we test the hypothesis that the morphology of SNB motoneurons is protected from atrophy after contralateral motoneuron depletion by exogenous testosterone alone (i.e., with no delay between castration and testosterone replacement). We unilaterally depleted SNB motoneurons by intramuscular injection of cholera toxin conjugated saporin. Simultaneously, some saporin‐injected rats were castrated and immediately given replacement testosterone. Four weeks later, contralateral SNB motoneurons were labeled with cholera toxin conjugated HRP, soma sizes were measured, and dendritic arbors were reconstructed. Contralateral SNB motoneuron depletion induced somal atrophy and dendritic retraction, but testosterone treatment prevented both of these effects. Thus, the presence of high‐normal levels of testosterone prevents motoneuron atrophy induced by contralateral motoneuron depletion. These data support a therapeutic role for testosterone in preventing atrophy induced by motoneuron injury. © 2004 Wiley Periodicals, Inc. J Neurobiol 60:348–359, 2004