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This paper explores the challenge of defining the scope of a systems model, emphasising three aspects: boundary, granularity and conceptual scope. The significance of these is illustrated by reference to a model of land-use decisions made in villages bordering on the Mafungautsi forest in Zimbabwe. The purpose of this model was to help policy players (Forestry Commission staff, non-governmental organisations, researchers and local people) to understand the impact of policy interventions on local people’s livelihoods. Scoping decisions that were made in building the Mafungautsi model were deliberately liberal, to encompass the interests of all participants in the modelling process. These decisions now present a range of serious challenges: the difficulty of model calibration, the computational expense of running simulations, and the difficulty for new users to understand the model. Facilitators of modelling teams need to consider the serious implications of giving everyone what they want and including all participants’ ideas in a model. In the long run, it may be better to be tough and reject many suggestions at the outset. The former approach is unlikely to lead to a tractable model, while the latter may ultimately offer greater satisfaction for all. We are grateful to the UK’s Department for International Development (DFID) and the European Community for financial support of this project. Thanks also to all of the ACM team who have contributed ideas on the process and content of the modelling work and who make it fun to undertake collaborative research. Thanks also to the participants in the Zimbabwe FLAC workshops for their input into the specification of the Mafungautsi model. Finally thanks to Robert Muetzelfeldt, Jasper Taylor, Jonathan Massheder, Fergus Sinclair and Jerry Vanclay for helping us to ride on the FLORES bandwagon.  相似文献   
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In the catfish Heteropneustes fossilis, the anterior kidney is a hemopoietic tissue which surrounds the adrenal homologues, interrenal (IR) and chromaffin tissues corresponding to the adrenal cortical and adrenal medulla of higher mammals. The IR tissue is arranged in cell cords around the posterior cardinal vein (PCV) and its tributaries and secretes corticosteroids. The chromaffin tissue is scattered singly or in nests of one or more cells around the epithelial lining of the PCV or blood capillaries within the IR tissue. They are ferric ferricyanide-positive. Leukemia-inhibitory factor (LIF)-like reactivity was noticed in the lining of the epithelium of the IR cell cords and around the wall of the PCV and blood capillaries. No staining was observed in the hemopoietic cells. IL-1β- and TNF-α-like immunoreactivity was seen in certain cells in the hemopoietic tissue but not in the IR region. Macrophages were identified with mammalian macrophage-specific MAC387 antibodies and are present in the hemopoietic mass but not in the IR tissue. Pigments accumulate in the hemopoietic mass as melano-macrophage centers (MMCs) and are PAS-, Schmorl’s- and Perls’-positive. The pigments contain melanin (black), hemosiderin (blue) and lipofuscin/ceroid (oxidized lipid, yellowish tan), as evident from the Perls’ reaction. The MMCs were TUNEL-positive as evident from FITC fluorescence, indicating their apoptotic nature. The MMCs showed significant seasonal variation with their density increasing to the peak in the postspawning phase. Melanins were characterized spectrophotometrically for the first time in fish anterior kidney. The predominant form is pheomelanin (PM), followed by eumelanin (EM) and alkali-soluble melanin (ASM). Melanins showed significant seasonal variations with the level low in the resting phase and increasing to the peak in the postspawning phase. Under in vitro conditions, lipopolysaccharide (10 µg/mL) treatment increased significantly the levels of PM and EM levels both at 16 and at 32 h and the ASM level at 32 h. On the other hand, the synthetic glucocorticoid dexamethasone (100 nM) decreased significantly the levels of EM, PM and ASM time-dependently. The results indicate that the anterior kidney is an important site of immune–endocrine interaction.  相似文献   
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Objective – Describe clinical characteristics and outcomes associated with canine patients undergoing surgical intervention for treatment of acute pancreatitis.
Design – Retrospective outcome study from 2001 to 2007.
Animals – Thirty-seven dogs.
Interventions – None.
Measurements and Main Results – The following data were collected for dogs who underwent surgical intervention in the course of treatment for severe acute pancreatitis: preoperative clinicopathologic and physical data, ultrasonographic findings, surgical procedure detail, histopathologic findings, and transfusion requirements. The survival rate was 80.8% in dogs with extrahepatic biliary obstruction, 64.3% in dogs undergoing necrosectomy, and 40.6% with pancreatic abscess. Overall survival was 63.6%. Surgical complications included intraoperative and postoperative hemorrhage in 12 dogs, postoperative development of diabetes mellitus in 3 dogs, exocrine pancreatic insufficiency in 1 dog, and bacterial peritonitis in 2 dogs.
Conclusion – Surgical intervention and aggressive postoperative care may be pursued in select dogs with severe acute pancreatitis. In dogs with extrahepatic biliary obstruction secondary to acute pancreatitis, surgical intervention may be associated with a good prognosis whereas dogs with pancreatic abscess formation may have a more guarded prognosis.  相似文献   
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The effects of nutritional treatments and the flowering promoter Paclobutrazol™ on tree growth and fertility were studied in unpedigreed seedling seed orchards (SSOs) of Eucalyptus camaldulensis and E. tereticornis at two locations in southern India. At Pudukkottai, a semi-arid site in Tamil Nadu State, five treatments were applied: (1) untreated control, (2) nitrogen (two doses of urea at 217 g N/tree), (3) nitrogen plus phosphorus (two doses of 312 g single superphosphate), potassium (two doses of 83 g muriate of potash) and trace elements (two doses of 10 g sodium borate and 25 g zinc sulphate), (4) pollarding trees at 4 m height with application of N, P, K and trace elements, (5) drenching with the flowering promoter Paclobutrazol (0.25 ml active ingredient per cm of stem girth) along with N, P, K and trace elements. At Panampalli, a higher-rainfall site in Kerala State, only treatments 1, 2 and 3 were applied. Four replicates of treatment plots sized 18 m × 18 m, with 22–32 trees per plot were set up in each orchard in randomized complete block designs. Untreated plots of E. camaldulensis and E. tereticornis at Pudukkottai displayed 12 and 21% fertile trees, respectively, in the first year of monitoring, while at Panampally the percentage of fertile trees in untreated E. camaldulensis plots was higher at 72%, and that of E. tereticornis similar at 23%. Both species attained greater stem diameter at breast height at age 9 years at the higher-rainfall location but there was no significant impact of fertilizer application on 9-year diameter at either site. Diameter was reduced by pollarding and Paclobutrazol application at Pudukkottai. Only Paclobutrazol produced a significant increase in fertility in both species for four successive years, increasing the percentage of fertile trees to 59 and 71%, respectively, for E. camaldulensis and E. tereticornis 1 year after application. The number of capsules produced per tree also increased significantly with Paclobutrazol application, although the difference was comparatively less by the fourth year. The number of capsules per umbel did not differ significantly between locations, whereas the germination rate varied between treatments although no consistent trends were observed.  相似文献   
37.
Stem water-soluble carbohydrates (WSCs) are important plant traits influencing grain yields in wheat. However, the traits regulating WSCs storage, particularly under different nitrogen (N) levels are poorly addressed. This study investigated 35 morpho-physiological traits associated with the variation in WSC concentration (WSCc) in the main stem of eight wheat genotypes including two primitive genotypes under three N levels (0, 100, and 200 kg N ha−1). 28 traits were significantly, positively or negatively, correlated with the WSCc in all N levels, and 22 of them were consistent across N levels. Majority of the traits were positively correlated with WSCc suggesting that multiple traits regulate WSCc in wheat plants. However, few traits such as root:shoot ratio (RSR), stem nitrogen (SN), leaf nitrogen (LN), nitrogen per unit leaf area (NLA), total vegetative mass (VMASS), cellulose (CL), and hemicellulose (HC), were negatively correlated with WSCc. This suggests that plant N concentration was an important selective force driving WSCc in wheat. Indeed, a percent increase in leaf N concentration resulted in 28% lower WSCc. Direct selection estimated that higher VMASS, flag-leaf width (FLW), but lower RSR was adaptive and resulted in higher WSCc in low N level. In contrast, lower VMASS and FLW were adaptive and resulted in higher WSCc in high N level. Higher cellulose and hemicellulose were associated with lower WSCc suggesting that a reduced carbon flux to stem structural compounds may improve WSCc in wheat plants. Together, these results demonstrate that a specific suit of trait changes that evolve under N-specific selection increase main stem WSCc but the adaptive value of these changes varies among traits and N levels.  相似文献   
38.
In India, many of the fish farmers stock 1-year-old stunted fishes (stunted yearlings) of Indian major carps (IMC) for enhancing fish production through compensatory growth, but many of them observed problems of early maturation in these fishes. Application of aromatase inhibitors for deceleration of ovarian maturation is one of the probable solutions to mitigate this issue. In the present study, a synthetic aromatase inhibitor letrozole [25 (L25) and 50 (L50) mg kg?1 feed] and a plant-derived aromatase inhibitor, grape seed extract [100 (G100) and 200 (G200) mg kg?1 feed], were fed to stunted yearlings of rohu (Labeo rohita) for 45 days well before the onset of breeding season. Maturation indices such as gonadosomatic index (GSI) and serum oestradiol (E) levels indicated a dose-dependent inhibition of ovarian development in the aromatase-inhibitor-treated fish. Higher dose of letrozole (GSI, 15.12 ± 0.18; E, 3.19 ± 0.42) and grape seed extract (GSI, 16.90 ± 0.40; E, 3.60 ± 0.75) were found to be more effective since control fish showed further advancement in maturation (GSI, 21.20 ± 1.10; E, 7.33 ± 0.74) during the peak breeding season (15th June). Histological observations also confirmed the results revealing a delayed initiation of ovarian development in the case of higher doses of letrozole and grape seed extracts. These results indicate the possible use of aromatase inhibitors in arresting the early maturation process in IMC.  相似文献   
39.
Seaweeds are important marine renewable resources. Use of seaweeds as fertilizers has allowed for substitution in place of conventional synthetic fertilizers. This study was conducted to examine the effect of seaweed liquid extract (SLE) on growth, yield, and nutrient uptake by hybrid maize. The experiments were conducted in ZARS, Vishweshwaraiah Canal farm, Mandya (Karnataka, India) during the rabi season of 2011–2013 to study the effect of foliar applications of Kappaphycus alvarezii (K sap) and Gracilaria edulis (G sap) sap on growth and yield response of hybrid maize “NAH 1137”. Three foliar sprays of both saps were applied at the rate of 2.5, 5.0, 7.5, 10, and 15.0% (v/v) along with water spray as a control at different stages of the crop. It was found that grain yield increased significantly by 18.54% and 26.04% for plants receiving 10% concentrations of both K. alvarezii and G. edulis sap respectively, over control. The increase in yield was attributed to increase in the number of rows in cob, cob length, and 100 grain weight. This investigation concludes that application of both the saps at 10% increased the nutrient uptake, grain, and stover yield over control.  相似文献   
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