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231.
The influence of thematic resolution on metric selection for biodiversity monitoring in agricultural landscapes 总被引:4,自引:3,他引:4
Debra Bailey Regula Billeter Stéphanie Aviron Oliver Schweiger Felix Herzog 《Landscape Ecology》2007,22(3):461-473
The objective of this paper is to investigate the relationship between landscape pattern metrics and agricultural biodiversity
at the Temperate European scale, exploring the role of thematic resolution and a suite of biological and functional groups.
Factor analyses to select landscape-level metrics were undertaken on 25 landscapes classified at four levels of thematic resolution.
The landscapes were located within seven countries. The different resolutions were considered appropriate to taxonomic and
functional group diversity. As class-level metrics are often better correlated to ecological response, the landscape-level
metric subsets gained through exploratory analysis were additionally used to guide the selection of class-level metric subsets.
Linear mixed models were then used to detect correlations between landscape- and class-level metrics and species richness
values. Taxonomic groups with differing requirements (plants, birds, different arthropod groups) and also functional arthropod
groups were examined. At the coarse scale of thematic resolution grain metrics (patch density, largest patch index) emerged
as rough indicators for the different biological groups whilst at the fine scale a diversity metric (e.g. Simpson’s diversity
index) was appropriate. The intermediate thematic resolution offered most promise for biodiversity monitoring. Metrics included
largest patch index, edge density, nearest neighbour, the proximity index, circle and Simpson’s diversity index. We suggest
two possible applications of these metrics in the context of biodiversity monitoring and the identification of biodiversity
hot spots in European agricultural landscapes. 相似文献
232.
J E Wheaton S N al-Raheem J A Godfredson J M Dorn E A Wong W Vale J Rivier T F Mowles E P Heimer A M Felix 《Journal of animal science》1988,66(11):2876-2885
Osmotic pumps were evaluated for 7-d delivery of growth hormone-releasing factor (GRF). In Exp. 1, 12 steers weighing 253 kg received hGRF(1-29)NH2 in H2O at rates of 0, 3, 30 and 300 pmol.h-1.kg-1. Pumps were implanted s.c. on d 0 and removed at 1200 on d 7. Blood samples were drawn at 20-min intervals from 0800 to 1200 on d -1, 1, 3, 5, 7 and 9. Growth hormone levels were not altered by GRF treatment (P greater than .05). Solubility and volume limitations render hGRF(1-29)NH2 delivery via osmotic pumps problematical. Flow rate and duration of release of dimethyl sulfoxide (DMSO):H2) (1:1) from osmotic pumps incubated in vivo and in vitro were found to be consistent with manufacturer's specifications. Two hGRF(1-29) analogues, Ro23-7863 and 4SG-29, were dissolved in DMSO:H2O. In Exp. 2, six 222-kg steers had pumps implanted and blood samples were taken as in Exp. 1. Three steers received each analogue at a rate of 300 pmol.h-1.kg-1. Analogues had similar GH-releasing ability and GH levels differed (P less than 0.001) among days, being approximately fourfold higher on d 3, 5 and 7 than on d -1, 1 and 9. Residual analogue solutions retained full bioactivity after 7-d implantation, and in vitro biopotencies of Ro23-7863 and 4SG-29 were similar (Exp. 3). In Exp. 4, 15 wethers (means = 31.3 kg) received osmotic pumps delivering 0, 3, 15, 75 and 300 pmol.h-1.kg-1 Ro23-7863 in DMSO:H2O for 7 d. Lambs were bled at 0800 and 1400 from d -1 to 8. The latter two doses increased (P less than .01) mean GH levels 2.7- and 4.3-fold over those in control animals during the treatment period. Results demonstrate that increased GH secretion can be elicited in steers and wethers for 1 wk by continuous s.c. infusion of GRF analogues utilizing osmotic pumps. 相似文献
233.
González-Jara P Atencio FA Martínez-García B Barajas D Tenllado F Díaz-Ruíz JR 《Phytopathology》2005,95(8):894-901
ABSTRACT The effects on symptom expression of single amino acid mutations in the central region of the Plum pox virus (PPV) helper component-proteinase (HC-Pro) gene were analyzed in Nicotiana benthamiana using Potato virus X (PVX) recombinant viruses. PVX recombinant virus expressing the wild-type variant of PPV HC-Pro induced the expected enhancement of PVX pathogenicity, manifested as necrosis and plant death. Recombinant virus expressing a variant of PPV HC-Pro containing a single point mutation ( HCL(134)H) was unable to induce this synergistic phenotype. The RNA silencing suppressor activity of PPV HC-Pro was demonstrated in a transient silencing suppression assay. In contrast, the HCL(134)H mutant showed no such activity. These results indicate that a unique point mutation in PPV HC-Pro impaired its ability to suppress RNA silencing and abolished its capacity to induce synergism, and clearly shows for the first time the link between these two functions in potyvirus HC-Pro. Additionally, we compared the effects on virus accumulation in N. benthamiana plants infected with either the PVX recombinant constructs or with native viruses in double infection experiments. PVX (+) and (-) strand genomic RNA accumulated at similar levels in plants infected with PVX recombinants, leading to an increase in PVX pathology, compared with plants infected with PVX alone. This finding confirms that the enhancement of pathogenicity associated with synergistic interaction is not a consequence of more efficient PVX replication due to RNA silencing suppression by PPV HC-Pro. 相似文献
234.
235.
Optimization of surfactin production from Bacillus subtilis in fermentation and its effects on Clostridium perfringens‐induced necrotic enteritis and growth performance in broilers
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Yeong‐Hsiang Cheng Ning Zhang Jin‐Cheng Han Ching‐Wen Chang Felix Shih‐Hsiang Hsiao Yu‐Hsiang Yu 《Journal of animal physiology and animal nutrition》2018,102(5):1232-1244
Bacillus species are commonly used as probiotics in the poultry feed industry for preventing infectious diseases and improving productivity by altering gastrointestinal microbiota. The growth parameters of Bacillus subtilis for surfactin production in fermentation and the benefits of surfactin on broiler chickens remain unclear. In this study, we examined the growth parameters of B. subtilis in fermentation and evaluated the effects of surfactin from B. subtilis‐fermented products on Clostridium perfringens‐induced necrotic enteritis and growth performance in broilers. Results showed that the highest viable biomass of B. subtilis was observed at 10% molasses and 2% yeast supplementation during fermentation. The 4‐ and 6‐day fermented B. subtilis products were heat‐, acid‐ and bile‐resistant. Furthermore, the 4‐day fermented B. subtilis products with the highest surfactin concentration showed the maximal antimicrobial activity against pathogens, including Escherichia coli, Staphylococcus aureus, Salmonella typhimurium and C. perfringens. Dietary B. subtilis‐fermented product supplementation in broilers significantly improved intestinal morphology and necrotic lesions under C. perfringens challenge. Bacillus subtilis treatments could enhance broiler productivity, as well as promote bone quality and intestinal morphology. These results together indicate that B. subtilis‐fermented products containing surfactin have potential for the development as feed additives and use as possible substitutes for antibiotics to treat C. perfringens in the poultry industry. 相似文献
236.
Context
Although uncertainties are ubiquitous in landscape planning, so far, no systematic understanding exists regarding how they should be assessed, appropriately communicated and what impacts they yield on decision support. With increasing interest in the role of uncertainties in science and policy, a synthesis of relevant knowledge is needed to further promote uncertainty assessment in landscape planning practice.Objectives
The aim of this paper is to synthesize knowledge about types of uncertainties in landscape planning, of methods to assess these uncertainties, and of approaches for appropriately coping with them.Methods
The paper is based on a qualitative literature review of relevant papers identified in the ISI Web of Knowledge and supplemented by frequently cited publications. The identification and synthesis of relevant information was guided by a developed framework concerning uncertainty in landscape planning.Results
The main types of uncertainties identified in landscape planning are data-, model-, projection- and evaluation uncertainty. Various methods to address these uncertainties have been identified, including statistical methods for the assessment of uncertainties in planning approaches that help to cope with uncertainties. The integration of uncertainty assessments into landscape planning results is lacking.Conclusions
The assessment of uncertainties in landscape planning have been addressed by science, but what is missing are considerations and ideas on how to use this knowledge to foster uncertainty analysis in landscape planning practice. More research is needed on how the application of identified approaches into landscape planning practice can be achieved and how these results might affect decision makers.237.
OBJECTIVE: To evaluate changes in pH of peritoneal fluid associated with CO2 insufflation during laparoscopy in dogs. ANIMALS: 13 client-owned dogs and 10 purpose-bred teaching dogs. PROCEDURES: Laparotomy was performed on control dogs; peritoneal fluid pH was measured at time of incision of the abdominal cavity (time 0) and 30 minutes later. Laparoscopic insufflation with CO2 was performed and routine laparoscopic procedures conducted on the teaching dogs. Insufflation pressure was limited to 12 mm Hg. Intraperitoneal fluid pH was measured by use of pH indicator paper at 4 time points. Arterial blood gas analysis was performed at the same time points. RESULTS: Peritoneal fluid pH did not change significantly between 0 and 30 minutes in the control dogs. For dogs with CO2 insufflation, measurements obtained were a mean of 8.5, 24.5, 44.5, and 72.0 minutes after insufflation. The pH of peritoneal fluid decreased significantly between the first (7.825 +/- 0.350) and second (7.672 +/- 0.366) time point. Blood pH decreased significantly between the first (7.343 +/- 0.078), third (7.235 +/- 0.042), and fourth (7.225 +/- 0.038) time points. The PaCO2 increased significantly between the first (39.9 +/- 9.8 mm Hg) and fourth (54.6 +/- 4.4 mm Hg) time points. Base excess decreased significantly between the first and all subsequent time points. CONCLUSIONS AND CLINICAL RELEVANCE: Pneumoperitoneum attributable to CO2 insufflation caused a mild and transient decrease in peritoneal fluid pH in dogs. Changes in peritoneal fluid associated with CO2 insufflation in dogs were similar to those in other animals. 相似文献
238.
Neuerer FF Horlacher K Truyen U Hartmann K 《Journal of Feline Medicine and Surgery》2008,10(3):247-251
In-house tests for the identification of faecal parvovirus antigen are now available. The majority of these are licensed for canine parvovirus only; but anecdotal information suggests that they will detect feline panleukopenia virus (FPV) as well. This prospective study was designed to compare five commercially available test systems. In total, 200 faecal samples from randomly selected healthy cats (148) and cats with diarrhoea (52) were tested and compared with the results of examination by electron microscopy. Ten cats were positive for FPV and all of these had diarrhoea. In-house canine parvovirus tests can be used to detect FPV. All tests were suitable to screen cats for faecal parvovirus excretion (positive predictive values for the Witness Parvo, the Snap Parvo, the SAS Parvo, the Fastest Parvo Strip, and the Speed Parvo were 100.0, 100.0, 57.1, 38.9, and 100%, respectively, negative predictive values for the Witness Parvo, the Snap Parvo, the SAS Parvo, the Fastest Parvo Strip, and the Speed Parvo were 97.4, 97.9, 98.9, 98.4, and 97.4%, respectively). In-house parvovirus tests may be positive up to 2 weeks after vaccination, and therefore, in recently vaccinated cats positive results do not necessarily mean infection. 相似文献
239.
Felix Kienast 《Landscape Ecology》1991,5(4):225-238
Possible effects of changing climate and increasing CO2 on forest stand development were simulated using a forest succession model of the JABOWA/FORET type. The model was previously tested for its ability to generate plausible community patterns for Alpine forest sites ranging from 220 m to 2000 m a.s.l., and from xeric to mesic soil moisture conditions. Each model run covers a period of 1000 yrs and is based on the averaged successional characteristics of 50 forest plots with an individual size of 1/12 ha. These small forest patches serve as basic units to model establishment, growth, and death of individual trees. The simulated CO2 scenario assumes linear climate change as atmospheric CO2 concentration increases from 310 l/l to 620 l/l and finally to 1340 l/l. Direct effects of increasing CO2 on tree growth were modeled using tree-ring and growth chamber data. The simulation experiment proved to be a useful tool for evaluating possible vegetation changes that might occur under CO2-induced warming. On xeric sites from the colline to the high montane belt, the simulated climate change causes drastic soil water losses due to elevated evapotranspiration rates. This translates into a significant biomass decrease and even to a loss of forest on xeric low-elevation sites. Biomass gains can be reported from mesic to intermediate sites between 600 and 2000 m a.s.l. Increasing CO2 and warming alters the species composition of the simulated communities considerably. In today's montane and subalpine belt an invasion of deciduous tree species can be expected. They outcompete most conifers which in turn may migrate to today's alpine belt. Some of these changes occur as early as 40 yrs after climate begins to change. This corresponds to a mean annual warming of 1.5°C compared with today's mean temperatures. 相似文献
240.
We investigated direct anthelmintic effects associated with the feeding of fresh tanniferous forages against established populations of Haemonchus contortus and Cooperia curticei in lambs. Twenty-four parasite naive lambs were inoculated with a single dose of infective larvae of these two parasites 27 days prior to the start of the feeding experiment. Lambs were individually fed with either chicory (Cichorium intybus), birdsfoot trefoil (Lotus corniculatus), sainfoin (Onobrychis viciifolia) or a ryegrass/lucerne mixture (control) for 17 days. Animals where then united to one flock and subjected to control feeding for another 11 days to test the sustainability of potentially lowered egg excretion generated by tanniferous forage feeding. When compared to the control, administration of all tanniferous forages was associated with significant reductions of total daily faecal egg output specific to H. contortus (chicory: 89%; birdsfoot trefoil: 63%; sainfoin: 63%; all tests P<0.05) and a tendency of reduced H. contortus worm burden (chicory: 15%; birdsfoot trefoil: 49% and sainfoin: 35% reduction). Irrespective of the condensed tannin (CT) containing fodder, no anthelmintic effects were found against C. curticei. Cessation of CT-feeding followed by non-CT control feeding did not result in a re-emergence of faecal egg counts based on faecal dry matter (FECDM) in any group, suggesting that egg output reductions are sustainable. The moderate to high concentrations of CTs in birdsfoot trefoil (15.2 g CTs kg(-1) dry matter (DM)) and sainfoin (26.1 g CTs kg(-1) DM) were compatible with the hypothesis that the antiparasitic effect of these forages is caused by their content of CTs. For chicory (3 g CTs kg(-1) DM), however, other secondary metabolites need to be considered. Overall, birdsfoot trefoil and in particular sainfoin seem promising candidates in contributing to an integrated control strategy against H. contortus not only by mitigating parasite related health disturbances of the host but also by a sustained reduction of pasture contamination. 相似文献