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101.
Controlled‐environment and field experiments were done to investigate effects of the fungicide Punch C (flusilazole plus carbendazim) on growth of Leptosphaeria maculans and L. biglobosa in oilseed rape. In controlled‐environment experiments, for plants inoculated with L. maculans, fungicide treatment decreased lesion size and amount of L. maculans DNA in leaves; for plants inoculated with L. biglobosa, fungicide did not affect lesion size or amount of pathogen DNA. When release of ascospores was monitored using a Burkard spore sampler, the timing and pattern of ascospore release differed between the four seasons. In 2006/2007, the majority of ascospores released were L. maculans, whilst in 2007/2008 the majority were L. biglobosa; in both seasons L. maculans ascospores were released before L. biglobosa ascospores. In field experiments in 2002/2003 and 2003/2004, fungicide treatment decreased severity of stem canker on cv. Apex, but gave no significant yield response. In 2006/2007 and 2007/2008, fungicide treatment decreased phoma leaf spot incidence in autumn and stem canker severity at harvest, and increased yield. Fungicide treatment decreased stem canker severity more on cv. Courage, with a good yield response, than on cv. Canberra. In 2002/2003 and 2003/2004, fungicide treatment decreased the frequency of spread of L. maculans into stem pith tissues and in 2006/2007 fungicide decreased the amount of L. maculans DNA in stem tissues (measured by quantitative PCR). These results are used to suggest how effects of fungicides on interactions between L. maculans and L. biglobosa might affect severity of phoma stem canker and yield response.  相似文献   
102.
Madagascar is currently developing a policy and strategies to enhance the sustainable management of its natural resources, encouraged by United Nations Framework Convention on Climate Change (UNFCCC) and REDD. To set up a sustainable financing scheme methodologies have to be provided that estimate, prevent and mitigate leakage, develop national and regional baselines, and estimate carbon benefits. With this research study this challenge was tried to be addressed by analysing a lowland rainforest in the Analanjirofo region in the district of Soanierana Ivongo, North East of Madagascar. For two distinguished forest degradation stages: “low degraded forest” and “degraded forest” aboveground biomass and carbon stock was assessed. The corresponding rates of carbon within those two classes were calculated and linked to a multi-temporal set of SPOT satellite data acquired in 1991, 2004 and 2009. Deforestation and particularly degradation and the related carbon stock developments were analysed. With the assessed data for the 3 years 1991, 2004 and 2009 it was possible to model a baseline and to develop a forest prediction for 2020 for Analanjirofo region in the district of Soanierana Ivongo. These results, developed applying robust methods, may provide important spatial information regarding the priorities in planning and implementation of future REDD+ activities in the area.  相似文献   
103.
Cilia: activation coupled to mechanical stimulation by calcium influx   总被引:2,自引:0,他引:2  
Ciliated epithelial cells in the oviduct of Necturus maculosus were stimulated mechanically by brief dimpling with a microstylus. This treatment produlced a transient depolarization of the membrane, and a transient increase in the frequency of ciliary beating. The increase in frequency of ciliary beating was related to the concentration of extracellular calcium ion, decreasing with reductiotn in calcium. Addition of lanthanum was followed by a decrease in spontaneous ciliary aictivity and a hyperpolarization of the membrane. In the presence of lanthanum, the transietnt depolarization in response to mechanical stimulation had a shorter timte course, and the concomitant increase in ciliary frequency was greatly reduced. It is concluded that calciuml ions enter the cell as a result of mechanical stimulationi of the membrane, and that calcium influx leads to an increase in the frequency of ciliary activity.  相似文献   
104.
Subcellular sources of luminescence in Noctiluca   总被引:2,自引:0,他引:2  
The perivacuolar cytoplasm of Noctiluca miliaris contains approximately 10(4) microsources of luminescence, with dimensions of 0.5 to 1.5 microns, which exhibit marked fluorescence with ultraviolet excitation. Local invasion by an action potential elicits light emission (microflashes) from these sources with a coupling latency of about 2 milliseconds. Magnitudes of the microflash vary directly with the dimensions of the source. Time courses of the microflash resemble that of the macroflash emitted by the whole cell but have somewhat shorter time constants. The small discrepancy induration between micro- and macroflash can be explained by the 5- to 10-millisecond asynchrony of microsource triggering that results from the conduction time of the action potential. Reversible gradations in amplitude of the macroflash, as from potentiation or fatigue, result from parallel summation of graded changes in microflash intensity. Thus the macroflash gives a reasonably true picture of the subcellular kinetics of luminescence.  相似文献   
105.
Hydrogen storage in microporous metal-organic frameworks   总被引:2,自引:0,他引:2  
Metal-organic framework-5 (MOF-5) of composition Zn4O(BDC)3 (BDC = 1,4-benzenedicarboxylate) with a cubic three-dimensional extended porous structure adsorbed hydrogen up to 4.5 weight percent (17.2 hydrogen molecules per formula unit) at 78 kelvin and 1.0 weight percent at room temperature and pressure of 20 bar. Inelastic neutron scattering spectroscopy of the rotational transitions of the adsorbed hydrogen molecules indicates the presence of two well-defined binding sites (termed I and II), which we associate with hydrogen binding to zinc and the BDC linker, respectively. Preliminary studies on topologically similar isoreticular metal-organic framework-6 and -8 (IRMOF-6 and -8) having cyclobutylbenzene and naphthalene linkers, respectively, gave approximately double and quadruple (2.0 weight percent) the uptake found for MOF-5 at room temperature and 10 bar.  相似文献   
106.
Residual calcium ions depress activation of calcium-dependent current   总被引:4,自引:0,他引:4  
Calcium ions enter and accumulate during depolarization of some cells, activating a potassium current, IK(Ca), that depends on the cytoplasmic concentration of calcium ions, [Ca]i. However, elevation of [Ca]i can depress IK(Ca) elicited by a subsequent membrane depolarization. The depression of IK(Ca) is ascribed here to a [Ca]i-mediated inactivation of the voltage-gated calcium conductance, which causes a net reduction in calcium ions available for the activation of IK(Ca). This suggests that other processes dependent on gated calcium entry may also be depressed by small background elevations in cytosolic free calcium ions.  相似文献   
107.
A review revealed that at 20 veterinary faculties in European countries parasitology is represented in the curriculum of veterinary medicine with an average of 105 core contact hours, devoted to lectures (58%) and practicals (42%). However, there is a high diversity between faculties with ranges of total contact hours between 48 and 156. Three faculties are close to the minimum of 70 core contact hours recommended by WAAVP (2002), and one faculty is below this limit. In one of the faculties parasitology is completely integrated into interdisciplinary teaching activities, in some others there are developments in this direction which include the risk of dissolving parasitology as a discipline. One faculty with a high degree of integrated teaching has already abolished the parasitological examination. Parasitology is preferentially taught in the years three, four and five of the curriculum, but there is great variation between the faculties. Most teachers in the faculties are veterinarians. In many faculties the large numbers of students and the unsatisfactory academic teaching staff:student ratio represent a significant problem. This problem may increase with more teaching obligations caused by new curricula. Due to the high diversity in content and structure of teaching curricula of veterinary medicine between veterinary faculties in Europe international and even national exchange of students is inhibited. Therefore, and for many other reasons more activities should be initiated towards harmonisation of the study curricula in Europe.  相似文献   
108.
Acepromazine, a phenothiazine tranquilizer, causes hypotension in standing horses ( Parry et al. 1982 ). However, a retrospective study ( Taylor & Young 1993 ) showed that acepromazine pre‐anesthetic medication did not affect arterial blood pressure (MAP) in anaesthetized horses. This study examined the effects of acepromazine on MAP during romifidine–ketamine–halothane anaesthesia in horses anaesthetized for various surgical procedures. Forty‐four horses were allocated by block randomization to groups A and B. Group A received acepromazine 0.05 mg kg?1 IM 30 minutes before induction of anaesthesia, group B did not. All horses received romifidine 0.1 mg kg?1 IV 5 minutes before anaesthesia was induced with diazepam 0.05 mg kg?1 and 2.2 mg kg?1 ketamine IV. The horses' trachea were intubated and horses breathed 50% oxygen and 50% nitrous oxide plus halothane (concentration adjusted as required clinically) from a circle breathing system. Nitrous oxide was discontinued after 10 minutes and analgesics, flunixin 1.1 mg kg?1 and either morphine 0.1 mg kg?1 or butorphanol 0.05 mg kg?1 (matched for horses undergoing the same procedure) administered IV. The facial or dorsal metatarsal artery was catheterized for direct measurement of MAP (every 10 min) and withdrawal of blood for gas analysis (every 30 min). The electrocardiogram (ECG) was monitored continuously with a 10 seconds printout obtained every 10 minutes. Intermittent positive pressure ventilation (IPPV) was instigated if PaCO2 exceeded 9.3 kPa (70 mm Hg). Dobutamine was infused (1.0–5.0 kg?1minute?1) if MAP < 58 mm Hg and was continued until MAP > 70 mm Hg. Mean age, weight and duration of anaesthesia were compared between the groups using a t‐test for independent samples. Gender distribution and numbers of horses requiring IPPV or dobutamine were compared between groups using a chi‐squared test (with Yates correction). To compare MAP over time, the area under the curve (MAPAUC) was calculated and compared between groups using a t‐test. Horses receiving dobutamine were excluded from MAPAUC and MAP comparisons. The ECG printouts were examined for arrhythmias. There were no significant differences between groups (p > 0.05). Group A contained three stallions, 10 geldings and nine mares, aged 6.3 years (range 0.75–18). Group B comprised eight stallions, 11 geldings and three mares aged 7.3(1–16) years. Duration of anaesthesia was group A 97 (50–140) minutes, group B 99 (50–160) minutes. Eight horses in group A and three in group B required IPPV. Nine horses in group A and four in group B received dobutamine. Mean arterial pressure ranged from 60 to 128 mm Hg in group A and 58–96 mm Hg in group B. Mean MAPAUC was 5941 mm Hg minute?1 in group A, in B 6000 mm Hg minute?1. Atrial pre‐mature complexes were recorded from one horse in group B. No other arrhythmias were detected. Although MAP was lower in the acepromazine group, this appeared unlikely to cause a clinical problem. The incidence of arrhythmias was too low to determine the influence of acepromazine in this study.  相似文献   
109.
Im Rahmen einer Umweltverträglichkeitsbewertung werden quantifizierbare und kontrollfähige Kriterien des Pflanzenschutzmitteleinsatzes festgelegt und kritische Belastungen erarbeitet. Damit sollen sowohl Betriebsvergleiche ermöglicht als auch der Landwirtschaft ein Rahmen vorgegeben werden, der den tolerierbaren Bereich des Mitteleinsatzes absteckt. Mit Blick auf öffentliche Akzeptanzproblerne des Pflanzenschutzmitteleinsatzes sind neben potentiellen Umweltbeeinträchtigungen auch öffentliche Ängste in Bewertungsprozesse einzubeziehen. Die Kriterien Wirkstoffmenge, untersetzt nach Anwendungsgruppen, Mitteltoxizität und Ausbringungstechnologie könnten diesen Forderungen gerecht werden, da sie auf Minimierung der Wirkstoffmenge, Optimierung der Ausbringung und Auswahl mindertoxischer Mittel orientieren. Die kritische Belastung bildet somit nicht die Grenze zum umweltschädigenden, sondern zum unnötigen Bereich.  相似文献   
110.
OBJECTIVE: To determine economic losses associated with an outbreak of avian influenza in flocks in Pennsylvania during 1997 and 1998. SAMPLE POPULATION: 5 premises containing avian influenza-infected layer, pullet, and turkey flocks. PROCEDURE: Losses incurred before depopulation, those incurred at the time of depopulation, and those that were attributable to depopulation (unrealized loss of income) were evaluated. Results were extrapolated to provide values for all infected flocks. RESULTS: Extrapolating the costs determined on the basis of age and number of birds from the 5 sample flocks to all other flocks infected with nonpathogenic avian influenza H7N2 yielded an estimated total cost to the Pennsylvania poultry industry of $3.5 million. CLINICAL IMPLICATIONS: The H7N2 virus is not highly pathogenic. If the pathogenicity of the virus does not change, then the poultry industry and state and federal governments will not have severe economic losses for the 1997-1998 outbreak similar to those for the 1983-1984 avian influenza outbreak in Pennsylvania. To decrease the potential for financial losses that could result from future outbreaks of avian influenza, it is essential that the commercial industry and livebird market system be separated via increased use of biosecurity measures.  相似文献   
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