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11.
Magnus Lf Gunnar Isacsson Dan Rydberg Torkel N. Welander 《Forest Ecology and Management》2004,190(2-3):281-290
The influence of above-ground insect herbivory and other agents of damage to seedlings was studied in a field experiment. Nine different tree species were planted in each of five randomised blocks. The species were: Alnus glutinosa (L.) Gaertner, Betula pendula Roth., Fagus sylvatica L., Fraxinus excelsior L., Larix eurolepis Henry, Picea abies (L.) Karst., Prunus avium L., Quercus robur L. and Tilia cordata Mill. The seedlings were monitored through the 2000–2002 growing seasons. Pine weevils (Hylobius abietis L.) fed significantly more on Norway spruce seedlings than on all other tree species. The following rough preference order was obtained: Norway sprucelarch>birch, beech, oak>cherry>alder, ash, lime. Thus, during the conversion of single-species coniferous plantations to mixed-species broadleaved stands, the use of costly insecticides against pine weevil is not required. Short-snouted weevils (e.g. Strophosoma melanogrammum Forst. and Otiorhynchus scaber L.) and other insects caused leaf and needle area loss primarily during the first growing season. 相似文献
12.
A preliminary trial of the sedation induced by intranasal administration of midazolam alone or in combination with dexmedetomidine and reversal by atipamezole for a short‐term immobilization in pigeons
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Slavomir Hornak Tomas Liptak Valent Ledecky Rudolf Hromada Jan Bilek David Mazensky Vladimir Petrovic 《Veterinary anaesthesia and analgesia》2015,42(2):192-196
ObjectiveTo assess the sedative and immobilization effect of intranasal administration (INS) of midazolam (MID) without or with INS dexmedetomidine (DXM), and some physiological changes induced by the drugs. The ability of INS atipamezole to reverse the DXM component was also assessed.Study designProspective ‘blinded’ experimental study.AnimalsIn total, 15 pigeons.MethodsPigeons were sedated by INS MID alone at a dose of 5 mg kg−1 (group MID, n = 6) or in combination with INS DXM at a dose 80 μg kg−1 (group MID-DXM, n = 6). Measurements were made of heart rate (HR), respiratory rate (fR) and cloacal temperature (CT). The degree of sedation was assessed at 15 minutes prior to, immediately after, and at intervals until 100 minutes after drug administrations. Following MID-DXM, INS atipamezole (250 μg kg−1) was administered and the same indices measured 5 and 10 minutes later.ResultsMID had no effect on HR and fR, and although CT decreased, it remained within physiological range. MID-DXM caused significant falls in HR, fR and CT that persisted until the end of sedation. Atipamezole antagonized sedation and cardiorespiratory side effects of MID-DXM within 10 minutes of application. In addition, for MID compared to MID-DXM, the lowest sedation scores [10 (7–14) and 10.5 (5–14) versus 2 (1–4) and 2 (1–5)] were achieved in the 10th and 20th minute versus the 20th and 30th minute of the sedation, respectively.Conclusions and clinical relevanceMID alone, given INS had minimal side effects on vital functions but caused inadequate immobilization of pigeons for restraint in dorsal recumbency. MID-DXM caused an effective degree of immobilization from 20 to 30 minutes after administration, at which time birds tolerated postural changes without resistance. Atipamezole antagonized both side effects and sedation, but complete recovery had not occurred within 10 minutes after its application. 相似文献
13.
Carlos E Hernandez Tomas Thierfelder Kerstin Svennersten-Sjaunja Charlotte Berg Agustin Orihuela Lena Lidfors 《Acta veterinaria Scandinavica》2014,56(1)
Background
Measurement of salivary cortisol has been used extensively as a non-invasive alternative to blood sampling to assess adrenal activity in ruminants. However, there is evidence suggesting a considerable delay in the transfer of cortisol from plasma into saliva. Previous studies in cattle have used long sampling intervals making it difficult to characterise the relationship between plasma and salivary cortisol (PLCort and SACort, respectively) concentrations at different time points and determine whether or not such a time lag exist in large ruminants. Therefore, the objective of this study was to characterise the relationship between plasma and salivary cortisol and determine if there is a significant time lag between reaching peak cortisol concentrations in plasma and saliva across a 4.25 h time-period, using short sampling intervals of 10–15 min, following social separation in dairy cattle.Five cows were separated from their calves at 4 days after calving, and six calves were separated from a group of four peers at 8 weeks of age. Following separation, the animals were moved to an unfamiliar surrounding where they could not see their calves or pen mates. The animals were catheterised with indwelling jugular catheters 1 day before sampling. Blood and saliva samples were obtained simultaneously before and after separation.Results
In response to the stressors, PLCort and SACort increased reaching peak concentrations 10 and 20 min after separation, respectively. This suggested a 10 min time lag between peak cortisol concentrations in plasma and saliva, which was further confirmed with a time-series analysis. Considering the 10 min time lag, SACort was strongly correlated with PLCort (P < 0.0001).Conclusions
Salivary cortisol correlates well with plasma cortisol and is a good indicator of the time-dependent variations in cortisol concentrations in plasma following acute stress. However, there is a time lag to reach peak cortisol concentrations in saliva compared to those in plasma, which should be considered when saliva samples are used as the only measure of hypothalamic-pituitary-adrenal axis response to stress in cattle. 相似文献14.
15.
Six Swedish and one Canadian single spore isolate of Drechslera teres f. teres were used to screen 109 barley lines for disease
resistance and to select a differential set of barley lines for use in assessing pathogen virulence. A large variation for
net blotch resistance was found among the 109 barley lines which were classified into four groups, those showing: 1) only
resistant reactions; 2) differential reactions; 3) only intermediate reactions and 4) only susceptible reactions. The European
commercial varieties included, showed susceptibility to all Swedish isolates, but a few were resistant to the Canadian isolate.
The 18- member differential set separated 25 Swedish and two Canadian isolates of D. teres into 14 pathotypes, three of which
made up 59% of the isolates. Only one barley differential (CI 9776) was resistant to all net form isolates. Host selection
on the pathogen seems to be present as all six isolates obtained from cv. Golf belonged to the same pathotype and 4 of 5 isolates
from cv. Karin shared the same virulence pattern. The net form of net blotch (D. teres f. teres) predominated in the sampled
regions and only one of 26 Swedish isolates was of the spot form (D. teres f. maculata).
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
16.
Tetrahydro-beta-carbolines are biologically active alkaloids that occur and accumulate in mammalian tissues, fluids, and brain, but their ultimate origin or biological role is still uncertain. Four tetrahydro-beta-carboline alkaloids: 1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid, 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid, 1-methyl-1,2,3,4-tetrahydro-beta-carboline, and 6-hydroxy-1-methyl-1,2,3,4-tetrahydro-beta-carboline, are found as naturally occurring substances in some fruit and fruit juices. These compounds occur in the microg/g level in those products, and a characteristic and distinct profile appears to exist depending on the type of fruit and juice involved. Thus, 1-methyl-1,2,3,4-tetrahydro-beta-carboline may appear in tomato, tomato juice, and kiwi; 6-hydroxy-1-methyl-1,2,3,4-tetrahydro-beta-carboline in bananas, pineapple, tomato, and their corresponding juices; and 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid in oranges and grapefruits, although it also occurred in most juices. Fruit-occurring tetrahydro-beta-carboline alkaloids acted as antioxidants and free radical scavengers in the ABTS assay when compared with ascorbic acid and Trolox. This suggests that tetrahydro-beta-carboline alkaloids might act as antioxidants when absorbed and accumulated in the body, contributing to the antioxidant effect of fruit products containing these compounds. 相似文献
17.
Denaturation of proteins from striated and smooth muscles of scallop (Zygochlamys patagonica) was studied with differential scanning calorimetry (DSC) by monitoring maximum temperatures of transition and denaturation enthalpies. DSC thermograms of both striated and smooth whole muscles showed two transitions: Tmax 55.0, 79.2 degrees C; and Tmax 54.7, 78.7 degrees C, respectively. The DSC thermograms of myofibrils and actomyosin were similar to those corresponding to their respective whole muscles. As pH and ionic strength increased, the thermal stability of whole muscles decreased. The pH increase (5.0-8.0) significantly (p < 0.01) decreased the denaturation enthalpies (deltaH total, deltaH peakI, and deltaH peakII) of whole striated muscles. A significant decrease (p < 0.05) in the deltaH total and the deltaH peakI was also observed in DSC thermograms of smooth muscles at pH 8.0. Denaturation enthalpies (deltaH total and deltaH peakI) significantly decreased (p < 0.01) when the ionic strength increased from 0.05 to 0.5 in both types of muscles. Striated muscles were more affected than smooth muscles by changes in the chemical environment. 相似文献
18.
Inter Simple Sequence Repeat (ISSR) Analysis of Diploid Coffee Species and Cultivated Coffea arabica L. from Tanzania 总被引:1,自引:0,他引:1
Inter simple sequence repeat (ISSR) markers were used to evaluate levels of genetic similarity among Coffea arabica L. accessions from Tanzania and to estimate levels of genetic similarities in C. arabica and diploid coffee species. The six ISSR primers used generated a total of 82 fragments and the dissimilarity values ranged
from 0.21 to 1. Mean dissimilarity values between provenances (0.56–0.85) were higher than within provenances (0.37–0.68).
Cluster analysis based on Nei’s genetic distances showed C. arabica provenances grouping based on geographical origin. Two major clusters were formed that constituted of provenances from Kilimanjaro
and Arusha in one sub-cluster; Tanga and Morogoro in the other; the second cluster had Mbeya provenances and diploid species,
respectively. The implication is that Mbeya provenances are different from the rest of Tanzanian C. arabica. A principal coordinate analysis (PCA), whose first three coordinates explained 43% of the variation, showed similar groupings
as in the cluster analysis. A separate cluster analysis of diploid species showed a distinct separation of the three species
used. ISSR data gave results similar to previous findings from random amplified polymorphic DNA(RAPD) analysis. The results
also confirm the limited diversity present in cultivated C. arabica in Tanzania 相似文献
19.
Background, Aims and Scope Contaminated land is a high priority environmental problem in most of Europe and North-America. Sweden is no exception and
generic guideline values have been developed for the initial assessment, but site-specific assessments are also needed. The
generic guideline values are not applicable when the exposure conditions are different from the typical Swedish conditions
or when the site contains a particularly sensitive ecosystem. The Swedish guideline values have, like in many other countries,
been set by using deterministic point estimates for all variables and constants in the used multimedia model. The same approach
is common also for site-specific assessments, and a limitation is that it fails to quantify variability and uncertainty. Probabilistic
risk assessment provided a method to deal with this problem. Variability and uncertainty in the input parameters (variables
or constants) are described by probability distributions, and likewise the output (risk or exposure) is presented as a probability
distribution. A substantial number of probabilistic risk assessments for contaminated land at sites in North America, Europe
and Asia have been published. However, an extensive review of the literature did not identify any study where probabilistic
risk assessment was applied to a site contaminated by an iron or steel industry. Here we will describe such a case, where
we have compared a deterministic point estimate with a probabilistic risk assessment for six elements and benzo[a]pyrene.
Methods The site had different metallurgical plants in operation for more than 100 years. Most parts of the steel mill were closed
by the mid 1980s, and today the site is used by small-sized enterprises. The soil is contaminated with metals from the previous
industrial operations. The present owner plans to develop the site and has therefore initiated extensive investigations of
soil contamination. Sixty-two soil samples collected between 1997 and 2000 provided a good coverage of the whole site, and
were analyzed for the content of different elements and polycyclic aromatic hydrocarbons (PAH). The exposure assessments were
focused on six elements with high concentrations compared to the generic guideline values; arsenic (As), lead (Pb), cadmium
(Cd), chromium (Cr), copper (Cu) and zinc (Zn). In addition, benzo[a]pyrene was included due to the high toxicity and comparatively
high concentrations. Variability and uncertainty were characterized in a Monte Carlo simulation of exposures (10 000 iterations),
and the exposures were evaluated with two land use scenarios; less sensitive use and sensitive use.
Results and Discussion The deterministic point estimates and the probabilistic estimates of the 95th percentile are in approximately the same ranges
in the scenario of less sensitive land use. It is only the exposure for arsenic that is slightly above the toxicological reference
value (TRV) in the deterministic assessment. In the probabilistic assessment, the exposure for all elements is below the TRV.
The results for sensitive land use are applicable to a scenario where the site is developed for general housing. The deterministic
point estimates and the probabilistic estimates of the 95th percentile are also here in approximately the same ranges, but
the exposure exceeds the TRV for arsenic, cadmium and lead. Drinking water, vegetables grown on site and soil ingestion are
the major exposure pathways for this scenario. In this assessment, the estimated intake distributions are applicable to a
randomly selected individual. The probability distributions used here to characterize the different soil parameters are typically
representing both variability and uncertainty, and the same is true the majority of the exposure variables. We therefore decided
not to attempt to separate variability and uncertainty at this stage, but with additional data from a more in-depth site investigation
it might be possible to achieve this.
Conclusions and Outlook To the best of our knowledge, this study is the first report on a probabilistic risk assessment on a former iron and steel
works site. The materials handled by this industry were less toxic than for many other metallurgical operations, but contaminants
may still severely limit the options for future land use. This case study shows that probabilistic exposure estimates for
a set of soil contaminants can be quite similar to deterministic point estimates. The main difference is instead to be found
in the additional information obtained with the probabilistic assessment. The sensitivity analyses show pathways and input
variables that contribute most to variations in the total intake of each contaminant, e.g. dermal contact and ingestion of
soil, vegetables and drinking water. This information can be used both in the planning of future land use and for active measures
to reduce current exposure. The probabilistic assessment also provides information on the magnitude of exposure and the margin
of safety. This information may facilitate risk communication between decision-makers and stakeholders. The presentation of
results from probabilistic risk assessments is only briefly discussed in the literature and here we see a need for research
and opportunities for enhancement. The choice of data analytical tools may then be of importance, since more complex multimedia
models are rather difficult to decipher when implemented within traditional spreadsheet software. Some of the research needs
are identified here and in a previous review article in this journal. 相似文献
20.
Undabeytia T Sanchez-Verdejo T Morillo E Maqueda C 《Journal of agricultural and food chemistry》2004,52(14):4493-4500
The influence of two organic amendments consisting of an urban waste compost (SUW) and a commercial amendment from olive mill wastes (OW) was assessed on the sorption properties and leaching of the ionizable herbicide imazaquin on four soils with different physicochemical characteristics. A loamy sand soil (CR), a loam soil (P44), a silt loam soil (AL), and a clay soil (TM), with low-medium organic matter contents, were chosen. Sorption-desorption experiments were performed on the original soils and on a mixture of these soils with the organic amendments at a rate of 6.25% (w/w). These mixtures were used just after preparation and after aging for 3 months. Imazaquin adsorption was higher on AL soil because of its high content of amorphous iron oxides, whereas it was related to the soils' organic matter (OM) contents on TM and CR soils and to acid pH on P44 soil. Addition of exogenous OM to soils caused a decrease in the adsorption of the herbicide with the only exception of CR soil, due to blocking of adsorptive surfaces and/or equilibrium pH rise. The extent of this decrease was dependent only on the nature of the added amendment on AL soil. The adsorbed amounts of imazaquin on aged organic fertilized soils were usually fairly close to that on original soils. Results of soil column experiments indicate that addition of exogenous organic matter cannot be considered as a regular practice for retarded movement of imazaquin. 相似文献