Nonrandom processes maintain diversity in tropical forests     

Wills C  Harms KE  Condit R  King D  Thompson J  He F  Muller-Landau HC  Ashton P  Losos E  Comita L  Hubbell S  Lafrankie J  Bunyavejchewin S  Dattaraja HS  Davies S  Esufali S  Foster R  Gunatilleke N  Gunatilleke S  Hall P  Itoh A  John R  Kiratiprayoon S  de Lao SL  Massa M  Nath C  Noor MN  Kassim AR  Sukumar R  Suresh HS  Sun IF  Tan S  Yamakura T  Zimmerman J 《Science (New York, N.Y.)》2006,311(5760):527-531

An ecological community's species diversity tends to erode through time as a result of stochastic extinction, competitive exclusion, and unstable host-enemy dynamics. This erosion of diversity can be prevented over the short term if recruits are highly diverse as a result of preferential recruitment of rare species or, alternatively, if rare species survive preferentially, which increases diversity as the ages of the individuals increase. Here, we present census data from seven New and Old World tropical forest dynamics plots that all show the latter pattern. Within local areas, the trees that survived were as a group more diverse than those that were recruited or those that died. The larger (and therefore on average older) survivors were more diverse within local areas than the smaller survivors. When species were rare in a local area, they had a higher survival rate than when they were common, resulting in enrichment for rare species and increasing diversity with age and size class in these complex ecosystems.  相似文献   

Evaluation of the specificity of three enzyme-linked immunosorbent assays for detection of antibodies against Salmonella in bovine bulk milk     

Ann-Kristin J Nyman  Estelle CC ?gren  Karin Bergstr?m  Helene Wahlstr?m 《Acta veterinaria Scandinavica》2013,55(1):5

Background

The Swedish Salmonella control program has been running for decades and has resulted in a low prevalence of Salmonella in Swedish food producing animals. Routine bacteriology is used to detect Salmonella, however, bacteriology is time consuming, costly and has a low sensitivity. Different enzyme-linked immunosorbent assays (ELISAs) have been developed for detection of antibodies against Salmonella Dublin and S. Typhimurium in bovine bulk milk, individual milk samples as well as in sera. Screening bulk milk for antibodies against Salmonella spp. could improve the cost-effectiveness of the surveillance in Swedish dairy cattle, but as characteristics of tests may vary in different populations, tests should always be evaluated in the specific population where they will be used. Hence, the aim of this study was to evaluate the specificities of three bovine ELISAs when used to analyse bulk milk samples from Swedish dairy cattle. A second aim was to compare the performance of the two Dublin ELISAs tested.

Methods

Bulk milk samples for analysis were randomly selected from samples collected within the Swedish bulk milk sampling scheme and analyzed with the three ELISAs; a Danish in-house Dublin ELISA, PrioCHECK® Salmonella Ab bovine Dublin ELISA and PrioCHECK® Salmonella Ab bovine ELISA (hereafter named mixed ELISA). The specificities of the ELISAs were calculated assuming a disease-free status in Sweden i.e. that all test positive samples were assumed to be false positive results. This assumption can be used when a disease is known to be infrequent.

Results

The calculated specificities of the two Dublin ELISAs and the mixed ELISA, when using the producer’s recommended cut-off value of the corrected optic-density percent (ODC%) were 99.4% (95% Confidence Interval (CI): 98.8% -99.8%), 99.4% (95% CI: 98.8% -99.8%) and 97.9% (95% CI: 96.8% -98.7%), respectively. The correlation between the ODC% values of the two Dublin ELISAs was 0.83.

Conclusions

We conclude that the evaluated ELISAs have sufficiently high specificities to be used as supplement to bacteriological examinations in the Swedish Salmonella control program in cattle as well as a primary screening test in routine surveillance for S. Dublin.  相似文献   

Effects of butorphanol versus dexmedetomidine sedation on intradermal allergen and histamine responses in dogs with atopic dermatitis     

Milivoj A. Milosevic  Christine L. Cain  Linda A. Frank  Barton W. Rohrbach 《Veterinary dermatology》2013,24(6):582-e140

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Identification of cytotoxic constituents of Narthecium ossifragum using bioassay-guided fractionation     

Uhlig S  Wisløff H  Petersen D 《Journal of agricultural and food chemistry》2007,55(15):6018-6026

Narthecium ossifragum, a member of the Liliaceae family, contains phytochemicals that have hepatotoxic and nephrotoxic activity in several ruminant species. 3-Methoxyfuran-2(5H)-one has previously been isolated as the principal nephrotoxin, and its toxicity has been confirmed in vivo. However, previous investigations into the nephrotoxicity of N. ossifragum both in vivo and in vitro indicate that other phytochemical factors might contribute to the nephrotoxicity of the plant. In this study, the cytotoxicity in renal tubular cells (LLC-PK1) was measured using an aqueous extract from the plant and fractions from chromatographic separation to identify the cytotoxic constituents of the extract. In an iterative process two different groups of compounds were identified as the major cytotoxic principles in LLC-PK1 cells: steroidal saponins (primarily di- and trisaccharides of sarsasapogenin) and 5-hydroxy-4-methoxyfuran-2(5H)-one. Up to a concentration of 880 microg/mL (7.7 M) 3-methoxyfuran-2(5H)-one was not cytotoxic. The cytotoxicity of the saponins was abolished upon hydrolysis, indicating that the carbohydrate moiety of the molecule is a prerequisite for toxicity on the cellular level. The results of the present study have two important implications: first, the results question the direct involvement of 3-methoxyfuran-2(5H)-one in the nephrotoxicity of N. ossifragum; second, the findings should induce future investigations into the possible role of saponins in N. ossifragum-related nephrotoxicosis observed in ruminants that graze on this plant.  相似文献   

Urease from cotton (Gossypium hirsutum) seeds: isolation, physicochemical characterization, and antifungal properties of the protein     

Menegassi A  Wassermann GE  Olivera-Severo D  Becker-Ritt AB  Martinelli AH  Feder V  Carlini CR 《Journal of agricultural and food chemistry》2008,56(12):4399-4405

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In vivo aroma release of milk gels of different hardnesses: inter-individual differences and their consequences on aroma perception     

Gierczynski I  Laboure H  Guichard E 《Journal of agricultural and food chemistry》2008,56(5):1697-1703

The effect of textural modifications of solid milk gels on in vivo aroma release and aroma perception was investigated with a panel of 14 subjects. Great inter-individual differences were observed on aroma-release data, and the consequences of these differences on aroma perception were studied. From a hierarchical cluster analysis performed with several parameters extracted from release curves, the subjects were gathered into two groups, and a specific aroma-release profile was identified for each one. Then, by using a sensory profile, we showed that the intensity of the aroma perception was dependent on the release profile presented by the panelist. Second, we observed that, during the chewing phase, the aroma was perceived as more intense for the firmer gel and for panelists for whom the aroma release begins during the chewing of the product.  相似文献   

Dietary yeast affects preference and performance in <Emphasis Type="Italic">Drosophila suzukii</Emphasis>     

Nathalie Bellutti  Andreas Gallmetzer  Gerd Innerebner  Silvia Schmidt  Roland Zelger  Elisabeth Helene Koschier 《Journal of pest science》2018,91(2):651-660

Yeasts play an important role in nutrition physiology and host attraction of many Drosophila species, and associations with various yeast species are documented for several drosophilid flies. The pest Drosophila suzukii (Matsumura) has a predominant association with the yeast Hanseniaspora uvarum. However, research has not been conducted on the nutritional physiology of the yeasts associated with D. suzukii (spotted wing drosophila). Therefore, in this study, we determined whether dietary yeast was nutritionally relevant and whether yeast species closely associated with D. suzukii positively affected life-history traits. Our results confirm a crucial role of dietary yeast in the larval development and survival of D. suzukii. Furthermore, we found specific effects of the closely associated yeast species H. uvarum and Candida sp. on larval survival. Observations of the egg-laying behaviour of D. suzukii on cherry fruits artificially colonised with different yeast species revealed that the number of eggs laid increased on fruits colonised with Candida sp. and Saccharomyces cerevisiae.  相似文献   

Retrospective evaluation of 155 adult equids and 21 foals with tetanus from Western,Northern, and Central Europe (2000–2014). Part 2: Prognostic assessment          下载免费PDF全文

Gaby van Galen DVM  PhD  DECEIM  Joke Rijckaert DVM  Tim Mair BVSc  PhD  DECEIM  Helene Amory DVM  PhD  DECEIM  Lara Armengou DVM  PhD  DECEIM  Barbora Bezdekova DVM  PhD  DECEIM  Inge Durie DVM  DECEIM  Rikke Findshøj Delany DVM  Nathalie Fouché DVM  Laura Haley MVB  Michael Hewetson BVSc  DECEIM  Rene van den Hoven DVM  PhD  DECEIM  Anna Kendall DVM  DECEIM  Fernando Malalana DVM  DECEIM  MRCVS  Jessika Muller Cavalleri DVM  DECEIM  PhD  Tresemiek Picavet DVM  DECEIM  Katja Roscher DVM  DECEIM  Denis Verwilghen DVM  PhD  DECVS  Cornélie Westermann DVM  PhD  DECEIM  Claude Saegerman DVM  PhD  DECVPH 《Journal of Veterinary Emergency and Critical Care》2017,27(6):697-706

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Willingness to pay for compulsory deworming of pets entering Sweden to prevent introduction of Echinoccoccus multilocularis     

Höjgård S  Sundström K  Christensson D  Hallgren G  Hjertqvist M  Wallensten A  Vågsholm I  Wahlström H 《Preventive veterinary medicine》2012,106(1):9-23

To investigate if the Swedish entry rules for pets to prevent the introduction of Echinococcus multilocularis (EM) are proportional (i.e. that their costs do not exceed the value of their benefits), a dichotomous-choice contingent valuation study was conducted. The study was performed before the first case of EM was detected in Sweden in February 2011. About 5000, randomly selected, Swedish citizens were invited to participate and 2192 of them (44%) accepted to do so. Missing information on whether or not one would accept to pay for keeping the rules for 143 respondents resulted in 2049 observations (41%) available for the estimation of willingness to pay (WTP), and missing information on personal characteristics for another 274 respondents reduced the number of observations available for sensitivity analysis to 1775 (36%). Annual expected WTP for keeping the rules ranged between € 54.3 and € 99.0 depending on assumptions about compensations demanded by respondents not willing to pay. The estimates are conservative since only answers from respondents that were absolutely certain they would pay the suggested bid were regarded as yes-responses. That WTP is positive implies that Swedish citizens perceived the benefits of the rules to be larger than their costs.  相似文献   

Effect of nitrous oxide on the minimum alveolar concentration for sevoflurane and the minimum alveolar concentration derivatives that prevent motor movement and autonomic responses in dogs     

Seddighi R  Egger CM  Rohrbach BW  Hobbs M  Doherty TJ 《American journal of veterinary research》2012,73(3):341-345

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