Vegetation structure influences the vertical stratification of open- and edge-space aerial-foraging bats in harvested forests     

Maria D. Adams  Bradley S. Law  Kris O. French 《Forest Ecology and Management》2009

Heavy logging leads to regrowth of dense forest, which may adversely affect the flight and foraging activities of bats. We compared insectivorous bat activity and insect abundance at three heights (understorey, subcanopy and canopy), two locations (forest and track) and three time periods (evening, night and dawn), in old and young regrowth sites in south-eastern Australia (456 detector-hours). We measured activity levels of all bats and four echolocation guilds—one open-space and three edge-space aerial-foraging guilds. Mean bat activity in the subcanopy and canopy was up to 11 times that in the understorey of forests, a pattern opposite to that of insect abundance. However, bat activity in the two upper strata was lower in young regrowth than in old regrowth. Vegetation was more cluttered in young regrowth at these upper heights (closer stems and less vertical space in the subcanopy). Mean activity on the track was 2–5 times higher than in the forest, particularly at understorey level (17 times higher for all bats), where vegetation was less cluttered (more distant understorey trees and shrubs, and less cover of ground vegetation). Time of night had little effect on bat activity. The negative response of bat guilds to increased clutter was strongest in the open-space guild and weakest in the edge-space guild with the highest frequency calls. There was an interaction between insect abundance and an index of vegetation openness, with high values of both variables producing high bat activity levels for all bats and the two highest frequency call guilds. Our results highlight the need for management practices in logged forests that increase or preserve the amount of flight and foraging space available to bats.  相似文献   

The Comet assay for detection of DNA damage in canine sperm          下载免费PDF全文

AF Pereira  P Borges  A Fontbonne  L Cardoso  I Gaivão  A Martins‐Bessa 《Reproduction in domestic animals》2017,52(6):1149-1152

Sperm DNA integrity is a fundamental prerequisite in fertilization and embryo development. Among DNA integrity tests, the Comet assay is an accurate and sensitive test for the detection of sperm oxidative damage. The aim of this work was to evaluate sperm oxidative damage using the Comet assay and to study the correlation between Comet and routine assays for the evaluation of semen quality. Dogs were divided in two groups: group A (n = 6), comprising dogs with abnormal spermiogram, that is astheno‐, terato‐ or oligoasthenoteratozoospermic (OAT); and group B (n = 8), comprising normospermic dogs. The distribution of sperm oxidative damage was significantly different between the two groups (p = .001): group A—median: 31.55%, interquartile range (IQR): 30.18–38.01; group B—median: 0.90%, IQR: 0.65–1.96. The correlation between oxidative damage and abnormal morphology was high (r = .846; p < .001). There was a negative correlation between progressive motility and oxidative damage (r = ?.792; p = .001). Basal and oxidative DNA damage of spermatozoa are increased in dogs with non‐normospermic semen. In conclusion, and considering the elevated correlation with classical tests of sperm quality, the Comet assay has ample potential for clinical and research purposes in dogs.  相似文献   

Management practices to control premature senescence in Bt cotton     

Muhammad Faisal Bilal  Muhammad Ashfaq Wahid  Amir Shakeel  Andrew French  Muhammad Sarwar 《Journal of plant nutrition》2017,40(14):1978-1992

Commercial cultivation of Bt cotton produced higher boll load which led to stiff inter-original competition for photosynthates, resulting in early cessation of growth (premature senescence) due to more availability of sink and less sources. To overcome this problem, field experiment was conducted during 2011 and 2012 using five treatments of plant growth manipulation viz. no fruiting branch removal (F₁), removal of first fruiting branch (F₂), removal of first and second fruiting branch (F₃), removal of all squares from first fruiting branch (F₄), removal of all squares from first and second fruiting branches (F₅), and three potassium (K) application rates viz. 50 kg ha^?1 (K₁), 100 kg ha^?1 (K₂), and 150 kg ha^?1 (K₃). More nodes above white flower were recorded in F₅, followed by F₃, while minimum were recorded in F₁. Among potassium levels, maximum nodes above white flower were recorded in K₃ followed by K₂ and K₁ during both years of study. Plant height recorded at physiological cutout stage or at maturity stage showed that plants gained more height with removal of all squares from first tosecond fruiting branches with higher potassium dose. Leaf K increased with increasing applied potassium and also with square/branch removal. So early removal of squares/fruiting branches along with higher potassium dose helped in delaying canopy senescence in Bt cotton.  相似文献   

Bayesian zero-inflated predictive modelling of herd-level Salmonella prevalence for risk-based surveillance     

Benschop J  Spencer S  Alban L  Stevenson M  French N 《Zoonoses and public health》2010,57(Z1):60-70

The national control programme for Salmonella in Danish swine herds introduced in 1993 has led to a large decrease in pork-associated human cases of salmonellosis. The pork industry is increasingly focused on the cost-effectiveness of surveillance while maintaining consumer confidence in the pork food supply. Using national control programme data from 2003 and 2004, we developed a zero-inflated binomial model to predict which farms were most at risk of Salmonella. We preferentially sampled these high-risk farms using two sampling schemes based on model predictions resulting from a farm's covariate pattern and its random effect. Zero-inflated binomial modelling allows assessment of similarities and differences between factors that affect herd infection status (introduction), and those that affect the seroprevalence in infected herds (persistence and spread). Both large (producing greater than 5000 pigs per annum), and small herds (producing less than 2000 pigs per annum) were at significantly higher risk for infection and subsequent seroprevalence, when compared with medium sized herds (producing between 2000 and 5000 pigs per annum). When compared with herds being located elsewhere, being located in the south of Jutland significantly decreased the risk of herd infection, but increased the risk of a pig from an infected herd being seropositive. The model suggested that many of the herds where Salmonella was not detected were infected, but at a low prevalence. Using cost and sensitivity, we compared the results of our model based sampling schemes with those under the standard sampling scheme, based on herd size, and the recently introduced risk-based approach. Model-based results were less sensitive but show significant cost savings. Further model refinements, sampling schemes and the methods to evaluate their performance are important areas for future work, and these should continue to occur in direct consultation with Danish authorities.  相似文献   

Avian assemblages in eucalypt forests,plantations and pastures in northern NSW,Australia     

Tina Hsu  Kris French  Richard Major 《Forest Ecology and Management》2010

Eucalypt plantations are expanding rapidly in Australia, and their value for native fauna requires investigation. The relative conservation value of young eucalypt plantations was investigated through assessment of avifauna richness, abundance and composition using transect surveys incorporating point counts in five broad habitat types—dryland forests, riparian forests, dryland plantations, riparian plantations, and riparian pastures (strips of riparian vegetation surrounded by pastures). A total of 73 species were recorded during formal surveys. Species richness and abundance were comparable among all habitat types except dryland plantations, which supported fewer species and in lower numbers. The avifauna assemblage differed according to broad habitat types. Forest habitats (dryland and riparian) harboured more forest- and woodland-dependent species, and a greater abundance of nectarivores and insectivores. Riparian plantations supported a similar number of forest- and woodland-dependent species to forest habitats, but also retained some open-country species. Riparian pastures had the highest cumulative species richness, reflecting a diverse mix of forest- and woodland-dependent birds and open-country species. It was the preferred habitat type for granivores and vertebrate eaters. Dryland plantations were dominated by common species and omnivores, and supported fewer forest- and woodland-dependent birds, insectivores and frugivores compared with other habitat types. The presence of riparian strips increased avifauna diversity and abundance in plantations and pastures to a greater extent than predicted by the proportional area of riparian habitat. The importance of riparian habitats needs to be recognised and incorporated into management policies if biodiversity conservation is to be an objective of plantation establishment.  相似文献   

Response of Thawed Epidi dymal Red Deer Spermatozoa to Increasing Concentrations of Hydrogen Peroxide,and Importance of Individual Male Variability     

AE Domínguez‐Rebolledo  F Martínez‐Pastor  AF Bisbal  JL Ros‐Santaella  O García‐Álvarez  A Maroto‐Morales  AJ Soler  JJ Garde  MR Fernández‐Santos 《Reproduction in domestic animals》2011,46(3):393-403

Oxidative stress represents a challenge during sperm manipulation. We have tested the effect of increasing hydrogen peroxide (H₂O₂) levels on red deer spermatozoa after cryopreservation, and the role of male‐to‐male variation in that response. In a first experiment, eight thawed samples were submitted to 0, 25, 50, 100 and 200 μm H₂O₂ for 2 h at 37°C. Intracellular reactive oxygen species (H₂DCFDA‐CM) increased with H₂O₂ concentration, but we only detected a decrease in sperm function (motility by CASA and chromatin damage by sperm chromatin structure assay) with 200 μm . Lipoperoxidation assessed by the thiobarbituric acid reactive substance (TBARS) method increased slightly with 50 μm H₂O₂ and above. In a second experiment, samples from seven males were submitted to 0 and 200 μm H₂O₂ for 2 h, triplicating the experiment within each male. Males differed at thawing and regarding their response to incubation and H₂O₂ presence. We found that the kinematic parameters reflected male‐to‐male variability, whereas the response of the different males was similar for lipid peroxidation and viability. A multiparametric analysis showed that males grouped differently if samples were assessed after thawing, after incubation without H₂O₂ or after incubation with H₂O₂. Red deer spermatozoa are relatively resilient to H₂O₂ after thawing, but it seems to be a great male‐to‐male variability regarding the response to oxidative stress. The acknowledgement of this individual variability might improve the development of optimized sperm work protocols.  相似文献   

Cardiovascular-renal axis disorder and acute-phase proteins in cats with congestive heart failure caused by primary cardiomyopathy     

Mengmeng Liu  Liza S. Köster  Geoffrey T. Fosgate  Christopher C. Chadwick  Íñigo Sanz-González  Peter David Eckersall  Paul R. Wotton  Anne T. French 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2020,34(3):1078-1090

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Laboratory Handbook on Bovine Mastitis.     

AF Hope 《Australian veterinary journal》2000,78(7):488-488

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Irrigated guayule — Evapotranspiration and plant water stress     

D.A. Bucks  F.S. Nakayama  O.F. French  W.W. Legard  W.L. Alexander 《Agricultural Water Management》1985,10(1):61-79

Natural rubber is a critical agricultural material, and guayule (Parthenium argentatum Gray) is the most promising domestic, agricultural source. A study on guayule was initiated to provide information on the water requirements and plant water stress behavior for this new perennial crop. Measured evapotranspiration averaged 3000, 2410, 2040, 1720, 1470 and 1520 mm, from May 1981 to December 1982, in decreasing order of water applications on the six irrigation treatments from the wettest to the driest. These evapotranspiration values indicated that the water use by guayule can be higher than many former estimates for an arid-type crop. Plant canopy temperatures also showed a progressive increase in plant water stress as irrigation water amounts decreased. The two-fold decrease in evapotranspiration from the wet to dry treatments corresponded to a four-fold increase in plant water stress indices based on remote infrared thermometer measurements. Both the concepts of stress degree days and crop water stress index, evaluated over the entire growing cycle, correlated well with the measured evapotranspiration. Even though the guayule plant can withstand long periods of drought, moisture stress will occur within a relatively short period of time after an irrigation for the guayule crop.  相似文献   

Prevalence, regional distribution and control of blowfly strike in England and Wales.     

N P French  R Wall  P J Cripps  K L Morgan 《The Veterinary record》1992,131(15):337-342

The prevalence and control of blowfly strike in England and Wales was investigated by a postal survey of 2451 sheep farmers, divided into five regions, who were asked about the blowfly seasons of 1988 and 1989. These were important years for the control of blowfly strike because the number of compulsory dips for the control of sheep scab was reduced from two to one in 1989. The response rate was 74.2 per cent. A larger proportion of farmers in the south west and south east reported strike (90 per cent), than in the north of England (60 per cent). The proportion of sheep with strike showed a similar regional variation (0.7 per cent in the north of England to 2.8 per cent in the south west). Dipping was the most common method of blowfly control, followed by tail amputation, dagging, spraying and cyromazine. Twenty per cent of farmers reported reducing the frequency of dipping in 1989, and of those 20 per cent increased the frequency of spraying and 20 per cent used cyromazine.  相似文献