A mathematical model linking tree sap flow dynamics to daily stem diameter fluctuations and radial stem growth     

Steppe K  De Pauw DJ  Lemeur R  Vanrolleghem PA 《Tree physiology》2006,26(3):257-273

To date, models for simulating sap flow dynamics in individual trees with a direct link to stem diameter variation include only the diameter fluctuation driven by a change in stem water storage. This paper reports results obtained with a comprehensive flow and storage model using whole-tree leaf transpiration as the only input variable. The model includes radial stem growth based on Lockhart's equation for irreversible cell expansion. It was demonstrated that including growth is essential to obtaining good simulation results. To model sap flow dynamics, capacitance of storage tissues was assumed either constant (i.e., electrical analogue approach) or variable and dependent on the water content of the respective storage tissue (i.e., hydraulic system approach). These approaches resulted in different shapes for the desorption curve used to calculate the capacitance of storage tissues. Comparison of these methods allowed detection of specific differences in model simulation of sap flow at the stem base (F(stem)) and stem diameter variation (D). Sensitivity analysis was performed to select a limited subset of identifiable parameters driving most of the variability in model predictions of F(stem) and D Both the electrical analogue and the hydraulic system approach for the flow and storage model were successfully calibrated and validated for the case of a young beech tree (Fagus sylvatica L.). Use of an objective model selection criterion revealed that the flow and storage model based on the electrical analogue approach yielded better predictions.  相似文献   

An inconvenient truth about xylem resistance to embolism in the model species for refilling <Emphasis Type="Italic">Laurus nobilis</Emphasis> L.     

Laurent J. Lamarque  Déborah Corso  José M. Torres-Ruiz  Eric Badel  Timothy J. Brodribb  Régis Burlett  Guillaume Charrier  Brendan Choat  Hervé Cochard  Gregory A. Gambetta  Steven Jansen  Andrew King  Nicolas Lenoir  Nicolas Martin-StPaul  Kathy Steppe  Jan Van den Bulcke  Ya Zhang  Sylvain Delzon 《Annals of Forest Science》2018,75(3):88

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Allergen‐specific immunotherapy prescription patterns in veterinary practice: a US population‐based cohort study          下载免费PDF全文

Kathy Chu Tater  William Elliott Cole  Paul David Pion 《Veterinary dermatology》2017,28(4):362-e82

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Fournier's gangrene in a cat     

Danielle E. Berube  DVM  ; Megan F. Whelan  DVM  DACVECC  ; Kathy C. Tater  DVM  DACVD    Kiko E. Bracker  DVM  DACVECC 《Journal of Veterinary Emergency and Critical Care》2010,20(1):148-154

Objective – To describe the clinical course of a cat diagnosed with Fournier's gangrene.
Case Summary – A 2-year-old castrated male cat was presented to an emergency hospital for evaluation of acute onset of lethargy, mucoid anal discharge, and fever. During hospitalization, with provision of supportive care, an area of necrotizing fasciitis around the prepuce and anus developed and surgical debridement was performed. Severe sepsis developed secondary to the necrotizing fasciitis and the cat was eventually euthanized.
New Information Provided – The purpose of this report is to document the first case of Fournier's gangrene in a cat that presented for mucoid anal discharge, lethargy, and mild ataxia, and to alert emergency clinicians to this disease process. Early detection of the disease with prompt, aggressive supportive care and surgical debridement is necessary for successful treatment.  相似文献   

Response of woodpeckers to changes in forest health and harvest: Implications for conservation of avian biodiversity     

Mark C. Drever  Kathy Martin 《Forest Ecology and Management》2010

Woodpeckers (family Picidae) merit specific monitoring and management efforts, both as keystone/facilitator species and as indicators of forest condition. Recent studies indicated that species richness of woodpeckers was correlated with richness of all forest birds, thus suggesting potential exists for management practices that can address needs of woodpeckers in particular and other forest birds in general. We used data from a long-term study (1995–2008) from forest sites in the interior of British Columbia to evaluate how abundances of seven woodpecker species varied with habitat variables previously identified as associated with forest bird richness. We found that tree species richness had either a neutral or positive effect on the abundance of all woodpecker species, whereas abundances of most woodpecker species tended to be lower in stands with high densities of lodgepole pine. Abundances of most woodpecker species were positively correlated with density of beetle-killed pines. Relative to control sites, higher densities of most woodpecker species were found at harvested sites where most trembling aspen and large Douglas-fir trees had been retained. Therefore, management strategies that favour a mixture of tree species, with particular attention to retention of aspen, should safeguard populations of most woodpecker species. Abundances of individual woodpecker species were weakly but positively inter-correlated before the beetle outbreak, and less so during and post-outbreak. It thus appears that no strong trade-offs exist among woodpecker species. These results, combined with previously identified positive correlations between woodpecker and forest bird richness, indicate woodpeckers can be managed as a suite for the purpose of managing avian biodiversity as a whole.  相似文献   

Fruit and vegetables are similarly categorised by 8-13-year-old children     

Sepulveda KK  Beltran A  Watson K  Baranowski T  Baranowski J  Islam N  Missaghian M 《Public health nutrition》2009,12(2):175-187

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Correlation between loss of efficacy of macrocyclic lactone heartworm anthelmintics and P-glycoprotein genotype     

Bourguinat C  Keller K  Blagburn B  Schenker R  Geary TG  Prichard RK 《Veterinary parasitology》2011,176(4):374-381

Macrocyclic lactone (ML) molecules have been used for heartworm control for more than 25 years. However, in recent years, there have been reports of loss of efficacy of ML heartworm preventatives against Dirofilaria immitis in some locations in the United States. Macrocyclic lactone resistance is a common problem in nematode parasites of livestock, and more recently, evidence of ivermectin resistance has been reported in the human filarial nematode Onchocerca volvulus. In this study, four D. immitis sample groups from the United States with different treatment histories were investigated for evidence of ML-driven genetic selection. DNA from individual adult worms and microfilariae was amplified by polymerase chain reaction to investigate a gene encoding a P-glycoprotein, a protein class known to be involved in ML pharmacology. A significant correlation of a GG-GG genotype with ivermectin response phenotype was found. Moreover, a significant loss of heterozygosity was found in a low responder group; loss of heterozygosity is commonly seen in loci when a population has been under selection. Further studies are required to confirm ML resistance in heartworm populations. However, the genetic changes observed in this study may be useful as a marker to monitor for ML resistance in D. immitis.  相似文献   

Parent's responses to nutrient claims and sports celebrity endorsements on energy-dense and nutrient-poor foods: an experimental study     

Dixon H  Scully M  Wakefield M  Kelly B  Chapman K  Donovan R 《Public health nutrition》2011,14(6):1071-1079

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Use of enzyme-linked immunosorbent assay to detect potato leafroll virus in field grown potato,cv. Russet Burbank     

Kathy L. Flanders  David W. Ragsdale  Edward B. Radcliffe 《American Journal of Potato Research》1990,67(9):589-602

Use of enzyme-linked immunosorbent assay (ELISA) in detecting potato leafroll infections in field grown potato, cv. Russet Burbank, was studied from 1986 to 1988 at Rosemount, Minnesota. The objective was to determine relative reliability of current season foliage ELISA, tuber tissue ELISA, and tuber progeny foliage ELISA. Serological tests were most accurate when foliage of tuber progenies was tested. ELISA underestimated total leafroll infection when current season foliage from the inoculated plant was used, in those plants inoculated during late tuber bulking stage. Current season foliage ELISA tests using newly expanded terminal leaflets were more reliable than were tests using older leaflets. Leafroll infection was detected in the current season foliage and tuber progenies (tuber tissue as well as tuber progeny foliage) of some plants seven days after inoculation. Most current season foliage infections were detected by day 14–28 depending on year. Differences among years were most likely caused by variation in quality of virus source plants and numbers of vectors used in inoculation. ELISA tests on tuber tissue were almost as effective as ELISA tests on tuber progeny foliage in detecting potato leafroll 20 days after inoculation, but ELISA on tuber tissue substantially underestimated infection if plants were sampled earlier. Maximum percent tuber infection occurred 20 days or more after inoculation. Movement of the virus from the inoculated stem to other stems decreased with increased plant age at inoculation. Percent infected tubers declined with increased plant age at inoculation. Action thresholds developed for aphids in managing potato leafroll virus should take into account the temporal change in percent infected tubers.  相似文献   

Cavity and bark nesting bird response to partial cutting in Northern conifer forests     

C. Lisa Mahon  J. Douglas Steventon  Kathy Martin 《Forest Ecology and Management》2008

We investigated whether partial cutting used to mimic small-scale natural disturbances could maintain cavity and bark nesting breeding birds. We assessed changes in the relative abundance of cavity nesting birds in two intensities of partial cutting, compared to uncut and clearcut stands, 9 years post-treatment. We then examined the relationship between forest structure and nesting abundance (stand scale) and compared characteristics of used nest and forage trees to unused trees (tree scale). The relative abundance of most species was highest in either heavy removal or light removal treatments 9 years post-harvest. Brown creepers were most abundant in uncut, and red-breasted sapsuckers were most abundant in clearcut and heavy removal treatments. The proportion of deciduous trees and the density of dead trees were the best predictors of nest abundance. Individual nest tree use was predicted by the presence of large deciduous trees with broken tops and early to advanced stages of decay. Forage tree use was predicted by the presence of large conifer trees in advanced stages of decay. To maintain breeding habitat for cavity nesters, we suggest that forest managers retain the specific structural attributes required for nesting, but also the diverse forest conditions required for foraging.  相似文献