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Sun F Usón J Ezquerra J Crisóstomo V Luis L Maynar M 《Veterinary journal (London, England : 1997)》2008,175(2):186-193
Tracheal collapse in dogs is a common respiratory disorder, typically presenting with a history of chronic cough, increasing respiratory difficulties, and episodes of dyspnoea. Medical treatment is the therapy of choice and surgical repair is considered when patients do not respond well. Minimally invasive endotracheal stenting is a promising new therapy under investigation, but there remain significant challenges to overcome potential complications. The purpose of this article is to provide a comparative overview of intra-luminal stenting of the trachea in human and veterinary medicine. The currently available stents and their potential clinical application to the veterinary patient will be discussed. 相似文献
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At the landscape-level Aerial Photograph Interpretation (API) is one of the oldest and most common tools for mapping forest structure. The variety of attributes available for API classifications can produce 100s of different patch types as a basis for mapping landscape mosaics. However, these maps are often difficult to interpret or use for monitoring the impacts of management and natural disturbance. In this study, we demonstrate an approach for quantifying the landscape forest structure described by API data sets. For this purpose we utilised a forest dataset comprising 1197 field plots and API mapping of crown structural characteristics for 773,280 ha of State Forest in Victoria, Australia. Our approach involved: (i) stratification of the landscape into distinct forest communities; (ii) construction of stand-level structural complexity indices for each forest community; (iii) use of stand-level indices of structural complexity to classify API typing into distinct canopy structural classes; (iv) calculation of the distance from each point within a landscape grid to achieve a full complement of canopy structural classes within each forest community. We term our methodology the distance to structural complement (DiSCo) approach, because it identifies the minimum distance to achieve a full complement of structural units within the landscape. We demonstrate the use of these values in mapping landscape structure and their potential for monitoring and modelling the effects of disturbance at this scale, including impacts on heterogeneity, connectivity, individual faunal species and particular forest communities. 相似文献
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Kierzkowski D Nakayama N Routier-Kierzkowska AL Weber A Bayer E Schorderet M Reinhardt D Kuhlemeier C Smith RS 《Science (New York, N.Y.)》2012,335(6072):1096-1099
Although genetic control of morphogenesis is well established, elaboration of complex shapes requires changes in the mechanical properties of cells. In plants, the first visible sign of leaf formation is a bulge on the flank of the shoot apical meristem. Bulging results from local relaxation of cell walls, which causes them to yield to internal hydrostatic pressure. By manipulation of tissue tension in combination with quantitative live imaging and finite-element modeling, we found that the slow-growing area at the shoot tip is substantially strain-stiffened compared with surrounding fast-growing tissue. We propose that strain stiffening limits growth, restricts organ bulging, and contributes to the meristem's functional zonation. Thus, mechanical signals are not just passive readouts of gene action but feed back on morphogenesis. 相似文献
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Martín-Cancho MF Carrasco-Jiménez MS Lima JR Ezquerra LJ Crisóstomo V Usón-Gargallo J 《American journal of veterinary research》2004,65(4):409-416
OBJECTIVE: To evaluate bispectral index (BIS) values in pigs during anesthesia maintained with sevoflurane-fentanyl or propofol-fentanyl as a predictor of changes in hemodynamic parameters and duration of recovery from anesthesia. ANIMALS: 12 pigs. PROCEDURE: Pigs were randomly allocated to undergo 1 of 2 anesthetic regimens. Anesthesia was induced with propofol (2 mg/kg, i.v.); 6 pigs were administered sevoflurane via inhalation (1 minimum alveolar concentration [MAC] at a fresh gas flow rate of 3 L/min; group I), and 6 were administered propofol (11 mg/kg/h, i.v.; group II). All pigs received fentanyl (2.5 mg/kg, i.v., q 30 min). After abdominal surgery, pigs were allowed to recover from anesthesia. Cardiovascular variables and BIS values were recorded at intervals throughout the procedure; duration of recovery from anesthesia was noted. RESULTS: No correlation was established between arterial blood pressure and BIS and between heart rate and BIS. Mean BIS at discontinuation of administration of the anesthetic agent was greater in group-II pigs (65.2 +/- 10.6 minutes) than in group-I pigs (55.8 +/- 2.9 minutes). However, recovery from anesthesia was significantly longer in group II (59.80 +/- 2.52 minutes) than in group I (9.80 +/- 2.35 minutes). CONCLUSIONS AND CLINICAL RELEVANCE: In swine anesthetized with sevoflurane or propofol and undergoing abdominal surgery, the BIS value derived from an electroencephalogram at the end of anesthesia was not useful for predicting the speed of recovery from anesthesia. Moreover, BIS was not useful as a predictor of clinically important changes in arterial blood pressure and heart rate in those anesthetized pigs. 相似文献
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Martín-Cancho MF Lima JR Luis L Crisóstomo V Ezquerra LJ Carrasco MS Usón-Gargallo J 《American journal of veterinary research》2003,64(7):866-873
OBJECTIVE: To evaluate bispectral index (BIS), spectral edge frequency 95% (SEF), and median frequency (MED) in relation to a visual analogue scale (VAS) as indicators of anesthetic depth for various concentrations of sevoflurane and isoflurane in pigs. ANIMALS: 32 pigs. PROCEDURE: Pigs were randomly allocated to 8 groups (4 pigs/group). An electroencephalogram (EEG) was recorded in each conscious pig. Pigs were then anesthetized by use of sevoflurane (n = 16) or isoflurane (16). Agents were administered in oxygen at minimum alveolar concentrations (MACs) of 1, 1.25, 1.5, and 1.75 MAC in a randomized order. End-tidal sevoflurane and isoflurane concentrations were maintained for 30 minutes, after which an EEG was recorded for 5 minutes; BIS, SEF, and MED were then calculated. Anesthetic depth was evaluated by use of the VAS. Cardiovascular and EEG responses to nociceptive stimuli were evaluated for each anesthetic agent. RESULTS: BIS decreased significantly for the various concentrations of each anesthetic. At equivalent MACs, BIS values were significantly higher during sevoflurane-induced anesthesia than during isoflurane-induced anesthesia. Values of MED and SEF decreased significantly from basal values to 1 MAC of sevoflurane and isoflurane. For both agents, there was good correlation between VAS scores and BIS values and between VAS scores and SEF values. CONCLUSIONS AND CLINICAL RELEVANCE: BIS was useful for predicting changes in anesthetic depth at clinical dosages of inhalant anesthetics. Values of BIS, SEF, and MED were significantly higher during anesthesia induced by administration of sevoflurane than during anesthesia induced by administration of isoflurance at equivalent MACs. 相似文献
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Canberra, Australia's national capital, is a planned city established on grazing lands in the southern tablelands of New South Wales. Over the past nine decades it has grown into a garden city of 300,000 people. Landscaping was an early priority as much of the chosen site for the city was a treeless plain. Major tree planting began in the 1920's and today the urban forest on public lands contains 400,000 trees from over 200 species in streets and parklands. The species used have changed over time with exotic deciduous trees and conifers dominating early plantings. By the 1970's native species, mostly eucalypts, were planted. Today fewer species comprising an equal mix of native and exotics are used. Trees in the earlier plantings are now mature and given the harshness of the local climate many will come to the end of their ‘safe life’ in the early decades of this century. This provides new challenges for urban tree managers as to how to effect tree replacement that is aesthetically pleasing, ecologically sound and socially acceptable. To assist in this planning a tree data base and modeling system has been assembled. This system – Decision Information System for Managing Urban Trees or DISMUT – facilitates the development of forest-level management programs by allowing the projection of change and work requirements that the result from historical and current plantings over the entire urban forest. 相似文献
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