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131.
The demand for more effective leadership is heard throughout the health professions. Modern concepts of leadership differ from the traditional definition of a charismatic individual leader. Historically, leadership has been vested in positions, while today leadership is seen as a role one moves continuously into and out of, depending on the circumstance. Leadership ideas have evolved so that newer characteristics of leaders include being a team builder; possessing creative and strategic thinking skills; demonstrating honesty and integrity; and having the ability to motivate others to action. This article discusses some of the history of leadership, current thoughts on attributes of effective leaders, and the differences and similarities between leaders and managers; identifies selected teachable leadership tools; and describes various styles and purposes of existing leadership programs. 相似文献
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133.
A Eyles D Worledge P Sands ML Ottenschlaeger SC Paterson D Mendham AP O'Grady 《Tree physiology》2012,32(8):1008-1020
Early weed control may improve the growth of forest plantations by influencing soil water and nutrient availability. To understand eucalypt growth responses to weed control, we examined the temporal responses of leaf gas-exchange, leaf nitrogen concentration (N) and water status of 7-month-old Eucalyptus globulus L. trees in a paired-plot field trial. In addition, we monitored the growth, leaf N and water status of the competing vegetation in the weed treatment. By the end of the 11-month experiment, complete weed control (WF treatment) of largely woody competitors increased the basal diameter of E. globulus by 14%. As indicated by pre-dawn water potentials of >?-?0.05 MPa, interspecies competition for water resources was minimal at this site. In contrast, competition for N appeared to be the major factor limiting growth. Estimations of total plot leaf N (g m(-2) ground) showed that competing vegetation accounted for up to 70% of the total leaf N at the start of the trial. This value fell to 15% by the end of the trial. Despite increased leaf N(area) in WF trees 5 months after imposition of weed control, the photosynthetic capacity (A(1500)) of E. globulus was unaffected by treatment suggesting that the growth gains from weed control were largely unrelated to changes in leaf-level photosynthesis. Increased nutrient availability brought about by weed control enabled trees to increase investment into leaf-area production. Estimates of whole-tree carbon budget based on direct measurements of dark respiration and A(1500) allowed us to clearly demonstrate the importance of leaf area driving greater productivity following early weed control in a nutrient-limited site. 相似文献
134.
The p38 mitogen-activated protein kinases (MAPKs) are members of discrete signal transduction pathways that have significant regulatory roles in a variety of biological processes, depending on the cell, tissue and organ type. p38 MAPKs are involved in inflammation, cell growth and differentiation and cell cycle. In the female reproductive system, p38 MAPKs are known to regulate various aspects of the reproductive process such as mammalian estrous and menstrual cycles as well as early pregnancy and parturition. p38 MAPKs have also been implicated in alterations and pathologies observed in the female reproductive system. Therefore, pharmacologic modulation of p38 MAPKs, and inter-connected signaling pathways (e.g., estrogen receptor signaling, c-fos, c-jun), may influence reproductive physiology and function. This article provides a critical, comparative review of available data on the roles of p38 MAPKs in the mammalian female reproductive system and in reproductive pathophysiology in humans and preclinical species. We first introduce fundamental differences and similarities of the mammalian female reproductive system that should be considered by toxicologists and toxicologic pathologists when assessing the effects of new pharmacologic agents on the female reproductive system. We then explore in detail the known roles for p38 MAPKs and related molecules in female reproduction. This foundation is then extended to pathological conditions in which p38 MAPKs are thought to play an integral role. 相似文献
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137.
M. F. B. Dale M. S. Phillips 《European journal of plant pathology / European Foundation for Plant Pathology》1995,101(1):51-56
Fourteen cultivars generally regarded as uniformly susceptible toGlobodera pallida Pa 2/3 were assessed in plastic closed containers for degree of susceptibility and also for root and sprouting characteristics. The material was assessed by scoring degree of sprouting before planting and number of cysts and root growth at the end of experiment at intervals from the time of initial dormancy break through to prolific sprouting. Using covariate analyses, it was found that the degree of root development, particularly in the earlier assessments, significantly influenced the degree of cyst development and so the perceived levels of susceptibility/resistance. Having taken account of root growth characters, significant differences between the cultivars with regard to nematode multiplication were still evident. The implications of the results are discussed in relation to potato breeding and nematological studies. 相似文献
138.
Neil D. Havis Dale R. Walters Sally A. Foster William P. Martin Fiona M. Cook David J. Robins 《Pest management science》1994,41(1):61-69
The putrescine analogue. (E)-1,4-diaminobut-2-ene (E-BED), synthesized as the dihydrochloride salt, controlled five economically important crop pathogens, Erysiphe qraminis DC f.sp. hordei Marchal. Uromyces viciae-fabae (Pers.) Schroet, Botrytis fabae Sardina, Podosphaera leucotricha (Ell. & Ev.) Salm. and Phytophthora infestans (Mont) De Bary. The Z-isomer. Z-BED. was also fungicidal, although less so than E-BED. Post-inoculation treatment with E-BED gave greater control of powdery mildew infection on barley and rust and chocolate spot on broad bean than did pre-inoculation application. It was also effective in vitro against Botrytis cinerea Pers. ex Fr., Pyricularia oxyzae Br. & Cav. and Pyrenophora avenae Ito & Karibay. When P. avenae was grown in the presence of E-BED dihydrochloride at 81·5 mg litre?1, growth was reduced by 58% and there were significant reductions in soluble ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (AdoMetDC) activity. These changes were accompanied by a sevenfold increase in putrescine concentration, a 60% increase in spermine concentration and a 32% reduction in spermidine concentration within the fungal tissue. 相似文献
139.
Desiree L. Little David W. Ladner Dale L. Shaner Richard D. Ilnicki 《Pest management science》1994,41(3):171-185
Quantitative structure-activity relationships (QSAR) were developed between the physicochemical parameters of the 5-substituent of a series of analogs of the imidazolinone herbicide, imazapyr, and root absorption, translocation, inhibition of acetohydroxyacid synthase (AHAS), and herbicidal activity of the analogs. An optimum substituent lipophilicity (π = 1.85–2–3) for root absorption was identified for corn (Zea mays L.) and sunflower (Helianthus annuus L.). Translocation from roots to shoots was greatest for those analogs having either highly nonpolar or highly polar 5-substituents, indicating that both symplastic and apopiastic mechanisms may be functioning. In addition, translocation from roots was positively correlated with electron-withdrawing parameters of the 5-substituent, and a possible mechanism governing this relationship is discussed. Modeling in vitro AHAS inhibition was not successful, but models were developed for herbicidal activity as measured in an Arabidopsis thaliana (L.) Hevnh. bioassay. The whole-plant models described an optimum substituent lipophilicity (π = 0 71) which probably reflected the influence of this parameter on the component processes of absorption and translocation. Whole-plant activity was also greater for analogs having electron-donating 5-substituents; this result suggests that electron donation may be important for metabolism, or more likely, for AHAS inhibition. 相似文献
140.
Bertelsen MF Mosley CA Crawshaw GJ Dyson DH Smith DA 《Journal of the American Veterinary Medical Association》2005,227(4):575-578
OBJECTIVE: To determine the minimum alveolar concentration (MAC) of sevoflurane and assess the sevoflurane-sparing effect of coadministration of nitrous oxide in mechanically ventilated Dumeril monitors (Varanus dumerili). DESIGN: Prospective crossover study. ANIMALS: 10 healthy adult Dumeril monitors. PROCEDURE: Anesthesia was induced with sevoflurane in 100% oxygen or sevoflurane in 66% nitrous oxide (N2O) with 34% oxygen, delivered through a face mask. Monitors were endotracheally intubated, and end-tidal and inspired isoflurane concentrations were measured continuously; MAC was determined by use of a standard bracketing technique. An electrical stimulus (50 Hz, 50 V) was delivered to the ventral aspect of the tail as the supramaximal stimulus. A blood sample for blood gas analyses was collected from the ventral coccygeal vessels at the beginning and end of the anesthetic period. An interval of at least 7 days was allowed to elapse between treatments. RESULTS: The MAC +/- SDs of sevoflurane in oxygen and with N2O were 2.51 +/- 0.46% and 1.83 +/- 0.33%, respectively. There was a significant difference between the 2 treatments, and the mean MAC-reducing effect of N2O was 26.4 +/- 11.4%. Assuming simple linear additivity of sevoflurane and N2O, the MAC for N2O was estimated to be 244%. No significant differences in blood gas values--with the predictable exception of oxygen pressure--were detected between the 2 groups. CONCLUSIONS AND CLINICAL RELEVANCE: The MAC of sevoflurane in Dumeril monitors is similar to that reported for other species. The addition of N2O significantly decreased the MAC of sevoflurane in this species. 相似文献