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Median Rate (median + rate)
Selected AbstractsMixing calcium chloride with commercial fungicide formulations results in very slow penetration of calcium into apple fruitsJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 3 2004Thomas K. Schlegel Abstract Foliar applications of calcium salts are usually combined with fungicides. In the years 2002 and 2003, it was tested if this practice assures high rates of penetration of calcium. Amounts that penetrated in 24 h were measured at 20,°C using 45CaCl2. To ensure maximum penetration rates, humidity was maintained at 100,%. Sample size was 40 to 50 fruits, and data were presented as box plots because distribution of data was not normal. Median rates of penetration of CaCl2, measured with mixtures of fungicides and CaCl2 at 5 or 10 g l,1, respectively, were very slow, and amounted to only a few percent of the dose applied. Rates were a little higher with very young fruits (55 days after full bloom, DAFB). Adding alkyl polyglycoside surfactants at 0.2 g l,1 significantly decreased surface tensions, and increased rates of penetration by up to 15-fold. Still, total penetration of CaCl2 rarely exceeded 20,% of the dose applied (median penetration), even in the presence of an additional surfactant. In all treatments, outliers with 60 to 100,% penetration in 24 h occurred, and this was attributed to penetration into lenticels. This is expected to result in unequal concentrations of calcium in fruits, especially in the sub-epidermal layers. Addition of a suitable surfactant to mixtures of fungicides with CaCl2 is strongly recommended as it enhances wetting and greatly increases penetration rates of CaCl2. Mischen von Calciumchlorid mit Fungiziden resultiert in einer sehr langsamen Penetration von Calcium in Apfelfrüchte Zur Blattdüngung werden Calciumsalze meist mit Fungiziden gemischt. Es wurde untersucht, ob diese Praxis hohe Penetrationsraten für das ausgebrachte Calciumsalz gewährleistet. Die Penetration wurde mit 45CaCl2 bei 20,°C gemessen. Die Luftfeuchte betrug 100,%, so dass maximale Penetrationsraten erzielt wurden. Der Stichprobenumfang betrug 40 bis 50 Früchte. Die Ergebnisse werden als Box-Plots präsentiert, weil die Verteilung der Daten nicht normal war. Bei Mischungen von CaCl2 (5 bis 10 g l,1) mit Fungiziden betrugen die Mediane der Penetrationsraten von CaCl2 nur einige Prozent. Bei sehr jungen Früchten (55 Tage nach Vollblüte, DAFB) waren die Raten etwas höher als bei älteren. Durch Zugabe von Alkyl-Polyglykosiden (0.2 g l,1) wurden die Oberflächenspannungen der Lösungen verringert und die Penetration von Calcium bis zu 15fach erhöht. Trotzdem betrug die Penetration in 24 h nur selten mehr als 20,% der Dosis. In allen Behandlungen wurden Ausreißer beobachtet, bei denen die Penetration in 24 h 60 bis 100,% der Dosis betrug. Das wurde auf Infiltration von Lentizellen zurückgeführt. Dadurch dürfte die Calciumkonzentration in Früchten nach Spritzung mit CaCl2 nicht homogen sein, besonders nicht in den subepidermalen Schichten. Die Zugabe eines geeigneten Netzmittels zu Mischungen von Fungiziden mit CaCl2 wird empfohlen. Dadurch wird die Benetzung der Früchte verbessert, und die Penetrationsraten werden erhöht. [source] Mortality dynamics and population regulation in Bemisia tabaciENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 2 2005Steven E. Naranjo Abstract Natural mortality is an important determinant of the population dynamics of a species, and an understanding of mortality forces should aid in the development of better management strategies for insect pests. An in situ, observational method was used to construct cohort-based life tables for Bemisia tabaci (Gennadius) Biotype B (Homoptera: Aleyrodidae) over 14 generations on cotton in central Arizona, USA, from 1997 to 1999. In descending order, median marginal rates of mortality were highest for predation, dislodgment, unknown causes, egg inviability, and parasitism. The highest mortality occurred during the 4th nymphal stadium, and the median rate of immature survival over 14 generations was 6.6%. Predation during the 4th nymphal stadium was the primary key factor. Irreplaceable mortality was highest for predation and dislodgment, with the absence of these mortality factors leading to the greatest increases in estimated net reproduction. There was little evidence of direct or delayed density-dependence for any mortality factor. Wind, rainfall, and predator densities were associated with dislodgment, and rates of predation were related to densities of Geocoris spp., Orius tristicolor (White), Chrysoperla carnea s.l. Stephens, and Lygus hesperus Knight. Simulations suggest that immigration and emigration play important roles in site-specific dynamics by explaining departures from observed population trajectories based solely on endogenous reproduction and mortality. By a direct measurement of these mortality factors and indirect evidence of adult movement, we conclude that efficient pest management may be best accomplished by fostering greater mortality during the 4th stadium, largely through a conservation of predators and by managing immigrating adult populations at their sources. [source] Usefulness of follow-up after pancreatoduodenectomy for carcinoma of the ampulla of VaterHPB, Issue 2 2007LAURENCE CHICHE Abstract Background: The prognosis for carcinoma of the ampulla of Vater (CAV) is better than for pancreatic cancer. The 5-year survival median rate after resection of CAV is 45%, but late recurrences remain possible. Several survival factors have been identified (lymph nodes, perineural invasion), but few data are available on the type of recurrences, their impact and their management. Patients and methods: A total of 41 patients treated by pancreatoduodenectomy (PD) for CAV from 1980 to 2003 were studied retrospectively. Patient selection, long-term survival recurrence rate and recurrence treatment were reviewed. Univariate and multivariate proportional hazards analysis were conducted on this series. Results: The mean follow-up was 48 months. Five-year survival was 62.8%. Eleven patients had recurrences (6,67 months). Recurrence was associated with time to all-causes death (hazard ratio [HR] 4.3, p=0.003). Factors predictive of recurrence were perineural invasion (HR 5.3, p=0.02), lymph node invasion (HR 5.3, p=0.02) and differentiation (HR 0.2, p=0.05). Three patients underwent surgical R0 treatment of their recurrences. Two who presented with solitary liver metastasis are alive and disease-free. Conclusions: Recurrence represents a serious threat in the prognosis of CAV after surgery. Some of these recurrences, in particular liver metastases, are accessible for a curative treatment. This finding supports the usefulness of a close and long-term follow-up after surgery to improve survival of patients with CAV, especially in the group of patients with a good prognosis. [source] Rapid Ventricular Pacing for Catheter Interventions in Congenital Aortic Stenosis and Coarctation: Effectiveness, Safety, and Rate Titration for Optimal ResultsJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 1 2010CHETAN MEHTA M.B.B.S. Introduction: Infants and children with congenital aortic stenosis and coarctation of the aorta can be treated by catheter intervention. There are several pharmacological and mechanical techniques described to overcome the balloon movement; none, however, have proved entirely satisfactory. An alternative method to achieve balloon stability is the use of rapid ventricular pacing. We describe our experience with titrating the pacing rate and the use of this technique. Methods: A retrospective review of database was performed, to identify patients who underwent transcatheter intervention with rapid ventricular pacing. Invasive systemic pressures were documented with a catheter in the aorta. Rapid ventricular pacing was initiated at the rate of 180 per minute and increased by increments of 20 per minute to a rate required to achieve a drop in systemic pressure by 50% and a drop in pulse pressure by 25%. The balloon was inflated only after the desired pacing rate was reached. Pacing was continued until the balloon was completely deflated. Results: Thirty patients were identified, 29 of whom had interventions with rapid ventricular pacing. Balloon valvuloplasty of aortic valve was performed on 25 patients while 4 patients had stenting for coarctation by this technique. The rate of ventricular pacing required ranged from 200 to 260 per minute with a median rate of 240. Balloon stability at the time of intervention was achieved in 27 patients. Conclusion: Rapid ventricular pacing is a safe and effective method to provide transient decrease in cardiac output at the time of transcatheter interventions to achieve balloon stability. (J Interven Cardiol 2010;23:7,13) [source] | ||||||||||