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Relating Simazine Performance to Irrigation Management
- Alfredo Dasilva, Cindy Garretson, John Troiano, Gary Ritenour, Charles Krauter
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- Journal:
- Weed Technology / Volume 17 / Issue 2 / June 2003
- Published online by Cambridge University Press:
- 20 January 2017, pp. 330-337
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Although water is crucial to the performance of preemergence herbicides, pesticide performance has rarely been related to irrigation management. This 2-yr study investigated the effect that amount of irrigation water applied had on activity of simazine. Three rates of simazine at 0, 1.12, and 2.24 kg/ha were applied to a 3-yr-old nectarine orchard that was irrigated with microsprinklers. The performance of simazine was compared between irrigation treatments initially targeted to provide water at 110 (efficient) and 175% (overwatered) of crop water requirements. Simazine effectiveness was based on the survival of oat and cucumber plants that were seeded at 0, 14, 28, 56, and 84 d after herbicide application. A longer time interval to 50% survival indicated prolonged herbicidal activity. Results were consistent between years in that simazine's performance was consistently greater in efficient irrigation treatments. The greatest increases were measured at the higher simazine application rate (2.24 kg/ha); overall averages for the length of time to reach 50% survival for cucumber were 50 and 23 d and for oats were 55 and 15 d for efficient and overwatered irrigation treatments, respectively. Use of an efficient irrigation management technique could have enhanced simazine's performance through a decreased leaching of residues from the weed root zone or less chemical or biological degradation (or both). Adoption of efficient irrigation management has been identified as a best management practice to mitigate leaching of pesticide residues to groundwater in coarse soils in California. This study indicates that efficient irrigation improves simazine performance and that both factors, pesticide application and irrigation management, should be considered when developing a weed management system.
Chapter 145 - Inflatable penile prosthesis
- from Section 26 - Urologic Surgery
- Edited by Michael F. Lubin, Emory University, Atlanta, Thomas F. Dodson, Emory University, Atlanta, Neil H. Winawer, Emory University, Atlanta
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- Book:
- Medical Management of the Surgical Patient
- Published online:
- 05 September 2013
- Print publication:
- 15 August 2013, pp 811-812
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Summary
In 1998, the introduction of sildenafil allowed erectile dysfunction to gain public recognition and acknowledgment among men. Subsequently, more and more patients have become comfortable in seeking treatment for this condition. Once erectile dysfunction becomes refractory to medical measures, motivated patients may consider undergoing surgical placement of an inflatable penile prosthesis (IPP). Since its introduction in 1973, the IPP has undergone many revisions and improvements. These changes have allowed for easier surgical insertion, decreased complications, and patient and partner satisfaction rates consistently greater than 90%.
The inflatable penile prosthesis typically comes in two forms: two-piece and three-piece. The difference between the two is that the latter contains a fluid reservoir within the pelvis, which is typically placed below the rectus abdominis fascia. A manually operated internal pump allows for the movement of fluid between the reservoir and cylinders to create an erect penile state. The reservoir within the three-piece IPP allows for greater changes in penile size when compared with the two-piece model, which relies on the movement of much smaller amounts of fluid from the base of the cylinders to the distal ends. In both cases, the penile cylinders are placed within the paired corpora cavernosa, and the pump is located within the base of the scrotum. There are two surgical approaches for placing the implant: infrapubic and penoscrotal. It is currently estimated that ~85% of IPPs are placed penoscrotally, with an occasional abdominal counter-incision for placement of the reservoir. The principle of the IPP is that a patient can squeeze the scrotal pump to allow fluid to fill the penile cylinders, creating tumescence for successful coitus. At the conclusion of intercourse, the release mechanism on the pump is pushed and fluid exits the cylinders, allowing for detumescence. While the basic principles of the device are similar, the specific components depend on the manufacturer of the prosthesis.
Effects of positive and negative life events on time to depression onset: an analysis of additivity and timing
- E. Frank, X. M. Tu, B. Anderson, C. F. Reynolds III, J. F. Karp, A. Mayo, A. Ritenour, D. J. Kupfer
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- Journal:
- Psychological Medicine / Volume 26 / Issue 3 / May 1996
- Published online by Cambridge University Press:
- 09 July 2009, pp. 613-626
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While the relationship of life events to depression onset has occupied researchers for almost a quarter of a century, few studies have attempted to account for either the temporal patterning of events relative to episode onset, or, the effect of multiple events in a study period. In this report, we attempt to address the issues of timing of events, multiple events (both positive and negative) and multiple aspects (both positivity and negativity) of single events on latency time to depression onset, while simultaneously accounting for possible decay in the effects of events over time. We use the proportional hazards approach to model the effects of life events and consider modelling the change in impact of events with the passage of time.
After interviewing 142 recurrent unipolar patients using the Life Events and Difficulties Schedule, we rated severity and positivity of life events reported during the 6-month period prior to onset. As we hypothesized, additional life events occurring after an initial provoking agent level event significantly alter the risk of illness onset. Additional severely threatening events decrease the time to onset, but positive events do not appear to delay onset. Interestingly, seemingly neutral events had a highly significant effect in shortening the time to onset. We note the many limitations imposed on the interpretation of these findings related to the selected group of subjects studied and encourage those who have more generalizable data to apply these methods of analysis.