Point Break Research Articles

Formularization Method for Calculating the Breakaway and Break-in Points and the Corresponding Gain of Root Locus Graphs

Break points, break-away and break-in points, are an essential part in root locus technique for single input single output linear invariant control systems. The importance of Break points comes from the fact that at the Break points at least two roots of the characteristic equation of the closed loop control system change their type from real to a complex at the break away point, and from complex to real at break-in point. This change affects the response of the system which can be crucial for some of systems’ applications. The conditions for being a Break point are analysed and a new formulated systematic method for finding the Break points and their corresponding gains is presented. An efficient algorithm was developed and can be solved analytically. There is no mathematical differentiation during calculation, and the algorithm can be programmed easily. The developed algorithm is applicable for any order of transfer function of a linear invariant control system. This method is compared with other common methods to show its merits and effectiveness.

Efficacy and safety of paclitaxel and carboplatin with bevacizumab for the first-line treatment of patients with nonsquamous non-small cell lung cancer (NSCLC): Analyses based on age in the phase III PointBreak and E4599 trials.

8073 Background: A post hoc analysis of NSCLC (pts) ≥70 y in the pivotal E4599 trial found increased adverse events (AEs) and numerically decreased survival benefit associated with bevacizumab (BEV) vs pts <70 y. We evaluated the efficacy and safety of BEV by age in pts in a pooled dataset from the E4599 and PointBreak (PB) trials. Methods: Pts randomized to the PC (paclitaxel and carboplatin ) + BEV arms of E4599 and PB received P 200 mg/m2, C AUC 6, and BEV 15 mg/kg q3w for 6 (E4599) or 4 (PB) cycles; 1 pt in PB received 6 cycles. Eligible pts received maintenance BEV q3w until disease progression or unacceptable toxicity. Overall survival (OS), progression-free survival (PFS), and safety were assessed in pts grouped according to age (<65 y, 65–75 y, 70–75 y, <75 y, and ≥75 y). Pt-level data from the PC + BEV arms of E4599 and PB were pooled and compared with data from pts in the PC-alone arm of E4599. Results: PB and E4599 randomized 467 pts and 434 pts to PC + BEV, respectively. Baseline characteristics were balanced between age groups. OS and PFS hazard ratios (HRs) and increases in grade ≥3 AEs for the pooled pt cohort relative to E4599 PC-alone arm are shown (Table). Outcomes were similar in pts <70 y and ≥70 y, and data from the pooled population were similar to those seen in each individual trial (data not shown). Conclusions: In a pooled exploratory analysis of pt data from E4599 and PB, the statistically significant benefit associated with the addition of BEV to PC appeared consistent across all age groups <75y. Pts ≥75 y receiving BEV had a higher incidence of grade ≥3 AEs relative to PC alone with no statistically significant survival benefit, although an increase in grade ≥3 AEs was observed in all age groups. Clinical trial information: NCT00762034 and NCT00021060. [Table: see text]

The occurrence of grade 4 adverse events and survival outcomes in patients with nonsquamous non-small cell lung cancer receiving bevacizumab with chemotherapy in the phase III PointBreak and AVAiL studies.

e19022 Background: Progression-free survival (PFS) is a key trial end point for clinical practice, as it relates to a change of treatment line. Grade 4 progression-free survival (G4PFS; defined as time from treatment start to the earlier of progressive disease [PD], onset of a G4 adverse event [AE], or death from any cause) is a composite end point incorporating a measure of tolerability to PFS. This post hoc analysis evaluates G4PFS and the effect of G4 AEs on PFS and overall survival (OS) in patients (pts) enrolled in PointBreak (PB) and AVAiL. Methods: Pts in PB were randomized to bevacizumab (BEV) 15 mg/kg q3w with carboplatin and paclitaxel (CP) or pemetrexed (CPem) for ≤4 cycles. Eligible pts received either BEV or BEV + Pem q3w until PD or unacceptable toxicity. Pts in AVAiL received cisplatin and gemcitabine for ≤6 cycles and either placebo or BEV (7.5 or 15 mg/kg) q3w until PD. AEs were graded via NCI-CTCAE v3.0. Kaplan-Meier and Cox model methods were used to estimate medians and hazard ratios (HRs) for PFS, G4PFS, and OS. PFS and OS were also compared in each arm for pts with occurrence of a G4 AE before week 12 of treatment vs those without. Results: Of those receiving BEV, ~30% of AVAiL pts and 38% of PB pts had a G4 AE. Uncomplicated neutropenia was the most common G4 AE in the CP + BEV arm of PB (26%) and in the BEV arms of AVAiL (11%). PFS, G4PFS, and outcomes by G4 AE occurrence are shown (Table). Conclusions: In both the PB and AVAiL trials, median G4PFS was numerically shorter than median PFS. G4 AE occurrence, however, did not affect subsequent PFS or OS in either trial. Clinical trial information: NCT00762034 and NCT00806923. [Table: see text]

Computer-program description. Root-locus plotting by digital computer using operational-array technique

The objective of the paper is to present a general program for computation of the root locus of time-invariant systems. The method adopted for root-locus location is to express the characteristic equation in polynomial form for every chosen value of the static-loop sensitivity; the factorisation then gives the location of the poles. In addition, the breakaway points are also individually computed and graphically superimposed on the already computed and plotted root-locus diagrams. The break points are where the locus departs from the real axis or returns to it; hence the terms breakaway and break-in points, respectively. In more general interpretation, the breakpoints are where two or more root-locus branches come into contact anywhere in the complex plane. The interpretation above is wholly implemented in the program.