Evaluation of Brey's production/biomass model on the basis of along-term data set on a clam population

The Brey model is one of the most frequently used methods to obtain a quick estimate of the secondary production (P) of an area. It is based on an empirical relationship between the production/biomass (P/B) ratio and the (annual) mean weight (W) of the individuals of a population. Estimates of P/B by this model are frequently obtained by using only single measurements of W and B, thus circumventing tedious efforts required by conventional methods. The obtained P values of communities are sums of estimates made for individual species. Any constraints of the model can be fully understood only by evaluating it for single-species populations. Using an extensive data set obtained by monitoring a population of the bivalve Macoma balthica for 33 yr, we evaluated the model by comparing Brey model estimates of P and P/B with direct annual estimates. We corroborate the basis of the model by presenting a significant relationship between observed annual values of W and P/B. The model satisfactorily predicted P when late-winter (but not late-summer) assessments of W and B were used. The model underestimated P/B in the years with high mortality rates (Z), whereas it overestimated P/B in almost all other years. Z values were a better basis for predictions of P/B than Wvalues. The model could predict P/B well on the exclusive basis of W due to the significant correlation between W and Z (low Z values resulted in older and thus heavier individuals). Multi-year averages of model-predicted and observed P/B estimates were similar only when predictions were based on late-winter or annual (not on summer) estimates of W and B. In conclusion, the model cannot be recommended for precise and unbiased P estimates in a single species when no more than a once-only assessment of Wand B is available

Impact of employee motivation on passenger satisfaction levels – A case study in the state of Karnataka (India)

Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne

Effect of neoadjuvant chemoradiotherapy on health-Related quality of life in esophageal or junctional cancer: Results from the randomized CROSS trial

Purpose To compare pre-agreed health-related quality of life (HRQOL) domains in patients with esophageal or junctional cancer who received neoadjuvant chemoradiotherapy (nCRT) followed by surgery or surgery alone. Secondary aims were to examine the effect of nCRT on HRQOL before surgery and the effect of surgery on HRQOL. Patients and Methods Patients were randomly assigned to nCRT (carboplatin plus paclitaxel with concurrent 41.4-Gy radiotherapy) followed by surgery or surgery alone. HRQOL was measured using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire–Core 30 (QLQ-C30) and –Oesophageal Cancer Module (QLQ-OES24) questionnaires pretreatment and at 3, 6, 9, and 12 months postoperatively. The nCRT group also received preoperative questionnaires. Physical functioning (PF; QLQ-C30) and eating problems (EA; QLQ-OES24) were chosen as predefined primary end points. Predefined secondary end points were global QOL (GQOL; QLQ-C30), fatigue (FA; QLQ-C30), and emotional problems (EM; QLQ-OES24). Results A total of 363 patients were analyzed. No statistically significant differences in postoperative HRQOL were found between treatment groups. In the nCRT group, PF, EA, GQOL, FA, and EM scores deteriorated 1 week after nCRT (Cohen’s d: 20.93, P, .001; 0.47, P, .001; 20.84, P, .001; 1.45, P, .001; and 0.32, P = .001, respectively). In both treatment groups, all end points declined 3 months postoperatively compared with baseline (Cohen’s d: 21.00, 0.33, 20.47, 20.34, and 0.33, respectively; all P, .001), followed by a continuous gradual improvement. EA, GQOL, and EM were restored to baseline levels during follow-up, whereas PF and FA remained impaired 1 year postoperatively (Cohen’s d: 0.52 and 20.53, respectively; both P, .001). Conclusion Although HRQOL declined during nCRT, no effect of nCRT was apparent on postoperative HRQOL compared with surgery alone. In addition to the improvement in survival, these findings support the view that nCRT according to the Chemoradiotherapy for Esophageal Cancer Followed by Surgery Study–regimen can be regarded as a standard of care

Ten-year outcome of neoadjuvant chemoradiotherapy plus surgery for esophageal cancer: the randomized controlled CROSS trial

PURPOSE Preoperative chemoradiotherapy according to the chemoradiotherapy for esophageal cancer followed by surgery study (CROSS) has become a standard of care for patients with locally advanced resectable esophageal or junctional cancer. We aimed to assess long-term outcome of this regimen. METHODS From 2004 through 2008, we randomly assigned 366 patients to either five weekly cycles of carboplatin and paclitaxel with concurrent radiotherapy (41.4 Gy in 23 fractions, 5 days per week) followed by surgery, or surgery alone. Follow-up data were collected through 2018. Cox regression analyses were performed to compare overall survival, cause-specific survival, and risks of locoregional and distant relapse. The effect of neoadjuvant chemoradiotherapy beyond 5 years of follow-up was tested with time-dependent Cox regression and landmark analyses. RESULTS The median follow-up was 147 months (interquartile range, 134-157). Patients receiving neoadjuvant chemoradiotherapy had better overall survival (hazard ratio [HR], 0.70; 95% CI, 0.55 to 0.89). The effect of neoadjuvant chemoradiotherapy on overall survival was not time-dependent (P value for interaction, P = .73), and landmark analyses suggested a stable effect on overall survival up to 10 years of follow-up. The absolute 10-year overall survival benefit was 13% (38% v 25%). Neoadjuvant chemoradiotherapy reduced risk of death from esophageal cancer (HR, 0.60; 95% CI, 0.46 to 0.80). Death from other causes was similar between study arms (HR, 1.17; 95% CI, 0.68 to 1.99). Although a clear effect on isolated locoregional (HR, 0.40; 95% CI, 0.21 to 0.72) and synchronous locoregional plus distant relapse (HR, 0.43; 95% CI, 0.26 to 0.72) persisted, isolated distant relapse was comparable (HR, 0.76; 95% CI, 0.52 to 1.13). CONCLUSION The overall survival benefit of patients with locally advanced resectable esophageal or junctional cancer who receive preoperative chemoradiotherapy according to CROSS persists for at least 10 years.Development and application of statistical models for medical scientific researchAnalysis and support of clinical decision makin

Effect of Neoadjuvant Chemoradiotherapy on Health-Related Quality of Life in Esophageal or Junctional Cancer: Results From the Randomized CROSS Trial

PurposeTo compare pre-agreed health-related quality of life (HRQOL) domains in patients with esophageal or junctional cancer who received neoadjuvant chemoradiotherapy (nCRT) followed by surgery or surgery alone. Secondary aims were to examine the effect of nCRT on HRQOL before surgery and the effect of surgery on HRQOL.Patients and MethodsPatients were randomly assigned to nCRT (carboplatin plus paclitaxel with concurrent 41.4-Gy radiotherapy) followed by surgery or surgery alone. HRQOL was measured using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire–Core 30 (QLQ-C30) and –Oesophageal Cancer Module (QLQ-OES24) questionnaires pretreatment and at 3, 6, 9, and 12 months postoperatively. The nCRT group also received preoperative questionnaires. Physical functioning (PF; QLQ-C30) and eating problems (EA; QLQ-OES24) were chosen as predefined primary end points. Predefined secondary end points were global QOL (GQOL; QLQ-C30), fatigue (FA; QLQ-C30), and emotional problems (EM; QLQ-OES24).ResultsA total of 363 patients were analyzed. No statistically significant differences in postoperative HRQOL were found between treatment groups. In the nCRT group, PF, EA, GQOL, FA, and EM scores deteriorated 1 week after nCRT (Cohen’s d: −0.93, P P P P P = .001, respectively). In both treatment groups, all end points declined 3 months postoperatively compared with baseline (Cohen’s d: −1.00, 0.33, −0.47, −0.34, and 0.33, respectively; all P P ConclusionAlthough HRQOL declined during nCRT, no effect of nCRT was apparent on postoperative HRQOL compared with surgery alone. In addition to the improvement in survival, these findings support the view that nCRT according to the Chemoradiotherapy for Esophageal Cancer Followed by Surgery Study–regimen can be regarded as a standard of care.FSW – Publicaties zonder aanstelling Universiteit Leide