Operational Research: methods and applications

This is the final version. Available on open access from Taylor & Francis via the DOI in this recordThroughout its history, Operational Research has evolved to include methods, models and algorithms that have been applied to a wide range of contexts. This encyclopedic article consists of two main sections: methods and applications. The first summarises the up-to-date knowledge and provides an overview of the state-of-the-art methods and key developments in the various subdomains of the field. The second offers a wide-ranging list of areas where Operational Research has been applied. The article is meant to be read in a nonlinear fashion and used as a point of reference by a diverse pool of readers: academics, researchers, students, and practitioners. The entries within the methods and applications sections are presented in alphabetical order. The authors dedicate this paper to the 2023 Turkey/Syria earthquake victims. We sincerely hope that advances in OR will play a role towards minimising the pain and suffering caused by this and future catastrophes

FSH and LH responses to GnRH after ovariectomy in postmenopausal women

OBJECTIVE Whether the postmenopausal ovary is still playing a role in the control of gonadotrophin secretion in response to GnRH has not been investigated. The aim of the present study was to test this hypothesis by examining changes in basal and GnRH-induced gonadotrophin secretion in postmenopausal women after bilateral ovariectomy. DESIGN The responses of LH and FSH to GnRH [10 mug intravenously (i.v.)] were investigated in postmenopausal women from 2 days before to 8 days after total abdominal hysterectomy plus bilateral ovariectomy. PATIENTS Nine postmenopausal women aged 52-67 years and between 5 and 15 years after menopause. In all cases the ovaries were histologically normal. MEASUREMENTS Pituitary responses to GnRH were calculated every 12-24 h as the net increases in LH (DeltaLH) and FSH (DeltaFSH) at 30 min above the basal values. Basal values of oestradiol (E2) and testosterone were also measured. RESULTS Basal values of FSH showed a significant decrease on postoperative days 2 (P < 0.01) and 8 (P = 0.03) as compared to day 0, while at the same time points after the operation LH values were marginally lower than on day 2 (P = 0.05). Serum E2 values showed a gradual increase up to postoperative day 1 (P = 0.04) and a gradual decline thereafter. Basal testosterone concentrations decreased gradually and significantly after ovariectomy and were significantly lower on day 8 than on day 0 (P < 0.01). DeltaFSH and DeltaLH responses to GnRH did not change significantly with time. A temporary increase at 12 h after the operation was not significant. CONCLUSIONS These results demonstrate for the first time that the removal of the ovaries in postmenopausal women does not affect GnRH-induced gonadotrophin secretion in the short term. It is suggested that the postmenopausal ovary is not a dominant regulator of hypothalamic-pituitary interactions