The Billings Method

Doctor Billings, who researched and formulated the ovulation method, explains its use.

Wanting a baby? Not wanting a baby just now? Nature has provided every woman with a precise signal of her state of fertility, which she can quickly learn to recognise. This simple fact is the basis of the Billings Method, which has helped millions of woman around the world to tune into their own bodies and achieve healthy, natural fertility control. Using the Billings Method you and your partner can be confident of knowing every day whether you are fertile or infertile, and so decide when to make love, depending on wether you want to achieve or avoid pregnancy. This book is a clear guide for all women, whether your cycles are regular or irregular, whether you are coming off the Pill, breastfeeding a new baby, or approaching the menopause. 'This is knowledge of her body that every woman ought to have' DR EVELYN BILLINGS

Nonlinear System Identification: NARMAX Methods in the Time, Frequency, and Spatio-Temporal Domains describes a comprehensive framework for the identification and analysis of nonlinear dynamic systems in the time, frequency, and spatio-temporal domains. This book is written with an emphasis on making the algorithms accessible so that they can be applied and used in practice. Includes coverage of: The NARMAX (nonlinear autoregressive moving average with exogenous inputs) model The orthogonal least squares algorithm that allows models to be built term by term where the error reduction ratio reveals the percentage contribution of each model term Statistical and qualitative model validation methods that can be applied to any model class Generalised frequency response functions which provide significant insight into nonlinear behaviours A completely new class of filters that can move, split, spread, and focus energy The response spectrum map and the study of sub harmonic and severely nonlinear systems Algorithms that can track rapid time variation in both linear and nonlinear systems The important class of spatio-temporal systems that evolve over both space and time Many case study examples from modelling space weather, through identification of a model of the visual processing system of fruit flies, to tracking causality in EEG data are all included to demonstrate how easily the methods can be applied in practice and to show the insight that the algorithms reveal even for complex systems NARMAX algorithms provide a fundamentally different approach to nonlinear system identification and signal processing for nonlinear systems. NARMAX methods provide models that are transparent, which can easily be analysed, and which can be used to solve real problems. This book is intended for graduates, postgraduates and researchers in the sciences and engineering, and also for users from other fields who have collected data and who wish to identify models to help to understand the dynamics of their systems.

The "contraceptive revolution" of the 1960s and 1970s introduced totally new contraceptive options and launched an era of research and product development. Yet by the late 1980s, conditions had changed and improvements in contraceptive products, while very important in relation to improved oral contraceptives, IUDs, implants, and injectables, had become primarily incremental. Is it time for a second contraceptive revolution and how might it happen? Contraceptive Research and Development explores the frontiers of science where the contraceptives of the future are likely to be found and lays out criteria for deciding where to make the next R&D investments. The book comprehensively examines today's contraceptive needs, identifies "niches" in those needs that seem most readily translatable into market terms, and scrutinizes issues that shape the market: method side effects and contraceptive failure, the challenge of HIV/AIDS and other sexually transmitted diseases, and the implications of the "women's agenda." Contraceptive Research and Development analyzes the response of the pharmaceutical industry to current dynamics in regulation, liability, public opinion, and the economics of the health sector and offers an integrated set of recommendations for public- and private-sector action to meet a whole new generation of demand.

I opened my series editor manuscript of The Handbook of Contraception: A Guide for Practical Management, edited by Drs. Donna Shoupe and Siri Kjos, on a tiny plane on the way to giving a lecture in Albany, NY. I expected to peruse the ma- script, and found that I could not put it down. The Handbook of Contraception: A Guide for Practical Management is an incredibly informative and enjoyable read. In keeping with the objective of this series for primary care clinicians, there is a quality in this title that is uncommon among medical textbooks. The chapters of this book are written with extraordinary intelligence and und- standing, and with attention to practical considerations in the selection and mana- ment of contraceptive options. The authors have reviewed the science behind contraception, including the chemical structure and effects of hormonal contraception, physiology of contraception, efficacy rates, and side effects, as well as the practical considerations that are relevant in helping patients choose between different cont- ceptive options. They do this with a clarity of language and intent that lets the book cover with sufficient detail the full range of questions that any primary care clinician will have regarding any of the traditional or new contraceptive options. Also included in each chapter is a section on “counseling tips,” which explicitly answers many of the questions that clinicians and their patients often have when discussing contraceptive options. For a book so useful and well done, the editors and authors deserve our thanks.

Using Science to Improve the BLM Wild Horse and Burro Program: A Way Forward reviews the science that underpins the Bureau of Land Management's oversight of free-ranging horses and burros on federal public lands in the western United States, concluding that constructive changes could be implemented. The Wild Horse and Burro Program has not used scientifically rigorous methods to estimate the population sizes of horses and burros, to model the effects of management actions on the animals, or to assess the availability and use of forage on rangelands. Evidence suggests that horse populations are growing by 15 to 20 percent each year, a level that is unsustainable for maintaining healthy horse populations as well as healthy ecosystems. Promising fertility-control methods are available to help limit this population growth, however. In addition, science-based methods exist for improving population estimates, predicting the effects of management practices in order to maintain genetically diverse, healthy populations, and estimating the productivity of rangelands. Greater transparency in how science-based methods are used to inform management decisions may help increase public confidence in the Wild Horse and Burro Program.