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It remains unclear which individuals with subthreshold depression benefit most from psychological intervention, and what long-term effects this has on symptom deterioration, response and remission.
Aims
To synthesise psychological intervention benefits in adults with subthreshold depression up to 2 years, and explore participant-level effect-modifiers.
Method
Randomised trials comparing psychological intervention with inactive control were identified via systematic search. Authors were contacted to obtain individual participant data (IPD), analysed using Bayesian one-stage meta-analysis. Treatment–covariate interactions were added to examine moderators. Hierarchical-additive models were used to explore treatment benefits conditional on baseline Patient Health Questionnaire 9 (PHQ-9) values.
Results
IPD of 10 671 individuals (50 studies) could be included. We found significant effects on depressive symptom severity up to 12 months (standardised mean-difference [s.m.d.] = −0.48 to −0.27). Effects could not be ascertained up to 24 months (s.m.d. = −0.18). Similar findings emerged for 50% symptom reduction (relative risk = 1.27–2.79), reliable improvement (relative risk = 1.38–3.17), deterioration (relative risk = 0.67–0.54) and close-to-symptom-free status (relative risk = 1.41–2.80). Among participant-level moderators, only initial depression and anxiety severity were highly credible (P > 0.99). Predicted treatment benefits decreased with lower symptom severity but remained minimally important even for very mild symptoms (s.m.d. = −0.33 for PHQ-9 = 5).
Conclusions
Psychological intervention reduces the symptom burden in individuals with subthreshold depression up to 1 year, and protects against symptom deterioration. Benefits up to 2 years are less certain. We find strong support for intervention in subthreshold depression, particularly with PHQ-9 scores ≥ 10. For very mild symptoms, scalable treatments could be an attractive option.
Contest Problem Book VI chronicles the high school competitions sponsored by the Mathematical Association of America. It contains 180 challenging problems from the six years of the American High School Mathematics Examination [AHSME], 1989 through 1994, as well as a selection of other problems. Many problem solving techniques for problems in this book show alternative approaches that appear in print for the first time. Some aspects of mathematical problem solving unique to competitions is discussed. Useful tools are selected from important areas of high school mathematics. A Problems Index classified the 180 problems in the book into subject areas: Algebra (with 65 subclasses), Complex Numbers (with 11 subclasses), Discrete Mathematics (with 20 subclasses), Geometry (with 43 subclasses), Number Theory (with 24 subclasses), Statistics (with 5 subclasses), and Trigonometry (with 12 subclasses). Many subclasses have sub-subclasses, some with over a dozen. The Pigeon Hole Principle proves that some problems must appear in more than one class. That, in fact, is the case! Outstanding problems combine elementary techniques from diverse areas of mathematics, occasionally three or more. You will find many of them here.
Patients with cyanotic congenital cardiac disease often develop major aortopulmonary collaterals. Vascular endothelial growth factor is a key promoter of angiogenesis. Its soluble receptor-1 acts as a potent antagonist. We studied 30 infants with cyanotic congenital cardiac disease and 27 infants with acyanotic congenital cardiac disease. Central venous plasma vascular endothelial growth factor and soluble vascular endothelial growth factor receptor-1 levels were measured before, and 24 and 96 hours after surgery. There was no difference between plasma vascular endothelial growth factor levels in infants with cyanotic and those with acyanotic congenital cardiac disease. In cyanotic infants, the soluble vascular endothelial growth factor receptor-1 levels tended to be higher than in the acyanotic infants. In conclusion, there is no significant difference in the plasma levels of vascular endothelial growth factor and its soluble receptor-1 between infants with cyanotic and those with acyanotic congenital cardiac disease.
The annual American Mathematics Competitions are a program of the Mathematical Association of America for pre-college students. Great care is taken to create new and interesting problems for these competitions. After each examination, all the problems and their solutions are made public in individual pamphlets so students can learn mathematics by practicing for future contests, and to give teachers new and exciting problems for their classes.
The oldest of the American Mathematics Competitions is the American High School Mathematics Examination [AHSME], first given in 1949. This book presents the problems and solutions from the 40th through 45th annual AHSMEs, the examinations administered 1989 through 1994. All the statements of the problems appear in this book exactly as they appeared on the examinations.
The solutions in this book include all the official solutions originally made available after the competitions, many enhanced. In addition, this book includes many alternative solutions that have never been published before.
How To Use This Book
Students who will participate in the American Mathematics Competitions and many other mathematics contests can use the problems in this book for practice. The rules for the AHSME appear on the page xix, preceding the statements of the AHSME problems so students can try the examinations under simulated contest conditions. Answers follow the questions from each competition, together with the percentage of times honor roll students used each answer choice. A few comments calling attention to unusually attractive ‘distractors’ are also included. One or more complete solutions to each problem are given in the section following all the examination questions and answers.
The study of mathematics is the same, whether it be for a mathematics class, for one's pure enjoyment in gaining new insights, or for competitions. The use of certain mathematical tools may be encountered more frequently in mathematics competition problems than in text book problems. However, responsible organizers of mathematics competitions try to align the topics they emphasize reasonably well with current curricula. For example, statistics was becoming a more important topic in the secondary schools during the years of the competitions in this book. Note the development from problems 24 on the 41st AHSME and 16 on the 42nd AHSME which are about weighted averages, problems that are actually more algebraic than statistical, to problem 24 on the 45th AHSME which presumes knowledge of fundamental statistical terms.
Tools for Mathematics Competitions
The tools for doing well on the AHSME and AIME are all the topics in a pre-calculus curriculum including some elementary probability, statistics, discrete mathematics, and number theory. The creative aspect of problem solving on competitions lies in the skill of knowing which of these tools to select for which problems. Facility with the use of these tools and their selection can be gained by entering mathematics competitions and by practicing on contests such as those in this book.
Good competitors on timed tests practice to the point where they recognize the use of certain sequences of these tools. They can write down the results without any intermediate writing, almost as if they have the result memorized. One very simple example might be the formula for the area of an equilateral triangle of side s.