The manual is suitable for training electrocardio- without digital recording and that are accompanied graphers and technicians and can be accompanied by other uniquely rich data. Despite my expectations by sets of training ECGs already coded by trainers. during the 1960s that such archives would cease to It is our expectation that the manual will serve as a be used after the introduction of digital recording, reference, guide, and training source for those con- the tide of such treasures has hardly ebbed. ducting studies that require objective evidence of The changes included in this edition arise from cardiac disease, both prevalent and incident, by non- more than a quarter of a century of directing central invasive, highly standardized, inexpensive record- ECG reading and research centers and collectively ing of the electrocardiogram. In our own ECG Read- 60+ large and small epidemiologic studies and m- ing Center, this has included epidemiologic studies ticenter national and international clinical trials. The among healthy populations, diabetics, psychiatric changes include the description of a new measuring patients, pregnant women, cohorts of patients with loupe in Chap. 3, developed over the past decade, to clinical heart disease, populations exposed to envi- better serve a more ef? cient and a more extensive ronmental contaminants such as arsenic, populations span for measurement of relevant durations, voltages, exposed to Chagas disease, and in clinical trials of and deviations from the isoelectric line. In Chap.

If you are a bird watcher, (and one of every seven of us is), you already have the knowledge, equipment, and the opportunity to also observe butterflies. You know different seasons and different habitats have different species. You must be in the right place at the right time to see the particular species you are hunting. You may take photographs or may just use binoculars, but you probably compile a "Life List" of the species you find. This book is intended to help you and the amateur butterflier to find and identify the various species of Minnesota butterflies. It also is a journal for you to write in your observations of species found, dates, locations, weather conditions, habitat types, or any other interesting observations (a "Life List" with detail). Many People are enjoying the new activity of butterfly gardening, This is great. I strongly encourage it. But please don't be deceived into thinking all butterflies will come. Many resident and migrant butterflies will be attracted to gardens, but some are so habitat specific they won't cross a road and thus cannot be attracted. To see these, you must go hunt for them. I try to identify these for you in this book and help you find them if you are willing to hunt for them.