Drake equation
Drake equation A formula for calculating the number of civilizations in our Galaxy from which we might detect artificial transmissions. The equation, proposed in 1961 by the American radio astronomer Frank Donald Drake (1930– ), multiplies together the following factors:
R*, the rate of formation of stars in our Galaxy with suitable environments for the development of intelligent life;
fp, the fraction of those stars that have planetary systems; n
e, the number of planets in each system that are suitable for life;
fl, the fraction of such planets on which life actually arises;
fi, the fraction of life‐bearing planets on which intelligent life emerges;
fc, the fraction of civilizations that release detectable signs of their existence into space; and
L, the average lifetime of such civilizations. The solution to the equation depends on the values assigned to each factor, many of which are not well determined. Possible results for the number of communicative civilizations in the Galaxy at present range from almost zero to many thousands.
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Pregnancy part eight: Medical complications
Magazine article from: Community Practitioner; 11/1/2003; ; 700+ words
; ...medical problem in pregnancy and complicates up to 4 per cent of pregnancies.1-2 The course...frequently altered by pregnancy, but the mechanisms...throughout their pregnancies. They should...care throughout pregnancy and childbirth...
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Pregnancy-related mortality - Georgia, 1990-1992.
Newspaper article from: Morbidity and Mortality Weekly Report; 2/10/1995; 700+ words
; Many pregnancy-related deaths are preventable. State...prevention strategies. Surveillance for pregnancy-related deaths based only on ascertainment...assessed the completeness of reporting of pregnancy-related deaths during 1990-1992 by...
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Heterotopic pregnancy presenting as an acute abdomen: A diagnostic masquerader
Magazine article from: The American Surgeon; 3/1/2000; ; 700+ words
; ...along with a normal uterine pregnancy. A right salpingectomy was...continuing with a normal pregnancy. Discussion Simultaneous ectopic and uterine pregnancies are rare. The presence of such an ectopic pregnancy is also called heterotopic...
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Pregnancy testing and counseling: a university health center's 5-year experience. (contraceptive use)
Magazine article from: Journal of American College Health; 3/1/1998; ; 700+ words
; ...pregnancy Unintended pregnancy has become a common...result of unplanned pregnancies.[1] In addition...and rates of previous pregnancy. We also examined...the outcome of their pregnancies. METHOD Our sample...women presenting for pregnancy tests at the student...
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Pregnancy intentions among Salvadoran fathers: results from the 2003 National Male Reproductive Health Survey.
Magazine article from: International Family Planning Perspectives; 12/1/2005; ; 700+ words
; ...commonly say that pregnancies are unintended...However, men's pregnancy intentions are...For 20% of all pregnancies, men perceived that their partner's pregnancy intentions differed...opportunity to compare pregnancy intentions between...Two types of pregnancies are conventionally...
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Pregnancy complications are a stress test for future maternal health and pregnancies.
Newspaper article from: NewsRx Health & Science; 8/9/2009; 700+ words
; Predicting whether pregnancy complications affect long-term maternal health as well as future pregnancies is at the heart of two studies conducted...higher risk of hypertension after pregnancy. Working in collaboration with the...
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Pregnancy Acceptance, Parenting Stress, and Toddler Attachment in Low-Income Black Families
Magazine article from: Journal of Marriage and Family; 2/1/2007; ; 700+ words
; ...report that pregnancy was desired...unintended pregnancies are unhappy...whether the pregnancy was accidental...unintended pregnancies are further...unplanned pregnancies. We did not ask about pregnancy timing because...
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Pregnancy Complications are a Stress Test for Future Maternal Health and Pregnancies.
M2 Presswire; 7/8/2009; 700+ words
; ...Yale University: Pregnancy Complications are...Maternal Health and Pregnancies(C)1994-2009...Predicting whether pregnancy complications affect...well as future pregnancies is at the heart...who have had two pregnancies complicated by...hypertension after pregnancy. Working in ...
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Pregnancy rate for teens reached record low in 1997.(Nation)
Newspaper article from: The Washington Times; 6/13/2001; ; 700+ words
; ...year. * Total number of teen pregnancies: 872,000 * Teen pregnancy rate: 94.3 pregnancies per 1,000 teens ages 15 to 19 * Peak teen-pregnancy rate: 116.5 pregnancies per 1,000 teens (1991) * Total...
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Pregnancies swamp Navy sea operations: Female sailors forget to take pill.(A)
Newspaper article from: The Washington Times; 2/13/1997; ; 700+ words
; ...rate of unwanted pregnancies. Also urged are...toward prevention of pregnancy while on sea duty...sign that their pregnancies were unintentional...Behavioral Correlates of Pregnancy Aboard Navy Ships...the effects unwed pregnancies can have on their...has stated that pregnancy and a ...
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Pregnancy, Complications of
Encyclopedia entry from: Complete Human Diseases and Conditions
...especially due to pregnancy or obesity. * varicose...and even between pregnancies for an individual woman...Common Complications of Pregnancy? Most women get through...unexpected end of a pregnancy is called stillbirth...many as 40 percent of pregnancies end in miscarriage...
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pregnancy
Book article from: The Oxford Companion to the Body
pregnancy The biological event of pregnancy is established when a fertilized egg successfully implants...bloodstream to the ovary prevents its own rejection. Early pregnancy continues to be maintained by the hormones produced by the...
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Pregnancy
Book article from: Nutrition and Well-Being A to Z
...weight gain during pregnancy are based on the Institute...vary greatly in normal pregnancies with normal birth outcomes...trimester weight gain on pregnancy outcome is unclear...2 In adolescent pregnancies, there are no established...obesity in adolescents. Pregnancy Nutrition ...
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Ectopic Pregnancy
Encyclopedia entry from: Gale Encyclopedia of Medicine, 3rd ed.
...women with ectopic pregnancies have a history of pelvic...the risk of ectopic pregnancy. They include: Endometriosis...preventing ectopic pregnancies. Therefore, if a...about 15% have ectopic pregnancies. Surgery on a fallopian...The risk of ectopic pregnancy can be as high as 60...
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Pregnancy and Cancer
Encyclopedia entry from: Gale Encyclopedia of Cancer
...Women who desire future pregnancies should discuss this...other evidence of a pregnancy. Before undergoing...cancer and trimester of pregnancy will determine if immediate...out of every 3, 000 pregnancies. As in the non-pregnant...negative). The pregnancy hormones accelerate...
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