A 77 yo patient with severe coronary artery disease presents for an emergency bowel resection. The patient weighs 73 kg. His initial hemoglobin is 12 and th ehematocrit is 35. We will allow him to lose ___________cc’s of blood. (Enter as a whole number)

What does elevation of the ST segment signify?

Which choice below represents the sequence of structures that a spinal needle will pass through in order to place local anesthetic properly?

Which two laryngeal nerves innervate the larynx?

Suppose a team of researchers studied if American adults aged 30-35 with post-traumatic stress disorder (PTSD) are at higher risk of alcohol use disorder. The researchers designed a prospective cohort study to study the association between PTSD and alcohol use disorder. In the first step the researcher included a random sample of American adults aged 30-35. Any individuals with alcohol use disorder at the start of the study were excluded from the study. In the second step, the researchers used medical records to determine if the participants had a diagnosis of PTSD. After five years of follow-up, the researchers interviewed the participants to determine if the participants had developed alcohol use disorder.   After hearing about this study, a fellow researcher is concerned that participants may not feel comfortable disclosing that they have alcohol use disorder. The fellow researcher warns their colleagues that this may bias the effect estimate from this study.   What source of bias is the fellow researcher concerned about?

Suppose a researcher conducted a cross-sectional study on attention deficit hyperactivity disorder (ADHD) and externalizing behaviors (e.g., rule-breaking or defiant behavior) among adolescents in Hillsborough County. During the summer months, the researcher works as a volunteer at a summer education program for adolescents who struggle with their schoolwork. Since the participants of the summer education program are adolescents, the researcher decides to invite the adolescents who attend the summer program for participation in the study.   The researcher is worried that there might be selection bias in the estimate of the effect of ADHD on externalizing behaviors because ADHD and externalizing behaviors are both reasons for participation in the summer program and are therefore also both affect study participation. To assess potential selection bias, the researcher drew the directed acyclic graph (DAG) in Figure 2.   Based on the DAG in Figure 2, will there be selection bias (yes/no)? (2 points) Explain your answer (max. 4 points).

What shape is Treponema pallidum?

Case 1 (Questions 11-13) Suppose a team of researchers conducts a case-control study on the association between hypertension and stroke among adults aged 50 and older in Florida. For this study, the researchers selected Floridian adults aged 50 and older who experienced a stroke as the cases. As controls, the researchers selected Floridian adults aged 50 or older who did not experience a stroke. To assess each participant’s exposure status, the researchers asked the participants to fill out a questionnaire in which the participants were asked to retrospectively report if they have had hypertension in the past. What source of measurement error could affect the measurement of hypertension in case 1? (2 points) Explain why you chose this source of measurement error (2 points).

Suppose a researcher was interested in investigating bone fractures as a potential exposure affecting pneumonia (i.e., lung infection). To study this, the researcher decided to sample individuals who attended the emergency room (ER) of Tampa General Hospital, because bone fractures and pneumonia are both reasons for attending the ER.    What form of selection bias may affect the results from this study?

Case 2 (Questions 19 and 20) Suppose a team of researchers conducted a prospective cohort study on the effect of physical activity on the 6-month risk of depression. To assess potential effect modification by gender, the researchers estimated the effect of physical activity on depression separately for men and women. In men, the estimated risk difference was -0.11 and the estimated risk ratio was 0.71. In women, the estimated risk difference was -0.07 and the estimated risk ratio was 0.80. Based on these effect estimates the researchers concluded that gender is indeed an effect modifier, so the researchers decided to report the conditional effect estimates in their manuscript.   Please provide an interpretation of the estimated risk ratio of 0.71. Assume that physical activity was the exposure level of interest and physical inactivity was the comparison level. (max. 4 points)