The following synopsis is based on data from a study of the occurrence of HIV infection among prisoners in Nevada. A study published in the American Journal of Public Health investigated the occurrence of HIV infection among prisoners in Nevada. Of 1,105 prison inmates who were tested for HIV at the start of the study, 36 were found to be infected. All uninfected persons were followed for a total of 1,207 person-years and retested for HIV upon release from prison. Two of the uninfected inmates demonstrated evidence of new HIV infection contracted in prison.
1. Calculate the incidence rate of HIV acquisition among these prisoners.
2. How many individuals provided data for the calculation in Question 2?

Which of the following represents a difference between viruses and viroids? a) viruses infect many types of cells, whereas viroids infect only prokaryotic cells.b) viruses have capsids composed of protein, whereas viroids have no capsids.c) viruses have genomes composed of rna, whereas viroids have genomes composed of dna.d) viruses cannot pass through plasmodesmata, whereas viroids can.

A46-year-old man with a history of hypertension and hypercholesterolemia visits the physician for a routine followup. the patient's job involves a lot of travelling, and he admits to occasionally forgetting to take his medications with him when he travels. he complains of several episodes of chest pain in the past few months. the pain is sharp in nature, mainly over his lower chest and epigastrium, and tends to come on when walking. he believes these episodes are due to indigestion and has been taking antacids. there is a family history of heart disease, and his father died of a heart attack at age 48. on physical examination, his blood pressure is 150/80 mmhg and heart rate is 86/min. his lungs are clear to auscultation. cardiac auscultation reveals normal rate and rhythm, without rubs, gallops, or murmurs. there is no pedal oedema. he is sent for an exercise stress test. five minutes into the test, he develops st depression of 3mm in leads v1-v5. the st segment depression is greater than 0.12 seconds in duration and the stress test is stopped. which of the following is the most appropriate next step in management? - coronary angiography- holter monitor- no further tests are required- repeat stress test with thallium- upper gastrointestinal endoscopy

Lyme disease is caused by a bacterium transmitted to people by deer ticks. deer ticks are almost never born infected with the bacterium, but they can pick it up from feeding on an infected host in any of the tick's three successive stage of development: larva, nymph, adult. once infected, a tick remains infected through any subsequent developmental stages, but since a tick feeds on only one host in each stage, it follows that . people can be infected only by being bitten by a tick that is either in larval stage or in the nymph stage b. people cannot be infected by a tick that picked up the lyme disease bacterium in the adult stage c. it is not possible for a person to be infected by a tick that is in the nymph stage or by a tick that was infected with the bacterium while in the nymph stage d. people infected with the lyme disease bacterium cannot transmit bacterium to adult deer ticks e. only deer ticks that are adults can transmit the lyme disease bacterium to people