Organ equivalent doses of patients undergoing chest computed tomography: measurements with TL dosimeters in an anthropomorphic phantom.

Dose reduction in patients undergoing computed tomography (CT) examinations has become a concern in many countries. CT dosimetric quantities were defined aiming optimization of CT procedures, organ absorbed doses and effective doses have been calculated for radiation risk assessments in patients. In this work, an experimental methodology was established for measuring organ doses with thermoluminescent (TL) dosimeters in an anthropomorphic phantom for routine CT chest examinations. Results may be useful for validating computational software used for CT dose calculations.

Photophase influence on the reproductive diapause, seasonal morphs, and feeding activity of Euschistus heros (Fabr., 1798) (Hemiptera: Pentatomidae).

Laboratory studies were conducted to verify the influence of photophase on diapause incidence in the Neotropical brown stink bug, Euschistus heros (Fabr., 1798), fed with soybean [Glycine max (L.)] Merrill pods. Nymphs were maintained at three different photophases: 10 h, 12 h, and 14 h, with constant temperature of 25 +/- 1 degree C and relative humidity of 65 +/- 5%. With 14 h, approximately 100% of the adults showed mature reproductive organs; the shoulder (spine) length was significantly greater (2.96 and 2.79 mm for females and males, respectively) than those of bugs maintained at the photophase of 12 h (2.60 mm for females and males) and 10 h (2.59 and 2.53 mm for females and males). At the longer photophase (14 h), E. heros showed better reproductive performance and greater feeding activity than insects reared at 10 h and 12 h; in all photophases bugs tended to reduce feeding from the 1st to the 6th week of life. Body color was considered an unreliable parameter to indicate diapause incidence. However, at 14 h, 60% of the insects were dark brown and 40% were reddish brown. These results indicate that E. heros enters reproductive diapause with photophase of 12 hours or less, showing immature reproductive organs or with intermediate development, with shoulder (spine) less developed and reduced feeding activity.

Photophase influence on the reproductive diapause, seasonal morphs, and feeding activity of Euschistus heros (Fabr., 1798) (Hemiptera: Pentatomidae)

Laboratory studies were conducted to verify the influence of photophase on diapause incidence in the Neotropical brown stink bug, Euschistus heros (Fabr., 1798), fed with soybean [Glycine max (L.)] Merrill pods. Nymphs were maintained at three different photophases: 10 h, 12 h, and 14 h, with constant temperature of 25 ± 1øC and relative humidity of 65 ± 5 percent. With 14 h, aproximately 100 percent of the adults showed mature reproductive organs; the shoulder (spine) length was significantly greater (2.96 and 2.79 mm for females and males, respectively) than those of bugs maintained at the photophase of 12 h (2.60 mm for females and males) and 10 h (2.59 and 2.53 mm for females and males). At the longer photophase (14 h), E. heros showed better reproductive performance and greater feeding activity than insects reared at 10 h and 12 h; in all photophases bugs tended to reduce feeding from the 1st to the 6th week of life. Body color was considered an unreliable parameter to indicate diapause incidence. However, at 14 h, 60 percent of the insects were dark brown and 40 percent were reddish brown. These results indicate that E. heros enters reproductive diapause with photophase of 12 hours or less, showing immature reproductive organs or with intermediate development, with shoulder (spine) less developed and reduced feeding activity