Evaluation of the testosterone response to hCG and the identification of a presumed anorchid dog

A two-year-old dog was presented with no scrotal testes. There was no history of castration but at laparotomy no testes were found. To confirm that the dog was truly anorchid a human chorionic gonadotrophin stimulation test was performed. This was then validated in normal entire and castrated dogs.     

Chronology of hawaiian glaciations

Both potassium/argon and carbon-14 ages of lava flows and tephra layers interstratified with glacial deposits on Mauna Kea, Hawaii, indicate that four episodes of ice cap glaciation culminated about 20,000, 55,000, 135,000, and 250,000 years ago. These episodes are correlated with marine isotope stages 2, 4, 6, and 8, marking times of high global ice volume.     

Evidence for substantial variations of atmospheric hydroxyl radicals in the past two decades

The hydroxyl radical (OH) is the dominant oxidizing chemical in the atmosphere. It destroys most air pollutants and many gases involved in ozone depletion and the greenhouse effect. Global measurements of 1,1,1-trichloroethane (CH3CCl3, methyl chloroform) provide an accurate method for determining the global and hemispheric behavior of OH. Measurements show that CH3CCl3 levels rose steadily from 1978 to reach a maximum in 1992 and then decreased rapidly to levels in 2000 that were lower than the levels when measurements began in 1978. Analysis of these observations shows that global OH levels were growing between 1978 and 1988, but the growth rate was decreasing at a rate of 0.23 +/- 0.18% year(-2), so that OH levels began declining after 1988. Overall, the global average OH trend between 1978 and 2000 was -0.64 +/- 0.60% year(-1). These variations imply important and unexpected gaps in current understanding of the capability of the atmosphere to cleanse itself.     

Plasticity of motor behavior in monkeys with crossed forelimb nerves

Monkeys in which nerves innervating the flexor muscles of the forearm and hand (the ulnar or the median nerve) had been surgically cross-united with the nerve innervating the extensor muscles (the radial nerve), and vice versa, showed excellent (ulnar-radial crosses) to moderate (median-radial crosses) control of movement performance after regeneration. Antagonistic movement responses were seen occasionally, but these were corrected almost immediately. Stimulation of the crossed nerves showed that they had innervated the antagonistic muscle groups. The results reveal the capacity of the primate central nervous system to adapt to gross disturbances imposed on the execution of movements by changes in peripheral innervation.     

Muscle relaxation: evidence for an intrafibrillar restoring force in vertebrate striated muscle

Observations of contracting muscle fibrils in cultured cells indicate that the force which restores the resting length of the sarcomere comes from the contractile elements themselves and not from external elasticity, as is now generally accepted. In light of biochemical studies on the contraction-relaxation cycle, it is postulated that the elongating force is one of internal elasticity in the sarcomere, which arises during contraction from the distortion of bonds between filaments and/or structural proteins. This mechanism of restoration may serve to establish optimal sarcomere length for production of maximum contractile force, and in cardiac muscle this mechanism may be a factor in ventricular filling.     

Air containing nitrogen-15 ammonia: foliar absorption by corn seedlings

Thirty-day-old corn seedlings, grown in the greenhouse with different concentrations of supplemental nitrate nitrogen, were moved to a constant-temperature growth chamber and sealed in a 560-liter tent made of polyvinyl chloride. The plants were exposed to air containing ammonia labeled with nitrogen-15 (1, 10, and 20 parts per million) for 24 hours and then harvested. The nitrogen-15 content of the tops and roots showed that at 1 part per million 43 percent of the ammonia was absorbed, whereas at 10 and 20 parts per million, 30 percent of the ammonia was absorbed. The results demonstrate that growing plants may be a natural sink for atmospheric ammonia.