RESUMO
The thoracic cavity contains vital cardiovascular and pulmonary structures. Few congenital anatomical variations in the bronchial tree and pulmonary vasculature have been reported. Understanding such variants is crucial during surgical procedures that involve the thorax. During routine dissection of an 89-year-old male cadaver as part of a first-year anatomy course, an anomaly of the bronchial tree was discovered. The left lung hilum was notable for the pulmonary artery being posterior to the mainstem bronchus. The case report describes normal lung development and anatomy and the significance of this novel variation in which has not been previously described in the literature.
RESUMO
Isolating the relative effects of episodic disturbances and chronic stressors on long-term community change is challenging. We assessed the impact of an episodic disturbance associated with human visitation (boat anchoring) relative to other drivers of long-term change on coral reefs. A one-time anchoring event at Crab Cove, British Virgin Islands, in 2004 caused rapid losses of coral and reef structural complexity that were equal to the cumulative decline over 23 years observed at an adjacent site. The abundance of small site-attached reef fishes dropped by approximately one quarter after the anchoring event, but this drop was not immediate and only fully apparent two years after the anchoring event. There was no obvious recovery from the impact, and no evidence that this episodic impact accelerated or retarded subsequent declines from other causes. This apparent lack of synergism between the effect of this episodic human impact and other chronic stressors is consistent with the few other long-term studies of episodic impacts, and suggests that action to mitigate anchor damage should yield predictable benefits.
