We test the longstanding hypothesis, known as the dive constraint hypothesis, that the oxygenation demands of diving pose a constraint on aquatic mammal brain size.Using a sample of 23 cetacean species we examine the relationship among six different measures of relative brain size, body size, and maximum diving duration. Unlike previous tests we include body size as a covariate and perform independent contrast analyses to control for phylogeny. We show that diving does not limit brain size in cetaceans and therefore provide no support for the dive constraint hypothesis. Instead, body size is the main predictor of maximum diving duration in cetaceans. Furthermore, our findings show that it is important to conduct robust tests of evolutionary hypotheses by employing a variety of measures of the dependent variable, in this case, relative brain size.

Melanoma is a highly aggressive skin cancer with an increasing incidence. Melanoma in situ is an early, non-invasive form in which the tumor is confined to the epidermis. Treatment of melanoma in situ is challenging due to the frequent subclinical microscopic spread and to the presentation on the head and neck in cosmetically sensitive areas with chronic sun damage. Optimizing tumor eradication is imperative to reduce the potential progression into invasive disease and metastasis, all while maintaining cosmesis. Multiple treatment regimens have been implemented for managing difficult melanoma in situ tumors. We provide a thorough review of surgical, and non-surgical, management of melanoma in situ which can pose therapeutic dilemmas due to size, anatomic location, and subclinical spread.

Simulation offers an excellent model for the acquisition and assessment of dermatologic procedural skills. Cost and availability of instructors remain obstacles. Further studies are required to evaluate the implementation and effectiveness of these models.

No abstract

The authors have indicated no significant interest with commercial supporters.T he completely split earlobe is a common problem that is most often the result of sudden trauma or the downward progression of a partially split earlobe. Much of the literature addresses various repair techniques to optimize cosmetic outcomes and avoid pitfalls such as notching of the inferior margin due to scar contraction. Techniques range from a simple side-to-side closure to moreelaborate closures such as a Z-plasty (Casson's technique) and rotational flap (Effendi's technique). 1 Regardless of the repair method chosen, stabilization of the earlobe is critical for precise execution and an optimal outcome. In the following case, we employed 6-0 suture affixed to each inferior free margin of the split lobe to accomplish stabilization. This novel approach allowed us to impart tension in the exact amount and direction desired. It also gave us easier access to the anatomic site than manual manipulation or instrumentation such as a chalazion clamp or forceps.Side-to-side closure was chosen for repair of a leftsided, epithelialized, complete earlobe split on a middle-aged woman. Care was taken to match the anatomy of the right earlobe because this patient had a similar repair of that ear 1 year before. The design of the repair is essentially a triangle with the apex just superior to the defect. Fine adjustments were made by adjusting the width of the margins and by a slight offset of the triangle apex. After preparation of the field and anesthetization, a 6-0 Prolene suture was affixed to each inferior free margin of the defect. As a surgical assistant applied gentle tension, the margins were scored using a #15 blade (Figure 1), followed by excision using iris scissors (Figure 2). A single, deep, dissolvable suture was placed to approximate the wound edges, and complete closure was accomplished with vertical mattress sutures, ensuring exaggerated wound eversion and epidermal seal. No attempt was made to preserve the pierced canal. Figure 3 shows the repair 1 week later at suture removal.The literature is full of techniques for the repair of split earlobes. Stabilization of this floppy appendage is critical for any of these techniques but is only