The physical demands for swimming and feeding change dramatically over the course of development for many aquatic animals. Indeed, in teleosts, the transition from larva to adult involves major shifts in both trophic morphology and feeding behavior. A spike in thyroid hormone (TH) coordinates many developmental processes that occur during this adult transition in numerous vertebrate species. Using mutant and transgenic zebrafish, we tested the hypothesis that TH is essential for the transition from larval to adult feeding kinematic profiles. We found that every measured kinematic variable that distinguished larvae from adults also differentiated hypothyroid from wild-type (WT) euthyroid adults, suggesting that TH is indeed necessary for the onset of mature feeding behaviors. In contrast, feeding kinematics in hyperthyroid adults were extremely similar to those measured in euthyroid adults. Altered TH signaling underlies pedomorphosis in some amphibian species, and Danionella is a pedomorphic danionin genus. We therefore tested whether feeding kinematics of adult Danionella would more closely match larval zebrafish (and hypothyroid adults) than WT adult zebrafish. We found Danionella feeding kinematics resemble those of larval (and hypothyroid) zebrafish in multiple respects. Overall, we conclude that TH is essential in stimulating the onset of adult feeding kinematics in zebrafish, and that some of the underlying developmental pathways may have been lost in Danionella.

The ability to walk up to any computer, personalize it, and use it as one's own has long been a goal of mobile computing research. We present SoulPad, a new approach based on carrying an auto-configuring operating system along with a suspended virtual machine on a small portable device. With this approach, the computer boots from the device and resumes the virtual machine, thus giving the user access to his personal environment, including previously running computations. SoulPad has minimal infrastructure requirements and is therefore applicable to a wide range of conditions, particularly in developing countries. We report our experience implementing SoulPad and using it on a variety of hardware configurations. We address challenges common to systems similar to SoulPad, and show that the SoulPad model has significant potential as a mobility solution.

Protrusile jaws are a highly useful innovation that has been linked to extensive diversification in fish feeding ecology. Jaw protrusion can enhance the performance of multiple functions, such as suction production and capturing elusive prey. Identifying the developmental factors that alter protrusion ability will improve our understanding of fish diversification. In the zebrafish protrusion arises postmetamorphosis. Fish metamorphosis typically includes significant changes in trophic morphology, accompanies a shift in feeding niche and coincides with increased thyroid hormone production. We tested whether thyroid hormone affects the development of zebrafish feeding mechanics. We found that it affected all developmental stages examined, but that effects were most pronounced after metamorphosis. Thyroid hormone levels affected the development of jaw morphology, feeding mechanics, shape variation, and cranial ossification. Adult zebrafish utilize protrusile jaws, but an absence of thyroid hormone impaired development of the premaxillary bone, which is critical to jaw protrusion. Premaxillae from early juvenile zebrafish and hypothyroid adult zebrafish resemble those from adults in the genera Danionella, Devario, and Microdevario that show little to no jaw protrusion. Our findings suggest that evolutionary changes in how the developing skulls of danionin minnows respond to thyroid hormone may have promoted diversification into different feeding niches.

We propose a networking model that treats a user's set of personal devices as a MObile grouPEd Device, a MOPED, which appears as a single entity to the rest of the Internet . All communication for a user is directed to this point of presence . As the user moves through different environments, the devices cooperate to provide the user with access to all available communication resources . We present the basic networking functionality necessary to enable th e operation of MOPEDs and their integration into the Internet . We introduce a middleware layer to extend IP routing to work wit h MOPEDs and a lightweight IP encapsulation protocol, Multipat h Routing enCAPsulation (MRCAP), used to implement that middleware. . INTRODUCTIO NTrends in mobile communications have resulted in two significan t developments . First, advances in processor technology, both in increased processing power and decreased energy consumption, hav e led to the creation of a new breed of small intelligent devices , including palmtops, PDAs, smart phones, and other wearable devices . Many, if not all, of these devices have some form of wireless communication. As users collect multiple small computing devices, the amount of communication resources available to the user increases, as does the demand for coordination of these resources . Second, increasing demand for wireless connectivity has produce d rapid deployment of many new wireless technologies, with overlapping coverage in some areas . Considering the set of device s supporting a user, at any point in time, some subset of these devices may have connectivity . The convergence of these two developments presents a new challenge to provide coordination of a user's devices to provide better connectivity, and potentially more communication resources, to the user .The efficiency of a user's personal devices is limited by their isolation from each other . When the resources of a device are completely consumed (e .g ., a dead mobile phone battery), the user i s cut off from key services . Similarly, if a user leaves the coverage area of a device, the services accessed via that device becom e unreachable . As a user moves through different envi r onments, th e cooperation of devices brings the potential for increased bandwidt h and better connectivity by exposing to all devices the aggregatio n of services available to each individual device . Current technology and communication support provide connectivity between devices , but do not enable cooperation . The goal of our research is to bridg e this gap from communication to cooperation .Our model for mobile communication is based on two basic assumptions . First, a user should be able to create a representative presence on the Internet. All communication to a user is directe d through this presence. A user may even create multiple presence s (e .g ., business, personal) . If the presence has a unique network name, a single IP address, the user is in essence built into the network infrastructure . All communication destined for that presenc e is add...

Perspective 276 Investigating the evolution and development of biological complexity under the framework of epigenetics Kevin K. Duclos, Jesse L. Hendrikse, and Heather A. Jamniczky 263 Postmetamorphic ontogenetic allometry and the evolution of skull shape in Nest-building frogs Leptodactylus (Anura: Leptodactylidae) Ana S . Duport-Bru , María L . Ponssa , and Florencia Vera Candioti 247 Tooth and consequences: Heterodonty and dental replacement in piranhas and pacus (Serrasalmidae)