Genetic Diversity and Potential Function of Microbial Symbionts Associated with Newly Discovered Species of Osedax Polychaete Worms

We investigated the genetic diversity of symbiotic bacteria associated with two newly discovered species of Osedax from Monterey Canyon, CA, at 1,017-m (Osedax Monterey Bay sp. 3 "rosy" [Osedax sp. MB3]) and 381-m (Osedax Monterey Bay sp. 4 "yellow collar") depths. Quantitative PCR and clone libraries of 16S rRNA gene sequences identified differences in the compositions and abundances of bacterial phylotypes associated with the newly discovered host species and permitted comparisons between adult Osedax frankpressi and juveniles that had recently colonized whalebones implanted at 2,891 m. The newly discovered Osedax species hosted Oceanospirillales symbionts that are related to Gammaproteobacteria associated with the previously described O. frankpressi and Osedax rubiplumus (S. K. Goffredi, V. J. Orphan, G. W. Rouse, L. Jahnke, T. Embaye, K. Turk, R. Lee, and R. C. Vrijenhoek, Environ. Microbiol. 7:1369-1378, 2005). In addition, Osedax sp. MB3 hosts a diverse and abundant population of additional bacteria dominated by Epsilonproteobacteria. Ultrastructural analysis of symbiont-bearing root tissues verified the enhanced microbial diversity of Osedax sp. MB3. Root tissues from the newly described host species and O. frankpressi all exhibited collagenolytic enzyme activity, which covaried positively with the abundance of symbiont DNA and negatively with mean adult size of the host species. Members of this unusual genus of bone-eating worms may form variable associations with symbiotic bacteria that allow for the observed differences in colonization and success in whale fall environments throughout the world's oceans

Black Underrepresentation in Science and Technology

The United States is experiencing a crisis in the training of scientific and technical personnel. A recent report from the National Science Foundation (NSF) indicates that the number of U.S. citizens earning science and engineering doctorates has decreased nearly 5% since 1980. The National Research Council\u27s study of the adequacy of research support for the mathematical sciences in the United States reveals that not only has the production of Ph.D.s in mathematics declined since 1969-70, but the percentage of U.S. citizens receiving those degrees fell during the last decade from 78% of all mathematics Ph.D.s to only 61% of all mathematics Ph.D.s. Heller reports that there has been a 15% decline between 1977 and 1984 in the number of Americans studying for graduate degrees in mathematics. Despite these shortages, people of color and white women remain severely underrepresented in scientific and technical professions; this has been the case historically and continues to be true today. In recent years the relative underrepresentation of minority group members and women in the various sectors of American life has received national attention and, to some extent, national action. While a number of initiatives have been undertaken to address this problem, it still remains a serious one, particularly for blacks, Hispanics, and American Indians. Students from these groups continue to underachieve in mathematics, science, and technical subjects. Furthermore, youths from these groups are less likely to take higher level high school mathematics and science courses or to major in mathematics, science, and technical fields in college. The net effect of these circumstances is that members of these groups are underrepresented at the professional levels and their communities are underserved or ill-served by these fields. Perhaps what is most distressing is that these trends suggest that this situation will continue for some time into the future

Taxation of Income in Respect of a Decedent

Taxation of Income in Respect of a Deceden

Taxation of Income in Respect of a Decedent

Taxation of Income in Respect of a Deceden

Five Facts about Value-Added Exports and Implications for Macroeconomics and Trade Research

Due to the rise of global supply chains, gross exports do not accurately measure the amount of value added exchanged between countries. I highlight five facts about differences between gross and value-added exports. These differences are large and growing over time, currently around 25 percent, and manufacturing trade looks more important, relative to services, in gross than value-added terms. These differences are also heterogenous across countries and bilateral partners, and changing unevenly across countries and partners over time. Taking these differences into account enables researchers to obtain better quantitative answers to important macroeconomic and trade questions. I discuss how the facts inform analysis of the transmission of shocks across countries; the mechanics of trade balance adjustments; the impact of frictions on trade; the role of endowments and comparative advantage; and trade policy

Early and late complications of bariatric operation.

Weight loss surgery is one of the fastest growing segments of the surgical discipline. As with all medical procedures, postoperative complications will occur. Acute care surgeons need to be familiar with the common problems and their management. Although general surgical principles generally apply, diagnoses specific to the various bariatric operations must be considered. There are anatomic considerations which alter management priorities and options for these patients in many instances. These problems present both early or late in the postoperative course. Bariatric operations, in many instances, result in permanent alteration of a patient\u27s anatomy, which can lead to complications at any time during the course of a patient\u27s life. Acute care surgeons diagnosing surgical emergencies in postbariatric operation patients must be familiar with the type of surgery performed, as well as the common postbariatric surgical emergencies. In addition, surgeons must not overlook the common causes of an acute surgical abdomen-acute appendicitis, acute diverticulitis, acute pancreatitis, and gallstone disease-for these are still among the most common etiologies of abdominal pathology in these patients

Quasi-Exact Helical Cone Beam Reconstruction for Micro CT

A cone beam micro-CT system is set up to collect truncated helical cone beam data. This system includes a micro-focal X-ray source, a precision computer-controlled X-Y-Z-theta stage, and an image-intensifier coupled to a large format CCD detector. The helical scanning mode is implemented by rotating and translating the stage while keeping X-ray source and detector stationary. A chunk of bone and a mouse leg are scanned and quasi-exact reconstruction is performed using the approach proposed in J. Hu et al. (2001). This approach introduced the original idea of accessory paths with upper and lower virtual detectors having infinite axial extent. It has a filtered backprojection structure which is desirable in practice and possesses the advantages of being simple to implement and computationally efficient compared to other quasi-exact helical cone beam algorithms for the long object problem