Light-harvesting and the Primary Photochemistry of Roseiflexus castenholzii

Photosynthetic organisms have evolved diverse antennas to harvest light of various qualities and intensities. Anoxygenic phototrophs can have bacteriochlorophyll Qy antenna absorption bands ranging from about 700-1100 nm. This broad range of usable wavelengths has allowed many organisms to thrive in unique environments. Roseiflexus castenholzii is a niche-adapted, filamentous anoxygenic phototroph: FAP) that lacks chlorosomes, the dominant antenna found in all green bacteria. Light-harvesting is realized only in the membrane with BChl a and a variety of carotenoids. Through biochemical and spectroscopic methods, a model for the size and organization of the photosynthetic antenna is presented. Despite the wide distribution of antennas, photochemistry occurs in the reaction center: RC), which can be separated into two groups distinguishable by the identity of the terminal electron acceptor. These are the Fe-S type or type-I and the quinone-type or type -II RCs. All known anoxygenic phototrophs have evolved to utilize only one type of RC. R. castenholzii contains a type-II RC. Through the successful isolation of the RC the kinetics of electron transfer have been investigated by ultrafast pump-probe spectroscopy. Lastly, the energetics of some of the RC cofactors were determined by using redox titrations. The combination of the antenna model and RC kinetics and energetics allows for a nearly complete model of the primary photochemistry in Roseiflexus castenholzii and the expansion of photosynthetic data available among FAPs

Trading with Asia’s Giants

The United States large and sustained trade deficit with Asia raises concerns in the United States about its competitiveness in the region. The purpose of this paper is to examine the patterns of U.S. trade relationships with China and India, and the factors that are influencing their evolution. In contrast to the current public policy debate, the discussion largely addresses how these two economies compare as markets for U.S. exporters. This paper begins by noting that U.S. exports to both countries do appear low relative to the performance of Japan and the EU-15. We examine potential explanations for the weak exports from three different perspectives. First, we analyze the composition of U.S. exports to these economies, and consider how this mix of products compares to those which it appears to be competitive in exporting to the rest of the world. Second, we examine the role of multinational corporations in facilitating the trade flows between the U.S and these two economies. Finally, we employ the use of gravity equations to examine the bilateral trade patterns while controlling for a variety of country specific characteristics, such as distance. In this context, we are also able to analyze the pattern of trade in services as well as the more traditional focus on goods trade.China, India, United States, trade, and exports

Engineering Models to Scale

Main Text The physicist Richard Feynman famously wrote, “What I cannot create, I do not understand,” at the top of his final blackboard. This philosophy has inspired many in the emerging field of synthetic biology, which harnesses the power of biology to rationally engineer biomolecular systems for a variety of purposes, such as whole-cell biosensing and in vivo diagnostics (Slomovic et al., 2015). The “build-to-understand” approach (Elowitz and Lim, 2010) is complementary to top-down systems biology approaches and borrows concepts and techniques from engineering and computer science. By creating biological systems with desired architectures and functions, it aims to test design principles in relative isolation by exploring how biology’s building blocks, such as DNA-encoded genes, can be rearranged and altered to produce different phenotypes. In this issue, Cao et al. use this approach to tackle the question of how self-organizing systems maintain a constant ratio of physical pattern features with changing size, a property known as scale invariance (Cao et al., 2016)

Antimicrobial stewardship practices in Virginia

The Society of Healthcare Epidemiology of America, the Centers for Disease Control and Prevention, and the President\u27s Council of Advisors on Science and Technology recognize the need to combat antimicrobial resistance through the promotion of antimicrobial stewardship programs. Health care facilities in Virginia were surveyed using a 23-item survey focused on facility characteristics and antimicrobial stewardship strategies. Antimicrobial stewardship activities were highly variable and many are missing key personnel and resources

Characterization of atrazine-induced gonadal malformations in African clawed frogs (Xenopus laevis) and comparisons with effects of an androgen antagonist (cyproterone acetate) and exogenous estrogen (17beta-estradiol): Support for the demasculinization/feminization hypothesis.

Atrazine is a potent endocrine disruptor that both chemically castrates and feminizes male amphibians. It depletes androgens in adult frogs and reduces androgen-dependent growth of the larynx in developing male larvae. It also disrupts normal gonadal development and feminizes the gonads of developing males. Gonadal malformations induced by atrazine include hermaphrodites and males with multiple testes [single sex polygonadism (SSP)], and effects occur at concentrations as low as 0.1 ppb (microg/L). Here, we describe the frequencies at which these malformations occur and compare them with morphologies induced by the estrogen, 17beta-estradiol (E2) , and the antiandrogen cyproterone acetate, as a first step in testing the hypothesis that the effects of atrazine are a combination of demasculinization and feminization. The various forms of hermaphroditism did not occur in controls. Nonpigmented ovaries, which occurred at relatively high frequencies in atrazine-treated larvae, were found in four individuals out of more than 400 controls examined (1%). Further, we show that several types of gonadal malformations (SSP and three forms of hermaphroditism) are produced by E2 exposure during gonadal differentiation, whereas a final morphology (nonpigmented ovaries) appears to be the result of chemical castration (disruption of androgen synthesis and/or activity) by atrazine. These experimental findings suggest that atrazine-induced gonadal malformations result from the depletion of androgens and production of estrogens, perhaps subsequent to the induction of aromatase by atrazine, a mechanism established in fish, amphibians, reptiles, and mammals (rodents and humans)

Quantifying speech intelligibility based on crowdsourcing

The intelligibility of speech within media content, e.g., audio or video streams, is an important factor that determines the reach and popularity of the media. Objective measures of audio and speech quality, e.g., PESQ and SII scores, correlate poorly with human assessment. MOS, a widely accepted intelligibility test, is subjective, expensive, and time consuming. Techniques disclosed herein provide an objective measure of the intelligibility of speech within video or audio content. Speech intelligibility scores are calculated based on the edit distance between human speech transcriptions of short clips and transcripts produced by an automatic speech recognizer. The speech intelligibility score is based on human rating and retains objectivity

AUTHENTICATED ACCESS INTO SECURE MEETINGS FOR VIDEO CONFERENCING SYSTEMS

A mechanism is provided to positively identify audio and video endpoints as belonging to a customer\u27s organization. The mechanism configures a meeting to admit Organization Authenticated endpoints without further checks, to require User Authentication, or to require User Verification. The mechanism ensures the endpoint belongs to a person who is also an authorized user in the same organization for secure and expedited access into meetings. An additional mechanism is provided to notify meeting hosts for users trying to enter the meeting where they do not meet the security policies. Further, the mechanism allows a host to determine whether to accept or reject users

Working Better Together: Library, Publisher, and Vendor Perspectives

Amidst more and more publisher content, research tools, and library systems, interoperability—how things work together (for instance, a link resolver and a discovery service, or a data service and a discovery service)—has tremendous implications for workflows for librarians and, ultimately, researchers. With a focus on discoverability, representatives from the library, vendor, and publisher sectors describe their perspectives on cross-sector collaborations and opportunities with a common aim of proactively continuing to refine/improve the researcher experience. Moderated by Mary Somerville from the University of Colorado, Denver, this presentation highlighted perspectives from all three sectors including Maria Collins from North Carolina State University Libraries presenting the library perspective, Nicole Pelsinsky from Serials Solutions presenting from the vendor perspective, and Aaron Wood from Alexander Street Press with the publisher perspective