Invasion of two \u3ci\u3eLabidesthes\u3c/i\u3e species through the Tennessee-Tombigbee Waterway in Mississippi

We re-identified the collections of Labidesthes sicculus at Mississippi Museum of Natural Science after a 2015 publication by Werneke and Armbruster elevated Labidesthes vanhyningi to the full species level. Following re-examination of specimens, 64% were identified as L. vanhyningi and 36% were identified as L. sicculus. During our study, a chronological review of the distribution of both species suggested bi-directional invasion through the Tennessee-Tombigbee Waterway. Prior to the connection of the two drainages, the only Labidesthes located in the Tennessee drainage was L. sicculus, where as L. vanhyningi was allopatric within the Tombigbee drainage. However, following canal construction, we noted 34 collections of L. sicculus in the Tombigbee drainage and two collections of L. vanhyningi in the Tennessee drainage. Our findings are consistent with previous studies that have noted silverside species utilizing canal construction to expand their range. Our study adds to the growing literature on the impacts of natural stream channel alteration on native fish communities and documents the importance of natural science collections

The Mechanization of Philosophy Between 1300-1700

Standard histories of the development of modern science and philosophy has it that the mechanical philosophy was driven by changes in physics that then required a re-conceptualization of the metaphysics of substance. We contest that this view is backwards. The revisions of the metaphysics of substance occurred in the 14th century and it underlined the well-known changes in physics in the 15th and 16th centuries, which gave rise to mechanical philosophy in the 17th century

A profile of the online dissemination of national influenza surveillance data

<p>Abstract</p> <p>Background</p> <p>Influenza surveillance systems provide important and timely information to health service providers on trends in the circulation of influenza virus and other upper respiratory tract infections. Online dissemination of surveillance data is useful for risk communication to health care professionals, the media and the general public. We reviewed national influenza surveillance websites from around the world to describe the main features of surveillance data dissemination.</p> <p>Methods</p> <p>We searched for national influenza surveillance websites for every country and reviewed the resulting sites where available during the period from November 2008 through February 2009. Literature about influenza surveillance was searched at MEDLINE for relevant hyperlinks to related websites. Non-English websites were translated into English using human translators or Google language tools.</p> <p>Results</p> <p>A total of 70 national influenza surveillance websites were identified. The percentage of developing countries with surveillance websites was lower than that of developed countries (22% versus 57% respectively). Most of the websites (74%) were in English or provided an English version. The most common surveillance methods included influenza-like illness consultation rates in primary care settings (89%) and laboratory surveillance (44%). Most websites (70%) provided data within a static report format and 66% of the websites provided data with at least weekly resolution.</p> <p>Conclusion</p> <p>Appropriate dissemination of surveillance data is important to maximize the utility of collected data. There may be room for improvement in the style and content of the dissemination of influenza data to health care professionals and the general public.</p

Assessing The Impact Of Introductory Physics For The Life Sciences On Students’ Ability To Build Complex Models

A central goal of introductory physics for the life sciences (IPLS) is to prepare students to use physics to model and analyze biological situations, a skill of increasing importance for their future studies and careers. Here we report our findings on life science students’ ability to carry out a sophisticated biological modeling task at the end of first-semester introductory physics. Some students were enrolled in a standard course (N = 34), and some in an IPLS course (N = 61); both courses were taught with active learning, used calculus, and included the same core physics concepts. Compared to those who took the standard course, we found that the IPLS students were significantly more successful at building a model that combined ideas in a manner they had not previously seen, and at making complex decisions about how to apply an equation to a particular physical situation, although both groups displayed similar success at solving simpler problems. Both groups identified and applied simple models that they had previously used in very similar contexts, and executed straightforward calculations, at statistically indistinguishable rates. We report both our findings and the rationale behind the development of the task, in the hopes that others may find this task either a valuable tool or a starting point to develop other such tasks. Further study is needed to determine the basis for the IPLS students’ stronger performance—namely, what aspects of the IPLS course support these students to be better prepared to do such modeling—as well as whether biological settings are important for IPLS students to succeed in flexible model building, and whether the ability to employ models flexibly persists over time

Demonstration of an electric field conjugation algorithm for improved starlight rejection through a single mode optical fiber

Linking a coronagraph instrument to a spectrograph via a single mode optical fiber is a pathway towards detailed characterization of exoplanet atmospheres with current and future ground- and space-based telescopes. However, given the extreme brightness ratio and small angular separation between planets and their host stars, the planet signal-to-noise ratio will likely be limited by the unwanted coupling of starlight into the fiber. To address this issue, we utilize a wavefront control loop and a deformable mirror to systematically reject starlight from the fiber by measuring what is transmitted through the fiber. The wavefront control algorithm is based on the formalism of electric field conjugation (EFC), which in our case accounts for the spatial mode selectivity of the fiber. This is achieved by using a control output that is the overlap integral of the electric field with the fundamental mode of a single mode fiber. This quantity can be estimated by pair-wise image plane probes injected using a deformable mirror. We present simulation and laboratory results that demonstrate our approach offers a significant improvement in starlight suppression through the fiber relative to a conventional EFC controller. With our experimental setup, which provides an initial normalized intensity of $3\times10^{-4}$ in the fiber at an angular separation of $4\lambda/D$, we obtain a final normalized intensity of $3\times 10^{-6}$ in monochromatic light at $\lambda=635$~nm through the fiber (100x suppression factor) and $2\times 10^{-5}$ in $\Delta\lambda/\lambda=8\%$ broadband light about $\lambda=625$~nm (10x suppression factor). The fiber-based approach improves the sensitivity of spectral measurements at high contrast and may serve as an integral part of future space-based exoplanet imaging missions as well as ground-based instruments

c-di-GMP modulates type IV MSHA pilus retraction and surface attachment in Vibrio cholerae.

Biofilm formation by Vibrio cholerae facilitates environmental persistence, and hyperinfectivity within the host. Biofilm formation is regulated by 3',5'-cyclic diguanylate (c-di-GMP) and requires production of the type IV mannose-sensitive hemagglutinin (MSHA) pilus. Here, we show that the MSHA pilus is a dynamic extendable and retractable system, and its activity is directly controlled by c-di-GMP. The interaction between c-di-GMP and the ATPase MshE promotes pilus extension, whereas low levels of c-di-GMP correlate with enhanced retraction. Loss of retraction facilitated by the ATPase PilT increases near-surface roaming motility, and impairs initial surface attachment. However, prolonged retraction upon surface attachment results in reduced MSHA-mediated surface anchoring and increased levels of detachment. Our results indicate that c-di-GMP directly controls MshE activity, thus regulating MSHA pilus extension and retraction dynamics, and modulating V. cholerae surface attachment and colonization