905 research outputs found
Assessing Changes in Freshwater and Marine Food Web Connections Following Restoration on the Penobscot River, Maine, Using Stable Isotope Analysis
Oiadromous fish provide ecological subsidies to freshwater and marine food
webs, connecting both ecosystems. A main goal of the Penobscot River Restoration
Project was to increase connectivity between food webs by removing two mainstem
dams, improving fish passage, and reintroducing river herring through stocking.
Oiadromous fish now reach historic spawning habitat that was not accessible for
centuries. As a result, river herring runs in the Penobscot River increased from
2,336 fish in 2009 to over 3 million fish by 2018. To assess food web connectivity in
the Penobscot watershed, I analyzed stable isotopes from samples collected before
(2009-2010) and after (2020-2021) dam removals by sampling species ranging in
trophic level from piscivorous fish to baseline primary consumers from three
mainstem and three major upstream tributary sites. I targeted top fish predators
that can consume adult river herring directly. Pre-restoration, I found little evidence
of marine derived nutrient (MON) assimilation in freshwater food webs, with the
exception of a mainstem site below all dams. Post-restoration, MON assimilation
increased only below what is now the lowest dam on the river, likely due to
migration delays aggregating more fish for a longer period of time than in free-flowing
river sections. Where changes in MON assimilation occurred, I saw evidence
of bottom-up enrichment of the food web. This pattern of enrichment has been
measured in smaller rivers with spawning runs dominated by river herring. These
results may be one of the first in a river of this size (watershed area 22,300 km2)
and restoration of this magnitude, suggesting that even in larger rivers with greater
dilution effects, effects of river herring on the transfer of nutrients from marine to
freshwaters are detectable. In the Penobscot Watershed, river herring currently
dominates the sea-run fish population but only comprise 20% of conservative
estimates of historic run size based on spawning habitat available before dam
construction. As sea-run species increase in abundance, I expect MDN to be
detectable beyond points of aggregation
Clinically Competent Peers and Support for Education: Structures and Practices that Work
The preceding excerpts from interviews with staff nurses in magnet hospitals reflect the key messages reported in this article. (Unless otherwise stated, all excerpts are from staff nurses who were interviewed for this study. The professional role of the speaker is cited for physicians [MDs] and nurse managers [NMs].) Competency is multifaceted and evident through actions. Clinically competent peers is all about competent performance, not the potential for performance. Both performance and potential are important for quality patient care, but here we focus solely on what others see or hear that leads to the judgment or conclusion that nurses on the front line in acute care hospitals are clinically competent
Moral Framing and Ideological Bias of News
News outlets are a primary source for many people to learn what is going on
in the world. However, outlets with different political slants, when talking
about the same news story, usually emphasize various aspects and choose their
language framing differently. This framing implicitly shows their biases and
also affects the reader's opinion and understanding. Therefore, understanding
the framing in the news stories is fundamental for realizing what kind of view
the writer is conveying with each news story. In this paper, we describe
methods for characterizing moral frames in the news. We capture the frames
based on the Moral Foundation Theory. This theory is a psychological concept
which explains how every kind of morality and opinion can be summarized and
presented with five main dimensions. We propose an unsupervised method that
extracts the framing Bias and the framing Intensity without any external
framing annotations provided. We validate the performance on an annotated
twitter dataset and then use it to quantify the framing bias and partisanship
of news
Behind film performance in China’s changing institutional context:The impact of signals
Grounded in signaling theory, this paper investigates the signals reflecting product quality, innovativeness, reputation and cultural background which influence film performance, i.e. film survival (duration on cinema screen) and box office success, in China’s changing institutional context. This market has grown substantially and still possesses potential for further development. However, China’s unique institutional context presents challenges. By examining an expanded range of potential signals, two of which have not previously been examined in the literature, namely imported films and enhanced format film formats such as 3D and IMAX, we develop a conceptual framework and argue that signaling theory needs to be combined with institutional context. Similar to findings for film industries in other countries, we find quality and reputational signals including budget, star power, sequels, and online consumer reviews to be important in China. However, unique results are also revealed. Chinese consumers react to an innovativeness signal in that they are specifically attracted to enhanced format films. Film award nominations and prizes are insignificant reputational signals. Once other signals are taken into account, imported films on average do not perform as well as domestic films. We link these findings to China’s unique institutional setting and offer important implications for management, recognizing the challenges to film companies of competing in an increasingly globalized market. The paper is also of relevance to policymakers given their continued efforts in shaping the development of China’s film industry
Step-wise evolution of complex chemical defenses in millipedes: a phylogenomic approach
With fossil representatives from the Silurian capable of respiring atmospheric oxygen, millipedes
are among the oldest terrestrial animals, and likely the first to acquire diverse and complex chemical defenses against predators. Exploring the origin of complex adaptive traits is critical for understanding the evolution of Earth’s biological complexity, and chemical defense evolution serves as an ideal
study system. The classic explanation for the evolution of complexity is by gradual increase from simple to complex, passing through intermediate “stepping stone� states. Here we present the first phylogenetic-based study of the evolution of complex chemical defenses in millipedes by generating the largest genomic-based phylogenetic dataset ever assembled for the group. Our phylogenomic results demonstrate that chemical complexity shows a clear pattern of escalation through time. New pathways are added in a stepwise pattern, leading to greater chemical complexity, independently in a number of derived lineages. This complexity gradually increased through time, leading to the advent of three distantly related chemically complex evolutionary lineages, each uniquely characteristic of each of the respective millipede groups
Fast Benchtop Fabrication of Laminar Flow Chambers for Advanced Microscopy Techniques
Background: Fluid handling technology is acquiring an ever more prominent place in laboratory science whether it is in simple buffer exchange systems, perfusion chambers, or advanced microfluidic devices. Many of these applications remain the providence of laboratories at large institutions with a great deal of expertise and specialized equipment. Even with the expansion of these techniques, limitations remain that frequently prevent the coupling of controlled fluid flow with other technologies, such as coupling microfluidics and high-resolution position and force measurements by optical trapping microscopy. Method: Here we present a method for fabrication of multiple-input laminar flow devices that are optically clear [glass] on each face, chemically inert, reusable, inexpensive, and can be fabricated on the benchtop in approximately one hour. Further these devices are designed to allow flow regulation by a simple gravity method thus requiring no specialized equipment to drive flow. Here we use these devices to perform total internal reflection fluorescence microscopy measurements as well as position sensitive optical trapping experiments. Significance: Flow chamber technology needs to be more accessible to the general scientific community. The method presented here is versatile and robust. These devices use standard slides and coverslips making them compatible with nearly all types and models of light microscopes. These devices meet the needs of groups doing advanced optical trapping experiments, but could also be adapted by nearly any lab that has a function for solution flow coupled with microscopy
Utility of multispectral imaging for nuclear classification of routine clinical histopathology imagery
<p>Abstract</p> <p>Background</p> <p>We present an analysis of the utility of multispectral versus standard RGB imagery for routine H&E stained histopathology images, in particular for pixel-level classification of nuclei. Our multispectral imagery has 29 spectral bands, spaced 10 nm within the visual range of 420–700 nm. It has been hypothesized that the additional spectral bands contain further information useful for classification as compared to the 3 standard bands of RGB imagery. We present analyses of our data designed to test this hypothesis.</p> <p>Results</p> <p>For classification using all available image bands, we find the best performance (equal tradeoff between detection rate and false alarm rate) is obtained from either the multispectral or our "ccd" RGB imagery, with an overall increase in performance of 0.79% compared to the next best performing image type. For classification using single image bands, the single best multispectral band (in the red portion of the spectrum) gave a performance increase of 0.57%, compared to performance of the single best RGB band (red). Additionally, red bands had the highest coefficients/preference in our classifiers. Principal components analysis of the multispectral imagery indicates only two significant image bands, which is not surprising given the presence of two stains.</p> <p>Conclusion</p> <p>Our results indicate that multispectral imagery for routine H&E stained histopathology provides minimal additional spectral information for a pixel-level nuclear classification task than would standard RGB imagery.</p
Search for the Decays B^0 -> D^{(*)+} D^{(*)-}
Using the CLEO-II data set we have searched for the Cabibbo-suppressed decays
B^0 -> D^{(*)+} D^{(*)-}. For the decay B^0 -> D^{*+} D^{*-}, we observe one
candidate signal event, with an expected background of 0.022 +/- 0.011 events.
This yield corresponds to a branching fraction of Br(B^0 -> D^{*+} D^{*-}) =
(5.3^{+7.1}_{-3.7}(stat) +/- 1.0(syst)) x 10^{-4} and an upper limit of Br(B^0
-> D^{*+} D^{*-}) D^{*\pm} D^\mp and
B^0 -> D^+ D^-, no significant excess of signal above the expected background
level is seen, and we calculate the 90% CL upper limits on the branching
fractions to be Br(B^0 -> D^{*\pm} D^\mp) D^+
D^-) < 1.2 x 10^{-3}.Comment: 12 page postscript file also available through
http://w4.lns.cornell.edu/public/CLNS, submitted to Physical Review Letter
Asteroseismology and Interferometry
Asteroseismology provides us with a unique opportunity to improve our
understanding of stellar structure and evolution. Recent developments,
including the first systematic studies of solar-like pulsators, have boosted
the impact of this field of research within Astrophysics and have led to a
significant increase in the size of the research community. In the present
paper we start by reviewing the basic observational and theoretical properties
of classical and solar-like pulsators and present results from some of the most
recent and outstanding studies of these stars. We centre our review on those
classes of pulsators for which interferometric studies are expected to provide
a significant input. We discuss current limitations to asteroseismic studies,
including difficulties in mode identification and in the accurate determination
of global parameters of pulsating stars, and, after a brief review of those
aspects of interferometry that are most relevant in this context, anticipate
how interferometric observations may contribute to overcome these limitations.
Moreover, we present results of recent pilot studies of pulsating stars
involving both asteroseismic and interferometric constraints and look into the
future, summarizing ongoing efforts concerning the development of future
instruments and satellite missions which are expected to have an impact in this
field of research.Comment: Version as published in The Astronomy and Astrophysics Review, Volume
14, Issue 3-4, pp. 217-36
Teaching and learning quality of life in urban studies:A mixed-methods approach with walking interviews
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