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Seawater carbonate chemistry and developmental morphology data, shell length dataof mussel larvae grown in static and fluctuating pH treatments, biological data of mussel larvae treated with fluorescent dyes and grown in two pH treatments
No full textCoastal marine ecosystems experience dynamic fluctuations in seawater carbonate chemistry. The importance of this variation in the context of ocean acidification requires knowing what aspect of variability biological processes respond to. We conducted four experiments (ranging from 3 to 22 days) with different variability regimes (pHT 7.4–8.1) assessing the impact of diel fluctuations in carbonate chemistry on the early development of the mussel Mytilus galloprovincialis. Larval shell growth was consistently correlated to mean exposures, regardless of variability regimes, indicating that calcification responds instantaneously to seawater chemistry. Larval development was impacted by timing of exposure, revealing sensitivity of two developmental processes: development of the shell field, and transition from the first to the second larval shell. Fluorescent staining revealed developmental delay of the shell field at low pH, and abnormal development thereof was correlated with hinge defects in D-veligers. This study shows, for the first time, that ocean acidification affects larval soft-tissue development, independent from calcification. Multiple developmental processes additively underpin the teratogenic effect of ocean acidification on bivalve larvae. These results explain why trochophores are the most sensitive life-history stage in marine bivalves and suggest that short-term variability in carbonate chemistry can impact early larval development
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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Coastal Ocean pH Variability in the Context of Global Change Biology
Full text linkAnthropogenic carbon emissions are predicted to alter marine ecosystems. One such change is the decline in ocean pH, known as ocean acidification. Model predictions of ocean acidification have guided biological experiments for more than a decade. Many studies predict negative consequences of future ocean pH on marine species. To understand how species will respond to future conditions, however, knowledge of present-day pH exposures is necessary and often limited. In this dissertation, I described present-day pH variability in three coastal regions and used the data to design laboratory experiments assessing the physiological response of two organisms, sea urchins and mussels, to changing ocean conditions. As recorded by autonomous pH sensors, I found three unique patterns of coastal pH variability. Near-shore Antarctica was characterized by a steep seasonal increase in pH and pH variability during summer phytoplankton blooms. The northern Channel Islands, California, exhibited event-scale and diurnal pH variability due to primary production of phytoplankton and fixed vegetation. Only mild effects from upwelling were detected at the islands, suggesting that this region may become a spatial refuge from extreme low pH in the future. Finally, Oregon was characterized by event-scale decreases in pH due to periodic upwelling events. The results from this research show that many coastal species experience short-term changes in pH that are within the same magnitude of change predicted for ocean acidification by the end of the century. While such present-day exposures to pH variability may promote tolerance of future pH change, these near-shore regions are also characterized by unique patterns of thermal stress. I conducted two studies to investigate the interactive effects of pH and temperature on organismal physiology. First, Antarctic sea urchin, Sterechinus neumayeri, early developmental stages (EDSs) currently experience < 2 °C seasonal warming and may only experience a few degrees of ocean warming over the next 100 years. Despite development under pH and temperatures outside of current exposures, S. neumayeri EDSs exhibited high tolerance of a one-hour heat stress test, suggesting this species may be more resilient to ocean change than previously thought. Second, unlike Antarctic species, intertidal species at mid-latitudes experience daily temperature fluctuations that can exceed four times end-century predictions of ocean warming, due to tidal cycles. In Oregon, upwelling events enhance this temperature range by periodically delivering cold, low pH water to the intertidal zone. Depending on sea water conditions simulating an upwelling event (cold, low pH) or wind relaxation (warm, high pH), the intertidal mussel Mytilus californianus generated different transcriptomic signatures of the cellular heat shock response, following exposure to aerial heat stress. This suggests that future changes in seawater conditions may alter the heat stress tolerance of M. californianus during low tides. The results from this dissertation highlight the importance of designing experiments that reflect species’ present-day and future multi-stressor environment, in order to generate ecologically relevant conclusions. As anthropogenic stressors continue to take hold of coastal seas, understanding the biological consequences is critical for management and conservation efforts
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Biological data of mussel larvae treated with fluorescent dyes and grown in two pH treatments.
No full textDataset: larval responses to pH variability - stainingMussel larvae of Mytilus galloprovincialis were grown in two pH treatments (pH 8.1 and 7.4). Larvae were collected for biological measurements of shell field development and calcification at 35 hours post-fertilization (hpf, trochophore stage). Calcein dye was added to the cultures prior to the start of calcification. Calcofluor is live dye and so was added to sampled larvae at 35 hpf for immediate imaging. Confocal microscopy was used for 3D imaging of larvae. Images were processed in ImageJ. Shell field area was determined as the area stained by calcofluor, on one valve. Calcification area was determined as the area stained by calcein, on one valve.
For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/751258NSF Division of Ocean Sciences (NSF OCE) OCE-152159
Shell length data of mussel larvae grown in static and fluctuating pH treatments
No full textDataset: larval responses to pH variability - sizeMussel larvae of Mytilus galloprovincialis were grown in static and fluctuating pH treatments in a flow-through seawater system. pH was modified with CO2 gas. D-veliger larvae were collected for shell length measurements on various days per experiment. Shell length was determined using microscope photography and analysis in ImageJ.
For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/751282NSF Division of Ocean Sciences (NSF OCE) OCE-152159
Developmental morphology data of mussel larvae grown in static and fluctuating pH treatments
No full textDataset: larval responses to pH variability - developmentMussel larvae of Mytilus galloprovincialis were grown in static and fluctuating pH treatments in a flow-through seawater system. pH was modified with CO2 gas. Larvae were collected on day 3 (D-veliger stage) and staged for developmental success and morphology, using microscope photography.
For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/751232NSF Division of Ocean Sciences (NSF OCE) OCE-152159
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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