1,720,971 research outputs found
Spatially varying selection on shell color phenotype in the flat periwinkle Littorina obtusata
No full textClinal patterns of shell color morph frequencies in the intertidal snail Littorina obtusata present a unique opportunity to explore the effects of variable thermal regime in an ecologically important system. L. obtusata are found in the mid-intertidal region of rocky shores in the northern Atlantic. Temperature and desiccation are well documented as the primary abiotic determinants of distributional patterns in such habitats making them an ideal context for investigation. Further, shell color is predicted to affect response to thermal regime; dark animals are expected to absorb more visible light than lighter animals. We hypothesized that shell color in L. obtusata is under selection via thermal regime and that variation in thermal regime contributes to patterns of shell color morph frequencies across the Gulf of Maine. We found that: (1) Frequencies of shell color variants varied predictably with thermal regime and exhibited pronounced clines at multiple spatial scales. Lighter snails increased in frequency with increasing heat/desiccation stress, while darker snails decreased in frequency. Patterns of differential survivorship under episodic high temperatures were consistent with observed clines. Using a manipulative approach, shell color was shown to directly affect survivorship under such conditions. (2) Analysis of microsatellite variation suggests that populations of L. obtusata in the Gulf of Maine are connected by migration. Additionally, patterns of shell color morph frequencies contrast with variation at microsatellite loci indicating the action of selection on shell color rather than neutral processes alone. (3) Shell color has subtle effects on growth and strong effects on behavior. At spatial scales that reflect behavioral response, light snails were more likely to be found in hotter areas with more desiccation risk and the differences in distribution between color morphs were dependent on environmental conditions. (4) There is considerable morphological variation in Littorina obtusata within the Gulf of Maine. In addition to variation in shell color, there were striking trends in variation in shell patterning and body pigmentation, possibly indicating the action of selection. Taken together, these results provide a compelling example of natural selection and of the potential for variation in thermal regime to affect the evolution of natural populations
Data From: Lighting pathways to success in STEM: A virtual Lab Meeting Program (LaMP) mutually benefits mentees and host labs
No full text<p>Developing robust professional networks can help shape the trajectories of early career scientists. Yet, historical inequities in STEM fields make access to these networks highly variable across academic programs, and senior academics often have little time for mentoring. Here, we illustrate the success of a Virtual Lab Meeting Program (LaMP). In this program, we matched students ("Mentees") with a more experienced researcher ("Mentors") from a research group. The Mentees then attended the Mentors' lab meetings during the academic year with two lab meetings specifically dedicated to the Mentee's professional development. Survey results indicate that Mentees expanded their knowledge of the hidden curriculum as well as their professional network, while only requiring a few extra hours of their Mentor's time over eight months. In addition, host labs benefitted from Mentees sharing new perspectives and knowledge in lab meetings. The diversity of the Mentees was significantly higher than the Mentors, suggesting that the program increased the participation of traditionally underrepresented groups. Finally, we found that providing a stipend was very important to many mentees. We conclude that Virtual Lab Meeting Programs can be an inclusive and cost-effective way to foster trainee development and increase diversity within STEM fields with little additional time commitment.</p><p>Funding provided by: National Science Foundation<br>Crossref Funder Registry ID: https://ror.org/021nxhr62<br>Award Number: 1764316</p><h4>Running the Virtual Lab Meeting Training Program</h4>
<p>The first three months of the program require dedicated time for recruiting and matching Mentees and Mentors (for a summary of program timelines, see Figure 2). One month prior to the start of the academic year, we began to advertise the program by sharing a link to our webpage with potential mentors and mentees (https://rcn-ecs.github.io/VLMTP/; Figure 2). Then, we recruited mentors through a list of personal invitations, listservs, and members of the Evolution in Changing Seas RCN. We completed the process of recruiting 30-40 mentors approximately two weeks after the academic year started (Figure 2). Mentors were required to agree with a document that outlined expectations and best practices for including their Mentee in lab meetings (see Supplemental Materials).</p>
<p>After mentors were recruited, we began the process of recruiting student Mentees. We generated an email contact list to contact as many participants as possible across a diverse group of scientific societies and institutions. The contact list consisted of scientific societies or diversity lists (e.g. Society for Advancement of Chicanos/Hispanics & Native Americans in Science, Diversify Ecology and Evolutionary Biology, Black Women in Ecology Evolution and Marine Science, American Geophysical Union BRIDGE, Association for the Sciences of Limnology and Oceanography Multicultural program, Ecology Society of America SEEDs program, Asian Americans & Pacific Islanders in Geosciences), and a list of 608 professors teaching courses in biology, ecology, or evolution at Historically Black Colleges and Universities, Hispanic Serving Institutions, and Tribal Colleges and Universities. In addition, we advertised to the RCN-ECS listserv and asked colleagues to distribute the information among peers.</p>
<p>To apply, Mentees submitted a 300-word statement that described their current research interests and/or experiences related to the themes under the Evolution in Changing Seas RCN, future career interests, how interactions with a host lab would help to advance their careers and/or support their professional development, and a description of how their participation in this program would help to increase diversity (broadly defined) within the network. They also (i) answered questions about their time zone, (ii) listed their top three choices for mentors, (iii) selected two keywords that described their research interests from a list, (iv) submitted a CV or resume, and (v) optionally answered demographic questions.</p>
<p>Approximately six weeks into the academic year, we closed applications for mentees and started pairing them with mentors. Matching was made by two members of the RCN diversity committee based on the Mentee's academic interests, who they listed as their top three choices for a Mentor, and time zone alignment, taking into account how many Mentees could be assigned to a single Mentor (i.e. usually 1-2 Mentees per lab group). Due to high request rates for well-known Mentors, sometimes we were unable to match a Mentee with one of their top three choices. In the few cases where Mentees did not get their top choices, pairings were made based on affinity between Mentors' and Mentees' research interests. By the second month of the academic year, we had completed the process of pairing mentees with Mentors. Pairs were introduced to each other by email and reminded of the program guidelines and expectations (Supp Doc: Example Email).</p>
<p>Over the course of the academic year, Mentees attended lab meetings on an independent basis. At the end of the academic year, we distributed stipends to students for their participation in the program. To obtain a stipend, students had to provide a letter from their Mentor that stated the student had completed the program requirements.</p>
<h4>Mentee and Mentor Surveys</h4>
<p>At the end of the academic year in 2022, we distributed surveys to Mentees and another survey to Mentors who had participated in the program (for complete surveys, see Supplemental Documents). Both surveys included optional questions on demographic information, year(s) of participation, activities that were part of lab meetings, potential for future collaborations, a Likert scale on how they ranked the program from 1 to 10, and open-ended feedback (Table 1, left column). We also had an open-ended question where participants were encouraged to leave constructive feedback. </p>
<p>The Mentee survey included unique Likert scale questions on whether the program helped them extend their professional network, advance their expertise in subject matter, and how important the stipend was to completing the program. We also asked Mentees what kind of interactions most helped to advance their professional development, what knowledge they gained during the program, and whether they planned to continue interactions with the host lab (Table 1, middle column). </p>
<p>The Mentor survey included questions on the number of Mentees hosted, professional development activities discussed in lab meetings, Mentee contributions to lab meetings, how much time mentors invested in the program, whether Mentees attended lab meetings beyond the program requirements, how many people attended their lab meetings, whether Mentees had 1:1 interactions with other lab members, and Likert questions on whether they agreed with statements regarding continued interactions and benefits of having the Mentee join lab meetings (Table 1, right column).</p>
<h4>IRB Review</h4>
<p>Our surveys were reviewed by the Institutional Review Board at Northeastern University (IRB #: 22-03-33) and were considered exempt (DHHS Review Category: EXEMPT, CATEGORY #2 Revised Common Rule 45CFR46.104(d)(2)(iii)).</p>
Genome-Wide Patterns of Differentiation Among House Mouse Subspecies
Get PDFOne approach to understanding the genetic basis of speciation is to scan the genomes of recently diverged taxa to identify highly differentiated regions. The house mouse, Mus musculus, provides a useful system for the study of speciation. Three subspecies (M. m. castaneus, M. m. domesticus, and M. m. musculus) diverged ∼350 KYA, are distributed parapatrically, show varying degrees of reproductive isolation in laboratory crosses, and hybridize in nature. We sequenced the testes transcriptomes of multiple wild-derived inbred lines from each subspecies to identify highly differentiated regions of the genome, to identify genes showing high expression divergence, and to compare patterns of differentiation among subspecies that have different demographic histories and exhibit different levels of reproductive isolation. Using a sliding-window approach, we found many genomic regions with high levels of sequence differentiation in each of the pairwise comparisons among subspecies. In all comparisons, the X chromosome was more highly differentiated than the autosomes. Sequence differentiation and expression divergence were greater in the M. m. domesticus-M. m. musculus comparison than in either pairwise comparison with M. m. castaneus, which is consistent with laboratory crosses that show the greatest reproductive isolation between M. m. domesticus and M. m. musculus. Coalescent simulations suggest that differences in estimates of effective population size can account for many of the observed patterns. However, there was an excess of highly differentiated regions relative to simulated distributions under a wide range of demographic scenarios. Overlap of some highly differentiated regions with previous results from QTL mapping and hybrid zone studies points to promising candidate regions for reproductive isolation
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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