Dive behavior represents multiple ecological functions for marine mammals, but our understanding of dive characteristics is typically limited by the resolution or longevity of tagging studies. Knowledge on the time-depth structures of dives can provide insight into the behaviors represented by vertical movements; furthering our understanding of the ecological importance of habitats occupied, seasonal shifts in activity, and the energetic consequences of targeting prey at a given depth. Given our incomplete understanding of Eastern Beaufort Sea (EBS) beluga whale behavior over an annual cycle, we aimed to characterize dives made by belugas, with a focus on analyzing shifts in foraging strategies. Objectives were to (i) characterize and classify the range of beluga-specific dive types over an annual cycle, (ii) propose dive functions based on optimal foraging theory, physiology, and association with environmental variables, and (iii) identify whether belugas undergo seasonal shifts in the frequency of dives associated with variable foraging strategies. Satellite-linked time-depth-recorders (TDRs) were attached to 13 male belugas from the EBS population in 2018 and 2019, and depth data were collected in time series at a 75 s sampling interval. Tags collected data for between 13 and 357 days, including three tags which collected data across all months. A total of 90,211 dives were identified and characterized by twelve time and depth metrics and classified into eight dive types using a Gaussian mixed modeling and hierarchical clustering analysis approach. Dive structures identify various seasonal behaviors and indicate year-round foraging. Shallower and more frequent diving during winter in the Bering Sea indicate foraging may be energetically cheaper, but less rewarding than deeper diving during summer in the Beaufort Sea and Arctic Archipelago, which frequently exceeded the aerobic dive limit previously calculated for this population. Structure, frequency and association with environmental variables supports the use of other dives in recovery, transiting, and navigating through sea ice. The current study provides the first comprehensive description of the year-round dive structures of any beluga population, providing baseline information to allow improved characterization and to monitor how this population may respond to environmental change and increasing anthropogenic stressors.

We describe a program for nding closed form solutions to nite sums. The program was built to test the applicability of the proof planning search control technique in a domain of mathematics outwith induction. This experiment was successful. The series summing program extends previous work in this area and was built in a short time just by providing new series summing methods to our existing inductive theorem proving system CLAM.One surprising discovery was the usefulness of the ripple tactic in summing series. Rippling is the key tactic for controlling inductive proofs, and was previously thought to be specialised to such proofs. However, it turns out to be the key sub-tactic used by all the main tactics for summing series. The only change required was that it had to be supplemented by a di erence matching algorithm to set up some initial meta-level annotations to guide the rippling process. In inductive proofs these annotations are provided by the application of mathematical induction. This evidence suggests that rippling, supplemented by di erence matching, will nd wide application in controlling mathematical proofs.

We have updated Ferree and Hall's (1990) study of the way gender and race are constructed through pictures in introductory sociology textbooks. Ferree and Hall looked at 33 textbooks published between 1982 and 1988. We replicated their study by examining 3,085 illustrations in a sample of 27 textbooks, most of which were published between 2002 and 2006. We found important areas of progress in the presentation of both gender and race as well as significant areas of stasis. The face of society we found depicted in contemporary textbooks was distinctly less likely to be that of a white man, very prominent in the 1980s texts, and much more likely to be that of a minority woman. Thus, while only 34 percent of the pictures of identifiable individuals in the textbooks examined by Ferree and Hall were of women, almost 50 percent of such pictures were of women in the recent texts. Moreover, while the percentage of white men portrayed dropped from about 45 percent to 30 percent, the percentage of portrayals of minority women rose from about 11 percent to 22 percent. Another sign of progress has been the decreasing likelihood of textbooks to depict race and gender as being nonover-lapping categories: while women of color apparently “had” only race in the sample examined by Ferree and Hall, they “had” both gender and race in the sample we studied. Still, our examination of pictures as a whole as a unit of analysis found that blacks continue to be more likely than any other racial group to be depicted in the presence of other racial groups and, thus, to idealize the degree of social integration in American society. We also still see non-white women enjoying very little (in fact, no) visibility in sections devoted to theory, despite developments in feminist theory, generally, and multicultural feminist, specifically. In general, though, our analysis suggests that the various criticisms of introductory texts that have appeared in this forum and others can have an impact on the content of those texts and, by extension, the sociology we teach.

In 2015, as part of the Ocean Tracking Network's bioprobe initiative, 20 grey seals (Halichoerus grypus) were tagged with a high-resolution (> 30 Hz) inertial tags (> 30 Hz), a depth-temperature satellite tag (0.1 Hz), and an acoustic transceiver on Sable Island for 6 months. Comparable to similar large-scale studies in movement ecology, the unprecedented size of the data (gigabytes for a single seal) collected by these instruments raises new challenges in efficient database management. Here we propose the utility of Postgres and netCDF for storing the biotelemetry data and associated metadata. While it was possible to write the lower-resolution (acoustic and satellite) data to a Postgres database, netCDF was chosen as the format for the high-resolution movement (acceleration and inertial) records. Even without access to cluster computing, data could be efficiently (CPU time) recorded, as 920 million records were written in < 3 hours. ERDDAP was used to access and link the different datastreams with a user-friendly Application Programming Interface. This approach compresses the data to a fifth of its original size, and storing the data in a tree-like structure enables easy access and visualization for the end user.PeerJ Preprints | https://doi.org/10.7287/peerj.preprints.26731v1 | CC BY 4.0 Open Access |