Assessing the utility and limitations of accelerometers and machine learning approaches in classifying behaviour during lactation in a phocid seal

Background Classifying behaviour with animal-borne accelerometers is quickly becoming a popular tool for remotely observing behavioural states in a variety of species. Most accelerometry work in pinnipeds has focused on classifying behaviour at sea often quantifying behavioural trade-offs associated with foraging and diving in income breeders. Very little work to date has been done to resolve behaviour during the critical period of lactation in a capital breeder. Capital breeding phocids possess finite reserves that they must allocate appropriately to maintain themselves and their new offspring during their brief nursing period. Within this short time, fine-scale behavioural trade-offs can have significant fitness consequences for mother and offspring and must be carefully managed. Here, we present a case study in extracting and classifying lactation behaviours in a wild, breeding pinniped, the grey seal (Halichoerus grypus). Results Using random forest models, we were able to resolve 4 behavioural states that constitute the majority of a female grey seals’ activity budget during lactation. Resting, alert, nursing, and a form of pup interaction were extracted and classified reliably. For the first time, we quantified the potential confounding variance associated with individual differences in a wild context as well as differences due to sampling location in a largely inactive model species. Conclusions At this stage, the majority of a female grey seal’s activity budget was classified well using accelerometers, but some rare and context-dependent behaviours were not well captured. While we did find significant variation between individuals in behavioural mechanics, individuals did not differ significantly within themselves; inter-individual variability should be an important consideration in future efforts. These methods can be extended to other efforts to study grey seals and other pinnipeds who exhibit a capital breeding system. Using accelerometers to classify behaviour during lactation allows for fine-scale assessments of time and energy trade-offs for species with fixed stores

Spatial databases: Generating new insights on office design and human behaviours in the workplace

Space Syntax research has shown how human behaviours in the workplace are shaped by spatial configuration; in turn, evidence-based design practices have highlighted ways in which this data can be used to inform tailor-made solutions in office design. Yet, existing research focuses on either single case studies or comparisons of a few cases on a small scale. Also, each study uses its own methods and metrics which makes it difficult to establish wider patterns beyond single datasets. This paper presents a larger than usual data set on workplaces, which has been collected by Spacelab, a design and consultancy practice based in London. This dataset includes spatial and space usage information such as syntactic analysis and desk occupancy on client companies. It resides in a spatial relational database, allowing for systematic combination of the collected data, useful for doing either deeper analysis, or generating benchmarks and baselines. These insights are not only highly relevant to clients but also give rise to opportunities to generate new insights on office design and human behaviours in the workplace from a research perspective Two main research questions relating to the size of samples are discussed: Firstly, whether large samples are necessary to fully understand phenomena, and secondly, whether behavioural patterns vary across cases. Observation data and syntactic analysis are combined to understand in which areas of an office different activities take place. Observation data is also brought together with the functional allocations of space in order to ask whether activities follow the programme introduced by functions such as meeting rooms, kitchens, workspaces, etc. It is shown that observation data only becomes robust and reliable with longer periods of observations than previously recommended. Three to four full days seems to produce reasonably stable results for desk occupancy, while five full days seemed required for percentages of people walking and interacting. Some surprising findings were revealed regarding the distribution of activities in space, for instance dispelling the myth that interactions happen in corridors and highlighting that interactions tend to occur in rather segregated spaces. While it is argued that predictive power of the analysis varies, first steps towards establishing generic patterns have clearly been taken

Lingin Derived Organic Matter in Georgia Coastal Waters

The importance of riverine- and saltmarsh-derived organic matter to the food web of Georgia coastal waters has been a focus of ecological research over the past thirty years. Studies based on energy budgets, carbon flux measurements, and stable isotope ratios have generally implicated marsh detritus as an important, although not always dominant, source of organic matter within the marshes and adjacent estuaries (Teal 1962, Odum and de la Cruz 1967, Haines 1977, Peterson and Howarth 1987). However, data on the contribution of exported marsh and riverine organic matter to productivity futher offshore, in continental shelf waters off the coast of Georgia, remains equivocal (Chalmers et al. 1985, Hopkinson 1985). Dissolved lignin-derived compounds provide molecular level markers by which to determine the presence of terrestrially-derived organic matter in marine ecosystems. Lignin is found only in vascular plants and has no known oceanic sources. Thus its presence in seawater serves as unequivocal evidence of input of marsh or riverine organic matter, and indeed such lignin-derived material has been found in open ocean water a great distance from its probable point of origin (Meyers-Schulte and Hedges 1986). In this study, we present data on concentrations and distribution of lignin phenols in seawater samples collected during October and November 1987 on the continental shelf of the southeastern U.S., between Cape Hattaras and Cape Canaveral

Reactive stress-coping styles show more variable reproductive expenditure and fitness outcomes

Stress-coping styles dictate how individuals react to stimuli and can be measured by the integrative physiological parameter of resting heart-rate variability (HRV); low resting HRV indicating proactive coping styles, while high resting HRV typifies reactive individuals. Over 5 successive breeding seasons we measured resting HRV of 57 lactating grey seals. Mothers showed consistent individual differences in resting HRV across years. We asked whether proactive and reactive mothers differed in their patterns of maternal expenditure and short-term fitness outcomes within seasons, using maternal daily mass loss rate to indicate expenditure, and pup daily mass gain to indicate within season fitness outcomes. We found no difference in average rates of maternal daily mass loss or pup daily mass gain between proactive and reactive mothers. However, reactive mothers deviated more from the sample mean for maternal daily mass and pup daily mass gain than proactive mothers. Thus, while proactive mothers exhibit average expenditure strategies with average outcomes, expenditure varies much more among reactive mothers with more variable outcomes. Overall, however, mean fitness was equal across coping styles, providing a mechanism for maintaining coping style diversity within populations. Variability in reactive mothers’ expenditures and success is likely a product of their attempts to match phenotype to prevailing environmental conditions, achieved with varying degrees of success

Distribution of Terrestrially Derived Dissolved Organic Matter on the Southeastern United States Continental Shelf

Dissolved lignin-derived compounds in seawater indicate the presence of organic matter originating from vascular plants and therefore from terrestrial (upland and coastal marsh) ecosystems. We used a hydrophobic resin to concentrate lignin-rich humic substances and to determine concentrations of lignin oxidation products (vanillyl lignin phenols) for waters of the continental shelf of the southeastern U.S. Lignin phenol concentrations ranged from 0.05 to 4.2µg liter‒1 and accounted for 0.002–0.13% of the total dissolved organic carbon (DOC) pool in continental shelf waters. Dissolved lignin concentrations were generally highest near the shore and in those areas receiving greatest river and marsh discharge. Concentrations varied on both short-term (weekly) and seasonal time scales, however, indicating that the contribution of terrestrially derived dissolved organic matter to the C budget of the shelf is quite variable. Salinity (\u3e 31‰) was significantly correlated (negatively) with lignin phenol concentrations during three of four cruises, suggesting largely conservative mixing of lignin-derived material on the shelf In selected rivers and salt marshes contributing terrestrially derived organic matter to the continental shelf, lignin phenol C accounted for 0.14–1.0% of the DOC. A simple mixing model which assumes no biological or physical sinks of lignin-derived material during transport from terrestrial sources to the shelf predicts that an average of 6–36% of nearshore DOC derives from terrestrial ecosystems, depending on whether the terrestrial end-member (lignin source) is assumed to be a river or a salt marsh, while 5–26% of inner shelf DOC and 3–18% of mid- to outer-shelf DOC is of terrestrial origin

Potential overestimation of community respiration in the western Pacific boundary ocean : what causes the putative net heterotrophy in oligotrophic systems?

Microbial metabolism is of great importance in affecting the efficiency of biological pump and global carbon cycles. However, the metabolic state of the oligotrophic ocean, the largest biome on Earth, remains contentious. We examined the planktonic and bacterial metabolism using in vitro incubations along the western Pacific boundary during September and October 2016. The integrated gross primary production (GPP) of the photic zone exhibited higher values in the region of 2°–8°N along 130°E and the western Luzon Strait, which is consistent with the regional variability of nutrients in the different ocean provinces. Spatially, the community respiration (CR) was less variable than the GPP and slightly exceeded the GPP at most of the sampling stations. Overall, the in vitro incubation results suggest a prevailing heterotrophic state in this region. A comparison of the metabolic rates from the in vitro incubations with recently published biogeochemical model results in the same region shows that our observed GPP values were close to those predicted by the model, but the measured CR was approximately 30% higher than the modeled values. We also found that most of the in vitro CR estimates were higher than the upper range of the empirical CR estimated from the sum of the contributions of the main trophic groups. Conversely, the estimates of the empirical CR support the rationality of the CR predicted by the biogeochemical model. In general, the results indicate that systematic net heterotrophy is more likely a result of the overestimation of CR measured by the light–dark bottle incubation experiments, although the exact cause of the methodological problem remains unknown

Measurement of parity-nonconserving rotation of neutron spin in the 0.734-eV p-wave resonance of 139La^{139}La

The parity nonconserving spin rotation of neutrons in the 0.734-eV p-wave resonance of $^{139}La$ was measured with the neutron transmission method. Two optically polarized $^3He$ cells were used before and behind a a 5-cm long $^{139}La$ target as a polarizer and an analyzer of neutron spin. The rotation angle was carefully measured by flipping the direction of $^3He$ polarization in the polarizer in sequence. The peak-to-peak value of the spin rotation was found to be $(7.4 \pm 1.1) \times 10^{-3}$ rad/cm which was consistent with the previous experiments. But the result was statisticallly improved. The s-p mixing model gives the weak matrix element as $xW = (1.71 \pm 0.25)$ meV. The value agrees well with the one deduced from the parity-nonconserving longitudinal asymmetry in the same resonance