Chimpanzee pant-hoots encode individual information more reliably than group differences.

Vocal learning, the ability to modify the acoustic structure of vocalizations based on social experience, is a fundamental feature of speech in humans (Homo sapiens). While vocal learning is common in taxa such as songbirds and whales, the vocal learning capacities of nonhuman primates appear more limited. Intriguingly, evidence for vocal learning has been reported in chimpanzees (Pan troglodytes), for example, in the form of regional variation ("dialects") in the "pant-hoot" calls. This suggests that some capacity for vocal learning may be an ancient feature of the Pan-Homo clade. Nonetheless, reported differences have been subtle, with intercommunity variation representing only a small portion of the total acoustic variation. To gain further insights into the extent of regional variation in chimpanzee vocalizations, we performed an analysis of pant-hoots from chimpanzees in the neighboring Kasekela and Mitumba communities at Gombe National Park, Tanzania, and the geographically distant Kanyawara community at Kibale National Park, Uganda. We did not find any statistically significant differences between the neighboring communities at Gombe or among geographically distant communities. Furthermore, we found differences among individuals in all communities. Hence, the variation in chimpanzee pant-hoots reflected individual differences, rather than group differences. Thus, we did not find evidence of dialects in this population, suggesting that extensive vocal learning emerged only after the lineages of Homo and Pan diverged.

Proprioceptive afferents differentially contribute to effortful perception of object heaviness and length.

When humans handle a tool, such as a tennis racket or hammer, for the first time, they often wield it to determine its inertial properties. The mechanisms that contribute to perception of inertial properties are not fully understood. The present study's goal was to investigate how proprioceptive afferents contribute to effortful perception of heaviness and length of a manually wielded object in the absence of vision. Blindfolded participants manually wielded specially designed objects with different mass, the static moment, and the moment of inertia at different wrist angles and angular kinematics. These manipulations elicited different tonic and rhythmic activity levels in the muscle spindles of the wrist, allowing us to relate differences in muscle activity to perceptual judgments of heaviness and length. Perception of heaviness and length depended on an object's static moment and the moment of inertia, respectively. Manipulations of wrist angle and angular kinematics affected perceived heaviness and length in distinct ways. Ulnar deviation resulted in an object being perceived heavier but shorter. Compared to static holding, wielding the object resulted in it being perceived heavier but wielding did not affect perceived length. These results suggest that proprioceptive afferents differentially contribute to effortful perception of object heaviness and length. Critically, the role of afferent is specific to the mechanical variable used to derive a given object property. These findings open a new possibility of studies on the link between physiology, and different mechanical variables picked up by the perceptual system.

Self-organization of laterally asymmetrical movements as a consequence of space-time optimization.

Laterally asymmetrical movements are ubiquitous among organisms. A bilaterally symmetrical organism cannot maneuver through a two- or three-dimensional space unless and until one side of its body leads, because the forces that cause the movements of the body are generated within the body. One question follows: are there any costs or benefits of laterally asymmetrical movements? We test whether directionally consistent laterally asymmetrical movements at different levels of organization of movements (at the individual, and not the population level) can work synergistically. We show-by means of a hypothetical system resembling a humanoid robot-that a laterally asymmetrical movement at a lower level of organization of movements can stimulate laterally asymmetrical movements that are directionally consistent at consecutive higher levels. We show-by comparing two hypothetical systems, incorporating laterally symmetrical and asymmetrical movements, respectively-that the asymmetrical system outperforms the symmetrical system by optimizing space and time and that this space-time advantage increases with the increasing complexity of the task. Together, these results suggest that laterally asymmetrical movements can self-organize as a consequence of space-time optimization.

Division of labor in hand usage in free-ranging bonnet macaques, Macaca radiata.

Primates exhibit laterality in hand usage either in terms of (a) hand with which an individual solves a task or while solving a task that requires both hands, executes the most complex action, that is, "hand preference," or (b) hand with which an individual executes actions most efficiently, that is, "hand performance." Observations from previous studies indicate that laterality in hand usage might reflect specialization of the two hands for accomplishing tasks that require maneuvering dexterity or physical strength. However, no existing study has investigated handedness with regard to this possibility. In this study, we examined laterality in hand usage in urban free-ranging bonnet macaques, Macaca radiata with regard to the above possibility. While solving four distinct food extraction tasks which varied in the number of steps involved in the food extraction process and the dexterity required in executing the individual steps, the macaques consistently used one hand for extracting food (i.e., task requiring maneuvering dexterity)-the "maneuvering" hand, and the other hand for supporting the body (i.e., task requiring physical strength)-the "supporting" hand. Analogously, the macaques used the maneuvering hand for the spontaneous routine activities that involved maneuvering in three-dimensional space, such as grooming, and hitting an opponent during an agonistic interaction, and the supporting hand for those that required physical strength, such as pulling the body up while climbing. Moreover, while solving a task that ergonomically forced the usage of a particular hand, the macaques extracted food faster with the maneuvering hand as compared to the supporting hand, demonstrating the higher maneuvering dexterity of the maneuvering hand. As opposed to the conventional ideas of handedness in non-human primates, these observations demonstrate division of labor between the two hands marked by their consistent usage across spontaneous and experimental tasks requiring maneuvering in three-dimensional space or those requiring physical strength.

Differences in expression of male aggression between wild bonobos and chimpanzees.

Researchers investigating the evolution of human aggression look to our closest living relatives, bonobos (Pan paniscus) and chimpanzees (Pan troglodytes), as valuable sources of comparative data.1,2 Males in the two species exhibit contrasting patterns: male chimpanzees sexually coerce females3,4,5,6,7,8 and sometimes kill conspecifics,9,10,11,12 whereas male bonobos exhibit less sexual coercion13,14 and no reported killing.13 Among the various attempts to explain these species differences, the self-domestication hypothesis proposes negative fitness consequences of male aggression in bonobos.2,15,16 Nonetheless, the extent to which these species differ in overall rates of aggression remains unclear due to insufficiently comparable observation methods.17,18,19,20,21,22,23 We used 14 community-years of focal follow data-the gold standard for observational studies24-to compare rates of male aggression in 3 bonobo communities at the Kokolopori Bonobo Reserve, Democratic Republic of Congo, and 2 chimpanzee communities at Gombe National Park, Tanzania. As expected, given that females commonly outrank males, we found that bonobos exhibited lower rates of male-female aggression and higher rates of female-male aggression than chimpanzees. Surprisingly, we found higher rates of male-male aggression among bonobos than chimpanzees even when limiting analyses to contact aggression. In both species, more aggressive males obtained higher mating success. Although our findings indicate that the frequency of male-male aggression does not parallel species difference in its intensity, they support the view that contrary to male chimpanzees, whose reproductive success depends on strong coalitions, male bonobos have more individualistic reproductive strategies.25.

OpenApePose, a database of annotated ape photographs for pose estimation.

Because of their close relationship with humans, non-human apes (chimpanzees, bonobos, gorillas, orangutans, and gibbons, including siamangs) are of great scientific interest. The goal of understanding their complex behavior would be greatly advanced by the ability to perform video-based pose tracking. Tracking, however, requires high-quality annotated datasets of ape photographs. Here we present OpenApePose, a new public dataset of 71,868 photographs, annotated with 16 body landmarks of six ape species in naturalistic contexts. We show that a standard deep net (HRNet-W48) trained on ape photos can reliably track out-of-sample ape photos better than networks trained on monkeys (specifically, the OpenMonkeyPose dataset) and on humans (COCO) can. This trained network can track apes almost as well as the other networks can track their respective taxa, and models trained without one of the six ape species can track the held-out species better than the monkey and human models can. Ultimately, the results of our analyses highlight the importance of large, specialized databases for animal tracking systems and confirm the utility of our new ape database.

All animals carry out a wide range of behaviors in everyday life, such as feeding and communicating with one another. Understanding the complex behavior of non-human apes such as chimpanzees, bonobos, gorillas, orangutans, and various gibbons is of great interest to scientists due to their close relationship with humans. Each behavior is made up of a string of poses that an animal makes with its body. To analyze them in a reliable and consistent way, scientists have developed automated pose estimation methods that determine the position of body parts from photographs and videos. While these systems require minimal external input to perform, they need to be trained on a large dataset of high-quality annotated images of the target animals to teach the system what to look for. So far, scientists have relied on systems trained on monkey and human images to analyze ape data. However, apes are particularly challenging to track because their body textures are uniform, and they have a large number of poses. Therefore, for the most accurate tracking of ape behaviors, a dedicated training dataset of annotated ape images is required. Desai et al. filled this gap by creating the "OpenApePose" dataset, which contains 71,868 photographs of apes from six species, annotated using 16 body landmarks. To test the dataset, the researchers trained an artificial intelligence network on separate monkey, human and ape datasets. The findings showed that the network is better at tracking apes when trained on ape images rather than those of monkeys or humans. It is also equally good at tracking apes as other monkey and human networks are at tracking their own species. This is contrary to optimistic expectations that monkey and human models could be generalized to apes. Training the network without images of one of the six ape species showed that it can still track the excluded species better than monkey and human models can. These experiments highlight the importance of species and family-specific datasets. OpenApePose is a valuable resource for researchers from various fields. It can aid tracking of animal behavior in the wild using large quantities of footage recorded by camera traps and drones. Artificial intelligence models trained on the OpenApePose dataset could also help scientists ­ such as neuroscientists ­ link movement with other types of data, including brain activity measurements, to gain deeper insights into behavior.

Comparative study of onlay versus sublay mesh repair in the management of ventral hernias.

Ventral hernias with large defects (≥ 2 cm) are managed with tension free mesh repair. The growing consensus that sublay (retrorectus) mesh repair is superior to onlay mesh repair due to fewer complications is based on literature dominated by retrospective studies from high and upper-middle income countries. There is thus a need of more prospective studies from various countries to resolve the controversy. The objective of this study was to compare the outcomes of onlay versus sublay mesh repair in the management of ventral hernias. Our single centre, prospective comparative study set in a low-middle income country comprised of 60 patients with a ventral hernia undergoing open surgical repair using either onlay technique (n = 30) or sublay technique (n = 30). Surgical site infections, seroma formation, recurrence were found in 3.33%, 6.67%, 0% patients in sublay repair group and in 16.67%, 20%, 6.67% patients in onlay repair group respectively. Mean duration of surgery, mean Visual Analogue Scale (VAS) score for chronic pain, mean duration of hospital stay were 46 min, 4.5, 8 days in onlay repair group and 61 min, 4.2, 6 days in sublay repair group respectively. Onlay repair group was associated with shorter duration of surgery. However, sublay repair was associated with lesser rates of surgical site infections, chronic pain and recurrence than onlay repair. Sublay mesh repair had better outcomes than onlay mesh repair for the management of ventral hernias, however superiority of any one technique could not be established.

Correlates of individual participation in boundary patrols by male chimpanzees.

Group territory defence poses a collective action problem: individuals can free-ride, benefiting without paying the costs. Individual heterogeneity has been proposed to solve such problems, as individuals high in reproductive success, rank, fighting ability or motivation may benefit from defending territories even if others free-ride. To test this hypothesis, we analysed 30 years of data from chimpanzees (Pan troglodytes) in the Kasekela community, Gombe National Park, Tanzania (1978-2007). We examined the extent to which individual participation in patrols varied according to correlates of reproductive success (mating rate, rank, age), fighting ability (hunting), motivation (scores from personality ratings), costs of defecting (the number of adult males in the community) and gregariousness (sighting frequency). By contrast to expectations from collective action theory, males participated in patrols at consistently high rates (mean ± s.d. = 74.5 ± 11.1% of patrols, n = 23 males). The best predictors of patrol participation were sighting frequency, age and hunting participation. Current and former alpha males did not participate at a higher rate than males that never achieved alpha status. These findings suggest that the temptation to free-ride is low, and that a mutualistic mechanism such as group augmentation may better explain individual participation in group territorial behaviour. This article is part of the theme issue 'Intergroup conflict across taxa'.

Prevalence of and factors associated with treatment modification at first cycle in older adults with advanced cancer receiving palliative treatment.

INTRODUCTION: Treatment toxicities are common in older adults with cancer and consequently, treatment modifications are sometimes considered. We evaluated the prevalence and factors associated with treatment modifications at the first cycle in older patients receiving palliative systemic treatment. METHODS: Patients (n = 369) from the GAP 70+ Trial (NCT02054741; PI: Mohile) usual care arm were included. Enrolled patients were aged 70+ with advanced cancer and ≥ 1 Geriatric Assessment (GA) domain impairment. Treatment modification was defined as any change from National Comprehensive Cancer Network guidelines or published clinical trials. Baseline variables included: 1) sociodemographic factors; 2) clinical variables; 3) GA domains; and 4) physician beliefs about life expectancy. Bivariate analyses and multivariable cluster-weighted generalized estimating equation model were conducted to assess the association of baseline variables with cycle 1 treatment modifications. RESULTS: Mean age was 77.2 years (range: 70-94); 62% had lung or gastrointestinal cancers, and 35% had treatment modifications at cycle 1. Increasing age by one year (odds ratio (OR) 1.1, 95% confidence interval [CI] 1.0-1.2), receipt of ≥second line of chemotherapy (OR 1.8, CI 1.1-3.0), functional impairment (OR 1.6, CI 1.1-2.3) and income ≤$50,000 (OR 1.7, CI 1.1-2.4) were independently associated with a higher likelihood of cycle 1 treatment modification. CONCLUSION: Treatment modifications occurred in 35% of older adults with advanced cancer at cycle 1. Increasing age, receipt of ≥second line of chemotherapy, functional impairment, and lower income were independently associated with treatment modifications. These findings emphasize the need for evidence-based regimens in older adults with cancer and GA impairments.

Loss of SWI/SNF Chromatin Remodeling Alters NRF2 Signaling in Non-Small Cell Lung Carcinoma.

The NF-E2-related factor 2 (referred to as NRF2) transcription factor binds antioxidant responsive elements within the promoters of cytoprotective genes to induce their expression. Next-generation sequencing studies in lung cancer have shown a significant number of activating mutations within the NRF2 signaling pathway. Mutations in components of the SWI/SNF chromatin-remodeling complex, a general regulator of transcription using either BRG1 or BRM as the catalytic subunit, also frequently occur in lung cancers. Importantly, low BRG1 expression levels in primary human NSCLC correlated with increased NRF2-target gene expression. Here, we show that loss of SWI/SNF complex function activated a subset of NRF2-mediated transcriptional targets. Using a series of isogenic NSCLC lines with reduced or depleted BRG1 and/or BRM expression, we observed significantly increased expression of the NRF2-target genes HMOX1 and GSTM4. In contrast, expression of the NRF2 target genes NQO1 and GCLM modestly increased following BRM reduction. Chromatin immunoprecipitation showed that BRG1 knockdown led to increased NRF2 binding at its respective ARE sites in the HMOX1 promoter but not in NQO1 and GCLM. Our data demonstrate that loss of BRG1 or BRM in lung cancer results in activation of the NRF2/KEAP1 pathway and HMOX1 expression. Therefore, we provide an additional molecular explanation for why patients harboring BRG1 or BRM mutations show poor prognoses. A better understanding of this mechanism may yield novel insights into the design of targeted treatment modalities. IMPLICATIONS: Our study identifies a novel mechanism for how mutations in the SMARCA4 gene may drive progression of human lung adenocarcinomas.