Reciprocal Associations Between Science Efficacy, STEM Identity and Scientist Career Interest Among Adolescent Girls within the Context of Informal Science Learning.

Limited research has explored the longitudinal pathway to youth career interests via identity and efficacy together. This study examined the longitudinal associations between science efficacy, STEM (science, technology, engineering and math) identity, and scientist career interest among girls who are historically considered as an underrepresented group among scientists. The sample included 308 girls (M age = 15.22, SD age = 1.66; 42.8% White) from six STEM youth programs, each at a different informal science learning site within the U.K. and the U.S. Longitudinal structural equation modelling demonstrated that science efficacy consistently predicted STEM identity and scientist career interest, and similarly, STEM identity consistently predicted science efficacy over a two-year period. Scientist career interest at 12 months predicted science efficacy at 24 months. The coefficients of efficacy predicting STEM identity and scientist career interest were significantly larger compared to STEM identity and scientist career interest in predicting science efficacy from 12 months to 24 months. Further mediation analysis supported a significant pathway from STEM identity at 3 months to scientist career interest at 24 months via 12-month science efficacy. The findings highlight that science efficacy and STEM identity for girls relate to their scientist career interest and these longitudinal associations are reciprocal. This study suggests that science efficacy and STEM identity mutually influence each other, and enhancing science efficacy and STEM identity is key to promoting adolescents' interest in being a scientist.

Developmental Trajectories of Adolescents' Math Motivation: The Role of Mindset and Perceptions of Informal STEM Learning Site Inclusivity.

Motivation is a key factor in engagement, achievement, and career choices in science, technology, engineering, and mathematics (STEM). While existing research has focused on student motivation toward math in formal school programs, new work is needed that focuses on motivation for those involved in informal STEM programs. Specifically, the role of math mindset and perceived inclusivity of informal STEM sites (to those of varying gender and ethnic backgrounds) on longitudinal trajectories of adolescents' math motivation has not been explored. This study investigates longitudinal changes in math expectancy, interest, and utility values and the effects of math fixed mindset, math growth mindset, and perceptions of the inclusivity of informal STEM learning sites on these changes for adolescents participating in STEM programs at these informal sites in the United Kingdom and the United States (n = 249, MT1age = 15.2, SD = 1.59). Three latent growth curve models were tested. The data suggest that math expectancy, interest, and utility values declined over three years. Growth mindset positively predicted changes in utility, while fixed mindset negatively predicted changes in utility. Inclusivity positively influenced the initial levels of utility. Girls reported lower initial expectancy than boys. Age influenced both the initial levels and rate of change for expectancy. Older adolescents had lower levels of expectancy compared to their younger counterparts; however, they had a less steep decline in expectancy over three years. These findings suggest that designing inclusive learning environments and promoting growth mindset may encourage math motivation.

Promoting Diverse Youth's Career Development through Informal Science Learning: The Role of Inclusivity and Belonging.

Little research has examined the associations between perceived inclusivity within informal science learning sites, youth program belonging and perceptions of program career preparation. This study explored relations between these factors at three timepoints (T1 = start of program, T2 = 3 months and T3 = 12 months after start). Participants were a diverse sample of 209 adolescents participating in STEM youth programs within informal science learning sites situated in the United States and United Kingdom (70% females: M age = 15.27, SD age = 1.60), with 53.1% British and 64.1% non-White. Path analysis revealed that only perceptions of inclusivity for own social identity group (i.e., gender, ethnicity) at T1 were associated with T2 STEM youth program belonging. There was a significant indirect effect of T1 perceptions of inclusivity for one's own social identity groups on T3 perceptions of program career preparation via T2 program belonging. This study highlights that, over time, perceptions of inclusivity around youth's own social identity groups (i.e., gender and ethnicity/culture) are related to a sense of youth program belonging, which in turn is later associated with perceptions of program career preparation.

Interest, Mindsets and Engagement: Longitudinal Relations in Science Orientations for Adolescents in Informal Science Programs.

Little is known about the factors that influence engagement for adolescents participating in informal youth science programs. This study examined longitudinal reciprocal associations between adolescents' science engagement, interest, and growth mindset. Participants were adolescents (Mage = 15.06, SD = 1.82 years, 66.8% female) from the UK (n = 168) and the US (n = 299). A cross lagged path analysis indicated that participants' science growth mindset at baseline was positively related to interest, and engagement at year 1, and science interest at year 1 was positively related to growth mindset at year 2. Additionally, girls had lower science growth mindsets than boys. This evidence suggests that informal programs may encourage positive STEM trajectories by fostering engagement, growth mindset and interest.

Preparing the Next Generation for STEM: Adolescent Profiles Encompassing Math and Science Motivation and Interpersonal Skills and Their Associations With Identity and Belonging.

Science, technology, engineering, and math (STEM) workers need both motivation and interpersonal skills in STEM disciplines. The aims of the study were to identify clusters of adolescents who vary in math and science motivation and interpersonal skills and to explore what factors are related to membership in a high math and science motivation and interpersonal skills cluster. Participants included 467 adolescents (312 female; Mage = 15.12 to SD = 1.71 year) recruited from out-of-school STEM programs in the US and UK. Findings from latent class analyses revealed four clusters, including a "High Math and Science Motivation and Interpersonal Skills" group, as well as groups that exhibited lower levels of either motivation or interpersonal skills. STEM program belonging, and STEM identity are related to membership in the high motivation and skills cluster. Findings provide insight into factors that may encourage motivation and interpersonal skills in adolescents, preparing them for STEM workforce entry.

Evolution of facial muscle anatomy in dogs.

Domestication shaped wolves into dogs and transformed both their behavior and their anatomy. Here we show that, in only 33,000 y, domestication transformed the facial muscle anatomy of dogs specifically for facial communication with humans. Based on dissections of dog and wolf heads, we show that the levator anguli oculi medialis, a muscle responsible for raising the inner eyebrow intensely, is uniformly present in dogs but not in wolves. Behavioral data, collected from dogs and wolves, show that dogs produce the eyebrow movement significantly more often and with higher intensity than wolves do, with highest-intensity movements produced exclusively by dogs. Interestingly, this movement increases paedomorphism and resembles an expression that humans produce when sad, so its production in dogs may trigger a nurturing response in humans. We hypothesize that dogs with expressive eyebrows had a selection advantage and that "puppy dog eyes" are the result of selection based on humans' preferences.

Myological variation in the forearm anatomy of Callitrichidae and Lemuridae.

The anatomy of the primate forearm is frequently investigated in terms of locomotor mode, substrate use, and manual dexterity. Such studies typically rely upon broad, interspecific samples for which one or two representative taxa are used to characterize the anatomy of their genus or family. To interpret variation between distantly related taxa, however, it is necessary to contextualize these differences by quantifying variation at lower hierarchical levels, that is, more fine-grained representation within specific genera or families. In this study, we present a focused evaluation of the variation in muscle organization, integration, and architecture within two speciose primate families: the Callitrichidae and Lemuridae. We demonstrate that, within each lineage, several muscle functional groups exhibit substantial variation in muscle organization. Most notably, the digital extensors appear highly variable (particularly among callitrichids), with many unique configurations represented. In terms of architectural variables, both families are more conservative, with the exception of the genus Callimico-for which an increase is observed in forearm muscle mass and strength. We suggest this reflects the increased use of vertical climbing and trunk-to-trunk leaping within this genus relative to the more typically fine-branch substrate use of the other callitrichids. Overall, these data emphasize the underappreciated variation in forearm myology and suggest that overly generalized typification of a taxon's anatomy may conceal significant intraspecific and intrageneric variation therein. Thus, considerations of adaptation within the forearm musculature should endeavor to consider the full range of anatomical variation when making comparisons between multiple taxa within an evolutionary context.

The Relations and Role of Social Competencies and Belonging with Math and Science Interest and Efficacy for Adolescents in Informal STEM Programs.

Adolescence represents a developmental period of waning academic motivation, particularly in STEM domains. To combat this, better understanding the factors that might foster STEM motivation and interest is of importance. Social factors like social competencies and feelings of belonging become increasingly important in adolescence. The current study investigated structural relations between social competencies, feelings of belonging to an informal STEM learning program, math and science efficacy and interest in a sample of 268 adolescents (Mage = 15.25; 66.8% girls; 42.5% White British or European American, 25.7% South Asian British or Asian American, 15.7% Afro-Caribbean Black British or African American 5.6% Bi-racial, and 3.0% other). Adolescents were recruited from six different informal learning sites (e.g., science museums, zoos, or aquariums) in the United States (n = 147) and the United Kingdom (n = 121). The results revealed positive relations between social competencies and belonging, and between belonging and math and science efficacy and interest. Further, the results also indicated a positive indirect effect of social competencies on efficacy and interest, via belonging. These findings have implications for guiding informal STEM programming in ways that can enhance STEM motivation and interest.

A primate with a Panda's thumb: The anatomy of the pseudothumb of Daubentonia madagascariensis.

OBJECTIVES: Accessory digits have evolved independently within several mammalian lineages. Most notable among these is the pseudothumb of the giant panda, which has long been considered one of the most extraordinary examples of contingent evolution. To date, no primate has been documented to possess such an adaptation. Here, we investigate the presence of this structure within the aye-aye (Daubentonia madagascariensis), a species renowned for several other specialized morphological adaptations in the hand, including a morphologically unique third digit. MATERIALS AND METHODS: We combine physical dissection techniques with digital imaging processes across a sample of seven individuals (six adults and one immature individual) to describe and visualize the anatomy of the wrist and hand within the aye-aye. RESULTS: A distinct pseudothumb, which consists of both a bony component (an expanded radial sesamoid) and a dense cartilaginous extension (the "prepollex") was observed in all specimens. We demonstrate that this pseudodigit receives muscular attachments from three muscles, which collectively have the potential to enable abduction, adduction, and opposition. Finally, we demonstrate that the pseudothumb possesses its own distinct pad within the palm, complete with independent dermatoglyphs. DISCUSSION: Pseudothumbs have been suggested to improve palmar dexterity in taxa with overly -generalized first digits (e.g., pandas) and to widen the hand for digging (e.g., some fossorial moles), but the aye-aye's pseudothumb represents what we believe is a heretofore unrecognized third functional role: its accessory digit compensates for overspecialization of its fingers for non-gripping functions (in this case, the aye-aye's unique "tap foraging" practices).

Brief communication: Maximum ingested bite size in captive western lowland gorillas (Gorilla gorilla gorilla).

OBJECTIVES: Previously, we found that maximum ingested bite size (Vb ), the largest piece of food an animal can consume without biting it into smaller pieces first, isometrically scales relative to body size in strepsirrhines and with negative allometry in anthropoids. In the current study, we rectify the omission of great apes from the earlier sample to now characterize the Vb of the entire size-range of the order. MATERIALS AND METHODS: Five gorillas (Gorilla gorilla gorilla-G. g. gorilla) were studied to ascertain Vb in relation to the mechanical properties of five foods. RESULTS: Gorilla Vb ranged from 166.38 cm3 (for the least obdurate food: watermelon) to 8 cm3 (for the most obdurate food: turnip), with an average Vb of 33.50 cm3 across all food types. CONCLUSIONS: When these data were compared to those from our previous studies, we found that gorillas consumed relatively slightly smaller volumes of food compared to the trend found across primates. However, because the more frugivorous gorillas consumed relatively larger pieces of food than the large folivorous monkeys previously studied, including the gorilla data increased the slope of the linear regression between body mass and Vb in anthropoids. Thus, the addition of the largest living primate brings the anthropoid Vb trend closer to the Vb trend of the order. Notwithstanding, there is still negative allometry in anthropoid Vb , in contrast with the isometry in strepsirrhine Vb . Future research should include species with body masses between the smaller anthropoids and gorillas by studying the Vb of large papionids and the other great apes.

The gaits of marsupials and the evolution of diagonal-sequence walking in primates.

OBJECTIVES: Documenting the variety of quadrupedal walking gaits in a variety of marsupials (arboreal vs. terrestrial, with and without grasping hind feet), to aid in developing and refining a general theory of gait evolution in primates. MATERIALS AND METHODS: Video records of koalas, ringtail possums, tree kangaroos, sugar gliders, squirrel gliders, wombats, numbats, quolls, a thylacine, and an opossum walking on a variety of substrates were made and analyzed to derive duty factors and diagonalities for symmetrical walking gaits. The resulting distributions of data points were compared with published data and theories. RESULTS: Terrestrial marsupials' gaits overwhelmingly plot slightly below the theoretical "horse line" (Cartmill et al., Zoological Journal of the Linnean Society. 2002;136:401-420) typical of terrestrial mammals; arboreal marsupials' gaits overwhelmingly plot more decisively above it. Both distributions are roughly parallel to the horse line, but arboreal animals exhibit increased diagonality, so that their higher-speed walking gaits overlap with those of typical primates on the Hildebrand diagram of diagonality against duty factor. CONCLUSIONS: Quadrupeds avoid gaits lying exactly on the (theoretically optimum) horse line, to avoid fore/hind limb interference ("forging"). This can be accomplished by either a slight reduction in diagonality ("downshifting") or a more decisive increase ("upshifting"). Tree-dwellers adopt the second option to eliminate unilateral bipods of support from the gait cycle. The upshifted horse line represents an early phase in the evolution of primate-like diagonal-sequence gaits.

STEM gender stereotypes from early childhood through adolescence at informal science centers.

Stereotypes about science, technology, engineering and mathematics (STEM) are associated with reduced STEM engagement amongst girls and women. The present study examined these stereotypes from early childhood through adolescence within informal science learning sites (ISLS; science museums, zoos, aquariums). Further, the study explored whether interactions with male or female educators influenced STEM stereotypes. Participants (n = 997, female = 572) were ISLS visitors in the UK and USA who either interacted with an educator, or no educator. With age participants were more likely to report that "both boys and girls" are "usually", "should" be, and "can" be good at STEM. Independent of age, male participants reported that their own gender group "should" be good at STEM. Educator interactions did not influence stereotype responses. These results highlight early childhood as a key developmental window in which to challenge ideas about who can and should be proficient in STEM.

A Novel Method for Assessing Enamel Thickness Distribution in the Anterior Dentition as a Signal for Gouging and Other Extractive Foraging Behaviors in Gummivorous Mammals.

Gummivory poses unique challenges to the dentition as gum acquisition may often require that the anterior teeth be adapted to retain a sharp edge and to resist loading because they sometimes must penetrate a highly obdurate substrate during gum extraction by means of gouging or scraping. It has been observed previously that the enamel on the labial surface of the teeth used for extraction is thicker relative to that on the lingual surface in taxa that extract gums, while enamel is more evenly distributed in the anterior teeth of taxa that do not regularly engage in extractive behaviors. This study presents a quantitative methodology for measuring the distribution of labial versus lingual enamel thickness among primate and marsupial taxa in the context of gummivory. Computed microtomography scans of 15 specimens representing 14 taxa were analyzed. Ten measurements were taken at 20% intervals starting from the base of the crown of the extractive tooth to the tip of the cutting edge across the lingual and labial enamel. A method for including worn or broken teeth is also presented. Mann-Whitney U tests, canonical variates analysis, and between-group principal components analysis were used to examine variation in enamel thickness across taxa. Our results suggest that the differential distribution of enamel thickness in the anterior dentition can serve as a signal for gouging behavior; this methodology distinguishes between gougers, scrapers, and nonextractive gummivores. Gouging taxa are characterized by significantly thicker labial enamel relative to the lingual enamel, particularly towards the crown tip. Examination of enamel thickness patterning in these taxa permits a better understanding of the adaptations for the extraction of gums in extant taxa and offers the potential to test hypotheses concerning the dietary adaptations of fossil taxa.

Learning hand in hand: Engaging in research-practice partnerships to advance developmental science.

Developmental science research often involves research questions developed by academic teams, which are tested within community or educational settings. In this piece, we outline the importance of research-practice partnerships, which involve both research and practice-based partners collaborating at each stage of the research process. We articulate challenges and benefits of these partnerships for developmental science research, identify relevant research frameworks that may inform these partnerships, and provide an example of an ongoing research-practice partnership.

Extraordinary grip strength and specialized myology in the hyper-derived hand of Perodicticus potto?

Previous behavioral reports of the African lorisid, Perodicticus potto, have speculated that these animals have an extraordinary grip strength. This ability is hypothesized to be facilitated by a range of anatomical features within the forelimb, ranging from the presence of a retia mirabilia in its wrist to the hyper-abduction of its pollex. Despite numerous behavioral reports, however, this claim of extraordinary grip strength has not been empirically substantiated. This study quantifies the physiological cross-sectional area of the digital flexor muscles within P. potto. These data are compared with a broad primate sample, including several similarly sized strepsirrhines. Contrary to expectation, we found that P. potto actually has relatively below-average digital flexor PCSA. However, we identified other myological characteristics in the upper limb of P. potto that were unexpected, including the largest brachioradialis muscle (an elbow flexor) among our primate sample, and - despite P. potto having only a vestigial second digit - an independent digital extensor indicis that is absent in almost a quarter of our primate sample.

A Role for Human Skin Mast Cells in Dengue Virus Infection and Systemic Spread.

Dengue virus (DENV) is a mosquito-borne flavivirus that causes serious global human disease and mortality. Skin immune cells are an important component of initial DENV infection and systemic spread. Here, we show that mast cells are a target of DENV in human skin and that DENV infection of skin mast cells induces degranulation and alters cytokine and growth factor expression profiles. Importantly, to our knowledge, we also demonstrate for the first time that DENV localizes within secretory granules in infected skin mast cells. In addition, DENV within extracellular granules was infectious in vitro and in vivo, trafficking through lymph to draining lymph nodes in mice. We demonstrate an important role for human skin mast cells in DENV infection and identify a novel mechanism for systemic spread of DENV infection from the initial peripheral mosquito injection site.

The ligamentum teres femoris in orangutans.

OBJECTIVES: It is widely viewed that orangutans lack a ligamentum teres femoris (LTF) inserting on the femoral head because orangutans lack a distinct fovea capitis. Orangutans employ acrobatic quadrumanous clambering that requires a high level of hip joint mobility, and the absence of an LTF is believed to be an adaptation to increase hip mobility. However, there are conflicting reports in the literature about whether there may be a different LTF configuration in orangutans, perhaps with a ligament inserting on the femoral neck instead. Here we perform a dissection-based study of orangutan hip joints, assess the soft tissue and hard tissue correlates of the orangutan LTF, and histologically examination the LTF to evaluate whether it is homologous to that found in other hominoids. MATERIALS AND METHODS: The hip joints from six orangutans were dissected. In the two orangutans with an LTF passing to the femoral head, the LTF was assessed histologically. Skeletonized femora (n=56) in osteological repositories were examined for evidence of a foveal pit. RESULTS: We observed an LTF in two of the three infant orangutans but not in the sub-adult or adult specimens. Histological examination of the infant LTF shows a distinct artery coursing through the LTF to the head of the femur. One percent of orangutan femora present with a foveal scar, but no pit, on the femoral head. DISCUSSION: Despite being absent in adults, the LTF is present in at least some orangutans during infancy. We suggest that the LTF maintains a role in blood supply to the femoral head early in life. Because the LTF can limit hip mobility, this may explain why the LTF may be lost as an orangutan ages and gains locomotor independence. These findings enhance our understanding of orangutan hip morphology and underscore the need for future soft tissue investigations.

A relevant in vitro human model for the study of Zika virus antibody-dependent enhancement.

Zika virus (ZIKV) is a mosquito-borne flavivirus that has recently been responsible for a serious outbreak of disease in South and Central America. Infection with ZIKV has been associated with severe neurological symptoms and the development of microcephaly in unborn fetuses. Many of the regions involved in the current outbreak are known to be endemic for another flavivirus, dengue virus (DENV), which indicates that a large percentage of the population may have pre-existing DENV immunity. Thus, it is vital to investigate what impact pre-existing DENV immunity has on ZIKV infection. Here, we use primary human myeloid cells as a model for ZIKV enhancement in the presence of DENV antibodies. We show that sera containing DENV antibodies from individuals living in a DENV-endemic area are able to enhance ZIKV infection in a human macrophage-derived cell line and primary human macrophages. We also demonstrate altered pro-inflammatory cytokine production in macrophages with enhanced ZIKV infection. Our study indicates an important role for pre-existing DENV immunity on ZIKV infection in primary human immune cells and establishes a relevant in vitro model to study ZIKV antibody-dependent enhancement.

Characterizing felid tooth marking and gross bone damage patterns using GIS image analysis: an experimental feeding study with large felids.

In recent years there has been much disagreement over the nature of carnivore involvement in Early Pleistocene zooarchaeological assemblages. This partially reflects the lack of reliable ways to identify the taphonomic signatures of different large carnivore taxa. It is often unclear which carnivore taxon or taxa may have played a role in forming or modifying faunal assemblages found associated with stone tools, and this lack of clarity impacts reconstructions of hominin behavior. The mode, frequency and nutritional yield of carcasses acquired by hominins, and the extent to which hominin foraging impinged on or was constrained by the guild of large predators are topics of great importance. This paper characterizes the taphonomic signature of large felids using a Geographic Information Systems (GIS) image analysis method to study tooth marking and gross bone damage on neotaphonomic experiments carried out with tigers (Panthera tigris) and African lions (Panthera leo) at the Carolina Tiger Rescue (Pittsboro, North Carolina). This sample of over 400 bones significantly increases the size of current neotaphonomic samples modeling felid feeding traces, more than doubling the number of felid-modified specimens described in the literature. We identify a typical pattern of bone damage resulting from large felid carcass modification, which can be distinguished from bone damage patterns produced by hyaenids and canids. In summary, this pattern consists of tooth marking largely restricted to limb bone ends and minimal bone fragmentation. The frequency of tooth marking imparted by large felids in this study is lower than that produced by hyaenids, while canid tooth mark frequencies fall between the two. Investigation of the FLK Zinj assemblage from Olduvai Gorge, Tanzania, has documented several specimens with surface damage similar to our neotaphonomic sample. This may signal early access to carcasses through 'power scavenging' by hominins.