• Taking Control of Aggression: Perceptions of Aggression Suppress the Link Between Perceptions of Facial Masculinity and Attractiveness

      Geniole, Shawn N; McCormick, Cheryl M (SAGE Publishing, 2013)
      Women’s preferences for masculine-looking male faces are inconsistent across studies, with some studies finding a positive relationship between masculinity and attractiveness and others finding a negative relationship or no association. One possible reason for this inconsistency is that the perception of masculinity is also associated with perceptions of aggression, which may be viewed as particularly costly to women (aggressive individuals are more likely to experience injury or death). Based on the proposal that women’s preference for masculinity is in conflict with their aversion for aggression in male faces, we hypothesized that the bivariate associations between perceptions of masculinity and attractiveness would be weak or negative, but would be positive and significantly stronger after controlling statistically for perceptions of aggression. Across three studies involving three sets of faces (n = 25, 54, 24) and five sets of raters (n = 29, 30, 26, 16, 10), this hypothesis was supported with the average correlation between perceptions of masculinity and attractiveness (r = -.09) reversing in direction and substantially increasing in magnitude after perceptions of aggression were controlled statistically (r = .35). Perceived masculinity may thus involve both attractive and unattractive components, and women’s preferences for masculinity may involve weighing its relative costs and benefits.
    • Targeting inflammation to influence mood following spinal cord injury: a randomized clinical trial

      Allison, David; Ditor, David (Journal of Neuroinflammation, 2015)
      Background: The purpose of the present study was to examine the efficacy of targeting inflammation as a means of improving mood following spinal cord injury (SCI) and explore the potential mechanisms of action. Methods: The study was a randomized, parallel-group, controlled, clinical trial (NCT02099890) whereby 20 participants with varying levels and severities of SCI were randomized (3:2) to either the treatment group, consisting of a 12-week anti-inflammatory diet, or control group. Outcome measures were assessed at baseline, 1 and 3 months, and consisted of CES-D scores of depression, markers of inflammation as assessed by various pro- and anti-inflammatory cytokines and several amino acids related to depression. Results: A significant group × time interaction was found for CES-D (Center for Epidemiologic studies Depression Scale) score ( p = 0.01), the TRP/LNAA (tryptophan/large neutral amino acid) ratio ( p = 0.04), the composite score of pro-inflammatory cytokines ( p = 0.04), IL-1 β (interleukin-1 beta) ( p = 0.04), and IFN- γ (interferon gamma) ( p = 0.03). Pearson ’ s r correlation showed significance between the Δ IL-1 β and both the Δ CES-D score ( r = 0.740, p < 0.01) and the Δ KYN/TRP (kynurenine/tryptophan) ratio ( r = 0.536, p = 0.02). The Δ KYN/TRP ratio was also significantly correlated with the Δ CES-D score ( r = 0.586, p = 0.01). Mediation analysis showed that the relationship between the Δ KYN/TRP ratio and the Δ CES-D score was mediated by the Δ IL-1 β . Subgroup analysis showed that participants with high CES-D scores had significantly higher concentrations of IL-1 β , and all correlations were maintained or strengthened within this subgroup. Conclusions: Overall, the results demonstrated the effectiveness of targeting inflammation as a means of improving mood in SCI, with potential mechanisms relating to the reduction in IL-1 β and improvements in levels of neuroactive compounds related to the kynurenine pathway. Due to the limited sample size, results should be interpreted with caution; however, they are worthy of further examination due to the potential impact of inflammation on depression
    • Team Dynamics and Learning Opportunities in Social Science Research Teams

      McGinn, Michelle K.; Niemczyk, Ewelina K. (University of Alberta. Faculty of Education., 2020)
      Although the contemporary research environment encourages knowledge generation through research collaboration rather than individualized projects, limited scholarly attention has been devoted to the practice of collaboration within research teams. This paper presents a qualitative analysis of team dynamics and learning opportunities within four social science research teams. The findings reveal similarities and differences in leadership style and interaction approaches that affected how research was undertaken and the possibilities for team members to learn from each other. The snapshots provide models for other research teams that extend situated learning theories and the existing research base about collaboration, research teams, and research leadership.
    • Testing the validity of a continuous false belief task in 3- to 7-year-old children

      Mahy, Caitlin; Bernstein, Daniel M.; Gerrard, Lindsey D.; Atance, Christina M. (Elsevier, 2017)
      A continuous measure of false belief showed development in 3–7 year old children. False belief bias was related to Change of Location task performance. False belief bias was unrelated to measures of inhibition. The continuous measure of false belief shows convergent and discriminant validity. In two studies, we examined young children’s performance on the paper-and-pencil version of the Sandbox task, a continuous measure of false belief, and its relations with other false belief and inhibition tasks. In Study 1, 96 children aged 3 to 7years completed three false belief tasks (Sandbox, Unexpected Contents, and Appearance/Reality) and two inhibition tasks (Head–Shoulders–Knees–Toes and Grass/Snow). Results revealed that false belief bias—a measure of egocentrism—on the Sandbox task correlated with age but not with the Unexpected Contents or Appearance/Reality task or with measures of inhibition after controlling for age. In Study 2, 90 3- to 7-year-olds completed five false belief tasks (Sandbox, Unexpected Contents, Appearance/Reality, Change of Location, and a second-order false belief task), two inhibition tasks (Simon Says and Grass/Snow), and a receptive vocabulary task (Peabody Picture Vocabulary Test). Results showed that false belief bias on the Sandbox task correlated negatively with age and with the Change of Location task but not with the other false belief or inhibition tasks after controlling for age and receptive vocabulary. The Sandbox task shows promise as an age-sensitive measure of false belief performance during early childhood and shows convergent and discriminant validity.
    • That's my teacher! Children's ability to recognize personally familiar and unfamiliar faces improves with age

      Laurence, Sarah; Mondloch, Catherine J. (Elsevier Ltd, 2016-03)
      Highlights •Tested children’s ability to recognize faces across natural variation in appearance.•4- to 12-year-olds were asked to find all the images of an identity.•Performance was (nearly) perfect by 6years for familiar identities.•Performance improved across the entire age range for unfamiliar identities.•Findings have implications for models of the development of face perception.
    • Theorizing Community for Sport Management Research and Practice

      Rich, Kyle A.; Spaaij, Ramón; Misener, Laura (Frontiers Media SA, 2021-11-19)
      Community is a context for much research in sport, sport management, and sport policy, yet relatively few authors explicitly articulate the theoretical frameworks with which they interrogate the concept. In this paper, we draw from communitarian theory and politics in order to contribute to a robust discussion and conceptualization of community in and for sport management research and practice. We provide a synthesis of current sport management and related research in order to highlight contemporary theoretical and methodological approaches to studying community. We distinguish between community as a context, as an outcome, as a site for struggle or resistance, as well as a form of regulation or social control. We then advance a critical communitarian agenda and consider the practical implications and considerations for research and practice. This paper synthesizes current research and establishes a foundation upon which sport management scholars and practitioners might critically reflect on community and deliberatively articulate its implications in both future research and practice.
    • Thermal Imaging and Physiological Analysis of Cold-Climate Caribou-Skin Clothing

      Hill, Richard W.; Tattersall, Glenn J.; Campbell, Kevin L.; Reinfort, Breanne; Breit, Ana M.; Riewe, Rick R.; Humphries, Murray M. (Arctic Institute of North America, 2019-11-05)
      Protective clothing is essential for human existence in the Arctic, and caribou-skin clothing has played a pivotal role for millennia. Although people with northern experience often extol caribou-skin clothing, few scientific studies have investigated its properties. We used infrared thermal imaging in a pilot study to compare authentic caribou-skin clothing sewn by traditional Inuit seamstresses with two other types of cold-weather clothing: a standard-issue, Canadian army, winter uniform and an ensemble of modern retail clothing designed for extreme cold (a down anorak and snowmobile pants). To make the comparison, two subjects sequentially wore the three types of clothing—caribou skin, army uniform, and modern retail—in a still air, uniform thermal environment (where radiant temperatures of all environmental surfaces were equal to air temperature) at −21°C to −23°C (−6°F to −10°F). Thermal imaging quantifies the temperature of the outer surface of clothing, thereby providing key, functionally relevant information on the interface where clothing and environment meet. Under otherwise similar conditions, a low clothing surface temperature indicates superior clothing performance and a reduced rate of heat loss from the body to the environment. Caribou-skin clothing was similar to modern extreme-cold retail clothing: the whole-body composite surface temperature of our subjects wearing caribou-skin clothing was −22.1°C to −22.7°C, compared with −21.6°C in both subjects wearing the modern retail clothing. The army winter uniform (−18.9°C to −20.0°C) was inferior. These quantitative results were mirrored by the subjects’ subjective impressions. A particular advantage of thermal imaging is that it pinpoints locations in clothing where heat leaks occur. Although the two types of modern clothing exhibited heat leaks at zippered structures (even though fully closed), the caribou-skin clothing evaded such heat leaks by lacking such structures, because it is donned over the head. The integral hood characteristic of a caribou-skin parka was also superior in comparison to the detachable hood of the army uniform.
    • Thermoregulatory behavior and orientation preference in bearded dragons

      Tattersall, Glenn J; Black, Ian RG (Elsevier, 2017)
      Animals commit time and energy to achieve and maintain thermally optimality, defined as the range of temperatures which maintains physiological processes operating at, or near, maximum conditions (Dewitt, 1967; Huey and Slatkin, 1976). For ectotherms which depend on environmental heat absorption, behaviors that adjust the rate of body temperature (Tb) change are crucial to thermoregulation (Cowles and Bogert, 1944). Although thermoregulatory behaviors are known to present during early life (Blumberg et al., 2002; Lang, 1981; Stahlschmidt et al., 2015; Vollset et al., 2013; Zhao et al., 2013), how thermoregulatory behaviors change through ontogeny is not well stu- died. Shuttling and basking behaviors, which have a high impact on body temperature, are likely present from an animal's first exposure to a novel thermal environment, although these behaviors are also subject to change with experience. For example, shuttling behaviors show lower precision in bearded dragons that are naïve to an operant con- ditioning thermoregulatory paradigm compared to those with prior experience or when the locomotory costs of thermoregulation are in- creased (Cadena and Tattersall, 2009). Indeed, that lizards dedicate time to exploring and adjusting to a thermal gradient in the lab suggests that learning plays a role in behavioral thermoregulation, especially in novel environments (Cadena and Tattersall, 2009). Subtle thermo- regulatory responses might, therefore, also require time and may even need to be learned well after hatching. Unlike birds and mammals, squamates do not typically display parental care behaviors after their young hatch (Reynolds et al., 2002). After hatching, neonates meet their needs on their own, but not all behaviors are present during every phase of an animal's life (Dawkins, 1995; Khan et al., 2010). Innate behaviors are responses that prepare an animal for adaptive reactions to the world around them, and are gen- erally fully formed from the outset without the need for experience or learning; this is also referred to as inbuilt adaptiveness (Dawkins, 1995). Learned behaviors are responses that develop through the ac- cumulation of experience and the retention of information (Barnard, 2003). For the purposes of this work, innate thermoregulatory beha- viors are those present from the neonatal stage that do not generally require experience. Examples of both innate and learned responses can be found in voluntary, involuntary, and autonomic behaviors (Dawkins, 1995), and thus thermoregulatory behaviors can be expected to reflect both innate and learned responses. Aside from morphological and developmental differences, neonatal bearded dragons differ from their adult counterparts, especially with respect to social behaviors (Khan et al., 2010). Neonates are more prone The regulation of body temperature is a critical function for animals. Although reliant on ambient temperature as a heat source, reptiles, and especially lizards, make use of multiple voluntary and involuntary behaviors to thermoregulate, including postural changes in body orientation, either toward or away from solar sources of heat. This thermal orientation may also result from a thermoregulatory drive to maintain precise control over cranial temperatures or a rostrally-driven sensory bias. The purpose of this work was to examine thermal or- ientation behavior in adult and neonatal bearded dragons (Pogona vitticeps), to ascertain its prevalence across different life stages within a laboratory situation and its interaction with behavioral thermoregulation. Both adult and neonatal bearded dragons were placed in a thermal gradient and allowed to voluntarily select tem- peratures for up to 8 h to observe the presence and development of a thermoregulatory orientation preference. Both adult and neonatal dragons displayed a non-random orientation, preferring to face toward a heat source while achieving mean thermal preferences of ~ 33–34 °C. Specifically, adult dragons were more likely to face a heat source when at cooler ambient temperatures and less likely at warmer temperatures, suggesting that or- ientation behavior counter-balances local selected temperatures but contributes to their thermoregulatory re- sponse. Neonates were also more likely to select cooler temperatures when facing a heat source, but required more experience before this orientation behavior emerged. Combined, these results demonstrate the importance of orientation to behavioral thermoregulation in multiple life stages of bearded dragons.
    • Thermoregulatory windows in Darwin's finches

      Tattersall, Glenn J; Chaves, Jaime; Danner, Raymond M (Wiley, 2017-08-31)
      1. Darwin's finches have been the focus of intense study demonstrating how climatic fluctuations coupled with resource competition drive the evolution of a variety of bill sizes and shapes. The bill, as other peripheral surfaces, also plays an important role in thermoregulation in numerous bird species. The avian bill is vascularized, while limbs have specialized vasculature that facilitate heat loss or heat conservation (i.e. they are thermoregulatory windows). 2. The Galápagos Islands, home to Darwin's finches, have a hot and relatively dry climate for approximately half of the year, during which thermoregulatory windows (i.e. surfaces) could be important for thermoregulation and the linked challenge of water balance. 3. We hypothesized that Darwin's finch bills have evolved in part for their role in thermoregulation, possibly co-opted, following adaptation for other functions, such as foraging. We predicted that bills of Darwin's finches are effective thermoregulatory windows, and that species differences in bill morphology, along with physiology and behaviour, lead to differences in thermoregulatory function. 4. To test these hypotheses, we conducted a field study to assess heat exchange and microclimate use in three ground finch species and sympatric cactus finch (Geospiza spp.). We collected thermal images of free-living birds during a hot and dry season and recorded microclimate data for each observation. We used individual thermographic data to model the contribution of bills, legs and bodies to overall heat balance and compared surface temperatures to those from dead birds to test physiological control of heat loss from these surfaces. We derived and compared species-specific threshold environmental temperatures, which are indicative of a species’ thermally neutral temperature. 5. In all species, the bill surface was an effective heat dissipater during naturally occurring warm temperatures. As expected, we found that finches controlled surface temperatures through physiology and that young birds had higher surface temperatures than adults. Larger bills contributed proportionally more to overall heat loss than smaller bills. 6. We demonstrate here that related, sympatric species with different bill sizes exhibit different patterns in the use of these thermoregulatory structures, supporting a role for thermoregulation in the evolution and ecology of Darwin's finch morphology.
    • These pretzels are going to make me thirsty tomorrow: Differential development of hot and cool episodic foresight in early childhood?

      Mahy, Caitlin; Grass, Julia; Wagner, Sarah; Kliegel, Matthias (Wiley, 2014)
      The current study examined 3‐ and 7‐year‐olds' performance on two types of episodic foresight tasks: A task that required ‘cool’ reasoning processes about the use of objects in future situations and a task that required ‘hot’ processes to inhibit a salient current physiological state in order to reason accurately about a future state. Results revealed that 7‐year‐olds outperformed 3‐year‐olds on the episodic foresight task that involved cool processes, but did not show age differences in performance on the task that involved hot processes. In fact, both 3‐ and 7‐year‐olds performed equally poorly on the task that required predicting a future physiological state that was in conflict with their current state. Further, performance on the two tasks was unrelated. We discuss the results in terms of differing developmental trajectories for episodic foresight tasks that differentially rely on hot and cool processes and the universal difficulties humans have with predicting later outcomes that conflict with current motivational states.
    • Thinking about the future: Comparing children’s forced-choice versus “generative” responses in the “spoon test”

      Atance, Christina M.; Celebi, Seyda Nur; Mitchinson, Sarah; Mahy, Caitlin (Elsevier, 2019)
      Episodic future thinking has been assessed in children using the “spoon test”. In this test, children select an item that will be useful in the future. We adapted this test so that preschoolers had to verbally generate the item. For all age groups generating the correct item was more difficult than selecting it. Performance in the “generate” condition was related to category fluency. One of the most popular methods to assess children’s foresight is to present children with a problem (e.g., locked box with no key) in one room and then later, in another room, give them the opportunity to select the item (e.g., key) that will solve it. Whether or not children choose the correct item to bring back to the first room is the dependent measure of interest in this “spoon test.” Although children as young as 3 or 4 years typically succeed on this test, whether they would pass a more stringent version in which they must verbally generate (vs. select) the correct item in the absence of any cues is unknown. This is an important point given that humans must often make decisions about the future without being explicitly “prompted” by the future-oriented option. In Experiment 1, using an adapted version of the spoon test, we show that as the “generative” requirements of the task increase, 3-, 4-, and 5-year-olds’ (N = 99) performance significantly decreases. We replicate this effect in Experiment 2 (N = 48 3-, 4-, and 5-year-olds) and also provide preliminary evidence that the capacity to verbally generate the correct item in a spoon test may draw more heavily on children’s category fluency skills than does their capacity to select this item among a set of distracters. Our findings underscore the importance of examining more generative forms of future thought in young children.
    • To Jupyter and Beyond: Computational Notebooks in the Library

      Ribaric, Tim; Brett, Daniel (2020-01-29)
      Have you heard of Jupyter? Better yet, have you heard about how computational notebooks can be used to teach technologies and are part of the reproducible science movement? This session will show you the Juptyer platform and explain why you should know about it.
    • To repeat or not to repeat a course

      Armstrong, Michael J.; Biktimirov, Ernest N. (Taylor & Francis, 2013)
      The difficult transition from high school to university means that many students need to repeat (retake) one or more of their university courses. This paper examines the performance of students who were repeating first-year core courses in an undergraduate business program. It used data from university records for 116 students who took a total of 232 repeated courses across 6 subjects. The results show that the student’s original course grade and cumulative grade point average were positively associated with the new grade obtained in the repeated course. Conversely, the original course grade was negatively associated with the extent of improvement obtained by repeating.
    • Tortoises develop and overcome position biases in a reversal learning task

      Bridgeman, Justin; Tattersall, Glenn (Springer-Nature, 2019-02-01)
      The capability of animals to alter their behaviour in response to novel or familiar stimuli, or behavioural flexibility, is strongly associated with their ability to learn in novel environments. Reptiles are capable of learning complex tasks and offer a unique opportunity to study the relationship between visual proficiency and behavioural flexibility. The focus of this study was to investigate the behavioural flexibility of red-footed tortoises and their ability to perform reversal learning. Reversal learning involves first learning a particular discrimination task, after which the previously rewarded cue is reversed and then subjects perform the task with new reward contingencies. Red-footed tortoises were required to learn to recognise and approach visual cues within a Y-maze. Once subjects learned the visual discrimination, tortoises were required to successfully learn 4 reversals. Tortoises required significantly more trials to reach criterion (80% correct) in the first reversal, indicating the difficulty of unlearning the positive stimulus presented during training. Nevertheless, subsequent reversals required a similar number of sessions to the training stage, demonstrating that reversal learning improved up to a point. All subjects tested developed a position bias within the Y-maze that was absent prior to training, but most were able to exhibit reversal learning. Red-footed tortoises primarily adopted a win-stay choice strategy while learning the discrimination without much evidence for a lose-shift choice strategy, which may explain limits to their behavioural flexibility. However, improving performance across reversals while simultaneously overcoming a position bias provides insights into the cognitive abilities of tortoises.
    • Toughest job in the library

      Gordon, Ian D. (Emerald Publishing Limited, 2021)
      Purpose The purpose of this article attempts to portray the unique and complex role of library middle managers. This important and influential position can be a proving ground for new and old managers as libraries continue to evolve, adjust policies, introduce new services and meet the needs of their users. Circulation managers as influential middle managers are realistically depicted as busy, overwhelmed and isolated, but welcome the opportunity to provide leadership and enhance their professional development. Design/methodology/approach This viewpoint is solely based on the author's varied experiences and personal reflections as a circulation department head providing leadership alongside colleagues in a busy academic library. Findings Department heads as managers of circulation departments are pivotal positions in every library. Circulation heads performing as middle managers are responsible for a full range of administrative, managerial and organizational services. Circulation heads are well positioned as change agents simultaneously directing frontline staff members, policies and services while providing valuable insight to library administration. Yet, circulation managers experiencing constantly evolving responsibilities, are too often found to be caught in the middle negotiating inconsistencies. Successful circulation managers require an eclectic mix of essential skills initiating and deploying change, defining success, dealing with people, actively participating in professional development and providing leadership. Research limitations/implications The study and research of library middle managers in public and academic libraries is practically nonexistent. As libraries increasingly create, adjust and reinvent library services, spaces and visions due to increasing digitization, in response to emerging online environments and new service models – middle managers and circulation librarians are excellent and proven pivots to negotiate and successfully implement this change. Practical implications As a crafted article written by a former head of a circulation department every staff member, student and librarian serving in access/borrowing/circulation departments should consult this article as required reading.Social implications The voices of library middle managers are too often muted, not valued and rarely celebrated. This viewpoint article written in a conversational voice depicts circulation librarians as middle managers that bring value to all libraries and should be heard. Originality/value This paper depicts the opportunities and challenges faced by, as well as the skills and competencies required by librarians serving as circulation departments heads.
    • Transfer-Learning-Based Approach for the Diagnosis of Lung Diseases from Chest X-ray Images

      Fan, Rong; Bu, Shengrong (MDPI, 2022)
      Using chest X-ray images is one of the least expensive and easiest ways to diagnose patients who suffer from lung diseases such as pneumonia and bronchitis. Inspired by existing work, a deep learning model is proposed to classify chest X-ray images into 14 lung-related pathological conditions. However, small datasets are not sufficient to train the deep learning model. Two methods were used to tackle this: (1) transfer learning based on two pretrained neural networks, DenseNet and ResNet, was employed; (2) data were preprocessed, including checking data leakage, handling class imbalance, and performing data augmentation, before feeding the neural network. The proposed model was evaluated according to the classification accuracy and receiver operating characteristic (ROC) curves, as well as visualized by class activation maps. DenseNet121 and ResNet50 were used in the simulations, and the results showed that the model trained by DenseNet121 had better accuracy than that trained by ResNet50.
    • The Transition Online: A Mixed-Methods Study of the Impact of COVID-19 on Students with Disabilities in Higher Education

      Mullins, Laura E; Mitchell, Jennifer (Sciedu Press, 2021-09-05)
      Following the World Health Organization’s announcement of the global pandemic because of the Coronavirus Disease 2019, most Canadian universities transitioned to offering their courses exclusively online. One group affected by this transition was students with disabilities. Previous research has shown that the university experience for students with disabilities differs from those of their non-disabled peers. However, their unique needs are often not taken into consideration. As a result, students can become marginalized and alienated from the online classroom. In partnership with Student Accessibility Services, this research revealed the impact of the transition to online learning because of the pandemic for university students with disabilities. Students registered with Student Accessibility Services completed a survey about the effects of online learning during a pandemic on the students’ lives, education, and instructional and accommodation. It was clear from the results that online education during COVID-19 affected all aspects of the students’ lives, particularly to their mental health. This research provided a much-needed opportunity for students with disabilities to share the factors influencing their educational experience and identified recommendations instructors should consider when developing online courses to increase accessibility and improve engagement.
    • Transitions in Executive Function: Insights From Developmental Parallels Between Prospective Memory and Cognitive Flexibility

      Mahy, Caitlin; Munakata, Yoko (Wiley, 2015)
      As children develop, they need to remember to carry out their intentions and overcome habits to switch flexibly to new ways of behaving. Developments in these domains—prospective memory and cognitive flexibility—are essential for children to function and predict important outcomes. Prospective memory and cognitive flexibility are similar in the psychological processes proposed to support them (particularly executive functions), in how they are measured, and in the behavioral transitions observed (e.g., dissociations between actions and intentions, and nonlinear developmental trajectories). In this article, we highlight how such parallels can inform debates about the specific executive functions and types of developments that support prospective memory, cognitive flexibility, and related future‐oriented abilities, and can deepen understanding of executive function development more generally.
    • Transposable Elements Are a Significant Contributor to Tandem Repeats in the Human Genome

      Liang, Ping; Ahmed, Musaddeque (Hindawi Publishing Corporation, 2012-04-11)
      Sequence repeats are an important phenomenon in the human genome, playing important roles in genomic alteration often with phenotypic consequences. The two major types of repeat elements in the human genome are tandem repeats (TRs) including microsatellites, minisatellites, and satellites and transposable elements (TEs). So far, very little has been known about the relationship between these two types of repeats. In this study, we identified TRs that are derived from TEs either based on sequence similarity or overlapping genomic positions. We then analyzed the distribution of these TRs among TE families/subfamilies. Our study shows that at least 7,276 TRs or 23% of all minisatellites/satellites is derived from TEs, contributing ∼0.32% of the human genome. TRs seem to be generated more likely from younger/more active TEs, and once initiated they are expanded with time via local duplication of the repeat units. The currently postulated mechanisms for origin of TRs can explain only 6% of all TE-derived TRs, indicating the presence of one or more yet to be identified mechanisms for the initiation of such repeats. Our result suggests that TEs are contributing to genome expansion and alteration not only by transposition but also by generating tandem repeats.
    • Trematode Parasite Infection Affects Temperature Selection in Aquatic Host Snails

      Wang, Susan YS; Tattersall, Glenn Jeffery; Koprivnikar, Janet (University of Chicago Press, 2019-01)
      Animals infected by parasites or pathogens can exhibit altered behaviors that may reduce the costs of infection to the host or represent manipulations that benefit the parasite. Given that temperature affects many critical physiological processes, changes in thermoregulatory behaviors are an important consideration for infected hosts, especially ectotherms. Here we examined the temperature choices of freshwater snails (Helisoma trivolvis) that were or were not infected by a trematode (flatworm) parasite (Echinostoma trivolvis). Active snails that explored the experimental temperature gradient differed in their thermal preference based on their infection status, as parasitized snails chose to position themselves at a significantly higher temperature (mean: 25.4°C) compared to those that were uninfected (mean: 23.3°C). Given that snails rarely eliminate established trematode infections, we suggest that this altered thermal preference shown by infected hosts likely benefits the parasite by increasing the odds of successful transmission, either through enhanced production and emergence of infectious stages or by increasing spatial overlap with the next hosts of the complex life cycle. Further studies that employ experimental infections to examine temperature selection at different time points will be needed to understand the extent of altered host thermal preferences, as well as the possible benefits to both host and parasite.