The Simons Observatory: Cryogenic half wave plate rotation mechanism for the small aperture telescopes

We present the requirements, design, and evaluation of the cryogenic continuously rotating half-wave plate (CHWP) for the Simons Observatory (SO). SO is a cosmic microwave background polarization experiment at Parque Astronómico de Atacama in northern Chile that covers a wide range of angular scales using both small (⌀0.42 m) and large (⌀6 m) aperture telescopes. In particular, the small aperture telescopes (SATs) focus on large angular scales for primordial B-mode polarization. To this end, the SATs employ a CHWP to modulate the polarization of the incident light at 8 Hz, suppressing atmospheric 1/f noise and mitigating systematic uncertainties that would otherwise arise due to the differential response of detectors sensitive to orthogonal polarizations. The CHWP consists of a 505 mm diameter achromatic sapphire HWP and a cryogenic rotation mechanism, both of which are cooled down to ∼50 K to reduce detector thermal loading. Under normal operation, the HWP is suspended by a superconducting magnetic bearing and rotates with a constant 2 Hz frequency, controlled by an electromagnetic synchronous motor. We find that the number of superconductors and the number of magnets that make up the superconducting magnetic bearing are important design parameters, especially for the rotation mechanism's vibration performance. The rotation angle is detected through an angular encoder with a noise level of 0.07 μrad s. During a cooldown process, the rotor is held in place by a grip-and-release mechanism that serves as both an alignment device and a thermal path. In this paper, we provide an overview of the SO SAT CHWP: its requirements, hardware design, and laboratory performance.

A scalable cryogenic LED module for selectively illuminating kinetic inductance detector arrays

We present the design and measured performance of a light emitting diode (LED) module for spatially mapping kinetic inductance detector (KID) arrays in the laboratory. Our novel approach uses a multiplexing scheme that only requires seven wires to control 480 red LEDs, and the number of LEDs can be scaled up without adding any additional wires. This multiplexing approach relies on active surface mount components that can operate at cryogenic temperatures down to 10 K. Cryogenic tests in liquid nitrogen and inside our cryostat demonstrate that the multiplexer circuit works at 77 and 10 K, respectively. The LED module presented here is tailored for our millimeter-wave detector modules, but the approach could be adapted for use with other KID-based detector systems.

Beliefs affecting concussion reporting among military cadets: advanced observations through machine learning

BACKGROUND

Untreated concussions are an important health concern. The number of concussions sustained each year is difficult to pinpoint due to diverse reporting routes and many people not reporting. A growing body of literature investigates the motivations for concussion under-reporting, proposing ties with knowledge of concussion outcomes and concussion culture. The present work employs machine learning to identify trends in knowledge and willingness to self-report concussions.

METHODS

2,204 cadets completed a survey addressing athletic and pilot status, concussion symptoms and outcome beliefs, ethical beliefs, demographics, and reporting willingness.

RESULTS

Clustering and non-negative matrix analysis identified connections to self-report willingness within: knowledge of symptoms, ethical beliefs, reporting requirements, and belief of long-term concussion outcomes. Support vector machine classification of cadet reporting likelihood reveals symptom and outcome knowledge may be inversely related to reporting among those rating ethics considerations as low, while heightened ethics may predict higher reporting likeliness overall.

CONCLUSIONS

Machine-learning analysis bolsters prior theories on the importance of concussion culture in reporting and indicate more symptom knowledge may decrease willingness to report. Uniquely, our analysis indicated importance of ethical behavior may be associated with general concussion reporting willingness, inviting further consideration from healthcare practitioners seeking increased reporting.

Concussion reporting intentions for incoming military athletes and cadets

Cultures of concussion reporting exist outside athletics; however, athlete-only studies dominate the literature. Comparing athletes and similar high-risk populations broadens our understanding of concussion reporting acculturation. We aimed to (1) describe and compare concussion self-report willingness as measured by anticipated concussion reporting (ACR), perceived costs, perceived rewards, brain health knowledge, and correct symptom identification for incoming cadets at the United States Air Force Academy (USAFA) (n = 1,136; female = 276, 24.43%) and (2) determine whether those variables predict ACR. Univariate analyses were performed to compare intercollegiate status, sex, and parental income for perceived costs and rewards, and brain health knowledge (α = 0.05) and multinomial logistic regressions to determine if those variables predicted ACR. A $40,000 parental increase in income resulted in one additional symptom identified (β = 0.80, p = 0.026). Athletes demonstrated greater brain health knowledge by nearly one symptom correctly identified (β = 0.98, p = 0.002); non-athletes reported significantly greater ACR (β = 5.92; p < 0.001). Our model accounted for 37% of the variance in ACR (χ2 = 393.86, p < 0.001, Nagelkerke R2 = 0.37). Before military acculturation, athletes had less intention to seek medical care for concussion, likely from prior athletic experiences.

United States Air Force Academy Cadets' Unprompted Knowledge of Concussions and "Bell Ringers" or "Dings": Perceived Differences and Similarities

CONTEXT

After a possible concussion mechanism, cadets are unlikely to have a list of concussion signs and symptoms at their disposal. As such, unprompted concussion knowledge may be an essential factor in personal recognition of injury.

OBJECTIVE

To explore determinants that contributed to United States Air Force Academy (USAFA) cadets' disclosure of a concussion. This research focused on 1 of 8 overall discovered themes of unprompted concussion knowledge.

DESIGN

Qualitative study.

SETTING

Military academy.

PATIENTS OR OTHER PARTICIPANTS

Cadets at the USAFA (males = 23, females = 11, age = 19.91 ± 1.14 years).

MAIN OUTCOME MEASURE(S)

We conducted 34 semistructured interviews. The transcribed text was analyzed in a 5-cycle process. From this process, 8 overall themes emerged, including unprompted concussion knowledge. Subthemes were concussion definition, concussion symptoms, "bell-ringer" or "ding" definition, "bell-ringer" or "ding" symptoms, and concussion versus "bell ringer" or "ding."

RESULTS

Many participants were able to describe a concussion fairly accurately. The most commonly listed concussion signs and symptoms were dizziness (n = 22/34, 64.7%); "can't remember"/"memory loss"/"forgetful" (n = 19/34, 55.9%); and headache (n = 16/34, 47.1%). The cadet participants characterized the most common bell-ringer or ding signs and symptoms as dizziness (n = 2/34, 5.9%) and headache (n = 2/34, 5.9%). Cadets also described how a bell ringer or ding differs from a concussion, often commenting that concussions were more severe than bell ringers or dings.

CONCLUSIONS

Overall, USAFA cadet participants listed common concussion signs and symptoms. However, they perceived differences between a concussion and a bell ringer or ding. Although decreasing the use of colloquial terms for concussion is recommended, use of these terms when examining a concussion history may be helpful. Concussion-education interventions should continue to focus on describing concussion signs and symptoms using cadets' own words to describe the injury (eg, "forgetful") but differentiating between what may and may not be a concussion and encouraging individuals to consult health care providers regarding possible concussion symptoms.

Number of prior concussions predict poorer concussion care seeking in military cadets

PRIMARY OBJECTIVE

To determine whether concussion history predicts concussion care seeking, self-management practices, or confidence to recognize/report.

RESEARCH DESIGN

Cross-sectional.

METHODS & PROCEDURES

706 United States Air Force Academy (USAFA) cadets completed survey items regarding concussion history (0,1,2,3+), likelihood of reporting a concussion, self-management, and confidence to recognize/report. We used multivariate ordinal and binary logistic regression models to predict responses using concussion history, sex, and race.Main outcomes & results: cadets with 1 (OR = 0.59, 95%CI:0.43-0.82), 2 (OR = 0.55, 95%CI:0.31-0.98), or 3+ (OR = 0.36, 95%CI:0.17-0.78) concussions while at USAFA had respective 41%, 45%, and 64% lower likelihood to report the concussion scenario (ref = no history, p < .001). USAFA cadets with more extensive concussion histories had higher prevalence of not seeking care for a concussion (p < .001); more strongly endorsed self-management (p = .001-0.010); and had greater confidence in their ability to recognize a concussion (p = .005), but not to report (p = .198-0.413).

CONCLUSIONS

Prior concussion experiences may deter cadets from seeking medical care for future concussions. Interventions should address concussion history and clinicians should consider how the post-concussion management process might deter care seeking.

Prolonged concussion effects: Constellations of cognitive deficits detected up to year after injury

Concussions are associated with an array of physical, emotional, cognitive, and sleep symptoms at multiple timescales. Cognitive recovery occurs relatively quickly – five-to-seven days on average. Yet, recent evidence suggests that some neurophysiological changes can be identified one year after a concussion. To that end, we examine more nuanced patterns in cognitive tests to determine whether cognitive abilities could identify a concussion within one-year post injury. A radial-basis (non-linear boundary) support vector machine classifier was trained to use cognitive performance measures to distinguish participants with no prior concussion from participants with prior concussion in the past year. After incorporating only 10 cognitive measures, or all 5 composite measures from the neurocognitive assessment (Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT)), over 90% accuracy was achieved in identifying both participants without prior concussions and participants with concussions in the past year, particularly when relying on non-linear patterns. Notably, classification accuracy stayed relatively constant between participants who had a concussion early or late in the one-year window. Thus, with substantial accuracy, a prior concussion can be identified using a non-linear combination of cognitive measures. Cognitive effects from concussion linger one-year post-injury, indicating the importance of continuing to follow concussion patients for many months after recovery and to take special note of constellations of cognitive abilities.

The Role of Social Support in Concussion Disclosure in United States Air Force Academy Cadets: A Mixed Methods Approach

INTRODUCTION

United States Air Force Academy (USAFA) cadets are at risk for sustaining concussions; however, several factors inhibit disclosure. We aimed to better understand the role of social support in concussion disclosure.

METHODS AND MATERIALS

We used a mixed methods approach with an electronic survey and interviews. The survey used a 9-point Likert scale (1 = strongly disagree and 9 = strongly agree) to assess concussion disclosure. Survey items asked cadets whom they felt most comfortable disclosing a concussion or bell-ringer/ding to, how quickly they would seek medical attention for a suspected concussion or bell-ringer/ding, whether cadets would be generally supportive/unsupportive of another cadet disclosing a concussion to medical staff, and whether other cadets important to them would be generally supportive/unsupportive if they reported a concussion to medical staff. Two multivariate linear regressions, one for concussion and one for bell-ringers/dings, were calculated to determine whether cadet choice of the person they felt most comfortable disclosing a concussion or bell-ringer/ding to predicted whether they would immediately seek medical attention for either condition. Choice of person included Air Officer Commanding (AOC)/Academy Military Trainer (AMT), upper classmen, cadet who had recovered from a concussion, cadet, closest friend, teammate, and squadmate. Descriptive analyses assessed whether cadets felt supported or unsupported by other cadets and by those who were important to them concerning concussion reporting. Thirty-four semi-structured interviews were conducted with cadets to explore their views on concussion disclosure.

RESULTS

Increased comfort with disclosing a suspected concussion to an AOC/AMT had higher agreement seeking medical attention (β = 0.28, P < .001). For every 1-point increase in being comfortable disclosing a potential bell-ringer/ding to an AOC/AMT (β = 0.272, P < .001), squadmate (β = 0.241, P = .002), and teammate (β = -0.182, P = .035), agreement for seeking medical attention immediately increased 0.27, increased 0.24, and decreased 0.18, respectively. Interviews indicated cadets would often speak to a peer before seeking medical attention.

CONCLUSIONS

Our results suggested that cadets felt comfortable reporting a suspected concussion or bell-ringer/ding to various peers and that those peers would be supportive of that choice, indicating social support. Future interventions should include educating cadets that peers may come to them, especially if they are AOCs/AMTs or squadmates.

Pluralistic Ignorance as a Contributing Factor to Concussion Underreporting

BACKGROUND

Concussion underreporting is endemic, and social norms are an established predictor of concussion reporting behavior. However, pluralistic ignorance-a situation in which most individuals in a group hold the belief that their peers' views differ from their own, despite views actually being similar-has not been studied in this context.

AIM

To assess whether pluralistic ignorance contributes to concussion underreporting.

METHOD

We surveyed 2,504 military service academy cadets. Each cadet was presented with a survey asking about their willingness to self-report a concussion, their perception of other cadets' willingness to report a concussion, and personal and demographic factors.

RESULTS

Most cadets viewed themselves as more willing to report a concussion than others (mean difference = 1.12, 95% CI [1.02, 1.21]), a belief consistent with pluralistic ignorance. Demographic characteristics were associated with holding this belief. For example, female cadets and upper-class cadets were more likely to show this disparity than male or under-class cadets, respectively. Collegiate athletes not only showed similar willingness to report concussion as nonathletes but also perceived other cadets as less likely to report concussions. Meanwhile, future pilots showed less self-report willingness and perceived that others were similarly unwilling to report concussions.

DISCUSSION

A majority of this economically and geographically diverse population displays characteristics of pluralistic ignorance: They largely share proconcussion reporting sentiments but incorrectly perceive that others do not. This belief is not held uniformly in all subpopulations, which may inform how these beliefs are developed and maintained.

CONCLUSIONS

Pluralistic ignorance is an important consideration in concussion education efforts.

Hearing Loss and Irritability Reporting Without Vestibular Differences in Explosive Breaching Professionals

Background: Blast exposure is a potential hazard in modern military operations and training, especially for some military occupations. Helmets, peripheral armor, hearing protection, and eye protection worn by military personnel provide some acute protection from blast effects but may not fully protect personnel against cumulative effects of repeated blast overpressure waves experienced over a career. The current study aimed to characterize the long-term outcomes of repeated exposure to primary blast overpressure in experienced career operators with an emphasis on the assessment of hearing and vestibular outcomes.

Methods: Participants included experienced “breachers” (military and law enforcement explosives professionals who gain entry into structures through controlled detonation of charges) and similarly aged and experienced “non-breachers” (non-breaching military and law enforcement personnel). Responses to a clinical interview and performance on audiological and vestibular testing were compared.

Results: Hearing loss, ringing in the ears, irritability, and sensitivity to light or noise were more common among breachers than non-breachers. Breachers reported more combat exposure than non-breachers, and subsequently, memory loss and difficulty concentrating were associated with both breaching and combat exposure. Vestibular and ocular motor outcomes were not different between breachers and non-breachers.

Conclusion: Hearing-related, irritability, and sensitivity outcomes are associated with a career in breaching. Future studies examining long-term effects of blast exposure should take measures to control for combat exposure.

Concussion-Recovery Trajectories Among Tactical Athletes: Results From the CARE Consortium

CONTEXT

Assessments of the duration of concussion recovery have primarily been limited to sport-related concussions and male contact sports. Furthermore, whereas durations of symptoms and return-to-activity (RTA) protocols encompass total recovery, the trajectory of each duration has not been examined separately.

OBJECTIVE

To identify individual (eg, demographics, medical history), initial concussion injury (eg, symptoms), and external (eg, site) factors associated with symptom duration and RTA-protocol duration after concussion.

DESIGN

Cohort study.

SETTING

Three US military service academies.

PATIENTS OR OTHER PARTICIPANTS

A total of 10 604 cadets at participating US military service academies enrolled in the study and completed a baseline evaluation and up to 5 postinjury evaluations. A total of 726 cadets (451 men, 275 women) sustained concussions during the study period.

MAIN OUTCOME MEASURE(S)

Number of days from injury (1) until the participant became asymptomatic and (2) to complete the RTA protocol.

RESULTS

Varsity athlete cadets took less time than nonvarsity cadets to become asymptomatic (hazard ratio [HR] = 1.75, 95% confidence interval = 1.38, 2.23). Cadets who reported less symptom severity on the Sport Concussion Assessment Tool, third edition (SCAT3), within 48 hours of concussion had 1.45 to 3.77 times shorter symptom-recovery durations than those with more symptom severity. Similar to symptom duration, varsity status was associated with a shorter RTA-protocol duration (HR = 1.74, 95% confidence interval = 1.34, 2.25), and less symptom severity on the SCAT3 was associated with a shorter RTA-protocol duration (HR range = 1.31 to 1.47). The academy that the cadet attended was associated with the RTA-protocol duration (P < .05).

CONCLUSIONS

The initial total number of symptoms reported and varsity athlete status were strongly associated with symptom and RTA-protocol durations. These findings suggested that external (varsity status and academy) and injury (symptom burden) factors influenced the time until RTA.

Distributed physiology and the molecular basis of social life in eusocial insects

The traditional focus of physiological and functional genomic research is on molecular processes that play out within a single multicellular organism. In the colonial (eusocial) insects such as ants, bees, and termites, molecular and behavioral responses of interacting nestmates are tightly linked, and key physiological processes are regulated at the scale of the colony. Such colony-level physiological processes regulate nestmate physiology in a distributed fashion, through various social communication mechanisms. As a result of physiological decentralization over evolutionary time, organismal mechanisms, for example related to pheromone detection, hormone signaling, and neural signaling pathways, are deployed in novel contexts to influence nestmate and colony traits. Here we explore how functional genomic, physiological, and behavioral studies can benefit from considering the traits of eusocial insects in this light. We highlight functional genomic work exploring how nestmate-level and colony-level traits arise and are influenced by interactions among physiologically-specialized nestmates of various developmental stages. We also consider similarities and differences between nestmate-level (organismal) and colony-level (superorganismal) physiological processes, and make specific hypotheses regarding the physiology of eusocial taxa. Integrating theoretical models of distributed systems with empirical functional genomics approaches will be useful in addressing fundamental questions related to the evolution of eusociality and collective behavior in natural systems.

United States Air Force Academy Cadets' Perceived Costs of Concussion Disclosure

INTRODUCTION

Concussion is unique among sport-related injuries as effective clinical diagnosis and treatment often rely on symptom-report for clinician diagnosis and treatment. However, at-risk populations such as collegiate athletes and military academy cadets often have been shown to under-report concussions and symptoms, complicating diagnosis, treatment, and policy-based interventions. The purpose of this study was to explore factors influencing concussion reporting in United States Air Force Academy (USAFA) cadets.

MATERIALS AND METHODS

Semi-structured interviews were conducted on 34 cadets (18 with concussion history; 16 without concussion history). This study was approved by the USAFA Institutional Review Board. Analysis included a five-cycle process of clarifying the topic at hand through an introduction, conducting a literature review, data collection and summarization, relating current findings to current literature, and making final interpretations. Data were summarized by creation of a codebook after reading five transcripts and identifying meaningful units. A four-person research team read and identified meaningful units individually, then met to discuss common meaningful units and codebook creation. Once the codebook was created, the lead researcher used the codebook to code all transcripts.

RESULTS

Eight themes were generated from interview transcripts. This manuscript focuses on the perceived costs following a concussion theme and the following subthemes: perceived costs to physical fitness, military career aspirations, pilot qualifications, sport, reputation, academics, and lack of time.

CONCLUSIONS

Cadet interviews described a complex environment where concussions were often viewed as costly to future career ambitions and provided potential reasons for non-disclosure largely including disruption in daily life. Reduction in perceived and actual harms due to concussion disclosure will require not only improving clinical care, but also addressing barriers to self-disclosure. Additionally, research suggests the sooner one reports a concussion, the sooner they return to physical or military activity. Educational interventions should be designed to address the perceived costs identified from our study and educate cadets that while some costs may be reality, others may not. Secondly, it should also be stressed to cadets that the sooner one seeks medical attention following a concussion, the sooner they may return to activity. Messaging around these themes may decrease the costs associated with time removed from academics, athletics, or military activities therefore minimizing attempts at concussion self-management. Lastly, if efforts are made to improve the overall concussion disclosure stigma, cadets may increase seeking care after injury because their reputation may not be as impacted.

A social dilemma model of information self-disclosure, applied to the concussion domain

Under-reporting of concussions is a well-known public health problem. Unfortunately, concussion researchers and practitioners do not have an explicit theoretical foundation for understanding the psychology of concussion non-disclosure. We used interdependence theory, a theory based on the structure of social relationships, to develop a social dilemma model of personal information non-disclosure and apply it to the concussion domain. Self-disclosure becomes problematic when individuals perceive a need to report their concussions but also perceive that disclosure could be detrimental in some way. Individuals who experience these disclosure dilemmas can evaluate the value of concussion self-disclosure using direct outcomes (e.g. losing scholarships, improved recovery), self-concept outcomes (e.g. viewing disclosure as “weak” or “sensible”), and social status outcomes (e.g. being perceived poorly or favorably by teammates). These immediate, personal outcomes are integrated with relationship-specific motives and ethical considerations ultimately leading to disclosure or non-disclosure. Providing an explicit theoretical basis for self-disclosure dilemmas is critical for understanding concussion non-disclosure and mitigating its corresponding harm. Our social dilemma model highlights (a) the foundational psychological basis for concussion non-disclosure, (b) possible reasons that initiatives designed to increase concussion disclosure have been ineffective, and (c) the need to consider the decision-making autonomy of concussed individuals. Although we explain our social dilemma model using concussion self-reporting, we believe that this model is applicable to any domain where individuals are reluctant to disclose personal information to others who need it.

Re-thinking the social ladder approach for elucidating the evolution and molecular basis of insect societies

The evolution of large insect societies is a major evolutionary transition that occurred in the long-extinct ancestors of termites, ants, corbiculate bees, and vespid wasps. Researchers have long used 'social ladder thinking': assuming progressive stepwise phenotypic evolution and asserting that extant species with simple societies (e.g. some halictid bees) represent the ancestors of species with complex societies, and thus provide insight into general early steps of eusocial evolution. We discuss how this is inconsistent with data and modern evolutionary 'tree thinking'. Phylogenetic comparative methods with broad sampling provide the best means to make rigorous inferences about ancestral traits and evolutionary transitions that occurred within each lineage, and to determine whether consistent phenotypic and genomic changes occurred across independent lineages.

Descriptive Analysis of a Baseline Concussion Battery Among U.S. Service Academy Members: Results from the Concussion Assessment, Research, and Education (CARE) Consortium

Introduction

The prevalence and possible long-term consequences of concussion remain an increasing concern to the U.S. military, particularly as it pertains to maintaining a medically ready force. Baseline testing is being used both in the civilian and military domains to assess concussion injury and recovery. Accurate interpretation of these baseline assessments requires one to consider other influencing factors not related to concussion. To date, there is limited understanding, especially within the military, of what factors influence normative test performance. Given the significant physical and mental demands placed on service academy members (SAM), and their relatively high risk for concussion, it is important to describe demographics and normative profile of SAMs. Furthermore, the absence of available baseline normative data on female and non-varsity SAMs makes interpretation of post-injury assessments challenging. Understanding how individuals perform at baseline, given their unique individual characteristics (e.g., concussion history, sex, competition level), will inform post-concussion assessment and management. Thus, the primary aim of this manuscript is to characterize the SAM population and determine normative values on a concussion baseline testing battery.

Materials and Methods

All data were collected as part of the Concussion Assessment, Research and Education (CARE) Consortium. The baseline test battery included a post-concussion symptom checklist (Sport Concussion Assessment Tool (SCAT), psychological health screening inventory (Brief Symptom Inventory (BSI-18) and neurocognitive evaluation (ImPACT), Balance Error Scoring System (BESS), and Standardized Assessment of Concussion (SAC). Linear regression models were used to examine differences across sexes, competition levels, and varsity contact levels while controlling for academy, freshman status, race, and previous concussion. Zero inflated negative binomial models estimated symptom scores due to the high frequency of zero scores.

Results

Significant, but small, sex effects were observed on the ImPACT visual memory task. While, females performed worse than males (p < 0.0001, pη2 = 0.01), these differences were small and not larger than the effects of the covariates. A similar pattern was observed for competition level on the SAC. There was a small, but significant difference across competition level. SAMs participating in varsity athletics did significantly worse on the SAC compared to SAMs participating in club or intramural athletics (all p's < 0.001, η2 = 0.01). When examining symptom reporting, males were more than two times as likely to report zero symptoms on the SCAT or BSI-18. Intramural SAMs had the highest number of symptoms and severity compared to varsity SAMs (p < 0.0001, Cohen's d < 0.2). Contact level was not associated with SCAT or BSI-18 symptoms among varsity SAMs. Notably, the significant differences across competition level on SCAT and BSI-18 were sub-clinical and had small effect sizes.

Conclusion

The current analyses provide the first baseline concussion battery normative data among SAMs. While statistically significant differences may be observed on baseline tests, the effect sizes for competition and contact levels are very small, indicating that differences are likely not clinically meaningful at baseline. Identifying baseline differences and significant covariates is important for future concussion-related analyses to inform concussion evaluations for all athlete levels.

A Report on a Novice User's Interaction with the Internet through a Self-Voicing Application

This study used verbal protocol analysis to examine the behavior of an individual with visual impairment using a self-voicing application to find information on the World Wide Web. The results indicated that executing actions (such as typing or pressing keys) and interpreting the computer system's state (data gathering) were the most frequent and time-consuming tasks. Furthermore, the individual had difficulty determining the effects of her actions on the system and whether relevant information was present on a page. These results suggest that there may be problems in interfacing the user with the software and the way textual information is aurally displayed to the user.

Pilots and athletes: Different concerns, similar concussion non-disclosure

Objectives

Concussion non-disclosure research has focused almost exclusively on athletes. The focus on athletic populations has been sensible considering athletes’ demonstrated susceptibility to sustaining and concealing concussions. Nevertheless, the habitual use of athletic populations has allowed researchers and practitioners to omit the development of generalized perceived costs and perceived rewards as critical determinants of concussion self-disclosure. We hypothesized that perceiving concussion disclosure as generally more costly than rewarding would predict negative attitudes towards disclosure and decreased intent to disclose. We also hypothesized that generalized perceived costs and rewards could explain concussion non-disclosure in different populations, athletes and future pilots specifically, even when those populations perceive concussion self-disclosure as costly for different specific reasons.

Methods

We examined concussion disclosure using 2,504 cadets at the United States Air Force Academy. Cadets completed anonymous surveys assessing their intention to self-disclose undiagnosed concussions (Anticipated Concussion Disclosure) as well as several variables potentially related to concussion self-disclosure: perceived cost, perceived reward, personal identity, attitudes, normative behavior, social support, and self-efficacy.

Results

The results demonstrate that concussion non-disclosure develops when a population perceives disclosure as more costly (i.e. directly or emotionally) and less rewarding. Perceived Cost and Perceived Reward variables alone accounted for 50% of the variance in Anticipated Conclusion Disclosure (Adjusted R²= 0.50, F(2,2312) = 1,145.31, p < 0.001). As expected, Anticipated Conclusion Disclosure developed for different reasons within different sub-populations. Consistent with existing research, cadet intercollegiate athletes reported being primarily concerned that concussion self-disclosure would cause them to miss practice or game time (t (736.7) = 14.20, p < .001, Cohen’s d = 0.96). In contrast, cadet future pilots reported being primarily concerned that concussion self-disclosure would have negative United States Air Force career repercussions (t (1828) = 10.25, p < .001, Cohen’s d = 0.50).

Conclusions

These results suggest that cultures of concussion non-disclosure can develop in any population where disclosure is perceived as having undesirable consequences, not just athletic populations. Concussion researchers and practitioners should devote more attention to the perceived cost-benefit structures that create concussion non-disclosure to address this crucial public health issue more effectively.

Predictive Power of Head Impact Intensity Measures for Recognition Memory Performance

Subconcussive head injuries are connected to both short-term cognitive changes and long-term neurodegeneration. Further study is required to understand what types of subconcussive impacts might prove detrimental to cognition. We studied cadets at the US Air Force Academy engaged in boxing and physical development, measuring head impact motions during exercise with accelerometers. These head impact measures were compared with post-exercise memory performance. Investigators explored multiple techniques for characterizing the magnitude of head impacts. Boxers received more head impacts and achieved lower performance in post-exercise memory than non-boxers. For several measures of impact motion, impact intensity appeared to set an upper bound on post-exercise memory performance - stronger impacts led to lower expected memory performance. This trend was most significant when impact intensity was measured through a novel technique, applying principal component analysis to boxer motion. Principal component analysis measures also captured more distinct impact information than seven traditional impact measures also tested.

The digestive system in Zygentoma as an insect model for high cellulase activity

The digestive system of selected phytophagous insects has been examined as a potential prospecting resource for identification of novel cellulolytic enzymes with potential industrial applications. In contrast to other model species, however, limited detailed information is available that characterizes cellulolytic activity and systems in basal hexapod groups. As part of a screening effort to identify insects with highly active cellulolytic systems, we have for the first time, identified species of Zygentoma that displayed the highest relative cellulase activity levels when compared to all other tested insect groups under the experimental conditions, including model species for cellulolytic systems such as termite and cockroach species in Rhinotermitidae (formerly Isoptera) and Cryptocercidae (formerly Blattodea). The goal of the present study was to provide a morphohistological characterization of cellulose digestion and to identify highly active cellulase enzymes present in digestive fluids of Zygentoma species. Morphohistological characterization supported no relevant differences in the digestive system of firebrat (Thermobia domestica) and the gray silverfish (Ctenolepisma longicaudata). Quantitative and qualitative cellulase assays identified the foregut as the region with the highest levels of cellulase activity in both T. domestica and C. longicaudata. However, T. domestica was found to have higher endoglucanase, xylanase and pectinase activities compared to C. longicaudata. Using nano liquid chromatography coupled to tandem mass spectrometry (nanoLC/MS/MS) and a custom gut transcriptome we identified cellulolytic enzymes from digestive fluids of T. domestica. Among the identified enzymes we report putative endoglucanases matching to insect or arthropod enzymes and glucan endo-1,6-β-glucosidases matching bacterial enzymes. These findings support combined activities of endogenous and symbiont-derived plant cell wall degrading enzymes in lignocellulose digestion in Zygentoma and advance our understanding of cellulose digestion in a primitive insect group.

A cohort study to identify and evaluate concussion risk factors across multiple injury settings: findings from the CARE Consortium

Background

Concussion, or mild traumatic brain injury, is a major public health concern affecting 42 million individuals globally each year. However, little is known regarding concussion risk factors across all concussion settings as most concussion research has focused on only sport-related or military-related concussive injuries.

Methods

The current study is part of the Concussion, Assessment, Research, and Education (CARE) Consortium, a multi-site investigation on the natural history of concussion. Cadets at three participating service academies completed annual baseline assessments, which included demographics, medical history, and concussion history, along with the Sport Concussion Assessment Tool (SCAT) symptom checklist and Brief Symptom Inventory (BSI-18). Clinical and research staff recorded the date and injury setting at time of concussion. Generalized mixed models estimated concussion risk with service academy as a random effect. Since concussion was a rare event, the odds ratios were assumed to approximate relative risk.

Results

Beginning in 2014, 10,604 (n = 2421, 22.83% female) cadets enrolled over 3 years. A total of 738 (6.96%) cadets experienced a concussion, 301 (2.84%) concussed cadets were female. Female sex and previous concussion were the most consistent estimators of concussion risk across all concussion settings. Compared to males, females had 2.02 (95% CI: 1.70–2.40) times the risk of a concussion regardless of injury setting, and greater relative risk when the concussion occurred during sport (Odds Ratio (OR): 1.38 95% CI: 1.07–1.78). Previous concussion was associated with 1.98 (95% CI: 1.65–2.37) times increased risk for any incident concussion, and the magnitude was relatively stable across all concussion settings (OR: 1.73 to 2.01). Freshman status was also associated with increased overall concussion risk, but was driven by increased risk for academy training-related concussions (OR: 8.17 95% CI: 5.87–11.37). Medical history of headaches in the past 3 months, diagnosed ADD/ADHD, and BSI-18 Somatization symptoms increased overall concussion risk.

Conclusions

Various demographic and medical history factors are associated with increased concussion risk. While certain factors (e.g. sex and previous concussion) are consistently associated with increased concussion risk, regardless of concussion injury setting, other factors significantly influence concussion risk within specific injury settings. Further research is required to determine whether these risk factors may aid in concussion risk reduction or prevention.

Electronic supplementary material

The online version of this article (10.1186/s40621-018-0178-3) contains supplementary material, which is available to authorized users.

Taxonomically Restricted Genes Are Fundamental to Biology and Evolution

Genes limited to particular clades, taxonomically restricted genes (TRGs), are common in all sequenced genomes. TRGs have recently become associated with the evolution of novelty, as numerous studies across the tree of life have now linked expression of TRGs with novel phenotypes. However, TRGs that underlie ancient lineage specific traits have been largely omitted from discussions of the general importance of TRGs. Here it is argued that when all TRGs are considered, it is apparent that TRGs are fundamental to biology and evolution and likely play many complementary roles to the better understood toolkit genes. Genes underlying photosynthesis and skeletons, for example, are examples of commonplace fundamental TRGs. Essentially, although basic cell biology has a highly conserved genetic basis across the tree of life, most major clades also have lineage specific traits central to their biology and these traits are often based on TRGs. In short, toolkit genes underlie what is conserved across organisms, while TRGs define in many cases what is unique. An appreciation of the importance of TRGs will improve our understanding of evolution by triggering the study of neglected topics in which TRGs are of paramount importance.

The origin of the odorant receptor gene family in insects

The origin of the insect odorant receptor (OR) gene family has been hypothesized to have coincided with the evolution of terrestriality in insects. Missbach et al. (2014) suggested that ORs instead evolved with an ancestral OR co-receptor (Orco) after the origin of terrestriality and the OR/Orco system is an adaptation to winged flight in insects. We investigated genomes of the Collembola, Diplura, Archaeognatha, Zygentoma, Odonata, and Ephemeroptera, and find ORs present in all insect genomes but absent from lineages predating the evolution of insects. Orco is absent only in the ancestrally wingless insect lineage Archaeognatha. Our new genome sequence of the zygentoman firebrat Thermobia domestica reveals a full OR/Orco system. We conclude that ORs evolved before winged flight, perhaps as an adaptation to terrestriality, representing a key evolutionary novelty in the ancestor of all insects, and hence a molecular synapomorphy for the Class Insecta.