RESUMEN

Understanding the respiratory modes of sharks has important implications for studying the metabolism, energetics, and behavioral strategies of different species. Here we provide the first reported observations of resting behavior in the gray reef shark Carcharhinus amblyrhynchos, a species typically considered an obligate ram ventilator. Observations were made at several locations in the Republic of Seychelles, where sharks were found resting under reef ledges and were unresponsive to the presence of divers. These findings update our understanding of the respiratory mode of this species and have implications for future research.

Asunto(s)

RESUMEN

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.

Asunto(s)

RESUMEN

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 (ß = 0.80, p = 0.026). Athletes demonstrated greater brain health knowledge by nearly one symptom correctly identified (ß = 0.98, p = 0.002); non-athletes reported significantly greater ACR (ß = 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.

Asunto(s)

RESUMEN

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 (ß = 0.28, P < .001). For every 1-point increase in being comfortable disclosing a potential bell-ringer/ding to an AOC/AMT (ß = 0.272, P < .001), squadmate (ß = 0.241, P = .002), and teammate (ß = -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.

Asunto(s)

RESUMEN

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.

Asunto(s)

RESUMEN

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.

Asunto(s)

RESUMEN

Although ctenophores can be conspicuous components of the plankton in coastal marine ecosystems, only six species have been formally described from around South Africa. Using photographs from local community scientists, we add a further three species (Cestum veneris, Beroe forskalii?, Ocyropsis maculata?) and six morphospecies to the regional fauna. These additions suggest that South Africa has a ctenophore fauna that is amongst the most diverse, globally; an observation in agreement with information from other taxa. Tips on how community scientists can improve their photographic contributions to understanding ctenophore diversity are provided.

RESUMEN

Millions of people worldwide live with corneal opacity, which continues to be one of the leading causes of blindness. Corneal opacity is treatable. However, the surgical methods for treating this condition, such as corneal transplantation and keratoprosthesis, have many complications. The use of an intraocular projector is a promising approach to treat corneal blindness. Like any device using electrical power, an intraocular projection device produces heat, which could potentially damage eye tissue. Australian and international standards state that there cannot be an increase of temperature of 2 °C caused by an implanted device. In order to determine if these standards are met, a 2D axisymmetric thermal analysis of the projector in the human eye is conducted in ANSYS Workbench. With the projector operating at its maximum wattage, our analysis shows that an air gap extension within the projector will help maintain the temperature increase below 2 °C.

RESUMEN

Corneal opacity is a leading cause of blindness worldwide. Corneal transplantation and keratoprosthesis can restore vision but have limitations due to the shortage of donor corneas and complications due to infection. A proposed alternative treatment using an intraocular projection prosthesis device can treat corneal disease. In this study, we perform a transient thermal analysis of the bionic eye model to determine the power the device can produce without elevating the eye tissue temperature above the 2°C limit imposed by the international standard for implantable devices. A 3D finite element model, including blood perfusion and natural convection fluid flow of the eye, was created. The device was placed 1.95 mm from the iris, which experienced less than 2°C rise in the tissue temperature at a maximum power dissipation of LED at 100 mW and microdisplay at 25 mW.

RESUMEN

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.

Asunto(s)

RESUMEN

B7 family members and their receptors play a central role in the regulation of T-cell responses through T-cell co-stimulation and co-inhibition pathways that constitute attractive targets for the development of immunotherapeutic drugs. In this study, we report that VSIG-3/IGSF11 is a ligand of B7 family member VISTA/PD-1H and inhibits human T-cell functions through a novel VSIG-3/VISTA pathway. An extensive functional ELISA binding screening assay reveals that VSIG-3 binds to the new B7 family member VISTA but does not interact with other known members of the B7 family. Under the same experimental conditions, we did not observe any significant interaction between VSIG-8 and VISTA. In addition, VSIG-3 inhibits human T-cell proliferation in the presence of T-cell receptor signaling. Furthermore, VSIG-3 significantly reduces cytokine and chemokine production by human T cells including IFN-γ, IL-2, IL-17, CCL5/Rantes, CCL3/MIP-1α, and CXCL11/I-TAC. Anti-VISTA neutralization antibodies attenuate the binding of VSIG-3 and VISTA, as well as VSIG-3-induced T-cell inhibition. Hence, we have identified a novel ligand for VISTA that is able to inhibit human T-cell proliferation and cytokine production. This unique VSIG-3/VISTA co-inhibitory pathway may provide new strategies for the treatment of human cancers, autoimmune disorders, infection, and transplant rejection and may aid in the design of better vaccines.

Asunto(s)

Asunto(s)

RESUMEN

Graphene has served as the model 2D system for over a decade, and the effects of grain boundaries (GBs) on its electrical and mechanical properties are very well investigated. However, no direct measurement of the correlation between thermal transport and graphene GBs has been reported. Here, we report a simultaneous comparison of thermal transport in supported single crystalline graphene to thermal transport across an individual graphene GB. Our experiments show that thermal conductance (per unit area) through an isolated GB can be up to an order of magnitude lower than the theoretically anticipated values. Our measurements are supported by Boltzmann transport modeling which uncovers a new bimodal phonon scattering phenomenon initiated by the GB structure. In this novel scattering mechanism, boundary roughness scattering dominates the phonon transport in low-mismatch GBs, while for higher mismatch angles there is an additional resistance caused by the formation of a disordered region at the GB. Nonequilibrium molecular dynamics simulations verify that the amount of disorder in the GB region is the determining factor in impeding thermal transport across GBs.

RESUMEN

Why do mouse corneal epithelial cells display spiraling patterns? We want to provide an explanation for this phenomenon by applying an idealized problem solving process. Specifically, we applied complementary line-fitting methods to measure transgenic epithelial reporter expression arrangements displayed on three mature, live enucleated globes to clarify the problem. Two prominent logarithmic curves were discovered, one of which displayed the ϕ ratio, an indicator of the optimal configuration in phyllotactic systems. We then utilized two different computational approaches to expose our current understanding of the behavior. In one procedure, which involved an isotropic mechanics-based finite element method, we successfully produced logarithmic spiral curves of maximum shear strain based pathlines but computed dimensions displayed pitch angles of 35° (ϕ spiral is ~17°), which was altered when we fitted the model with published measurements of coarse collagen orientations. We then used model-based reasoning in context of Peircean abduction to select a working hypothesis. Our work serves as a concise example of applying a scientific habit of mind and illustrates nuances of executing a common method to doing integrative science.

RESUMEN

The cornea is a transparent tissue in front of the eye that refracts light and facilitates vision. A slight change in the geometry of the cornea remarkably affects the optical power. Because of this sensitivity, biomechanical study of the cornea can reveal much about its performance and function. In vivo and in vitro studies have been conducted to investigate the mechanics of the cornea and determine its characteristics. Numerical techniques such as the finite element method (FEM) have been extensively implemented as effective and noninvasive methods for analyzing corneal mechanics and possible disorders. This article reviews the use of FEM for assessing the mechanical behavior of the cornea. Different applications of FEM in corneal disease studies, surgical predictions, impact simulations, and clinical applications have been reviewed. Some suggestions for the future of this type of modeling in the area of corneal mechanics are also discussed.

Asunto(s)

RESUMEN

The cornea is a transparent tissue in front of the eye that refracts light and facilitates vision. A slight change in the geometry of the cornea remarkably affects the optical power. Because of this sensitivity, biomechanical study of the cornea can reveal much about its performance and function. In vivo and in vitro studies have been conducted to investigate the mechanics of the cornea and determine its characteristics. Numerical techniques such as the finite element method (FEM) have been extensively implemented as effective and noninvasive methods for analyzing corneal mechanics and possible disorders. This article reviews the use of FEM for assessing the mechanical behavior of the cornea. Different applications of FEM in corneal disease studies, surgical predictions, impact simulations, and clinical applications have been reviewed. Some suggestions for the future of this type of modeling in the area of corneal mechanics are also discussed.

A córnea é um tecido transparente na parte frontal do olho, que refrata a luz e torna a visão possível. Uma ligeira alteração na geometria da córnea notavelmente afeta a sua potência óptica. Devido a essa sensibilidade, o estudo biomecânico da córnea pode revelar muito sobre o seu desempenho e funcionalidade. Estudos in vivo e in vitro foram realizados para investigar a mecânica da córnea e para determinar suas características. Técnicas numéricas como o método dos elementos finitos (FEM) foram amplamente implementadas como métodos eficazes e não invasivos de análise mecânica da córnea e seus possíveis transtornos. Este artigo analisa o uso de FEM para avaliar o comportamento mecânico da córnea. Diferentes aplicações da FEM no estudo de doenças da córnea, previsões cirúrgicas, simulações de impacto e aplicações clínicas foram revistos. São discutidas algumas sugestões para o futuro deste tipo de modelagem na área de mecânica de córnea.

Asunto(s)

RESUMEN

Are secret romances alluring or aversive? One theory suggests that romantic secrecy increases obsessive preoccupation with romantic partners and thereby enhances romantic relationships. Another theory suggests that romantic secrecy is burdensome and thereby undermines romantic relationships. We sought to rectify these conflicting perspectives by examining romantic secrecy and relationship duration using a large, Internet-based sample (N = 564). We predicted that romantic secrecy would have a positive influence in newer romantic relationships (obsessive preoccupation theory) and a negative influence in older romantic relationships (burden theory). In contrast, the obtained results indicate that romantic secrecy is a burden to both new and old romantic relationships.

Asunto(s)

RESUMEN

High-speed biplane x-ray and neutral density targets were used to examine brain displacement and deformation during impact. Relative motion, maximum principal strain, maximum shear strain, and intracranial pressure were measured in thirty-five impacts using eight human cadaver head and neck specimens. The effect of a helmet was evaluated. During impact, local brain tissue tends to keep its position and shape with respect to the inertial frame, resulting in relative motion between the brain and skull and deformation of the brain. The local brain motions tend to follow looping patterns. Similar patterns are observed for impact in different planes, with some degree of posterior-anterior and right-left symmetry. Peak coup pressure and pressure rate increase with increasing linear acceleration, but coup pressure pulse duration decreases. Peak average maximum principal strain and maximum shear are on the order of 0.09 for CFC 60 Hz data for these tests. Peak average maximum principal strain and maximum shear decrease with increasing linear acceleration, coup pressure, and coup pressure rate. Linear and angular acceleration of the head are reduced with use of a helmet, but strain increases. These results can be used for the validation of finite element models of the human head.

Asunto(s)

RESUMEN

This study characterizes the response of the human cadaver abdomen to high-speed seatbelt loading using pyrotechnic pretensioners. A test apparatus was developed to deliver symmetric loading to the abdomen using a seatbelt equipped with two low-mass load cells. Eight subjects were tested under worst-case scenario, out-of-position (OOP) conditions. A seatbelt was placed at the level of mid-umbilicus and drawn back along the sides of the specimens, which were seated upright using a fixed-back configuration. Penetration was measured by a laser, which tracked the anterior aspect of the abdomen, and by high-speed video. Additionally, aortic pressure was monitored. Three different pretensioner designs were used, referred to as system A, system B and system C. The B and C systems employed single pretensioners. The A system consisted of two B system pretensioners. The vascular systems of the subjects were perfused. Peak anterior abdominal loads due to the seatbelt ranged from 2.8 kN to 10.1 kN. Peak abdominal penetration ranged from 49 mm to 138 mm. Peak penetration speed ranged from 4.0 m/s to 13.3 m/s. Three cadavers sustained liver injury: one AIS 2, and two AIS 3. Cadaver abdominal response corridors for the A and B system pretensioners are proposed. The results are compared to the data reported by Hardy et al. (2001) and Trosseille et al. (2002).

Asunto(s)

RESUMEN

Five studies investigated the links among narcissism, self-esteem, and love. Across all studies, narcissism was associated primarily with a game-playing love style. This link was found in reports of general love styles (Study 1a) and of love in ongoing romantic relationships (Studies 1b-3, 5). Narcissists' game-playing love style was the result of a need for power and autonomy (Study 2) and was linked with greater relationship alternatives and lesser commitment (Study 3). Finally, narcissists' self-reports of game playing were confirmed by their partners in past and current relationships (Studies 4, 5). In contrast, self-esteem was negatively linked to manic love and positively linked to passionate love across studies. Implications for the understanding of narcissism in relationships are discussed.

Asunto(s)