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The purpose of this study was to examine sex differences in neuropsychological functioning after sports-related concussion using several approaches to assess cognition: mean performance, number of impaired scores, and intraindividual variability (IIV).
In the study, 152 concussed college athletes were administered a battery of neuropsychological tests, on average, 10 days post-concussion (SD = 12.75; Mdn = 4 days; Range = 0–72 days). Mean performance was evaluated across 18 individual neuropsychological variables, and the total number of impaired test scores (>1.5 SD below the mean) was calculated for each athlete. Two measures of IIV were also computed: an intraindividual standard deviation (ISD) score and a maximum discrepancy (MD) score.
Analyses of covariance revealed that, compared with males, females had significantly more impaired scores and showed greater variability on both IIV indices (ISD and MD scores) after adjusting for time since injury and post-concussive symptoms. In contrast, no significant effects of sex were found when examining mean neuropsychological performance.
Although females and males demonstrated similar mean performance following concussion, females exhibited a greater level of cognitive impairment and larger inconsistencies in cognitive performance than males. These results suggest that evaluating cognitive indices beyond mean neuropsychological scores may provide valuable information when determining the extent of post-concussion cognitive dysfunction. (JINS, 2019, 00, 1–7)
Objectives: Research indicates that symptoms following a concussion are related to cognitive dysfunction; however, less is known about how different types of symptoms may be related to cognitive outcomes or how specific domains of cognition are affected. The present study explored the relationship between specific types of symptoms and these various cognitive outcomes following a concussion. Methods: One-hundred twenty-two student-athletes with sports-related concussion were tested with a battery that included a symptom report measure and various cognitive tests. Symptoms factors were: Physical, Sleep, Cognitive, Affective and Headache. Participants were grouped into “symptom” and “no symptom” groups for each factor. Cognitive outcomes included both overall performance as well as impairment scores in which individuals were grouped into impaired and not impaired based on a cutoff of 2 or more tests at the impaired level (<80 in standard scores). These cognitive outcomes were examined for all the tests combined and then specifically for the memory tests and attention/processing speed tests. A Bonferroni correction was used, and the results were considered significant at a level of p<.008. Results: Headache symptoms were significantly (p<.008) associated with overall cognitive impairment as well as memory and attention/processing speed impairment. Sleep symptoms were related to memory impairments. Conclusions: The symptom specific relationships to cognitive outcomes demonstrated by our study can help guide treatment and accommodations for athletes following concussion. (JINS, 2018, 24, 1–9)
Explosions of massive stars (8 ≲ M/M⊙ ≲ 70) are examined as the source of galactic cosmic rays. Detailed nucleosynthetic and evolutionary calculations suggest that these massive stars produce the heavy elements (carbon and above) in their proper relative abundances. This is particularly significant because lower mass stars (in particular the 4–8 M⊙ range) are not able to produce the observed abundances of C and O relative to the iron peak. A small (~ 1.4 M⊙) dense remnant star (a neutron star) left after the explosion may provide a location for an electromagnetic acceleration mechanism. Those abundance ratios which can now be predicted (He, C, O, Ne, Mg) for the material to be accelerated by the pulsar give a reasonable match to the observed cosmic ray data. The conditions at the outer edge of the remnant and the inner edge of the ejected material may be appropriate for an r-process to occur; the high Z cosmic rays seem to show an enrichment of r-process material. It appears that these stars may be the astrophysical source for the galactic cosmic rays. The questions of rotation and black hole formation were discussed. It appears that the most straight-forward result of evolution of a close massive binary is a massive star and a neutron star in a low eccentricity orbit, in agreement with observation.
Massive stars have a strong impact on their surroundings, in particular when they produce a core-collapse supernova at the end of their evolution. In these proceedings, we review the general evolution of massive stars and their properties at collapse as well as the transition between massive and intermediate-mass stars. We also summarise the effects of metallicity and rotation. We then discuss some of the major uncertainties in the modelling of massive stars, with a particular emphasis on the treatment of convection in 1D stellar evolution codes. Finally, we present new 3D hydrodynamic simulations of convection in carbon burning and list key points to take from 3D hydrodynamic studies for the development of new prescriptions for convective boundary mixing in 1D stellar evolution codes.
This special issue focuses on literary texts by African writers in which the protagonist returns to his/her "original" or ancestral "home" in Africa from other parts of the world. Ideas of return - intentional and actual - have been a consistent feature of the literature of Africa and the African diaspora: from Equiano's autobiography in 1789 to Chimamanda Ngozi Adichie's 2013 novel Americanah. African literature has represented returnees in a range of locations and dislocations including having a sense of belonging, being alienated in a country they can no longer recognize, or experiencing a multiple sense of place. Contributors, writing on literature from the 1970s to the present, examine the extent to which the original place can be reclaimed with or without renegotiations of "home".
GUEST EDITORS: HELEN COUSINS, Reader in Postcolonial Literature at Newman University, Birmingham, UK; PAULINE DODGSON-KATIYO, Head of English at Newman University, Birmingham, UK.
Series Editor: Ernest Emenyonu is Professor of Africana Studies at the University of Michigan-Flint, USA.
The reasons for leaving home are myriad: war, famine, economic hardship, better opportunity, survival. Suffice to say, displacement would not need to occur – would not happen nearly so often – if the places from which migrants and refugees flee were sustaining and supportive. As such, many immigrant and refugee fictions are deeply imbued with the trauma of origin. There is nothing that the subject can do about this original trauma, as in the guilt of original sin, and Sepha Stephanos, the Ethiopian refugee at the centre of Dinaw Mengestu's novel The Beautiful Things That Heaven Bears is one such displaced person. He fled Ethiopia during the Red Terror, and finds himself plunged into immigrant America. In his most recent incarnation, he is the manager of a dilapidated corner store in Logan Circle, Washington, DC, where he becomes close to a new resident, Judith, and her precocious daughter, Naomi. This child, early in the novel, has ‘run away’ from her home to seek refuge in Stephanos’ corner store. By way of reaching out to her, Stephanos explains, ‘“I used to run away all the time when I was a child.” She smiled back gratefully at me…“And how did your mom get you to stop?” “She didn't. That's how I ended up here”’ (Mengestu: 26). Stephanos makes it clear that there are many routes to emigration, to refuge, but not all concerned with the same ends: ‘As it was, I did not come to America to find a better life. I came here running and screaming with the ghosts of an old one firmly attached to my back. My goal since then has always been a simple one: to persist unnoticed through the days, to do no more harm’ (41). This declaration makes clear the central problematic of the novel: the shame, guilt, and affective numbing that accompanies his long-term experience of depression in displacement. Shame, Timothy Bewes convincingly argues, is inherent in the form of postcolonial writing, proceeding from the premise that ‘shame appears overtly, as the [postcolonial] text's experience of its own inadequacy’ (The Event of Postcolonial Shame: 3), an inadequacy inscribed in the circuitry between the writer and the text, and the text and its audience.
For almost a decade, George Eliot labored at a translation of seventeenth-century Jewish philosopher Baruch Spinoza's Tractatus Theologico-Politicus and Ethics, and although completed, it never saw the light of day; it was the subject of a petty fight between the proposed publisher, Henry Bohn, and her partner, George Henry Lewes. The result was that for more than a century it was tucked away, first, presumably, in a drawer, and eventually, in the Beinecke Library at Yale University. Although critics and scholars have long known that she had completed this work – references abound in letters and journal entries – it wasn't published until 1981, and even then, in an obscure imprint of the Salzburg University press. Copies of this published edition, which is limited to the Ethics and capably annotated by Thomas Deegan, are quite rare and difficult to get ahold of.
We present the first detailed three-dimensional hydrodynamic implicit large eddy simulations of turbulent convection for carbon burning. The simulations start with an initial radial profile mapped from a carbon burning shell within a 15 M⊙ stellar evolution model. We considered 4 resolutions from 1283 to 10243 zones. These simulations confirm that convective boundary mixing (CBM) occurs via turbulent entrainment as in the case of oxygen burning. The expansion of the boundary into the surrounding stable region and the entrainment rate are smaller at the bottom boundary because it is stiffer than the upper boundary. The results of this and similar studies call for improved CBM prescriptions in 1D stellar evolution models.
The possible nature of the first generation of stars is considered, using a star of 25M⊙ as an example. General nucleosynthesis and the production of CNO catalysts is examined in detail. The increase in neutron excess and its significance for yields from explosive burning is discussed. An estimate of the ratio of ionizing photons to heavy elements produced is derived, for use in early universe simulations.