We recently reported on the radio-frequency attenuation length of cold polar ice at Summit Station, Greenland, based on bi-static radar measurements of radio-frequency bedrock echo strengths taken during the summer of 2021. Those data also allow studies of (a) the relative contributions of coherent (such as discrete internal conducting layers with sub-centimeter transverse scale) vs incoherent (e.g. bulk volumetric) scattering, (b) the magnitude of internal layer reflection coefficients, (c) limits on signal propagation velocity asymmetries (‘birefringence’) and (d) limits on signal dispersion in-ice over a bandwidth of ~100 MHz. We find that (1) attenuation lengths approach 1 km in our band, (2) after averaging 10 000 echo triggers, reflected signals observable over the thermal floor (to depths of ~1500 m) are consistent with being entirely coherent, (3) internal layer reflectivities are ≈–60$\to$–70 dB, (4) birefringent effects for vertically propagating signals are smaller by an order of magnitude relative to South Pole and (5) within our experimental limits, glacial ice is non-dispersive over the frequency band relevant for neutrino detection experiments.

Over the last 25 years, radiowave detection of neutrino-generated signals, using cold polar ice as the neutrino target, has emerged as perhaps the most promising technique for detection of extragalactic ultra-high energy neutrinos (corresponding to neutrino energies in excess of 0.01 Joules, or 1017 electron volts). During the summer of 2021 and in tandem with the initial deployment of the Radio Neutrino Observatory in Greenland (RNO-G), we conducted radioglaciological measurements at Summit Station, Greenland to refine our understanding of the ice target. We report the result of one such measurement, the radio-frequency electric field attenuation length $L_\alpha$. We find an approximately linear dependence of $L_\alpha$ on frequency with the best fit of the average field attenuation for the upper 1500 m of ice: $\langle L_\alpha \rangle = ( ( 1154 \pm 121) - ( 0.81 \pm 0.14) \, ( \nu /{\rm MHz}) ) \,{\rm m}$ for frequencies ν ∈ [145 − 350] MHz.

This study examined how youth aggressive and delinquent externalizing problem behaviors across childhood and adolescence are connected to consequential psychosocial life outcomes in adulthood. Using data from a longitudinal, high-risk sample (N = 1069) that assessed children and their parents regularly from early childhood (ages 3–5) through adulthood, multilevel growth factors of externalizing behaviors were used to predict adult outcomes (age 24–31), providing a sense of how externalizing problems across development were related to these outcomes via maternal, paternal, teacher, and child report. Findings indicated strong support for the lasting connections between youth externalizing problems with later educational attainment and legal difficulties, spanning informants and enduring beyond other meaningful contributors (i.e., child sex, cognitive ability, parental income and education, parental mental health and relationship quality). Some support was also found, although less consistently, linking externalizing problems and later alcohol use as well as romantic relationship quality. Delinquent/rule-breaking behaviors were often stronger predictors of later outcomes than aggressive behaviors. Taken together, these results indicate the importance of the role youth externalizing behaviors have in adult psychosocial functioning one to two decades later.

We present the most sensitive and detailed view of the neutral hydrogen ( ${\rm H\small I}$ ) emission associated with the Small Magellanic Cloud (SMC), through the combination of data from the Australian Square Kilometre Array Pathfinder (ASKAP) and Parkes (Murriyang), as part of the Galactic Australian Square Kilometre Array Pathfinder (GASKAP) pilot survey. These GASKAP-HI pilot observations, for the first time, reveal ${\rm H\small I}$ in the SMC on similar physical scales as other important tracers of the interstellar medium, such as molecular gas and dust. The resultant image cube possesses an rms noise level of 1.1 K ( $1.6\,\mathrm{mJy\ beam}^{-1}$ ) $\mathrm{per}\ 0.98\,\mathrm{km\ s}^{-1}$ spectral channel with an angular resolution of $30^{\prime\prime}$ ( ${\sim}10\,\mathrm{pc}$ ). We discuss the calibration scheme and the custom imaging pipeline that utilises a joint deconvolution approach, efficiently distributed across a computing cluster, to accurately recover the emission extending across the entire ${\sim}25\,\mathrm{deg}^2$ field-of-view. We provide an overview of the data products and characterise several aspects including the noise properties as a function of angular resolution and the represented spatial scales by deriving the global transfer function over the full spectral range. A preliminary spatial power spectrum analysis on individual spectral channels reveals that the power law nature of the density distribution extends down to scales of 10 pc. We highlight the scientific potential of these data by comparing the properties of an outflowing high-velocity cloud with previous ASKAP+Parkes ${\rm H\small I}$ test observations.

Objectives: Prior research has identified numerous genetic (including sex), education, health, and lifestyle factors that predict cognitive decline. Traditional model selection approaches (e.g., backward or stepwise selection) attempt to find one model that best fits the observed data, risking interpretations that only the selected predictors are important. In reality, several predictor combinations may fit similarly well but result in different conclusions (e.g., about size and significance of parameter estimates). In this study, we describe an alternative method, Information-Theoretic (IT) model averaging, and apply it to characterize a set of complex interactions in a longitudinal study on cognitive decline. Methods: Here, we used longitudinal cognitive data from 1256 late–middle aged adults from the Wisconsin Registry for Alzheimer’s Prevention study to examine the effects of sex, apolipoprotein E (APOE) ɛ4 allele (non-modifiable factors), and literacy achievement (modifiable) on cognitive decline. For each outcome, we applied IT model averaging to a set of models with different combinations of interactions among sex, APOE, literacy, and age. Results: For a list-learning test, model-averaged results showed better performance for women versus men, with faster decline among men; increased literacy was associated with better performance, particularly among men. APOE had less of an association with cognitive performance in this age range (∼40–70 years). Conclusions: These results illustrate the utility of the IT approach and point to literacy as a potential modifier of cognitive decline. Whether the protective effect of literacy is due to educational attainment or intrinsic verbal intellectual ability is the topic of ongoing work. (JINS, 2019, 25, 119–133)

Objectives: A major challenge in cognitive aging is differentiating preclinical disease-related cognitive decline from changes associated with normal aging. Neuropsychological test authors typically publish single time-point norms, referred to here as unconditional reference values. However, detecting significant change requires longitudinal, or conditional reference values, created by modeling cognition as a function of prior performance. Our objectives were to create, depict, and examine preliminary validity of unconditional and conditional reference values for ages 40–75 years on neuropsychological tests. Method: We used quantile regression to create growth-curve–like models of performance on tests of memory and executive function using participants from the Wisconsin Registry for Alzheimer’s Prevention. Unconditional and conditional models accounted for age, sex, education, and verbal ability/literacy; conditional models also included past performance on and number of prior exposures to the test. Models were then used to estimate individuals’ unconditional and conditional percentile ranks for each test. We examined how low performance on each test (operationalized as <7th percentile) related to consensus-conference–determined cognitive statuses and subjective impairment. Results: Participants with low performance were more likely to receive an abnormal cognitive diagnosis at the current visit (but not later visits). Low performance was also linked to subjective and informant reports of worsening memory function. Conclusions: The percentile-based methods and single-test results described here show potential for detecting troublesome within-person cognitive change. Development of reference values for additional cognitive measures, investigation of alternative thresholds for abnormality (including multi-test criteria), and validation in samples with more clinical endpoints are needed. (JINS, 2019, 25, 1–14)

OBJECTIVES/SPECIFIC AIMS: This study will use face-to-face interviewers with Medicare-eligible stroke survivors, and adult caregivers of stroke survivors, to extend the aims of a quantitative study on healthcare utilization in elderly stroke survivors. The objective of this research is to better understand, in more detail, relevant barriers and facilitators to accessing healthcare among older stroke survivors. The ultimate goal of this research is to develop strategies to improve access to healthcare, such as home modifications; changes to the neighborhood physical environment; or interventions at the provider/service level. This research will also serve as a precursor for future intervention work that will be proposed as a part of a K01 proposal. METHODS/STUDY POPULATION: Participants were recruited from Ann Arbor and Flint, MI using an existing academic-community partnership as well as through the University of Michigan Stroke Clinic. A total of 8–10 stroke survivors and 1–2 caregivers were recruited through the partnership and clinic records, as well as some use of snowball sampling to obtain a socially, economically, and racially representative sample. Participants must be 65+ years old, eligible for Medicare, living in the community, identify as either White or Black, and have no major cognitive/language deficits that jeopardize informed consent. Face-to-face interviews were conducted, and open-ended questions emphasized environmental barriers and facilitators to accessing healthcare, with a focus on social and physical barriers in the home and neighborhood. Interviews were audio recorded and transcribed, and field notes from 1 to 2 sources were also documented and will be used to triangulate the data and increase coding validity. Audio recordings will be reviewed multiple times and quotes relevant to the research questions and underlying theoretical framework will be transcribed verbatim. The transcripts will be analyzed using thematic coding based on literature and the study objectives and hypotheses. I will identify primary themes related to environmental barriers and facilitators to accessing healthcare among the stroke-survivors. RESULTS/ANTICIPATED RESULTS: Preliminary results suggest that participants are primarily concerned about the social environment. Several interviews revealed that stroke survivors felt socially isolated and were often hesitant to ask for help because they did not want to be a burden on their family and friends. Transportation to appointments was also identified as a barrier due to the fact that many people are no longer able to drive, yet are not comfortable navigating other forms of transportation. We expect to identify additional physical and social environmental challenges to both health care utilization and well-being more generally, among older stroke survivors. Anticipated themes may include: barriers in the physical environment such as transportation to care and services, social support and social environmental factors to support feeling safe leaving home to access care. DISCUSSION/SIGNIFICANCE OF IMPACT: Despite the physical and economic burden of stroke, and attempts to improve outcomes for stroke survivors living in the community, stroke survivors have high rates of disability and unmet medical and psychological needs. The results from this research are anticipated to directly inform future partnerships and intervention in these, or in similar communities. Understanding how the environment influences access to healthcare for elderly stroke survivors is essential if we want to increase recommended preventative care and treatment in this vulnerable population with unique healthcare needs. The results of this study will be used to directly inform the aims and methods for other translational research projects, including a K01 proposal, in which I will develop and pilot a community-based intervention to ameliorate environmental barriers and enhance facilitators of access to healthcare for older, disabled adults.

Antarctic and Southern Ocean science is vital to understanding natural variability, the processes that govern global change and the role of humans in the Earth and climate system. The potential for new knowledge to be gained from future Antarctic science is substantial. Therefore, the international Antarctic community came together to ‘scan the horizon’ to identify the highest priority scientific questions that researchers should aspire to answer in the next two decades and beyond. Wide consultation was a fundamental principle for the development of a collective, international view of the most important future directions in Antarctic science. From the many possibilities, the horizon scan identified 80 key scientific questions through structured debate, discussion, revision and voting. Questions were clustered into seven topics: i) Antarctic atmosphere and global connections, ii) Southern Ocean and sea ice in a warming world, iii) ice sheet and sea level, iv) the dynamic Earth, v) life on the precipice, vi) near-Earth space and beyond, and vii) human presence in Antarctica. Answering the questions identified by the horizon scan will require innovative experimental designs, novel applications of technology, invention of next-generation field and laboratory approaches, and expanded observing systems and networks. Unbiased, non-contaminating procedures will be required to retrieve the requisite air, biota, sediment, rock, ice and water samples. Sustained year-round access to Antarctica and the Southern Ocean will be essential to increase winter-time measurements. Improved models are needed that represent Antarctica and the Southern Ocean in the Earth System, and provide predictions at spatial and temporal resolutions useful for decision making. A co-ordinated portfolio of cross-disciplinary science, based on new models of international collaboration, will be essential as no scientist, programme or nation can realize these aspirations alone.

The purpose of the current paper was to conduct a systematic review of the literature on predictors of emotional distress in caregivers of persons with traumatic brain injury (TBI), and to provide evidence-based classification for prognostic variables to guide future research and clinical practice. A search was conducted using PubMed, CINAHL and PsycINFO databases. The citations of resulting articles were also reviewed. Twenty-eight articles met inclusion criteria and were retained for review. Reviews were conducted in accordance with the 2011 edition of the American Academy of Neurology (AAN) Guidelines for classifying evidence for prognostic studies. Data abstraction revealed one Class I study, four Class II studies, eight Class III studies, and 15 Class IV studies. Results of the review indicated that caregivers’ report of neurobehavioural problems in the person with injury is a probable predictor of emotional distress for caregivers of persons with complicated mild, moderate or severe TBI (Class B evidence). The level of participation in the person with injury, level of support needed by the person with injury, and family systems functioning are probably predictors of emotional distress for caregivers of persons with severe TBI (Class B evidence). Executive functioning impairment in the person with injury, pre-injury emotional distress in caregivers, caregiver age, caregivers’ use of emotion-focused coping, and social support may possibly be risk factors for caregivers’ emotional distress (Class C evidence). Recommendations for future research and implications for assessment and treatment of family caregivers are discussed.

As mice recover from infection with Babesia microti, abnormal forms of the parasite are present in some red cells. These forms are non-infective, indistinguishable by light microscopy from those present after treatment with amicarbalide, a babesicidal drug, and persist in splenectomized mice.

Electron microscopy confirmed that these abnormal forms are degenerating intra-erythrocytic parasites. In the absence of evidence for death of B. microti elsewhere in the body, it appears that infections of mice with this parasite are normally terminated by their death within circulating red cells. This has important implications for the mechanism of immunity to both this parasite and those Plasmodium spp. with which it cross-protects in this host.

Previous research has associated the development of social phobia with parental rearing practices, learning influences such as conditioning, vicarious transmission and verbal acquisition, and the individual's own response to social situations. The present study aimed to further investigate these possible antecedents of social phobia. A Learning History Questionnaire (LHQ) was completed by patients with social phobia (n=55), patients with posttraumatic stress disorder (PTSD; n=30), and non-patient controls (n=30). The LHQ focused on events that occurred before the age of 14 (the median age of onset for social phobia). The results indicated the importance of parental rearing practices such as not actively encouraging participation in social situations and emotional coldness. Difficulties with peer group were highlighted as important contributors to conditioning experiences. Individual response factors, especially post-event rumination, are potentially associated with the development of social phobia. Four of the 12 significant variables were unique to the social phobia group when the results from the PTSD group were taken into account. Further research is required to clarify the extent to which the environmental factors assessed in this study specifically contribute to the development of social phobia or to the development of anxiety more generally.