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The Theory of Countable Borel Equivalence Relations
- Alexander S. Kechris
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- November 2024
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- 30 November 2024
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The theory of definable equivalence relations has been a vibrant area of research in descriptive set theory for the past three decades. It serves as a foundation of a theory of complexity of classification problems in mathematics and is further motivated by the study of group actions in a descriptive, topological, or measure-theoretic context. A key part of this theory is concerned with the structure of countable Borel equivalence relations. These are exactly the equivalence relations generated by Borel actions of countable discrete groups and this introduces important connections with group theory, dynamical systems, and operator algebras. This text surveys the state of the art in the theory of countable Borel equivalence relations and delineates its future directions and challenges. It gives beginning graduate students and researchers a bird's-eye view of the subject, with detailed references to the extensive literature provided for further study.
Alcohol milestones and internalizing, externalizing, and executive function: longitudinal and polygenic score associations
- Sarah E. Paul, David A.A. Baranger, Emma C. Johnson, Joshua J. Jackson, Aaron J. Gorelik, Alex P. Miller, Alexander S. Hatoum, Wesley K. Thompson, Michael Strube, Danielle M. Dick, Chella Kamarajan, John R. Kramer, Martin H. Plawecki, Grace Chan, Andrey P. Anokhin, David B. Chorlian, Sivan Kinreich, Jacquelyn L. Meyers, Bernice Porjesz, Howard J. Edenberg, Arpana Agrawal, Kathleen K. Bucholz, Ryan Bogdan
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- Psychological Medicine , First View
- Published online by Cambridge University Press:
- 09 May 2024, pp. 1-14
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Background
Although the link between alcohol involvement and behavioral phenotypes (e.g. impulsivity, negative affect, executive function [EF]) is well-established, the directionality of these associations, specificity to stages of alcohol involvement, and extent of shared genetic liability remain unclear. We estimate longitudinal associations between transitions among alcohol milestones, behavioral phenotypes, and indices of genetic risk.
MethodsData came from the Collaborative Study on the Genetics of Alcoholism (n = 3681; ages 11–36). Alcohol transitions (first: drink, intoxication, alcohol use disorder [AUD] symptom, AUD diagnosis), internalizing, and externalizing phenotypes came from the Semi-Structured Assessment for the Genetics of Alcoholism. EF was measured with the Tower of London and Visual Span Tasks. Polygenic scores (PGS) were computed for alcohol-related and behavioral phenotypes. Cox models estimated associations among PGS, behavior, and alcohol milestones.
ResultsExternalizing phenotypes (e.g. conduct disorder symptoms) were associated with future initiation and drinking problems (hazard ratio (HR)⩾1.16). Internalizing (e.g. social anxiety) was associated with hazards for progression from first drink to severe AUD (HR⩾1.55). Initiation and AUD were associated with increased hazards for later depressive symptoms and suicidal ideation (HR⩾1.38), and initiation was associated with increased hazards for future conduct symptoms (HR = 1.60). EF was not associated with alcohol transitions. Drinks per week PGS was linked with increased hazards for alcohol transitions (HR⩾1.06). Problematic alcohol use PGS increased hazards for suicidal ideation (HR = 1.20).
ConclusionsBehavioral markers of addiction vulnerability precede and follow alcohol transitions, highlighting dynamic, bidirectional relationships between behavior and emerging addiction.
Insights into feeding preterm infants in Aotearoa, New Zealand: a mixed-method study
- S. Cooper, M. Muelbert, T. Alexander
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- Proceedings of the Nutrition Society / Volume 83 / Issue OCE1 / April 2024
- Published online by Cambridge University Press:
- 07 May 2024, E87
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Optimal nutrition is essential for preterm infants as they face many barriers to achieving exclusive breastfeeding (EBF) and successfully introducing complementary foods (CF)(1). There is limited evidence of early feeding practices of preterm infants in Aotearoa, New Zealand (NZ). We aimed to investigate the facilitators and barriers to EBF and CF introduction in preterm infants in NZ. A nationwide self-completed electronic questionnaire was disseminated via social media to mothers of preterm infants. The survey collected quantitative data on hospital feeding practices, breastfeeding rates, timing of CF introduction, and fussy eating behaviours. Relationships between feeding practices and maternal and infant characteristics, such as ethnicity and level of prematurity, were explored using the Chi-Square statistical test in SPSS. Qualitative information regarding mothers’ experiences with breastfeeding, CF introduction, type of education and support received about the nutrition of preterm infants were collected for thematic analysis using Nvivo. The survey started in April and will close on 20th August 2023. Here we present preliminary findings of a subset of responses collected to date, and full results will be available for the conference. Up to 1st August 2023, 201 mothers had completed the survey. Most mothers self-identified as of New Zealand European (58%) and Māori (13%) background. Most infants (39%) were older than 12 months of chronological age (CA) and born moderate or late preterm (32+0 – 36+6 weeks’ gestation, 70%). Almost 50% of mothers required in-hospital supplementation of mothers’ milk (infant formula, 28% and donor breastmilk, 20%), and 44% of mothers were EBF at the time of hospital discharge. EBF for 5-6 months of CA was reported by 21% of mothers, and 46% provided any breastmilk for more than 6 months of CA. Among mothers who had introduced CF (n = 138), 74% reported introducing CF between 5-8 months of CA, and the infant’s first foods were primarily vegetables (65%) and fruits (60%). Fussy eating behaviour was reported by 47%, and food fussiness was significantly associated with a decreased frequency of vegetable (p<0.001) and fruit (p = 0.004) consumption. Challenges with breastfeeding included the infant’s feeding difficulties, low milk supply, maternal stressors, lack of support and education from health professionals. Challenges to CF introduction included fussiness and maternal fears such as choking and lack of confidence. Support from lactation consultants and previous experience with introducing CF were the most common enablers for breastfeeding and timely CF introduction, respectively. Our findings provide the first insight into the early feeding practices of preterm infants in Aotearoa, New Zealand. This information will support strategies to improve the nutritional management of preterm infants by increasing awareness of common challenges mothers face to achieve the recommended breastfeeding guidelines and CF practices in this vulnerable population.
Environmental risk factors for schizophrenia and bipolar disorder from childhood to diagnosis: a Swedish nested case–control study
- Natassia Robinson, Alexander Ploner, Marica Leone, Paul Lichtenstein, Kenneth S. Kendler, Sarah E. Bergen
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- Psychological Medicine , First View
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- 01 March 2024, pp. 1-10
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Background:
Shared genetic risk between schizophrenia (SCZ) and bipolar disorder (BD) is well-established, yet the extent to which they share environmental risk factors remains unclear. We compare the associations between environmental exposures during childhood/prior to disorder onset with the risk of developing SCZ and BD.
Methods:We conducted a Swedish register-based nested case–control study using 4184 SCZ cases and 18 681 BD cases diagnosed 1988–2013. Cases were matched to five controls by birth year, birth region, and sex. Conditional logistic regression was used to estimate incidence rate ratios (IRR) for SCZ and BD for each exposure (severe childhood infections, adverse childhood experiences (ACEs), substance use disorders (SUDs), urban birth/longest residence).
Results:All SUD types were associated with very high risk (IRR 4.9–25.5), and all forms of ACEs with higher risk (IRR 1.5–4.3) for both disorders. In the mutually adjusted models, ACEs demonstrated slightly higher risk for BD (SCZ IRR 1.30, 1.19-1.42; BD IRR 1.49, 1.44–1.55), while for SUD, risk was higher for SCZ (SCZ IRR 9.43, 8.15–10.92; BD IRR 5.50, 5.15–5.88). Infections were associated with increased risk of BD (IRR 1.21, 1.17–1.26) but not SCZ. Urban birth and urban longest residence were associated with higher risk of SCZ (IRR 1.19, 1.03–1.37), while only the combination of urban birth and rural longest residence showed higher risk for BD (IRR 1.24, 1.13–1.35).
Conclusions:There were both shared and unique environmental risk factors: SUDs and ACEs were risk factors for both disorders, while infections were more strongly associated with BD and urbanicity with SCZ.
Comparing local energy cascade rates in isotropic turbulence using structure-function and filtering formulations
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- Hanxun Yao, Michael Schnaubelt, Alexander S. Szalay, Tamer A. Zaki, Charles Meneveau
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- Journal of Fluid Mechanics / Volume 980 / 10 February 2024
- Published online by Cambridge University Press:
- 06 February 2024, A42
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Two common definitions of the spatially local rate of kinetic energy cascade at some scale $\ell$ in turbulent flows are (i) the cubic velocity difference term appearing in the ‘scale-integrated local Kolmogorov–Hill’ equation (structure-function approach), and (ii) the subfilter-scale energy flux term in the transport equation for subgrid-scale kinetic energy (filtering approach). We perform a comparative study of both quantities based on direct numerical simulation data of isotropic turbulence at Taylor-scale Reynolds number 1250. While in the past observations of negative subfilter-scale energy flux (backscatter) have led to debates regarding interpretation and relevance of such observations, we argue that the interpretation of the local structure-function-based cascade rate definition is unambiguous since it arises from a divergence term in scale space. Conditional averaging is used to explore the relationship between the local cascade rate and the local filtered viscous dissipation rate as well as filtered velocity gradient tensor properties such as its invariants. We find statistically robust evidence of inverse cascade when both the large-scale rotation rate is strong and the large-scale strain rate is weak. Even stronger net inverse cascading is observed in the ‘vortex compression’ $R>0$, $Q>0$ quadrant, where $R$ and $Q$ are velocity gradient invariants. Qualitatively similar but quantitatively much weaker trends are observed for the conditionally averaged subfilter-scale energy flux. Flow visualizations show consistent trends, namely that spatially, the inverse cascade events appear to be located within large-scale vortices, specifically in subregions when $R$ is large.
Social connections and risk of incident mild cognitive impairment, dementia, and mortality in 13 longitudinal cohort studies of ageing
- Gowsaly Mahalingam, Suraj Samtani, Ben Chun Pan Lam, Darren M Lipnicki, Maria Fernanda Lima-Costa, Sergio Luis Blay, Erico Castro-Costa, Xiao Shifu, Maëlenn Guerchet, Pierre-Marie Preux, Antoine Gbessemehlan, Ingmar Skoog, Jenna Najar, Therese Rydberg Sterner, Nikolaos Scarmeas, Mary Yannakoulia, Themis Dardiotis, Ki-Woong Kim, Steffi Riedel-Heller, Susanne Röhr, Alexander Pabst, Suzana Shahar, Katya Numbers, Mary Ganguli, Tiffany F. Hughes, Ching-Chou H. Chang, Michael Crowe, Tze Pin Ng, Xinyi Gwee, Denise Qian Ling Chua, representatives from SHARED work packages, Joanna Rymaszewska, Karin Wolf-Ostermann, Anna-Karin Welmer, Jean Stafford, Myrra Vernooij-Dassen, Yun-Hee Jeon, Perminder S Sachdev, Henry Brodaty
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- International Psychogeriatrics / Volume 35 / Issue S1 / December 2023
- Published online by Cambridge University Press:
- 02 February 2024, pp. 16-17
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Background:
Good social connections are proposed to positively influence the course of cognitive decline by stimulating cognitive reserve and buffering harmful stress-related health effects. Prior meta-analytic research has uncovered links between social connections and the risk of poor health outcomes such as mild cognitive impairment, dementia, and mortality. These studies have primarily used aggregate data from North America and Europe with limited markers of social connections. Further research is required to explore these associations longitudinally across a wider range of social connection markers in a global setting.
Research Objective:We examined the associations between social connection structure, function, and quality and the risk of our primary outcomes (mild cognitive impairment, dementia, and mortality).
Method:Individual participant-level data were obtained from 13 longitudinal studies of ageing from across the globe. We conducted survival analysis using Cox regression models and combined estimates from each study using two-stage meta-analysis. We examined three social constructs: connection structure (living situation, relationship status, interactions with friends/family, community group engagement), function (social support, having a confidante) and quality (relationship satisfaction, loneliness) in relation to the risks of three primary outcomes (mild cognitive impairment, dementia, and mortality). In our partially adjusted models, we included age, sex, and education and in fully adjusted models used these variables as well as diabetes, hypertension, smoking, cardiovascular risk, and depression.
Preliminary results of the ongoing study:In our fully adjusted models we observed: a lower risk of mild cognitive impairment was associated with being married/in a relationship (vs. being single), weekly community group engagement (vs. no engagement), weekly family/friend interactions (vs. not interacting), and never feeling lonely (vs. often feeling lonely); a lower risk of dementia was associated with monthly/weekly family/friend interactions and having a confidante (vs. no confidante); a lower risk of mortality was associated with living with others (vs. living alone), yearly/monthly/weekly community group engagement, and having a confidante.
Conclusion:Good social connection structure, function, and quality are associated with reduced risk of incident MCI, dementia, and mortality. Our results provide actionable evidence that social connections are required for healthy ageing.
A decade of clinical microbiology: top 10 advances in 10 years: what every infection preventionist and antimicrobial steward should know
- Tulip A. Jhaveri, Zoe Freeman Weiss, Marisa L. Winkler, Alexander D. Pyden, Sankha S. Basu, Nicole D. Pecora
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- Antimicrobial Stewardship & Healthcare Epidemiology / Volume 4 / Issue 1 / 2024
- Published online by Cambridge University Press:
- 25 January 2024, e8
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The past 10 years have brought paradigm-shifting changes to clinical microbiology. This paper explores the top 10 transformative innovations across the diagnostic spectrum, including not only state of the art technologies but also preanalytic and post-analytic advances. Clinical decision support tools have reshaped testing practices, curbing unnecessary tests. Innovations like broad-range polymerase chain reaction and metagenomic sequencing, whole genome sequencing, multiplex molecular panels, rapid phenotypic susceptibility testing, and matrix-assisted laser desorption ionization time-of-flight mass spectrometry have all expanded our diagnostic armamentarium. Rapid home-based testing has made diagnostic testing more accessible than ever. Enhancements to clinician-laboratory interfaces allow for automated stewardship interventions and education. Laboratory restructuring and consolidation efforts are reshaping the field of microbiology, presenting both opportunities and challenges for the future of clinical microbiology laboratories. Here, we review key innovations of the last decade.
Martin Heidegger and Karl Löwith: Correspondence: 1919–1973. Translated by J. Goesser Assaiante and S. Montgomery Ewegen. (Lanham, MD: Rowman & Littlefield, 2021. Pp. xx, 314.)
- Alexander S. Duff
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- The Review of Politics / Volume 86 / Issue 2 / Spring 2024
- Published online by Cambridge University Press:
- 15 January 2024, pp. 273-276
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Lamellar nanostructure in ‘Somasif’-based organoclays
- Mikhail Y. Gelfer, Christian Burger, Pranav Nawani, Benjamin S. Hsiao, Benjamin Chu, Mayu Si, Miriam Rafailovich, Grazyna Panek, Gunnar Jeschke, Alexander Y. Fadeev, Jeffrey W. Gilman
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- Clays and Clay Minerals / Volume 55 / Issue 2 / April 2007
- Published online by Cambridge University Press:
- 01 January 2024, pp. 140-150
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Thermally induced lamellar structure changes due to phase transition and degradation in organoclays based on a synthetic ‘Somasif’ mineral and two organic surfactants, di-methyl dihydro-ditallow ammonia chloride (DMDTA) and tri-butyl-hexadecyl phosphonium bromide (HTBP) were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, in situ simultaneous small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) over the temperature range 30–280°C. Results indicated that the surfactant layer in ‘Somasif’-based organoclays underwent thermally induced melting-like order-disorder transition followed by desorption of surfactant molecules, resulting in drastic changes in the character of the layer periodicity. The transition temperature (Ttr), determined from the endothermic transition in DSC, was found to depend strongly on the type and the content of surfactant incorporated. Temperature-resolved SAXS indicated complex intercalated layered structures, containing multiple lamellar stack populations of two different organic layer thicknesses. A weak scattering peak (s0), located at exactly the half angular position of the strong first scattering maximum s1 (s0 = 0.5s1), was found in all tested ‘Somasif’ clays. The presence of this peak can be attributed to a slight breaking of the translational symmetry in the layered structure, causing the 1D repeat period in real space to be doubled. In other words, some portions of layers are grouped into pairs and a single pair forms the new repeat unit. This arrangement is reminiscent of the Peierls-like distortion.
2 Neurocognition and Functional Status Among Ethnoculturally Diverse Older Adults: Support for the External Validity of the ADAS-Cog
- Elizabeth A Breen, Jordan T Stiver, Micah J Savin, Denise S Oleas, Alexander W Slaughter, Maral Aghvinian, Heining Cham, Monica G Rivera Mindt
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 86-87
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Objective:
Alzheimer’s Disease (AD) and dementia present major and escalating public health concerns for the U.S., especially among ethnoculturally diverse (e.g., Latinx, non-Latinx Black [NLB]) populations who represent an increasing percentage of the older adult population in the US and bear greater AD burden compared to non-Latinx Whites (NLWs). Notably, neurocognition and functional status are highly correlated in those with AD. However, little has been done to understand these associations and validate functional measures across geographically diverse, multiethnic samples. The aims of this study were to characterize the neurocognition and functional status of a large, multiethnic sample and subsequently examine any associations between neurocognition and functional status among Latinx, NLB, and NLW older adults.
Participants and Methods:This cross-sectional, retrospective study utilized archival data drawn from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). ADNI is a national, longitudinal, multi-site, observational study aiming to measure the progression of AD (see https://adni-info.org). Study measures included the: 1) Alzheimer’s Disease Assessment Scale Cognitive subscale (ADAS-cog; 13-items), a global neurocognitive battery evaluating neurocognition in people with AD; 2) Functional Activities Questionnaire (FAQ; 10-item questionnaire) to assess functional status; 3) Geriatric Depression Scale (GDS; 15-item questionnaire) for depression; and 4) American National Adult Reading Test (ANART; 50-word test) for reading level. The sample included 1537 older adults who completed baseline visits for the ADNI study, 1333 of whom were NLW, 123 NLB, and 81 Latinx. The average age of the sample was 73 years, average 16 years of education, and 53% male. Compared to the NLW group, the NLB and Latinx groups were significantly younger and had a higher percentage of female participants. Compared to NLW and Latinx groups, the NLB group also had significantly fewer years of education and lower reading scores. Potential confounds (i.e., demographic variables, depression) were identified a priori based on the literature and subsequently analyzed for inclusion as covariates in the primary analyses. Analyses revealed variables were non-normally distributed, therefore Independent Samples Kruskal-Wallis tests and Spearman’s Correlations were computed to examine differences and correlations between ethnocultural groups.
Results:After controlling for age and education, Latinx and NLB groups had significantly higher ADAS-cog and FAQ scores than the NLW group (Hs = 9.50-21.53, ps < .05). Spearman’s partial correlations controlling for age, education, gender, and depression revealed that higher ADAS-cog scores were associated with higher FAQ scores within Latinx (p=.49, p<.001), NLB (p=.66, p<.001), and NLW (p=.60, p<.001) groups.
Conclusions:Findings indicate that neurocognition is positively associated with functional status and support the ecological and external validity of the ADAS-cog and FAQ for use with NLB and Latinx older adults, in addition to previously established work with more homogenous samples. Study strengths include the overall sample size, geographic diversity, and standardization of research approaches. Study limitations include high education level and low comorbidity rates present in the sample, limiting the generalizability of the results, in addition to the unbalanced ethnocultural groups, further emphasizing the need for increased inclusion efforts of ethnoculturally diverse older adults into brain health research studies.
61 Network Segregation Predicts Processing Speed in the Cognitively Healthy Oldest-old
- Sara A Nolin, Mary E Faulkner, Paul Stewart, Leland Fleming, Stacy Merritt, Roxanne F Rezaei, Pradyumna K Bharadwaj, Mary Kathryn Franchetti, Daniel A Raichlen, Courtney J Jessup, Lloyd Edwards, G Alex Hishaw, Emily J Van Etten, Theodore P Trouard, David S Geldmacher, Virginia G Wadley, Noam Alperin, Eric C Porges, Adam J Woods, Ronald A Cohen, Bonnie E Levin, Tatjana Rundek, Gene E Alexander, Kristina M Visscher
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- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 367-368
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Objective:
Understanding the factors contributing to optimal cognitive function throughout the aging process is essential to better understand successful cognitive aging. Processing speed is an age sensitive cognitive domain that usually declines early in the aging process; however, this cognitive skill is essential for other cognitive tasks and everyday functioning. Evaluating brain network interactions in cognitively healthy older adults can help us understand how brain characteristics variations affect cognitive functioning. Functional connections among groups of brain areas give insight into the brain’s organization, and the cognitive effects of aging may relate to this large-scale organization. To follow-up on our prior work, we sought to replicate our findings regarding network segregation’s relationship with processing speed. In order to address possible influences of node location or network membership we replicated the analysis across 4 different node sets.
Participants and Methods:Data were acquired as part of a multi-center study of 85+ cognitively normal individuals, the McKnight Brain Aging Registry (MBAR). For this analysis, we included 146 community-dwelling, cognitively unimpaired older adults, ages 85-99, who had undergone structural and BOLD resting state MRI scans and a battery of neuropsychological tests. Exploratory factor analysis identified the processing speed factor of interest. We preprocessed BOLD scans using fmriprep, Ciftify, and XCPEngine algorithms. We used 4 different sets of connectivity-based parcellation: 1)MBAR data used to define nodes and Power (2011) atlas used to determine node network membership, 2) Younger adults data used to define nodes (Chan 2014) and Power (2011) atlas used to determine node network membership, 3) Older adults data from a different study (Han 2018) used to define nodes and Power (2011) atlas used to determine node network membership, and 4) MBAR data used to define nodes and MBAR data based community detection used to determine node network membership.
Segregation (balance of within-network and between-network connections) was measured within the association system and three wellcharacterized networks: Default Mode Network (DMN), Cingulo-Opercular Network (CON), and Fronto-Parietal Network (FPN). Correlation between processing speed and association system and networks was performed for all 4 node sets.
Results:We replicated prior work and found the segregation of both the cortical association system, the segregation of FPN and DMN had a consistent relationship with processing speed across all node sets (association system range of correlations: r=.294 to .342, FPN: r=.254 to .272, DMN: r=.263 to .273). Additionally, compared to parcellations created with older adults, the parcellation created based on younger individuals showed attenuated and less robust findings as those with older adults (association system r=.263, FPN r=.255, DMN r=.263).
Conclusions:This study shows that network segregation of the oldest-old brain is closely linked with processing speed and this relationship is replicable across different node sets created with varied datasets. This work adds to the growing body of knowledge about age-related dedifferentiation by demonstrating replicability and consistency of the finding that as essential cognitive skill, processing speed, is associated with differentiated functional networks even in very old individuals experiencing successful cognitive aging.
12 Do the Cognitive Effects of the Immigrant Health Paradox Vary Across the Lifespan?
- Denise S Oleas, Micah J Savin, Jordan Stiver, Maral N. Aghvinian, Alexander Slaughter, Elizabeth A. Breen, Heining Cham, Sandra Talavera, Desiree Byrd, Jessica Robinson Papp, Monica Rivera Mindt
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 427-428
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Objective:
The Immigrant Health Paradox (IHP) suggests that immigrants have better health upon arrival in comparison to their U.S.-born Latinx counterparts, indicating that immigrants’ unique experiences may buffer against negative health outcomes, including cognition. Some studies indicate that IHP-related cognitive health benefits diminish with increased time spent in the U.S., while others suggest that this relationship may be age-dependent such that compared to migration during earlier or later life, migration during young/middle adulthood may be related to better cognition-potentially due to higher simultaneous cognitive demands associated with this age epoch (e.g., language acquisition, acculturation). However, this literature is equivocal and has methodological limitations (e.g., cognition typically assessed with cognitive screeners, lack of clinical populations) Thus, this study aimed to examine the role of age related to IHP and cognition within a well-characterized sample of HIV+ Latinx adults. It was hypothesized that compared to U.S.-born Latinx adults and those who immigrated earlier or later in life, the Latinx immigrant subgroup who migrated during young/middle adulthood would demonstrate better cognitive functioning.
Participants and Methods:This cross-sectional study included a HIV+ sample (A/=105) of 34 Latinx immigrants (Mage=45.56, SD=6.99) and 71 U.S.-born Latinx individuals (Mage=46.03, SD=7.63), who completed a comprehensive sociocultural questionnaire and cognitive battery. Demographically-adjusted average T-scores were computed for each cognitive test and domain (e.g., learning, memory). A series of Welch’s-corrected ANOVAS with post hoc Games-Howell tests for multiple comparisons were conducted to compare cognitive function across three groups: Latinx immigrants who migrated during earlier (<19 yrs) or later adulthood (>50 yrs), young/middle adulthood (20-49 yrs), and U.S.-born Latinx adults.
Results:Compared to the other Latinx subgroups, Latinx immigrants who migrated during middle adulthood performed worse in Verbal Fluency (F(2,98)=8.04, p<.001), Attention/Working Memory (f(2,96)=6.10, p<.01), Executive Function (f(2,99)=5.11, p<.01), and Processing Speed (F(2,101)=3.36, p<.05). Posthoc Games-Howell tests showed that the mean Verbal Fluency (p<.01, 95% C.I.=[-21.37, -2.66]), Attention/Working Memory (p<.05, 95% C.I.=[-16.82, -1.59]), Executive Function (p<.01, 95% C.I.=[-14.66, -2.49]) and Processing Speed (p<.05, 95% C.I.=[-13.60, -1.31]) T-scores were significantly lower in Latinx immigrants who migrated in young/middle adulthood compared to the U.S.-born Latinx sample. Further, there were no differences between the U.S.-born Latinx group compared to the Latinx immigrant group who migrated earlier or later in life (ps>.05).
Conclusions:This preliminary study is the first to examine whether the potential protective cognitive effects of the IHP vary across the lifespan among Latinx immigrants with HIV, using a comprehensive neuropsychological battery. Age-related IHP benefits were not observed in this study. Moreover, Latinx immigrants who migrated during young/middle adulthood had worse cognitive functioning compared to their U.S.-born Latinx counterparts and those that migrated earlier or later in life. A possible explanation for this study’s unexpected findings is that the IHP is outdated due to the current sociopolitical climate immigrants experience compared to the 1980s when the theory was developed. Future studies, with larger samples, longitudinal designs, and greater sociocultural characterization (e.g., immigration reason/s, country of origin, discrimination), are needed to better understand the role of IHP in cognition.
2 Higher White Matter Hyperintensity Load Adversely Affects Pre-Post Proximal Cognitive Training Performance in Healthy Older Adults
- Emanuel M Boutzoukas, Andrew O’Shea, Jessica N Kraft, Cheshire Hardcastle, Nicole D Evangelista, Hanna K Hausman, Alejandro Albizu, Emily J Van Etten, Pradyumna K Bharadwaj, Samantha G Smith, Hyun Song, Eric C Porges, Alex Hishaw, Steven T DeKosky, Samuel S Wu, Michael Marsiske, Gene E Alexander, Ronald Cohen, Adam J Woods
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- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 671-672
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Objective:
Cognitive training has shown promise for improving cognition in older adults. Aging involves a variety of neuroanatomical changes that may affect response to cognitive training. White matter hyperintensities (WMH) are one common age-related brain change, as evidenced by T2-weighted and Fluid Attenuated Inversion Recovery (FLAIR) MRI. WMH are associated with older age, suggestive of cerebral small vessel disease, and reflect decreased white matter integrity. Higher WMH load associates with reduced threshold for clinical expression of cognitive impairment and dementia. The effects of WMH on response to cognitive training interventions are relatively unknown. The current study assessed (a) proximal cognitive training performance following a 3-month randomized control trial and (b) the contribution of baseline whole-brain WMH load, defined as total lesion volume (TLV), on pre-post proximal training change.
Participants and Methods:Sixty-two healthy older adults ages 65-84 completed either adaptive cognitive training (CT; n=31) or educational training control (ET; n=31) interventions. Participants assigned to CT completed 20 hours of attention/processing speed training and 20 hours of working memory training delivered through commercially-available Posit Science BrainHQ. ET participants completed 40 hours of educational videos. All participants also underwent sham or active transcranial direct current stimulation (tDCS) as an adjunctive intervention, although not a variable of interest in the current study. Multimodal MRI scans were acquired during the baseline visit. T1- and T2-weighted FLAIR images were processed using the Lesion Segmentation Tool (LST) for SPM12. The Lesion Prediction Algorithm of LST automatically segmented brain tissue and calculated lesion maps. A lesion threshold of 0.30 was applied to calculate TLV. A log transformation was applied to TLV to normalize the distribution of WMH. Repeated-measures analysis of covariance (RM-ANCOVA) assessed pre/post change in proximal composite (Total Training Composite) and sub-composite (Processing Speed Training Composite, Working Memory Training Composite) measures in the CT group compared to their ET counterparts, controlling for age, sex, years of education and tDCS group. Linear regression assessed the effect of TLV on post-intervention proximal composite and sub-composite, controlling for baseline performance, intervention assignment, age, sex, years of education, multisite scanner differences, estimated total intracranial volume, and binarized cardiovascular disease risk.
Results:RM-ANCOVA revealed two-way group*time interactions such that those assigned cognitive training demonstrated greater improvement on proximal composite (Total Training Composite) and sub-composite (Processing Speed Training Composite, Working Memory Training Composite) measures compared to their ET counterparts. Multiple linear regression showed higher baseline TLV associated with lower pre-post change on Processing Speed Training sub-composite (ß = -0.19, p = 0.04) but not other composite measures.
Conclusions:These findings demonstrate the utility of cognitive training for improving postintervention proximal performance in older adults. Additionally, pre-post proximal processing speed training change appear to be particularly sensitive to white matter hyperintensity load versus working memory training change. These data suggest that TLV may serve as an important factor for consideration when planning processing speed-based cognitive training interventions for remediation of cognitive decline in older adults.
6 Adjunctive Transcranial Direct Current Stimulation and Cognitive Training Alters Default Mode and Frontoparietal Control Network Connectivity in Older Adults
- Hanna K Hausman, Jessica N Kraft, Cheshire Hardcastle, Nicole D Evangelista, Emanuel M Boutzoukas, Andrew O’Shea, Alejandro Albizu, Emily J Van Etten, Pradyumna K Bharadwaj, Hyun Song, Samantha G Smith, Eric S Porges, Georg A Hishaw, Samuel Wu, Steven DeKosky, Gene E Alexander, Michael Marsiske, Ronald A Cohen, Adam J Woods
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 675-676
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Objective:
Aging is associated with disruptions in functional connectivity within the default mode (DMN), frontoparietal control (FPCN), and cingulo-opercular (CON) resting-state networks. Greater within-network connectivity predicts better cognitive performance in older adults. Therefore, strengthening network connectivity, through targeted intervention strategies, may help prevent age-related cognitive decline or progression to dementia. Small studies have demonstrated synergistic effects of combining transcranial direct current stimulation (tDCS) and cognitive training (CT) on strengthening network connectivity; however, this association has yet to be rigorously tested on a large scale. The current study leverages longitudinal data from the first-ever Phase III clinical trial for tDCS to examine the efficacy of an adjunctive tDCS and CT intervention on modulating network connectivity in older adults.
Participants and Methods:This sample included 209 older adults (mean age = 71.6) from the Augmenting Cognitive Training in Older Adults multisite trial. Participants completed 40 hours of CT over 12 weeks, which included 8 attention, processing speed, and working memory tasks. Participants were randomized into active or sham stimulation groups, and tDCS was administered during CT daily for two weeks then weekly for 10 weeks. For both stimulation groups, two electrodes in saline-soaked 5x7 cm2 sponges were placed at F3 (cathode) and F4 (anode) using the 10-20 measurement system. The active group received 2mA of current for 20 minutes. The sham group received 2mA for 30 seconds, then no current for the remaining 20 minutes.
Participants underwent resting-state fMRI at baseline and post-intervention. CONN toolbox was used to preprocess imaging data and conduct region of interest (ROI-ROI) connectivity analyses. The Artifact Detection Toolbox, using intermediate settings, identified outlier volumes. Two participants were excluded for having greater than 50% of volumes flagged as outliers. ROI-ROI analyses modeled the interaction between tDCS group (active versus sham) and occasion (baseline connectivity versus postintervention connectivity) for the DMN, FPCN, and CON controlling for age, sex, education, site, and adherence.
Results:Compared to sham, the active group demonstrated ROI-ROI increases in functional connectivity within the DMN following intervention (left temporal to right temporal [T(202) = 2.78, pFDR < 0.05] and left temporal to right dorsal medial prefrontal cortex [T(202) = 2.74, pFDR < 0.05]. In contrast, compared to sham, the active group demonstrated ROI-ROI decreases in functional connectivity within the FPCN following intervention (left dorsal prefrontal cortex to left temporal [T(202) = -2.96, pFDR < 0.05] and left dorsal prefrontal cortex to left lateral prefrontal cortex [T(202) = -2.77, pFDR < 0.05]). There were no significant interactions detected for CON regions.
Conclusions:These findings (a) demonstrate the feasibility of modulating network connectivity using tDCS and CT and (b) provide important information regarding the pattern of connectivity changes occurring at these intervention parameters in older adults. Importantly, the active stimulation group showed increases in connectivity within the DMN (a network particularly vulnerable to aging and implicated in Alzheimer’s disease) but decreases in connectivity between left frontal and temporal FPCN regions. Future analyses from this trial will evaluate the association between these changes in connectivity and cognitive performance post-intervention and at a one-year timepoint.
2 The Role of Causality in Understanding How Prior Event Knowledge Impacts New Learning
- Alexa S. Gonzalez, Anna B. Drummey, Tyler J. Hubeny, Alexander Held, Irene P. Kan
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 522-523
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Objective:
The influence of prior knowledge on new learning is well established. However, there has been less research dedicated to teasing apart the key components of prior knowledge’s structure that contribute to memory enhancement. In the current study, we focused on event structures, which include various relations, such as associative, causal, and temporal. Given that events possess attributes relevant to numerous cognitive memory processes, we were most interested in exploring how event structures that possess causal relations enhance new memory formation. Specifically, we examined whether events that exhibit causal associative relations provide an additional boost to new learning compared to event structures with non-causal associative relations.
Participants and Methods:Forty-six undergraduate students took part in the study. Participants’ learning of the content of image pairs that exhibit everyday, real-world events were measured using a cued recall paradigm. The stimuli consisted of 60 image pairs that illustrated two events that were related causally and associatively (i.e., causal pairs); related only associatively (i.e., non-causal pairs); or not related at all (i.e., unrelated pairs). During an encoding phase, image pairs were presented one at a time, and after the presentation of each image pair, participants answered an encoding question that focused on the relationship between the two images. After the encoding phase and a short filler task, participants were shown a cue image (always the first picture from the pair) and were asked to provide a brief written description of the content of the second presented image from each pair. Also, as a manipulation check, we asked subjects to rate each image pair on causal direction and association strength after completion of the cued recall memory task.
Results:We found that, relative to unrelated pairs, events that possess associative relations (i.e., both causal and non-causal items) benefit learning of new information. In addition, causal relations provided an additional boost to new learning. Specifically, cued recall performance is best for causal pairs, followed by non-causal pairs and unrelated pairs. Moreover, causal direction ratings significantly predict overall itemlevel accuracy above and beyond general associative relations that exist in events. We also examined recall accuracy for specific content information within each event (i.e., agent, action, object) and found that causal relations uniquely contribute to recall performance of objects and actions.
Conclusions:Overall, the present study’s findings suggest that prior event knowledge structures possessing causal and non-causal associative relations support new learning, especially compared to image pairs with no relations. Of interest, causality provides an additional boost to new learning above and beyond general associative relations. By focusing on the role of causality in event structures, our findings informed our understanding of how prior knowledge supports new learning. Considering that the effect of prior knowledge on new episodic learning is especially evident in older adults, since they more readily rely on their schematic knowledge, a future direction would entail investigating how causal links influence new memory formation in older adults.
9 Connecting memory and functional brain networks in older adults: a resting state fMRI study
- Jori L Waner, Hanna K Hausman, Jessica N Kraft, Cheshire Hardcastle, Nicole D Evangelista, Andrew O’Shea, Alejandro Albizu, Emanuel M Boutzoukas, Emily J Van Etten, Pradyumna K Bharadwaj, Hyun Song, Samantha G Smith, Steven T DeKosky, Georg A Hishaw, Samuel S Wu, Michael Marsiske, Ronald Cohen, Gene E Alexander, Eric C Porges, Adam J Woods
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 527-528
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Objective:
Nonpathological aging has been linked to decline in both verbal and visuospatial memory abilities in older adults. Disruptions in resting-state functional connectivity within well-characterized, higherorder cognitive brain networks have also been coupled with poorer memory functioning in healthy older adults and in older adults with dementia. However, there is a paucity of research on the association between higherorder functional connectivity and verbal and visuospatial memory performance in the older adult population. The current study examines the association between resting-state functional connectivity within the cingulo-opercular network (CON), frontoparietal control network (FPCN), and default mode network (DMN) and verbal and visuospatial learning and memory in a large sample of healthy older adults. We hypothesized that greater within-network CON and FPCN functional connectivity would be associated with better immediate verbal and visuospatial memory recall. Additionally, we predicted that within-network DMN functional connectivity would be associated with improvements in delayed verbal and visuospatial memory recall. This study helps to glean insight into whether within-network CON, FPCN, or DMN functional connectivity is associated with verbal and visuospatial memory abilities in later life.
Participants and Methods:330 healthy older adults between 65 and 89 years old (mean age = 71.6 ± 5.2) were recruited at the University of Florida (n = 222) and the University of Arizona (n = 108). Participants underwent resting-state fMRI and completed verbal memory (Hopkins Verbal Learning Test - Revised [HVLT-R]) and visuospatial memory (Brief Visuospatial Memory Test - Revised [BVMT-R]) measures. Immediate (total) and delayed recall scores on the HVLT-R and BVMT-R were calculated using each test manual’s scoring criteria. Learning ratios on the HVLT-R and BVMT-R were quantified by dividing the number of stimuli (verbal or visuospatial) learned between the first and third trials by the number of stimuli not recalled after the first learning trial. CONN Toolbox was used to extract average within-network connectivity values for CON, FPCN, and DMN. Hierarchical regressions were conducted, controlling for sex, race, ethnicity, years of education, number of invalid scans, and scanner site.
Results:Greater CON connectivity was significantly associated with better HVLT-R immediate (total) recall (ß = 0.16, p = 0.01), HVLT-R learning ratio (ß = 0.16, p = 0.01), BVMT-R immediate (total) recall (ß = 0.14, p = 0.02), and BVMT-R delayed recall performance (ß = 0.15, p = 0.01). Greater FPCN connectivity was associated with better BVMT-R learning ratio (ß = 0.13, p = 0.04). HVLT-R delayed recall performance was not associated with connectivity in any network, and DMN connectivity was not significantly related to any measure.
Conclusions:Connectivity within CON demonstrated a robust relationship with different components of memory function as well across verbal and visuospatial domains. In contrast, FPCN only evidenced a relationship with visuospatial learning, and DMN was not significantly associated with memory measures. These data suggest that CON may be a valuable target in longitudinal studies of age-related memory changes, but also a possible target in future non-invasive interventions to attenuate memory decline in older adults.
High-pressure metamorphism of Precambrian continental crust in the southwestern part of the Central Asian Orogenic Belt (South Kazakhstan and North Tien Shan) and tectonic implications for the evolution of the Palaeo-Asian Ocean
- Anfisa V. Skoblenko (Pilitsyna), Nadezhda A. Kanygina, Alexander S. Dubenskiy, Valentina G. Batanova, Yildirim Dilek, Victor S. Sheshukov, Pavel A. Serov
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- Journal:
- Geological Magazine / Volume 160 / Issue 8 / August 2023
- Published online by Cambridge University Press:
- 19 October 2023, pp. 1624-1648
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In this study, we investigated the high-pressure (HP) metamorphism of the Precambrian continental crust exposed in the Zheltau terrane in South Kazakhstan (Koyandy complex) and the Chu-Kendyktas terrane in the North Tien Shan of Kyrgyzstan (Aktyuz, Kemin and Kokdzhon complexes) within the SW part of the Central Asian Orogenic Belt. HP quartz–feldspar lithologies of the Koyandy complex consist of migmatized kyanite-bearing garnet–mica paragneisses, garnet–kyanite paragneisses and their derivatives associated with eclogites. Paragneisses demonstrate prograde evolution involving mica dehydration melting and producing magnesium-rich garnet, kyanite and K-feldspar at the near-peak to retrograde stages at pressures of 15–18.5 kbar and temperatures of 800–870°C. The widespread growth of micas in these rocks reflects lower stages of retrogression at P = 10–12 kbar and T = 720–770°C. The age distributions of the cores of detrital zircon grains from the paragneisses indicate a predominance of Neoproterozoic and minor occurrence of Mesoproterozoic and Palaeoproterozoic sources of their protoliths. The ages of ∼487–485 Ma obtained from the zircon rims of the paragneisses reflect the timing of their HP metamorphic re-equilibration. These age clusters are consistent with the age estimates obtained from the rims of zircons in the eclogite-bearing garnet gneisses of the adjacent Aktyuz complex in the North Tien Shan. The P–T paths and zircon ages obtained from the high-grade quartz–feldspar gneisses of the Zheltau and Chu-Kendyktas terranes are thus interpreted to indicate involvement of the crustal material derived from the Precambrian basement (magmatic zircons aged ca. 844 Ma) and its Ediacaran–Cambrian sedimentary cover (detrital zircons with maxima at 1 Ga and 800–600 Ma) in the latest Cambrian subduction processes induced by the closure of the oceanic basins assigned to the Palaeo-Asian Ocean.
Why Political Philosophy Should Be Robust
- ALEXANDER S. KIRSHNER, JEFF SPINNER-HALEV
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- American Political Science Review , First View
- Published online by Cambridge University Press:
- 16 October 2023, pp. 1-13
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Political philosophers and theorists make arguments about high-stakes problems. This article shows that those theories would be more credible if political philosophers ensured their work was robust: capable of withstanding reasonable changes to their assumptions and to the cases to which their arguments apply. The world is varied and inconstant. As a result, scientists and social scientists recognize the virtue of robustness. This article shows why political philosophers should also do so. It defines robustness, demonstrates its value, and shows how it can be evaluated. Illustrating the stakes of robustness, the article assesses prominent arguments concerning multiculturalism and open borders. Avoiding misunderstanding and confusion should be a central aim of political philosophy. To sidestep these outcomes and to reassure scholars that one’s theory is not subject to concerns about its credibility, it will often be reasonable for philosophers to explicitly test their theories for robustness.
Radiofrequency ice dielectric measurements at Summit Station, Greenland
- Juan Antonio Aguilar, Patrick Allison, Dave Besson, Abby Bishop, Olga Botner, Sjoerd Bouma, Stijn Buitink, Maddalena Cataldo, Brian A. Clark, Kenny Couberly, Zach Curtis-Ginsberg, Paramita Dasgupta, Simon de Kockere, Krijn D. de Vries, Cosmin Deaconu, Michael A. DuVernois, Anna Eimer, Christian Glaser, Allan Hallgren, Steffen Hallmann, Jordan Christian Hanson, Bryan Hendricks, Jakob Henrichs, Nils Heyer, Christian Hornhuber, Kaeli Hughes, Timo Karg, Albrecht Karle, John L. Kelley, Michael Korntheuer, Marek Kowalski, Ilya Kravchenko, Ryan Krebs, Robert Lahmann, Uzair Latif, Joseph Mammo, Matthew J. Marsee, Zachary S. Meyers, Kelli Michaels, Katharine Mulrey, Marco Muzio, Anna Nelles, Alexander Novikov, Alisa Nozdrina, Eric Oberla, Bob Oeyen, Ilse Plaisier, Noppadol Punsuebsay, Lilly Pyras, Dirk Ryckbosch, Olaf Scholten, David Seckel, Mohammad Ful Hossain Seikh, Daniel Smith, Jethro Stoffels, Daniel Southall, Karen Terveer, Simona Toscano, Delia Tosi, Dieder J. Van Den Broeck, Nick van Eijndhoven, Abigail G. Vieregg, Janna Z. Vischer, Christoph Welling, Dawn R. Williams, Stephanie Wissel, Robert Young, Adrian Zink
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- Journal of Glaciology , First View
- Published online by Cambridge University Press:
- 09 October 2023, pp. 1-12
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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.
RADIOCARBON DATING AND FRESHWATER RESERVOIR EFFECTS OF AQUATIC MOLLUSKS WITHIN FLUVIAL CHANNEL DEPOSITS IN THE MIDWESTERN UNITED STATES
- Jason A Rech, Christina N Tenison, Alexander Baldasare, Brian S Currie
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- Radiocarbon / Volume 65 / Issue 5 / October 2023
- Published online by Cambridge University Press:
- 28 November 2023, pp. 1098-1117
- Print publication:
- October 2023
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Late Quaternary fluvial channel deposits are notoriously difficult to date. In the midwestern United States, shells of aquatic mollusks can be found within many fluvial channel sediments and therefore can be radiocarbon (14C) dated to determine the age of the deposits. However, carbonate platform rocks are abundant in this region, potentially causing freshwater 14C reservoir effects (FRE) in mollusk shells. We 14C dated 11 aquatic gastropod and bivalve shell samples from specimens collected live from a stream in southwestern Ohio during three different years to assess the modern 14C reservoir effect. Modern samples yielded an average 14C FREmodern of 518 ± 65 14C yrs for 2020 (n=5), 640 ± 34 14C yrs for 2021 (n=2), and 707 ± 76 14C yrs for 2022 (n=4). We also 14C dated matched pairs of organic wood or charcoal and aquatic mollusk shells from late Pleistocene and Holocene deposits in the Four Mile Creek floodplain to determine the FREfossil. These samples, free of any potential influence from nuclear bomb testing, yielded an overall weighted mean FREfossil of 1029 ± 345 14C yrs. We then assess the advantages and limitations of both the FREmodern and FREfossil methods for determining freshwater reservoir effects. Finally, we apply the FREfossil correction to a series of shell ages from fluvial terrace deposits as a case study. The results indicate that although there is a 14C FRE in streams from the midwestern United States, aquatic shells can provide robust age control on fluvial channel deposits. More research is needed to understand the spatial and temporal variability of FREs, as well as any species effects, among various watersheds across the midwestern United States.