Showing papers by "University of New Mexico published in 2022"

Neurophysiology of Remembering.

Abstract: By linking the past with the future, our memories define our sense of identity. Because human memory engages the conscious realm, its examination has historically been approached from language and introspection and proceeded largely along separate parallel paths in humans and other animals. Here, we first highlight the achievements and limitations of this mind-based approach and make the case for a new brain-based understanding of declarative memory with a focus on hippocampal physiology. Next, we discuss the interleaved nature and common physiological mechanisms of navigation in real and mental spacetime. We suggest that a distinguishing feature of memory types is whether they subserve actions for single or multiple uses. Finally, in contrast to the persisting view of the mind as a highly plastic blank slate ready for the world to make its imprint, we hypothesize that neuronal networks are endowed with a reservoir of neural trajectories, and the challenge faced by the brain is how to select and match preexisting neuronal trajectories with events in the world. Expected final online publication date for the Annual Review of Psychology, Volume 73 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Suppression of fast neutrino flavor conversions occurring at large distances in core-collapse supernovae

Abstract: Abstract Neutrinos propagating in dense neutrino media such as core-collapse supernovae and neutron star merger remnants can experience the so-called fast flavor conversions on scales much shorter than those expected in vacuum. A very generic class of fast flavor instabilities is the ones which are produced by the backward scattering of neutrinos off the nuclei at relatively large distances from the supernova core. In this study we demonstrate that despite their ubiquity, such fast instabilities are unlikely to cause significant flavor conversions if the population of neutrinos in the backward direction is not large enough. Indeed, the scattering-induced instabilities can mostly impact the neutrinos traveling in the backward direction, which represent only a small fraction of neutrinos at large radii. We show that this can be explained by the shape of the unstable flavor eigenstates, which can be extremely peaked at the backward angles.

COVID-19 Vaccine and Long COVID: A Scoping Review

Abstract: As the COVID-19 pandemic progresses, changing definitions and therapeutics regarding the post-acute sequela of COVID-19, particularly long COVID, have become a subject of great interest and study. The study aims to describe the pathophysiology and discuss different therapeutic agents currently available for long COVID. Another objective is to assess comparative efficacy between different types of vaccines on symptoms of long COVID. A preliminary search was conducted using Ovid Medline, Embase, medRxiv, and NIH COVID-19 portfolios. A total of 16 studies were included in our review. Despite some of the data showing variable results, most of the vaccinated patients reported improvement in long COVID symptoms with no significant difference between various types of vaccines. Further trials are needed to better identify the comparative efficacy of vaccines for long COVID and ascertain other therapeutic modalities.

Clinical performance of methylation as a biomarker for cervical carcinoma in situ and cancer diagnosis: A worldwide study.

Abstract: The shift towards primary human papillomavirus (HPV)-based screening has necessitated the search for a secondary triage test that provides sufficient sensitivity to detect high-grade cervical intraepithelial neoplasia (CIN) and cancer, but also brings an improved specificity to avoid unnecessary clinical work and colposcopy referrals. We evaluated the performance of the previously described DNA-methylation test (S5) in detecting CIN3 and cancers from diverse geographic settings in high-, medium- and low-income countries, using the cut-off of 0.80 and exploratory cut-offs of 2.62 and 3.70. Assays were performed using exfoliated cervical specimens (n = 808) and formalin-fixed biopsies (n = 166) from women diagnosed with cytology-negative results (n = 220), CIN3 (n = 204) and cancer stages I (n = 245), II (n = 249), III (n = 28) and IV (n = 22). Methylation increased proportionally with disease severity (Cuzick test for trend, P < .0001). S5 accurately separated women with negative-histology from CIN3 or cancer (P < .0001). At the 0.80 cut-off, 543/544 cancers were correctly identified as S5 positive (99.81%). At cut-off 3.70, S5 showed a sensitivity of 95.77% with improved specificity. The S5 odds ratios of women negative for cervical disease vs CIN3+ were significantly higher than for HPV16/18 genotyping at all cut-offs (all P < .0001). At S5 cut-off 0.80, 96.15% of consistently high-risk human papillomavirus (hrHPV)-negative cancers (tested with multiple hrHPV-genotyping assay) were positive by S5. These cancers may have been missed in current primary hrHPV-screening programmes. The S5 test can accurately detect CIN3 and malignancy irrespective of geographic context and setting. The test can be used as a screening and triage tool. Adjustment of the S5 cut-off can be performed considering the relative importance given to sensitivity vs specificity.

Yttrium and rare-earth modified lithium orthoborates: Glass formation and vibrational activity

Abstract: Glass formation and structure-property relations were explored in highly modified borate glasses containing high loads of rare-earth elements, whose crystalline analogues display a trigonal to tetrahedral borate phase transition (BO33− → BO2O23−, where O and O− indicate bridging and non-bridging oxygen atoms). The resulting borate networks are completely depolymerized, where borate anions are crosslinked to rare-earth and modifier cations via ionic bonds. The borate structure was found to be based on a single structural unit, BO33− triangles, whose fundamental vibrations are all active in both the Raman and infrared. The local environment of the rare-earth ions in orthoborate glasses was studied with far infrared spectroscopy and, in some cases, by using terbium as a probe ion. A linear correlation was obtained between the effective force constant in the far infrared and the field strength of the rare-earth cation.

DC Sputtered Ultralow Loading Gold Nanofilm Electrodes for Detection of As (III) in Water

Abstract: This study investigates the use of DC sputtering, physical vapor deposition as a facile method for creating ultralow loading, Au/C electrodes for use in the detection of As (III) in water. The sputtered nanofilm electrodes on carbon papers, substantially reduces the amount of Au consumed per electrode, <10 μg cm−2, compared to use of wire, foil, or screen-printed electrodes. Linear stripping voltammetry (LSV) was chosen for analytical simplicity and ease of automation. Electrodes using Au nanoparticles supported on Vulcan XC 72 R carbon were also investigated but were not viable for LSV analysis due to capacitive current charging of the high surface area carbon. The DC sputtered, Au nanofilm electrodes were used to create calibration curves for concentrations of As (III) between 5 and 50 μg l−1 and the standard addition method was used in a surface water sample with 5.5 μg l−1 total As. Peak areas plotted against concentration displayed strong linear correlation with meaningful detection below the USEPA maximum contaminant level (MCL) of 10 μg l−1. To our knowledge, this is the first study which utilizes the facile and mass manufacturable DC sputtering method to produce As (III) sensing electrodes. The results of this study have implications for the development of single use, low-cost nanofilm electrodes for field As (III) electroanalysis.

The PYR‐PP2C‐CKL2 module regulates ABA‐mediated actin reorganization during stomatal closure

Abstract: Limiting water loss by reducing transpiration helps plants survive when water is limited. Under drought stress, abscisic acid (ABA)-mediated gene expression and anion channel activation regulate stomatal closure and stress responses. ABA-induced actin reorganization also affects stomatal closure, but the underlying molecular mechanism remains unclear. In this study, we discovered that under nonstress conditions, the clade A PP2C phosphatases, such as ABI1 and ABI2, interact with CKL2 and inhibit its kinase activity in Arabidopsis. Under drought stress, CKL2 kinase activity was released through the formation of a complex containing ABA, PP2C and a PYR1/PYL/RCAR family (PYL) receptor. The activated CKL2 regulating actin reorganization is another important process to maintain stomatal closure besides ABA-activated SnRK2 signaling. Moreover, CKL2 phosphorylated PYR1-LIKE 1, ABI1 and ABI2 at amino acid residues conserved among PYLs and PP2Cs, and stabilized ABI1 protein. Our results reveal that ABA signaling regulates actin reorganization to maintain stomatal closure during drought stress, and the feedback regulation of PYL1, ABI1 and ABI2 by the CKL2 kinase might fine-tune ABA signaling and affect plant ABA responses.

Integrating trace amounts of Pd nanoparticles into Mo₃N₂ nanobelts for an improved hydrogen evolution reaction

Abstract: Significant efforts have been directed towards the use of transition metal nitrides as electrocatalysts for the hydrogen evolution reaction (HER). Molybdenum nitride, despite its potential for scalable production, suffers from the bottleneck of poor catalytic activity. Furthermore the kinetics of the water dissociation process ought to be improved for enhancing its potential. Here, we report a facile method for the incorporation of a trace amount of Pd nanoparticles into Mo3N2 nanobelts (0.75 Pd/Mo3N2) for an enhanced HER in both acidic and alkaline solutions. When employed for the HER, the 0.75 wt% Pd/Mo3N2 nanobelt delivers excellent catalytic activity with overpotentials of 45 and 65 mV in 0.5 M H2SO4 and 1 M KOH at a current density of 10 mA cm-2. As-prepared 0.75 wt% Pd/Mo3N2 displays a smaller Tafel slope and offers substantial stability in both acidic and alkaline media under the same operating conditions. The improved performance of the as-prepared 0.75 wt% Pd/Mo3N2 points to fast charge transfer, higher electrical conductivity and synergistic effects between Pd and Mo. This work displays a direct method for reducing the use and cost associated with the use of platinum-group metals while also delivering superior HER catalytic performance.

Counteracting the effects of performance pressure on cheating: A self-affirmation approach.

Abstract: Pressure to perform is ubiquitous in organizations. Although performance pressure produces beneficial outcomes, it can also encourage cheating behavior. However, removing performance pressure altogether to reduce cheating is not only impractical but also eliminates pressure's benefits. Therefore, the purpose of this research is to test an intervention to counteract some of the most harmful effects of performance pressure. Specifically, I integrate the self-protection model of workplace cheating (Mitchell et al., 2018) with self-affirmation theory (Steele, 1988) to demonstrate the utility of a personal values affirmation intervention to short-circuit the direct and indirect effects of performance pressure on cheating through anger and self-serving cognitions. Two experiments were used to test these predictions. In a lab experiment, when people affirmed core personal values, the effect of performance pressure on cheating was neutralized; as was pressure's direct effect on anger and indirect effect on cheating via anger. A field experiment replicated the intervention's ability to mitigate performance pressure's direct effect on anger and indirect effect on cheating through anger. Altogether, this work provides a useful approach for combating the harmful effects of performance pressure and offers several theoretical and practical implications. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

3D-printable quaternary cementitious materials towards sustainable development: Mixture design and mechanical properties

Abstract: Development of 3D-printing technologies for cementitious materials becomes one of the driving forces to accelerate innovation in modern construction. The use of mineral and chemical admixtures in concrete has been found to benefit fresh and hardened properties and reduce the carbon footprint of portland cement. Towards this aim, four different supplementary cementitious materials, including metakaolin, silica fume, blast furnace slag, and sodium metasilicate, were utilized in binary, ternary, and quaternary cementitious blends. Flowability, setting, and compressive strength were measured to investigate the effects of different admixtures and their combinations on materials properties of printable mixtures. Selected mixtures were 3D-printed into cylinder specimens to assess their printing quality. The optimal mixture with up to 32.5% cement replacement was 3D-printed to evaluate mechanical properties (i.e., compressive strength and elastic modulus) based on prism specimens. The anisotropic behavior under compression load was observed. 3D-printed specimens tested under perpendicular direction showed the lowest compressive strength but the highest elastic modulus. • Material properties of 12 mixtures, including binary, ternary, and quaternary cementitious blends, were investigated. • According to the printing system and tests, a printable mixture with 32.5% cement replacement was selected for this study. • Mechanical properties of 3D-printed prisms in perpendicular and longitudinal directions were compared with cast prisms.

Environmental harshness mediates the relationship between aboveground and belowground communities in Antarctica

Abstract: Linkages between aboveground and belowground communities are a key but globally under-researched component of responses to environmental change. Given the logistical complications to studying these relationships, much of our knowledge derives from laboratory experiments and localized field studies which have so far yielded inconsistent results. Because environmental factors may alter relationships between above- and belowground communities, there is a need for broad-scale field studies testing these interactions. The Antarctic Peninsula provides an ideal test setting, given the relatively simple communities both above- and belowground. The Peninsula is also experiencing rapid environmental changes, including alterations in species diversity and distribution both above- and belowground. Thus, an improved understanding of the broad-scale consequences of altered environments and vegetation communities for the soil microbiome is of high priority. To determine the nature and strength of the relationship between in situ plant and soil communities across a broad spatial scale and range of environmental conditions, we sampled soil communities at 9 locations (spanning 60–72°S along the Scotia Arc and Antarctic Peninsula) beneath the major aboveground habitats (moss, grass, lichen, algae and bare soil). We measured a comprehensive suite of soil physicochemical properties, microbial (bacterial and fungal) diversity and composition, and invertebrate abundance and community composition to determine the relationships between plant and soil communities. Our results suggest that, with increased environmental severity, plant cover types become more important for influencing the physicochemical soil environment, and therefore the soil microbial communities. Although we found site-specific relationships, broad-scale patterns reveal significant differences among bare soils and vegetated soils, particularly soils beneath grass and moss. This suggests that expansion of vegetation communities under current climate warming projections will be accompanied by shifts in the soil microbiome, with important implications for the ecosystem functioning with which they are associated.

Temporal Effects of Monsoon Rainfall Pulses on Plant Available Nitrogen in a Chihuahuan Desert Grassland

Abstract: Drylands are often characterized by a pulse dynamics framework in which episodic rain events trigger brief pulses of biological activity and resource availability that regulate primary production. In the northern Chihuahuan Desert, growing season precipitation typically comes from monsoon rainstorms that stimulate soil microbial processes like decomposition, releasing inorganic nitrogen needed by plant processes. Compared to microbes, plants require greater amounts of soil moisture, typically from larger monsoon storms predicted to become less frequent and more intense in the future. Yet field-based studies linking rainfall pulses with soil nutrient dynamics are rare. Consequently, little is known about how changes in rainfall patterns may affect plant available nitrogen in dryland soils, particularly across temporal scales. We measured daily and seasonal responses of soil inorganic nitrogen and related parameters to experimentally applied small frequent and large infrequent rain events throughout a summer growing season in a Chihuahuan Desert grassland. Contrary to long-standing theories around resource pulse dynamics in drylands, nitrogen availability did not pulse following experimental rain events. Moreover, large infrequent events resulted in significantly less plant available nitrogen despite causing distinct pulses of increased soil moisture availability that persisted for several days. Overall, nitrogen availability increased over the growing season, especially following small frequent rain events that also stimulated some microbial ecoenzymatic activities. Our results suggest that projected changes in climate to fewer, larger rain events could significantly impact primary production in desert grasslands by decreasing plant available nitrogen when soil moisture is least limiting to plant growth.

Green Tensor Analysis of Lattice Resonances in Periodic Arrays of Nanoparticles

Abstract: When arranged in a periodic geometry, arrays of metallic nanostructures are capable of supporting collective modes known as lattice resonances. These modes, which originate from the coherent multiple scattering between the elements of the array, give rise to very strong and spectrally narrow optical responses. Here, we show that, thanks to their collective nature, the lattice resonances of a periodic array of metallic nanoparticles can mediate an efficient long-range coupling between dipole emitters placed near the array. Specifically, using a coupled dipole approach, we calculate the Green tensor of the array connecting two points and analyze its spectral and spatial characteristics. This quantity represents the electromagnetic field produced by the array at a given position when excited by a unit dipole emitter located at another one. We find that, when a lattice resonance is excited, the Green tensor is significantly larger and decays more slowly with distance than the Green tensor of vacuum. Therefore, in addition to advancing the fundamental understanding of lattice resonances, our results show that periodic arrays of nanostructures are capable of enhancing the long-range coupling between collections of dipole emitters, which makes them a promising platform for applications such as nanoscale energy transfer and quantum information processing.

Effect of the addition of different sodium alginates on viscoelastic, structural features and hydrolysis kinetics of corn starch gels

Abstract: Corn starch gels (1:4 w:w) were made with the addition (up to 2% w/w starch basis) of sodium alginates of different average molecular sizes and nature. Rheology of the starchy gels were characterized to evaluate their viscoelasticity. Gels were subjected to in vitro digestion to estimate the effect of alginates addition on glycemic response. Tested alginates significantly decreased the value of the elastic modulus of gels. The coordination number obtained from complex modulus indicated that in general, less compact structures were obtained in the presence of alginates. These results were confirmed by scanning electron micrographs, where significant differences in the structure of alginate-corn starch gels were observed, but molecular size of alginates was not critical. Hydrolysis rate decreased with the presence of alginates in corn starch gels by interactions of alginates with leached amylose. At high alginate content, slower hydrolysis rates were determined when the most hygroscopic alginates were added. • Sodium alginates (SA) addition decreased the firmness of corn starch (CS) gels. • SA promote anisotropic and less compact structures in CS gels. • Molecular size of SA was not critical to form SA-CS gels structures. • Hydrolysis rate decreased with the SA addition in CS gels.

Strategic flexibility in small firms

Abstract: Contrasted with their larger counterparts, small firms are disadvantaged due to their limited resources, economies of scale, and managerial expertise. However, the ability to respond and adapt promptly in today’s rapidly changing environment provides SMEs advantage over larger firms. In this paper, we argue that SMEs need to overcome resource disadvantages, leverage structural advantages, and develop new relational advantages in collaboration with partners to enhance their strategic flexibility for gaining competitive advantage. Specifically, we conjecture that building proactively strategic relationships with suppliers and logistics providers in addition to improving information quality could allow these entities to develop strategic flexibility and improve performance. We use structural equation modeling to assess the proposed model on a sample of 75 small firms located in India.

In-Well Pumping of a Membrane External-Cavity Surface-Emitting Laser

Abstract: We present a detailed characterization and comparative study of a membrane external-cavity surface-emitting laser (MECSEL) operating in the λ = 1125-1190 nm wavelength range under in-well pumping (at 1070 nm) and barrier-pumping (at 808 nm). The slope efficiency of the laser is significantly improved from 21% with barrier-pumping to 39% when pumping only the quantum wells at 1070 nm at a heat-sink temperature of 10 °C. To address the low pump absorbance with in-well pumping, we design and implement a low-aberration multi-pass pumping scheme. An optical output power of 28.5 W and slope efficiency of ∼28% is achieved with 8 circulating passes. This represents the highest output power demonstrated in any MECSEL, as well as the highest output power in-well pumped vertical external-cavity surface-emitting laser (VECSEL). It is noted that our reported output power is only limited by the available laser input power and no thermal roll-over is observed.

Ictal Theta Power as an Electroconvulsive Therapy Safety Biomarker

Abstract: Objective Electroconvulsive therapy (ECT) remains the benchmark for treatment resistant depression, yet its cognitive adverse effects have a negative impact on treatment. A predictive safety biomarker early in ECT treatment is needed to identify patients at cognitive risk to maximize therapeutic outcomes and minimize adverse effects. We used ictal electroencephalography frequency analysis from suprathreshold treatments to assess the relationships between ECT dose, ictal power across different frequency domains, and cognitive outcomes. Methods Seventeen subjects with treatment resistant depression received right unilateral ECT. Structural magnetic resonance imaging was obtained pre-ECT for electric field modeling to assess ECT dose. Serial assessments with 24-lead electroencephalography captured ictal activity. Clinical and cognitive assessments were performed before and after ECT. The primary cognitive outcome was the change in Delis Kaplan Executive Function Verbal Fluency Letter Fluency. Results Ictal theta (4–8 Hz) power in the Fp1/Fp2 channels was associated with both whole-brain electric field strength (t(2,12) = 19.5, P = 0.007)/(t(2,10) = 21.85, P = 0.02) and Delis Kaplan Executive Function Verbal Fluency Letter Fluency scores (t(2,12) = −2.05, P = 0.05)/(t(2,10) = −2.20, P = 0.01). Other frequency bands (beta, alpha, delta, and gamma) did not demonstrate this relationship. Conclusions This pilot data identify ictal theta power as a potential safety biomarker in ECT and is related to the strength of the ECT dose. Ictal theta power could prove to be a convenient and powerful tool for clinicians to identify those patients most susceptible to cognitive impairment early in the treatment series. Additional studies are needed to assess the role of longitudinal changes in ictal theta power throughout the ECT series.

The effective theory of gravity and dynamical vacuum energy

Abstract: A bstract Gravity and general relativity are considered as an Effective Field Theory (EFT) at low energies and macroscopic distances. The effective action of the conformal anomaly of light or massless quantum fields has significant effects on macroscopic scales, due to associated light cone singularities that are not captured by an expansion in local curvature invariants. A compact local form for the Wess-Zumino effective action of the conformal anomaly and stress tensor is given, requiring the introduction of a new light scalar field, which it is argued should be included in the low energy effective action for gravity. This scalar conformalon couples to the conformal part of the spacetime metric and allows the effective value of the vacuum energy, described as a condensate of an exact 4-form abelian gauge field strength F = dA , to change in space and time. This is achieved by the identification of the torsion dependent part of the Chern-Simons 3-form of the Euler class with the gauge potential A , which enters the effective action of the conformal anomaly as a J · A interaction analogous to electromagnetism. The conserved 3-current J describes the worldtube of 2-surfaces that separate regions of differing vacuum energy. The resulting EFT thus replaces the fixed constant Λ of classical gravity, and its apparently unnaturally large sensitivity to UV physics, with a dynamical condensate whose ground state value in empty flat space is Λ eff = 0 identically. By allowing Λ eff to vary rapidly near the 2-surface of a black hole horizon, the proposed EFT of dynamical vacuum energy provides an effective Lagrangian framework for gravitational condensate stars, as the final state of complete gravitational collapse consistent with quantum theory. The possible consequences of dynamical vacuum dark energy for cosmology, the cosmic coincidence problem, and the role of conformal invariance for other fine tuning issues in the Standard Model are discussed.

Screening for Excessive Alcohol Consumption in Emergency Departments: A Nationwide Assessment of Emergency Department Physicians.

Abstract: Objective To assess current screening practices for excessive alcohol consumption, as well as perceived barriers, perceptions, and attitudes toward performing this screening among emergency department (ED) physicians. Design A brief online assessment of screening practices for excessive drinking was disseminated electronically to a representative panel of ED physicians from November 2016 to January 2017. Descriptive statistics were calculated on the frequency of alcohol screening, factors affecting screening, and attitudes toward screening. Setting An online assessment was sent to a national panel of ED physicians. Participants A panel of ED physicians who volunteered to be part of the American College of Emergency Physicians Emergency Medicine Practice Research Network survey panel. Main outcome measure The primary outcome measures were the percentage of respondents who reported screening for excessive alcohol consumption and the percentage of respondents using a validated excessive alcohol consumption screening tool. Results Of the 347 ED physicians evaluated (38.6% response rate), approximately 16% reported "always/usually," 70% "sometimes," and 14% "never" screening adult patients (≥18 years) for excessive alcohol use. Less than 20% of the respondents who screened for excessive drinking used a recommended screening tool. Only 10.5% of all respondents (15.4% "always," 9.5% "sometimes" screened) received an electronic health record (EHR) reminder to screen for excessive alcohol use. Key barriers to screening included limited time (66.2%) and treatment options for patients with drinking problems (43.1%). Conclusions Only 1 in 6 ED physicians consistently screened their patients for excessive drinking. Increased use of EHR reminders and other systems interventions (eg, electronic screening and brief intervention) could help improve the delivery of screening and follow-up services for excessive drinkers in EDs.

A proliferation of images: Trends, obstacles, and opportunities for visual literacy

Abstract: Visual literacy equips learners with the dispositions to critically create, analyse, use, and share visual information. As one component of a discerning, ethical citizenry, visual literacy has become more essential in a rapidly evolving information ecosystem. Against this backdrop, the current Association of College and Research Libraries Visual Literacy Task Force conducted qualitative research from 2019 to 2021, interviewing visual literacy and information literacy experts to identify emergent trends, challenges, and opportunities shaping visual literacy in the twenty-first century. The findings from this study broaden current understandings of visual literacy and empower learners, educators, and practitioners to critically create, share, evaluate, and use visuals in an ever-changing information landscape.