Outstanding Discrepancies Research Articles

Progress in direct measurements of the Hubble constant

One of the most exciting and pressing issues in cosmology today is the discrepancy between some measurements of the local Hubble constant and other values of the expansion rate inferred from the observed temperature and polarization fluctuations in the cosmic microwave background (CMB) radiation. Resolving these differences holds the potential for the discovery of new physics beyond the standard model of cosmology: Lambda Cold Dark Matter (ΛCDM), a successful model that has been in place for more than 20 years. Given both the fundamental significance of this outstanding discrepancy, and the many-decades-long effort to increase the accuracy of the extragalactic distance scale, it is critical to demonstrate that the local measurements are convincingly free from residual systematic errors. We review the progress over the past quarter century in measurements of the local value of the Hubble constant, and discuss remaining challenges. Particularly exciting are new data from the James Webb Space Telescope (JWST), for which we present an overview of our program and first results. We focus in particular on Cepheids and the Tip of the Red Giant Branch (TRGB) stars, as well as a relatively new method, the JAGB (J-Region Asymptotic Giant Branch) method, all methods that currently exhibit the demonstrably smallest statistical and systematic uncertainties. JWST is delivering high-resolution near-infrared imaging data to both test for and to address directly several of the systematic uncertainties that have historically limited the accuracy of extragalactic distance scale measurements (e.g., the dimming effects of interstellar dust, chemical composition differences in the atmospheres of stars, and the crowding and blending of Cepheids contaminated by nearby previously unresolved stars). For the first galaxy in our program, NGC 7250, the high-resolution JWST images demonstrate that many of the Cepheids observed with the Hubble Space Telescope (HST) are significantly crowded by nearby neighbors. Avoiding the more significantly crowded variables, the scatter in the JWST near-infrared (NIR) Cepheid PL relation is decreased by a factor of two compared to those from HST, illustrating the power of JWST for improvements to local measurements of H 0. Ultimately, these data will either confirm the standard model, or provide robust evidence for the inclusion of additional new physics.

Deep reaction network exploration of glucose pyrolysis

Resolving the reaction networks associated with biomass pyrolysis is central to understanding product selectivity and aiding catalyst design to produce more valuable products. However, even the pyrolysis network of relatively simple [Formula: see text]-D-glucose remains unresolved due to its significant complexity in terms of the depth of the network and the number of major products. Here, a transition-state-guided reaction exploration has been performed that provides complete pathways to most significant experimental pyrolysis products of [Formula: see text]-D-glucose. The resulting reaction network involves over 31,000 reactions and transition states computed at the semiempirical quantum chemistry level and approximately 7,000 kinetically relevant reactions and transition states characterized with density function theory, comprising the largest reaction network reported for biomass pyrolysis. The exploration was conducted using graph-based rules to explore the reactivities of intermediates and an adaption of the Dijkstra algorithm to identify kinetically relevant intermediates. This simple exploration policy surprisingly (re)identified pathways to most major experimental pyrolysis products, many intermediates proposed by previous computational studies, and also identified new low-barrier reaction mechanisms that resolve outstanding discrepancies between reaction pathways and yields in isotope labeling experiments. This network also provides explanatory pathways for the high yield of hydroxymethylfurfural and the reaction pathway that contributes most to the formation of hydroxyacetaldehyde during glucose pyrolysis. Due to the limited domain knowledge required to generate this network, this approach should also be transferable to other complex reaction network prediction problems in biomass pyrolysis.

Implementation of medication reconciliation at admission and discharge in Ministry of Defense Health Services hospitals: a multicentre study

There is potential for many medication errors to occur due to the complex medication use process. The medication reconciliation process can significantly lower the incidence of medication errors that may...

Western U.S. Deformation Models for the 2023 Update to the U.S. National Seismic Hazard Model

Abstract This report describes geodetic and geologic information used to constrain deformation models of the 2023 update to the National Seismic Hazard Model (NSHM), a set of deformation models to interpret these data, and their implications for earthquake rates in the western United States. Recent updates provide a much larger data set of Global Positioning System crustal velocities than used in the 2014 NSHM, as well as hundreds of new faults considered as active sources for the 2023 NSHM. These data are interpreted by four geodetic models of deformation that estimate fault slip rates and their uncertainties together with off-fault moment release rates. Key innovations in the 2023 NSHM relative to past practice include (1) the addition of two new (in addition to two existing) deformation models, (2) the revision and expansion of the geologic slip rate database, (3) accounting for fault creep through development of a creep-rate model that is employed by the four deformation models, and (4) accounting for time-dependent earthquake-cycle effects through development of viscoelastic models of the earthquake cycle along the San Andreas fault and the Cascadia subduction zone. The effort includes development of a geologic deformation model that complements the four geodetic models. The current deformation models provide a new assessment of outstanding discrepancies between geologic and geodetic slip rates, at the same time highlighting the need for both geologic and geodetic slip rates to robustly inform the earthquake rate model.

Medication Reconciliation at hospital admission and discharge: Evaluation of fidelity and process outcomes in a real-world setting.

The study aimed to assess the fidelity of Medication Reconciliation (MR) delivered by the pharmacist at hospital admission and discharge, and the process outcomes. Prospective study conducted in cardiology and cardiovascular surgery unit of a university hospital between September 2019 and January 2020. Independent observers collected data to measure MR fidelity, related to coverage, sources of information used to collect medication history and presence of outstanding and resolved Undocumented Discrepancies (UD). Process outcomes included medication errors and their potential to cause harm, identified by the pharmacist during the formal MR process. Of the eligible patients, 122 (69.7%) had their medications reconciled in a timely manner at hospital admission and 50 (43.8%) at discharge. The pharmacist consulted 2.76 (±0.8) sources of information to build the medication history, on average. At least one outstanding UD was found in 101 (82.8%) patients at admission and in 41 (82.0%), at discharge. The average number of outstanding UD per patient at admission and discharge was 3.0 (±2.6) and 2.4 (±1.9), respectively. The UD communicated to the physician by the pharmacist during the formal MR process, involved mainly omission errors and were classified as requiring monitoring or potentially necessary intervention. In the univariate analysis, the number of drugs pre-admission and admission, the reason for admission and non-elective readmission in 30days were associated with the presence of medication errors at admission. This study found a high number of UD, suggesting flaws in the implementation of MR and highlight the importance of quality measurement.

Constraining the Primordial Lithium Abundance: New Cross Section Measurement of the 7Be + n Reactions Updates the Total 7Be Destruction Rate

Abstract The cosmological lithium problem (CLP) stems from the outstanding discrepancy between theoretical predictions and astronomical observations of primordial lithium abundances. For the radiogenic production of 7Li, 7Be plays a pivotal role in the Big Bang nucleosynthesis (BBN). Nevertheless, the data for neutron-induced 7Be destruction processes were still sparse, and especially lacked information on the contributions of transitions to the 7Li excited states. In this work, we have determined the 7Be ( n , p 0 ) 7 Li, 7Be ( n , p 1 ) 7 Li*, and 7Be ( n , α ) 4 He reaction cross sections by means of the Trojan Horse method. The present and the previous data were analyzed together by a multichannel R-matrix fit, providing an improved uncertainty evaluation of the ( n , p 0 ) channel and the first-ever quantification of the ( n , p 1 ) contribution in the BBN-relevant energy range. We implemented the revised total reaction rate summing both the ( n , p 0 ) and ( n , p 1 ) contributions in a state-of-the-art BBN code PRIMAT. As a consequence, the present nuclear-physics data offers a reduction of the predicted 7Li abundance by about one-tenth, which would impose a stricter constraint on BBN and head us in the correct direction to the CLP solution.

Unexpected Oligomerization of Small α-Dicarbonyls for Secondary Organic Aerosol and Brown Carbon Formation

Large amounts of small α-dicarbonyls (glyoxal and methylglyoxal) are produced in the atmosphere from photochemical oxidation of biogenic isoprene and anthropogenic aromatics, but the fundamental mechanisms leading to secondary organic aerosol (SOA) and brown carbon (BrC) formation remain elusive. Methylglyoxal is commonly believed to be less reactive than glyoxal because of unreactive methyl substitution, and available laboratory measurements showed negligible aerosol growth from methylglyoxal. Herein, we present experimental results to demonstrate striking oligomerization of small α-dicarbonyls leading to SOA and BrC formation on sub-micrometer aerosols. Significantly more efficient growth and browning of aerosols occur upon exposure to methylglyoxal than glyoxal under atmospherically relevant concentrations and in the absence/presence of gas-phase ammonia and formaldehyde, and nonvolatile oligomers and light-absorbing nitrogen-heterocycles are identified as the dominant particle-phase products. The distinct aerosol growth and light absorption are attributed to carbenium ion-mediated nucleophilic addition, interfacial electric field-induced attraction, and synergetic oligomerization involving organic/inorganic species, leading to surface- or volume-limited reactions that are dependent on the reactivity and gaseous concentrations. Our findings resolve an outstanding discrepancy concerning the multiphase chemistry of small α-dicarbonyls and unravel a new avenue for SOA and BrC formation from atmospherically abundant, ubiquitous carbonyls and ammonia/ammonium sulfate.

Resolving the (g−2)μ and B anomalies with leptoquarks and a dark Higgs boson

At present, there are outstanding discrepancies between standard model predictions and measurements of the muon's $g-2$ and several $B$-meson properties. We resolve these anomalies by considering a two-Higgs-doublet model extended to include leptoquarks and a dark Higgs boson $S$. The leptoquarks modify $B$-meson decays and also induce an $S \gamma \gamma$ coupling, which contributes to the muon's $g-2$ through a Barr-Zee diagram. We show that, for TeV-scale leptoquarks and dark Higgs boson masses $m_{S} \sim 10-200~\text{MeV}$, a consistent resolution to all of the anomalies exists. The model predicts interesting new decays, such as $B \to K^{(*)} e^+ e^-$, $B \to K^{(*)} \gamma \gamma$, $K \to \pi \gamma \gamma$, and $h \to \gamma \gamma \gamma \gamma$, with branching fractions not far below current bounds.

Lamb-dips and Lamb-peaks in the saturation spectrum of HD.

The saturation spectrum of the R(1) transition in the (2-0) band in hydrogen deuteride (HD) is found to exhibit a composite line shape, involving a Lamb-dip and a Lamb-peak. We propose an explanation for such behavior based on the effects of crossover resonances in the hyperfine substructure, which is made quantitative in a density matrix calculation. This resolves an outstanding discrepancy on the rovibrational R(1) transition frequency, which is now determined at 217,105,181,901 (50) kHz and in agreement with current theoretical calculations.

Role of electron-phonon coupling and thermal expansion on band gaps, carrier mobility, and interfacial offsets in kesterite thin-film solar cells

The efficiencies of solar cells based on kesterite Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe4 (CZTSe) are limited by a low open-circuit voltage due to high rates of non-radiative electron-hole recombination. To probe the origin of this bottleneck, we calculate the band offset of CZTS(Se) with CdS, confirming a weak spike of 0.1 eV for CZTS/wurtzite-CdS and a strong spike of 0.4 eV for CZTSe/wurtzite-CdS. We also consider the effects of temperature on the band alignment, finding that increasing temperature significantly enhances the spike-type offset. We further resolve an outstanding discrepancy between the measured and calculated phonon frequencies for the kesterites, and use these to estimate the upper limit of electron and hole mobilities based on optic phonon Fröhlich scattering, which uncovers an intrinsic asymmetry with faster (minority carrier) electron mobility.

Topological Electride Y2C.

Two-dimensional (2D) electrides are layered ionic crystals in which anionic electrons are confined in the interlayer space. Here, we report a discovery of nontrivial [Formula: see text] topology in the electronic structures of 2D electride Y2C. Based on first-principles calculations, we found a topological [Formula: see text] invariant of (1; 111) for the bulk band and topologically protected surface states in the surfaces of Y2C, signifying its nontrivial electronic topology. We suggest a spin-resolved angle-resolved photoemission spectroscopy (ARPES) measurement to detect the unique helical spin texture of the spin-polarized topological surface state, which will provide characteristic evidence for the nontrivial electronic topology of Y2C. Furthermore, the coexistence of 2D surface electride states and topological surface state enables us to explain the outstanding discrepancy between the recent ARPES experiments and theoretical calculations. Our findings establish a preliminary link between the electride in chemistry and the band topology in condensed-matter physics, which are expected to inspire further interdisciplinary research between these fields.

Economic and Humanistic Burden of Osteoarthritis: A Systematic Review of Large Sample Studies.

Osteoarthritis (OA) consumes a significant amount of healthcare resources, and impairs the health-related quality of life (HRQoL) of patients. Previous reviews have consistently found substantial variations in the costs of OA across studies and countries. The comparability between studies was poor and limited the detection of the true differences between these studies. To review large sample studies on measuring the economic and/or humanistic burden of OA published since May 2006. We searched MEDLINE and EMBASE databases using comprehensive search strategies to identify studies reporting economic burden and HRQoL of OA. We included large sample studies if they had a sample size ≥1000 and measured the cost and/or HRQoL of OA. Reviewers worked independently and in duplicate, performing a cross-check between groups to verify agreement. Within- and between-group consolidation was performed to resolve discrepancies, with outstanding discrepancies being resolved by an arbitrator. The Kappa statistic was reported to assess the agreement between the reviewers. All costs were adjusted in their original currency to year 2015 using published inflation rates for the country where the study was conducted, and then converted to 2015 US dollars. A total of 651 articles were screened by title and abstract, 94 were reviewed in full text, and 28 were included in the final review. The Kappa value was 0.794. Twenty studies reported direct costs and nine reported indirect costs. The total annual average direct costs varied from US$1442 to US$21,335, both in USA. The annual average indirect costs ranged from US$238 to US$29,935. Twelve studies measured HRQoL using various instruments. The Short Form 12 version 2 scores ranged from 35.0 to 51.3 for the physical component, and from 43.5 to 55.0 for the mental component. Health utilities varied from 0.30 for severe OA to 0.77 for mild OA. Per-patient OA costs are considerable and a patient's quality of life remains poor. Variations in costing methods are a barrier to understanding the true differences in the costs of OA between studies. Standardizing healthcare resource items, the definition of OA-relevant costs, and productivity loss measures would facilitate the comparison.

Angular Dependence of the Pinning Fields for Hard/Soft Multilayers

The exchange-coupled hard/soft magnetic material, proposed in 1991 by Kneller et al.[1], is widely regarded as an excellent next-generation permanent magnetic material. A perfect composite material is expected to hold a large energy product because of the combination of the large remanence of the soft phase and the high coercivity of the hard phase. A giant energy product as high as 120 MG Oe was thus predicted by Skomski and Coey in 1993 [2]. However, experimental values are much smaller [3-4], where easy axis deviations are found to be an important factor leading to the outstanding discrepancy. In the meantime, the magnetic reversal mechanism also varies with β, the angle between the easy axis and the applied field. In this work, hysteresis loops and energy products have been calculated for hard/soft multilayers with various β based on a self-contained micromagnetic model, focusing on the angular dependent magnetic reversal mechanism.

Highly structured electron anisotropy in collisionless reconnection exhausts

AbstractResults from two‐dimensional particle‐in‐cell simulations of collisionless magnetic reconnection with zero guide field discussed in this paper reveal that around the time when the reconnection rate peaks, electron velocity distributions become highly structured in magnetic islands and open exhausts. Rings, arcs, and counterstreaming beams are generic and lasting components of the exhaust electron distributions. The temporal dependence of electron distributions provides a perspective to explain an outstanding discrepancy concerning the degree of electron anisotropy in reconnection exhausts and enables inference of the reconnection phase based on observed anisotropic electron distributions. Some of the structures predicted by our simulations are confirmed by measurements from the Cluster spacecraft during its encounter with reconnection exhausts in the magnetotail.

Van der Waals interactions in the ground state of Mg(BH4)2from density functional theory

In order to resolve an outstanding discrepancy between experiment and theory regarding the ground-state structure of Mg(BH4)2, we examine the importance of long-range dispersive interactions on the compound's thermodynamic stability. Careful treatment of the correlation effects within a recently developed nonlocal van der Waals density functional (vdW-DF) leads to a good agreement with experiment, favoring the {\alpha}-Mg(BH4)2 phase (P6122) and a closely related Mn(BH4)2-prototype phase (P3112) over a large set of polymorphs at low temperatures. Our study demonstrates the need to go beyond (semi)local density functional approximations for a reliable description of crystalline high-valent metal borohydrides.

Symmetries and the search for physics beyond the standard model

Beginning with an introduction to its significance, we briefly review the status of our knowledge of the strangeness content of the nucleon, both experimental and theoretical. We then recall how the success of the corresponding experimental program at JLab led to an unanticipated improvement in the precision with which we constrain the possible existence of parity violating lepton-quark interactions beyond the Standard Model. This leads naturally to the consideration of the major outstanding discrepancy in the evolution of sin 2 θ W . In particular, we explain how the nuclear modification of parton distributions, combined with charge symmetry violation eliminate this discrepancy.

Anion-Catalyzed Dissolution of NO2 on Aqueous Microdroplets

Fifty-seven years after NO(x) (NO + NO(2)) were identified as essential components of photochemical smog, atmospheric chemical models fail to correctly predict *OH/HO(2)* concentrations under NO(x)-rich conditions. This deficiency is due, in part, to the uncertain rates and mechanism for the reactive dissolution of NO(2)(g) (2NO(2) + H(2)O = NO(3)(-) + H(+) + HONO) in fog and aerosol droplets. Thus, state-of-the-art models parametrize the uptake of NO(2) by atmospheric aerosol from data obtained on "deactivated tunnel wall residue". Here, we report experiments in which NO(3)(-) production on the surface of microdroplets exposed to NO(2)(g) for approximately 1 ms is monitored by online thermospray mass spectrometry. NO(2) does not dissolve in deionized water (NO(3)(-) signals below the detection limit) but readily produces NO(3)(-) on aqueous NaX (X = Cl, Br, I) microdroplets with NO(2) uptake coefficients gamma that vary nonmonotonically with electrolyte concentration and peak at gamma(max) approximately 10(-4) for [NaX] approximately 1 mM, which is >10(3) larger than that in neat water. Since I(-) is partially oxidized to I(2)(*-) in this process, anions seem to capture NO(2)(g) into X-NO(2)(*-) radical anions for further reaction at the air/water interface. By showing that gamma is strongly enhanced by electrolytes, these results resolve outstanding discrepancies between previous measurements in neat water versus NaCl-seeded clouds. They also provide a general mechanism for the heterogeneous conversion of NO(2)(g) to (NO(3)(-) + HONO) on the surface of aqueous media.

Resolving the Mass Discrepancy between Strong and Weak Lensing Methods

We readdress the outstanding cluster mass discrepancy between strong and weak gravitational lensing techniques utilizing updated data of both giant arcs and weak lensing measurements from the literature. We find that the systematically higher values of cluster masses revealed by strong lensing can be attributed to the oversimplification of the lensing model when estimating the cluster mass enclosed within the giant arcs. This arises because inhomogeneities and substructures in the central cores of clusters may invalidate the spherical symmetry assumption used widely in previous applications. When a more realistic modeling of the arcs is used, then the masses by strong lensing agree fairly well with those given by weak lensing when both are extrapolated to the same cluster regions. We conclude that as of now no significant discrepancy has been found among different cluster mass estimators including optical galaxies, X-ray gas and lensing.

Assays of ceruloplasmin vs myeloperoxidase: Witnessing the great battle, or mixing chalk and cheese?

A paper in this issue [Panasenko et al., Biophysics 53 (4), 268 (2008)] furthers the idea of myeloperoxidase inhibition by ceruloplasmin, confirming the earlier reports with standard chlorination and peroxidase tests, and introducing a new version of the luminol chemiluminescence assay. However, there are outstanding discrepancies in the data on ceruloplasmin efficacy and their interpretation. In my opinion, they can be resolved only admitting that the supposedly equivalent assays register essentially different types of process, which involve the same chemical entities but on different spatiotemporal scales. The immediate flash caused by hydrogen peroxide in the myeloperoxidase/luminol/chloride mixture must reflect the non-equilibrium events within and/or at the surface of the enzyme molecule pre-loaded with the reactants. This phenomenon (which should perhaps be called “prompt chemiluminescence” in contrast to the much longer glow recorded in all usual assays and associated with secondary reactions in the bulk) is quite interesting in the biophysical aspect. It can be used for functional dissection of such multipathway, multilevel systems, and in particular, can indeed help clarify the situation concerning the putative ceruloplasmin control over myeloperoxidase.

Coulomb-Enhanced Spin-Orbit Splitting: The Missing Piece in theSr2RhO4Puzzle

The outstanding discrepancy between the measured and calculated (local-density approximation) Fermi surfaces in the well-characterized, paramagnetic Fermi liquid Sr2RhO4 is resolved by including the spin-orbit coupling and Coulomb repulsion. This results in an effective spin-orbit coupling constant enhanced 2.15 times over the bare value. A simple formalism allows discussion of other systems. For Sr2RhO4, the experimental specific-heat and mass enhancements are found to be 2.2.