Compositions and Ni-Cu-Platinum Group Element Tenors of Nova-Bollinger Ores with Implications for the Origin of Pt Anomalies in Platinum Group Element-Poor Massive Sulfides

The Nova-Bollinger Ni-Cu-platinum group element (PGE) deposit in the Fraser zone of the Albany-Fraser orogen consists of two main orebodies, Nova and Bollinger, hosted by the same tube-shaped intrusion but having distinctly different Ni tenors of around 6.5 and 4.8 wt %, respectively. Nova is also higher in Pd, but Cu and Pt tenors are similar. Both deposits have very low PGE tenors, with average Pd concentrations of 110 ppb in massive sulfide at Bollinger and 136 ppb at Nova. The Nova and Bollinger orebodies show relatively little internal differentiation overall on deposit scale but show strong differentiation into chalcopyrite-rich and chalcopyrite-poor regions at a meter scale. This differentiation is more prevalent at Nova, where massive sulfide-filled vein arrays are more extensively developed, and in massive ores, particularly veins, than in net-textured ores. Net-textured and disseminated ores have on average Ni and Cu grades and tenors similar to those of massive, semimassive, and breccia ores in the same orebody but a smaller range of variation, largely due to a more limited extent of sulfide liquid fractionation and higher average concentrations of Pt and Pd than adjacent massive ores. Unusually for differentiated magmatic sulfides, there is no systematic positive correlation between Pt, Pd, and Cu. A partial explanation for the lack of a Pd-Cu correlation is that Pd was partitioned into peritectic pentlandite in the middle stages of sulfide liquid solidification. This explanation is not applicable to Pt, as Pt characteristically forms its own phases rather than residing in base metal sulfides. PGE tenors are very low in both orebodies, very similar to those observed in other Ni-Cu-Co sulfide ores in orogenic settings, notably the Savannah and Savannah North orebodies. This depletion is attributed to sulfide retention in the mantle source of the parent magmas rather than to previous fractional extraction of sulfide liquid in staging chambers or feeder networks. The higher Ni and Pd tenors at Nova are attributed to reworking and upgrading of precursor sulfide liquid originally deposited upstream at the Bollinger site. Replicate analyses of multiple jaw-crusher splits returned highly variable Pt and Au assays but much smaller relative errors in the other PGEs. The poor Pt and Au reproducibilities are attributed to nugget effects, explicable by much of the Pt and Au in the samples being present in sparse Pt- and Au-rich grains. This is principally true for Pt in massive rather than disseminated ores, accounting for a strong contrast in the distribution of Pt/Pd ratios between the two ore types. Numerical simulation suggests that Pt is predominantly resident in Pt-rich platinum group minerals with grain diameters of 100 μm or more and that at the low (<100 ppb) concentrations in these ores, this results in most assays significantly underreporting Pt. This is likely to be true in other low-PGE ores, such that apparent negative Pt anomalies in massive ores may in such cases be attributable to sampling artifacts.

Assessment of GRACE/GRACE Follow-On Estimates of Global Mean Ocean Mass Change

Global mean sea level has increased ~3.5 mm/yr over several decades due to increases in ocean mass and changes in sea water density. Ocean mass, accounting for about two-thirds of the increase, can be directly measured by the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GFO) satellites. An independent measure is obtained by combining satellite altimetry (measuring total sea level change) and Argo float data (measuring steric changes associated with sea water density). Many previous studies have reported that the two estimates of global mean ocean mass (GMOM) change are in good agreement within stated confidence intervals. Recently, particularly since 2016, estimates by the two methods have diverged. A partial explanation appears to be a spurious variation in steric sea level data. An additional contributor may be deficiencies in Glacial Isostatic Adjustment (GIA) corrections and degree-1 spherical harmonic (SH) coefficients. We found that erroneous corrections for GIA contaminate GRACE/GFO estimates as time goes forward. Errors in GIA corrections affect degree-1 SH coefficients, and degree-1 errors may also be associated with ocean dynamics. Poor estimates of degree-1 SH coefficients are likely an important source of discrepancies in the two methods of estimating GMOM change.

Feasibility of Magnetic Resonance Fingerprinting on Aging MRI Hardware

The purpose of this work is to evaluate the feasibility of performing magnetic resonance fingerprinting (MRF) on older and lower-performance MRI hardware as a means to bring advanced imaging to the aging MRI install base. Phantom and in vivo experiments were performed on a 1.5T Siemens Aera (installed 2015) and 1.5T Siemens Symphony (installed 2002). A 2D spiral MRF sequence for simultaneous T1/T2/M0 mapping was implemented on both scanners with different gradient trajectories to accommodate system specifications. In phantom, for T1/T2 values in a physiologically relevant range (T1: 195–1539 ms; T2: 20–267 ms), scanners had strong correlation (R2 > 0.999) with average absolute percent difference of 8.1% and 10.1%, respectively. Comparison of the two trajectories on the newer scanner showed differences of 2.6% (T1) and 10.9% (T2), suggesting a partial explanation of the observed inter-scanner bias. Inter-scanner agreement was better when the same trajectory was used, with differences of 6.0% (T1) and 4.0% (T2). Intra-scanner coefficient of variation (CV) of T1 and T2 estimates in phantom were <2.0% and in vivo were ≤3.5%. In vivo inter-scanner white matter CV was 4.8% (T1) and 5.1% (T2). White matter measurements on the aging scanner after two months were consistent, with differences of 1.9% (T1) and 3.9% (T2). In conclusion, MRF is feasible on an aging MRI scanner and required only changes to the gradient trajectory.

Mutagenic Distinction between the Receptor-Binding and Fusion Subunits of the SARS-CoV-2 Spike Glycoprotein and Its Upshot

We observe that a residue R of the spike glycoprotein of SARS-CoV-2 that has mutated in one or more of the current variants of concern or interest, or under monitoring, rarely participates in a backbone hydrogen bond if R lies in the S1 subunit and usually participates in one if R lies in the S2 subunit. A partial explanation for this based upon free energy is explored as a potentially general principle in the mutagenesis of viral glycoproteins. This observation could help target future vaccine cargos for the evolving coronavirus as well as more generally. A related study of the Delta and Omicron variants suggests that Delta was an energetically necessary intermediary in the evolution from Wuhan-Hu-1 to Omicron.

Minority Versus Minority: Partisanship and Inter-Group Competitions Among Asian Americans

Increasingly salient in democratic politics are the divides among political parties regarding how they mobilize supports between ethnic majorities and minorities. Why, then, do some members of a minority group support political parties that seem antithetical to the interests of minority groups? We draw on group conflict theory to suggest that a partial explanation rests on perceived competition within minority groups. We test this theory by focusing on Republican Party support among Asian Americans in the United States. Based on two representative surveys and an original online survey experiment of Asian Americans, we demonstrate that perceived competition among racial minority groups has a significant effect on the partisanship of Asian American and pushes them toward the Republican Party. We also present observational evidence suggesting our theory applies to other minority groups. Our findings provide critical implications on how race affects politics in democracies with increasingly diversified ethnic minority groups.

Justice for the Menopause: A Research Agenda

Menopause is defined by its relationship to menstruation––it is the cessation of menstruation. Medical texts identify menopause as part of the cycle of “decay” associated with female reproductive functions; early menopause is often a dreaded result of various medical treatments and a sign of disfunction. It turns out that only three types of animals experience menopause: killer whales, short-finned pilot whales, and humans, while other animals can reproduce until death. Although the precise relationship between evolutionary theory and the physical development of human menopause is still uncertain, scientists and anthropologists suggest that the “grandmother hypothesis” provides a partial explanation: older women, who can no longer produce their own children, ensure their genetic legacy by playing a critical role in helping to feed, raise, and nurture their grandchildren. The average woman will spend almost as many years “post-menopause” as they will menstruating, and they may spend four years (or more) experiencing perimenopausal symptoms, the transition time between “normal” menstruation and menopause. But legal issues relating to perimenopause, menopause, and post-menopause are just beginning to surface, prompted by the movement towards menstrual justice, feminist jurisprudence, and developments in the law of aging. This Essay is an initial effort to catalogue various legal approaches to menopause and to set out areas for further analysis. It briefly explores cultural images of menopause and post-menopausal women, including the ubiquitous hot flashes; analyzes potential legal claims for menopausal justice; and suggests the interrelationship between such approaches and social attitudes towards menopause. It suggests that “normalizing” menopause––acknowledging its realities––is one means for removing the associated stigma and “disabilities” and might result in reinterpreting existing laws and guiding future legal reforms.

Unplanned but well prepared: A reinterpreted success story of international agricultural research, and its implications

A recent study found that adoption rates of improved chickpea varieties were above 90 per cent in Andhra Pradesh, India. In this paper, we use a novel perspective to reconstruct and attribute how this outcome came about. The accepted success narrative is that the public international agricultural research system developed some excellent new chickpea varieties, which were well suited to local agro-ecologies, farming systems and cropping patterns, and highly appreciated by farmers. We argue that this narrative is incomplete, because it constitutes only a partial explanation of the confluence of factors that led to the outcome. We reconstruct the success story using a recent conceptual framework that decomposes the technological change process into four aspects: propositions, encounters, dispositions and responses (PEDR). We show that many of the factors which contributed to the spread of modern chickpea varieties in Andhra Pradesh lay beyond the control of the international agricultural research system, and operated across large spatial and temporal scales. In conclusion, we argue that the success of improved chickpeas in Andhra Pradesh underscores the value of basic plant breeding and research, which aim to produce public goods. We relate our analysis to current discussions about the future strategic direction of international agricultural research organisations and the CGIAR. Our argument implies a criticism of the drive to develop new varieties which conform to product profiles that are based on predictions of current and near-term demand. While that approach makes sense for product developers seeking to serve commercial markets, basic research is needed to create and diversify technical options, which anticipate a range of future needs that are hard to predict in the present.

Mechanistic ion channel interactions in red cells of patients with Gárdos channelopathy

In patients with Gárdos channelopathy (p.R352H), an increased concentration of intracellular Ca2+ was previously reported. This is a surprising finding because the Gárdos channel (KCa3.1) is a K+ channel. Here, we confirm the increased intracellular Ca2+ for patients with the KCa3.1 mutation p.S314P. Furthermore, we provide the concept of KCa3.1 activity resulting in a flickering of red blood cell (RBC) membranepotential, which activates the CaV2.1 channel allowing Ca2+ to enter the RBC. Activity of the nonselective cation channel Piezo1 modulates the aforementioned interplay in away that a closed Piezo1 is in favor of the KCa3.1-CaV2.1 interaction. In contrast, Piezo1 openings compromise the membrane potential flickering, thus limiting the activity of CaV2.1. With the compound NS309, we mimic a gain-of-function mutation of KCa3.1. Assessing the RBC Ca2+ response by Fluo-4–based flow cytometry and by measuring the membrane potential using the Macey-Bennekou-Egée method, we provide data that support the concept of the KCa3.1/CaV2.1/Piezo1 interplay as a partial explanation for an increased number of high Ca2+ RBCs. With the pharmacological inhibition of KCa3.1 (TRAM34 and Senicapoc), CaV2.1 (ω-agatoxin TK), and Piezo1 (GsMTx-4), we could project the NS309 behavior of healthy RBCs to the RBCs of Gárdos channelopathy patients.

The sustainability of stock price fluctuations: Explanation from a recursive dynamic model

The sustainability of stock price fluctuations indicated by many empirical studies hardly reconciles with the existing models in standard financial theories. This paper proposes a recursive dynamic asset pricing model based on the comprehensive impact of the sentiment investor, the information trader and the noise trader. The dynamic process of the asset price is characterized and a numerical simulation of the model is provided. The model captures the features of the actual stock price that are consistent with the empirical evidence on the sustainability of stock price fluctuations. It also offers a partial explanation for other financial anomalies, for example, asset price’s overreaction, asset bubble and the financial crisis. The major finding is that investor sentiment is the key factor to understand the sustainability of stock price fluctuations.

On generalized Lemaitre–Tolman–Bondi metric: Fractal matter at the end of matter–antimatter recombination

Many recent researches have investigated the deviations from the Friedmannian cosmological model, as well as their consequences on unexplained cosmological phenomena, such as dark matter and the acceleration of the Universe. On one hand, a first-order perturbative study of matter inhomogeneity returned a partial explanation of dark matter and dark energy, as relativistic effects due to the retarded potentials of far objects. On the other hand, the fractal cosmology, now approximated by a Lemaitre–Tolman–Bondi (LTB) metric, results in distortions of the luminosity distances of SNe Ia, explaining the acceleration as apparent. In this work, we extend the LTB metric to ancient times. The origin of the fractal distribution of matter is explained as the matter remnant after the matter–antimatter recombination epoch. We show that the evolution of such a inhomogeneity necessarily requires a dynamical generalization of LTB, and we propose a particular solution.