Secular Shift Research Articles

Current Indications, Trends, and Long-Term Results of 233 Bypasses to Treat Complex Intracranial Aneurysms: A Location-Specific Analysis.

Advances in endovascular flow diverters have led to a secular shift in the management of brain aneurysms, causing debate on current bypass indications. We therefore sought to investigate the long-term results, current indications, and trends of bypasses for brain aneurysms. We retrospectively reviewed bypasses performed between 2005 and 2022 to treat brain aneurysms. Demographic, clinical, and radiological data were collected till the most recent follow-up. Aneurysm occlusion and graft patency was noted on cerebral angiogram in the immediate postoperative, 3-month, and most recent follow-up periods. Clinical outcomes (modified Rankin scores) and complications were assessed at 3 month and most recent follow-up. Trends in bypass volume and graft patency were assessed in 5-year epochs. Results were dichotomized based on aneurysm location to generate location-specific results and trends. Overall, 203 patients (mean age 50 years, 57% female patients) with 207 cerebral aneurysms were treated with 233 cerebral bypasses with a mean follow-up of 2 years. Fusiform morphology was the most common bypass indication. Aneurysm occlusion on immediate postoperative and final follow-up angiogram was 89% (184/207) and 96% (198/207), respectively. Graft patency rate in the immediate postoperative period and most recent follow-up was 95% (222/233) and 92% (215/233), respectively. Of 207 aneurysms, 5 (2%) recurred. Of 203 patients, 81% (165) patients had modified Rankin scores of 0-2 at the 3-month follow-up and 11 patients died (mortality 5%). Although there was a steady decrease in the bypass volume over the study period, the proportion of bypasses for recurrent aneurysms increased serially. Posterior circulation aneurysms had lower rates of aneurysm occlusion and significantly higher incidence of postoperative strokes and deaths (P = .0035), with basilar artery aneurysms having the worst outcomes. Bypass indications have evolved with the inception of novel flow diverters. However, they remain relevant in the cerebrovascular surgeon's armamentarium, and long-term results are excellent.

Paleogene sediment provenance in the Gaize Basin: Implications for early Cenozoic paleogeography of central Tibet

A comprehensive study of the sediment source-to-sink history of basins arranged along the Bangong-Nujiang Suture Zone (BNSZ) is critical for understanding the early Cenozoic topography and drainage systems of central Tibet and its implications for the uplift history of the Tibetan Plateau. Nevertheless, previous provenance analyses work mainly focused on the middle-eastern segment of the BNSZ, those Paleogene basins in the western segment have received less attention, which hinders a full understanding of the early Cenozoic topography of central Tibet. In this study, based on a chronostratigraphic framework developed for the lower Cenozoic continental redbeds of the Gaize Basin, we applied detrital zircon U-Pb geochronology to the well-exposed Paleogene Suonahu Formation in order to reconstruct the basin's source-to-sink history. Integrating these new data with detrital zircon U-Pb results from the underlying Kangtuo Formation, we recognize a major secular shift in sediment provenance characterized by inputs of Lhasa-derived clasts during the Late Eocene. Moreover, we applied statistical analysis to compare the U-Pb age spectra of Eocene strata in the Gaize-Nima-Lunpola basins in order to assess similarities between them and potential source regions. Our study confirms a paleogeographic scenario in which these Paleogene basins most likely were part of a low-elevation intermontane valley.

Covid-19 and the Goalkeeper of the Indian Economy


 The decision and the conviction to keep the capital markets functioning amidst the uncertainty of COVID-19 lockdown, proved to be a game changer for the Indian economy. The robust systems put in place over decades and reinforced with measures to strengthen systemic integrity during COVID, revived the inherent trust in the Indian markets, especially at the retail level. The buoyant numbers of new trading and demat accounts opened, new investors in Mutual Funds etc. are a reflection of this trust. At a structural level, apart from decreasing dependence on FPI investments, the retail segment has witnessed a secular shift from savings to investment. Additionally, within investments, there is a shift from fixed income to equities. This deepening of the investor base has moved the Indian capital market to a higher orbit igniting a structural shift in the economy. 

The Great Start-up Sellout and the Rise of Oligopoly

We document a secular shift from initial public offerings to acquisitions of venture capital-backed start-ups and show that this trend is accompanied by an increase in the opportunity cost of going public over the last quarter-century. Dominant companies that are disproportionately active in the corporate control market for start-ups have become more insulated from the pressures of product market competition over the same period. These facts are consistent with the hypothesis that start-up acquisitions have contributed to rising oligopoly power.

Integral Education in the Context of the Process of Secularization

The purpose of this article is to demonstrate the threat that secularization poses with respect to the education process. The modern time is characterized by a secular shift in social relations and in the very concept of the human person. The paper points explicitly to the consequences of the materialization and technologization of life and proposes an integral education model as an alternative for the increasingly secularized society. Every human being is endowed with personal dignity and inalienable rights whose complete justification can only be uncovered within the context of revealed knowledge. Personality formation, which outlines the general purpose of education, includes not only corporeal and spiritual factors, but also factors of a religious nature that encourage transformation in the sense of achieving ever higher levels of perfection. It is argued that the integral education model can be applied in the areas of learning and work. The touchstone of any human development that takes into account religious factors is humanization, which is defined as making the world more humane in a constant relationship to God.

Evolution of Emerging Markets Debt Investing

1. Chia Liang Lian 1. is the head of Emerging Markets Debt at Western Asset Management in Pasadena, CA. (chialiang.lian{at}westernasset.com) As an asset class, emerging market (EM) debt has undergone a structural evolution to cover more than 70 countries in the past 30 years. One unintended consequence of this asset class’s multifarious attribute is that it is prone to being misunderstood. In this article, the author postulates that for the strategic investor, the nonmonolithic attribute of EMs represents a compelling feature rather than an inherent flaw. The investment proposition for the asset class has witnessed dynamic shifts at different points of the market cycle. During this period, the author suggests that there are three discrete stages of development in the manner by which investors interact with EMs: market access in the 1990s, market boom in the postmillennium decade, and market innovation presently. The author expects a future trend of increased customization to align investment exposures with intended objectives and a secular shift away from an off-the-shelf, index-based approach.

Jumps in stock prices: New insights from old data

We characterize jump dynamics in U.S. stock market returns using a novel series of intraday prices covering almost 90 years. Jump dynamics vary substantially over time. Trends in jump activity relate to secular shifts in the nature of news. Unscheduled news often involving major wars drives jump activity in early decades, whereas scheduled news and especially news pertaining to monetary policy drives jump activity in recent decades. Jump variation measures forecast excess stock market returns, consistent with theory. Results support models featuring a separate jump factor, such that risk premium dynamics are not fully captured by volatility state variables.

Handedness in twins: meta-analyses

BackgroundIn the general population, 10.6% of people favor their left hand over the right for motor tasks. Previous research suggests higher prevalence of atypical (left-, mixed-, or non-right-) handedness in (i) twins compared to singletons, and in (ii) monozygotic compared to dizygotic twins. Moreover, (iii) studies have shown a higher rate of handedness concordance in monozygotic compared to dizygotic twins, in line with genetic factors playing a role for handedness.MethodsBy means of a systematic review, we identified 59 studies from previous literature and performed three sets of random effects meta-analyses on (i) twin-to-singleton Odds Ratios (21 studies, n = 189,422 individuals) and (ii) monozygotic-to-dizygotic twin Odds Ratios (48 studies, n = 63,295 individuals), both times for prevalence of left-, mixed-, and non-right-handedness. For monozygotic and dizygotic twin pairs we compared (iii) handedness concordance Odds Ratios (44 studies, n = 36,217 twin pairs). We also tested for potential effects of moderating variables, such as sex, age, the method used to assess handedness, and the twins’ zygosity.ResultsWe found (i) evidence for higher prevalence of left- (Odds Ratio = 1.40, 95% Confidence Interval = [1.26, 1.57]) and non-right- (Odds Ratio = 1.36, 95% Confidence Interval = [1.22, 1.52]), but not mixed-handedness (Odds Ratio = 1.08, 95% Confidence Interval = [0.52, 2.27]) among twins compared to singletons. We further showed a decrease in Odds Ratios in more recent studies (post-1975: Odds Ratio = 1.30, 95% Confidence Interval = [1.17, 1.45]) compared to earlier studies (pre-1975: Odds Ratio = 1.90, 95% Confidence Interval = [1.59–2.27]). While there was (ii) no difference between monozygotic and dizygotic twins regarding prevalence of left- (Odds Ratio = 0.98, 95% Confidence Interval = [0.89, 1.07]), mixed- (Odds Ratio = 0.96, 95% Confidence Interval = [0.46, 1.99]), or non-right-handedness (Odds Ratio = 1.01, 95% Confidence Interval = [0.91, 1.12]), we found that (iii) handedness concordance was elevated among monozygotic compared to dizygotic twin pairs (Odds Ratio = 1.11, 95% Confidence Interval = [1.06, 1.18]). By means of moderator analyses, we did not find evidence for effects of potentially confounding variables.ConclusionWe provide the largest and most comprehensive meta-analysis on handedness in twins. Although a raw, unadjusted analysis found a higher prevalence of left- and non-right-, but not mixed-handedness among twins compared to singletons, left-handedness was substantially more prevalent in earlier than in more recent studies. The single large, recent study which included birth weight, Apgar score and gestational age as covariates found no twin-singleton difference in handedness rate, but these covariates could not be included in the present meta-analysis. Together, the secular shift and the influence of covariates probably make it unsafe to conclude that twinning has a genuine relationship to handedness.

What’s new with the oldest form of brain stimulation: Innovations in ECT

Abstract The practice of electroconvulsive therapy (ECT) continues to evolve. Changes in the nature of electrical stimulation and in intracerebral current paths have markedly reduced or eliminated ECT’s adverse cognitive side effects, while maintaining its effectiveness. Further improvements in the nature of electrical stimulation will likely involve titrating in the current domain to minimize individual differences in intracranial current density. Improvements in spatial targeting, using magnetic seizure therapy (MST) or focal electrically administered seizure therapy (FEAST), promise to further dissociate therapeutic and adverse effects, and are presently undergoing pivotal trials. The key clinical challenges facing ECT pertain to two issues: when and how to change ECT treatment technique in patients who show inadequate or slow benefit, and optimal methods for enhancing durability of benefit and reducing relapse risk. New research suggests that ECT is routinely terminated prematurely in many depressed patients resulting in unnecessarily reduced remission rates. It will be suggested that there has been a secular shift in ECT practice, where the modal patient currently receives considerably more treatments than in the past. In recent years, it has been demonstrated that ECT results acutely in widespread increases in grey matter volume. The implications of these findings will be briefly discussed. Keywords: electroconvulsive therapy, FEAST, MST, depression

A Secular Shift of the Madden‐Julian Oscillation and Its Relation to Western Pacific Ocean Warming

AbstractIn the context of global warming, understanding changes in the Madden‐Julian Oscillation (MJO) is of great importance, because of its worldwide impact on surface weather and climate. By analyzing the temporal evolution of the phase relationship between Kelvin waves and the MJO, we find a secular phase shift of the MJO after year 2000, at which the MJO exhibits an eastward extension over the Maritime Continent and the Western Pacific Ocean. Further, we examine the influence of sea surface temperature (SST) variations on the anomalous convection and Kelvin waves, and demonstrate that the recent warming trend of the Western Pacific SST is a factor causing the changes of the MJO over this region. The results deepen our understanding of recent modeling and observational studies about the changes of the MJO and confirm the enhanced activity of the MJO over the past few decades.

Fractionation of rhenium isotopes in the Mackenzie River basin during oxidative weathering

Rhenium (Re) is a trace element whose redox chemistry makes it an ideal candidate to trace a range of geochemical processes. Here, we report the first rhenium isotopic measurements (δ187Re) from river-borne materials to assess the influence of chemical weathering on Re isotopes at continental scale. The δ187Re was measured in water, suspended sediments and bedloads from the Mackenzie River and its main Arctic tributaries in Northwestern Canada. We find that the δ187Re (relative to NIST SRM 989) of river waters ranges from −0.05‰ to +0.07‰, which is generally higher than the corresponding river sediment (−0.25‰ to +0.01‰). We show that the range of δ187Re in river sediments (∼0.30‰) is controlled by a combination of source bedrock isotopic variability (provenance) and modern oxidative weathering processes. After correcting for bedrock variability, the δ187Re of solids appear to be positively correlated with the amount of Re depletion related to oxidative weathering. This correlation, and the offset in δ187Re between river water and sediment, can be explained by preferential oxidation of reactive phases with high δ187Re (i.e. rock organic carbon, sulfide minerals), but could also result from fractionation during oxidation or the influence of secondary weathering processes. Overall, we find that both basin-average bedrock δ187Re (∼−0.05‰) and dissolved δ187Re (∼−0.01‰) in the Mackenzie River are lower than the δ187Re of Atlantic seawater (+0.12‰). These observations provide impetus for future work to constrain the Re isotope mass balance of seawater, and assess the potential for secular shifts in its δ187Re values over time, which could provide an additional isotopic proxy to trace current and past redox processes at Earth's Surface.

The history of ground ice at Jezero Crater Mars and other past, present, and future landing sites

Shallow subsurface water ice on Mars is currently stable poleward of about 45° latitude and unstable in the equatorial regions. Past climate cycles driven by orbital oscillations are expected to result in significant changes to this distribution of ground ice over geologic history. In the present study we model the 2.5-Myr history of ground ice at 11 past, present, and planned future landing sites, employing new views of the martian climate and new ground truth observations. We specifically evaluate the potential for detecting ground ice at current and future GPR-equipped-rover landing sites at Jezero Crater, Utopia Planitia, and Oxia Planum. We find that, while ground ice is stable at the past Phoenix and Viking Lander 2 sites, it is presently unstable at all others. However, ground ice would have been stable at all the landing sites for extended periods of 10's of kyrs when the obliquity exceeded about 29°–33°. The most recent such episode would have occurred about 500 kyrs ago. On thousand-year time scales water-vapor diffusion through porous soil and ice condensation are rapid enough to keep pace with these climate changes, such that the presence of ground ice can be equated with its stability. Prior to 5 Myr ago the obliquity is predicted to have experienced a secular shift to a higher average of ~36°. During this time extensive subsurface ice deposits may have formed that may persist unstably today as a relict of this past condition.

Arid Coastal Carbonates and the Phanerozoic Record of Carbonate Chemistry

AbstractOcean chemistry and carbonate sedimentation link Earth's climate, carbon cycle, and marine pH. The carbonate system in seawater is complex and there are large uncertainties in key parameters in deep time. Here, we link sedimentary textures formed in arid coastal environments and preserved in the rock record to past seawater carbonate chemistry. Prior to the mid‐Mesozoic, tepee structures and pisoids – features associated with peritidal environments – co‐vary with available shelf area during cycles of supercontinent formation and rifting. In contrast, tepees and pisoids are consistently scarce after the mid‐Mesozoic, which coincides with a radiation in pelagic calcifiers as well as the breakup of Pangea. Numerical models suggest that the global and temporal abundances of tepee structures and pisoids are correlated with secular shifts in seawater chemistry, and that trends likely reflect the underlying influence of tectonics and biotic innovation on marine alkalinity and the saturation states of carbonate minerals. As independent sedimentary proxies, tepees and pisoids serve as benchmarks for global carbon cycle models and provide a new proxy record of seawater chemistry that can help discern links among tectonics, biotic innovation, and seawater chemistry.

A secular shift in Carolingian history writing?

This article explores a series of Carolingian historians, writing in the early ninth century, who marginalized the role of God’s agency, in sharp contrast to the pattern established by the Annales Regni Francorum. Where this has been noted before, largely in relation to Einhard’s Vita Karoli, it has been explained either as a clash between lay and monastic ideals or as a by‐product of the classical renewal at the Carolingian court. Examining this process across multiple texts suggests, however, that these historians can be understood as self‐consciously ‘secularizing’ in response to contemporary crises.

Earnings Inequality and Dynamics in the Presence of Informality: The Case of Brazil

Using a combination of rich administrative and household survey data, we document a series of new facts on earnings inequality and dynamics in a developing country with a large informal sector: Brazil. Since the mid-1990s, both inequality and volatility of earnings have declined significantly in Brazil's formal sector. Higher-order moments of the distribution of earnings innovations show similar cyclical movements in Brazil as in developed countries like the U.S. Earnings mobility is comparatively high, especially at the bottom of the distribution. Compared to the formal sector, earnings are more volatile in the informal sector. Workers who switch between sectors experience earnings innovations that have a positive mean and are positively skewed when moving to the formal sector but have a negative mean and are negatively skewed when moving to the informal sector. A secular shift of employment toward the less volatile formal sector since the early 2000s has contributed to a decline in the economy-wide volatility of earnings.

Decline in internal migration levels in Australia: Compositional or behavioural effect?

AbstractLevels of internal migration have declined since the 1980s in many advanced economies. Australian studies remain largely descriptive, making it difficult to ascertain the extent to which the decline in aggregate levels of migration is due to shifts in the socio‐demographic composition of the Australian population or driven by deeper behavioural changes. This paper aims to address this gap by applying an Oaxaca‐Blinder decomposition method to individual‐level data from the 2001 and 2016 censuses. Our results confirm the strong impact of population ageing on the decline in migration although its effect has been fully counteracted by other compositional changes such as education and immigration. We find behavioural effects to be the principal factor explaining this downward trend. This finding points to a secular shift in migration behaviour and represents a starting point in developing a more comprehensive understanding of the factors underpinning the long‐term decline in internal migration in Australia.

Size and Investment Performance: Defined Benefit vs. Defined Contribution Pension Plans

Using a comprehensive sample of over 160 thousand U.S. private pension plans, we find significant economies of scale in investment performance and administrative expenses that are more prominent for defined benefit (DB) than for defined contribution (DC) plans. Small DB plans underperform size-matched DC plans and face the highest termination probability, and the majority of both types underperform passive benchmarks. Small plans and small sponsors prefer the DC structure more strongly than large ones do. Our results highlight the inefficiency of small DB plans, which is consistent with the secular shift toward DC plans and the recent trend of consolidation.

The changing temporal association between caesarean birth and neonatal death in Ethiopia: secondary analysis of nationally representative surveys

ObjectiveTo examine the changing temporal association between caesarean birth and neonatal death within the context of Ethiopia from 2000 to 2016.DesignSecondary analysis of Ethiopian Demographic and Health Surveys.SettingAll administrative regions...

Assessment of coupled regional climate model (RegCM4.6–CLM4.5) for Indian summer monsoon

A model experiment with a regional climate model (RegCM4.6) coupled with an updated land–surface scheme (Community Land Model; CLM4.5) is integrated for 34 years to study the Indian summer monsoon (ISM). An eastward shift (towards Bay of Bengal; BoB) in simulated monsoon features due to the secular shift of the moist convective systems is observed. Further diagnostics show lower temperature over India as compared to BoB; while the Findlater jet is significantly weakened over the Arabian Sea. The low-pressure drags the southwesterly towards BoB through India. The Bowen ratio and evaporation reflect less soil moisture availability over the land. The analysis of simulated omega, moist static energy and Hadley circulation illustrates that an atmospheric condition dominates over land which further suppresses the convection and hence the rainfall. However, favorable atmospheric condition supporting convection and moisture availability leads to heavy precipitation over BoB and hence causes the eastward shift in simulated ISM rainfall. The convective fraction contributes the major share to the total precipitation. An evaluation of appropriate land surface spin-up period in order to investigate the optimum stabilization period for CLM4.5, indicates a possible weak coupling between land and atmosphere components in model simulation. This led to the improper energy and moisture exchanges between land and atmosphere in the simulation. The present work also suggests that, the simulated mean rainfall is not predominantly influenced by the length of different spin-up periods (up to 25 years) in case of weak coupling of land and atmosphere.

A paleosol record of the evolution of Cr redox cycling and evidence for an increase in atmospheric oxygen during the Neoproterozoic.

Atmospheric oxygen levels control the oxidative side of key biogeochemical cycles and place limits on the development of high-energy metabolisms. Understanding Earth's oxygenation is thus critical to developing a clearer picture of Earth's long-term evolution. However, there is currently vigorous debate about even basic aspects of the timing and pattern of the rise of oxygen. Chemical weathering in the terrestrial environment occurs in contact with the atmosphere, making paleosols potentially ideal archives to track the history of atmospheric O2 levels. Here we present stable chromium isotope data from multiple paleosols that offer snapshots of Earth surface conditions over the last three billion years. The results indicate a secular shift in the oxidative capacity of Earth's surface in the Neoproterozoic and suggest low atmospheric oxygen levels (<1% PAL pO2 ) through the majority of Earth's history. The paleosol record also shows that localized Cr oxidation may have begun as early as the Archean, but efficient, modern-like transport of hexavalent Cr under an O2 -rich atmosphere did not become common until the Neoproterozoic.