Periods Of High Activity Research Articles

Physiological and pathological evidence of O-GlcNAcylation regulation during pregnancy related process

O-GlcNAcylation is a dynamic and reversible post-translational modification (PTM) controlled by the enzymes O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Changes in its expression lead to a breakdown in cellular homeostasis, which is linked to several pathological processes. Placentation and embryonic development are periods of high cell activity, and imbalances in cell signaling pathways can result in infertility, miscarriage, or pregnancy complications. O-GlcNAcylation is involved in cellular processes such as genome maintenance, epigenetic regulation, protein synthesis/degradation, metabolic pathways, signaling pathways, apoptosis, and stress response. Trophoblastic differentiation/invasion and placental vasculogenesis, as well as zygote viability and embryonic neuronal development, are all dependent on O-GlcNAcylation. This PTM is required for pluripotency, which is a required condition for embryonic development. Further, this pathway is a nutritional sensor and cell stress marker, which is primarily measured by the OGT enzyme and its product, protein O-GlcNAcylation. Yet, this post-translational modification is enrolled in metabolic and cardiovascular adaptations during pregnancy. Finally, evidence of how O-GlcNAc impacts pregnancy during pathological conditions such as hyperglycemia, gestational diabetes, hypertension, and stress disorders are reviewed. Considering this scenario, progress in understanding the role of O- GlcNAcylation in pregnancy is required.

Predicting Bond Return Predictability

This paper provides empirical evidence on predictable time variations in out-of-sample bond return predictability. Bond return predictability is associated with periods of high (low) economic activity (uncertainty), which implies that violations of the expectations hypothesis are state dependent and linked to features of the business cycle. These state dependencies in predictability, established by introducing a new multivariate test for equal conditional predictive ability, can be used in real time to improve out-of-sample bond risk premia estimates and investors’ economic utility through a novel dynamic forecast combination scheme that uses predicted forecasting performance to identify the best set of methods to include in the combined forecast. Dynamically combined forecasts exhibit strong countercyclical behavior and peak during recessions.This paper was accepted by Lukas Schmid, finance.Funding: This work was supported by the Danish Council of Independent Research [Grants DFF 7024–00020B and DFF 9033–00003B] and the Danish Finance Institute.Supplemental Material: The data files and online appendices are available at https://doi.org/10.1287/mnsc.2023.4713 .

Effect of geomagnetic activity on investors and managers: evidence from the pricing and timing of disclosure of earnings news

PurposeThis paper's purpose was to examine the impact of geomagnetic activity (GMA) on the timing and valuation of earnings information disclosed by firms every quarter.Design/methodology/approachThe authors start the analyses with a sample of 112,669 client firms from 1989 to 2018. To analyze the impact of GMA on the earnings response coefficient (ERC), the authors use the three-day cumulative abnormal returns and cumulative abnormal returns for the extended post-earnings announcement window [2, 75] as the dependent variables. The authors interact unexpected earnings (UE) with the C9 Index, an index commonly used to measure GMA and study how GMA affects the pricing of new public information. To examine the effect of GMA on the timing of disclosure of earnings news, the authors regress a variant of the GMA index on the propensity to disclose bad earnings news.FindingsThe authors find significantly lower earnings response coefficients during periods of high GMA. This effect is permanent and stock prices do not correctly incorporate the implications of earnings information over time. The authors also show that managerial behavior is affected by GMA as well and the managers are more (less) likely to release bad (good) news during periods of higher activity. Finally, the authors also find that in situations where stakeholders are likely to rely on modern technology that depends minimally on humans, the adverse impact of GMA on the pricing of earnings information is mitigated.Originality/valueThe literature on the effect of GMA on the capital market is very limited and focuses primarily on stock returns, while the behavioral finance literature focuses on circumstances like weather, temperature and sporting outcome to study how the investors' mood affects their capital market behavior. The authors add to both the literature by investigating how GMA influences investors' and managers' behaviors in the capital market.

Two gates mediate NMDAR activity and are under subunit-specific regulation.

NMDA receptors (NMDAR) are ionotropic glutamate receptors that mediate fast synaptic transmission and synaptic plasticity. Dysfunction of NMDARs has been found in numerous neurological diseases including Alzheimer's disease, Intellectual disability, epilepsy, autism, and schizophrenia. The NMDARs broad role in neuronal function is reflected in the complexity of its opening and closing kinetics, which can be broadly divided into periods of high opening activity, or clusters, interspersed by periods of no activity, or inter clusters. The initial step in ion channel opening is binding of agonists to the ligand-binding domain (LBD), which generates free energy that propagates to the ion channel to open ‘gate(s)’. NMDARs are heterotetramers composed of the obligate GluN1 and typically some combination of GluN2 subunits. The ion channel pore consists of two transmembrane segments (M1 and M3), a reentrant pore loop (M2) and a peripheral M4. A conserved glycine in the outer most transmembrane helix, the M4 helix, plays important roles in regulating NMDAR function. Here we find that these glycines play different roles in regulating channel opening. The GluN1 glycine mainly regulates single channel events within a cluster or bursts of activity, whereas GluN2A glycine mainly regulates opening into and out of clusters. Molecular dynamic simulations suggest that the GluN1 M4 regulates a ‘gate’ at the M2 loop, whereas the GluN2 M4 (along with GluN2 pre-M1) regulates a gate at the M3 helix bundle crossing. Subsequent functional experiments support this interpretation, leading to the hypothesis that the distinct kinetics of NMDARs are mediated by two gates that are under subunit-specific regulation. These results indicate that the GluN2A subunit regulates early steps in the gating process whereas the GluN1 regulate later steps including transitions form short to long-lived open states.

Investigating the Applicability of Ichthyoplanktonic Indices in Better Understanding the Dynamics of the Northern Stock of the Population of Atlantic Hake Merluccius merluccius (L.)

Abundance indices are essential data for the application of stock assessment models to obtain fish abundance estimates. Abundance indices have usually been derived from fishery-dependent data, yet the increase in fisheries-independent surveys is now offering new opportunities for these calculations. In this study, we explored the usefulness of ichthyoplankton indices derived from scientific surveys in estimating spawning biomass. In addition, we also investigated whether the strength of the year–class of the commercial cohort of Atlantic hake, as a determinant, could be defined at an early life stage. We used samples collected during the triennial mackerel and horse mackerel egg surveys (MEGS), which cover the hake spawning area in the Bay of Biscay. The biomass indices were determined as the abundance of eggs in the early development stage (stage 1) when transformed into egg production (EP) from 1995 to 2019 in the months of March and April—which is considered a period of high spawning activity for hake in this area. Additionally, we built a metric for larval abundance and converted larval length into age. This was in addition to constructing a pre-recruit year-class index (YCI) while using the EVHOE bottom trawl abundance database for hake for the period of 1997 to 2016. The results of regression analysis of egg production and spawning stock biomass indicate that both parameters are significantly correlated (r = 0.76). By connecting the abundance of eggs and larvae in the adjoining stages, we are able to identify two periods of high mortality associated with the transition from “yolk-sac-first” to “feeding larvae” and “late larvae-YCI10”, but we were unable to discover when the strength of the recruitment year–class is determined. As such, it appears that for the northern stock of hake, recruitment is established in the late juvenile stages.

Markers of lithogenic activity in kidney stone disease

Kidney stones develop silently . Several markers revealing the activation of lithogenic process were proposed . Here we review the technologies behind these diagnostic tests and describe six groups of lithogenic activity markers : 1) indices and calculated supersaturations , based on concentration of stone forming and inhibiting ions in 24h-urine; 2) macromolecules or specific molecules in urine ; 3) urine physical properties , 4) blood markers ; 5) instrumental methods ; 6) induced urinary crystal formation tests . The induced urinary crystal formation group is the most promising and successful . These tests can be used for revealing the periods of high lithogenic activity and guiding prompt treatment intensification . Convenient and affordable markers of lithogenic activity , applied regularly and remotely , make effective personalized recurrence prevention programs feasible .

Association of nurse staffing and unit occupancy with mortality and morbidity among very preterm infants: a multicentre study

ObjectiveIn a healthcare system with finite resources, hospital organisational factors may contribute to patient outcomes. We aimed to assess the association of nurse staffing and neonatal intensive care unit (NICU)...

Динамика самоопределения этнических движений на постсоветском пространстве (на примере Азербайджана и Грузии)

Introduction: the modern world includes a variety of self-determination movements, many of which have grown into large-scale political-territorial conflicts that continue to this day. The post-Soviet countries provide illustrative examples of this kind of movements. Objectives: to identify variability in the development trajectories of self-determination movements in Georgia and Azerbaijan. Methods: case-study, comparable-case method: five movements advocating self-determination of ethnic groups are analysed (three movements define themselves in interaction with the Georgian state, two – with the Azerbaijani one). Results: the research has revealed that the basis of self-determination movements is ethnic identity. Three cases have been identified to demonstrate similar dynamics: the Karabakh, Abkhaz and South Ossetian movements are involved in a recurring conflict for self-determination and are examples of successful movements. Two cases – the Adjarian and Talysh movements showed a decline in dynamics and a gradual extinction. Conclusions: the period of high activity and success in self-determination was the first half of the 1990s, when Azerbaijan and Georgia were going through systemic transformations and the formation of their own statehood. Further, their intentions to restore governability and maintain territorial integrity clashed with the will of movements for self-determination and self-government. Support from Russia or a kin-state of an ethnic minority also affects the dynamics of the confrontation. The development trajectory of the movements is determined by the dynamic balance of opposing forces.

Virgin queen behaviour and controlled mating in the stingless bee Tetragonulacarbonaria (Meliponini)

Improving knowledge of virgin queen behaviour and mating biology in stingless bees (Meliponini) is an important step towards artificial selection programmes for managed colonies. Here we study the Australian stingless bee Tetragonulacarbonaria to (1) describe the behaviour of queens from eclosion until egg-laying, and (2) assess whether young queens can be reared and mated under constrained conditions. We extracted mature virgin queen cells of T.carbonaria from large colonies and reared them in queen maturation boxes containing a limited number of workers (“micro-colonies”). Queen behaviour followed a typical pattern with three phases: a period of high activity and wing-flapping on top of the brood (5 ± 2 days of age), attempts to leave the colony for the nuptial flight (12 ± 3 days of age), and oviposition (20 ± 6 days of age). In total, 71% (68 of 95) of queen cells hatched in our maturation boxes and 57% (39 of 68) survived to mating age, with some observed to be actively killed by workers within the first week of life (8 of 68; 11%). For a subset of our queens, we performed controlled matings (either with or without CO2 narcosis) by presenting constrained females to males in mating aggregations, allowing one male to mate (deposit mating plug) and then returning queens to their box. In the absence of CO2 narcosis, 30% of queens mated this way were subsequently found to have sperm in their spermathecae, indicative of a successful mating (5 of 17). The remaining 70% however contained no sperm, despite the presence of the male mating plug. Amongst queens that were CO2 narcotized before and during the controlled mating, none had sperm in their spermathecae (0 of 12), though most went on to activate their ovaries following the mating and lay male (haploid) eggs. Together, these trials indicate that controlled matings with T.carbonaria are possible, but suggest that queens may need to actively accept mating for successful sperm transfer.

Increasing connections among temporal invariability, resistance and resilience of alpine grasslands on the Tibetan Plateau

Ecological stability contains multiple components, such as temporal invariability, resistance and resilience. Understanding the response of stability components to perturbations is beneficial for optimizing the management of biodiversity and ecosystem functioning. Although previous studies have investigated the effects of multiple perturbations on each stability component, few studies simultaneously measure the multiple stability components and their relationships. Alpine grasslands on the Tibetan Plateau are exposed to co-occurring perturbations, including climate change and human activities. Here, we quantified three stability components (temporal invariability, resistance, and resilience) of alpine grasslands on the Tibetan Plateau during periods of high (2000-2008) and low (2009-2017) human activity intensity, respectively. We focused on the effects of climate variables (temperature, precipitation, radiation) and human activities (grazing intensity) on covariation among stability components. The results show that (1) for periods of high and low human activity, temporal invariability was positively correlated with resistance and resilience, while resistance was independent of resilience; (2) the dimensionality of alpine grasslands decreased by almost 10%, from 0.61 in the first period to 0.55 in the second period, suggesting the increasing connections among temporal invariability, resistance and resilience of alpine grasslands; and (3) temperature but not grazing intensity dominated the changes in the dimensionality of stability. These findings improve our understanding of multi-dimensional stability and highlight the importance of climate variability on alpine grassland stability on the Tibetan Plateau.

A simple two-state model interprets temporal modulations in eruptive activity and enhances multivolcano hazard quantification.

Volcanic activity typically switches between high-activity states with many eruptions and low-activity states with few or no eruptions. We present a simple two-regime physics-informed statistical model that allows interpreting temporal modulations in eruptive activity. The model enhances comprehension and comparison of different volcanic systems and enables homogeneous integration into multivolcano hazard assessments that account for potential changes in volcanic regimes. The model satisfactorily fits the eruptive history of the three active volcanoes in the Neapolitan area, Italy (Mt. Vesuvius, Campi Flegrei, and Ischia) which encompass a wide range of volcanic behaviors. We find that these volcanoes have appreciably different processes for triggering and ending high-activity periods connected to different dominant volcanic processes controlling their eruptive activity, with different characteristic times and activity rates (expressed as number of eruptions per time interval). Presently, all three volcanoes are judged to be in a low-activity state, with decreasing probability of eruptions for Mt. Vesuvius, Ischia, and Campi Flegrei, respectively.

Heterogeneity of Stroke in Patients with Systemic Lupus Erythematosus.

Objective The underlying pathophysiology varies according to stroke subtype. However, stroke heterogeneity among patients with systemic lupus erythematosus (SLE) remains unstudied. We hypothesized that the contribution of SLE to stroke might vary according to its subtype and investigated the associations of SLE and various stroke subtypes. Methods Diagnostic codes and electronic medical records were used to identify 70 patients with SLE who developed acute cerebral infarction or intracerebral hemorrhaging at four tertiary referral hospitals between 2008 and 2018. Intracerebral hemorrhaging was classified as lobar or deep, while cerebral infarction was classified according to the SSS-TOAST criteria. Physician notes were used to identify SLE activity, and their prevalences were compared among stroke subtypes. Outcomes were collected from the patients' medical records. Results The most common stroke subtype in patients with SLE was that of undetermined causes (31%), followed by small artery occlusion (16%), cardioaortic embolism (13%), other causes (11%), lobar hemorrhaging (10%), deep hemorrhaging (10%), and large artery atherosclerosis (9%). Stroke onset occurred during a period of high SLE activity in 21 patients (30%). The proportion of patients with high SLE activity varied according to stroke subtype (p=0.039) and was highest for cerebral infarction with undetermined causes. Stroke recurrence or death was observed in 40% of patients within 5 years after the initial stroke onset. Conclusion The contributions of SLE to stroke varied significantly according to the stroke subtype. Given the unfavorable prognosis, close stroke subtype-specific observation by rheumatologists and stroke specialists is recommended after stroke events.

Trading and liquidity in the catastrophe bond market

AbstractWe provide first insights into secondary market trading, liquidity determinants, and the liquidity premium of catastrophe bonds. Based on transaction data from TRACE (Trade Reporting and Compliance Engine), we find that cat bonds are traded less frequently during the hurricane season and more often close to maturity. Trading activity indicates that the market is dominated by brokers without a proprietary inventory. Liquidity is high in periods of high trading activity in the overall market and for bonds with low default risk or close to maturity, which results from lower order processing costs. Finally, using realized bid–ask spreads as a liquidity measure, we find that on average, 21% of the observable yield spread on the cat bond market is attributable to the liquidity premium, with a magnitude of up to 141 bps for high‐risk bonds.

Exploring the variability of the venusian thermosphere with the IPSL Venus GCM

Recent simulations of the Institut Pierre-Simon Laplace (IPSL) Venus Global Climate Model (VGCM) developed at the Laboratoire de Météorologie Dynamique (LMD) were performed with a model top raised from ∼10−5 (∼150 km) to ∼10−8 Pa (180–250 km; upper boundary). The parameterizations of non-LTE CO2 near infrared heating rates and of non-orographic gravity waves were improved. In addition, a tuning of atomic oxygen production was introduced to improve related effects (heating and cooling) and resulting thermospheric number densities. This work focusses on validating the modelled thermospheric structure using data from the Pioneer Venus, Magellan and Venus Express missions which cover similar and complementary (equator and pole) regions at different periods of solar activity, typically above altitudes of 130 km. This version of the IPSL VGCM shows good agreement with the diurnal evolution of the exospheric temperature at the equator reconstructed from the atomic oxygen scale height of the Pioneer Venus Orbiter Neutral Mass Spectrometer data. The model is also able to reproduce the sensitivity of the exospheric temperature and species density to the EUV flux of the solar high activity period (from 180 to 230 solar flux unit; s.f.u). However, to fit with the PV-ONMS density observations, it was necessary to increase the photodissociation of CO2 into CO and O above 135 km by a factor of 10. Indeed, our study points to the importance of an additional source of oxygen and carbon monoxide production above 130 km other than CO2 photolysis to explain the vertical profiles of CO and O number density in the thermosphere. Moreover, the presence of a GW drag at altitudes above 140 km has a significant impact on the nightside temperature value and its distribution.

NON-VOLANT MAMMALS OF THE SERRA DA MACACA PARK ROAD (SP-139), SOUTHEASTERN BRAZIL

The objective of this study was to survey non-volant mammals at Serra da Macaca Park Road (SP-139), particularly during road daily closure. Visual searches and camera traps were used to record mammals, and estimator Jackknife to estimate the expected richness. Differences in diversity were calculated using the Shannon-Wiener index (H’). In total, 12 species of non-volant mammals, four of them considered threatened, were sampled. Additionally, roadkills of the non-volant mammals were recorded too. The absence of some predominantly nocturnal species from the list of the roadkilled non-volant mammals was noticeable. The results highlight the importance of the temporary road closures, during periods of high mammal activity.

Sharing the load: Contagion and tolerance of mood in social networks.

The relations between self and others are fluid and constantly changing but exert a profound influence on our identity and emotional experiences. Indeed, human emotions are frequently and intensely social, and the people with whom we interact can alter our momentary mood. But does emotional "contagion" extend over prolonged periods of hours to days, and, if so, how does it propagate through interconnected groups? Answering this question is empirically challenging, because mood similarity in connected individuals can arise through multiple mechanisms (social influence, social selection, and shared external causation), making causal inferences hard to draw. We address this challenge using temporally high-resolution, longitudinal data from 2 independent, bounded social networks during periods of high communal activity and low external contact. Adolescent study participants (N = 79) completed daily mood (n = 4,724) and social interaction (n = 1,775) ratings during residential performance tours of classical music lasting 5 to 7 days. Analyses using statistical network models show that in both networks, adolescent musicians became reciprocally more similar in mood to their interaction partners. The observed contagion effect was greater for negative than for positive mood. That is, although one may catch a friend's bad mood, the friend may feel less negative in the process. These results suggest a mechanism for emotional buffering and the cost of social support. We found no evidence for social selection based on mood. Indeed, participants were remarkably tolerant of their peers' mood fluctuations and showed no evidence of altering their patterns of social interaction accordingly. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

JUSTIFICATION OF THE PARAMETERS OPTIMIZATION OF THE ENTERPRISE'S CASH FLOWS

Cash flow management is a key aspect of an enterprise's activity, as it is used to regulate all spheres of activity of a business entity, therefore issues related to the effectiveness of this process are of great relevance. The article substantiates the theoretical basis, develops a methodical approach and practical proposals for improving the cash flow management system. The object of the study was the company's cash flow management processes. The subject of scientific research was the theoretical, methodical and applied aspects of cash flow management of the enterprise, as well as modern methods of its optimization. An economic-mathematical model of multi-game optimization of the company's cash flows has been developed, which allows you to accumulate the necessary stock of cash assets in periods of high business activity and direct them in such a way that planned and necessary payments are made during the period of shortage of funds. The main criterion of the proposed model of cash flow optimization is the maximization of net cash flow from operating activities, which should ensure the development and expansion of the enterprise's activities on the basis of self-financing due to the growth of the areas of activity. According to the proposed model, the optimal balance of cash assets, insurance, compensation and current stock of cash assets for a specific enterprise is determined. The proposed model makes it possible to accumulate the necessary stock of monetary assets in periods of high business activity and to direct them in such a way that in the period of shortage of funds, planned and necessary payments are made, as a result of the implementation of the model, it becomes possible to avoid attracting credit resources and related expenses, while receiving additional profit from investing temporarily free funds. The information base of the study was made up of the fundamental theoretical provisions of economic science in the field of enterprise cash flow management, researched in the works of outstanding domestic and foreign economists, legislative and regulatory acts of Ukraine, government decisions and resolutions, N(S)BO, P(S)BO, financial reporting of Urozhai LLC.

Daily 1 km terrain resolving maps of surface fine particulate matter for the western United States 2003–2021

We developed daily maps of surface fine particulate matter (PM2.5) for the western United States. We used geographically weighted regression fit to air quality station observations with Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth (AOD) data, and meteorological data to produce daily 1-kilometer resolution PM2.5 concentration estimates from 2003–2020. To account for impacts of stagnant air and inversions, we included estimates of inversion strength based on meteorological conditions, and inversion potential based on human activities and local topography. Model accuracy based on cross-validation was R2 = 0.66. AOD data improve the model in summer and fall during periods of high wildfire activity while the stagnation terms capture the spatial and temporal dynamics of PM2.5 in mountain valleys, particularly during winter. These data can be used to explore exposure and health outcome impacts of PM2.5 across spatiotemporal domains particularly in the intermountain western United States where measurements from monitoring station data are sparse. Furthermore, these data may facilitate analyses of inversion impacts and local topography on exposure and health outcome studies.

Variability of Precipitation Recycling and Moisture Sources over the Colombian Pacific Region: A Precipitationshed Approach

This study assessed the precipitation recycling and moisture sources in the Colombian Pacific region between 1980–2017, based on the monitoring of moisture in the atmosphere through the Eulerian Water Accounting Model-2 layer (WAM2 layer) and the delimitation of the area contributing to terrestrial and oceanic moisture in the region is performed using the “precipitationshed” approach. The results indicate a unimodal precipitation recycling ratio for the North and Central Pacific and Patía-Mira regions, with the highest percentages between March and April, reaching 30% and 34%, respectively, and the lowest between September and October (between 19% and 21%). Moreover, monthly changes in the circulation of the region promote a remarkable variability of the sources that contribute to the precipitation of the study area and the spatial dynamics of the precipitationshed. From December to April, the main contributions come from continental sources in eastern Colombia and Venezuela, the tropical North Atlantic, and the Caribbean Sea, a period of high activity of the Orinoco Low-Level jet. In September, the moisture source region is located over the Pacific Ocean, where a southwesterly cross-equatorial circulation predominates, converging in western Colombia, known as the Choco Jet (CJ), decreasing the continental contribution. An intensified Caribbean Low-Level Jet inhibits moisture sources from the north between June and August, strengthening a southerly cross-equatorial flow from the Amazon River basin and the southeastern tropical Pacific. The March–April (September–October) season of higher (lower) recycling of continental precipitation is related to the weakening (strengthening) of the CJ in the first (second) half of the year, which decreases (increases) the contribution of moisture from the Pacific Ocean to the region, increasing (decreasing) the influence of land-based sources in the study area.

Modelling the modulation of cortical Up-Down state switching by astrocytes.

Up-Down synchronization in neuronal networks refers to spontaneous switches between periods of high collective firing activity (Up state) and periods of silence (Down state). Recent experimental reports have shown that astrocytes can control the emergence of such Up-Down regimes in neural networks, although the molecular or cellular mechanisms that are involved are still uncertain. Here we propose neural network models made of three populations of cells: excitatory neurons, inhibitory neurons and astrocytes, interconnected by synaptic and gliotransmission events, to explore how astrocytes can control this phenomenon. The presence of astrocytes in the models is indeed observed to promote the emergence of Up-Down regimes with realistic characteristics. Our models show that the difference of signalling timescales between astrocytes and neurons (seconds versus milliseconds) can induce a regime where the frequency of gliotransmission events released by the astrocytes does not synchronize with the Up and Down phases of the neurons, but remains essentially stable. However, these gliotransmission events are found to change the localization of the bifurcations in the parameter space so that with the addition of astrocytes, the network enters a bistability region of the dynamics that corresponds to Up-Down synchronization. Taken together, our work provides a theoretical framework to test scenarios and hypotheses on the modulation of Up-Down dynamics by gliotransmission from astrocytes.