Explore the vast range of titles available.

Using historical data on postwar financial crises around the world, we show that the combination of rapid credit and asset price growth over the prior three years, whether in the nonfinancial business or the household sector, is associated with a 40% probability of entering a financial crisis within the next three years. This compares with a roughly 7% probability in normal times, when neither credit nor asset price growth is elevated. Our evidence challenges the view that financial crises are unpredictable \"bolts from the sky\" and supports the Kindleberger-Minsky view that crises are the byproduct of predictable, boom-bust credit cycles. This predictability favors policies that lean against incipient credit-market booms.

The temporal relationship between global glaciations and the Great Oxidation Event (GOE) suggests that climate change played an important role in Earth's oxygenation. The potential role of temperature is captured by the stratigraphic proximity between glacial deposits and sediments containing mass‐independent fractionation of sulfur isotopes (MIF‐S). We use a time‐dependent one‐dimensional photochemical model to investigate whether temperature changes associated with global glaciations can drive oscillations in atmospheric O2 levels and MIF‐S production across the GOE. We find that extreme climate change can cause atmospheric O2 to oscillate between pre (<10−6 times the present atmospheric level, PAL) and post‐GOE (>10−5 PAL) levels. Post‐glacial hot‐moist greenhouse climates lead to post‐GOE O2 levels because the abundant H2O vapor and oxidizing radicals drive the depletion of reduced species. This pattern is generally consistent with the MIF‐S signal observed in the sedimentary record, suggesting a link between global glaciations and O2 oscillations across the GOE. Plain Language Summary The Great Oxidation Event was the most significant environmental and chemical transformation in Earth's history, marking the first time oxygen accumulated in the atmosphere around 2.4 billion years ago. Oxygen increased from below one millionth (low) to at least one‐thousandth of a percent (intermediate) of the present oxygen concentration during this event. However, measurements of geochemical oxygen proxies suggest that oxygen levels oscillated between low and intermediate levels before stabilizing after this event. The first rise of atmospheric oxygen occurred during a period of extreme climate variability indicated by the presence of glacial rock deposits around this time. In this study, we use a time‐dependent photochemical model to show that extreme temperature changes caused by global glaciations can drive oscillations in atmospheric oxygen levels across the Great Oxidation Event (GOE). Our results can help explain why atmospheric oxygen shows drastic changes across the GOE in a way that is consistent with the geochemical record. Key Points Across the Great Oxidation Event (GOE), extreme climate change linked to global glaciations can drive oscillations in atmospheric O2 levels and mass‐independent fractionation of sulfur isotopes (MIF‐S) production Glacial climates and hot‐moist greenhouse climates were likely characterized by pre‐GOE and post‐GOE O2 levels respectively Temperature changes associated with global glaciations can help explain the MIF‐S record across the GOE

We study the boundary behavior of solutions to the Dirichlet problems for integro-differential operators with order of differentiability s ∈ ( 0 , 1 ) and summability p > 1 . We establish a nonlocal counterpart of the Wiener criterion, which characterizes a regular boundary point in terms of the nonlocal nonlinear potential theory.

The paper outlines the divergence of beam and operating wavelength bands effects on free-space optics communication channels in local access networks. The max Q factor and min bit error rate are measured based on the divergence of beam and operating wavelength bands variations. The signal is tested also at the receiver side by using an optical power meter visualizer at various operating signal wavelength bands and under the optimum values of the divergence of the beam. The study has presented the optimum operating conditions for upgrading network operation efficiency.

We describe the development of Chempath, an open-source pathway analysis program for photochemical models. This algorithm can help understand the results of complex photochemical models by identifying the most important reaction chains (pathways) for the production and destruction of a species of interest in a reaction system. The algorithm can also quantify the contributions of the pathways to the production and destruction of a species. Chempath is an open-source Python re-implementation of the algorithm developed by . However, Chempath does not include the balance of concentration changes and reaction rates that Lehmann's algorithm uses to eliminate imbalances due to numerical errors. Instead, Chempath quantifies the contributions of these imbalances to the production and destruction of a species.We demonstrate how to apply Chempath to both a simple box model and a one-dimensional photochemical model, using a reaction system for Earth's present-day atmosphere. Chempath can identify well-known chemical mechanisms for O3 production and destruction in these models, suggesting that this algorithm can be applied to understand photochemical models of less-well-known atmospheres, like past and exoplanet atmospheres.

Carbonate mud represents one of the most important geochemical archives for reconstructing ancient climatic, environmental, and evolutionary change from the rock record. Mud also represents a major sink in the global carbon cycle. Yet, there remains no consensus about how and where carbonate mud is formed. Here, we present stable isotope and trace-element data from carbonate constituents in the Bahamas, including ooids, corals, foraminifera, and algae. We use geochemical fingerprinting to demonstrate that carbonate mud cannot be sourced from the abrasion and mixture of any combination of these macroscopic grains. Instead, an inverse Bayesian mixing model requires the presence of an additional aragonite source.We posit that this source represents a direct seawater precipitate. We use geological and geochemical data to show that “whitings” are unlikely to be the dominant source of this precipitate and, instead, present a model for mud precipitation on the bank margins that can explain the geographical distribution, clumped-isotope thermometry, and stable isotope signature of carbonate mud. Next, we address the enigma of why mud and ooids are so abundant in the Bahamas, yet so rare in the rest of the world: Mediterranean outflow feeds the Bahamas with the most alkaline waters in themodern ocean (>99.7th-percentile). Such high alkalinity appears to be a prerequisite for the nonskeletal carbonate factory because, when Mediterranean outflow was reduced in the Miocene, Bahamian carbonate export ceased for 3-million-years. Finally, we show how shutting off and turning on the shallow carbonate factory can send ripples through the global climate system.

Objectives: This study explored the relationship between physical activity, generalized anxiety disorder, and suicidal risk among South Korean adolescents, considering individual characteristics. Methods: The study analyzed raw data from the 2023 Youth Health Behavior Survey conducted by the Korea Disease Control and Prevention Agency. A total of 52,880 adolescents’ data (weighted to 2,581,964) were analyzed using a complex sample design. Results: Physical activity level had a negative effect on anxiety. Anxiety had a positive effect on suicidal risk, including thoughts, plans, and attempts. Physical activity level indirectly affected suicidal risk negatively by mediating anxiety. Individual characteristics such as gender, alcohol consumption, smoking, drug use, and household economic status also influenced suicidal risk. Conclusions: This study emphasizes that effectively reducing adolescent suicide rates requires a multifaceted approach. Such an approach should include promoting physical activity, addressing mental health challenges like anxiety, and providing tailored support for vulnerable populations.

The thermal conductivity enhancement of neat poly(vinyl alcohol) and poly(vinyl alcohol) (PVA)/cellulose nanocrystal (CNC) composite was attempted via electrospinning. The suspended microdevice technique was applied to measure the thermal conductivity of electrospun nanofibers (NFs). Neat PVA NFs and PVA/CNC NFs with a diameter of approximately 200 nm showed thermal conductivities of 1.23 and 0.74 W/m-K, respectively, at room temperature, which are higher than that of bulk PVA by factors of 6 and 3.5, respectively. Material characterization by Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis confirmed that the thermal conductivity of the PVA/CNC NFs was enhanced by the reinforcement of their backbone rigidity, while that of the neat PVA NFs was attributed to the increase in their crystallinity that occurred during the electrospinning.

In this paper, we study generalized Schauder theory for the degenerate/singular parabolic equations of the form u t = a i ′ j ′ u i ′ j ′ + 2 x n γ / 2 a i ′ n u i ′ n + x n γ a nn u nn + b i ′ u i ′ + x n γ / 2 b n u n + c u + f ( γ ≤ 1 ) . When the equation above is singular, it can be derived from Monge–Ampère equations by using the partial Legendre transform. Also, we study the fractional version of Taylor expansion for the solution u , which is called s -polynomial. To prove C s 2 + α -regularity and higher regularity of the solution u , we establish generalized Schauder theory which approximates coefficients of the operator with s -polynomials rather than constants. The generalized Schauder theory not only recovers the proof for uniformly parabolic equations but is also applicable to other operators that are difficult to apply the bootstrap argument to obtain higher regularity.

Abstract not available J Bangladesh Coll Phys Surg 2023; 41: 100-101