Bubble Burst Research Articles

Quantitative Easing’s Effects on the U.S. Housing Market

As the housing bubble burst in the United States, the buildup of subprime lending led to the Global Financial Crisis. The Federal Reserve desperately slashes interest rates to reverse the economic recession, but the Zero Lower Bound significantly hindered the policy's future effectiveness with concerns of an existing liquidity trap. As a result, the unprecedented Quantitative Easing became the policymakers' last resort. Through the large-scale purchases of financial assets including mortgage-backed securities (MBS) and government bonds, the Fed attempts to stimulate the economy through reserve creation and instilling downward pressure on future interest rates. This literature review discusses how QE specifically affected the U.S. housing market during the GFC. An analysis is conducted on various social aspects and stakeholders by identifying the various channels through which QE is transmitted. The signaling, bank lending, and refinancing channels all suggest that MBS had the greatest effect on market expectations, bank behaviors, and consumer spending. As a result, many were many spillover effects into real estate, notably on asset prices, employment, and investment. Even though literature has criticized QE's ineffectiveness and its potential drawbacks, the unconventional monetary policy certainly played an essential role in preventing a worse outcome and effectively demonstrating its ability to reduce interest rates, generate wealth, and revive the economy.

Water–air transfer rates of microplastic particles through bubble bursting as a function of particle size

Microplastic (MP) particles can be ejected into the air by jet drops when gas bubbles burst at water surfaces. For a qualitative and quantitative understanding of this transport mechanism from the hydrosphere to the atmosphere, we studied the transfer of MP due to bubble bursting at the air–water interface in laboratory experiments. Gas bubbles were produced with filtered air that was pushed through a stainless-steel frit at two different volume flow rates in a glass flask filled with polystyrene (PS) particles of six different diameters (0.35 µm, 0.5 µm, 0.75 µm, 1 µm, 1.5 µm, 2 µm) suspended in deionized water. Airborne PS particle concentrations were measured by an optical particle counter. Additionally, size and volume of the bursting bubbles and the resulting jet droplets were analyzed with a camera. Depending on the volume flow rates, bubble bursting rates from 688 s−1 to 1176 s−1 and mean diameters of the bursting bubbles from 0.76 mm to 0.81 mm were observed. The mean diameters of the top jet drops were estimated to be between 0.10 mm and 0.11 mm. The measured number of jet droplets ranged from 2092 s−1 to 2391 s−1. For particle diameters from 0.35 µm – 2.0 µm, the airborne MP particle concentrations ranged from 4.2 l−1 to 348 l−1. We determined size-dependent transfer factors for the water–air transfer and found a maximum for 1 µm particles. For MP particles up to 1 µm diameter, the particle concentration in the jet droplets was enhanced compared to the bulk water concentration, indicating an enrichment of MP particles at the water–air-interface of bubbles.

An Experimental Database for the Analysis of Bursting of a Laminar Separation Bubble

The bursting phenomenon consists in the switch of a laminar separation bubble from a short to a long configuration. In the former case, reduced effects on profile pressure distribution are typically observed with respect to the attached condition. On the contrary, long bubbles provoke significant variations in the loading coefficient upstream of the separation position, with increased risk of stall of the lifting surfaces. The present work presents an experimental database describing separated boundary layers evolving under different Reynolds numbers, adverse pressure gradients and free-stream turbulence levels. Overall, more than 80 flow conditions were tested concerning short and long bubbles for the characterization of separated flows under turbine-like conditions. Measurements were performed on a flat plate geometry using a fast-response Particle Image Velocimetry (PIV) system. For each flow case, two sets of 6000 flow records were acquired with an acquisition frequency equal to 300 and 1000 Hz. Based on existing criteria for the identification of the bursting phenomenon, the flow cases were clustered in terms of short and long bubble states. Additionally, the kind of instability (i.e., convective or absolute) developing into the separated boundary layer was identified based on flow statistics. The present data captures the existing link between the bursting of a laminar separation bubble and the onset of the absolute instability of the separated shear layer, with stationary vortices forming in the dead air region.

Lessons from a Bubble Burst

Lessons from a Bubble Burst

Air bag-embedded MIL-101(Fe) metal-organic frameworks for an amplified tumor microenvironment activation loop through strategic delivery of iron ions and lentinan.

Background: Iron-based nanocarriers have demonstrated potential in redirecting tumor associated macrophages (TAMs) polarization towards the M1 phenotype, critical for activating the tumor microenvironment (TME) in triple negative breast cancer (TNBC). However, their real-world effectiveness is curtailed by insufficient Fe2+/3+ exposure and the absence of suitable synergists in tumors. Methods: We introduce an air bag-embedded iron-based MIL-101 metal-organic frameworks (MOFMIL-101(Fe)) for igniting the TME in TNBC through bubble-driven tumoral codelivery of Fe2+/3+ and lentinan. This system, named HM/Ef/LNT-MOFMIL-101(Fe), features nano-sized MOFMIL-101(Fe) as the core, embedded NaHCO3 as a pH-triggered air bag, electrostatically-adsorbed lentinan forming the inner shell, and a shield shell with 4T1&red blood cell hybrid membrane. Results: HM/Ef/LNT-MOFMIL-101(Fe) can mitigate non-specific capture in the bloodstream but respond to the acidic tumor milieu, rapidly generating a burst of CO2 bubbles to disassemble MOFMIL-101(Fe). Upon entering tumors, lentinan-induced interferon-γ (IFN-γ) enable Fe2+/3+ facilitating an enhanced ferroptosis and Fenton-like reaction, pushing TAMs towards M1 polarization via the "IFN-γ-ferroptosis-ROS-Caspase-3" pathway. Moreover, HM/Ef/LNT-MOFMIL-101(Fe) increases the infiltration of T lymphocytes and decreases regulatory T cells. These cascading immune responses synergistically foster a loop of amplified TME activation based on TAMs M1 polarization, showcasing notable advancements in anticancer effectiveness and promise for various combination therapies. Conclusion: This study utilizes an "embedded air-bag" strategy to achieve strategic codelivery of Fe2+/3+ and lentinan, providing a new tool for engineering the TME.

The measurement of financial support for real estate and house price bubbles and their dynamic relationship: An empirical study based on 31 major cities in China

<p>In recent years, China's real estate prices have continued to rise, preventing the bursting of the house price bubble, and the various risks it triggers has become an important issue that governments at all levels have to face. In this paper, the backward sup ADF (BSADF) method was used to dynamically portray the evolution of real estate price bubbles in 31 large and medium-sized cities in China over a period of 11 years, from 2013 to 2021, and the dynamic relationship between the degree of financial support for real estate (hereinafter referred to as financial support) and house price bubbles in cities was investigated by employing a panel vector autoregressive (PVAR) model with panel data. The results showed that: Multiple cyclical bubbles significantly existed in the real estate markets of the cities during the study period, and in general, house price bubbles appeared earlier in the more economically developed regions than in the less economically developed regions and have spread to the less economically developed regions. Financial support contributed to house price bubbles, supporting the theory of excessive financial support. Furthermore, the results of the sub-sample showed that financial support contributed most strongly to house price bubbles in cities in the northern region.</p>

Corporate Governance Practices: A Global Perspective with a Focus on Ghana

Following the burst of the high-tech bubble and corporate finance scandals, corporate governance (CG) has emerged as a critical global concern. This study explores corporate practices on a global scale, with particular attention to the International Corporate Governance Standards. It seeks to comprehend how organizations prioritize CG practices, especially from the Ghanaian perspective.The study employed both secondary and primary data to investigate the research. Relying on secondary data, the researcher reviewed relevant textbooks, journals, web-based sources, official company documents, published reports, newspapers, articles and monographs. The researcher also gathered primary data by administering questionnaire to respondents. Out of 99 respondents to whom questionnaires were sent, 78 (representing 79%) returned their responses. Upon receipt, the researcher used SPSS 15.0 to draw bar chart in order to analyse the results. The findings indicate that while Ghana has made significant strides in promoting CG awareness and implementing robust policies supported by laws and institutions, there remain gaps between stated priorities and actual practices. Issues such as conflicts of interest, lack of effective oversight by audit committees, and discrepancies in disclosure practices suggest areas for improvement.

Research on the Formation Mechanism, Contagion Effect and Regulatory Strategy of Digital Asset Price Bubble Risk in the Information Age

Abstract As an emerging financial instrument, the risk of asset price bubbles is becoming more and more prominent and has a far-reaching impact on the global financial market. Based on the ADF model and PSY algorithm, the study constructs an asset price bubble identification model, explores the formation mechanism of asset price bubbles in the financial market, the contagion effect of asset price bubbles in the inter-market, and ultimately puts forward suggestions for targeted regulatory strategies. In the numerical simulation of the formation mechanism of asset price bubbles, both Bubble 1 and Bubble 2 experience 10 periods, and the peaks of the two bubbles appear at t=14 and t=34.5, respectively. The rate of rise of asset prices is slower than the rate of decline, and the impact on the financial market is greater when the financial asset bubble bursts. There is a two-way bidirectional contagion effect between the three markets of stock, bond, and property. Therefore, regulation of asset price bubbles should focus on improving the stock market trading system, publicizing and educating, and restricting real estate loans.

Special report: has the online pharmacy bubble burst?

Special report: has the online pharmacy bubble burst?

Experimental study on the film droplet production from a bubble burst on the free surface

The aerosol released during a severe reactor accident may be retained in the liquid pool. During the venting stage of the suppression pool, bubbles generated in the pool will rise to the free surface and burst to generate droplets. The airflow re-entrains aerosols from the liquid to the air via droplets. Accurate evaluation of droplet entrainment needs to acquire the diameter and number of droplets generated by a bubble, so studying the various behaviors that affect the above parameters is necessary. In this paper, high-speed photography is used to visualize the phenomenon of a single bubble burst to generate film droplets in deionized water and TiO2 suspensions at different phase temperatures. Image processing is used to obtain the bubble film opening rate, the bubble burst position, the bubble lifetime, and the diameter and number of film droplets. The results show that the film thickness decays with time in a power law with a parameter of 2/3, and the newly defined film thickness also decays with time in a power law after considering the bubble radius and physical parameters. This rule is applicable in different liquid temperatures and solutes. Besides, the film thickness increases with liquid temperature and aerosol concentration; the bubble lifetime obeys the Weibull distribution, with the average bubble lifetime of deionized water varies non-monotonically with the liquid temperature, the average lifetime increase with aerosol concentration and liquid temperature in aerosol suspension; The average droplet diameter decreases with bubble lifetime in a power law with a parameter of 5/16, the droplet diameter distribution can be calculated by the gamma distribution of the normalized droplet diameter and the bubble lifetime, and in good agreement with the experimental data, the droplet entrainment factor can also be calculated from the critical droplet diameter and bubble lifetime, which decreases with bubble lifetime.

A micro-foundation of a simple financial model with finite-time singularity bubble and its agent-based simulation

This paper proposes a mathematical model of financial security prices in continuous time with bubbles in which prices may diverge and crash in finite time. Just before the bubbles burst, prices increase super-exponentially. In addition, a discrete-time excess demand model is proposed to provide a micro-foundation for the continuous-time model. The derived discrete-time security price model has the same characteristics as the continuous-time price model and expresses the finite-time singularity. Furthermore, based on the excess demand model, an agent-based simulation is performed to check the price behavior. As expected, we can confirm that prices can diverge in finite time and increase super-exponentially.

Is atmospheric pathway a significant contributor to microplastics in the marine environment?

Transmission of microplastics (MPs) through aerosolization has been recently realized as an important route. Inspite of the reports of the ubiquitous MP presence in aerosols, the spatio-temporal information is inadequate and has very limited practicality in assessing if aerosol can be a significant source of MPs to the marine environment. Data on marine contribution to atmospheric MPs is exceptionally scarce, and the ocean-air exchange is considered an emerging research area. Evidence of MPs entering the oceans via atmospheric deposition has been recently produced. The idea of ocean-air exchange emanates from the fact that beach sediments can get suspended under sand and dust storms, bubble bursts and sea sprays due to wind and waves in surf zones can lead to the ejection of particles into aerosols. In this succinct review, we have tried compiling the data on atmospheric MPs that can shed some light on the flux from and to the aquatic environment. While the information is too limited never the less its incorporation into the marine MP cycle cannot be neglected.

AIR BUBBLE ENCAPSULATION OF EUKARYOTIC CELLS AND THERAPY FAILURES

Background: The purpose of this manuscript is to introduce a newly discovered potential dangers of air bubbles used for therapeutic or diagnostic purposes into the human body.At present, the injection of air bubbles into the human body for diagnostic purpose is viewed positively by the medical/scientific community. In Vitro experiments are presented whereby cells isolation by air bubbles could interfere with chemotherapy treatments.Methods: Author’s own saliva sample was spitted out onto the center of a clean 25X75x1mm glass slide. The sample was placed and focused on the viewing platform of a video microscope. A toothpick was used to harvest inner cheek cells and gently transfer onto the spitted out sample. After focusing, areas were selected showing floating cells and air bubbles. Different laminar levels were observed by cells migrating at different levels.While microscopically observing the sample, the glass slide was disturbed by finger tapping, the aim to induce bubble bursting.Results: Deformed cells were observed when adhering to the outer surface of air bubbles. Additionally, undeformed cells seen at two distinct perpendicular layers when trapped within the floating bubbles. Noticed was a selective attraction of cells by the outer edge of the floating bubbles. Cells attached to the bubble’s edge were being deformed and attracted to each other. Cells were also observed passing unattracted when in a separate laminar flow under the floating bubble. The provocative tapping causing air bubbles to cavitate and burst.Conclusions: The bursting of an air bubble is not the only factor in floating eukaryotic cells deformation. In this manuscript video microscopy and still images are introduced demonstrating a newly found horizontal flat parallel energy field in the periphery of the oxygen bubble. This energy is evident in the free-floating air bubble interface as cheek eukaryotic cells adhere only to the flat round edge of a bubble. Cells are attracted, adhered to each other, and deformed by their own intrinsic attraction. Once the bubble bursts, cells and debris are dispersed, with cells adherence partially disturbed. Cell deformations persisting. It could be hypothesized that cancer cells trapped at different laminar layers inside the bubble be refractory to external chemotherapy agents thus retaining their cancer characteristics.

The Influence That Jeonse Rental System Brought to the Housing Bubble in Korea

The bubble burst, and the South Korean property market plummeted. Thousands of Koreans should not be able to afford their debts and choose to commit suicide. Prior to this, South Koreas real estate market soared rapidly, and no one noticed the abnormality and the future direction of the real estate market. That was a miracle, but it only lasted for a while, and one of the most important factors that accelerated its destruction was a rental system called Jeonse. The purpose of this paper is to explore the impact of Jeonse, a unique rental system, on the Korean real estate market. Housing prices in South Korea have soared amidst the global pandemic. By studying macroeconomics, the global capital chain, and policy-related factors that affect the market, it seems necessary for the government to understand the importance of controlling leverage and properly using quantitative easing. Those methods can theoretically prevent the economic crisis, slow down the creation of bubbles, or decrease the influence made by the contagions it creates.

Pseudo-vagal Responses Elicited by Cryoballoon Ablation.

Pulmonary vein isolation via cryoballoon (CB) ablation is the cornerstone ablation strategy for the treatment of atrial fibrillation (AF). Acute intraprocedural hypotensive and/or bradycardic responses have been reported in patients undergoing CB ablation for AF. However, it remains unclear as to whether these are due to a true vagal response (VR), which can be used to predict long-term outcomes of CB ablation. We analyzed 139 freezes across 17 patients who received CB ablation for paroxysmal AF, measuring vital signs and freeze characteristics. Only one freeze was associated with both hypotension and bradycardia, constituting a true VR. Several freezes were associated with hypotension only that did not respond to atropine administration, suggesting that these responses are not associated with a VR. Hypotensive responses were significantly associated with ice bubble bursts during CB deflation. Unlike the true VR reported in patients undergoing conscious sedation, the presence of acute hypotension shortly after CB deflation cannot be used as a predictor for long-term ablation outcomes.

Dynamic stall characteristics of unswept pitching wing

An experimental investigation of dynamic stall on upswept pitching wing was conducted using Particle Image Velocimetry (PIV) and Pressure Sensitive Paint (PSP) techniques. The wing had an aspect ratio AR = 4 and a NACA 0012 airfoil section profile assembled with a round-tip. The wing motion of interest in this study is pitching at a certain angle of attack range and the wing was robustly designed and machined out of Aluminum to minimize elasticity and tip flapping motions. The freestream Mach number, M∞ = 0.1, and the Reynolds number based on chord length, Rec = 2 × 105, were considered as flow parameters for observing dynamic stall phenomena and for comparison with available numerical simulations from literature. The pitching motion of the wing is sinusoidal with a reduced frequency k = πfc/U∞ = 0.1, and the minimum and maximum angle of attack of the pitching motion were 4° and 22°, respectively. Details of flow structures during pitching at various phase angles were captured using planar two-dimensional (2D) PIV at three spans, x/c = 0.5, 0.75, and 1.0 and the pressure imprint on the surface of the wing was captured by a single shot lifetime method using fast porous pressure-sensitive paint. The initial results show the formation of a separation bubble at a small incident angle and the emergence of a dynamic stall vortex (DSV) after the bursting of the separation bubble. The DSV propagates towards the trailing edge of the wing with its integral scale varying across the three spans of the wing revealing three-dimensionality. The PSP results show a uniform build of suction pressure at low angle of attack which later intensifies in a non-uniform manner due to a circulatory motion of the flow during pitching. After the end of the upstroke phase, the flow starts to reattach to the surface of the wing while the DSV grows and moves away from the surface as it travels downstream along the chord until sheds beyond the trailing edge. The PSP results also capture the tip unloading period during the pitching motion.

ANALYSIS OF EMOTIONAL EXHAUSTION THROUGH DOWNSIZING WITH JOB SATISFACTION AS MEDIATION

Nowadays, many tech companies are on a downward trend. This can be referred to as a tech bubble burst. This makes it very difficult for companies, especially those in the e-commerce industry, financially. These companies are constantly looking for ways to make efficiencies in order to save costs and streamline the company. There are many ways to do that, but the most commonly used is downsizing. Downsizing is a way of efficiency by removing unnecessary employees to avoid unnecessary costs. Although downsizing is effective in saving costs, there are some negative effects of downsizing, namely its effect on emotional exhaustion and job satisfaction of the remaining employees in the company or can be said to be layoff survivors. Emotional exhaustion can be interpreted as emotional exhaustion towards their work while job satisfaction is the feeling of satisfaction that a person has when doing their job. The purpose of this study is to determine and analyze the effect of downsizing on emotional exhaustion and job satisfaction of employees working in the e-commerce industry in Indonesia. This study uses quantitative research methods with a cross sectional approach and non-probability sampling techniques with data obtained by means of questionnaires distributed to 180 respondents. The results of this study Downsizing has a significant effect on emotional exhaustion, Downsizing has a significant effect on job satisfaction, Job Satisfaction has a significant effect on emotional exhaustion, Job Satisfaction can mediate the effect of downsizing on emotional exhaustion.

Predicting stock market crashes on the African stock markets: evidence from log-periodic power law model

PurposeThis study aims to predict stock market crashes identified by the CMAX approach (current index level relative to historical maximum) during periods of global and local events, namely the subprime crisis of 2008, the political and social instability of 2011 and the COVID-19 pandemic.Design/methodology/approachOver the period 2004–2020, a log-periodic power law model (LPPL) has been employed which describes the price dynamics preceding the beginning dates of the crisis. In order to adjust the LPPL model, the Global Search algorithm was developed using the “fmincon” function.FindingsBy minimizing the sum of square errors between the observed logarithmic indices and the LPPL predicted values, the authors find that the estimated parameters satisfy all the constraints imposed in the literature. Moreover, the adjustment line of the LPPL models to the logarithms of the indices closely corresponds to the observed trend of the logarithms of the indices, which was overall bullish before the crashes. The most predicted dates correspond to the start dates of the stock market crashes identified by the CMAX approach. Therefore, the forecasted stock market crashes are the results of the bursting of speculative bubbles and, consequently, of the price deviation from their fundamental values.Practical implicationsThe adoption of the LPPL model might be very beneficial for financial market participants in reducing their financial crash risk exposure and managing their equity portfolio risk.Originality/valueThis study differs from previous research in several ways. First of all, to the best of the authors' knowledge, the authors' paper is among the first to show stock market crises detection and prediction, specifically in African countries, since they generate recessionary economic and social dynamics on a large extent and on multiple regional and global scales. Second, in this manuscript, the authors employ the LPPL model, which can expect the most probable day of the beginning of the crash by analyzing excessive stock price volatility.

Application of the LPPL model in the identification and measurement of structural bubbles in the Chinese stock market

This study proposes innovative methods for determining the starting point and estimating the parameters of the LPPL model for predicting stock market bubbles. These methods address the challenges in determining the starting point of irregularly staged bubbles and the issues of multiple local optima or no solutions in previous prediction algorithms. The proposed LPPL model, incorporating innovative algorithms, is applied to the Chinese A-share market from 2018 to 2021. The starting points of structural bubbles are determined using the difference and grid search methods, and the sequential quadratic programming (SQP) algorithm is used to estimate the parameters of the LPPL model. The study measures and warns about structural bubbles in the A-share market. The results demonstrate that the LPPL model with the innovative algorithm can accurately measure staged and structural bubbles in the A-share market and provide reasonably accurate warnings of bubble bursts, which have been confirmed by the market multiple times.

A Macroprudential Analysis of the 2008 Financial Crisis

The subprime crisis of the late 2000s had a profound impact on the global financial system, triggering an economic downturn of unprecedented magnitude. This paper provides a comprehensive analysis of the causes, consequences, and lessons learned from the subprime crisis. The crisis emerged from a combination of factors, including the expansion of subprime mortgage lending, relaxed underwriting standards, and the bursting of the housing bubble. Financial institutions eagerly pursued higher profits by issuing mortgage loans to borrowers with questionable creditworthiness, leading to a surge in loan defaults and foreclosures when the housing market collapsed. The consequences of the crisis were far-reaching. It resulted in widespread financial turmoil, with significant losses incurred by interconnected institutions worldwide. The global economy experienced a severe recession, characterized by high unemployment, declining consumer and investor confidence, and disruptions across various industries. The subprime crisis highlighted critical weaknesses in risk management practices, regulatory oversight, and financial market mechanisms. However, it also served as a catalyst for reform. Policymakers implemented measures to strengthen financial systems, enhance transparency, and improve risk assessment and management. Revisions to regulatory frameworks, stricter stress testing, and reinforced consumer protection measures were among the responses.