Narrow Results

Let f be a positive smooth function on a closed Riemann surface (M, g). The f-energy of a map u from M to a Riemannian manifold (N, h) is defined as

The blow-up analysis for a sequence of exponentially harmonic maps from a closed surface is studied to reestablish an existence result of harmonic maps from a closed surface into a closed manifold whose 2-dimensional homotopy class vanishes.

The Split Share Structure Reform in China offers a unique opportunity to test whether the supply of tradable shares (i.e., float) has a significant impact on the degree of speculation. After firms completed the reform, their float increased by 31% on average, while turnover and trading volume also increased substantially. We use information from firms’ reform plan to derive an estimate of the price premium of tradable shares over non-tradable shares before the reform and find that, after controlling for differences in liquidity and profitability, the price premium is significantly related to proxies for the level of speculative trading in tradable shares. Moreover, firms that were highly speculated before the reform had significantly smaller increase in turnover and trading volume than firms that were less speculated. Overall, our evidence confirms that there is a significant speculative component in the market price of tradable shares in China and a large increase in float dampens speculative trading.

The Materia OSCura A Bolle (MOSCAB) experiment uses a new technique for Dark Matter search. The Geyser technique is applied to the construction of a prototype detector with a mass of 0.5 kg and the encouraging results are reported here; an accent is placed on a big detector of 40 kg in construction at the Milano Bicocca University and INFN.

An original approach for accurately measuring the mass transfer of a single bubble rising in a liquid is reported. The approach consists in using PLIF technique (Planar Laser Induced Fluorescence) at micro-scale to capture images of the released oxygen concentration field in the bubble wake. The applicability of the technique for determining mass transfer coefficients in different fluids (1 < Re < 100) is demonstrated and the relevance of the results is corroborated by established correlations. This direct and non-intrusive technique could be a promising tool to enrich the understanding of mass transfer phenomena.

Bubble is the heart of the microfluidic chip, which takes a significant role in drug release, biological detection and so on. In this case, bubble flow characteristics in microfluidic chip are the key to realize its function. In this paper, bubble flow characteristics in the microfluidic chip have been studied with high speed photography system by controlling the wettability and the heat flux of the microelectrode surface. The result shows that bubble flows faster on the electrode with hydrophobic surface. In addition, loading current to the electrode with hydrophilic surface could also speed up the movement of bubble, and the flow rate of bubble increases with the increasing heat flux of the electrode.

A bubble equation of motion close to the solid plane is obtained by using the perturbation method. This bubble equation can explain the phenomena of the reentrant microjet penetrating the bubble produced by the external disturbances if the distance between the bubble center to the solid boundary is small enough as well as the external pressure is large enough. Furthermore, two critical points are found. One critical point is the distance between the bubble center to the solid boundary. The other is external pressure. The critical boundary at which the reentrant microjet can just be produced is given. The critical boundary depends on both the distance between the bubble center to the solid boundary and the ratio of external pressure to the initial pressure of the liquid.

A model for a stock market bubble is based upon the assumption that market agents incorporate trend and deviation of the actual price from the fundamental value into their expectations. Possible price dynamics are analyzed, and necessary conditions for large price deviations are obtained.

Mathematical simulation for cell and division, a complex process resulting from a series of major morphological evolution and biological mechanisms, is shown by using variational principle. Groups of differential equation systems with boundary conditions for the cell walls satisfying come out from analysis on minimally total length. Double bubble model for cell geometric formation is found and a mechanism for tri-bubble model is also investigated here. An interesting fact is that every angle between any two tangent lines at the same intersections of cell edges for both double bubble and tri-bubble is equal to $2\pi /3$. In addition to the derivation of these differential equation models, these theories are also applied to the specific experimental data analysis, and it is found that the model is very consistent with the experimental results.

We consider two models of interacting DNA molecules: First is (four parametric) bubble coalescence model in interacting DNAs (shortly: BCI-DNA). Second is (three parametric) bubble coalescence model in a condensed DNA molecules (shortly BCC-DNA). To study bubble coalescence thermodynamics of BCI-DNA and BCC-DNA models we use methods of statistical physics. Namely, we define Hamiltonian of each model and give their translation-invariant Gibbs measures (TIGMs). For the first model, we find parameters such that corresponding Hamiltonian has up to three TIGMs (three phases of system) biologically meaning existence of three states: “No bubble coalescence”, “Dominated soft zone”, “Bubble coalescence”. For the second model, we show that for any (admissible) parameters, this model has unique TIGM. This is a state where “No bubble coalescence” phase dominates.

The current global financial crisis is the most serious both in terms of magnitude and in terms of scope since the Great Depression. No country has been immune to the economic slowdown. In advanced economies, the financial crisis and the global recession that followed the burst of the global financial bubble have brought severe consequences in terms of employment and output. In developing countries, output contraction, growth slowdown, and rising unemployment have come hand in hand with higher borrowing costs, sluggish export growth, and a significant reduction in international capital flows. As a result, poverty has increased. The global financial crisis has left lasting effects on the structure of financial markets, international capital flows, and the cost of capital for developing countries. The efforts of governments and international financial institutions to buffer the impact of the crisis have been quick and aimed in the right direction. However, many risks remain for the road to recovery. This paper provides a brief explanation of how the current global financial crisis originated, and the underlying factors that turned a relatively small collapse in the subprime mortgage market in the United States into a global crisis. It also explores similarities and differences between the current crisis and past experiences. This comparison can provide a better understanding of the main determinants and transmission mechanisms involved, which can help in the design of a better response to the current situation on the one hand, and in the prevention of future crises or minimizations of their impact on the other. Finally, the paper discusses lessons that can be learned for developing countries, focusing on the policies that governments can implement to mitigate the effects of crises and factors that are important for reducing the risks of experiencing a crisis.

The problem of a rising bubble under acoustic excitation is numerically investigated by means of two boundary element method (BEM) models in this paper. Our approach via BEM is very economical in the requirement of computational resources and yet reasonably accurate. The models have been implemented for the study of a single rising bubble. We now extend our study to introduce acoustic forcing to a bubble whereby the complexity of the problem increases (e.g. inclusion of shape oscillations). We conduct simulations for small to moderate acoustic pressure, driven close to the bubble's resonant frequency and harmonics for a micron-sized bubble for which viscous effects are reported to be of greater significance. Observations are compared with experimental findings with which we attempt to identify and investigate respectively, the associated conditions and mechanisms behind some effects (e.g. influence on rise velocity) on an acoustic bubble.

The literature on the financial crisis is very large and diverse. The intent of this article is to summarize these and other mainstream articles through the lens of two key questions: (1) what caused the crisis? and (2) why have the spillover effects been so devastating in so many industrial countries?

In Section II of this review, we address the demand side for liquidity. Section III presents the supply side of liquidity. Section IV tackles the second question: namely, the contagion effect. Section V introduces the other articles in this special section of the journal.

We study the land and stock markets in Japan circa 1990 and in 2013. While the Nikkei stock average in the late 1980s and its —48% crash in 1990 is generally recognized as a financial market bubble, a bigger bubble and crash was in the land market. The crash in the Nikkei which started on the first trading day of 1990 was predictable in April 1989 using the bond-stock earnings yield model which signalled a crash but not its exact moment. We show that it was possible to use the changepoint detection model based solely on price movements for profitable exits of long positions both circa 1990 and in 2013.

Physical mechanisms of laser cleaning of solid surface from soiling particles and films are discussed. Dry laser cleaning of surface from particles is considered to be a result of inertial force, appearing due to thermal expansion of absorbing particles and/or substrate (shaking-off mechanism). Steam laser cleaning is considered for the cases of absorbing particles and absorbing substrate. In the latter case, peculiarities of bubble formation in the liquid layer under the conditions of ns laser action are analyzed. Laser cleaning of surfaces from films by shaking-off and buckling mechanisms (due to thermal tension) is considered. Conditions of the action of each of them are defined. Other physical mechanisms, blasting and evaporation, are briefly discussed.

Consider a stochastic securities market model with a finite state space and a finite number of trading dates. We study how arbitrage price theory is modified by a no short-selling constraint. The principle of No Arbitrage is characterized by the existence of an equivalent supermartingale measure. If we measure present value as conditional expectations after an equivalent change of measure, then the fundamental value of a security might fall below its market value, leading to the possibility of a price bubble. We show that the Law of One Price holds for marketed claims if and only if there exists an equivalent martingale measure. The latter condition indicates that price bubbles are fragile. Given that the Law of One Price prevails, then a contingent claim has a unique fundamental value if and only if it is the difference of two marketed claims. The main tool for arbitrage analysis in this essay is finite-dimensional LP duality theory.