Anti-competitiveness of Instant Messenger Tying by Microsoft

In this paper, we theoretically analyze Microsoft's tying practice in the instant messenger market. Using a model that highlights distinct features of the instant messenger, which are different from the cases of the web browser and the media player, we show that Microsoft can leverage its monopoly power in the operating system (OS) market to the instant messenger market through tying strategy. Microsoft's messenger tying hurts consumers because it enables Microsoft to monopolize messenger market and so fully exploit consumer's willingness to pay to the OS-messenger bundle. However, since tying saves installing costs, consumer loss is not so serious that total surplus improves under messenger tying. Finally we show that such results are robust to the possibilities of multi-homing in the instant messenger market.Microsoft, instant messenger, tying, foreclosure, multi-homing

Cooper-Pair Spin Current in a Strontium Ruthenate Heterostructure

It has been recognized that the condensation of spin-triplet Cooper pairs requires not only the broken gauge symmetry but also the spin ordering as well. One consequence of this is the possibility of the Cooper-pair spin current analogous to the magnon spin current in magnetic insulators, the analogy also extending to the existence of the Gilbert damping of the collective spin-triplet dynamics. The recently fabricated heterostructure of the thin film of the itinerant ferromagnet SrRuO3 on the bulk Sr2RuO4, the best-known candidate material for the spin-triplet superconductor, offers a promising platform for generating such spin current. We will show how such heterostructure allows us to not only realize the long-range spin valve but also electrically drive the collective spin mode of the spin-triplet order parameter. Our proposal represents both a new realization of the spin superfluidity and a transport signature of the spin-triplet superconductivity.Comment: 5 pages, 3 figure

Anti-Photoagaing and Photo-Protective Compounds from Marine Organisms

This Special Issue Book ""Anti-Photoagaing and Photo-Protective Compounds from Marine Organisms"" is aimed at collecting literature on the below-mentioned keyword topics, which can significantly increase our basic understanding of marine-derived compounds in cosmeceutical product development and increases the value of marine products at the industrial level

Lime pretreatment and enzymatic hydrolysis of corn stover

Renewable energy sources, such as lignocellulosic biomass, are environmentally friendly because they emit less pollution without contributing net carbon dioxide to the atmosphere. Among lignocellulosic biomass, corn stover is a very useful feedstock to economically produce environmentally friendly biofuels. Corn stover was pretreated with an excess of calcium hydroxide (0.5 g Ca(OH)2/g raw biomass) in non-oxidative and oxidative conditions at 25, 35, 45, and 55oC. The optimal condition is 55oC for 4 weeks with aeration, determined by yields of glucan and xylan. The overall yields of glucose (g glucan hydrolyzed/100 g original glucan) and xylose (g xylan hydrolyzed/100 g original xylan) were 91.3 and 51.8 at 15 FPU/g cellulose, respectively. Furthermore, when considering the dissolved fragments of glucan and xylan in the pretreatment liquors, the overall yields of glucose and xylose were 93.2 and 79.5 at 15 FPU/g cellulose, respectively. The pretreatment liquor has no inhibitory effect on ethanol fermentation using Saccharomyces cerevisiae D5A. At the recommended condition, only 0.073 g Ca(OH)2 was consumed per g of raw corn stover. Under extensive delignification conditions, 87.5% of the initial lignin was removed. Extensive delignfication required oxidative treatment and additional lime consumption. Deacetylation quickly reached a plateau within 1 week. Delignification highly depended on temperature and the presence of oxygen. Lignin and hemicellulose were selectively removed, but cellulose was not affected by lime pretreatment in mild temperatures (25 ?? 55oC). The delignification kinetic models of corn stover were empirically determined by three simultaneous first-order reactions. The activation energies for the oxidative delignification were estimated as 50.15 and 54.21 kJ/mol in the bulk and residual phases, respectively. Crystallinity slightly increased with delignification because amorphous components (lignin, hemicellulose) were removed. However, the increased crystallinity did not negatively affect the 3-d sugar yield of enzyme hydrolysis. Oxidative lime pretreatment lowered the acetyl and lignin contents to obtain high digestibility, regardless of crystallinity. The enzymatic digestibility of lime-treated biomass was affected by the change of structural features (acetylation, lignification, and crystallization) resulting from the treatment. The non-linear models for 3-d hydrolysis yields of glucan and xylan were empirically established as a function of the residual lignin fraction for the corn stover pretreated with lime and air

Relationships among Perceived Working Hours, General Stress, Work Centrality, Job Control, Job Demands, and Work Condition Constraints

Although working hours are generally regarded as a major indicator of stress, little exploration has been done about how working hours influence stress with the relevant individual and job characteristics. The purpose of this study was to examine the relationships among perceived working hours, general stress, work centrality, job control, job demands, and work condition constraints for full-time employees in the United States and Korea. A self-administered questionnaire survey approach was used to collect data which were utilized to reflect six variables of this study. The sample size was 805 (U.S.: 397, Korea: 408). As the results from the measurement invariance test indicated that the measurement model was not invariant by country, statistical examinations were conducted separately for each country to test hypotheses. In the path analysis, for the U.S. sample, Job Demands was significantly associated with Perceived Working Hours. Job Demands and Work Condition Constraints were significantly related to General Stress. There was a significant relationship between Work Condition Constraints and Job Demands. There were significant mediation effects for the relationships between Work Condition Constraints and Perceived Working Hours via Job Demands and between Work Condition Constraints and General Stress via Job Demands. For the Korean sample, in the path analysis, Work Centrality and Job Demands were significantly associated with Perceived Working Hours. Job Demands, Job Control, and Work Condition Constraints were significantly associated with General Stress. There was a significant relationship between Work Condition Constraints and Job Demands. All the hypothesized mediation effects were significant: from Job Demands via Perceived Working Hours to General Stress, from Work Condition Constraints via Job Demands to Perceived Working Hours, and Work Condition Constraints via Job Demands to General Stress. It was found that this study overall supported the selected theories and related research. The significance of this study includes contributions to work-life/work-family balance studies that are an emerging research area in HRD, practical implications for sound work-settings, and cultural validations of the theories related to working hours and stress. Limitations, implications for theories, research, and practices were also discussed

The Sylvester Theorem and the Rogers-Ramanujan Identities over Totally Real Number Fields

In this paper, we prove two identities on the partition of a totally positive algebraic integer over a totally real number field which are the generalization of the Sylvester Theorem and that of the Rogers-Ramanujan Identities. Additionally, we give an another version of generalized Rogers-Ramanujan Identities

The Euler-Glaisher Theorem over Totally Real Number Fields

In this paper, we study the partition theory over totally real number fields. Let $K$ be a totally real number field. A partition of a totally positive algebraic integer $\delta$ over $K$ is $\lambda=(\lambda_1,\lambda_2,\ldots,\lambda_r)$ for some totally positive integers $\lambda_i$ such that $\delta=\lambda_1+\lambda_2+\cdots+\lambda_r$. We find an identity to explain the number of partitions of $\delta$ whose parts do not belong to a given ideal $\mathfrak a$. We obtain a generalization of the Euler-Glaisher Theorem over totally real number fields as a corollary. We also prove that the number of solutions to the equation $\delta=x_1+2x_2+\cdots+nx_n$ with $x_i$ totally positive or $0$ is equal to that of chain partitions of $\delta$. A chain partition of $\delta$ is a partition $\lambda=(\lambda_1,\lambda_2,\ldots,\lambda_r)$ of $\delta$ such that $\lambda_{i+1}-\lambda_i$ is totally positive or $0$

Fundamental Elements for Successful Performance of CT Colonography (Virtual Colonoscopy)

There are many factors affecting the successful performance of CT colonography (CTC). Adequate colonic cleansing and distention, the optimal CT technique and interpretation with using the newest CTC software by a trained reader will help ensure high accuracy for lesion detection. Fecal and fluid tagging may improve the diagnostic accuracy and allow for reduced bowel preparation. Automated carbon dioxide insufflation is more efficient and may be safer for colonic distention as compared to manual room air insufflation. CT scanning should use thin collimation of ≤3 mm with a reconstruction interval of ≤1.5 mm and a low radiation dose. There is not any one correct method for the interpretation of CTC; therefore, readers should be well-versed with both the primary 3D and 2D reviews. Polyps detected at CTC should be measured accurately and reported following the "polyp size-based" patient management system. The time-intensive nature of CTC and the limited resources for training radiologists appear to be the major barriers for implementing CTC in Korea