993 resultados para National Savings Fund


Relevância:

80.00% 80.00%

Publicador:

Resumo:

Measurements of the anisotropy parameter v(2) of identified hadrons (pions, kaons, and protons) as a function of centrality, transverse momentum p(T), and transverse kinetic energy KET at midrapidity (vertical bar eta vertical bar < 0.35) in Au + Au collisions at root s(N N) = 200 GeV are presented. Pions and protons are identified up to p(T) = 6 GeV/c, and kaons up to p(T) = 4 GeV/c, by combining information from time-of-flight and aerogel Cerenkov detectors in the PHENIX Experiment. The scaling of v(2) with the number of valence quarks (n(q)) has been studied in different centrality bins as a function of transverse momentum and transverse kinetic energy. A deviation from previously observed quark-number scaling is observed at large values of KET/n(q) in noncentral Au + Au collisions (20-60%), but this scaling remains valid in central collisions (0-10%).

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Volunteering is intricately woven into the fabric of our society. In 2009 alone, approximately 63.4 million Americans participated in volunteer activities, collectively donating over 8.1 billion service-hours (Corporation for National and Community Service [CNCS], 2010). Each service-hour is determined by the U.S. Bureau of Labor Statistics (2010) to be valued at $20.85/hr which translates to a national savings of $169 billion. Thus, we can clearly observe the significance of volunteer contribution to the overall benefit of society. In addition, there is now evidence that voluntary service may also benefit the actual volunteer, especially individuals who are 65+ years. As we reach 2020 this elderly class, composed of nearly 13 million (CNCS, 2010) Americans, will be of much consequence. Their potential to contribute in community-related efforts may save the U.S. billions in labor costs, and may also help reduce healthcare-related expenditures if volunteering proves to be a protective factor. In this literature review, we set out to explore the potential relationship between volunteer participation and increased mental and physical wellness. We also examined volunteer demographic characteristics and common motives for engaging in service-related activities. Analysis showed that volunteer work often combined low-impact physical activity and mental satisfaction from serving others, resulting in overall health benefit. Demographic characteristics displayed were consistent with previous studies and found that a majority of volunteers were female, White, married status, having received college degree or higher, employed, middle-high SES. In addition, age was seen to be a key characteristic in forecasting volunteer motivation and self-reported perceived health benefits.^

Relevância:

80.00% 80.00%

Publicador:

Resumo:

We have analyzed surface-wave propagation that takes place at the boundary between an isotropic medium and a semi-infinite metal-dielectric periodic medium cut normally to the layers. In the range of frequencies where the periodic medium shows hyperbolic space dispersion, hybridization of surface waves (dyakonons) occurs. At low to moderate frequencies, dyakonons enable tighter confinement near the interface in comparison with pure SPPs. On the other hand, a distinct regime governs dispersion of dyakonons at higher frequencies.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

We analyzed surface-wave propagation that takes place at the boundary between a semi-infinite dielectric and a multilayered metamaterial, the latter with indefinite permittivity and cut normally to the layers. Known hyperbolization of the dispersion curve is discussed within distinct spectral regimes, including the role of the surrounding material. Hybridization of surface waves enable tighter confinement near the interface in comparison with pure-TM surface-plasmon polaritons. We demonstrate that the effective-medium approach deviates severely in practical implementations. By using the finite-element method, we predict the existence of long-range oblique surface waves.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

We report on the existence of nondiffracting Bessel surface plasmon polaritons (SPPs), advancing at either superluminal or subluminal phase velocities. These wave fields feature deep subwavelength FWHM, but are supported by high-order homogeneous SPPs of a metal/dielectric (MD) superlattice. The beam axis can be relocated to any MD interface, by interfering multiple converging SPPs with controlled phase matching. Dissipative effects in metals lead to a diffraction-free regime that is limited by the energy attenuation length. However, the ultra-localization of the diffracted wave field might still be maintained by more than one order of magnitude.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

We investigate the existence and dispersion characteristics of surface waves that propagate at an interface between a metal–dielectric superlattice and an isotropic dielectric. Within the long-wavelength limit, when the effective-medium (EM) approximation is valid, the superlattice behaves like a uniaxial plasmonic crystal with the main optical axes perpendicular to the metal–dielectric interfaces. We demonstrate that if such a semi-infinite plasmonic crystal is cut normally to the layer interfaces and brought into contact with a semi-infinite dielectric, a new type of surface mode can appear. Such modes can propagate obliquely to the optical axes if favorable conditions regarding the thickness of the layers and the dielectric permittivities of the constituent materials are met. We show that losses within the metallic layers can be substantially reduced by making the layers sufficiently thin. At the same time, a dramatic enlargement of the range of angles for oblique propagation of the new surface modes is observed. This can lead, however, to field non-locality and consequently to failure of the EM approximation.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

We investigated surface waves guided by the boundary of a semi-infinite layered metal-dielectric nanostructure cut normally to the layers and a semi-infinite dielectric material. Using the Floquet-Bloch formalism, we found that Dyakonov-like surface waves with hybrid polarization can propagate in dramatically enhanced angular range compared to conventional birefringent materials. Our numerical simulations for an Ag-GaAs stack in contact with glass show a low to moderate influence of losses.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

We rigorously analyze the propagation of localized surface waves that takes place at the boundary between a semi-infinite layered metal-dielectric (MD) nanostructure cut normally to the layers and a isotropic medium. It is demonstrated that Dyakonov-like surface waves (also coined dyakonons) with hybrid polarization may propagate in a wide angular range. As a consequence, dyakonon-based wave-packets (DWPs) may feature sub-wavelength beamwidths. Due to the hyperbolic-dispersion regime in plasmonic crystals, supported DWPs are still in the canalization regime. The apparent quadratic beam spreading, however, is driven by dissipation effects in metal.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

The microbiota of multi-pond solar salterns around the world has been analyzed using a variety of culture-dependent and molecular techniques. However, studies addressing the dynamic nature of these systems are very scarce. Here we have characterized the temporal variation during 1 year of the microbiota of five ponds with increasing salinity (from 18% to >40%), by means of CARD-FISH and DGGE. Microbial community structure was statistically correlated with several environmental parameters, including ionic composition and meteorological factors, indicating that the microbial community was dynamic as specific phylotypes appeared only at certain times of the year. In addition to total salinity, microbial composition was strongly influenced by temperature and specific ionic composition. Remarkably, DGGE analyses unveiled the presence of most phylotypes previously detected in hypersaline systems using metagenomics and other molecular techniques, such as the very abundant Haloquadratum and Salinibacter representatives or the recently described low GC Actinobacteria and Nanohaloarchaeota. In addition, an uncultured group of Bacteroidetes was present along the whole range of salinity. Database searches indicated a previously unrecognized widespread distribution of this phylotype. Single-cell genome analysis of five members of this group suggested a set of metabolic characteristics that could provide competitive advantages in hypersaline environments, such as polymer degradation capabilities, the presence of retinal-binding light-activated proton pumps and arsenate reduction potential. In addition, the fairly high metagenomic fragment recruitment obtained for these single cells in both the intermediate and hypersaline ponds further confirm the DGGE data and point to the generalist lifestyle of this new Bacteroidetes group.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Economic conditions which had favoured Russia’s development suddenly changed in mid-2008. The Russian economy was hit, on the one hand, by a drastic slump in oil prices (which fell from nearly US$150 to US$50 between July 2008 and January 2009), and on the other by the outflow of investors (a net of US$130 billion of capital left Russia in the fourth quarter of 2008). Within several months, the financial crisis became an economic crisis affecting the entire economy. The financial reserves accumulated in times of prosperity (more than US$162 billion in the stabilisation funds and nearly US$598 billion in the currency and gold reserve) alleviated the negative impact of the crisis, although this failed to prevent the deep declines in macroeconomic indicators. Russia is one of the states most severely affected by the crisis. In the first half of 2009, its GDP fell by 10.4% compared to the same period in the previous year, while industrial production dropped by nearly 15%, and a decrease in investments of over 18% was reported. The poor economic performance has strongly affected the Russian budget, which reported a deficit for the first time in ten years in 2009. During the first year of the crisis (August 2008 – September 2009), Russia’s financial reserves were seriously reduced as a result of the government’s anti-crisis policy and interventions from the central bank: the reserve fund decreased by nearly 45% to US$76 billion, and the central bank’s reserves shrunk by nearly US$200 billion to US$409 billion. Meanwhile, however, the money in the National Welfare Fund, which had been intended almost entirely to subsidise the Pensions Fund between 2010 and 2015, rose almost three-fold (to US$90 billion). According to government forecasts, the money from the reserve fund is also supposed to be spent fully in 2010. The financial crisis has triggered a dynamic outflow of capital from the Russian market. So-called speculative capital was the first to demonstrate the lack of confidence in the Russian market. In the first half of 2009, the growth rate of long-term investments also decreased noticeably, although no spectacular withdrawal of direct investments from Russia has been observed. The economic crisis has also halted the foreign expansion of Russian private capital, while state-owned capital strengthened its position as an investor. Russia’s raw materials companies continue to be the main category of foreign investors; however, new technologies are gaining prominence as the second main direction of Russian investments.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Casual observation shows that that the financial systems in the southern and eastern Mediterranean are unable (or unwilling) to divert the financial resources that are available to them as funding opportunities to private enterprises. Using a sample of both northern and southern Mediterranean countries for the years 1985 to 2009, this study empirically assesses the reasons underlying such conditions. The results show that strong legal institutions, good democratic governance and adequate implementation of financial reforms can have a substantial positive impact on financial development only when they are present collectively. Moreover, inflation appears to undermine banking development, but less so when the capital account is open. Government debt growth appears to weaken credit growth, which confirms that public debt ‘crowds out’ private debt. Lastly, capital inflows appear to primarily have an income effect, increasing income and thereby national savings, and thus increasing the availability of credit.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Partial support of the Hungarian State Eötvös Scholarship, the Hungarian National Science Fund (Grant No. OTKA 42559 and 42706) and the Mobile Innovation Center, Hungary is gratefully acknowledged.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

This work was supported by the Bulgarian National Science Fund under grant BY-TH-105/2005.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

This work was partially supported by the Bulgarian National Science Fund under Contract No MM 1405. Part of the results were announced at the Fifth International Workshop on Optimal Codes and Related Topics (OCRT), White Lagoon, June 2007, Bulgaria