Axion Dark Matter and Cosmological Parameters

We observe that photon cooling after big bang nucleosynthesis (BBN) but before recombination can remove the conflict between the observed and theoretically predicted value of the primordial abundance of $^7$Li. Such cooling is ordinarily difficult to achieve. However, the recent realization that dark matter axions form a Bose-Einstein condensate (BEC) provides a possible mechanism, because the much colder axions may reach thermal contact with the photons. This proposal predicts a high effective number of neutrinos as measured by the cosmic microwave anisotropy spectrum.Comment: 4 pages, one figure. Version to appear in Phys. Rev. Lett., incorporating useful comments by the referees and emphasizing that photon cooling by axion BEC is a possibility, not a certaint

Settlement in Sands Due to Cyclic Loading

Stress controlled undrained cyclic triaxial tests have been conducted on undisturbed sandy and silty soil samples obtained by special sampler in order to minimize the effect of disturbance. The influence of fines content on liquefaction - induced volumetric strains have been studied. The results indicate that cyclic mobility of sands is affected by non – plastic fines content. As fines content increase, cyclic shear strength decreases. Volumetric strain is influenced by fines content as well as shear strain and cyclic stress. At large shear strains amplitudes, an increase in percentage of fines causes more volumetric strains. Volumetric strains of silt samples are affected by cyclic shear stress more than sands

Total factor productivity and the role of entrepreneurship

Total factor productivity of twenty OECD countries for a recent period (1971-2002) is explained using six different models based on the established literature. Traditionally, entrepreneurship is not dealt with in these models. In the present paper it is shown that when this variable is added - in all models there is a significant influence of entrepreneurship while the remaining effects mainly stay the same. Entrepreneurship is measured as the business ownership rate (number of business owners per workforce) corrected for the level of economic development (GDP per capita)

The Investigation of Stability of Tunnels and Settlements with Centrifuge Modeling

In most of the larger cities underground transportation systems have been gettingdesired. Such systems are constructed in urban areas and involve a tunnel, especially in softground and in shallow zones.One of major concerns for tunneling operations in urban area is the effect onneighboring buildings, because the tunneling operation and near structures highly interacteach other. Whatever the used construction method is, the excavation of a tunnel causesdisplacement around the opening and may expand towards the ground surface. Thedislocations of the buildings interact with the ground movement, and the rigidity of existingstructures will promote reduction of the magnitude of displacements induced by tunneling.In this investigation, to determine displacements induced by tunneling, the centrifugemodeling was used. The small scale centrifuge model provided dependable information aboutthe face collapse of a shallow tunnel. A required support pressure for shield driven tunnels insoft materials, and the ground deformations along the longitudinal section of the tunnelmodel, can be identified by simulating a loss of tunnel face stability

Improving business processes of service companies

This article considers the problem of improving business process through analysis “Highlighting areas of concern”. In the process, we formulated a number of requirements that should meet the functionality of the information system and highlighted advantages of the"Selection concerns" method

Axions and saxions from the primordial supersymmetric plasma and extra radiation signatures

We calculate the rate for thermal production of axions and saxions via scattering of quarks, gluons, squarks, and gluinos in the primordial supersymmetric plasma. Systematic field theoretical methods such as hard thermal loop resummation are applied to obtain a finite result in a gauge-invariant way that is consistent to leading order in the strong gauge coupling. We calculate the thermally produced yield and the decoupling temperature for both axions and saxions. For the generic case in which saxion decays into axions are possible, the emitted axions can constitute extra radiation already prior to big bang nucleosynthesis and well thereafter. We update associated limits imposed by recent studies of the primordial helium-4 abundance and by precision cosmology of the cosmic microwave background and large scale structure. We show that the trend towards extra radiation seen in those studies can be explained by late decays of thermal saxions into axions and that upcoming Planck results will probe supersymmetric axion models with unprecedented sensitivity.Comment: 16 pages, 7 figures; v2: references added, minor clarifying additions, matches published versio

Human MLH1 deficiency predisposes to hematological malignancy and neurofibromatosis type 1

Heterozygous germ-line mutations in the DNA mismatch repair genes lead to hereditary nonpolyposis colorectal cancer. The disease susceptibility of individuals who constitutionally lack both wild-type alleles is unknown. We have identified three offspring in a hereditary nonpolyposis colorectal cancer family who developed hematological malignancy at a very early age, and at least two of them displayed signs of neurofibromatosis type 1 (NF1). DNA sequence analysis and allele-specific amplification in two siblings revealed a homozygous MLH1 mutation (C676T → Arg226Stop). Thus, a homozygous germ- line MLH1 mutation and consequent mismatch repair deficiency results in a mutator phenotype characterized by leukemia and/or lymphoma associated with neurofibromatosis type 1