Analysis of the Systematic Errors Found in the Kipp & Zonen Large-Aperture Scintillometer

Studies have shown a systematic error in the Kipp & Zonen large-aperture scintillometer (K&ZLAS) measurements of the sensible heat flux, H. We improved on these studies and compared four K&ZLASs with a Wageningen large-aperture scintillometer at the Chilbolton Observatory. The scintillometers were installed such that their footprints were the same and independent flux measurements were made along the measurement path. This allowed us to compare H and the direct scintillometer output, the refractive index structure parameter, C2n. Furthermore, spectral analysis was performed on the raw scintillometer signal to investigate the characteristics of the error. Firstly, correlation coefficients =0.99 confirm the robustness of the scintillometer method, and secondly we discovered two systematic errors: the low-C2n error and the high-C2n error. The low-C2n error is a non-linear error that is caused by high-frequency noise, and we suspect the error to be caused by the calibration circuit in the receiver. It varies between each K&ZLAS, is significant for H = 50 W m-2, and we propose a solution to remove this error using the demodulated signal. The high-C2n error identified by us is the systematic error found in previous studies.We suspect this error to be caused by poor focal alignment of the receiver detector and the transmitter light-emitting diode that causes ineffective use of the Fresnel lens in the current Kipp & Zonen design. It varies between each K&ZLAS (35% up to 240%) and can only be removed by comparing with a reference scintillometer in the field

3D spectroscopy of dwarf elliptical galaxies

I present some results of 3D spectroscopy for a small sample of dwarf elliptical galaxies, mostly members of small groups. The galaxies under consideration have a typical absolute magnitude of -18 (B-band), and at the Kormendy's relation they settle within a transition zone between the main cloud of giant ellipticals and the sequence of diffuse ellipticals. By measuring Lick indices and investigating radial profiles of the SSP-equivalent ages and metallicities of the stellar populations in their central parts, I have found evolutionary distinct cores in all of them. Typically, the ages of these cores are 2-4 Gyr, and the metallicities are higher than the solar one. Outside the cores, the stellar populations are always old, T>12 Gyr, and the metallicities are subsolar. This finding implies that the well-known correlation between the stellar age and the total mass (luminosity) of field ellipticals (Trager et al. 2000, Caldwell et al. 2003, Howell 2005) may be in fact a direct consequence of a larger contribution of nuclear starbursts into the integrated stellar population in dwarfs with respect to giants, and does not relate to `downsizing'.Comment: 2 pages, 1 figure. Poster contribution to the proceedings of the conference "A Universe of Dwarf Galaxies" (Lyon, June 14-18, 2010

On the dispersion of fundamental particles in QCD and N=4 Super Yang-Mills theory

We study thermal corrections to the dispersion relations of massive fundamental particles immersed in weakly coupled non-Abelian plasmas. The cases covered include quarks in the QCD (quark-gluon) plasma, as well as N=2 quarks and scalars in an N=4 Super Yang-Mills plasma. We perform the calculations to leading order in a weak coupling expansion, and consider all mass scales of the fundamental fields, ranging from massless particles all the way to bare masses parametrically larger than the temperature.Comment: 41 pages, 8 figures; v2 to be published in JHEP, with one table added to summarize result

THE ROLE OF THE TOURISM SECTOR IN THE DIGITALIZATION OF THE SERVICE ECONOMY

This article describes the role of tourism in the digitalization of the services economy. In line with global trends, the development of science and technology, information technology and telecommunications systems in Uzbekistan is leading to the development of the service sector, and tourism is becoming a significant sector in the digitalization of the service economy

The elderly in rural Ghana: health-care needs and challenges

The health-care needs of elderly persons who live in rural areas of Ghana are considered. Brief socio-demographic information on the population is given. Barriers and challenges to the provision of health care to the population are examined. The Ghanaian pluralistic health system is described briefly. Finally, measures are proposed to meet the challenges of providing health care to the elderly rural population

Retirement policies and economic security for older people in Africa

Major features and limitations of social insurance and retirement programmes in Africa are examined. The relationship between formal and informal security systems is explored and the role of communities, non-governmental organizations and employer-based private pension schemes for retired older Africans is highlighted. In addition, social, health, gender inequity and long-term care services are discussed, the provision of which could enhance the well-being of older Africans

PRE AND POST HARVEST STUDIES OF YAM DISEASES AND THEIR CONTROL MEASURE IN SOUTH EASTERN NIGERIA

Yam, (Dioscorea spp) is the most important food crop and source of income for millions of producers, processors and consumers in West Africa. In Nigeria, its production is constrained by many problems such as high cost of production, nematodes attack, vertebrate pests and pathogens singly or in combination. They are all responsible for field suppression and tuber quality deterioration in storage. Though yam tuber naturally has a periderm, microorganism that cannot get into, it is easily wounded by rodents, nematodes and man during field operation including weeding, harvesting and post-harvest handling. The wounds make room for the penetration and development of rot microorganism. The magnitude of these problems has made many to express fear that yam production in Nigeria may decline substantially in the near future. Due to all these problems of yam during pre and post-harvest, there should be a thorough control measure for both farmers and scientists to mitigate loss of yams both in the field and in the store (Barn). Some research has been conducted to test the potency of some plant extracts for the control of yam tuber rot caused by Fusarium oxysporum, Aspergillus niger and Aspergillus flavus. It was found that hot water extracts were obtained from leaf and seed of uda (Xylopia aethiopica) and Ginger (Zinigiber officinale), and were found during harvest, to be fungi-toxic against the fungi

Galactic disks and their evolution

We consider the key problems related to measuring the mass of stellar disks and dark halos in galaxies and to explaining the observed properties of disks formed in massive dark halos.Comment: 6 pages, 2 figure

Weak production of strangeness at threshold with polarization observables

AbstractThe differential cross section for the charged current electroweak reaction e→+p→ν→e+Λ→ at threshold with polarization observables is presented. The form of the cross section at threshold for the reaction is simplified compared to higher energy. An expression is given for the invariant matrix element appropriate for the reaction when the incident electron is polarized, and the final state hyperon polarization is determined. The energy dependence of the resulting cross section is shown near threshold. Under the right kinematic conditions, there can be a sizeable enhancement in the cross section, making an experimental measurement of the weak axial-vector form factor feasible

Підсумки інтродукції видів Tilia L. в умовах Києва

Seventin species and three forms of Tilia L. were introduced in arboretum of NBG of the NAS of Uk  raine. As a result five species, to wit T. platyphyllos Scop., T. europaea L., T. begoniifolia Stev., T. dasystyla Stev. аnd T. neglecta Spach. were recommended for use. It was cited the species for study and testing and some species, which must be limited for use.Підбито підсумки інтродукції 17 видів і трьох форм Tilia L. в дендрарії НБС НАН України. Для широкого застосування в озелененні поряд з липою серцелистою рекомендовано ще п’ять видів – липу широколисту, європейську, кавказьку, пухнастостовпчикову та забуту. Виявлено види, що потребують подальшого вивчення і випробування, а також ті, чиє використання потрібно обмежити