Current and Shot Noise Measurements in a Carbon Nanotube-Based Spin Diode

Low-temperature measurements of asymmetric carbon nanotube (CNT) quantum dots are reported. The CNTs are end-contacted with one ferromagnetic and one normal-metal electrode. The measurements show a spin-dependent rectification of the current caused by the asymmetry of the device. This rectification occurs for gate voltages for which the normal-metal lead is resonant with a level of the quantum dot. At the gate voltages at which the current is at the maximum current, a significant decrease in the current shot noise is observed

Ispitivanje antioksidativnih mehanizama kempferola sa hidroksi radikalom i superoksid radikal anjonom

Kaempferol, one of the most bioactive plant flavonoids was theoretically (at M05-2X/6-311G(d,p) level of theory) investigated for its ability scavange potentially highly damaging hydroxyl and superoxide anion radicals. Theoretical calculations point to HAT and SPLET mechanisms as operative for kaempferol in all solvents under investigations.Teoretski (na M05-2X/6-311G(d,p) nivou teorije) je ispitivana sposobnost kempferola, važnog bioaktivnog biljnog jedinjenja flavonoida, da reaguje sa potencijalno veoma štetnim hidroksi radikalom i superoksid radikal anjonom. Proračuni su pokazali da su HAT i SPLET mogući mehanizmi u svim rastvaračima

Why should gender differences in hospitality really matter? A study of personnel’s service orientation and job satisfaction in hotels

In this article we examine the gender differences among hotel employees in service orientation and job satisfaction. To determine these differences, we used a service orientation scale (SOS), developed by Dienhart, Gregoire, Downey and Knight and a job satisfaction scale developed by Lytle. Our assumptions were that there would be significant gender differences in service orientation and job satisfaction. Our research proved factor structures of the two scales we used. Specifically, we showed gender differences in two of three factors, concerning service orientation (organisational support and customer focus), and no gender differences in job satisfaction. Our study revealed that organisational support is more important to men because they value more structured labour and service procedures than women (t = 2.21, df = 110, p = 0.03). In contrast, customer focus is more relevant to a women because it is more crucial to see satisfied guests, as well as having a good relationship with them (t = 2.07, df = 110, p = 0.04). It is of great importance for hotel management to have in mind that male and female employees respond and behave differently depending on the stimuli in the work environment and their satisfaction varies because of it

Sustainable Tourism as a Part of Comprehensive Environmental Monitoring. A Study of Serbia

The sustainable tourism comprises the freedom of tourist travelling, satisfying the economic, social and aesthetic needs, with the preservation of the characteristics of the natural and social environment and the cultural and historical heritage. It should optimize the usage of environmental resources that make the key element of tourism development, maintaining the essential ecologic processes and helping in heritage preservation, and providing the sustainable long-term business.As the consequences of the anthropogenic activities are obvious in the deterioration of the environment quality, the analysis of the status and influence on the environment and humans, as well as on the flora and fauna, must be under constant monitoring. The aim is to detect the corresponding influences and changes and to establish their cause. The paper approaches the structure, the processes and the application of the comprehensive monitoring of the environment with the aim of creating a database for the development of sustainable tourism in Serbia. The risk of the anthropogenic pollution of the environment, as a result of tourist activities, and monitoring of these activities in order to create a database for a planned and coordinated activity of tourism development will be considered in detail

A semi empirical formula for the angular differential number albedo of low-energy photons

Low-energy photon reflection from water, aluminum, and iron is simulated by the MCNP code and results are com pared with similar Monte Carlo calculations. For the energy range from 60 to 150 keV and for the normal incidence of initial photons, a universal shape of the normalized angular differential number albedo is observed and after that fitted by the curve fit ting procedure in form of a second order polynomial over the polar angle. Finally, a one-parameter formula for the angular differential number albedo is developed and verified for water through the comparison of results with the semi empirical formulae and Monte Carlo calculations of other authors

Effects of induced maternal hypothyroidism on the ovarian development of offspring rats

The effects of propylthyouracil (PTU) induced hypothyroidism of rats during pregnancy and lactation on offspring ovarian development and maturation were studied. Thyroid hormones and thyroid stimulating hormone (TSH) concentrations were determined using the radioimmunoassay method in order to verify the hypothyroid status of treated mothers and their two months old pups. The ovaries of the offspring were processed for light microscopy analysis on the day of the first estrus after the 60th day of age. Histological analysis including follicle count was performed on serial sections stained with haematoxyline/eosin and on semithin sections stained with methylene blue. A significant increase of serum TSH and decrease in T3 and T4 levels was observed in treated mothers compared to controls. The levels of measured hormones in the control and PTU-treated two months old rats were not significantly different. Ten percent of 60-dayold treated females did not reach estrus and they were sacrificed in diestrus. The secondary interstitial cells were the dominant structures in the ovaries. The number of healthy growing and early antral follicles was markedly decreased. Ovaries of treated rats contained relatively few antral follicles, significantly more atretic antral follicles and a decreased number of corpora lutea, compared to controls. These results indicate that lack of thyroid hormones during prenatal and early postnatal development impair ovarian development in rats. [Projekat Ministarstva nauke Republike Srbije, br. 175061

Carbonized Jute Sorbent for Oil Cleanup

Over 90 million tons of textile waste is produced every year. A large share of waste comes from the goods made of cellulose fibers. Recently, special attention has been directed towards the use of textile cellulose waste for clean-up of oil spills. The major problem relies on their relatively small oil capacity and complex separation of individual cellulose fibers from the treated spills. In an attempt to overcome this drawback, a non-woven sorbent based on recycled jute fibers obtained from the carpet industry was manufactured. Improvement of porosity and hydrophobicity/oleophilicity of the sorbent was achieved by carbonization process in an inert atmosphere. FESEM analysis revealed the fiber reduction of almost 40% induced by fiber degradation while EDX analysis confirmed the increase in the carbon content by 75% after carbonization. Oil capacity in water medium, buoyancy, oil retention and reusability of non-carbonized and carbonized sorbents were evaluated by testing four different oils (crude oil, diesel oil, two motor oils). After carbonization process, the oil sorption capacity was doubled in comparison with noncarbonized sorbent independent of oil viscosity. Carbonized sorbent not only remained afloat after 24 h of staying in water, but it sorbed a negligible amount of water unlike non-carbonized sorbent. in addition to good buoyancy, oil retention on carbonized sorbents ranged from 64-80% after 30 min of draining. Larger uptake was achieved with oils of higher viscosity, but their retention was worse. Oil sorption capacity after 5 repeated sorption/desorption trials was significantly larger in the case of carbonized sorbent since it retained 80-88% of its initial oil sorption capacity depending on tested oil