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Tournaments, minimum wage, and money non-neutrality
No full textAbstract To reconstruct the micro-foundation of Keynesian macro-economics, the efficiency wage theory has generally been considered a success in providing a plausible explanation for the existence of involuntary unemployment. However, little has been said about how monetary policy causes fluctuations in aggregate employment and output in the efficiency wage theory. This paper extends Lin and Yang's [Econ. Inq. 39 (2001) 644] shirking-type efficiency wage model with tournaments to account for money non-neutrality. A distinct feature of our model is that, due to the adoption of tournaments, there will be a hierarchical wage structure rather than a flat wage in the economy. As will be argued, the labor market characterized in this paper is in a sense a reversion to Keynes' General Theory, but also an improvement upon it
High-throughput, multiplexed pushbroom hyperspectral microscopy References and links
No full textAbstract: We describe a high-throughput hyperspectral microscope. The system replaces the slit of conventional pushbroom spectral imagers with a static coded aperture mask. We present the theoretical underpinnings of the aperture coded spectral engine and describe two proof-of-concept experimental implementations. Compared to a conventional pushbroom system, the aperture coded systems have 32 times greater throughput. Both systems have about a 1nm spectral resolution over the spectral range of 550-665nm. For the first design, the spatial resolution for the system is 5.4μm, while the spatial resolution for the second system ranges from 7.7μm to 1.54μm. We describe experimental results from proof-of-concept applications of the imager to hyperspectral microscopy. 246-257 (1999). 9. C. Snively, G. Katzenberger, and J. Lauterbach, "Fourier-transform infrared imaging using a rapid-scan spectrometer," Opt. Lett. 24, 1841Lett. 24, -1843Lett. 24, (199
Size-Selected Nanoparticle Chemistry: Kinetics of Soot Oxidation
No full textA new experimental method has been developed to conduct surface chemistry and extract surface kinetic rates on size-selected nanoparticles. The method utilizes a tandem differential mobility analyzer (TDMA) technique in which monodisperse particles are selected from a polydisperse aerosol input stream and then subjected to chemical processing. The change in particle size is measured and used to determine kinetic information for the relevant surface reaction. The method has been applied to measure the oxidation rate of soot in air over the temperature range 800-1120°C. Soot was generated in situ using an ethylene diffusion flame and sent to a differential mobility analyzer (DMA) to extract monodisperse particles. Three initial particle sizes of 40, 93, and 130 nm mobility diameter were subjected to oxidation in a high-temperature flow reactor, and the resulting change in particle size was measured with a second DMA. The measured size decreases were fit to a model utilizing a modified Arrhenius expression for the rate of decrease: exp(-E a /(RT)). The fit yielded an activation energy of E a ) 164 kJ mol -1 with a different preexponential factor, A nm , for each initial particle size. The size-decrease rates, and therefore the preexponential factors, differed by a factor of 1.7 between the 40 and 130 nm particles, with the 130 nm particles decreasing faster than the 40 or 93 nm particles. This may be the result of several factors including different effective densities or different soot particle compositions. The current experiments are the first measurements of the soot oxidation rate to be performed on size-selected, freshly generated soot particles using online aerosol techniques. Our results agree well with previous work over the temperature range covered, which is somewhat surprising given the wide range of techniques and materials previously studied in the effort to understand soot oxidation
BLUE-GREEN ALGAE IN RICE FIELDS Their ecology an2 their use as inoculant
No full textAbstract This paper is a short review on blue-green algae in rice fields, their ecology and their use as inoculants. given to the recent studies of the relations between blue-green algae and rice which include the availability of algal nitrogen to the rice plant and epiphytic relationships. The paddy field ecosystem provides a favourable environment for the growth of BGA with respect to their requirements for light, water, high temperature and nutrient availability. BGA grow in higher abundance in paddy soils than in upland soils O0 The problem of the,choice of a density Òf sampling in relation to the distribitional ecology of algae had been studied by Roger and Reynaud (1978 N -fixation by BGA has been most frequently studied using the acetylene reducing activity method which may lead to erroneous results replicates and very frequent measurements are needed to ensure a satisfactory measure of total ARA. However, this tedious work will still lead to an imprecise evaluation of the nitrogen fixing activity (NFA) as the conversion factor acetylene-nitrogen is not constant and needs to be determined experimentally for each set of experimental conditions (Peterson and Burris, 1976). But ARA is a very convenient and reliable method for qualitative studies when the measurements are brief (David and Fay, 1977), when the problems of gas diffusion and greenhouse effects are minimized and when statistically valid sampling methods are adopted 2 Therefore, large number of Few reliable estimations of ARA have been hitherto published. The number of measurements and replicates have been generally too low. Moreover the importance of anaerobic non-heterocystous Nfixing BGA was not appreciated until recently and field measurements of nitrogenase activity were carried out under an aerobic gas phase only, therefore it is difficult to evaluate the N-input due to N -fixation by BGA (Stewart, 1978). 2- In areas with high incident light intensities, BGA develop later in the crop cycle when the plant cover is dense enough to protect them from excessive light (Roger and Reynaud, 1977). On the other hand, light deficiency may also be a limiting factor. In Japan, available light under the canopy was lower than the compensation point of the phytoplankton during the second part of the growth cycle O The optimal temperature for BGA is about 30-35 C, Temperature is rarely a limiting factor for BGA in paddy fields because the range of temperature permitting their growth is largar than that required by rice; however, temperature influences the composition of the algal biomass and the productivity. LOW temperatures decrease produckivity 102 f and favour eukaryotic algae: High temperatutes favour BGA and increase the algal productivity Soil properties Among the soil properties, pH is the most important factor determining the algal flora composition. grow preferentially in environments that are neutral to alkaline. submerged soils and noted that BGA growth was closely related to the available P content of the soil. The growth of N -fixing BGA in rice fields is most commonly 2 limited by low pH and P deficient, and application of P together with lime has frequently produced positive results . Biotic factors Organisms that limit BGA growth are: pathogens, antagonistic organisms and grazers. Of these, only grazers have been documented. The development of zooplankton populations, especially cladocerans, copepods, ostracods, and mosquito larvae prevented the establishment of algal blooms within one or two weeks (Venkataraman, 1961). Grazing rates and algal diet preferences of ostracods were studied by Grant and Alexander (1981) who estimated the potential consumption of BGA at an average field density of 10,000 ostracods m-2 to be about 120 kg (fw) ha-' day-'. ostracod populations is the application of crushed seeds of the neem tree (Azadirachta indica) (Grant et al., 1982 and soil after two crops (pot experiment, dried algae) showed that losses from 15N anmonium sulfate were more than twice than from BGA regardless of the mode of application. From these results the authors concluded that, due to its organic natuye, BGA material is less susceptible to nitrogen losses than inorganic fertilizer and that its low C/N ratio ( 5 -7 ) gives it a better nitrogen availability than those maturity, on the submerged weed Najas, and on deepwater rice could be observed only under the microscope and the dominant algae were Nostoc. Calothrix, and Anabaena. A unique finding was that BGA also exist .inside the cavities of senescent rice leaf sheaths; this "endophytism", however, in addition to being not confined to rice, was not present in living healthy tissues. A frequent observation was that older parts of the hosts and plants with rough surfaces supported more numerous epiphytic BGA. From these facts. it was concluded that epiphytism is possibly related to an abiotic effect, of which a mechanical effect in relation ta the roughness of the host surface appears to be of importance. The epiphytic alga'e on wetland rice at Rates of ARA on wetland rice gradually diminished from seedling to maturity mainly due to the concomitant decrease of Gloeotrichia epiphytism and the reduction of available light. In deepwater rice also there was a decrease in specific ARA (activity per gram of host) from heading to maturity but this was compensated by an increase in the host biomass so that a constant activity per plant was observed at In a field experiment, rice was grown fixation associated with deepwater rice was obtained by 2- The highest enrichments of 15N were found in sibmerged leaf sheaths where BGA grow epiphytically. During mg-N was fixed by the plant and'at maturity, about nodal roots and the 9 days period 8 40% of the fixed N 106 15 was found in parts of th.e plants not directly 'exposed to N2 In shallow water-rice, epiphytic BGA make only a small contribution to the nitrogen input, whereas, in deepwater rice they produce a substantial nitrogen input which is especially important because in this cropping system nitrogen fertilizer is seldom applied. ALGAL INCOULATION IN RICE FIELDS BGA were among the first N -fixing agents recognized to be Grain-yield measurements suggest that algalizatian produces both a cumulative and residual effect. This was attributed to a build up of both the organic N content and the number of BGA propagules in the soil, facilitating the reestablishment of the BGA biomass. Several reports indicate an increase in organic matter and organic N. Algalization was also reported to increase: aggregation status of the soil (Shield and Durrel, 1964). water-holding capacity (Singh, 1961). available P, and total microflora, Azotobacter, Clostridia, and nitrifiers . 4 . Limiting factors for algalization Among the possible limiting factors responsible for the failure of algalization-only pH and available P.content of the soil have been stud€ed. Since in some soils, algalization is inefficient in spite of the addition of lime and phosphate (Okuda and Yamaguchi, 1952). 108 available P content is probably not the only factor limiting the effect of algalization. On the other hand, texture, organic matter content, CEC of saturated extracts, and total N are probably no
The Toxic Effect of Manganese on the Acetylcholinesterase Activity in Rat Brains
No full textManganese (Mn) is a naturally occurring element and an essential nutrient for humans and animals. However, exposure to high levels of Mn may cause neurotoxic effects. Accumulation of manganese damages central nervous system and causes Parkinson's disease-like syndrome called manganism. Mn neurotoxicity has been suggested to involve an imbalance between the DAergic and cholinergic systems. The pathological mechanisms associated with Mn neurotoxicity are poorly understood, but several reports have established it is mediated by changing of AChE activity that resulted in oxidative stress. Therefore we focused the effect of Mn in AChE activity in the rat's brain by MnCl 2 injection intraperitoneally and analyzed their brains after time intervals. This study used different acute doses in short time course and different chronic doses at different exposing time to investigate which of them (exposing dose or time) is more important in Mn toxic effect. Results showed toxic effect of Mn is highly dose dependent and AChE activity in presence of chronic dose in 8 weeks reaches acute dose in only 2 days
No full textAbstract Detailed studies of the behaviour of positrons in selected room temperature molecular gases at densities below 1 amagat (≡ 2.69 × 10 25 molecules m −3 ) have allowed the isolation of two-and three-body effects upon the rate of annihilation. Investigations of gas mixtures have helped in removing ambiguities in the interpretation of the data noted in the first study of this phenomeno
Studies of the magnetic structure at the ferromagnet - antiferromagnet interface
No full textAbstract: Antiferromagnetic layers are a scientifically challenging component in magnetoelectronic devices such as magnetic sensors in hard disk heads, or magnetic RAM elements. In this paper we show that photo-electron emission microscopy (PEEM) is capable of determining the magnetic structure at the interface of ferromagnets and antiferromagnets with high spatial resolution (down to 20 nm). Dichroism effects at the L edges of the magnetic 3d transition metals, using circularly or linearly polarized soft x-rays from a synchrotron source, give rise to a magneti
AnAlysis of MAss-MediA Affected trAnsforMAtions of the dAnger concept
No full textThe article deals with a study of both short-term and long-term influence of massmedia upon a concept of danger (CD). Subjective concepts of danger (CD) were revealed by means of the authors "Assessment of Dangerous Situations" Questionnaire and a new classification of such concepts was developed. Demonstrated are differences in CD of men and women, as well as specific traits of CD transformations induced by news programs. The authors give advice on how to compile TV news programs in view of psychological mechanisms of perception
