1,115 research outputs found
Labor Supply Prediction when Tax Avoidance Matters
We examine how tax avoidance in the form of trade in well-functioning asset markets affects the empirical study of labor supply. We discuss the implications for tax policy analysis, and we show that a failure to account for avoidance responses may lead to huge errors when predicting how tax reform affects labor supply tax revenue, and the welfare cost of taxation. In conclusion we argue that our model may explain a number of otherwise hard to understand dimensions of tax payer response.Labor supply; tax avoidance; asset markets; tax reform simulation
Labor Supply When Tax Avoidance Matters
We examine how tax avoidance in the form of trade in well-functioning asset markets affects the empirical study of labor supply. We discuss the implications for tax policy analysis, and we show that a failure to account for avoidance responses may lead to huge errors when predicting how tax reform affects labor supply, tax revenue, and the welfare cost of taxation. In conclusion we argue that our model may explain a number of otherwise hard to understand dimensions of tax payer response.Labour supply; Tax avoidance; Asset markets; Tax reform simulation
Self-energy correction to the hyperfine structure splitting of hydrogenlike atoms
A first testing ground for QED in the combined presence of a strong Coulomb field and a strong magnetic field is provided by the precise measurement of the hyperfine structure splitting of hydrogenlike 209Bi. We present a complete calculation of the one-loop self-energy correction to the first-order hyperfine interaction for various nuclear charges. In the low-Z regime we almost perfectly agree with the Z alpha expansion, but for medium and high Z there is a substantial deviation
Effects of Complex Vertebral Malformation on Fertility in Swedish Holstein Cattle
Complex vertebral malformation (CVM) is an autosomal recessive inherited defect in the Holstein breed. It causes intra-uterine mortality through the entire gestation period leading to repeat breeding and involuntary culling of cows and thereby economic losses. The defect was first reported in Denmark in 1999 and a direct DNA test for the defect has been available since February 2001. The aim of this study was to investigate if Holstein bulls heterozygous for the CVM gene had reduced reproductive performance, measured as non-return rate (NRR) and in a daughter fertility index. All genotyped Swedish Holstein bulls born between 1995 and 1999 were included. Altogether 228 bulls were analysed, of which 53 bulls, i.e. 23%, were confirmed CVM carriers. A statistically significant difference between carriers and non-carriers in the relative breeding value for NRR was observed for 168 days NRR (101.1 ± 0.9 vs. 103.1 ± 0.6, p < 0.05). There was no difference for 28 days NRR whereas the difference approached significance for 56 days NRR. No significant effect of the paternal CVM genotype on the daughter fertility index was shown probably due to the complexity of traits this index is composed of. In conclusion, the study showed that carriers of the CVM defect have an inferior NRR compared with non-carriers
Subdivision of the MDR superfamily of medium-chain dehydrogenases/reductases through iterative hidden Markov model refinement
<p>Abstract</p> <p>Background</p> <p>The Medium-chain Dehydrogenases/Reductases (MDR) form a protein superfamily whose size and complexity defeats traditional means of subclassification; it currently has over 15000 members in the databases, the pairwise sequence identity is typically around 25%, there are members from all kingdoms of life, the chain-lengths vary as does the oligomericity, and the members are partaking in a multitude of biological processes. There are profile hidden Markov models (HMMs) available for detecting MDR superfamily members, but none for determining which MDR family each protein belongs to. The current torrential influx of new sequence data enables elucidation of more and more protein families, and at an increasingly fine granularity. However, gathering good quality training data usually requires manual attention by experts and has therefore been the rate limiting step for expanding the number of available models.</p> <p>Results</p> <p>We have developed an automated algorithm for HMM refinement that produces stable and reliable models for protein families. This algorithm uses relationships found in data to generate confident seed sets. Using this algorithm we have produced HMMs for 86 distinct MDR families and 34 of their subfamilies which can be used in automated annotation of new sequences. We find that MDR forms with 2 Zn<sup>2+ </sup>ions in general are dehydrogenases, while MDR forms with no Zn<sup>2+ </sup>in general are reductases. Furthermore, in Bacteria MDRs without Zn<sup>2+ </sup>are more frequent than those with Zn<sup>2+</sup>, while the opposite is true for eukaryotic MDRs, indicating that Zn<sup>2+ </sup>has been recruited into the MDR superfamily after the initial life kingdom separations. We have also developed a web site <url>http://mdr-enzymes.org</url> that provides textual and numeric search against various characterised MDR family properties, as well as sequence scan functions for reliable classification of novel MDR sequences.</p> <p>Conclusions</p> <p>Our method of refinement can be readily applied to create stable and reliable HMMs for both MDR and other protein families, and to confidently subdivide large and complex protein superfamilies. HMMs created using this algorithm correspond to evolutionary entities, making resolution of overlapping models straightforward. The implementation and support scripts for running the algorithm on computer clusters are available as open source software, and the database files underlying the web site are freely downloadable. The web site also makes our findings directly useful also for non-bioinformaticians.</p
Test of an empirical method for ozone detection in the stratosphere using two filtered broadband UV-meters
We describe a simple method to detect significant changes of the total ozone column from global (diffuse and direct) zenith sky measurements taken at the Earthâs surface. The calculation of the total ozone column relies on measured irradiance at two wavelengths in the ultra violet part of the solar spectrum. One of these (i.e. 306 nm) are appreciable absorbed by ozone whereas the other (i.e. 360 nm) is not. The method provides measurements for clear as well as for cloudy sky conditions. The natural logarithm of the irradiance ratio at the two wavelengths, corrected for solar elevation dependence, is assumed to be proportional to the amount of ozone in the atmospheric column. It is assumed that the two wavelengths have same properties in the atmosphere excluding the impact of ozone. Therefore variations in atmospheric conditions should cancel out in the ratio. We found a strong correlation between our calculated quantity and ozone measurements at The Danish Meteorological Institute, DMI, Copenhagen, Denmark, which is approximately 30 km away from the measuring site. The correlation coefficient, R, from linear regression had the value 0.90, and the standard deviation, Sres, for the residuals were 10.6 DU (Dobson Units), and the mean value was 322 DU, obtained from every day point measurements during the Swedish summer, total 67 days
Influence of Plastic Dissipation on Apparent Fracture Energy Determined by a Three-Point Beding Test
A three-point bending test used for determining the fracture energy in modus I for wood perpendicular to the grain is studied, If the height of the specimen is varied, the results show a size effect, The specimens used in testing have been analyzed by finite element calculations with an anisotropic elasto-plastic material model in order to determine the influence of plastic dissipation. Analysis has been performed for three sizes of specimens where the height and length have been varied. The computational results are compared with experimental results
Three genes expressing Kunitz domains in the epididymis are related to genes of WFDC-type protease inhibitors and semen coagulum proteins in spite of lacking similarity between their protein products
<p>Abstract</p> <p>Background</p> <p>We have previously identified a locus on human chromosome 20q13.1, encompassing related genes of postulated WFDC-type protease inhibitors and semen coagulum proteins. Three of the genes with WFDC motif also coded for the Kunitz-type protease inhibitor motif. In this report, we have reinvestigated the locus for homologous genes encoding Kunitz motif only. The identified genes have been analyzed with respect to structure, expression and function.</p> <p>Results</p> <p>We identified three novel genes; <it>SPINT3, SPINT4 </it>and <it>SPINT5</it>, and the structure of their transcripts were determined by sequencing of DNA generated by rapid amplification of cDNA ends. Each gene encodes a Kunitz domain preceded by a typical signal peptide sequence, which indicates that the proteins of 7.6, 8.7, and 9.7 kDa are secreted. Analysis of transcripts in 26 tissues showed that the genes predominantly are expressed in the epididymis. The recombinantly produced proteins could not inhibit the amidolytic activity of trypsin, chymotrypsin, plasmin, thrombin, coagulation factor Xa, elastase, urokinase and prostate specific antigen, whereas similarly made bovine pancreatic trypsin inhibitor (BPTI) had the same bioactivity as the protein isolated from bovine pancreas.</p> <p>Conclusions</p> <p>The similar organization, chromosomal location and site of expression, suggests that the novel genes are homologous with the genes of WFDC-type protease inhibitors and semen coagulum proteins, despite the lack of similarity in primary structure of their protein products. Their restricted expression to the epididymis suggests that they could be important for male reproduction. The recombinantly produced proteins are presumably bioactive, as demonstrated with similarly made BPTI, but may have a narrower spectrum of inhibition, as indicated by the lacking activity against eight proteases with differing specificity. Another possibility is that they have lost the protease inhibiting properties, which is typical of Kunitz domains, in favor of hitherto unknown functions.</p
Time-resolved laser spectroscopy on high-lying states in neutral oxygen
Radiative lifetimes have been measured for five triplet states of atomic oxygen. The oxygen atoms were generated by photodissociation of NO2 and the investigated states were populated through a two-step process involving a two-photon excitation to the lowest excited triplet state of even parity, 2p33p 3P, followed by a one-photon excitation to the investigated state. A similar scheme is applicable to the study of excited states in many light atoms
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