545 research outputs found
Equalization and the Decentralization of Revenue-Raising in a Federation
We study federal economies in which regional governments have responsibility for delivering public services and redistributive objectives apply. The implications of these for the assignment of revenue-raising instruments and fiscal transfers, both vertical and horizontal, are considered. Models of heterogenous regions of varying degrees of complexity and generality are constructed. For each case, we determine what fiscal instruments must be given to the regions and what inter-governmental transfers must be made in order that the social optimum is achieved. With heterogenous households and regions, the social optimum can be decentralized by making regions responsible for redistribution and implementing equalization transfers that depend on the number of households of each type.
Solar radiation induced damage to optical properties of ZnO-type pigments Technical summary report, Jun. 27, 1966 - Mar. 27, 1967
Degradation model of solar radiation damage to optical properties of zinc oxide pigments used for spacecraft thermal control coating
Support for public provision of a private good with top-up and opt-out: A controlled laboratory experiment
This paper presents the results of a revealed-choice experiment testing the theoretical predictions of political economy models regarding public support for a publicly provided private good financed with proportional income taxes when individuals can purchase the good privately and either continue to consume public provision (‘top-up’) or forego public provision (‘opt-out’), but in each case continue to pay income taxes. Our laboratory results confirm behavior is consistent with the predicted majority-preferred tax rate under mixed financing with top-up, but we identify preferences for significantly higher rates of public provision than predicted under mixed financing with opt-out. Using non parametric regression analysis, we explore the relationship between individuals’ top-up and opt-out decisions and both their income levels and the implemented tax rates
Structural and electronic properties of Pb1-xCdxTe and Pb1-xMnxTe ternary alloys
A systematic theoretical study of two PbTe-based ternary alloys, Pb1-xCdxTe
and Pb1-xMnxTe, is reported. First, using ab initio methods we study the
stability of the crystal structure of CdTe - PbTe solid solutions, to predict
the composition for which rock-salt structure of PbTe changes into zinc-blende
structure of CdTe. The dependence of the lattice parameter on Cd (Mn) content x
in the mixed crystals is studied by the same methods. The obtained decrease of
the lattice constant with x agrees with what is observed in both alloys. The
band structures of PbTe-based ternary compounds are calculated within a
tight-binding approach. To describe correctly the constituent materials new
tight-binding parameterizations for PbTe and MnTe bulk crystals as well as a
tight-binding description of rock-salt CdTe are proposed. For both studied
ternary alloys, the calculated band gap in the L point increases with x, in
qualitative agreement with photoluminescence measurements in the infrared. The
results show also that in p-type Pb1-xCdxTe and Pb1-xMnxTe mixed crystals an
enhancement of thermoelectrical power can be expected.Comment: 10 pages, 13 figures, submitted to Physical Review
Relating neuromuscular control to functional anatomy of limb muscles in extant archosaurs
Electromyography (EMG) is used to understand muscle activity patterns in animals. Understanding how much variation exists in muscle activity patterns in homologous muscles across animal clades during similar behaviours is important for evaluating the evolution of muscle functions and neuromuscular control. We compared muscle activity across a range of archosaurian species and appendicular muscles, including how these EMG patterns varied across ontogeny and phylogeny, to reconstruct the evolutionary history of archosaurian muscle activation during locomotion. EMG electrodes were implanted into the muscles of turkeys, pheasants, quail, guineafowl, emus (three age classes), tinamous and juvenile Nile crocodiles across 13 different appendicular muscles. Subjects walked and ran at a range of speeds both overground and on treadmills during EMG recordings. Anatomically similar muscles such as the lateral gastrocnemius exhibited similar EMG patterns at similar relative speeds across all birds. In the crocodiles, the EMG signals closely matched previously published data for alligators. The timing of lateral gastrocnemius activation was relatively later within a stride cycle for crocodiles compared to birds. This difference may relate to the coordinated knee extension and ankle plantarflexion timing across the swing‐stance transition in Crocodylia, unlike in birds where there is knee flexion and ankle dorsiflexion across swing‐stance. No significant effects were found across the species for ontogeny, or between treadmill and overground locomotion. Our findings strengthen the inference that some muscle EMG patterns remained conservative throughout Archosauria: for example, digital flexors retained similar stance phase activity and M. pectoralis remained an ‘anti‐gravity’ muscle. However, some avian hindlimb muscles evolved divergent activations in tandem with functional changes such as bipedalism and more crouched postures, especially M. iliotrochantericus caudalis switching from swing to stance phase activity and M. iliofibularis adding a novel stance phase burst of activity
Voronoia: analyzing packing in protein structures
The packing of protein atoms is an indicator for their stability and functionality, and applied in determining thermostability, in protein design, ligand binding and to identify flexible regions in proteins. Here, we present Voronoia, a database of atomic-scale packing data for protein 3D structures. It is based on an improved Voronoi Cell algorithm using hyperboloid interfaces to construct atomic volumes, and to resolve solvent-accessible and -inaccessible regions of atoms. The database contains atomic volumes, local packing densities and interior cavities calculated for 61 318 biological units from the PDB. A report for each structure summarizes the packing by residue and atom types, and lists the environment of interior cavities. The packing data are compared to a nonredundant set of structures from SCOP superfamilies. Both packing densities and cavities can be visualized in the 3D structures by the Jmol plugin. Additionally, PDB files can be submitted to the Voronoia server for calculation. This service performs calculations for most full-atomic protein structures within a few minutes. For batch jobs, a standalone version of the program with an optional PyMOL plugin is available for download. The database can be freely accessed at: http://bioinformatics.charite.de/voronoia
Two novel human cytomegalovirus NK cell evasion functions target MICA for lysosomal degradation
NKG2D plays a major role in controlling immune responses through the regulation of natural killer (NK) cells, αβ and γδ T-cell function. This activating receptor recognizes eight distinct ligands (the MHC Class I polypeptide-related sequences (MIC) A andB, and UL16-binding proteins (ULBP)1–6) induced by cellular stress to promote recognition cells perturbed by malignant transformation or microbial infection. Studies into human cytomegalovirus (HCMV) have aided both the identification and characterization of NKG2D ligands (NKG2DLs). HCMV immediate early (IE) gene up regulates NKGDLs, and we now describe the differential activation of ULBP2 and MICA/B by IE1 and IE2 respectively. Despite activation by IE functions, HCMV effectively suppressed cell surface expression of NKGDLs through both the early and late phases of infection. The immune evasion functions UL16, UL142, and microRNA(miR)-UL112 are known to target NKG2DLs. While infection with a UL16 deletion mutant caused the expected increase in MICB and ULBP2 cell surface expression, deletion of UL142 did not have a similar impact on its target, MICA. We therefore performed a systematic screen of the viral genome to search of addition functions that targeted MICA. US18 and US20 were identified as novel NK cell evasion functions capable of acting independently to promote MICA degradation by lysosomal degradation. The most dramatic effect on MICA expression was achieved when US18 and US20 acted in concert. US18 and US20 are the first members of the US12 gene family to have been assigned a function. The US12 family has 10 members encoded sequentially through US12–US21; a genetic arrangement, which is suggestive of an ‘accordion’ expansion of an ancestral gene in response to a selective pressure. This expansion must have be an ancient event as the whole family is conserved across simian cytomegaloviruses from old world monkeys. The evolutionary benefit bestowed by the combinatorial effect of US18 and US20 on MICA may have contributed to sustaining the US12 gene family
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