10,812 research outputs found
Limiting Government Predation Through Anonymous Banking: A Theory with Evidence from China
China's economic performance of the past two decades presents a puzzle for the economics of transition and development: Enormous private business incentives were unleashed that have fueled rapid economic growth despite the fact that China has had very weak "conventional institutions" (such as the rule of law and separation of powers) to constrain the government from arbitrary intrusion into economic activities. We argue that one mechanism that has limited the government's ability for predation and harassment is commitment through information decentralization, where the key institutiton is "anonymous banking," that is, a combination of the use of cash for transactions and the use of anonymous savings deposits. The government's incentive for such a mechanism comes form the increased quasi-fiscal revenues collected from the state banking system through "financial repression," a combination of controls on international capital flows with restrictions on domestic interest rates. The major features of China's economy concerning its fiscal decline, financial deepening, and the sectoral dual-track can be better understood using this analytical framework.http://deepblue.lib.umich.edu/bitstream/2027.42/39659/3/wp275.pd
Limiting Government Predation Through Anonymous Banking: A Theory with Evidence from China
China's economic performance of the past two decades presents a puzzle for the economics of transition and development: Enormous private business incentives were unleashed that have fueled rapid economic growth despite the fact that China has had very weak "conventional institutions" (such as the rule of law and separation of powers) to constrain the government from arbitrary intrusion into economic activities. We argue that one mechanism that has limited the government's ability for predation and harassment is commitment through information decentralization, where the key institutiton is "anonymous banking," that is, a combination of the use of cash for transactions and the use of anonymous savings deposits. The government's incentive for such a mechanism comes form the increased quasi-fiscal revenues collected from the state banking system through "financial repression," a combination of controls on international capital flows with restrictions on domestic interest rates. The major features of China's economy concerning its fiscal decline, financial deepening, and the sectoral dual-track can be better understood using this analytical framework.
Digital Natives and Digital Immigrants - Towards a Model of Digital Fluency
The article looks at the differences between âdigital nativesâ and âdigital immigrants.â Digital natives are the new generation of young people born into the digital age, while âdigital immigrantsâ are those who learnt to use computers at some stage during their adult life. Whereas digital natives are assumed to be inherently technologysavvy, digital immigrants are usually assumed to have some difficulty with information technology. The paper suggests that there is a continuum rather than a rigid dichotomy between digital natives and digital immigrants, and this continuum is best conceptualized as digital fluency. Digital fluency is the ability to reformulate knowledge and produce information to express oneself creatively and appropriately in a digital environment. The authors propose a tentative conceptual model of digital fluency that outlines factors that have a direct and indirect impact on digital fluency namely, demographic characteristics, organizational factors, psychological factors, social influence, opportunity, behavioral intention and actual use of digital technologies
Inhomogeneous ferrimagnetic-like behavior in Gd2/3Ca1/3MnO3 single crystals
We present a study of the magnetic properties of Gd2/3Ca1/3MnO3 single
crystals at low temperatures. We show that this material behave as an
inhomogeneous ferrimagnet. In addition to small saturation magnetization at 5
K, we have found history dependent effects in the magnetization and the
presence of exchange bias. These features are compatible with microscopic phase
separation in the clean Gd2/3Ca1/3MnO3 system studied.Comment: 7 pages, 6 figures, submitted Journal of Magnetism and Magnetic
Material
Establishment of Clonal MIN-O Transplant Lines for Molecular Imaging via Lentiviral Transduction & In Vitro Culture
As the field of molecular imaging evolves and increasingly is asked to fill the discovery and validation space between basic science and clinical applications, careful consideration should be given to the models in which studies are conducted. The MIN-O mouse model series is an established in vivo model of human mammary precancer ductal carcinoma in situ with progression to invasive carcinoma. This series of transplant lines is propagated in vivo and experiments utilizing this model can be completed in non-engineered immune intact FVB/n wild type mice thereby modeling the tumor microenvironment with biological relevance superior to traditional tumor cell xenografts. Unfortunately, the same qualities that make this and many other transplant lines more biologically relevant than standard cell lines for molecular imaging studies present a significant obstacle as somatic genetic re-engineering modifications common to many imaging applications can be technically challenging. Here, we describe a protocol for the efficient lentiviral transduction of cell slurries derived from precancerous MIN-O lesions, in vitro culture of âMIN-O-spheresâ derived from single cell clones, and the subsequent transplantation of these spheres to produce transduced sublines suitable for optical imaging applications. These lines retain the physiologic and pathologic properties, including multilineage differentiation, and complex microanatomic interaction with the host stroma characteristic of the MIN-O model. We also present the in vivo imaging and immunohistochemical analysis of serial transplantation of one such subline and detail the progressive multifocal loss of the transgene in successive generations
An ultra-luminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30
So far, roughly 40 quasars with redshifts greater than z=6 have been
discovered. Each quasar contains a black hole with a mass of about one billion
solar masses (). The existence of such black holes when the
Universe was less than 1 billion years old presents substantial challenges to
theories of the formation and growth of black holes and the coevolution of
black holes and galaxies. Here we report the discovery of an ultra-luminous
quasar, SDSS J010013.02+280225.8, at redshift z=6.30. It has an optical and
near-infrared luminosity a few times greater than those of previously known z>6
quasars. On the basis of the deep absorption trough on the blue side of the Ly
emission line in the spectrum, we estimate the proper size of the
ionized proximity zone associated with the quasar to be 26 million light years,
larger than found with other z>6.1 quasars with lower luminosities. We estimate
(on the basis of a near-infrared spectrum) that the black hole has a mass of
, which is consistent with the derived by assuming an Eddington-limited accretion rate.Comment: 24 pages, 4 figures plus 4 extended data figures, published in Nature
on 26 February 201
Polyurea-Functionalized Multiwalled Carbon Nanotubes
An in situ polycondensation approach was applied to functionalize multiwalled carbon nanotubes (MWNTs), resulting in various linear or hyperbranched polycondensed polymers [e.g., polyureas, polyurethanes, and poly(urea-urethane)-bonded carbon nanotubes]. The quantity of the grafted polymer can be easily controlled by the feed ratio of monomers. As a typical example, the polyurea-functionalized MWNTs were measured and characterized in detail. The oxidized MWNTs (MWNT-COOH) were converted into acyl chloride-functionalized MWNTs (MWNT-COCl) by reaction with neat thionyl chloride (SOCl2). MWNT-COCl was reacted with excess 1,6-diaminohexane, affording amino-functionalized MWNTs (MWNT-NH2). In the presence of MWNT-NH2, the polyurea was covalently coated onto the surfaces of the nanotube by in situ polycondensation of diisocyanate [e.g., 4,4â-methylenebis(phenylisocyanate)] and 1,6-diaminohexane, followed by the removal of free polymer via repeated filtering and solvent washing. The coated polyurea content can be controlled to some extent by adjusting the feed ratio of the isocyanato and amino groups. The structure and morphology of the resulting nanocomposites were characterized by FTIR, NMR, Raman, confocal Raman, TEM, EDS, and SEM measurements. The polyurea-coated MWNTs showed interesting self-assembled flat- or flowerlike morphologies in the solid state. The signals corresponding to that of the D and G bands of the carbon nanotubes were strongly attenuated after polyurea was chemically tethered to the MWNT surfaces. Comparative experiments showed that the grafted polymer species and structures have a strong effect on the Raman signals of polymer-functionalized MWNTs
Difficulties with Recovering The Masses of Supermassive Black Holes from Stellar Kinematical Data
We investigate the ability of three-integral, axisymmetric, orbit-based
modeling algorithms to recover the parameters defining the gravitational
potential (M/L ratio and black hole mass Mh) in spheroidal stellar systems
using stellar kinematical data. We show that the potential estimation problem
is generically under-determined when applied to long-slit kinematical data of
the kind used in most black hole mass determinations to date. A range of
parameters (M/L, Mh) can provide equally good fits to the data, making it
impossible to assign best-fit values. We illustrate the indeterminacy using a
variety of data sets derived from realistic models as well as published
observations of the galaxy M32. In the case of M32, our reanalysis demonstrates
that data published prior to 2000 are equally consistent with Mh in the range
1.5x10^6-5x10^6 solar masses, with no preferred value in that range. While the
HST/STIS data for this galaxy may overcome the degeneracy in Mh, HST data for
most galaxies do not resolve the black hole's sphere of influence and in these
galaxies the degree of degeneracy allowed by the data may be substantial. We
investigate the effect on the degeneracy of enforcing smoothness
(regularization) constraints. However we find no indication that the true
potential can be recovered simply by enforcing smoothness. For a given
smoothing level, all solutions in the minimum-chisquare valley exhibit similar
levels of noise. These experiments affirm that the indeterminacy is real and
not an artifact associated with non-smooth solutions. (Abridged)Comment: Accepted for publication in The Astrophysical Journal. Changes
include discussion of regularizatio
Perturbations in the Urinary Exosome in Transplant Rejection
Urine exosomes are small vesicles exocytosed into the urine by all renal epithelial cell types under normal physiologic and disease states. Urine exosomal proteins may mirror disease specific proteome perturbations in kidney injury. Analysis methodologies for the exosomal fraction of the urinary proteome were developed for comparing the urinary exosomal fraction versus unfractionated proteome for biomarker discovery. Urine exosomes were isolated by centrifugal filtration of urine samples collected from kidney transplant patients with and without acute rejection, which were biopsy matched. The proteomes of unfractionated whole urine (Uw) and urine exosomes (Ue) underwent mass spectroscopy-based quantitative proteonomics analysis. The proteome data were analyzed for significant differential protein abundances in acute rejection (AR). A total of 1018 proteins were identified in Uw and 349 proteins in Ue. 279 overlapped between the two urinary compartments and 70 proteins were unique to the Ue compartment. Of 349 exosomal proteins identified from transplant patients,220 had not been previously identified in the normal Ue fraction. 11 Ue proteins, functionally involved in an inflammatory and stress response, were more abundant in urine samples from patients with acute rejection, 3 of which are exclusive to the Ue fraction. Ue AR-specific biomarkers(8) were also detected in Uw, but since they were observed at significantly lower abundances in Uw, they were not significant for AR in Uw. A rapid urinary exosome isolation method and quantitative measurement of enriched Ue proteins was applied. Perturbed proteins in the exosomal compartment of urine collected from kidney transplant patients were specific to inflammatory responses, and were not observed in the Ue fraction from normal healthy subjects. Ue specific protein alterations in renal disease provide potential mechanistic insights and offer a unique panel of sensitive biomarkers for monitoring AR
Sterile neutrinos and supernova nucleosynthesis
A light sterile neutrino species has been introduced to explain
simultaneously the solar and atmospheric neutrino puzzles and the results of
the LSND experiment, while providing for a hot component of dark matter.
Employing this scheme of neutrino masses and mixings, we show how
matter-enhanced active-sterile neutrino transformation followed by
active-active neutrino transformation can solve robustly the neutron deficit
problem encountered by models of r-process nucleosynthesis associated with
neutrino-heated supernova ejecta.Comment: 29 pages, 3 postscript figures, submitted to Phys. Rev.
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