57 research outputs found
Unintended Consequences of Property Tax Relief: New York\u27s STAR Program
New York’s School Tax Relief Program, STAR, provides state-funded property tax relief for homeowners. Like a matching grant, STAR changes the price of public services, thereby altering the incentives of voters and school officials and leading to unintended consequences. Using data for New York State school districts before and after STAR was implemented, we find that STAR resulted in small increases in student performance along with significant decreases in the efficiency with which this performance is delivered and significant increases in school spending and property tax rates. These tax-rate increases magnify existing inequities in New York State’s education finance system
First-Principles Study of Iron Oxide Polytypes: Comparison of GGA+U and Hybrid Functional Method
Iron oxides are materials of wide interest that exhibit diverse electric, magnetic, optical, and catalytic properties; therefore, many studies to gain complete understanding of their polytypic phase boundary have been pursued. However, first-principles investigations of iron oxides using conventional density functional theory (DFT) calculations often yield a gross error due to the strong electron correlation that is poorly described within (semi) local approximations. This limitation often can be overcome using either the Hubbard correction (DFT+U) or a hybrid functional DFT method. Here, we investigate the diverse polytypic phases of iron monoxide (FeO) by comparing DFT+U and the hybrid-functional method (particularly B3PW91). We found that both methods show reasonable agreement in predicting the properties of the experimentally observed phases (B1, B8, iB8, and B2). However, the DFT+U method overestimates the equilibrium volume of B1 phase and predicts the experimentally undiscovered B4 phases to be nearly as stable as the naturally abundant B1 phase. In addition, B3PW91 predicts a local Jahn–Teller distortion pattern of the B1 phase that is more similar than that predicted by DFT+U to the result of a reported low-temperature neutron diffraction experiment. Using B3PW91, which is considered more convincing, we further discuss that there is no clear phase boundary between the monoclinic and rhombohedral B1 phases under compression but that the compression gradually reduces the local anisotropy to yield a rhombohedral-like phase, which agrees with previous experimental diffraction results. We expect that our comprehensive study demonstrates the virtue of using hybrid-functional DFT methods, particularly in exploring various known and unknown polytypic phases of transition-metal oxides
An apparatus for in-vacuum loading of nanoparticles into an optical trap
We describe the design, construction, and operation of an apparatus utilizing
a piezoelectric transducer for in-vacuum loading of nanoparticles into an
optical trap for use in levitated optomechanics experiments. In contrast to
commonly used nebulizer-based trap-loading methods which generate aerosolized
liquid droplets containing nanoparticles, the method produces dry aerosols of
both spherical and high-aspect ratio particles ranging in size by approximately
two orders of mangitude. The device has been shown to generate accelerations of
order , which is sufficient to overcome stiction forces between glass
nanoparticles and a glass substrate for particles as small as nm
diameter. Particles with sizes ranging from nm to m have
been successfully loaded into optical traps at pressures ranging from bar
to mbar. We report the velocity distribution of the particles launched
from the substrate and our results indicate promise for direct loading into
ultra-high-vacuum with sufficient laser feedback cooling. This loading
technique could be useful for the development of compact fieldable sensors
based on optically levitated nanoparticles as well as matter-wave interference
experiments with ultra-cold nano-objects which rely on multiple repeated
free-fall measurements and thus require rapid trap re-loading in high vacuum
conditions.Comment: 9 pages, 10 figure
Cdc42 and Gsk3 modulate the dynamics of radial glial growth, inter-radial glial interactions and polarity in the developing cerebral cortex
Polarized radial glia are crucial to the formation of the cerebral cortex. They serve as neural progenitors and as guides for neuronal placement in the developing cerebral cortex. The maintenance of polarized morphology is essential for radial glial functions, but the extent to which the polarized radial glial scaffold is static or dynamic during corticogenesis remains an open question. The developmental dynamics of radial glial morphology, inter-radial glial interactions during corticogenesis, and the role of the cell polarity complexes in these activities remain undefined. Here, using real-time imaging of cohorts of mouse radial glia cells, we show that the radial glial scaffold, upon which the cortex is constructed, is highly dynamic. Radial glial cells within the scaffold constantly interact with one another. These interactions are mediated by growth cone-like endfeet and filopodia-like protrusions. Polarized expression of the cell polarity regulator Cdc42 in radial glia regulates glial endfeet activities and inter-radial glial interactions. Furthermore, appropriate regulation of Gsk3 activity is required to maintain the overall polarity of the radial glia scaffold. These findings reveal dynamism and interactions among radial glia that appear to be crucial contributors to the formation of the cerebral cortex. Related cell polarity determinants (Cdc42, Gsk3) differentially influence radial glial activities within the evolving radial glia scaffold to coordinate the formation of cerebral cortex
Differential Regulation of Microtubule Severing by APC Underlies Distinct Patterns of Projection Neuron and Interneuron Migration
Coordinated migration of distinct classes of neurons to appropriate positions leads to the formation of functional neuronal circuitry in the cerebral cortex. Two major classes of cortical neurons, interneurons and projection neurons, utilize distinctly different modes (radial vs. tangential) and routes of migration to arrive at their final positions in the cerebral cortex. Here, we show that adenomatous polyposis coli (APC) modulates microtubule (MT) severing in interneurons to facilitate tangential mode of interneuron migration, but not the glial-guided, radial migration of projection neurons. APC regulates the stability and activity of the MT severing protein p60-katanin in interneurons to promote the rapid remodeling of neuronal processes necessary for interneuron migration. These findings reveal how severing and restructuring of MTs facilitate distinct modes of neuronal migration necessary for laminar organization of neurons in the developing cerebral cortex
Genome-wide association and Mendelian randomisation analysis provide insights into the pathogenesis of heart failure
Heart failure (HF) is a leading cause of morbidity and mortality worldwide. A small proportion of HF cases are attributable to monogenic cardiomyopathies and existing genome-wide association studies (GWAS) have yielded only limited insights, leaving the observed heritability of HF largely unexplained. We report results from a GWAS meta-analysis of HF comprising 47,309 cases and 930,014 controls. Twelve independent variants at 11 genomic loci are associated with HF, all of which demonstrate one or more associations with coronary artery disease (CAD), atrial fibrillation, or reduced left ventricular function, suggesting shared genetic aetiology. Functional analysis of non-CAD-associated loci implicate genes involved in cardiac development (MYOZ1, SYNPO2L), protein homoeostasis (BAG3), and cellular senescence (CDKN1A). Mendelian randomisation analysis supports causal roles for several HF risk factors, and demonstrates CAD-independent effects for atrial fibrillation, body mass index, and hypertension. These findings extend our knowledge of the pathways underlying HF and may inform new therapeutic strategies
Democratisation via Elections in an African 'Narco State'? - The Case of Guinea-Bissau
Genome-wide association and Mendelian randomisation analysis provide insights into the pathogenesis of heart failure
Abstract: Heart failure (HF) is a leading cause of morbidity and mortality worldwide. A small proportion of HF cases are attributable to monogenic cardiomyopathies and existing genome-wide association studies (GWAS) have yielded only limited insights, leaving the observed heritability of HF largely unexplained. We report results from a GWAS meta-analysis of HF comprising 47,309 cases and 930,014 controls. Twelve independent variants at 11 genomic loci are associated with HF, all of which demonstrate one or more associations with coronary artery disease (CAD), atrial fibrillation, or reduced left ventricular function, suggesting shared genetic aetiology. Functional analysis of non-CAD-associated loci implicate genes involved in cardiac development (MYOZ1, SYNPO2L), protein homoeostasis (BAG3), and cellular senescence (CDKN1A). Mendelian randomisation analysis supports causal roles for several HF risk factors, and demonstrates CAD-independent effects for atrial fibrillation, body mass index, and hypertension. These findings extend our knowledge of the pathways underlying HF and may inform new therapeutic strategies
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