1,006 research outputs found
Seiberg-Witten Curve for the E-String Theory
We construct the Seiberg-Witten curve for the E-string theory in
six-dimensions. The curve is expressed in terms of affine E_8 characters up to
level 6 and is determined by using the mirror-type transformation so that it
reproduces the number of holomorphic curves in the Calabi-Yau manifold and the
amplitudes of N=4 U(n) Yang-Mills theory on 1/2 K3. We also show that our curve
flows to known five- and four-dimensional Seiberg-Witten curves in suitable
limits.Comment: 18 pages, 1 figure; appendix C adde
Observation of the Ettingshausen effect in quantum Hall systems
Evidence of the Ettingshausen effect in the breakdown regime of the integer
quantum Hall effect has been observed in a GaAs/AlGaAs two-dimensional electron
system. Resistance of micro Hall bars attached to both edges of a current
channel shows remarkable asymmetric behaviors which indicate an electron
temperature difference between the edges. The sign of the difference depends on
the direction of the electric current and the polarity of the magnetic field.
The results are consistent with the recent theory of Akera.Comment: 4 pages, 6 figures, submitted to Phys. Rev.
Automatic Generation of Test Cases Using Document Analysis Techniques
In software maintenance, software testing consumes 55% of the total software maintenance work. The problem is how to reduce the software testing work while still insuring high quality software.nbsp Some solutions involve software execution automation tools, outsourcing the testing tasks at lower labor rates. Such solutions still depend upon individual skills in generation of the test cases. In contrast, we focused on generation of test cases rather than the skills and developed a method for the automatic generation of test cases by using our natural language document analysis techniques which use text parsers for extracting and complementing parameter values from documents. We applied the method to Internet banking system maintenance projects and insurance system maintenance projects.nbsp In this paper, we discuss our method and techniques for automatic generation of test cases and their use in these industry case studies.nbsp Our document analysis tool helped automatically generate 95% of the required test cases from the design documents. The work of creating test cases was reduced by 48% in our case studies
Similarity between compact extremely red objects discovered with JWST in cosmic dawn and blue-excess dust-obscured galaxies known in cosmic noon
Spatially compact objects with extremely red color in the rest-frame optical
to near-infrared (0.4--3.0 ) and blue color in the rest-frame
ultraviolet (UV; 0.2--0.4 ) have been discovered at
using the James Webb Space Telescope (JWST). These extremely red objects
(JWST-EROs) exhibit spectral energy distributions (SEDs) that are difficult to
explain using a single component of either star-forming galaxies or quasars,
leading to two-component models in which the blue UV and extremely red optical
are explained using less-dusty and dusty spectra of galaxies or quasars,
respectively. Here, we report the remarkable similarity in SEDs between
JWST-EROs and blue-excess dust-obscured galaxies (BluDOGs) identified at . BluDOGs are a population of active galactic nuclei (AGNs) with blackhole
masses of M, which are one order of magnitude larger
than those in some JWST-EROs. The Eddington accretion rates of BluDOGs are one
or higher, whereas those of JWST-EROs are in the range of 0.1--1. Therefore,
JWST-EROs are less massive, less active, and more common counterparts in
higher- of BluDOGs in cosmic noon. Conversely, JWST-EROs have a
significantly higher fraction of those with blue-excess than DOGs. We present
the average UV spectra of BluDOGs as a comparison to JWST-EROs and discuss a
coherent evolutionary scenario for dusty AGN populations.Comment: 10 pages, 5 figures, submitted to ApJ
Wide-Supply-Range All-Digital Leakage Variation Sensor for On-Chip Process and Temperature Monitoring
Variation in process, voltage and temperature is a major obstacle in achieving energy-efficient operation of LSI. This paper proposes an all-digital on-chip circuit to monitor leakage current variations of both of the nMOSFET and pMOSFET independently. As leakage current is highly sensitive to threshold voltage and temperature, the circuit is suitable for tracking process and temperature variation. The circuit uses reconfigurable inhomogeneity to obtain statistical properties from a single monitor instance. A compact reconfigurable inverter topology is proposed to implement the monitor circuit. The compact and digital nature of the inverter enables cell-based design, which will reduce design costs. Measurement results from a 65 nm test chip show the validity of the proposed circuit. For a 124 sample size for both of the nMOSFET and pMOSFET, the monitor area is 4500 μm2 and active power consumption is 76 nW at 0.8 V operation. The proposed technique enables area-efficient and low-cost implementation thus can be used in product chips for applications such as dynamic energy and thermal management, testing and post-silicon tuning
Decay of Superconducting and Magnetic Correlations in One- and Two-Dimensional Hubbard Models
In a general class of one and two dimensional Hubbard models, we prove upper
bounds for the two-point correlation functions at finite temperatures for
electrons, for electron pairs, and for spins. The upper bounds decay
exponentially in one dimension, and with power laws in two dimensions. The
bounds rule out the possibility of the corresponding condensation of
superconducting electron pairs, and of the corresponding magnetic ordering. Our
method is general enough to cover other models such as the t-J model.Comment: LaTeX, 8 pages, no figures. A reference appeared after the
publication is adde
Anti-correlation between the mass of a supermassive black hole and the mass accretion rate in type I ultraluminous infrared galaxies and nearby QSOs
We discovered a significant anti-correlation between the mass of a
supermassive black hole (SMBH), , and the luminosity ratio of
infrared to active galactic nuclei (AGN) Eddington luminosity, , over four orders of magnitude for ultraluminous infrared
galaxies with type I Seyfert nuclei (type I ULIRGs) and nearby QSOs. This
anti-correlation ( vs. ) can be interpreted
as the anti-correlation between the mass of a SMBH and the rate of mass
accretion onto a SMBH normalized by the AGN Eddington rate, . In other words, the mass accretion rate is not proportional to that of the central BH mass. Thus, this
anti-correlation indicates that BH growth is determined by the external mass
supply process, and not the AGN Eddington-limited mechanism. Moreover, we found
an interesting tendency for type I ULIRGs to favor a super-Eddington accretion
flow, whereas QSOs tended to show a sub-Eddington flow. On the basis of our
findings, we suggest that a central SMBH grows by changing its mass accretion
rate from super-Eddington to sub-Eddington. According to a coevolution scenario
of ULIRGs and QSOs based on the radiation drag process, it has been predicted
that a self-gravitating massive torus, whose mass is larger than a central BH,
exists in the early phase of BH growth (type I ULIRG phase) but not in the
final phase of BH growth (QSO phase). At the same time, if one considers the
mass accretion rate onto a central SMBH via a turbulent viscosity, the
anti-correlation ( vs. ) is well explained
by the positive correlation between the mass accretion rate
and the mass ratio of a massive torus to a SMBH.Comment: 29 pages, 4 figures, accepted for publication in Ap
Diversity of Azoles Resistant Aspergillus Species Isolated from Experience and Naïve Soils in Nairobi County and Naivasha Sub-County Kenya
New triazole antifungals voriconazole, itraconazole and posaconazole are recommended for prophylaxis and treatment of both invasive and chronic fungal infections such as aspergillosis and aspergilloma. Emergence of azole-resistant among A. fumigatus isolates have been reported in other countries including Tanzania ascribed to either previous antifungal treatment, prophylaxis or triazoles use in agriculture. The use of azole based fungicides in the robust horticulture in Kenya is a significant risk factor for antifungal resistance. The study proposes to analyze environmental isolates of Aspergillus fumigatus, Aspergillus flavus and Aspergillus niger for the presence of resistance against the triazoles antifungals. Fungicide naïve soils were obtained from uncultivated virgin fields while fungicide experience soils were collected from flower, agricultural and horticultural fields and greenhouses within Naivasha sub-county and Nairobi County. The fungal isolates were subjected to antifungal susceptibility to triazoles using broth micro dilution method. A total of 492 samples were analyzed in Nairobi, 52 isolates were identified and they resistance were as follow: A. fumigatus (32%), A. niger (26.09%), A. flavus (33.33%) and A .terreus (0%) and in Naivasha 44 isolates were isolated out of which 25 were A. fumigatus and its resistance was at 36%. Data were analyses using student T test and showed they no different between resistant and susceptible isolates from the two location. Data generated will serve to inform on the current status of triazoles resistance pattern and to raise concern emerging antifungal resistance in clinical practice
Effects of a burst of formation of first-generation stars on the evolution of galaxies
First-generation (Population III) stars in the universe play an important
role inearly enrichment of heavy elements in galaxies and intergalactic medium
and thus affect the history of galaxies. The physical and chemical properties
of primordial gas clouds are significantly different from those of present-day
gas clouds observed in the nearby universe because the primordial gas clouds do
not contain any heavy elements which are important coolants in the gas.
Previous theoretical considerations have suggested that typical masses of the
first-generation stars are between several and
although it has been argued that the formation of very massive stars (e.g., ) is also likely. If stars with several are most popular
ones at the epoch of galaxy formation, most stars will evolve to hot (e.g.,
K), luminous () stars with gaseous and dusty
envelope prior to going to die as white dwarf stars. Although the duration of
this phase is short (e.g., yr), such evolved stars could contribute
both to the ionization of gas in galaxies and to the production of a lot of
dust grains if the formation of intermediate-mass stars is highly enhanced. We
compare gaseous emission-line properties of such nebulae with some interesting
high-redshift galaxies such asIRAS F10214+4724 and powerful radio galaxies.Comment: 25 pages, 7 figures, ApJ, in pres
Topology dependent quantities at the Anderson transition
The boundary condition dependence of the critical behavior for the three
dimensional Anderson transition is investigated. A strong dependence of the
scaling function and the critical conductance distribution on the boundary
conditions is found, while the critical disorder and critical exponent are
found to be independent of the boundary conditions
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