16,499 research outputs found
A Bijection between Atomic Partitions and Unsplitable Partitions
In the study of the algebra of symmetric functions in
noncommutative variables, Bergeron and Zabrocki found a free generating set
consisting of power sum symmetric functions indexed by atomic partitions. On
the other hand, Bergeron, Reutenauer, Rosas, and Zabrocki studied another free
generating set of consisting of monomial symmetric functions
indexed by unsplitable partitions. Can and Sagan raised the question of finding
a bijection between atomic partitions and unsplitable partitions. In this
paper, we provide such a bijection.Comment: 6 page
Effect Of AlN Spacer In The Layer Structure On High Rf Performance GaN-Based HEMTs On Low Resistivity Silicon At K-Band Application
AlGaN/GaN High Electron Mobility Transistors (HEMTs) grown on Si substrate are emerging as an attractive devices for many RF applications. This is due to lower circuits realization cost and multifunction chips integration. In this study we investigate the effect of AlN spacer between AlGaN and GaN of a sub-micron gate (0.3 μm) AlGaN/GaN and AlGaN/AlN/GaN HEMTs on a Low Resistivity LR Si substrates on RF performance. We have observed an enhancement in RF performance fT and fMAX in the HEMT with of AlN spacer; (fT) was increased from 47 GHz to 55 GHz and (fMAX) was increased from 79 GHz to 121 GHz. This enhancement in performance is mainly due to the increase in the mobility in the channel and confinement of the carriers reducing Cgs, and delay τ under the gate. We believe this is the first RF study of this type as previous studies were based on the effects of the DC characteristic of the devices [1]
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Neoadjuvant sipuleucel-T induces both Th1 activation and immune regulation in localized prostate cancer.
Sipuleucel-T is the only FDA-approved immunotherapy for metastatic castration-resistant prostate cancer. The mechanism by which this treatment improves survival is not fully understood. We have previously shown that this treatment can induce the recruitment of CD4 and CD8 T cells to the tumor microenvironment. In this study, we examined the functional state of these T cells through gene expression profiling. We found that the magnitude of T cell signatures correlated with the frequency of T cells as measured by immunohistochemistry. Sipuleucel-T treatment was associated with increased expression of Th1-associated genes, but not Th2-, Th17 - or Treg-associated genes. Post-treatment tumor tissues with high CD8+T cell infiltration was associated with high levels of CXCL10 expression. On in situ hybridization, CXCL10+ cells colocalized with CD8+T cells in post-treatment prostatectomy tumor tissue. Neoadjuvant sipuleucel-T was also associated with upregulation of immune inhibitory checkpoints, including CTLA4 and TIGIT, and downregulation of the immune activation marker, dipeptidylpeptidase, DPP4. Treatment-associated declines in serum PSA were correlated with induction of Th1 response. In contrast, rises in serum PSA while on treatment were associated with the induction of multiple immune checkpoints, including CTLA4, CEACAM6 and TIGIT. This could represent adaptive immune resistance mechanisms induced by treatment. Taken together, neoadjuvant sipuleucel-T can induce both a Th1 response and negative immune regulation in the prostate cancer microenvironment
Canonical variate analysis, probability approach and support vector regression for fault identification and failure time prediction
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI linkReciprocating compressors are widely used in oil and gas industry for gas transport, lift and injection. Critical compressors that compress flammable gases and operate at high speeds are high priority equipment on maintenance improvement lists. Identifying the root causes of faults and estimating remaining usable time for reciprocating compressors could potentially reduce downtime and maintenance costs, and improve safety and availability. In this study, Canonical Variate Analysis (CVA), Cox Proportional Hazard (CPHM) and Support Vector Regression (SVR) models are employed to identify fault related variables and predict remaining usable time based on sensory data acquired from an operational industrial reciprocating compressor. 2-D contribution plots for CVA-based residual and state spaces were developed to identify variables that are closely related to compressor faults. Furthermore, a SVR model was used as a prognostic tool following training with failure rate vectors obtained from the CPHM and health indicators obtained from the CVA model. The trained SVR model was utilized to estimate the failure degradation rate and remaining useful life of the compressor. The results indicate that the proposed method can be effectively used in real industrial processes to perform fault diagnosis and prognosis
Toward a Broadband Astro-comb: Effects of Nonlinear Spectral Broadening in Optical Fibers
We propose and analyze a new approach to generate a broadband astro-comb by
spectral broadening of a narrowband astro-comb inside a highly nonlinear
optical fiber. Numerical modeling shows that cascaded four-wave-mixing
dramatically degrades the input comb's side-mode suppression and causes
side-mode amplitude asymmetry. These two detrimental effects can systematically
shift the center-of-gravity of astro-comb spectral lines as measured by an
astrophysical spectrograph with resolution \approx100,000; and thus lead to
wavelength calibration inaccuracy and instability. Our simulations indicate
that this performance penalty, as a result of nonlinear spectral broadening,
can be compensated by using a filtering cavity configured for double-pass. As
an explicit example, we present a design based on an Yb-fiber source comb (with
1 GHz repetition rate) that is filtered by double-passing through a low finesse
cavity (finesse = 208), and subsequent spectrally broadened in a 2-cm,
SF6-glass photonic crystal fiber. Spanning more than 300 nm with 16 GHz line
spacing, the resulting astro-comb is predicted to provide 1 cm/s (~10 kHz)
radial velocity calibration accuracy for an astrophysical spectrograph. Such
extreme performance will be necessary for the search for and characterization
of Earth-like extra-solar planets, and in direct measurements of the change of
the rate of cosmological expansion.Comment: 9 pages, 6 figure
Conversion of a metastable superhydrophobic surface to an ultraphobic surface
Superhydrophobic surfaces in Wenzel and metastable wetting state were prepared and the conversion of such surfaces to ultraphobic surfaces was reported by the application of a fine-scale roughness. Silicon nitride substrates with hexagonally arranged pillars were prepared by micromachining. The two-scale roughness was achieved by coating these substrates with 60 nm silica nanoparticles. The surface was made hydrophobic by silanization with octadecytrichlorosilane (OTS). Wettability studies of the silicon nitride flat surface, silicon nitride pillars, and the surfaces with two-scale roughness showed that a two-scale roughness can effectively improve the hydrophobicity of surfaces with a higher apparent contact angle and reduced contact angle hysteresis when the original rough surface was in a metastable or Wenzel state. This study shows the pathway of converting a metastable hydrophobic surface to an ultraphobic surface by the introduction of a fine-scale roughness, which adds to the literature a new aspect of fine-scale roughness effect
An inventory of glacier changes between 1973 and 2011 for the Geladandong Mountain area, China.
This is the publisher's version, also available electronically from http://www.the-cryosphere-discuss.net/7/507/2013/tcd-7-507-2013.htmlThe snow and ice of the Geladangong Mountain area supply the headwaters of the Yangtze River, and long-term changes to glaciers and ice masses in this region due to a warming climate are of great concern. An inventory of glacier boundaries and changes over decades for the Geladandong Mountain area in China has been conducted using remote sensing imagery from Landsat (MSS, TM, ETM+), CERBES CCD, and GIS techniques. Variations in glacier extent has been measured using a~series of digital images since 1973, including Landsat MSS in 1973, Landsat TM in 1992, Landsat ETM+ in 2004, and CBERS CCD in 2011. All Landsat data are snow-free outside the glacier boundaries, allowing an unsupervised classification method to be used to extract glacier area. For the CBERS CCD data, some areas were covered by clouds and snow, requiring an initial unsupervised classification method to divide glacier, clouds and snow from other land types, followed by a supervised visual interpretation to extract glacier area. The results show a decrease in glacier ice cover in the study area during the past 38 yr. From 1973 to 2011, glacier area decreased from 107 105 hectares to 94 220 hectares, or a change of −12%. The speed at which ice cover is being lost has been decreasing during the past 38 yr. The rate of glacier area loss was 0.47% yr−1 from 1973–1992, 0.19% yr−1 from 1992–2004, and 0.14% yr−1 from 2004–2011. While most of the glaciers are shrinking, some are expanding. For the 1973 to 2004 period, retreating glaciers exposed 14 447 hectares of land, and advancing glaciers spread over 2682 hectares that were not covered by ice in 1973. The net glacier area decrease is 11 765 hectares from 1973–2004. For the 1973 to 2011 period, glaciers expanded over 3791 hectares, and retreated from 16 504 hectares
Factors impacting on cleaner production: Case studies of Chinese pharmaceutical manufacturers in Tianjin, China
The literature contains a number of studies exploring factors impacting on cleaner production, but few studying these factors simultaneously. This study has identified these factors in the literature and represented their relationships with cleaner production in a conceptual framework. The key factors included in this framework are ISO14001 certification, eco-innovation of product and process, industrial and government regulations, and environmentally-friendly culture. Nine major Chinese pharmaceutical companies in Tianjin, China, have been used as case study companies to explore the impact of these key factors on cleaner production. The analysis reveals that companies that have ISO14001 certification are likely to be one step ahead; however ISO14001 certification is not the only factor leading these manufacturing companies to be active in cleaner production. It is green process innovation rather than product innovation that directly impacts on cleaner production. The environmentally-friendly culture significantly influences the promotion of cleaner production. It is concluded that the industry needs to promote process-oriented innovations and build environmentally-friendly culture in order to be more active in cleaner production in the long-run. This paper provides case-based insight for cleaner production and environmental sustainability researchers and the strategic direction for manufacturing companies to achieve cleaner production and environmental sustainability
The Use of On-line Capillary Electrophoresis/Electrospray Ionization with Detection via an Ion Trap Storage/Reflectron Time-of-flight Mass Spectrometer for Rapid Mutation-site Analysis of Hemoglobin Variants
Generalization of the density-matrix method to a non-orthogonal basis
We present a generalization of the Li, Nunes and Vanderbilt density-matrix
method to the case of a non-orthogonal set of basis functions. A representation
of the real-space density matrix is chosen in such a way that only the overlap
matrix, and not its inverse, appears in the energy functional. The generalized
energy functional is shown to be variational with respect to the elements of
the density matrix, which typically remains well localized.Comment: 11 pages + 2 postcript figures at the end (search for -cut here
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