pinecone/core-2020-05-10-deduplication huggingface dataset:
Challenges and prospects for developing CdS/CdTe substrate solar cells on Mo foils

AbstractITO/ZnO/CdS/CdTe/Mo solar cells have been grown in the substrate configuration by a combination of close-space sublimation and RF sputtering. A peak efficiency of 8.01% was achieved. A two stage CdCl2 annealing process was developed, with the first stage contributing to CdTe doping and the second being linked to CdTe/CdS interdiffusion by secondary ion mass spectrometry analysis. The inclusion of a ZnO layer between CdS and ITO layers improved performance significantly (from η=6% to η=8%) by increasing the shunt resistance, RSH, from 563Ωcm2 to 881Ωcm2. Cross-sectional scanning electron microscopy highlighted the importance of the resistive ZnO layer as numerous pinholes and voids exist in the CdS film. Solar cell performance was also investigated as a function of CdTe thickness, with optimal thicknesses being in the range 3–6μm. All devices were deemed to be limited principally by a non-Ohmic back contact, the Schottky barrier height being determined to be 0.51eV by temperature dependent J–V measurements. Modelling of device performance using SCAPS predicted efficiencies as high as 11.3% may be obtainable upon formation of an Ohmic back-contact. SCAPS modelling also demonstrated that a quasi-Ohmic back-contact may be achievable via inclusion of a highly p-doped (~1018cm−3) buffer layer, between CdTe and Mo, which also has an optimal electron affinity (4.2eV). The evaluation of device processing and the in-depth characterisation presented here provides a number of insights towards the continued improvement of substrate cell performance
Electronic and Structural Properties of N-Type Microcrystalline Silicon Oxide (Mc-Siox:H) Films for Applications in Thin Film Silicon Solar Cells

AbstractThe growth of n-type μc-SiOx:H layers in the thickness range of up to 700nm is investigated. We show that the electrical and structural properties of μc-SiOx:H are thickness dependent but to a weaker extend in comparison with n-type μc-Si:H. μc-SiOx:H layers with low dark conductivity in the order of 10-11 S/cm, measured in the planar direction, can be successfully used as n-layers in amorphous silicon solar cells, resulting in an improved cell performance due to reduced parasitic absorption in the n-type layer. The results suggest anisotropic electrical transport in μc-SiOx:H materials, supported by an observation of elongated crystalline regions in high resolution TEM microscopy
Measurement of the high-mass Drell–Yan differential cross-section in pp collisions at s=7 TeV with the ATLAS detector

AbstractThis Letter reports a measurement of the high-mass Drell–Yan differential cross-section in proton–proton collisions at a centre-of-mass energy of 7 TeV at the LHC. Based on an integrated luminosity of 4.9 fb−1, the differential cross-section in the Z/γ⁎→e+e− channel is measured with the ATLAS detector as a function of the invariant mass, mee, in the range 116<mee<1500 GeV, for a fiducial region in which both the electron and the positron have transverse momentum pT>25 GeV and pseudorapidity |η|<2.5. A comparison is made to various event generators and to the predictions of perturbative QCD calculations at next-to-next-to-leading order
Saturn’s northern auroras as observed using the Hubble Space Telescope

AbstractWe discuss the features of Saturn’s northern FUV auroras as observed during a program of Hubble Space Telescope observations which executed over 2011–2013 and culminated, along with Cassini observations, in a comprehensive multi-spectral observing campaign. Our 2011–2013 observations of the northern aurora are also compared with those from our 2007–2008 observation of the southern aurora. We show that the variety of morphologies of the northern auroras is broadly consistent with the southern, and determine the statistical equatorward and poleward boundary locations. We find that our boundaries are overall consistent with previous observations, although a modest poleward displacement of the poleward boundaries is due to the increased prevalence of poleward auroral patches in the noon and afternoon sectors during this program, likely due to the solar wind interaction. We also show that the northern auroral oval oscillates with the northern planetary period oscillation (PPO) phase in an elongated ellipse with semi-major axis ∼1.6° oriented along the post-dawn/post-dusk direction. We further show that the northern auroras exhibit dawn-side brightenings at zero northern magnetic PPO phase, although there is mixed evidence of auroral emissions fixed in the rotating frame of the northern PPO current system, such that overall the dependence of the auroras on northern magnetic phase is somewhat weak
Uniform existence of the integrated density of states for random Schrödinger operators on metric graphs over Zd

AbstractWe consider ergodic random Schrödinger operators on the metric graph Zd with random potentials and random boundary conditions taking values in a finite set. We show that normalized finite volume eigenvalue counting functions converge to a limit uniformly in the energy variable. This limit, the integrated density of states, can be expressed by a closed Shubin–Pastur type trace formula. It supports the spectrum and its points of discontinuity are characterized by existence of compactly supported eigenfunctions. Among other examples we discuss random magnetic fields and percolation models
The pressure of the SU(N) lattice gauge theory at large N

AbstractWe calculate bulk thermodynamic properties, such as the pressure, energy density, and entropy, in SU(4) and SU(8) lattice gauge theories, for the range of temperatures T⩽2.0Tc and T⩽1.6Tc, respectively. We find that the N=4,8 results are very close to each other, and to what one finds in SU(3), and are far from the asymptotic free-gas value. We conclude that any explanation of the high-T pressure (or entropy) deficit must be such as to survive the N→∞ limit. We give some examples of this constraint in action and comment on what this implies for the relevance of gravity duals
BICEP2, non-Bunch–Davies and entanglement

AbstractBICEP2 result on the tensor to scalar ratio r indicates a blue tilt in the primordial gravitational wave spectrum. This blue tilt and the observed large value r=0.2 are difficult to accommodate within the single field inflationary scenarios under standard conditions. Non-Bunch–Davies vacuum states have been proposed as a possibility. Such vacua are known to lead to pathologies. In this note we point out that it is known that these states ought to be interpreted as excited/squeezed states built over the standard Bunch–Davies vacuum in order to avoid pathological issues. We discuss the associated entanglement properties due to de Sitter horizon, and how such an approach may be more natural in the context of inflation. In particular, we suggest to employ entanglement considerations in de Sitter background to study the nature and intrinsic properties of modified initial states
Functional integral representations of the Pauli–Fierz model with spin 1/2

AbstractA Feynman–Kac-type formula for a Lévy and an infinite-dimensional Gaussian random process associated with a quantized radiation field is derived. In particular, a functional integral representation of e−tHPF generated by the Pauli–Fierz Hamiltonian with spin 1/2 in non-relativistic quantum electrodynamics is constructed. When no external potential is applied HPF turns translation-invariant and it is decomposed as a direct integral HPF=∫R3⊕HPF(P)dP. The functional integral representation of e−tHPF(P) is also given. Although all these Hamiltonians include spin, nevertheless the kernels obtained for the path measures are scalar rather than matrix expressions. As an application of the functional integral representations energy comparison inequalities are derived
Theoretical and Experimental SHG Angular Intensity Patterns from Healthy and Proteolysed Muscles

AbstractSHG angular intensity pattern (SHG-AIP) of healthy and proteolysed muscle tissues are simulated and imaged here for the first time to our knowledge. The role of the spatial distribution of second-order nonlinear emitters on SHG-AIP is highlighted. SHG-AIP with two symmetrical spots is found to be a signature of healthy muscle whereas SHG-AIP with one centered spot in pathological mdx muscle is found to be a signature of myofibrillar disorder. We also show that SHG-AIP provides information on the three-dimensional structural organization of myofibrils in physiological and proteolysed muscle. Our results open an avenue for future studies aimed at unraveling more complex physiological and pathological fibrillar tissues organization
Synaptic Integration of Adult-Born Hippocampal Neurons Is Locally Controlled by Astrocytes

SummaryAdult neurogenesis is regulated by the neurogenic niche, through mechanisms that remain poorly defined. Here, we investigated whether niche-constituting astrocytes influence the maturation of adult-born hippocampal neurons using two independent transgenic approaches to block vesicular release from astrocytes. In these models, adult-born neurons but not mature neurons showed reduced glutamatergic synaptic input and dendritic spine density that was accompanied with lower functional integration and cell survival. By taking advantage of the mosaic expression of transgenes in astrocytes, we found that spine density was reduced exclusively in segments intersecting blocked astrocytes, revealing an extrinsic, local control of spine formation. Defects in NMDA receptor (NMDAR)-mediated synaptic transmission and dendrite maturation were partially restored by exogenous D-serine, whose extracellular level was decreased in transgenic models. Together, these results reveal a critical role for adult astrocytes in local dendritic spine maturation, which is necessary for the NMDAR-dependent functional integration of newborn neurons.Video Abstrac
Search for dark matter produced with an energetic jet or a hadronically
  decaying W or Z boson at sqrt(s) = 13 TeV

A search for dark matter particles is performed using events with large
missing transverse momentum, at least one energetic jet, and no leptons, in
proton-proton collisions at sqrt(s) = 13 TeV collected with the CMS detector at
the LHC. The data sample corresponds to an integrated luminosity of 12.9
inverse femtobarns. The search includes events with jets from the hadronic
decays of a W or Z boson. The data are found to be in agreement with the
predicted background contributions from standard model processes. The results
are presented in terms of simplified models in which dark matter particles are
produced through interactions involving a vector, axial-vector, scalar, or
pseudoscalar mediator. Vector and axial-vector mediator particles with masses
up to 1.95 TeV, and scalar and pseudoscalar mediator particles with masses up
to 100 and 430 GeV respectively, are excluded at 95% confidence level. The
results are also interpreted in terms of the invisible decays of the Higgs
boson, yielding an observed (expected) 95% confidence level upper limit of 0.44
(0.56) on the corresponding branching fraction. The results of this search
provide the strongest constraints on the dark matter pair production cross
section through vector and axial-vector mediators at a particle collider. When
compared to the direct detection experiments, the limits obtained from this
search provide stronger constraints for dark matter masses less than 5, 9, and
550 GeV, assuming vector, scalar, and axial-vector mediators, respectively. The
search yields stronger constraints for dark matter masses less than 200 GeV,
assuming a pseudoscalar mediator, when compared to the indirect detection
results from Fermi-LAT.Comment: Replaced with the published version. Added the journal reference and
  DOI. All the figures and tables can be found at
  http://cms-results.web.cern.ch/cms-results/public-results/publications/EXO-16-03
Implementing NLO DGLAP evolution in Parton Showers

We present a parton shower which implements the DGLAP evolution of parton
densities and fragmentation functions at next-to-leading order precision up to
effects stemming from local four-momentum conservation. The Monte-Carlo
simulation is based on including next-to-leading order collinear splitting
functions in an existing parton shower and combining their soft enhanced
contributions with the corresponding terms at leading order. Soft double
counting is avoided by matching to the soft eikonal. Example results from two
independent realizations of the algorithm, implemented in the two event
generation frameworks Pythia and Sherpa, illustrate the improved precision of
the new formalism.Comment: 11 pages, 4 figure
Planck intermediate results: XLII. Large-scale Galactic magnetic fields

Recent models for the large-scale Galactic magnetic fields in the literature have been largely constrained by synchrotron emission and Faraday rotation measures. We use three different but representative models to compare their predicted polarized synchrotron and dust emission with that measured by the Planck satellite. We first update these models to match the Planck synchrotron products using a common model for the cosmic-ray leptons. We discuss the impact on this analysis of the ongoing problems of component separation in the Planck microwave bands and of the uncertain cosmic-ray spectrum. In particular, the inferred degree of ordering in the magnetic fields is sensitive to these systematic uncertainties, and we further show the importance of considering the expected variations in the observables in addition to their mean morphology. We then compare the resulting simulated emission to the observed dust polarization and find that the dust predictions do not match the morphology in the Planck data but underpredict the dust polarization away from the plane. We modify one of the models to roughly match both observables at high latitudes by increasing the field ordering in the thin disc near the observer. Though this specific analysis is dependent on the component separation issues, we present the improved model as a proof of concept for how these studies can be advanced in future using complementary information from ongoing and planned observational projects
Metabolic re-wiring of isogenic breast epithelial cell lines following epithelial to mesenchymal transition.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked FilesEpithelial to mesenchymal transition (EMT) has implications in tumor progression and metastasis. Metabolic alterations have been described in cancer development but studies focused on the metabolic re-wiring that takes place during EMT are still limited. We performed metabolomics profiling of a breast epithelial cell line and its EMT derived mesenchymal phenotype to create genome-scale metabolic models descriptive of both cell lines. Glycolysis and OXPHOS were higher in the epithelial phenotype while amino acid anaplerosis and fatty acid oxidation fueled the mesenchymal phenotype. Through comparative bioinformatics analysis, PPAR-γ1, PPAR- γ2 and AP-1 were found to be the most influential transcription factors associated with metabolic re-wiring. In silico gene essentiality analysis predicts that the LAT1 neutral amino acid transporter is essential for mesenchymal cell survival. Our results define metabolic traits that distinguish an EMT derived mesenchymal cell line from its epithelial progenitor and may have implications in cancer progression and metastasis. Furthermore, the tools presented here can aid in identifying critical metabolic nodes that may serve as therapeutic targets aiming to prevent EMT and inhibit metastatic dissemination
Simulation of junctionless Si nanowire transistors with 3 nm gate length

Inspired by recent experimental realizations and theoretical simulations of thin silicon nanowire-based devices, we perform proof-of-concept simulations of junctionless gated Si nanowire transistors. Based on first-principles, our primary predictions are that Si-based transistors are physically possible without major changes in design philosophy at scales of similar to 1 nm wire diameter and similar to 3 nm gate length, and that the junctionless transistor avoids potentially serious difficulties affecting junctioned channels at these length scales. We also present investigations into atomic-level design factors such as dopant positioning and concentration. (C) 2010 American Institute of Physics. (doi:10.1063/1.3478012
Search for third-generation scalar leptoquarks and heavy right-handed neutrinos in final states with two tau leptons and two jets in proton-proton collisions at sqrt(s) = 13 TeV

A search is performed for third-generation scalar leptoquarks and heavy right-handed neutrinos in events containing one electron or muon, one hadronically decaying tau lepton, and at least two jets, using a root s = 13 TeV pp collision data sample corresponding to an integrated luminosity of 12: 9 fb(-1) collected with the CMS detector at the LHC in 2016. The number of observed events is found to be in agreement with the standard model prediction. A limit is set at 95% confidence level on the product of the leptoquark pair production cross section and beta(2), where beta is the branching fraction of leptoquark decay to a tau lepton and a bottom quark. Assuming beta = 1, third-generation leptoquarks with masses below 850 GeV are excluded at 95% confidence level. An additional search based on the same event topology involves heavy right-handed neutrinos, N-R, and right-handed W bosons, W-R, arising in a left-right symmetric extension of the standard model. In this search, W-R bosons are assumed to decay to a tau lepton and N-R followed by the decay of the N-R to a tau lepton and an off-shell W-R boson. Assuming the mass of the right-handed neutrino to be half of the mass of the right-handed W boson, W-R boson masses below 2.9 TeV are excluded at 95% confidence level. These results improve on the limits from previous searches for third-generation leptoquarks and heavy right-handed neutrinos with tau leptons in the final state
The critical window for the classical Ramsey-Tur\'an problem

The first application of Szemer\'edi's powerful regularity method was the
following celebrated Ramsey-Tur\'an result proved by Szemer\'edi in 1972: any
K_4-free graph on N vertices with independence number o(N) has at most (1/8 +
o(1)) N^2 edges. Four years later, Bollob\'as and Erd\H{o}s gave a surprising
geometric construction, utilizing the isoperimetric inequality for the high
dimensional sphere, of a K_4-free graph on N vertices with independence number
o(N) and (1/8 - o(1)) N^2 edges. Starting with Bollob\'as and Erd\H{o}s in
1976, several problems have been asked on estimating the minimum possible
independence number in the critical window, when the number of edges is about
N^2 / 8. These problems have received considerable attention and remained one
of the main open problems in this area. In this paper, we give nearly
best-possible bounds, solving the various open problems concerning this
critical window.Comment: 34 page
Concentration Dependent Interdiffusion in InGaAs/GaAs as Evidenced by High Resolution X-ray Diffraction and Photoluminescence Spectroscopy

<p>A high resolution x-ray diffraction (HRXRD) and photoluminescence study of a 10 nm InGaAs/GaAs quantum well structure repeatedly diffused under thermally accurate and timed annealing conditions demonstrates that the Fickian model with a constant coefficient of diffusion is inadequate and that the distribution of compositions of the diffused well cannot be fitted with error functions. A simple model, with the well retaining its square shape and homogeneity while dissolving the barriers when annealed, is successful in modelling both the HRXRD and photoluminescence data.</p
Tourism Demand Modelling and Forecasting

<p>This paper reviews the published studies on tourism demand modelling and forecasting since 2000. One of the key findings of this review is that the methods used in analysing and forecasting the demand for tourism have been more diverse than those identified by other review articles. In addition to the most popular time series and econometric models, a number of new techniques have emerged in the literature. However, as far as the forecasting accuracy is concerned, the study shows that there is no single model that consistently outperforms other models in all situations. Furthermore, this study identifies some new research directions, which include improving the forecasting accuracy through forecast combination; integrating both qualitative and quantitative forecasting approaches, tourism cycles and seasonality analysis, events’ impact assessment and risk forecasting.</p
An evaluation of the RAPID assessment-based process improvement method for small firms

[Abstract]: With increasing interest by the software development community in software process improvement (SPI), it is vital that SPI programs are evaluated and the reports of lessons learned disseminated. This paper presents an evaluation of a program in which low-rigour, one-day SPI assessments were offered at no cost to 22 small Australian software development firms. The assessment model was based on ISO/IEC 15504 (SPICE). About twelve months after the assessment, the firms were contacted to arrange a follow-up meeting to determine the extent to which they had implemented the recommendations from the assessment.\ud
Comparison of the process capability levels at the time of assessment and the follow-up meetings revealed that the process improvement program was effective in improving the process capability of many of these small software development firms. Analysis of the assessment and follow-up reports explored important issues relating to SPI: elapsed time from assessment to follow-up meeting, the need for mentoring, the readiness of firms for SPI, the role of the owner/manager, the advice provided by the\ud
assessors, and the need to record costs and benefits. Based on a meta-analysis of the program and its outcomes, advice and recommendations are provided to small firms and assessors. As well as providing validation of the assessment model and method, the outcomes from this research have the potential to better equip practitioners and consultants to undertake software process improvement, hence increasing the success of small software development firms in domestic and global markets
Image-based visual servoing for the super-orbital re-entry of Hayabusa spacecraft

This paper presents an image-based visual servoing system that was used to track the atmospheric Earth re-entry of Hayabusa. The primary aim of this ground based tracking platform was to record the emission spectrum radiating from the superheated gas of the shock layer and the surface of the heat shield during reentry. To the author's knowledge, this is the first time that a visual servoing system has successfully tracked a super-orbital re-entry of a spacecraft and recorded its spectral signature. Furthermore, we improve the system by including a simplified dynamic model for feed-forward control and demonstrate improved tracking performance on the International Space Station (ISS). We present comparisons between simulation and experimental results on different target trajectories including tracking results from Hayabusa and ISS. The required performance for tracking both spacecraft is demanding when combined with a narrow field of view (FOV). We also briefly discuss the preliminary results obtained from the spectroscopy of the Hayabusa's heat shield during re-entry.