pinecone/core-2020-05-10-deduplication huggingface dataset:
Voltage limitation analysis in strain-balanced InAs/GaAsN quantum dot solar cells applied to the intermediate band concept

Several attempts have been carried out to manufacture intermediate band solar cells (IBSC) by means of quantum dot (QD) superlattices. This novel photovoltaic concept allows the collection of a wider range of the sunlight spectrum in order to provide higher cell photocurrent while maintaining the open-circuit voltage (VOC) of the cell. In this work, we analyze InAs/GaAsN QD-IBSCs. In these cells, the dilute nitrogen in the barrier plays an important role for the strain-balance (SB) of the QD layer region that would otherwise create dislocations under the effect of the accumulated strain. The introduction of GaAsN SB layers allows increasing the light absorption in the QD region by multi-stacking more than 100 QD layers. The photo-generated current density (JL) versus VOC was measured under varied concentrated light intensity and temperature. We found that the VOC of the cell at 20 K is limited by the bandgap of the GaAsN barriers, which has important consequences regarding IBSC bandgap engineering that are also discussed in this work
Improvement of energy-momentum tensor and non-Gaussianities in holographic cosmology

In holographic models of cosmology based on the (A)dS/CFT correspondence, conformal symmetry is implicit in the dual description of the Universe. Generically, however, one cannot expect the (broken) conformal invariance in the cosmic fluctuations as only the scale invariance is manifest in experiments. Also, in order for the prediction of the holographic models to make sense, the conformal symmetry needs to be broken as the scalar mode of the metric fluctuations becomes pure gauge in the conformal limit. We discuss the improvement ambiguity of the energy-momentum tensor in this context and construct a holographic model of the Universe that preserves the scale invariance but not necessarily the full conformal invariance. Our sample computation using a weakly coupled dual field theory shows that the orthogonal type of non-Gaussianity is present over and above the equilateral type. The improvement ambiguity corresponds to the choice of the energy momentum tensor that will couple to our particle physics sector after inflation. Our results show that the holographic prediction of the cosmological parameters crucially depends on such a choice
Connecting the ground state mean square radius to the dipole excitation

PTHWe study relationships between the dipole excitation and the ground state ms radius of a two-body system in the case of local potentials. We recall the inequality obtained long ago by Bertlmann and Martin, and discuss correction factors transforming the inequality in an approximate expression. Connecting the correction factor to the contribution of the lowest dipole state to the sum rule, we get a lower bound to the ms radius. Inverting the relationships yields a bound for the square of the dipole transition matrix element, and thus a bound to the lowest dipole state transition rate
Fluctuation theorems for harmonic oscillators

We study experimentally the thermal fluctuations of energy input and dissipation in a harmonic oscillator driven out of equilibrium, and search for Fluctuation Relations. We study transient evolution from the equilibrium state, together with non equilibrium steady states. Fluctuations Relations are obtained experimentally for both the work and the heat, for the stationary and transient evolutions. A Stationary State Fluctuation Theorem is verified for the two time prescriptions of the torque. But a Transient Fluctuation Theorem is satisfied for the work given to the system but not for the heat dissipated by the system in the case of linear forcing. Experimental observations on the statistical and dynamical properties of the fluctuation of the angle, we derive analytical expressions for the probability density function of the work and the heat. We obtain for the first time an analytic expression of the probability density function of the heat. Agreement between experiments and our modeling is excellent
Front blocking and propagation in cylinders with varying cross section

International audienceIn this paper we consider a bistable reaction-diffusion equation in unbounded domains and we investigate the existence of propagation phenomena, possibly partial, in some direction or, on the contrary, of blocking phenomena. We start by proving the well-posedness of the problem. Then we prove that when the domain has a decreasing cross section with respect to the direction of propagation there is complete propagation. Further, we prove that the wave can be blocked as it comes to an abrupt geometry change. Finally we discuss various general geometrical properties that ensure either partial or complete invasion by 1. In particular, we show that in a domain that is "star-shaped" with respect to an axis, there is complete invasion by 1
Application of photon detectors in the VIP2 experiment to test the Pauli Exclusion Principle

The Pauli Exclusion Principle (PEP) was introduced by the austrian physicist Wolfgang Pauli in 1925. Since then, several experiments have checked its validity. From 2006 until 2010, the VIP (Violation of the Pauli Principle) experiment took data at the LNGS underground laboratory to test the PEP. This experiment looked for electronic 2p to Is transitions in copper, where 2 electrons are in the Is state before the transition happens. These transitions violate the PEP. The lack of detection of X-ray photons coming from these transitions resulted in a preliminary upper limit for the violation of the PEP of 4.7 × 10^-29. Currently, the successor experiment VIP2 is under preparation. The main improvements are, on one side, the use of Silicon Drift Detectors (SDDs) as X-ray photon detectors. On the other side an active shielding is implemented, which consists of plastic scintillator bars read by Silicon Photomultipliers (SiPMs). The employment of these detectors will improve the upper limit for the violation of the PEP by around 2 orders of magnitude
Data provenance and management in radio astronomy: a stream computing approach

New approaches for data provenance and data management (DPDM) are required for mega science projects like the Square Kilometer Array, characterized by extremely large data volume and intense data rates, therefore demanding innovative and highly efficient computational paradigms. In this context, we explore a stream-computing approach with the emphasis on the use of accelerators. In particular, we make use of a new generation of high performance stream-based parallelization middleware known as InfoSphere Streams. Its viability for managing and ensuring interoperability and integrity of signal processing data pipelines is demonstrated in radio astronomy.

IBM InfoSphere Streams embraces the stream-computing paradigm. It is a shift from conventional data mining techniques (involving analysis of existing data from databases) towards real-time analytic processing. We discuss using InfoSphere Streams for effective DPDM in radio astronomy and propose a way in which InfoSphere Streams can be utilized for large antennae arrays. We present a case-study: the InfoSphere Streams implementation of an autocorrelating spectrometer, and using this example we discuss the advantages of the stream-computing approach and the utilization of hardware accelerators
Unipolarization of ambipolar organic field effect transistors toward 
high-impedance complementary metal-oxide-semiconductor circuits

Ambipolar organic field effect transistors (OFETs), consisting of a composite of polyhexylthiophene (PHT) and [6,6]-phenyl C61-butylic acid methyl ester (PCBM), was converted into a p- or n-type OFET by insertion of a thin tetracyanoquinodimethane (TCNQ) or tetrathiafluvalene (TTF) buffer layer. The interface in the Au/TCNQ/PHT:PCBM composite transports hole but blocks electron, while the transported carrier was switched to electron with insertion of a TTF layer. The selective transport is probably due to vacuum level matching or temporal doping. High impedance in a complementary metal-oxide-semiconductor inverter was demonstrated with unipolarized ambipolar FETs, resulting in a decrease in the through current
The impact of the great recession on employment polarization in Spain

This article analyzes changes in the occupational employment share in Spain for the period 1997-2012 and the way particular sociodemographic groups adapt to those changes. There seems to be clear evidence of employment polarization between 1997 and 2012 that accelerates over the recession. Changes in the composition of the labour supply cannot explain the increase in the share of occupations at the low end of the wage distribution. Sector reallocation may have partially contributed to explain the polarization process in Spain during the years of expansion (1997-2007) but it is a minor factor during the recession. The polarization of occupations within sectors observed, especially during the recession, appears to be related to a decline in routine tasks which is compensated by an increase in occupations with non-routine service contents, which are found both in the low and high end of the wage distribution. Instead, jobs with a higher degree of abstract contents do not appear to increase their share in total employment during these 15 years. The paper finds that this process has affected males more strongly than females because of their higher concentration in occupations more focused on routine tasks. Among males, for workers under 30 years old, we find a decrease in the share of occupations with more routine tasks which turns into increases in those with more abstract content and particularly with more non-routine service content. Instead, male workers over 30 years old seem to remain in declining occupations to a greater extent. Females of different ages are not affected by the abovementioned changes
Upscaledb: Efficient Integer-Key Compression in a Key-Value Store using
  SIMD Instructions

Compression can sometimes improve performance by making more of the data
available to the processors faster. We consider the compression of integer keys
in a B+-tree index. For this purpose, systems such as IBM DB2 use variable-byte
compression over differentially coded keys. We revisit this problem with
various compression alternatives such as Google's VarIntGB, Binary Packing and
Frame-of-Reference. In all cases, we describe algorithms that can operate
directly on compressed data. Many of our alternatives exploit the
single-instruction-multiple-data (SIMD) instructions supported by modern CPUs.
We evaluate our techniques in a database environment provided by Upscaledb, a
production-quality key-value database. Our best techniques are SIMD
accelerated: they simultaneously reduce memory usage while improving
single-threaded speeds. In particular, a differentially coded SIMD
binary-packing techniques (BP128) can offer a superior query speed (e.g., 40%
better than an uncompressed database) while providing the best compression
(e.g., by a factor of ten). For analytic workloads, our fast compression
techniques offer compelling benefits. Our software is available as open source
Metabolic potential of endophytic bacteria

The bacterial endophytic microbiome promotes plant growth and health and beneficial effects are in many cases mediated and characterized by metabolic interactions. Recent advances have been made in regard to metabolite production by plant microsymbionts showing that they may produce a range of different types of metabolites. These substances play a role in defense and competition, but may also be needed for specific interaction and communication with the plant host. Furthermore, few examples of bilateral metabolite production are known and endophytes may modulate plant metabolite synthesis as well. We have just started to understand such metabolic interactions between plants and endophytes, however, further research is needed to more efficiently make use of beneficial plant-microbe interactions and to reduce pathogen infestation as well as to reveal novel bioactive substances of commercial interest
Protein search for multiple targets on DNA

Protein-DNA interactions are crucial for all biological processes. One of the most important fundamental aspects of these interactions is the process of protein searching and recognizing specific binding sites on DNA. A large number of experimental and theoretical investigations have been devoted to uncovering the molecular description of these phenomena, but many aspects of the mechanisms of protein search for the targets on DNA remain not well understood. One of the most intriguing problems is the role of multiple targets in protein search dynamics. Using a recently developed theoretical framework we analyze this question in detail. Our method is based on a discrete-state stochastic approach that takes into account most relevant physical-chemical processes and leads to fully analytical description of all dynamic properties. Specifically, systems with two and three targets have been explicitly investigated. It is found that multiple targets in most cases accelerate the search in comparison with a single target situation. However, the acceleration is not always proportional to the number of targets. Surprisingly, there are even situations when it takes longer to find one of the multiple targets in comparison with the single target. It depends on the spatial position of the targets, distances between them, average scanning lengths of protein molecules on DNA, and the total DNA lengths. Physical-chemical explanations of observed results are presented. Our predictions are compared with experimental observations as well as with results from a continuum theory for the protein search. Extensive Monte Carlo computer simulations fully support our theoretical calculations
Using stand-scale forest models for estimating indicators of sustainable forest management

Criteria and indicators (C & I) to evaluate the sustainability of forest management have been proposed by the Ministerial Conference on the Protection of Forests in Europe. Although primarily defined at the national scale, these C & I also have implications at scales ranging from forest stands to the forest management unit. In this paper, we review existing forest growth and ecosystem models from the point of view of applicability to prediction of indicators of sustainable management, focusing on stand scale models and management. To do this, we first present a conceptual framework for understanding the role of models in assessing forest management at the stand level in the context of sustainability criteria and indicators. We classify the criteria into those predictable using models operating at the stand scale, and those derivable either through scaling up or as solutions of a multi-objective management optimisation problem.\ud
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We conclude that to date, no comprehensive models exist that could be used to predict all the indicators simultaneously. The most promising approach seems to be a modular system where different models are combined and run simultaneously, with shared inputs and well defined mutual links. More modelling efforts are needed especially regarding the state of the soil, including carbon, nitrogen and water balances and physical effects. Models also need development in their ability to deal with heterogeneous stand structures and with non-woody forest products such as berries, mushrooms or cork. The outputs of the models need to be developed in a direction where they can be interpreted in terms of the recreational or biodiversity value of the forest.\ud
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Data requirements are most pronounced on the same issues as the gaps in model availability. It would be important to consider amending the national forest inventories and other similar standard data collection protocols with variables required for sustainability assessment. Importantly, combining different models in a modular system and with variable data sources requires advanced model parameterisation and evaluation methods and assessment of parameter and model uncertainty. The probabilistic, Bayesian approaches hold a lot of promise in this respect. Predictions using several different models or model systems, with systematic analysis of e.g. inter-model variability, could also be considered
Highly efficient polarized polymer light-emitting diodes utilizing oriented films of beta-phase poly(9,9-dioctylfluorene)

Uniaxially oriented films of beta-phase poly(9,9-dioctylfluorene) (PFO) were realized by a friction-transfer technique followed by thermal annealing and vapor treatments. Absorption and photoluminescence (PL) spectra show the characteristics of beta-phase: an additional absorption peak at 433 nm and redshifted PL peaks compared with those of the usual nematic (N) phase. We fabricated polarized polymer light-emitting diodes utilizing oriented films of beta-phase PFO. Highly polarized beta-phase emission with an integrated polarization ratio of 51 was observed from the devices. The efficiency of the devices based on beta-phase reached 2.0 cd/A, which is two times higher than that based on N-phase
Ontology-based composition and matching for dynamic service coordination

Service engineering needs to address integration problems allowing services to collaborate and coordinate. The  need to address dynamic  automated changes - caused by on-demand environments and changing requirements - can be addressed through service coordination based on ontology-based composition and matching techniques. Our solution to composition and matching utilises a service coordination space that acts as a passive infrastructure for collaboration. We discuss the information models and the coordination principles of such a collaboration environment in terms of an ontology and its underlying description logics. We provide ontology-based solutions for structural composition of descriptions and matching between requested and provided services
Novel measurements of anomalous triple gauge couplings for the LHC

Finding better ways to prove the Standard Model Effective Field Theory is a very important direction of research. This paper focuses on measurements of Electroweak triple gauge couplings, paying special attention on the regime of validity of the Effective Field Theory (EFT). In this regard, one of our goals is to find measurements leading to a large increase of the interference between the SM amplitude and the contribution of irrelevant operators in the EFT. We propose two such distributions that will lead to a better accuracy. Improvements compared to the traditional methods as well as LHC high luminosity prospects are discussed
Dimensionality and gender-based measurement invariance of the Compassion Scale in a community sample

Compassion has been proposed as relevant to psychological functioning and mental health, involving being compassionate and caring towards others in times of difficulty. The Compassion Scale (CS) proposes to assess compassion for others considering its different dimensions (Kindness; Common humanity; Mindfulness; Indifference; Separation, and Disengagement) and also offers a total score. The current work investigated the psychometric properties of the Portuguese version of this instrument in adults (N=610). Results showed the acceptability of a two higher-order factor solution representing a negative and a positive valence of compassion (i.e., Compassion and Disconnectedness), with each higher-order factor comprising three different dimensions of compassion. Multi-group analyses established measurement invariance across gender; further mean comparison analyses showed that women presented higher levels of the positive dimensions of compassion, whereas men showed higher levels of the negative ones. The CS demonstrated good internal consistency, test-retest reliability, and limited validity in relation to external variables. Overall, these findings contribute to the validation of the CS in a non-clinical adult sample, supporting a new measurement model that partially concurs with the original one. It thus provides the user with a new way of assessing and interpreting compassion that may be useful both in research and clinical settings
Surface plasmon–exciton transition in ultra-thin silver and silver iodide films

Abstract  Silver thin films in the thickness range 2–10 nm produced by thermal evaporation onto glass substrates were systematically iodized and carefully characterized by X-ray diffraction, atomic force microscopy (AFM) and optical absorption spectroscopy. While the uniodized films are X-ray amorphous in keeping with their quasi-continuous nature and 2D islanded structure, briefly iodized films showed characteristic beta AgI structure. Most interestingly, AFM of Ag films revealed uniform triangle-shaped embryos whose shape does not change appreciably upon iodization. Optical absorption spectra of uniodized Ag films show intense surface plasmon resonance (SPR) features with maxima at 440, 484 and 498 nm for the films of thicknesses 2, 5 and 10 nm, respectively, with 5 nm films showing properties characteristic of optimally matched dielectric and electronic properties of the substrate and sample, respectively. Finally, an interesting and unique SPR–exciton phase transition is observed as the ultra-thin films are progressively iodized. These Ag and AgI films could be promising candidates for plasmonic and nanophotonic applications.http://dx.doi.org/10.1007/s00340-007-2768-
Exact scattering matrix of graphs in magnetic field and quantum noise

We consider arbitrary quantum wire networks modelled by finite, noncompact, connected quantum graphs in the presence of an external magnetic field. We find a general formula for the total scattering matrix of the network in terms of its local scattering properties and its metric structure. This is applied to a quantum ring with $N$ external edges. Connecting the external edges of the ring to heat reservoirs, we study the quantum transport on the graph in ambient magnetic field. We consider two types of dynamics on the ring: the free Schr\"odinger and the free massless Dirac equations. For each case, a detailed study of the thermal noise is performed analytically. Interestingly enough, in presence of a magnetic field, the standard linear Johnson-Nyquist law for the low temperature behaviour of the thermal noise becomes nonlinear. The precise regime of validity of this effect is discussed and a typical signature of the underlying dynamics is observed
Centrifugally-driven sample extraction, preconcentration and purification in microfluidic compact discs

Centrifugally driven micro-fluidic discs (µ-CDs) have attracted significant interest within the analytical science community over the last decade, primarily being focused on the potential of such platforms for performing parallel and/or multiplex biological assays and further application in biomedical diagnostics. More recently, µ-CD based devices have also been applied to environmental analysis as platforms for multi-sample extraction and transportation, prior to off-disc analysis in the laboratory. Therefore, this review critically summarises recent developments with µ-CD platforms for sample extraction, preconcentration, fractionation and purification in bioanalytical and environmental applications. In addition to also summarising the 10 common methods employed in the fabrication of µCD platforms, as applications of µ-CDs in sample extraction are generally based on enclosed series of extraction phases/micro-columns, the preparation of these stationary phases in micro-fluidic channels embedded in µ-CDs is also discussed
Limits on coupling between dark components

DM--DE coupling can be a phenomenological indication of a common origin of
the dark cosmic components. In this work we outline a new constraint to
coupled--DE models: the coupling can partially or totally suppress the Meszaros
effect, yielding transfered spectra with quite a soft bending above
$k_{hor,eq}$. Models affected by this anomaly do not show major variation in
the CMB anisotropy spectrum and it is herefore hard to reconcile them with both
CMB and deep sample data, through the same value of the primeval spectral
index