pinecone/core-2020-05-10-deduplication huggingface dataset:
Ion acceleration in underdense plasmas by ultra-short laser pulses

We report on the ion acceleration mechanisms that occur during the interaction of an intense and ultrashort laser pulse ( λ > μ I 2 1018 W cm−2 m2) with an underdense helium plasma produced from an ionized gas jet target. In this\ud
unexplored regime, where the laser pulse duration is comparable to the inverse of the electron plasma frequency ωpe, reproducible non-thermal ion bunches have been measured in the radial direction. The two He ion charge states present energy distributions with cutoff energies between 150 and 200 keV, and a striking energy gap around 50 keV appearing consistently for all the shots in a\ud
given density range. Fully electromagnetic particle-in-cell simulations explain the experimental behaviors. The acceleration results from a combination of target normal sheath acceleration and Coulomb explosion of a filament formed around the laser pulse propagation axi
Proof of concept of an imaging system demonstrator for PET applications with SiPM

A PET imaging system demonstrator based on LYSO crystal arrays coupled to SiPM matrices is under construction at the University and INFN of Pisa. Two SiPM matrices, composed of 8×8 SiPM pixels, and 1,5 mm pitch, have been coupled one to one to a LYSO crystals array and read out by a custom electronics system. front-end ASICs were used to read 8 channels of each matrix. Data from each front-end were multiplexed and sent to a DAQ board for the digital conversion; a motherboard collects the data and communicates with a host computer through a USB port for the storage and off-line data processing. In this paper we show the first preliminary tomographic image of a point-like radioactive source acquired with part of the two detection heads in time coincidence
Instituto de Sistemas Fotovoltaicos de Concentración concentration photovoltaics hybrid system first year of operation and improvements

A photovoltaic (PV) hybrid system combines PV with other forms of electricity generation, usually a diesel generator. The system presented in this paper uses concentration photovoltaic (CPV) as the main generator in combination with a storage system and the grid, configured as the backup power supply. The load of the system consists of an air conditioning system of an office building. This paper presents the results obtained from the first months of operation of the CPV hybrid system installed at Instituto de Sistemas Fotovoltaicos de Concentración facilities together with exhaustive simulations in order to model the system behaviour and be able to improve the self-consumption ratio. This system represents a first approach to the use of a CPV in office buildings complemented by an existing AC-coupled hybrid system. The contribution of this paper to the analysis of this new system and the existing tools available for its simulation, at least a part of it, can be considered as a starting point for the development of these kinds of systems
Modifying the atlas of low lunar orbits using inert tethers

For long enough tethers, the coupling of the attitude and orbital dynamics may show non-negligible effects in the orbital motion of a tethered satellite about a central body. In the case of fast rotating tethers the attitude remains constant, on average, up to second order effects. Besides, for a tether rotating in a plane parallel to the equatorial plane of the central body, the attitude?orbit coupling effect is formally equal to the perturbation of the Keplerian motion produced by the oblateness of the central body and, therefore, may have a stabilizing effect in the orbital dynamics. In the case of a tethered satellite in a low lunar orbit, it is demonstrated that feasible tether lengths can help in modifying the actual map of lunar frozen orbit
Demonstration of the operation principles of intermediate band solar cells at room temperature

In this work we report, for the first time at room temperature, experimental results that prove, simultaneously in the same device, the two main physical principles involved in the operation of intermediate band solar cells: (1) the production of sub-bandgap photocurrent by two optical transitions through the intermediate band; (2) the generation of an output voltage which is not limited by the photon energy absorption threshold. These principles, which had always required cryogenic temperatures to be evidenced all together, are now demonstrated at room temperature on an intermediate band solar cell based on InAs quantum dots with Al0.3Ga0.7As barriers
Dendritic and axonal wiring optimization of cortical GABAergic interneurons

The way in which a neuronal tree expands plays an important role in its functional and computational characteristics. We aimed to study the existence of an optimal neuronal design for different types of cortical GABAergic neurons. To do this, we hypothesized that both the axonal and dendritic trees of individual neurons optimize brain connectivity in terms of wiring length. We took the branching points of real three-dimensional neuronal reconstructions of the axonal and dendritic trees of different types of cortical interneurons and searched for the minimal wiring arborization structure that respects the branching points. We compared the minimal wiring arborization with real axonal and dendritic trees. We tested this optimization problem using a new approach based on graph theory and evolutionary computation techniques. We concluded that neuronal wiring is near-optimal in most of the tested neurons, although the wiring length of dendritic trees is generally nearer to the optimum. Therefore, wiring economy is related to the way in which neuronal arborizations grow irrespective of the marked differences in the morphology of the examined interneurons
Study on the efficiency in the numerical integration of size-structured population models: Error and computational cost

Producción CientíficaWe describe a procedure which is useful to select an appropriate numerical method in a
size-structured population model. We consider four different numerical methods based on
finite difference schemes or characteristics curves integration. We compute an analytical
approximation in terms of the discretization parameters for the theoretical error principal
terms and the computational cost. Thus, we show the efficiency curve that allows to select
the best relationship between the discretization parameters for each numerical method.
Finally, we obtain the most efficient numerical method for each test.Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA191U13
Intraseasonal variations of surface and subsurface currents off Java as simulated in a high-resolution OGCM

A high-resolution ocean general circulation model (OGCM) is used to explore dynamics of intraseasonal variability in surface and subsurface currents off Java. The results indicate that the surface current, the so-called South Java Coastal Current (SJCC), is dominated by variations with a period of 90 days. In the subsurface current, which is referred to as the South Java Coastal Undercurrent (SJCU), 60-day variations are the most prominent feature. A normal mode analysis demonstrates that the first baroclinic mode is the leading mode, which accounts for 70% of the total variance, whereas the second baroclinic mode explains 24% of the total variance. The 90-day variations in the SJCC captured mostly by the first baroclinic mode are found to be primarily driven by winds. Those are associated with propagation of the first baroclinic Kelvin waves generated in the central equatorial Indian Ocean. On the other hand, the 60-day variations\ud
in the SJCU enhanced by wind forcing over the eastern equatorial Indian Ocean off Sumatra are mostly captured by the second baroclinic mode
Improvement in the reconstrution method for VAMOS Spectrometer

International audienceThe VAMOS spectrometer operational at GANIL is a large acceptance variable mode spectrometer designed for nuclear reaction studies using radioactive and stable ion beams. The spectrometer coupled with ancillary detectors like EXOGAM has been successfully used in recent experiments on (in)elastic, few nucleon transfer reactions in inverse kinematics and search for nuclei far from stability using deep inelastic transfer reactions In large acceptance spectrometers, the experimental resolution is worsened by aberrations of third and higher orders. Hardware corrections are limited and cannot completely correct the non-linear effects. Thus software reconstruction of trajectories (ray tracing) is essential to obtain the required resolution and identification of the products. A numerical method has been developed for reconstruction of ion trajectories and correction of aberrations in VAMOS. We have devised a procedure to select an optimum subset of closest trajectories for each focal plane event (x, θ, y, ϕ) from the database (generated by an ion-optics calculation). A polynomial fit to the momentum vector of the reaction product in terms of (x, θ, y, ϕ) is made only to this subset. Such an approach is found to give improved resolutions compared to fitting a single polynomial over the entire phase space. Extraction of charge state and angular distributions are rather difficult due to the variation of acceptance over the large phase space. Mass identification of the reaction products and characteristics of the spectrometer acceptance with its variation for different rigidities have been obtained. Applications to 238U+48Ca and 238U+58Ni systems at 5.5 MeV/u will be presented
Appreciating interconnectivity between habitats is key to blue carbon management

We welcome the recent synthesis by Howard et al. (2017), which drew attention to the role of marine systems and natural carbon sequestration in the oceans as a fundamental aspect of climate-change mitigation. The importance of long-term carbon storage in marine habitats (ie ?blue carbon?) is rapidly gaining recognition (Figure 1a) and is increasingly a focus of national and international attempts to mitigate rising atmospheric emissions of carbon dioxide. However, effectively managing blue carbon requires an appreciation of the inherent connectivity between marine populations and habitats. More so than their terrestrial counterparts, marine ecosystems are ?open?, with high rates of transfer of energy, matter, genetic material, and species across regional seascapes (Kinlan and Gaines 2003). We suggest that policy frameworks, and the science underpinning them, should focus not only on carbon sink habitats but also on carbon source habitats, which play critical roles in marine carbon cycling and natural carbon sequestration in the oceans. Howard et al. (2017) concluded that certain habitats and taxa (eg kelp forests, large vertebrates) are "unimportant? in natural carbon sequestration, which we argue is an oversimplification that fails to account for not only the magnitude of carbon transfer between living components of the cycle but also the interconnectedness of the highly dynamic and open marine environment. Crucially, developing carbon budgets for habitats in isolation ? without considering their connectivity and functioning as carbon ?fixers?, ?donors?, and ?recipients? ? is neither representative of marine ecosystems, nor a useful approach for prioritizing management. Here, we highlight the importance of carbon transfer between habitats, which is not currently recognized within policy frameworks, through two pertinent and widespread processesauthorsversionPeer reviewe
Oximetry use in obstructive sleep apnea

Producción CientíficaIntroduction. Overnight oximetry has been proposed as an accessible, simple, and reliable technique for obstructive sleep apnea syndrome (OSAS) diagnosis. From visual inspection to advanced signal processing, several studies have demonstrated the usefulness of oximetry as a screening tool. However, there is still controversy regarding the general application of oximetry as a single screening methodology for OSAS. 
Areas covered. Currently, high-resolution portable devices combined with pattern recognition-based applications are able to achieve high performance in the detection this disease. In this review, recent studies involving automated analysis of oximetry by means of advanced signal processing and machine learning algorithms are analyzed. Advantages and limitations are highlighted and novel research lines aimed at improving the screening ability of oximetry are proposed.
Expert commentary. Oximetry is a cost-effective tool for OSAS screening in patients showing high pretest probability for the disease. Nevertheless, exhaustive analyses are still needed to further assess unattended oximetry monitoring as a single diagnostic test for sleep apnea, particularly in the pediatric population and in especial groups with significant comorbidities. In the following years, communication technologies and big data analysis will overcome current limitations of simplified sleep testing approaches, changing the detection and management of OSAS.This research has been partially supported by the projects DPI2017-84280-R and RTC-2015-3446-1 from Ministerio de Economía, Industria y Competitividad and European Regional Development Fund (FEDER), the project 66/2016 of the Sociedad Española de Neumología y Cirugía Torácica (SEPAR), and the project VA037U16 from the Consejería de Educación de la Junta de Castilla y León and FEDER. D. Álvarez was in receipt of a Juan de la Cierva grant IJCI-2014-22664 from the Ministerio de Economía y Competitividad
Socio-political processes in international management in post-socialist contexts: Knowledge, learning and transnational institution building

This paper contributes to the recent debates and emerging concepts in the international business literature by applying a social–institutionalist perspective that focuses on the processes of institutionbuilding in ventures between Western multinational corporations and post-socialist enterprises. It is argued that the knowledge and learningprocesses within these transnational sites are constitutive of the actual management and organizational practices that emerge in these social microcosms of transformation. In transition and other emerging economic contexts, international ventures are typically based on asymmetrical relationships, in which the balance of power is structurally weighted in favor of the MNC. Notwithstanding this dominance structure, constructing new practices within the transnational social space is a socio-politicalprocess involving power-holders such as senior managers representing the Western MNC and the local enterprise. The paper argues that the strategic orientations of these key power-holders are critical variables in explaining the diversity of concrete patterns of institution building on transnational sites
Age-Related Effects in Working Memory Recognition Modulated by Retroactive Interference

One of the main causes for age-related declines in working memory is a higher vulnerability to retroactive interference due to a reduced ability to suppress irrelevant information. However, the underlying neural correlates remain to be established. Magnetoencephalography was used to investigate differential neural patterns in young and older adults performing an interference-based memory task with two experimental conditions, interrupting and distracting, during successful recognition. Behaviorally, both types of retroactive interference significantly impaired accuracy at recognition more in older adults than in young adults with the latter exhibiting greater disruptions by interrupters. Magnetoencephalography revealed the presence of differential age-related neural patterns. Specifically, time-modulated activations in temporo-occipital and superior parietal regions were higher in young adults compared with older adults for the interrupting condition. These results suggest that age-related deficits in inhibitory mechanisms that increase vulnerability to retroactive interference may be associated with neural under-recruitments in a high-interference task
An upper bound for validity limits of asymptotic analytical approaches based on normal form theory

Perturbation methods are routinely used in all fields of applied mathematics where analytical solutions for nonlinear dynamical systems are searched. Among them, normal form theory provides a reliable method for systematically simplifying dynamical systems via nonlinear change of coordinates, and is also used in a mechanical context to define Nonlinear Normal Modes (NNMs). The main recognized drawback of perturbation methods is the absence of a criterion establishing their range of validity in terms of amplitude. In this paper, we propose a method to obtain upper bounds for amplitudes of changes of variables in normal form transformations. The criterion is tested on simple mechanical systems with one and two degrees-of-freedom, and for complex as well as real normal form. Its behavior with increasing order in the normal transform is established, and comparisons are drawn between exact solutions and normal form computations for increasing levels of amplitudes. The results clearly establish that the criterion gives an upper bound for validity limit of normal transforms
Don't Blame the Idealizations (revised version)

Idealizing conditions are scapegoats for scientific hypotheses, too often blamed for falsehood better attributed to less obvious sources. But while the tendency to blame idealizations is common among both philosophers of science and scientists themselves, the blame is misplaced. Attention to the nature of idealizing conditions, the content of idealized hypotheses, and scientists' attitudes toward those hypotheses shows that idealizing conditions are blameless when hypotheses misrepresent. These conditions help to determine the content of idealized hypotheses, and they do so in a way that prevents those hypotheses from being false by virtue of their constituent idealizations
Kinetics of amorphization induced by swift heavy ions in α-quartz

The kinetics of amorphization in crystalline SiO2 (α-quartz) under irradiation with swift heavy ions (O+1 at 4 MeV, O+4 at 13 MeV, F+2 at 5 MeV, F+4 at 15 MeV, Cl+3 at 10 MeV, Cl+4 at 20 MeV, Br+5 at 15 and 25 MeV and Br+8 at 40 MeV) has been analyzed in this work with an Avrami-type law and also with a recently developed cumulative approach (track-overlap model). This latter model assumes a track morphology consisting of an amorphous core (area σ) and a surrounding defective halo (area h), both being axially symmetric. The parameters of the two approaches which provide the best fit to the experimental data have been obtained as a function of the electronic stopping power Se. The extrapolation of the σ(Se) dependence yields a threshold value for amorphization, Sth ≈ 2.1 keV/nm; a second threshold is also observed around 4.1 keV/nm. We believe that this double-threshold effect could be related to the appearance of discontinuous tracks in the region between 2.1 and 4.1 keV/nm. For stopping power values around or below the lower threshold, where the ratio h/σ is large, the track-overlap model provides a much better fit than the Avrami function. Therefore, the data show that a right modeling of the amorphization kinetics needs to take into account the contribution of the defective track halo. Finally, a short comparative discussion with the kinetic laws obtained for elastic collision damage is given
Conceptual design of the liquid metal laboratory of the TECHNOFUSION facility

The application of liquid metal technology in fusion devices requires R&D related to many phenomena: interaction between liquid metals and structural material as corrosion, erosion and passivation techniques; magneto-hydrodynamics; free surface fluid-dynamics and any other physical aspect that will be needed for their safe reliable operation. In particular, there is a significant shortage of experimental facilities dedicated to the development of the lithium technology. In the framework of the TECHNOFUSION project, an experimental laboratory devoted to the lithium technology development is proposed, in order to shed some light in the path to IFMIF and the design of chamber's first wall and divertors. The conceptual design foresee a development in two stages, the first one consisting on a material testing loop. The second stage proposes the construction of a mock-up of the IFMIF target that will allow to assess the behaviour of a free-surface lithium target under vacuum conditions. In this paper, such conceptual design is addressed
X chromosome inactivation is initiated in human preimplantation embryos

X chromosome inactivation (XCI) is the mammalian mechanism that compensates for the difference in gene dosage between XX females and XY males. Genetic and epigenetic regulatory mechanisms induce transcriptional silencing of one X chromosome in female cells. In mouse embryos, XCI is initiated at the preimplantation stage following early whole-genome activation. It is widely thought that human embryos do not employ XCI prior to implantation. Here, we show that female preimplantation embryos have a progressive accumulation of XIST  RNA on one of the two X chromosomes, starting around the 8-cell stage. XIST  RNA accumulates at the morula and blastocyst stages and is associated with transcriptional silencing of the XIST-coated chromosomal region. These findings indicate that XCI is initiated in female human preimplantation-stage embryos and suggest that preimplantation dosage compensation is evolutionarily conserved in placental mammals
Determination of fluoroquinolone antibiotics in surface waters from Mondego River by high performance liquid chromatography using a monolithic column

A novel LC-fluorescence detection method based on the use of a monolithic column for the determination of norfloxacin, ciprofloxacin, and enrofloxacin antibiotic residues in environmental waters was developed. Fluoroquinolones (FQs) were isocratically eluted using a mobile phase consisting of 0.025 M phosphoric acid solution at pH 3.0 with tetrabutylammonium and methanol (960:40, v/v) through a Chromolith Performance RP-18e column (100×4.6 mm) at a flow rate of 2.5 mL/min and detected at excitation and emission wavelengths of 278 and 450 nm, respectively. After acidification and addition of EDTA, water samples were extracted using an Oasis HLB cartridge. Linearity was evaluated in the range of 0.05 to 1 mug/mL and correlation coefficients of 0.9945 for norfloxacin, 0.9974 for ciprofloxacin, and 0.9982 for enrofloxacin were found. The limit of quantification was 25 ng/L for the three FQs. The recovery of FQs spiked into river water samples at 25, 50, and 100 ng/L fortification levels ranged from 76.5 to 91.0% for norfloxacin, 78.5 to 97.2% for ciprofloxacin, and 79.4 to 93.6% for enrofloxacin. This method was successfully applied to the analysis of water samples from the Mondego River, and ciprofloxacin and enrofloxacin residues were detected in eight water samples.http://dx.doi.org/10.1002/jssc.20070036