455 research outputs found
Choreographies with Secure Boxes and Compromised Principals
We equip choreography-level session descriptions with a simple abstraction of
a security infrastructure. Message components may be enclosed within (possibly
nested) "boxes" annotated with the intended source and destination of those
components. The boxes are to be implemented with cryptography. Strand spaces
provide a semantics for these choreographies, in which some roles may be played
by compromised principals. A skeleton is a partially ordered structure
containing local behaviors (strands) executed by regular (non-compromised)
principals. A skeleton is realized if it contains enough regular strands so
that it could actually occur, in combination with any possible activity of
compromised principals. It is delivery guaranteed (DG) realized if, in
addition, every message transmitted to a regular participant is also delivered.
We define a novel transition system on skeletons, in which the steps add
regular strands. These steps solve tests, i.e. parts of the skeleton that could
not occur without additional regular behavior. We prove three main results
about the transition system. First, each minimal DG realized skeleton is
reachable, using the transition system, from any skeleton it embeds. Second, if
no step is possible from a skeleton A, then A is DG realized. Finally, if a DG
realized B is accessible from A, then B is minimal. Thus, the transition system
provides a systematic way to construct the possible behaviors of the
choreography, in the presence of compromised principals
Policultivo de amaranto con leguminosas, una alternativa de manejo agroecológico de malezas para agricultores familiares de la provincia de Buenos Aires
La necesidad de un sistema agropecuario más sustentable, ecológicamente adecuado, y socialmente aceptable, que provea una alimentación variada y de calidad, es hoy una realidad en la Provincia de Buenos Aires. El cultivo del amaranto (Amaranthus sp.), alimento altamente nutritivo y con gran potencial para adaptarse a las condiciones agroecológicas de la provincia de Buenos Aires, es una posibilidad. Una de sus dificultades es el control de malezas sin uso de agroquímicos. El objetivo de este trabajo es evaluar, desde un enfoque agroecológico, el uso de policultivos con leguminosas (Vicia villosa y Trifolium pratense), como alternativa a dicho problema. Los resultados de esta experiencia muestran que el amaranto y las leguminosas, al ocupar nichos ecológicos distintos, no presentan fuerte competencia entre sí y, por lo tanto, la siembra de Vicia villosa con amaranto aparece como una estrategia adecuada para el manejo ecológico de malezas para agricultores familiares de la provincia de Buenos Aires.The need of agricultural system more sustainable, ecologically suitable and aceptable socially, that provides varied and quality alimentation, is now the reality of Province of Buenos Aires. The crop amaranth incorporation (Amaranthus sp.), very nutritious food and with great potential to suit the agro-ecological conditions of the province of Buenos Aires, is a posibility. one of the difficulties is to control weeds without using chemicals. The aim of this study is to evaluate , from an agro-ecological approach , using intercropping with legumes (Vicia villosa and Trifolium pratense), as an alternative to this problem.The results from that experience show that the amaranth and the legumes, occupy differents niches, no significant competition between them, so, the planting of vicia villosa and amaranth appear like suitable strategy to do an ecological management of weeds for family farmers from Province of Buenos Aires.Eje: A1: Sistemas de producción de base agroecológic
Policultivo de amaranto con leguminosas, una alternativa de manejo agroecológico de malezas para agricultores familiares de la provincia de Buenos Aires
La necesidad de un sistema agropecuario más sustentable, ecológicamente adecuado, y socialmente aceptable, que provea una alimentación variada y de calidad, es hoy una realidad en la Provincia de Buenos Aires. El cultivo del amaranto (Amaranthus sp.), alimento altamente nutritivo y con gran potencial para adaptarse a las condiciones agroecológicas de la provincia de Buenos Aires, es una posibilidad. Una de sus dificultades es el control de malezas sin uso de agroquímicos. El objetivo de este trabajo es evaluar, desde un enfoque agroecológico, el uso de policultivos con leguminosas (Vicia villosa y Trifolium pratense), como alternativa a dicho problema. Los resultados de esta experiencia muestran que el amaranto y las leguminosas, al ocupar nichos ecológicos distintos, no presentan fuerte competencia entre sí y, por lo tanto, la siembra de Vicia villosa con amaranto aparece como una estrategia adecuada para el manejo ecológico de malezas para agricultores familiares de la provincia de Buenos Aires.The need of agricultural system more sustainable, ecologically suitable and aceptable socially, that provides varied and quality alimentation, is now the reality of Province of Buenos Aires. The crop amaranth incorporation (Amaranthus sp.), very nutritious food and with great potential to suit the agro-ecological conditions of the province of Buenos Aires, is a posibility. one of the difficulties is to control weeds without using chemicals. The aim of this study is to evaluate , from an agro-ecological approach , using intercropping with legumes (Vicia villosa and Trifolium pratense), as an alternative to this problem.The results from that experience show that the amaranth and the legumes, occupy differents niches, no significant competition between them, so, the planting of vicia villosa and amaranth appear like suitable strategy to do an ecological management of weeds for family farmers from Province of Buenos Aires.Eje: A1: Sistemas de producción de base agroecológic
Shaping, imaging and controlling plasmonic interference fields at buried interfaces
Filming and controlling plasmons at buried interfaces with nanometer (nm) and
femtosecond (fs) resolution has yet to be achieved and is critical for next
generation plasmonic/electronic devices. In this work, we use light to excite
and shape a plasmonic interference pattern at a buried metal-dielectric
interface in a nanostructured thin film. Plasmons are launched from a
photoexcited array of nanocavities and their propagation is filmed via
photon-induced near-field electron microscopy (PINEM). The resulting movie
directly captures the plasmon dynamics, allowing quantification of their group
velocity at approximately 0.3c, consistent with our theoretical predictions.
Furthermore, we show that the light polarization and nanocavity design can be
tailored to shape transient plasmonic gratings at the nanoscale. These results,
demonstrating dynamical imaging with PINEM, pave the way for the fs/nm
visualization and control of plasmonic fields in advanced heterostructures
based on novel 2D materials such as graphene, MoS, and ultrathin metal
films.Comment: 16 pages, 5 figures, 3 supplementary figure
From attosecond to zeptosecond coherent control of free-electron wave functions using semi-infinite light fields
Light-electron interaction in empty space is the seminal ingredient for
free-electron lasers and also for controlling electron beams to dynamically
investigate materials and molecules. Pushing the coherent control of free
electrons by light to unexplored timescales, below the attosecond, would enable
unprecedented applications in light-assisted electron quantum circuits and
diagnostics at extremely small timescales, such as those governing
intramolecular electronic motion and nuclear phenomena. We experimentally
demonstrate attosecond coherent manipulation of the electron wave function in a
transmission electron microscope, and show that it can be pushed down to the
zeptosecond regime with existing technology. We make a relativistic pulsed
electron beam interact in free space with an appropriately synthesized
semi-infinite light field generated by two femtosecond laser pulses reflected
at the surface of a mirror and delayed by fractions of the optical cycle. The
amplitude and phase of the resulting coherent oscillations of the electron
states in energymomentum space are mapped via momentum-resolved ultrafast
electron energy-loss spectroscopy. The experimental results are in full
agreement with our theoretical framework for light-electron interaction, which
predicts access to the zeptosecond timescale by combining semi-infinite X-ray
fields with free electrons.Comment: 22 pages, 6 figure
Ultrafast Momentum-Resolved Probing of Plasmon Thermal Dynamics with Free Electrons
Current advances in ultrafast electron microscopy make it possible to combine
optical pumping of a nanostructure and electron beam probing with
sub{\aa}ngstrom and femtosecond spatiotemporal resolution. We present a theory
predicting that this technique can reveal a rich out-of-equilibrium dynamics of
plasmon excitations in graphene and graphite samples. In a disruptive departure
from the traditional probing of nanoscale excitations based on the
identification of spectral features in the transmitted electrons, we show that
measurement of angle-resolved, energy-integrated inelastic electron scattering
can trace the temporal evolution of plasmons in these structures and provide
momentum-resolved mode identification, thus avoiding the need for
highly-monochromatic electron beams and the use of electron spectrometers. This
previously unexplored approach to study the ultrafast dynamics of optical
excitations can be of interest to understand and manipulate polaritons in 2D
semiconductors and other materials exhibiting a strong thermo-optical response.Comment: 24 pages, 13 figures, 101 reference
Local photo-mechanical stiffness revealed in gold nanoparticles supracrystals by ultrafast small-angle electron diffraction
We demonstrate that highly-ordered two-dimensional crystals of ligand-capped
gold nanoparticles display a local photo-mechanical stiffness as high as that
of solids such as graphite. In out-of equilibrium electron diffraction
experiments, a strong temperature jump is induced in a thin film with a
femtosecond laser pulse. The initial electronic excitation transfers energy to
the underlying structural degrees of freedom, with a rate generally
proportional to the stiffness of the material. With femtosecond small-angle
electron diffraction, we observe the temporal evolution of the diffraction
feature associated to the nearest-neighbor nanoparticle distance. The
Debye-Waller decay for the octanethiol-capped nanoparticles supracrystal, in
particular, is found to be unexpectedly fast, almost as fast as the stiffest
solid known and observed by the same technique, i.e. graphite. Our observations
unravel that local stiffness in a dense supramolecular assembly can be created
by Van der Waals interactions up to a level comparable to crystalline systems
characterized by covalent bonding
Experimental tests in human-robot collision evaluation and characterization of a new safety index for robot operation
This paper describes an experimental procedure consisting of impact tests that simulate a collision of a human head with an industrial robot with the aim to validate a safety index named as New Index for Robots (NIR) and its outputs. The experiments in this paper are based on lab tests. It is an attempt to characterize the NIR index underlying the main parameters that are involved in crash interaction and to highlight limitations and weakness of suggested impact tests
The expanding field of secondary antibody deficiency: causes, diagnosis, and management
Antibody deficiency or hypogammaglobulinemia can have primary or secondary etiologies. Primary antibody deficiency (PAD) is the result of intrinsic genetic defects, whereas secondary antibody deficiency may arise as a consequence of underlying conditions or medication use. On a global level, malnutrition, HIV, and malaria are major causes of secondary immunodeficiency. In this review we consider secondary antibody deficiency, for which common causes include hematological malignancies, such as chronic lymphocytic leukemia or multiple myeloma, and their treatment, protein-losing states, and side effects of a number of immunosuppressive agents and procedures involved in solid organ transplantation. Secondary antibody deficiency is not only much more common than PAD, but is also being increasingly recognized with the wider and more prolonged use of a growing list of agents targeting B cells. SAD may thus present to a broad range of specialties and is associated with an increased risk of infection. Early diagnosis and intervention is key to avoiding morbidity and mortality. Optimizing treatment requires careful clinical and laboratory assessment and may involve close monitoring of risk parameters, vaccination, antibiotic strategies, and in some patients, immunoglobulin replacement therapy (IgRT). This review discusses the rapidly evolving list of underlying causes of secondary antibody deficiency, specifically focusing on therapies targeting B cells, alongside recent advances in screening, biomarkers of risk for the development of secondary antibody deficiency, diagnosis, monitoring, and management
Comparison of potentiation post-activation responses in two dominant hip strength exercises
The aim of this study was to evaluate whether an anterior-posterior (hip thrust [HT]) movement generated higher post-activation potentiation (PAP) levels on broad jump (BJ) in comparison to an axial-component exercise (deadlift [DL]). Fifteen resistance-trained rugby players participated in this study (age, 22.7 ± 1.6; body weight, 89.9 ± 10.6; height, 181.8 ± 6.5; BMI, 27.2 ± 2.3; 1RM DL 1RM, 117 ± 20.6; 1RM HT, 133.3 ± 21.5. Subjects attended four sessions to the laboratory with seven days between each session. Anthropometric measurements and one-repetition maximum (1-RM) estimations for HT and DL (grip width 72 cm) were performed in the first and third sessions, while PAP tests for both exercise protocols were performed during the second and fourth sessions (subjects performed two repetitions at 90% 1-RM with 8 minutes of recovery between HT and DL exercises, and then the BJ was performed). Data were analyzed by a general lineal model (GLM) with repeated measures and a delta analysis (Δ = post – pre) was performed to determine the 95% confidence interval (95% CI) for the mean. The GLM showed both significant difference and large effect size on BJ per Time [pre vs. post] (P > 0.001; ηp2 = 0.990), but no differences on Time x Protocol interaction (P = 0.452; ηp2=0.020) or per Group (0.748; ηp2 = 0.004) were found. There were significant changes [X ± SD, CIs 95%] on BJ after HT (5.2±5.6, 2.1–8.3; P = 0.03) and DL (6.9±5.3, 4.0–9.9: P < 0.001); however, no difference was found between the exercise protocols (P = 0.748). Our results suggest that DL and HP provided with large effects on PAP to improve the BJ outcomes, but there was no difference between these exercises.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
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