3,880 research outputs found
Histo-anatomy and in vitro morphogenesis in Hyssopus officinalis L. (Lamiaceae)
The sequence of histogenesis and organogenesis in the calus of Hyssopus officinalis nodal explants was studied during treatment with growth regulators. This process represents an important indicator of the accommodation capacity of regenerated plantlets to the ex vitro
conditions. The cell multiplication rate was stimulated in Murashige and Skoog medium supplemented with indole-3-butyric acid (1 mg L–1). The study was carried out from the start of the culture until the development of shoots. Leaf and stem anatomy was influenced by growth regulators. Combinations between auxine and citokinine have induced callus development at the basis of the regenerated shoots, revealing different degrees of vitrification in stems and leaves
Direct Detection of Leptophilic Dark Matter in a Model with Radiative Neutrino Masses
We consider an electro-weak scale model for Dark Matter (DM) and radiative
neutrino mass generation. Despite the leptophilic nature of DM with no direct
couplings to quarks and gluons, scattering with nuclei is induced at the 1-loop
level through photon exchange. Effectively, there are charge-charge,
dipole-charge and dipole-dipole interactions. We investigate the parameter
space consistent with constraints from neutrino masses and mixing, charged
lepton-flavour violation, perturbativity, and the thermal production of the
correct DM abundance, and calculate the expected event rate in DM direct
detection experiments. We show that current data from XENON100 start to
constrain certain regions of the allowed parameter space, whereas future data
from XENON1T has the potential to significantly probe the model.Comment: 24 pages, 8 figures, 2 tables, discussion of large theta13 added,
version to appear in PR
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Effects of Surface Roughness on the Electrochemical Reduction of CO2 over Cu
We have investigated the role of surface roughening on the CO2 reduction reaction (CO2RR) over Cu. The activity and product selectivity of Cu surfaces roughened by plasma pretreatment in Ar, O2, or N2 were compared with that of electrochemically polished Cu samples. Differences in total and product current densities, the ratio of current densities for HER (the hydrogen evolution reaction) to CO2RR, and the ratio of current densities for C2+ to C1 products depend on the electrochemically active surface and are nearly independent of plasma composition. Theoretical analysis of an electropolished and roughened Cu surface reveals a higher fraction of undercoordinated Cu sites on the roughened surface, sites that bind CO preferentially. Roughened surfaces also contain square sites similar to those on a Cu(100) surface but with neighboring step sites, which adsorb OC-COH, a precursor to C2+ products. These findings explain the increases in the formation of oxygenates and hydrocarbons relative to CO and the ratio of oxygenates to hydrocarbons observed with increasing surface roughness
Specific Mathematical Aspects of Dynamics Generated by Coherence Functions
This study presents specific aspects of dynamics generated by the coherence function (acting in an integral manner). It is considered that an oscillating system starting to work from initial nonzero conditions is commanded by the coherence function between the output of the system and an alternating function of a certain frequency. For different initial conditions, the evolution of the system is analyzed. The equivalence between integrodifferential equations and integral equations implying the same number of state variables is investigated; it is shown that integro-differential equations of second order are far more restrictive regarding the initial conditions for the state variables. Then, the analysis is extended to equations of evolution where the coherence function is acting under the form of a multiple integral. It is shown that for the coherence function represented under the form of an nth integral, some specific aspects as multiscale behaviour suitable for modelling transitions in complex systems (e.g., quantum physics) could be noticed when n equals 4, 5, or 6
Relativistic Short Range Phenomena and Space-Time Aspects of Pulse Measurements
Particle physics is increasingly being linked to engineering applications via electron
microscopy, nuclear instrumentation, and numerous other applications. It is well known that
relativistic particle equations notoriously fail over very short space-time intervals. This paper
introduces new versions of Dirac's equation and of the Klein-Gordon equation that are suitable for
short-range phenomena. Another objective of the paper is to demonstrate
that pulse measurement methods that are based on the wave nature of matter
do not necessarily correlate with physical definitions that are based on
the corpuscular nature of particles
Resistant arterial hypertension in a patient with adrenal incidentaloma multiple steno-obstructive vascular lesions and antiphospholipid syndrome
Resistant hypertension is defined as above of blood pressure (≤ 140/90 mmHg) despite therapy with three or more antihypertensive drugs of different classes at maximum tolerable doses with one bling a diuretic. An important consideration in defining a patient with resistant hypertension is the mislabeling of secondary hypertension as resistant hypertension. Here, we report a patients with resistant hypertension caused by multiple stenoocclusive arteries due to antiphospholipid syndrome and coexisting with subclinical Cushing’s syndrome
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Long-term stability studies of a semiconductor photoelectrode in three-electrode configuration
Improving the stability of semiconductor materials is one of the major challenges for sustainable and economic photoelectrochemical water splitting. N-terminated GaN nanostructures have emerged as a practical protective layer for conventional high efficiency but unstable Si and III-V photoelectrodes due to their near-perfect conduction band-alignment, which enables efficient extraction of photo-generated electrons, and N-terminated surfaces, which protects against chemical and photo-corrosion. Here, we demonstrate that Pt-decorated GaN nanostructures on an n+-p Si photocathode can exhibit an ultrahigh stability of 3000 h (i.e., over 500 days for usable sunlight ∼5.5 h per day) at a large photocurrent density (>35 mA cm-2) in three-electrode configuration under AM 1.5G one-sun illumination. The measured applied bias photon-to-current efficiency of 11.9%, with an excellent onset potential of ∼0.56 V vs. RHE, is one of the highest values reported for a Si photocathode under AM 1.5G one-sun illumination. This study provides a paradigm shift for the design and development of semiconductor photoelectrodes for PEC water splitting: stability is no longer limited by the light absorber, but rather by co-catalyst particles
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