Search results for "Standing"

The implications of the EU Labour law in Latvia

2013

Seasonal succession of phytoplankton in an ice-free pond warmed by a thermal power plant

1982

In a pond receiving warmed cooling waters from a thermal power plant, the physical and chemical properties of the water, phytoplankton, periphyton and zooplankton were monitored on a weekly sampling schedule. In winter the phytoplankton growth was limited by poor light conditions. In mid-February a rapid phytoplankton growth started, simultaneously with increasing light energy, high nutrient concentrations and small herbivorous zooplankton populations. The increase of phytoplankton biomass was stopped by lack of free nutrients and silica at the end of March. From May until August the phytoplankton standing crop was mainly regulated by herbivorous zooplankton. The autumnal maximum of phytopl…

INTEGRATING ONTOLOGY AND COGNITIVE LINGUISTICS FOR NATURAL LANGUAGE PRODUCTION AND UNDERSTANDING

2012

Ontologies have been designed to capture the semantic knowledge of a domain in a machine understandable form. Current standards for managing ontologies like OWL are lacking in linguistic grounding, and are not able to achieve a clear link with natural language. Bridging this gap, unskilled users could be able to infer the information described in the ontology and it would be possible either producing or parsing utterances about the represented domain automatically. Moreover, as in the case of enterprises, it could be very useful to extract information from external documental corpora that are related to the same domain. Many attempts have been made with the aim to create a natural language …

On the optimal design of multi-stage cascaded transistor amplifiers with noise, gain and mismatch constraints

2007

The problem of evaluating the optimal performances of cascaded, unbalanced, multi-stage transistor amplifiers is addressed. In particular, a theoretically rigorous approach is proposed for the determination of a family of Optimal Design Curves (ODC's) which express the best noise-gain tradeoff that can be achieved - at each frequency and device operating condition - when a simultaneous constraint on amplifier input VSWR is accounted for. Such curves can be used as a more meaningful starting point in practical amplifier design in place of the approximate calculations so far employed for target performance or optimization goals determination.

2000 Outstanding Intellectuals of the 21st century

2000

2000 Outstanding Intellectuals of the 21st century

When outstanding mathematicians cannot figure out that 14 – 2 = 12

2018

International audience; We investigated what happens when non-mathematical knowledge interferes with mathematical knowledge in arithmetic word problem solving. Adults and expert mathematicians had to evaluate the solutions of basic additive problems. The non-mathematical knowledge evoked by the problems hindered both populations’ success rates and response times when incongruent with the solving algorithm.

Plenty of motion at the bottom: atomically thin liquid gold membrane

2015

The discovery of graphene some ten years ago was the first proof of a free-standing two-dimensional (2D) solid phase. Here, using quantum molecular dynamics simulations of nanoscale gold patches suspended in graphene pores, we predict the existence of an atomically thin, free-standing 2D liquid phase. The liquid phase, enabled by the exceptional planar stability of gold due to relativistic effects, demonstrates extreme fluxionality of metal nanostructures and opens possibilities for a variety of nanoscale phenomena.

Surface waves in solar granulation observed with {\sc Sunrise}

2010

Solar oscillations are expected to be excited by turbulent flows in the intergranular lanes near the solar surface. Time series recorded by the IMaX instrument aboard the {\sc Sunrise} observatory reveal solar oscillations at high resolution, which allow studying the properties of oscillations with short wavelengths. We analyze two times series with synchronous recordings of Doppler velocity and continuum intensity images with durations of 32\thinspace min and 23\thinspace min, resp., recorded close to the disk center of the Sun to study the propagation and excitation of solar acoustic oscillations. In the Doppler velocity data, both the standing acoustic waves and the short-lived, high-deg…

Lineshape-asymmetry elimination in weak atomic transitions driven by an intense standing wave field

2018

Owing to the ac-Stark effect, the lineshape of a weak optical transition in an atomic beam can become significantly distorted, when driven by an intense standing wave field. We use an Yb atomic beam to study the lineshape of the 6s2 1S0 -> 5d6s 3D1 transition, which is excited with light circulating in a Fabry-Perot resonator. We demonstrate two methods to avoid the distortion of the transition profile. Of these, one relies on the operation of the resonator in multiple longitudinal modes, and the other in multiple transverse modes.

Phase-stable free-space optical lattices for trapped ions

2015

We demonstrate control of the absolute phase of an optical lattice with respect to a single trapped ion. The lattice is generated by off-resonant free-space laser beams, we actively stabilize its phase by measuring its ac-Stark shift on a trapped ion. The ion is localized within the standing wave to better than 2\% of its period. The locked lattice allows us to apply displacement operations via resonant optical forces with a controlled direction in phase space. Moreover, we observe the lattice-induced phase evolution of spin superposition states in order to analyze the relevant decoherence mechanisms. Finally, we employ lattice-induced phase shifts for inferring the variation of the ion pos…