3,086 research outputs found
Matter in Toy Dynamical Geometries
One of the objectives of theories describing quantum dynamical geometry is to
compute expectation values of geometrical observables. The results of such
computations can be affected by whether or not matter is taken into account. It
is thus important to understand to what extent and to what effect matter can
affect dynamical geometries. Using a simple model, it is shown that matter can
effectively mold a geometry into an isotropic configuration. Implications for
"atomistic" models of quantum geometry are briefly discussed.Comment: 8 pages, 1 figure, paper presented at DICE 200
Little houses and casas pequenas: Message formulation and syntactic form in unscripted speech with speakers of English and Spanish
During unscripted speech, speakers coordinate the formulation of pre-linguistic messages with the linguistic processes that implement those messages into speech. We examine the process of constructing a contextually appropriate message and interfacing that message with utterance planning in English (the small butterfly) and Spanish (la mariposa pequeña) during an unscripted, interactive task. The coordination of gaze and speech during formulation of these messages is used to evaluate two hypotheses regarding the lower limit on the size of message planning units, namely whether messages are planned in units isomorphous to entire phrases or units isomorphous to single lexical items. Comparing the planning of fluent pre-nominal adjectives in English and post-nominal adjectives in Spanish showed that size information is added to the message later in Spanish than English, suggesting that speakers can prepare pre-linguistic messages in lexically-sized units. The results also suggest that the speaker can use disfluency to coordinate the transition from thought to speech
Quantum Geometry Phenomenology: Angle and Semiclassical States
The phenomenology for the deep spatial geometry of loop quantum gravity is
discussed. In the context of a simple model of an atom of space, it is shown
how purely combinatorial structures can affect observations. The angle operator
is used to develop a model of angular corrections to local, continuum
flat-space 3-geometries. The physical effects involve neither breaking of local
Lorentz invariance nor Planck scale suppression, but rather reply on only the
combinatorics of SU(2) recouping theory. Bhabha scattering is discussed as an
example of how the effects might be observationally accessible.Comment: 5 pages, slightly extended version of the contribution to the
Loops'11 conference proceeding
Modelling the many-body dynamics of heavy ion collisions: Present status and future perspective
Basic problems of the semiclassical microscopic modelling of strongly
interactingsystems are discussed within the framework of Quantum Molecular
Dynamics (QMD). This model allows to study the influence of several types of
nucleonic interactions on a large variety of observables and phenomena
occurring in heavy ion collisions at relativistic energies.It is shown that the
same predictions can be obtained with several -- numerically completely
different and independently written -- programs as far as the same model
parameters are employed and the same basic approximations are made. Many
observables are robust against variations of the details of the model
assumptions used. Some of the physical results, however, depend also on rather
technical parameters like the preparation of the initial configuration in phase
space. This crucial problem is connected with the description of the ground
state of single nuclei,which differs among the various approaches. An outlook
to an improved molecular dynamics scheme for heavy ion collisions is given.Comment: 39 pages, 12 figure
Fir (Abies spp.) stand biomass additive model for Eurasia sensitive to winter temperature and annual precipitation
Climate change, especially modified courses of temperature and precipitation, has a significant impact on forest functioning and productivity. Moreover, some alterations in tree biomass allocation (e.g. root to shoot ratio, foliage to wood parts) might be expected in these changing ecological conditions. Therefore, we attempted to model fir stand biomass (t ha(-1)) along the trans-Eurasian hydrothermal gradients using the data from 272 forest stands. The model outputs suggested that all biomass components, except for the crown mass, change in a common pattern, but in different ratios. Specifically, in the range of mean January temperature and precipitation of -30 degrees C to +10 degrees C and 300 to 900 mm, fir stand biomass increases with both increasing temperature and precipitation. Under an assumed increase of January temperature by 1 degrees C, biomass of roots and of all components of the aboveground biomass of fir stands increased (under the assumption that the precipitation level did not change). Similarly, an assumed increase in precipitation by 100 mm resulted in the increased biomass of roots and of all aboveground components. We conclude that fir seems to be a perspective taxon from the point of its productive properties in the ongoing process of climate change.This paper was prepared within the programs of the current scientific research of the Ural Forest Engineering University and Botanical Garden of the Ural Branch of Russian Academy of Sciences. This work was supported by grant "EVA4.0", No. CZ.02.1.01/0.0/0.0/16_019/0000803 financed by OP RDE, by the Slovak Research and Development Agency under contracts No. APVV-15-0265, APVV-16-0325, APVV-18-0086 and the Scientific Grant Agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic under contracts No. VEGA 1/0367/16
Differences of some chemicals and physical properties of winter wheat grain of mealy and vitreous appearance
Many wheat species and cultivars, independent of genetic markers of hardness, can produce grain with a vitreous, mealy or mixed appearance. This study analyzed selected chemical and physical differences between kernels with a vitreous and mealy appearance, hand-picked from grain of four winter wheat cultivars cultivated in Poland. Separated fractions were examined for protein content and composition, friabilin presence, carotenoids and total phenolic compounds content, specific kernel density, hardness, as well as kernel surface color. It was found that the ratio of vitreous kernels in the cultivars ranged from 39.18% to 76.28%. Vitreous kernels were darker, slightly heavier and harder than mealy kernels. Additionally, these kernels were more abundant in proteins (an average increase of 2.13%, with variation among cultivars from 0.71% to 2.89%). This type of kernels was also richer in phenolic compounds (on average by 4.02%) and less abundant in carotenoids (on average by 4.53%). Mealy (softer) kernels fractured to a finer flour
Word order affects the time course of sentence formulation in Tzeltal
The scope of planning during sentence formulation is known to be flexible, as it can be influenced by speakers' communicative goals and language production pressures (among other factors). Two eye-tracked picture description experiments tested whether the time course of formulation is also modulated by grammatical structure and thus whether differences in linear word order across languages affect the breadth and order of conceptual and linguistic encoding operations. Native speakers of Tzeltal [a primarily verb–object–subject (VOS) language] and Dutch [a subject–verb–object (SVO) language] described pictures of transitive events. Analyses compared speakers' choice of sentence structure across events with more accessible and less accessible characters as well as the time course of formulation for sentences with different word orders. Character accessibility influenced subject selection in both languages in subject-initial and subject-final sentences, ruling against a radically incremental formulation process. In Tzeltal, subject-initial word orders were preferred over verb-initial orders when event characters had matching animacy features, suggesting a possible role for similarity-based interference in influencing word order choice. Time course analyses revealed a strong effect of sentence structure on formulation: In subject-initial sentences, in both Tzeltal and Dutch, event characters were largely fixated sequentially, while in verb-initial sentences in Tzeltal, relational information received priority over encoding of either character during the earliest stages of formulation. The results show a tight parallelism between grammatical structure and the order of encoding operations carried out during sentence formulation
The Free Particle in Deformed Special Relativity
The phase space of a classical particle in DSR contains de Sitter space as
the space of momenta. We start from the standard relativistic particle in five
dimensions with an extra constraint and reduce it to four dimensional DSR by
imposing appropriate gauge fixing. We analyze some physical properties of the
resulting theories like the equations of motion, the form of Lorentz
transformations and the issue of velocity. We also address the problem of the
origin and interpretation of different bases in DSR.Comment: 15 page
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