306 research outputs found
Second-order asymptotic expansion and thermodynamic interpretation of a fast-slow Hamiltonian system
This article includes a short survey of selected averaging and dimension
reduction techniques for deterministic fast-slow systems. This survey includes,
among others, classical techniques, such as the WKB approximation or the
averaging method, as well as modern techniques, such as the GENERIC formalism.
The main part of this article combines ideas of some of these techniques and
addresses the problem of deriving a reduced system for the slow degrees of
freedom (DOF) of a fast-slow Hamiltonian system. In the first part, we derive
an asymptotic expansion of the averaged evolution of the fast-slow system up to
second-order, using weak convergence techniques and two-scale convergence. In
the second part, we determine quantities which can be interpreted as
temperature and entropy of the system and expand these quantities up to
second-order, using results from the first part. The results give new insights
into the thermodynamic interpretation of the fast-slow system at different
scales
Second-order fast-slow dynamics of non-ergodic Hamiltonian systems:Thermodynamic interpretation and simulation
A class of fast-slow Hamiltonian systems with potential
describing the interaction of non-ergodic fast and slow degrees of freedom is
studied. The parameter indicates the typical timescale ratio of
the fast and slow degrees of freedom. It is known that the Hamiltonian system
converges for to a homogenised Hamiltonian system. We study
the situation where is small but positive. First, we rigorously
derive the second-order corrections to the homogenised (slow) degrees of
freedom. They can be decomposed into explicitly given terms that oscillate
rapidly around zero and terms that trace the average motion of the corrections,
which are given as the solution to an inhomogeneous linear system of
differential equations. Then, we analyse the energy of the fast degrees of
freedom expanded to second-order from a thermodynamic point of view. In
particular, we define and expand to second-order a temperature, an entropy and
external forces and show that they satisfy to leading-order, as well as on
average to second-order, thermodynamic energy relations akin to the first and
second law of thermodynamics. Finally, we analyse for a specific fast-slow
Hamiltonian system the second-order asymptotic expansion of the slow degrees of
freedom from a numerical point of view. Their approximation quality for short
and long time frames and their total computation time are compared with those
of the solution to the original fast-slow Hamiltonian system of similar
accuracy
Predator avoidance in extremophile fish
Extreme habitats are often characterized by reduced predation pressures, thus representing refuges for the inhabiting species. The present study was designed to investigate predator avoidance of extremophile populations of Poecilia mexicana and P. sulphuraria that either live in hydrogen sulfide-rich (sulfidic) springs or cave habitats, both of which are known to have impoverished piscine predator regimes. Focal fishes that inhabited sulfidic springs showed slightly weaker avoidance reactions when presented with several naturally occurring predatory cichlids, but strongest differences to populations from non-sulfidic habitats were found in a decreased shoaling tendency with non-predatory swordtail (Xiphophorus hellerii) females. When comparing avoidance reactions between P. mexicana from a sulfidic cave (Cueva del Azufre) and the adjacent sulfidic surface creek (El Azufre), we found only slight differences in predator avoidance, but surface fish reacted much more strongly to the non-predatory cichlid Vieja bifasciata. Our third experiment was designed to disentangle learned from innate effects of predator recognition. We compared laboratory-reared (i.e., predator-naïve) and wild-caught (i.e., predator-experienced) individuals of P. mexicana from a non-sulfidic river and found no differences in their reaction towards the presented predators. Overall, our results indicate (1) that predator avoidance is still functional in extremophile Poecilia spp. and (2) that predator recognition and avoidance reactions have a strong genetic basis
Mechanical losses in low loss materials studied by Cryogenic Resonant Acoustic spectroscopy of bulk materials (CRA spectroscopy)
Mechanical losses of crystalline silicon and calcium fluoride have been
analyzed in the temperature range from 5 to 300 K by our novel mechanical
spectroscopy method, cryogenic resonant acoustic spectroscopy of bulk materials
(CRA spectrocopy). The focus lies on the interpretation of the measured data
according to phonon-phonon interactions and defect induced losses in
consideration of the excited mode shape.Comment: 4 pages, 4 figures, proceedings of the PHONONS 2007, submitted to
Journal of Physics: Conference Serie
Schwäbisch-Hällisches Pig
The traditional, local breed Schwäbisch-Hällisches Schwein is originally located in the region of Hohenlohe in Baden-Württemberg, which still is the main breeding area. The breed was developed since nearly 200 years ago by the local farmers and is well adapted to the regional conditions. Next to the genetic value of the old breed in terms of biodiversity, it is the basement for a sustainable local pork chain. In terms of scientific substantiation, their performances and products are mainly untapped. Thus the aim of the present chapter is to present history and current status of Schwäbisch-Hällisches pig breed, its exterior phenotypic characteristics, geographical location, production system and main products from this German autochthonous breed of pigs, one of the local pig breeds investigated in the project TREASURE. Moreover, a collection and review of available literature data, available until August 2017, on reproductive and productive traits of Schwäbisch-Hällisches pig breed were carried out. Meat quality of longissimus muscle completed the conventional productive traits as it is of great interest in autochthonous breeds. Although studies on Schwäbisch-Hällisches pig are scarce, current review gives the first insight into this local pig breed
Diffusion based degradation mechanisms in giant magnetoresistive spin valves
Spin valve systems based on the giant magnetoresistive (GMR) effect as used
for example in hard disks and automotive applications consist of several
functional metallic thin film layers. We have identified by secondary ion mass
spectrometry (SIMS) two main degradation mechanisms: One is related to oxygen
diffusion through a protective cap layer, and the other one is interdiffusion
directly at the functional layers of the GMR stack. By choosing a suitable
material as cap layer (TaN), the oxidation effect can be suppressed.Comment: 3 pages, 3 figures. to be published in Appl. Phys. Let
Using a multi-level tailored design process to develop a customer satisfaction survey for university evaluation
A multi-level procedure is described in order to develop a total quality management survey tool in the field of engineering academia. As a first step a review of
available evaluation tools for universities is conducted, resulting in over 150 items used for evaluation purposes. Secondly all dimensions of educational evaluation used in previous research are summarized, resulting in 15 dimensions. In a third step, items are assigned to the dimensions, overlapping items were combined or removed, and item content and dimensions were adjusted to the specific conditions of the target faculty. Fourthly, the resulting twelve dimensions were used in first, investigative interviews in the target population. Results indicate that eleven dimensions sufficiently mapped all aspects of evaluation. After revising the items to improve understanding in a fifth step cognitive pretests were conducted. The final revision resulted in 83 items assigned to eleven dimensions
Synthesis, Structure, and Reactivity of Disiloxa[3]tetrelocenophanes
Tetramethyldisiloxa[3]metallocenophanes of the heavy group 14 elements germanium, 2a, tin, 2b, and lead, 2c, (tetrelocenophanes) have been synthesized by the reaction of dilithiated ligand, 1, with the corresponding element(II) chloride. The plumbocenophane, 2c, forms one-dimensional coordination polymers in the solid state, while the germanocenophane, 2a, and the stannocenophane, 2b, are monomeric. Furthermore, the reactivity of the stannocenophane, 2b, and the plumbocenophane, 2c, toward N-heterocyclic carbenes was explored. Although the coordination of carbene is reversible in solution at room temperature, the corresponding carbene complexes, 3a,b, could be structurally characterized, illustrating the Lewis acidity of the central atom in these metallocenophanes
Empirical competence-testing: A psychometric examination of the German version of the Emotional Competence Inventory
The “Emotional Competence Inventory“ (ECI 2.0) by Goleman and Boyatzis assesses emotional intelligence (EI) in organizational context by means of 72 items in 4 clusters (self-awareness, self- management, social awareness, social skills) which at large consist of 18 competencies. Our study examines the psychometric properties of the first German translation of this instrument in two different surveys (N = 236). If all items are included in reliability analysis the ECI is reliable (Cronbach’s Alpha = .90), whereas the reliability of the four sub dimensions is much smaller (Alpha = .62 - .81). For 43 items the corrected item-total correlation with its own scale is higher than correlations with the other three clusters. Convergent validity was examined by using another EI instrument (Wong & Law, 2002). We found a significant correlation between the two instruments (r = .41). The German version of the ECI seems to be quite useful, although the high reliability is achieved by a large number of items. Possibilities of improvement are discussed
Emotional Intelligence and its consequences for occupational and life satisfaction - Emotional Intelligence in the context of irrational beliefs
According to Albert Ellis' theory of Rational Emotive Behavior Therapy irrational beliefs (IB) lead to maladaptive emotions. A central component of irrationality is the denial of one's own possibilities to control important aspects of life. A specific IB is that one cannot control and thus cannot avoid certain emotion states. Emotion research considers regulative emotion control a pivotal component of the concept of emotional intelligence (EI). A negative association between IB and EI can thus be theoretically derived from both concepts. Furthermore both should be related to life satisfaction. We examined the relationship between IB and EI using standardized questionnaire instruments and the predictive value of both concepts regarding life satisfaction. We found a significant negative correlation between both conceptions (r = -.21). Life satisfaction and occupational satisfaction are better predicted by IB. R² increases from .04 to .12 when both concepts are incorporated in regression analysis
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