Delay differential equations driven by Levy processes: stationarity and Feller properties

We consider a stochastic delay differential equation driven by a general Levy process. Both, the drift and the noise term may depend on the past, but only the drift term is assumed to be linear. We show that the segment process is eventually Feller, but in general not eventually strong Feller on the Skorokhod space. The existence of an invariant measure is shown by proving tightness of the segments using semimartingale characteristics and the Krylov-Bogoliubov method. A counterexample shows that the stationary solution in completely general situations may not be unique, but in more specific cases uniqueness is established.Comment: 28 page

Broadband Geodesic Pulses for Three Spin Systems: Time-Optimal Realization of Effective Trilinear Coupling Terms and Indirect SWAP Gates

Broadband implementations of time-optimal geodesic pulse elements are introduced for the efficient creation of effective trilinear coupling terms for spin systems consisting of three weakly coupled spins 1/2. Based on these pulse elements, the time-optimal implementation of indirect SWAP operations is demonstrated experimentally. The duration of indirect SWAP gates based on broadband geodesic sequence is reduced by 42.3% compared to conventional approaches.Comment: 22 pages, incl. 8 figure

Occurence of elliptical fractal patterns in multi-bit bandpass sigma delta modulators

It has been established that the class of bandpass sigma delta modulators (SDMs) with single bit quantizers could exhibit state space dynamics represented by elliptic or fractal patterns confined within trapezoidal regions. In this letter, we find that elliptical fractal patterns may also occur in bandpass SDMs with multibit quantizers, even for the case when the saturation regions of the multibit quantizers are not activated and a large number of bits are used for the implementation of the quantizers. Moreover, the fractal pattern may occur for low bit quantizers, and the visual appearance of the phase portraits between the infinite state machine and the finite state machine with high bit quantizers is different. These phenomena are different from those previously reported for the digital filter with two’s complement arithmetic. Furthermore, some interesting phenomena are found. A bit change of the quantizer can result in a dramatic change in the fractal patterns. When the trajectories of the corresponding linear systems converge to a fixed point, the regions of the elliptical fractal patterns diminish in size as the number of bits of the quantizers increases

Challenges in measuring "connectedness to nature" among indigenous children: lessons from the Negev Bedouin

Culturally adapted tools for measuring connectedness to nature are important, since attitudes and perceptions toward nature cannot be universalized. They are influenced by a wide range of factors, like individuals’ experience in their home environment, safety concerns and a variety of other sociocultural factors. The purpose of this paper is to introduce a model for a cultural adaptation process, through which suitable nature connectedness questionnaires can be created. Our approach is based on “Third Space Theory,” which laid the groundwork for the development of culturally adapted questionnaires that combine Western categories for measuring nature connectedness with elements that specifically reflect the local culture of an indigenous community. The paper details the adaptation process of a questionnaire designed to learn about the nature connectedness of 5th grade students living in unrecognized Bedouin villages in the Negev Desert. The process enlisted the input of 58 fifth grade students (28 boys and 30 girls) and four professionals from the fields of education and environmental education. It incorporated two different types of interviews, personal, semi-structured interviews, and interviews with small groups of students as they orally completed different iterations of the questionnaire. Thematic content analysis was conducted to reveal the various sociocultural aspects of the relationship between Bedouin children and their natural environment. The results of the paper include: (a) the seven-stage development process of the culturally adapted nature connectedness questionnaire, and (b) examples of the types of information that the culturally adapted questionnaire reveals, which a standard nature connectedness questionnaire might not provide

Indigenous children's connectedness to nature: the potential influence of culture, gender and exposure to a contaminated environment

This study investigates the concept of “connectedness to nature” among students from an indigenous Bedouin community, whose relationship with nature is influenced by a variety of cultural, social and environmental factors, not least of which is the fact that the environment in which they live is highly contaminated. We asked 294 fifth- and sixth-grade students (130 boys and 164 girls), who live in the highly rural Bedouin villages in Israel’s Negev desert, to complete an open questionnaire that was specifically designed to elicit detailed information about these particular students’ connection to nature. The paper presents the results of two analyses of this questionnaire. The first—a quantitative analysis—divides the students’ answers into five aspects of connectedness to nature (nature enjoyment, empathy for living creatures, sense of oneness, sense of responsibility and experience of nature in my immediate environment). The second—an inductive, qualitative analysis of the students’ explanations and elaborations of their answers—provides a more nuanced description of the various social, historical and situational factors that influence these students’ relationship with their environment. It then addresses the tension between these two analyses, highlighting the limitations of “traditional” categories of nature connectedness while showing how these can nevertheless be used to elicit detailed, complex and pertinent information. It concludes by demonstrating how this information, if analyzed critically through its correspondence, or lack of correspondence, with the original assumptions of the statements that elicited it, might be used in the development of place-based environmental education programs for specific populations

Dynamics and control of the expansion of finite-size plasmas produced in ultraintense laser-matter interactions

The strong influence of the electron dynamics provides the possibility of controlling the expansion of laser-produced plasmas by appropriately shaping the laser pulse. A simple irradiation scheme is proposed to tailor the explosion of large deuterium clusters, inducing the formation of shock structures, capable of driving nuclear fusion reactions. Such a scenario has been thoroughly investigated, resorting to two- and three-dimensional particle-in-cell simulations. Furthermore, the intricate dynamics of ions and electrons during the collisionless expansion of spherical nanoplasmas has been analyzed in detail using a self-consistent ergodic-kinetic model. This study clarifies the transition from hydrodynamic-like to Coulomb-explosion regimes

Adolescents care but don't feel responsible for farm animal welfare

Adolescents are the next generation of consumers with the potential to raise standards of farm animal welfare—to theirsatisfaction—if their preferences and concerns are translated into accurate market drivers and signals. There are no published data about adolescent views of farm animal welfare to allow meaningful design, implementation, and evaluation of educational strategies to improve consideration of—and behavior toward—farm animals. Knowledge of farm animal welfare, as well as beliefs and attitudes about farm animal welfare and behavioral intention relevant to it were determined in a sample of ukadolescents, using a survey incorporating an extended version of the theory of planned behavior and novel assessment tools. Our results indicate that adolescents have only a limited knowledge of welfare problems for farm animals and welfare-relevant product labels. Intentions to identify welfare standards for the animals from whom their food was derived were weak. Although they cared about farm animal welfare and agreed with fundamental principles—for example, the provision of space and the absence of pain and suffering—like adults they held limited belief in the power and responsibility that they possess through their choices as consumers; responsibility was often shifted to others, such as the government and farmers

Electronic and magnetic structure of epitaxial NiO/Fe3_3O4_4(001) heterostructures grown on MgO(001) and Nb-doped SrTiO3_3(001)

We study the underlying chemical, electronic and magnetic properties of a number of magnetite based thin films. The main focus is placed onto NiO/Fe$_3$O$_4$(001) bilayers grown on MgO(001) and Nb-SrTiO$_3$(001) substrates. We compare the results with those obtained on pure Fe$_3$O$_4$(001) thin films. It is found that the magnetite layers are oxidized and Fe$^{3+}$ dominates at the surfaces due to maghemite ($\gamma$-Fe$_2$O$_3$) formation, which decreases with increasing magnetite layer thickness. From a layer thickness of around 20 nm on the cationic distribution is close to that of stoichiometric Fe$_3$O$_4$. At the interface between NiO and Fe$_3$O$_4$ we find the Ni to be in a divalent valence state, with unambiguous spectral features in the Ni 2p core level x-ray photoelectron spectra typical for NiO. The formation of a significant NiFe$_2$O$_4$ interlayer can be excluded by means of XMCD. Magneto optical Kerr effect measurements reveal significant higher coercive fields compared to magnetite thin films grown on MgO(001), and a 45$^{\circ}$ rotated magnetic easy axis. We discuss the spin magnetic moments of the magnetite layers and find that the moment increases with increasing thin film thickness. At low thickness the NiO/Fe$_3$O$_4$ films grown on Nb-SrTiO$_3$ exhibits a significantly decreased spin magnetic moments. A thickness of 20 nm or above leads to spin magnetic moments close to that of bulk magnetite

Bubble generation in a twisted and bent DNA-like model

The DNA molecule is modeled by a parabola embedded chain with long-range interactions between twisted base pair dipoles. A mechanism for bubble generation is presented and investigated in two different configurations. Using random normally distributed initial conditions to simulate thermal fluctuations, a relationship between bubble generation, twist and curvature is established. An analytical approach supports the numerical results.Comment: 7 pages, 8 figures. Accepted for Phys. Rev. E (in press