Onset of chaotic dynamics in a ball mill: attractors merging and crisis induced intermittency

In mechanical treatment carried out by ball milling, powder particles are subjected to repeated high-energy mechanical loads which induce heavy plastic deformations together with fracturing and cold-welding events. Owing to the continuous defect accumulation and interface renewal, both structural and chemical transformations occur. The nature and the rate of such transformations have been shown to depend on variables, such as impact velocity and collision frequency that depend, in turn, on the whole dynamics of the system. The characterization of the ball dynamics under different impact conditions is then to be considered a necessary step in order to gain a satisfactory control of the experimental set up. In this paper we investigate the motion of a ball in a milling device. Since the ball motion is governed by impulsive forces acting during each collision, no analytical expression for the complete ball trajectory can be obtained. In addition, mechanical systems exhibiting impacts are strongly nonlinear due to sudden changes of velocities at the instant of impact. Many different types of periodic and chaotic impact motions exist indeed even for simple systems with external periodic excitation forces. We present results of the analysis on the ball trajectory, obtained from a suitable numerical model, under growing degree of impact elasticity. A route to high dimensional chaos is obtained. Crisis and attractors merging are also found

Specificity and entropy reduction in situated referential processing

In situated communication, reference to an entity in the shared visual context can be established using eitheranexpression that conveys precise (minimally specified) or redundant (over-specified) information. There is, however, along-lasting debate in psycholinguistics concerningwhether the latter hinders referential processing. We present evidence from an eyetrackingexperiment recordingfixations as well asthe Index of Cognitive Activity –a novel measure of cognitive workload –supporting the view that over-specifications facilitate processing. We further present originalevidence that, above and beyond the effect of specificity,referring expressions thatuniformly reduce referential entropyalso benefitprocessin

Rational Redundancy in Referring Expressions: Evidence from Event-related Potentials

In referential communication, Grice's Maxim of Quantity is thought to imply that utterances conveying unnecessary information should incur comprehension difficulties. There is, however, considerable evidence that speakers frequently encode redundant information in their referring expressions, raising the question as to whether such overspecifications hinder listeners' processing. Evidence from previous work is inconclusive, and mostly comes from offline studies. In this article, we present two event-related potential (ERP) experiments, investigating the real-time comprehension of referring expressions that contain redundant adjectives in complex visual contexts. Our findings provide support for both Gricean and bounded-rational accounts. We argue that these seemingly incompatible results can be reconciled if common ground is taken into account. We propose a bounded-rational account of overspecification, according to which even redundant words can be beneficial to comprehension to the extent that they facilitate the reduction of listeners' uncertainty regarding the target referent

ERP indices of situated reference in visual contexts

Violations of the maxims of Quantity occur when utterances provide more (over-specified) or less (under-specified) information than strictly required for referent identification. While behavioural datasuggest that under-specified expressions lead to comprehension difficulty and communicative failure, there is no consensus as to whether over-specified expressions are also detrimental to comprehension. In this study we shed light on this debate, providing neurophysiological evidence supporting the view that extra information facilitates comprehension. We further present novel evidence that referential failure due to under-specification is qualitatively different from explicit cases of referential failure, when no matching referential candidate is available in the context

The Argument For: Retaining Income as One of Two Factors in Maine’s School Aid Funding Formula

Brennan and Delogu’s commentary asserts the importance of retaining local household income as a factor in determining school funding formulas in Maine. They note that inclusion of income in school aid equalization formulas has been embraced in over a dozen other states

DFT study of [Pt(Cl)2L] complex (L = rubeanic acid) and its derived compounds with DNA purine bases

In this study, we present a systematic computational investigation on the electronic properties of cisplatin (cis-[Pt(Cl)2(NH3)2] (CP) and complex [Pt(Cl)2L] (1) (L = rubeanic acid) employing all-electron density functional theory. In detail, we analyzed essential molecular properties such as geometrical parameters, ionization energies, electron affinity, highest occupied molecular orbital, and lowest unoccupied molecular orbital energies. Concerning CP, molecule 1 exhibited improved lipophilicity and a pronounced electrophilic property. Furthermore, to investigate and compare the DNA binding capability between CP and molecule 1, we extended the investigation to the guanine and adenine derived complexes, respectively. Complexes of molecule 1 with the adenine and guanine bases followed a similar trend of stability found for CP systems, with the highest affinity found for guanine complexes. Altogether, molecule 1 displayed promising physicochemical and druglikeness features to serve as a starting point for developing a drug-like enough that could be therapeutically useful

Correctional nursing in Liguria, Italy: examining the ethical challenges

Introduction: Correctional nursing can involve significant ethical difficulties. This study examined ethical challenges encountered by correctional nurses in the Italian region of Liguria. Empirical data were analyzed in relation to relevant ethical standards. The former involved a study of 75 nurses and managers in the Ligurian correctional system, while the latter involved an analysis of the Italian Code of Ethics for Nurses and related standards for correctional practice. Methods: Quantitative and qualitative methods were used for the empirical study. Questionnaires were administered to collect data on participants' characteristics and care settings. The Measure of Job Satisfaction (MJS) was also administered. Five focus groups were conducted. Results: Quantitative Data: Respondents identified factors that mostly impacted on recruitment and retention. Unfavourable factors included: structural, organizational, and relational factors. Favourable factors included: nursing consultation, continuing education activities, and peer support. MJS results were equal to 'unsatisfied'. Qualitative Data: five themes were identified through thematic analysis of focus group data: Health needs of incarcerated persons; Negotiation of the boundaries between care and custody; Job satisfaction related to nursing in a correctional setting; Barriers to providing good care; and Security needs. Ten categories of norms were identified in the Code as areas of ethical standards relevant for the empirical data. Conclusions: Our empirical findings demonstrate that these nursing standards can be systematically compromised in correctional settings. Nurses feel compelled to provide ethically-problematic nursing services, with situations of moral distress. This research informs the development of needed policy, educational, and practice changes for nurses in correctional settings