In this study, complex dynamics of Briggs–Rauscher reaction system is investigated analytically and numerically. First, the Briggs–Rauscher reaction system is reduced into a new nonlinear parametric oscillator. The Melnikov method is used to derive the condition of the appearance of horseshoe chaos in the cases ω = Ω and ω ≠ Ω. The performed numerical simulations confirm the obtained analytical predictions. Second, the prediction of coexisting attractors is investigated by solving numerically the new nonlinear parametric ordinary differential equation via the (...) fourth-order Runge–Kutta algorithm. As results, it is found that the new nonlinear chemical system displays various coexisting behaviors of symmetric and asymmetric attractors. In addition, the system presents a rich variety of bifurcations phenomena such as symmetry breaking, symmetry restoring, period doubling, reverse period doubling, period-m bubbles, reverse period-m bubbles, intermittency, and antimonotonicity. On the contrary, emerging chaotic band attractors and period-1, period-3, period-9, and period-m bubbles routes to chaos occur in this system. (shrink)

The statistical properties of a single quantum object and an ensemble of independent such objects are considered in detail for two-level systems. Computer simulations of dynamic zero-point quantum fluctuations for a single quantum object are reported and compared with analytic solutions for the ensemble case.

Introduction While quizzing during informed consent for research to ensure understanding has become commonplace, it is unclear whether the quizzing itself is problematic for potential participants. In this study, we address this issue in a multinational HIV prevention research trial enrolling injection drug users in China and Thailand. Methods Enrolment procedures included an informed consent comprehension quiz. An informed consent survey followed. Results 525 participants completed the informed consent survey (Heng County, China=255, Xinjiang, China=229, Chiang Mai, Thailand=41). Mean age was (...) 33 and mean educational level was 8 yrs. While quizzing was felt to be a good way to determine if a person understands the nature of clinical trial participation (97%) and participants did not generally find the quiz to be problematic, minorities of respondents felt pressured (6%); anxious (5%); bored (5%); minded (5%); and did not find the questions easy (13%). In multivariate analysis, lower educational level was associated with not minding the quizzing (6–10 yrs vs 0–5 yrs: OR=0.27, p=0.03; more than 11 yrs vs 0–5 yrs: OR=0.18, p=0.03). There were also site differences (Heng County vs Xinjiang) in feeling anxious (OR=0.07; p=<0.01), not minding (OR=0.26; p=0.03), being bored (OR=0.25; p=0.01) and not finding the questions easy (OR=0.10; p=<0.01). Conclusions Quizzing during the informed consent process can be problematic for a minority of participants. These problems may be associated with the setting in which research takes place and educational level. Further research is needed to develop, test and implement alternative methods of ensuring comprehension of informed consent. Trial Registration clinicaltrials.gov number NCT00270257. (shrink)

Les concepts de la physique ont été élaborés jusqu'ici par ajustement de la théorie à l'expérience. Désormais l'exploration de la matière nécessite une approche plus fine, où les concepts soient chargés de sens. Ici, les auteurs proposent de fonder la physique sur la "symbiose" entre une logique nouvelle et des principes métaphysiques qui structurent le concept de réalité. Les entités connues de la physique se déduisent directement de ces fondements, d'autres se révèlent et leur détection constitue un nouveau défi pour (...) les expérimentateurs. La microphysique y est dominée par la présence constitutive de non-ordre. Les phénomènes quantiques et l'espace-temps s'en trouvent réinterprétés. Diverses questions très actuelles sont examinées: matière noire, fusion froide, atomes hypercondensés, monopôles magnétiques... Cet ouvrage constitue un bouleversement épistémologique majeur car il fournit un modèle de pensée efficace dont les structures s'appliquent à tous les domaines de la science. (shrink)

The microstructures of cryogenically ball-milled Cu were investigated by high-resolution electron microscopy. It was found that the grain-size reduction is a dislocation-controlled continuous process which consists of the formation of small-angle grain boundaries , a gradual increase in misorientations as a result of accumulation of more dislocations and, finally, the formation of large-angle GBs. The GBs were generally curved, wavy or faceted, and heavily strained, which are typical characteristics of nanostructured materials. In addition, extrinsic dislocations were found in many GBs, (...) indicating that most are in a high-energy non-equilibrium configuration, which is consistent with observations in equal-channel angular pressing processed Cu, Ni, and Al-Mg, repetitive corrugation and straightening processed Cu and room-temperature ball-milled Cu. These results support a still-disputed concept that GBs in nanostructured metals processed by severe plastic deformation are mostly in non-equilibrium states. (shrink)

The following texts and comments are a supplement to ‘Democritus on Politics and the Care of the Soul’, CQ 39 , 307–31 . The Democritean fragments there were quoted only in translation; detailed commentary on them would have taken up too much space and clogged the argument. They make their appearance here in the same order as they did there, preceded by a thumb-nail résumé of that argument and of their place in it. Text, spelling and numbering is that of (...) the standard edition: H. Diels, W. Kranz, Die Fragmente der Vorsokratiker . Reference will also be made to collections by P. Natorp, Die Ethika des Demokritos , S. Y. Luria, Democritea and G. Ibscher, Demócrito y sus sentencias sobre ética y education , as well as to translations by V. E. Alfieri, Gli Atomisti , K. Freeman, Ancilla to the Presocratics and J. Barnes, Early Greek Philosophy. (shrink)

Public policies are designed to have an impact on particular societies, yet policy-oriented computer models and simulations often focus more on articulating the policies to be applied than on realistically rendering the cultural dynamics of the target society. This approach can lead to policy assessments that ignore crucial social contextual factors. For example, by leaving out distinctive moral and normative dimensions of cultural contexts in artificial societies, estimations of downstream policy effectiveness fail to account for dynamics that are fundamental in (...) human life and central to many public policy challenges. In this paper, we supply evidence that incorporating morally salient dimensions of a culture is critically important for producing relevant and accurate evaluations of social policy when using multi-agent artificial intelligence models and simulations. (shrink)

If a hereditary predisposition to colorectal cancer or breast cancer is diagnosed, most guidelines state that clinical geneticists should request index patients to inform their at-risk relatives about the existence of this condition in their family, thus enabling them to consider presymptomatic genetic testing. Those identified as mutation carriers can undertake strategies to reduce their risk of developing the disease or to facilitate early diagnosis. This procedure of informing relatives through the index patient has been criticised, as it results in (...) relatively few requests for genetic testing, conceivably because a certain number of relatives remain uninformed. This pilot study explored attitudes toward informing family members and relevant practices among clinical geneticists. In general, clinical geneticists consider it to be in the interests of family members to be informed and acknowledge that this goal is not accomplished by current procedures. The reasons given for maintaining present practices despite this include clinical ‘mores’, uncertainty about the legal right of doctors to inform family members themselves, and, importantly, a lack of resources. We discuss these reasons from an ethical point of view and conclude that they are partly uninformed and inconsistent. If informing relatives is considered to be in their best interests, clinical geneticists should consider informing relatives themselves. In the common situation in which index patients do not object to informing relatives, no legal obstacles prevent geneticists from doing so. An evaluation of these findings among professionals may lead to a more active approach in clinical practice. (shrink)

Cyclin-dependent kinase 5 has been implicated in Alzheimer's disease pathogenesis. Here, we demonstrate that overexpression of p25, an activator of cdk5, led to increased levels of BACE1 mRNA and protein in vitro and in vivo. A p25/cdk5 responsive region containing multiple sites for signal transducer and activator of transcription was identified in the BACE1 promoter. STAT3 interacts with the BACE1 promoter, and p25-overexpressing mice had elevated levels of pSTAT3 and BACE1, whereas cdk5-deficient mice had reduced levels. Furthermore, mice with a (...) targeted mutation in the STAT3 cdk5 responsive site had lower levels of BACE1. Increased BACE levels in p25 overexpressing mice correlated with enhanced amyloidogenic processing that could be reversed by a cdk5 inhibitor. These data demonstrate a pathway by which p25/cdk5 increases the amyloidogenic processing of APP through STAT3-mediated transcriptional control of BACE1 that could have implications for AD pathogenesis. (shrink)

Background: Expanded newborn screening generates incidental results, notably carrier results. Yet newborn screening programmes typically restrict parental choice regarding receipt of this non-health serving genetic information. Healthcare providers play a key role in educating families or caring for screened infants and have strong beliefs about the management of incidental results. Methods: To inform policy on disclosure of infant sickle cell disorder (SCD) carrier results, a mixed-methods study of healthcare providers was conducted in Ontario, Canada, to understand attitudes regarding result management (...) using a cross-sectional survey (N = 1615) and semistructured interviews (N = 42). Results: Agreement to reasons favouring disclosure of SCD carrier results was high (65.1%–92.7%) and to reasons opposing disclosure was low (4.1%–18.1%). Genetics professionals expressed less support for arguments favouring disclosure (35.3%–78.8%), and more agreement with arguments opposing disclosure (15.7%–51.9%). A slim majority of genetics professionals (51.9%) agreed that a reason to avoid disclosure was the importance of allowing the child to decide to receive results. Qualitatively, there was a perceived “duty” to disclose, that if the clinician possessed the information, the clinician could not withhold it. Discussion: While a majority of respondents perceived a duty to disclose the incidental results of newborn screening, the policy implications of these attitudes are not obvious. In particular, policy must balance descriptive ethics (ie, what providers believe) and normative ethics (ie, what duty-based principles oblige), address dissenting opinion and consider the relevance of moral principles grounded in clinical obligations for public health initiatives. (shrink)

The DSM-IV, like its predecessors, will be a major influence on American psychiatry. As a consequence, continuing analysis of its assumptions is essential. Review of the manuals as well as conceptually-oriented literature on DSM-III, DSM-III-R, and DSM-IV reveals that the authors of these classifications have paid little attention to the explicit and implicit value commitments made by the classifications. The response to DSM criticisms and controversy has often been to incorporate more scientific diversity into the classification, instead of careful inquiry (...) and assessment of the principal values that drive the nosologic process. Implications for psychiatric science and future DSM classifications are discussed. (shrink)

This project was undertaken to develop a telelearning knowledge base aimed at making specialized telelearning knowledge accessible to non-specialized practitioners in the field. The challenge stems from a rationale related to a user-centered approach for the software design process, which is focused on learning in the context of professional practice, the bridge to be built between expert and practitioner knowledge, as well as the knowledge valorization of the latter. In order to take into account users and their situated actions, a (...) usage study was integrated in the analysis phase. This study allows the creation of procedural and contextual telelearning models, and also lists of needs. These results serve as a basis for formulating guidelines for the development of ontologies, for the design of the telelearning knowledge base user interface and telelearning knowledge base environmental description. This paper presents the guidelines and orientations derived from these models. (shrink)

BackgroundECMO is a particularly scarce resource during the COVID-19 pandemic. Its allocation involves ethical considerations that may be different to usual times. There is limited pre-pandemic literature on the ethical factors that ECMO physicians consider during ECMO allocation. During the pandemic, there has been relatively little professional guidance specifically relating to ethics and ECMO allocation; although there has been active ethical debate about allocation of other critical care resources. We report the results of a small international exploratory survey of ECMO (...) clinicians’ views on different patient factors in ECMO decision-making prior to and during the COVID-19 pandemic. We then outline current ethical decision procedures and recommendations for rationing life-sustaining treatment during the COVID-19 pandemic, and examine the extent to which current guidelines for ECMO allocation (and reported practice) adhere to these ethical guidelines and recommendations.MethodsAn online survey was performed with responses recorded between mid May and mid August 2020. Participants (n = 48) were sourced from the ECMOCard study group—an international group of experts (n = 120) taking part in a prospective international study of ECMO and intensive care for patients during the COVID-19 pandemic. The survey compared the extent to which certain ethical factors involved in ECMO resource allocation were considered prior to and during the pandemic.ResultsWhen initiating ECMO during the pandemic, compared to usual times, participants reported giving more ethical weight to the benefit of ECMO to other patients not yet admitted as opposed to those already receiving ECMO, (p < 0.001). If a full unit were referred a good candidate for ECMO, participants were more likely during the pandemic to consider discontinuing ECMO from a current patient with low chance of survival (53% during pandemic vs. 33% prior p = 0.002). If the clinical team recommends that ECMO should cease, but family do not agree, the majority of participants indicated that they would continue treatment, both in usual circumstances (67%) and during the pandemic (56%).ConclusionsWe found differences during the COVID-19 pandemic in prioritisation of several ethical factors in the context of ECMO allocation. The ethical principles prioritised by survey participants were largely consistent with ECMO allocation guidelines, current ethical decision procedures and recommendations for allocation of life-sustaining treatment during the COVID-19 pandemic. (shrink)

This uniquely inspirational and practical book explores human simulation, which is the application of computational modeling and simulation to research subjects in the humanities disciplines. It delves into the fascinating process of collaboration among experts who usually don’t have much to do with one another – computer engineers and humanities scholars – from the perspective of the humanities scholars. It also explains the process of developing models and simulations in these interdisciplinary teams. Each chapter takes the reader on a journey, (...) presenting a specific theory about the human condition, a model of that theory, discussion of its implementation, analysis of its results, and an account of the collaborative experience. Contributing authors with different fields of expertise share how each model was validated, discuss relevant datasets, explain development strategies, and frankly discuss the ups and downs of the process of collaborative development. Readers are given access to the models and will also gain new perspectives from the authors’ findings, experiences, and recommendations. Today we are in the early phases of an information revolution, combining access to vast computing resources, large amounts of human data through social media, and an unprecedented richness of methods and tools to capture, analyze, explore, and test hypotheses and theories of all kinds. Thus, this book’s insights will be valuable not only to students and scholars of humanities subjects, but also to the general reader and researchers from other disciplines who are intrigued by the expansion of the information revolution all the way into the humanities departments of modern universities. (shrink)