THE INTERACTIVE AUTOMATIC SYNDROME DIAGNOSTIC PROGRAM OF DIGESTIVE SYSTEM DISEASES "ELECTRONIC POLICLINIC".

PubMed

Mishlanov, V Yu; Katkova, A V; Dugina, A A; Kuznetzova, V D; Tepanyan, A T; Zhygulev, A N

The aim of the study was to estimate clinical efficiency of the interactive automatic program of digestive system diseases diagnostics "Electronic policlinic". Material was presented by 22 patients with different gastroenterological diseases (duodenal ulcer, chronical gastritis, chronical pancreatitis) and the comparative group consisted of 20 healthy people. The plan of the research included the interactive questionnaire using diagnostic module digestive system diseases of the digestive system of the automated program "Electronic policlinic" (Certificate No. 2012614202 from 12.05.12) posted on the Internet (http://klinikcity.ru). For the purpose of verification of diagnosis patients underwent fibrogastroduodenoscopy, ultrasound examination of abdominal cavity organs, CT scan, sigmoidoscopy, colonoscopy, barium enema. As the result of the study there were showed that interactive automated system was able to reveal 85,7% of patients with chronical gastritis, duodenal ulcer and chronical pancreatitis and 75% of patients with colonopathy. The specify of diagnostic procedure was 80% in the first case and 100% in the second. Prevalence of digestive system diseases basic symptoms was studied too. The conclusion of the study demonstrated interactive questionnaire good ability in preliminary digestive problem patient examination procedure for individual diagnostic plan making.

Can the absence of prejudice be more threatening than its presence? It depends on one's worldview.

PubMed

Townsend, Sarah S M; Major, Brenda; Sawyer, Pamela J; Mendes, Wendy Berry

2010-12-01

The present research used validated cardiovascular measures to examine threat reactions among members of stigmatized groups when interacting with members of nonstigmatized groups who were, or were not, prejudiced against their group. The authors hypothesized that people's beliefs about the fairness of the status system would moderate their experience of threat during intergroup interactions. The authors predicted that for members of stigmatized groups who believe the status system is fair, interacting with a prejudiced partner, compared with interacting with an unprejudiced partner, would disconfirm their worldview and result in greater threat. In contrast, the authors predicted that for members of stigmatized groups who believe the system is unfair, interacting with a prejudiced partner, compared with interacting with an unprejudiced partner, would confirm their worldview and result in less threat. The authors examined these predictions among Latinas interacting with a White female confederate (Study 1) and White females interacting with a White male confederate (Study 2). As predicted, people's beliefs about the fairness of the status system moderated their experiences of threat during intergroup interactions, indicated both by cardiovascular responses and nonverbal behavior. The specific pattern of the moderation differed across the 2 studies. PsycINFO Database Record (c) 2010 APA, all rights reserved.

Integrating Video-Capture Virtual Reality Technology into a Physically Interactive Learning Environment for English Learning

ERIC Educational Resources Information Center

Yang, Jie Chi; Chen, Chih Hung; Jeng, Ming Chang

2010-01-01

The aim of this study is to design and develop a Physically Interactive Learning Environment, the PILE system, by integrating video-capture virtual reality technology into a classroom. The system is designed for elementary school level English classes where students can interact with the system through physical movements. The system is designed to…

Making intelligent systems team players: Additional case studies

NASA Technical Reports Server (NTRS)

Malin, Jane T.; Schreckenghost, Debra L.; Rhoads, Ron W.

1993-01-01

Observations from a case study of intelligent systems are reported as part of a multi-year interdisciplinary effort to provide guidance and assistance for designers of intelligent systems and their user interfaces. A series of studies were conducted to investigate issues in designing intelligent fault management systems in aerospace applications for effective human-computer interaction. The results of the initial study are documented in two NASA technical memoranda: TM 104738 Making Intelligent Systems Team Players: Case Studies and Design Issues, Volumes 1 and 2; and TM 104751, Making Intelligent Systems Team Players: Overview for Designers. The objective of this additional study was to broaden the investigation of human-computer interaction design issues beyond the focus on monitoring and fault detection in the initial study. The results of this second study are documented which is intended as a supplement to the original design guidance documents. These results should be of interest to designers of intelligent systems for use in real-time operations, and to researchers in the areas of human-computer interaction and artificial intelligence.

Social interaction recruits mentalizing and reward systems in middle childhood.

PubMed

Alkire, Diana; Levitas, Daniel; Warnell, Katherine Rice; Redcay, Elizabeth

2018-06-08

Social cognition develops in the context of reciprocal social interaction. However, most neuroimaging studies of mentalizing have used noninteractive tasks that may fail to capture important aspects of real-world mentalizing. In adults, social-interactive context modulates activity in regions linked to social cognition and reward, but few interactive studies have been done with children. The current fMRI study examines children aged 8-12 using a novel paradigm in which children believed they were interacting online with a peer. We compared mental and non-mental state reasoning about a live partner (Peer) versus a story character (Character), testing the effects of mentalizing and social interaction in a 2 × 2 design. Mental versus Non-Mental reasoning engaged regions identified in prior mentalizing studies, including the temporoparietal junction, superior temporal sulcus, and dorsomedial prefrontal cortex. Moreover, peer interaction, even in conditions without explicit mentalizing demands, activated many of the same mentalizing regions. Peer interaction also activated areas outside the traditional mentalizing network, including the reward system. Our results demonstrate that social interaction engages multiple neural systems during middle childhood and contribute further evidence that social-interactive paradigms are needed to fully capture how the brain supports social processing in the real world. © 2018 Wiley Periodicals, Inc.

Biophysical interactions with model lipid membranes: applications in drug discovery and drug delivery

PubMed Central

Peetla, Chiranjeevi; Stine, Andrew; Labhasetwar, Vinod

2009-01-01

The transport of drugs or drug delivery systems across the cell membrane is a complex biological process, often difficult to understand because of its dynamic nature. In this regard, model lipid membranes, which mimic many aspects of cell-membrane lipids, have been very useful in helping investigators to discern the roles of lipids in cellular interactions. One can use drug-lipid interactions to predict pharmacokinetic properties of drugs, such as their transport, biodistribution, accumulation, and hence efficacy. These interactions can also be used to study the mechanisms of transport, based on the structure and hydrophilicity/hydrophobicity of drug molecules. In recent years, model lipid membranes have also been explored to understand their mechanisms of interactions with peptides, polymers, and nanocarriers. These interaction studies can be used to design and develop efficient drug delivery systems. Changes in the lipid composition of cells and tissue in certain disease conditions may alter biophysical interactions, which could be explored to develop target-specific drugs and drug delivery systems. In this review, we discuss different model membranes, drug-lipid interactions and their significance, studies of model membrane interactions with nanocarriers, and how biophysical interaction studies with lipid model membranes could play an important role in drug discovery and drug delivery. PMID:19432455

Analysis of protein interactions within the cytokinin-signaling pathway of Arabidopsis thaliana.

PubMed

Dortay, Hakan; Mehnert, Nijuscha; Bürkle, Lukas; Schmülling, Thomas; Heyl, Alexander

2006-10-01

The signal of the plant hormone cytokinin is perceived by membrane-located sensor histidine kinases and transduced by other members of the plant two-component system. In Arabidopsis thaliana, 28 two-component system proteins (phosphotransmitters and response regulators) act downstream of three receptors, transmitting the signal from the membrane to the nucleus and modulating the cellular response. Although the principal signaling mechanism has been elucidated, redundancy in the system has made it difficult to understand which of the many components interact to control the downstream biological processes. Here, we present a large-scale interaction study comprising most members of the Arabidopsis cytokinin signaling pathway. Using the yeast two-hybrid system, we detected 42 new interactions, of which more than 90% were confirmed by in vitro coaffinity purification. There are distinct patterns of interaction between protein families, but only a few interactions between proteins of the same family. An interaction map of this signaling pathway shows the Arabidopsis histidine phosphotransfer proteins as hubs, which interact with members from all other protein families, mostly in a redundant fashion. Domain-mapping experiments revealed the interaction domains of the proteins of this pathway. Analyses of Arabidopsis histidine phosphotransfer protein 5 mutant proteins showed that the presence of the canonical phospho-accepting histidine residue is not required for the interactions. Interaction of A-type response regulators with Arabidopsis histidine phosphotransfer proteins but not with B-type response regulators suggests that their known activity in feedback regulation may be realized by interfering at the level of Arabidopsis histidine phosphotransfer protein-mediated signaling. This study contributes to our understanding of the protein interactions of the cytokinin-signaling system and provides a framework for further functional studies in planta.

Cerebral-Body Perfusion Model

DTIC Science & Technology

1990-07-01

to simulate flow and pressure interaction between the cerebral and the body systems. its objective is to study the dynamic interaction between the...single model. The objective is to enable the study of the dynamic interaction between these two systems. In this model, relevant parts of the brain and of...34blackout, can also be investigated. For example, the effect can be studied of different inhale/exhale and/or different relative positioning betwoen head-body

From Virtual Environments to Physical Environments: Exploring Interactivity in Ubiquitous-Learning Systems

ERIC Educational Resources Information Center

Peng, Hsinyi; Chou, Chien; Chang, Chun-Yu

2008-01-01

Computing devices and applications are now used beyond the desktop, in diverse environments, and this trend toward ubiquitous computing is evolving. In this study, we re-visit the interactivity concept and its applications for interactive function design in a ubiquitous-learning system (ULS). Further, we compare interactivity dimensions and…

Exploring the roles of interaction and flow in explaining nurses' e-learning acceptance.

PubMed

Cheng, Yung-Ming

2013-01-01

To provide safe and competent patient care, it is very important that medical institutions should provide nurses with continuing education by using appropriate learning methods. As compared to traditional learning, electronic learning (e-learning) is a more flexible method for nurses' in-service learning. Hence, e-learning is expected to play a pivotal role in providing continuing education for nurses. This study's purpose was to explore the role and relevance of interaction factors, intrinsic motivator (i.e., flow), and extrinsic motivators (i.e., perceived usefulness (PU) and perceived ease of use (PEOU)) in explaining nurses' intention to use the e-learning system. Based on the technology acceptance model (TAM) with the flow theory, this study's research model presents three types of interaction factors, learner-system interaction, instructor-learner interaction, and learner-learner interaction to construct an extended TAM to explore nurses' intention to use the e-learning system. Sample data were gathered from nurses at two regional hospitals in Taiwan. A total of 320 questionnaires were distributed, 254 (79.375%) questionnaires were returned. Consequently, 218 usable questionnaires were analyzed in this study, with a usable response rate of 68.125%. First, confirmatory factor analysis was used to develop the measurement model. Second, to explore the causal relationships among all constructs, the structural model for the research model was tested by using structural equation modeling. First, learner-system interaction, instructor-learner interaction, and learner-learner interaction respectively had significant effects on PU, PEOU, and flow. Next, flow had significant effects on PU and PEOU, and PEOU had a significant effect on PU. Finally, the effects of flow, PU, and PEOU on intention to use were significant. Synthetically speaking, learner-system interaction, instructor-learner interaction, and learner-learner interaction can indirectly make significant impacts on nurses' usage intention of the e-learning system via their extrinsic motivators (i.e., PU and PEOU) and intrinsic motivator (i.e., flow). Copyright © 2012 Elsevier Ltd. All rights reserved.

Can the Absence of Prejudice be More Threatening than its Presence? It Depends on one's Worldview

PubMed Central

Townsend, Sarah S. M.; Major, Brenda; Sawyer, Pamela J.; Mendes, Wendy Berry

2010-01-01

The current research used validated cardiovascular measures to examine threat reactions among members of stigmatized groups when interacting with members of nonstigmatized groups who were, or were not, prejudiced against their group. We hypothesized that people's beliefs about the fairness of the status system would moderate their experience of threat during intergroup interactions. We predicted that for members of stigmatized groups who believe the status system is fair, interacting with a prejudiced relative to an unprejudiced partner would disconfirm their worldview and result in greater threat. In contrast, we predicted that for members of stigmatized groups who believe the system is unfair, interacting with a prejudiced relative to an unprejudiced partner would confirm their worldview and result in less threat. We examined these predictions among Latinas interacting with a White female confederate (Study 1) and White females interacting with a White male confederate (Study 2). As predicted, people's beliefs about the fairness of the status system moderated their experiences of threat during intergroup interactions, indicated both by cardiovascular responses and nonverbal behavior. The specific pattern of the moderation differed across the two studies. PMID:21114352

Interaction of dissolution, sorption and biodegradation on transport of BTEX in a saturated groundwater system: Numerical modeling and spatial moment analysis

NASA Astrophysics Data System (ADS)

Valsala, Renu; Govindarajan, Suresh Kumar

2018-06-01

Interaction of various physical, chemical and biological transport processes plays an important role in deciding the fate and migration of contaminants in groundwater systems. In this study, a numerical investigation on the interaction of various transport processes of BTEX in a saturated groundwater system is carried out. In addition, the multi-component dissolution from a residual BTEX source under unsteady flow conditions is incorporated in the modeling framework. The model considers Benzene, Toluene, Ethyl Benzene and Xylene dissolving from the residual BTEX source zone to undergo sorption and aerobic biodegradation within the groundwater aquifer. Spatial concentration profiles of dissolved BTEX components under the interaction of various sorption and biodegradation conditions have been studied. Subsequently, a spatial moment analysis is carried out to analyze the effect of interaction of various transport processes on the total dissolved mass and the mobility of dissolved BTEX components. Results from the present numerical study suggest that the interaction of dissolution, sorption and biodegradation significantly influence the spatial distribution of dissolved BTEX components within the saturated groundwater system. Mobility of dissolved BTEX components is also found to be affected by the interaction of these transport processes.

Structural basis of a rationally rewired protein-protein interface critical to bacterial signaling

PubMed Central

Podgornaia, Anna I.; Casino, Patricia; Marina, Alberto; Laub, Michael T.

2013-01-01

Summary Two-component signal transduction systems typically involve a sensor histidine kinase that specifically phosphorylates a single, cognate response regulator. This protein-protein interaction relies on molecular recognition via a small set of residues in each protein. To better understand how these residues determine the specificity of kinase-substrate interactions, we rationally rewired the interaction interface of a Thermotoga maritima two-component system, HK853-RR468, to match that found in a different two-component system, E. coli PhoR-PhoB. The rewired proteins interacted robustly with each other, but no longer interacted with the parent proteins. Analysis of the crystal structures of the wild-type and mutant protein complexes, along with a systematic mutagenesis study, reveals how individual mutations contribute to the rewiring of interaction specificity. Our approach and conclusions have implications for studies of other protein-protein interactions, protein evolution, and the design of novel protein interfaces. PMID:23954504

Utilizing a Low-Cost, Laser-Driven Interactive System (LaDIS) to Improve Learning in Developing Rural Regions

ERIC Educational Resources Information Center

Liou, Wei-Kai; Chang, Chun-Yen

2014-01-01

This study proposes an innovation Laser-Driven Interactive System (LaDIS), utilizing general IWBs (Interactive Whiteboard) didactics, to support student learning for rural and developing regions. LaDIS is a system made to support traditional classroom practices between an instructor and a group of students. This invention effectively transforms a…

The Effects of Using the Kinect Motion-Sensing Interactive System to Enhance English Learning for Elementary Students

ERIC Educational Resources Information Center

Pan, Wen Fu

2017-01-01

The objective of this study was to test whether the Kinect motion-sensing interactive system (KMIS) enhanced students' English vocabulary learning, while also comparing the system's effectiveness against a traditional computer-mouse interface. Both interfaces utilized an interactive game with a questioning strategy. One-hundred and twenty…

Performance and Norms of Time for Adult Learners Instructed in CPR by an Interactive Videodisc System.

ERIC Educational Resources Information Center

Lyness, Ann L.

A computer system using interactive videodisc was developed and used by the American Heart Association to teach nursing students and others cardiopulmonary resuscitation (CPR). Two studies were made of the use of the system. Between September 1982 and April 1983, 48 participants received CPR instruction by interactive videodisc and 51 by…

Interaction between pancreatic β cell and electromagnetic fields: A systematic study toward finding the natural frequency spectrum of β cell system.

PubMed

Farashi, Sajjad

2017-01-01

Interaction between biological systems and environmental electric or magnetic fields has gained attention during the past few decades. Although there are a lot of studies that have been conducted for investigating such interaction, the reported results are considerably inconsistent. Besides the complexity of biological systems, the important reason for such inconsistent results may arise due to different excitation protocols that have been applied in different experiments. In order to investigate carefully the way that external electric or magnetic fields interact with a biological system, the parameters of excitation, such as intensity or frequency, should be selected purposefully due to the influence of these parameters on the system response. In this study, pancreatic β cell, the main player of blood glucose regulating system, is considered and the study is focused on finding the natural frequency spectrum of the system using modeling approach. Natural frequencies of a system are important characteristics of the system when external excitation is applied. The result of this study can help researchers to select proper frequency parameter for electrical excitation of β cell system. The results show that there are two distinct frequency ranges for natural frequency of β cell system, which consist of extremely low (or near zero) and 100-750 kHz frequency ranges. There are experimental works on β cell exposure to electromagnetic fields that support such finding.

Voice Interactive Analysis System Study. Final Report, August 28, 1978 through March 23, 1979.

ERIC Educational Resources Information Center

Harry, D. P.; And Others

The Voice Interactive Analysis System study continued research and development of the LISTEN real-time, minicomputer based connected speech recognition system, within NAVTRAEQUIPCEN'S program of developing automatic speech technology in support of training. An attempt was made to identify the most effective features detected by the TTI-500 model…

Experimental Models to Study the Role of Microbes in Host-Parasite Interactions.

PubMed

Hahn, Megan A; Dheilly, Nolwenn M

2016-01-01

Until recently, parasitic infections have been primarily studied as interactions between the parasite and the host, leaving out crucial players: microbes. The recent realization that microbes play key roles in the biology of all living organisms is not only challenging our understanding of host-parasite evolution, but it also provides new clues to develop new therapies and remediation strategies. In this paper we provide a review of promising and advanced experimental organismal systems to examine the dynamic of host-parasite-microbe interactions. We address the benefits of developing new experimental models appropriate to this new research area and identify systems that offer the best promises considering the nature of the interactions among hosts, parasites, and microbes. Based on these systems, we identify key criteria for selecting experimental models to elucidate the fundamental principles of these complex webs of interactions. It appears that no model is ideal and that complementary studies should be performed on different systems in order to understand the driving roles of microbes in host and parasite evolution.

The Interaction Systems Generated by the Teacher's Didactic Imprinting

ERIC Educational Resources Information Center

Peralta, Nadia S.; Roselli, Néstor D.

2015-01-01

The current study aimed to identify and analyze the systems of interaction implemented by teachers in university classes, based on their teaching imprints. It focused on the interactions occurred in scholar natural contexts and the construction of knowledge based on said interaction. A form to observe the different behaviors was designed in order…

Diversity in Genetic In Vivo Methods for Protein-Protein Interaction Studies: from the Yeast Two-Hybrid System to the Mammalian Split-Luciferase System

PubMed Central

Stynen, Bram; Tournu, Hélène; Tavernier, Jan

2012-01-01

Summary: The yeast two-hybrid system pioneered the field of in vivo protein-protein interaction methods and undisputedly gave rise to a palette of ingenious techniques that are constantly pushing further the limits of the original method. Sensitivity and selectivity have improved because of various technical tricks and experimental designs. Here we present an exhaustive overview of the genetic approaches available to study in vivo binary protein interactions, based on two-hybrid and protein fragment complementation assays. These methods have been engineered and employed successfully in microorganisms such as Saccharomyces cerevisiae and Escherichia coli, but also in higher eukaryotes. From single binary pairwise interactions to whole-genome interactome mapping, the self-reassembly concept has been employed widely. Innovative studies report the use of proteins such as ubiquitin, dihydrofolate reductase, and adenylate cyclase as reconstituted reporters. Protein fragment complementation assays have extended the possibilities in protein-protein interaction studies, with technologies that enable spatial and temporal analyses of protein complexes. In addition, one-hybrid and three-hybrid systems have broadened the types of interactions that can be studied and the findings that can be obtained. Applications of these technologies are discussed, together with the advantages and limitations of the available assays. PMID:22688816

Many-Body Physics in Long-Range Interacting Quantum Systems

NASA Astrophysics Data System (ADS)

Zhu, Bihui

Ultracold atomic and molecular systems provide a useful platform for understanding quantum many-body physics. Recent progresses in AMO experiments enable access to systems exhibiting long-range interactions, opening a window for exploring the interplay between long-range interactions and dissipation. In this thesis, I develop theoretical approaches to study non-equilibrium dynamics in systems where such interplay is crucial. I first focus on a system of KRb molecules, where dipolar interactions and fast chemical reactions coexist. Using a classical kinetic theory and Monte Carlo methods, I study the evaporative cooling in a quasi-two-dimensional trap, and develop a protocol to reach quantum degeneracy. I also study the case where molecules are loaded into an optical lattice, and show that the strong dissipation induces a quantum Zeno effect, which suppresses the molecule loss. The analysis requires including multiple bands to explain recent experimental measurements, and can be used to determine the molecular filling fraction. I also investigate a system of radiating atoms, which experience long-range elastic and dissipative interactions. I explore the collective behavior of atoms and the role of atomic motion. The model is validated by comparison with a recent light scattering experiment using Sr atoms. I also show that incoherently pumped dipoles can undergo a dynamical phase transition to synchronization, and study its signature in the quantum regime.

Predominant Non-additive Effects of Multiple Stressors on Autotroph C:N:P Ratios Propagate in Freshwater and Marine Food Webs

PubMed Central

Villar-Argaiz, Manuel; Medina-Sánchez, Juan M.; Biddanda, Bopaiah A.; Carrillo, Presentación

2018-01-01

A continuing challenge for scientists is to understand how multiple interactive stressor factors affect biological interactions, and subsequently, ecosystems–in ways not easily predicted by single factor studies. In this review, we have compiled and analyzed available research on how multiple stressor pairs composed of temperature (T), light (L), ultraviolet radiation (UVR), nutrients (Nut), carbon dioxide (CO2), dissolved organic carbon (DOC), and salinity (S) impact the stoichiometry of autotrophs which in turn shapes the nature of their ecological interactions within lower trophic levels in streams, lakes and oceans. Our analysis from 66 studies with 320 observations of 11 stressor pairs, demonstrated that non-additive responses predominate across aquatic ecosystems and their net interactive effect depends on the stressor pair at play. Across systems, there was a prevalence of antagonism in freshwater (60–67% vs. 47% in marine systems) compared to marine systems where synergism was more common (49% vs. 33–40% in freshwaters). While the lack of data impeded comparisons among all of the paired stressors, we found pronounced system differences for the L × Nut interactions. For this interaction, our data for C:P and N:P is consistent with the initial hypothesis that the interaction was primarily synergistic in the oceans, but not for C:N. Our study found a wide range of variability in the net effects of the interactions in freshwater systems, with some observations supporting antagonism, and others synergism. Our results suggest that the nature of the stressor pairs interactions on C:N:P ratios regulates the “continuum” commensalistic-competitive-predatory relationship between algae and bacteria and the food chain efficiency at the algae-herbivore interface. Overall, the scarce number of studies with even more fewer replications in each study that are available for freshwater systems have prevented a more detailed, insightful analysis. Our findings highlighting the preponderance of antagonistic and synergistic effects of stressor interactions in aquatic ecosystems—effects that play key roles in the functioning of feedback loops in the biosphere—also stress the need for further studies evaluating the interactive effects of multiple stressors in a rapidly changing world facing a confluence of tipping points. PMID:29441051

Development of a body motion interactive system with a weight voting mechanism and computer vision technology

NASA Astrophysics Data System (ADS)

Lin, Chern-Sheng; Chen, Chia-Tse; Shei, Hung-Jung; Lay, Yun-Long; Chiu, Chuang-Chien

2012-09-01

This study develops a body motion interactive system with computer vision technology. This application combines interactive games, art performing, and exercise training system. Multiple image processing and computer vision technologies are used in this study. The system can calculate the characteristics of an object color, and then perform color segmentation. When there is a wrong action judgment, the system will avoid the error with a weight voting mechanism, which can set the condition score and weight value for the action judgment, and choose the best action judgment from the weight voting mechanism. Finally, this study estimated the reliability of the system in order to make improvements. The results showed that, this method has good effect on accuracy and stability during operations of the human-machine interface of the sports training system.

Interactive systems design and synthesis of future spacecraft concepts

NASA Technical Reports Server (NTRS)

Wright, R. L.; Deryder, D. D.; Ferebee, M. J., Jr.

1984-01-01

An interactive systems design and synthesis is performed on future spacecraft concepts using the Interactive Design and Evaluation of Advanced spacecraft (IDEAS) computer-aided design and analysis system. The capabilities and advantages of the systems-oriented interactive computer-aided design and analysis system are described. The synthesis of both large antenna and space station concepts, and space station evolutionary growth is demonstrated. The IDEAS program provides the user with both an interactive graphics and an interactive computing capability which consists of over 40 multidisciplinary synthesis and analysis modules. Thus, the user can create, analyze and conduct parametric studies and modify Earth-orbiting spacecraft designs (space stations, large antennas or platforms, and technologically advanced spacecraft) at an interactive terminal with relative ease. The IDEAS approach is useful during the conceptual design phase of advanced space missions when a multiplicity of parameters and concepts must be analyzed and evaluated in a cost-effective and timely manner.

The immune-neuro-endocrine interactions.

PubMed

Tomaszewska, D; Przekop, F

1997-06-01

This article reviews data concerning the interactions between immune, endocrine and neural systems in physiological, pathophysiological and stress conditions in animals and humans. Numerous studies have provided evidence that these systems interact with each other in maintaining homeostasis. This interaction may be classified as follows: immune, endocrine and neural cell products coexist in lymphoid, endocrine and neural tissue. Endocrine and neural mediators modulate immune system activity. Immune, endocrine and neural cells express receptors for cytokines, hormones, neuropeptides and transmitters.

Social interaction in synthetic and natural microbial communities.

PubMed

Xavier, Joao B

2011-04-12

Social interaction among cells is essential for multicellular complexity. But how do molecular networks within individual cells confer the ability to interact? And how do those same networks evolve from the evolutionary conflict between individual- and population-level interests? Recent studies have dissected social interaction at the molecular level by analyzing both synthetic and natural microbial populations. These studies shed new light on the role of population structure for the evolution of cooperative interactions and revealed novel molecular mechanisms that stabilize cooperation among cells. New understanding of populations is changing our view of microbial processes, such as pathogenesis and antibiotic resistance, and suggests new ways to fight infection by exploiting social interaction. The study of social interaction is also challenging established paradigms in cancer evolution and immune system dynamics. Finding similar patterns in such diverse systems suggests that the same 'social interaction motifs' may be general to many cell populations.

Metazoa Ludens: Mixed Reality Interaction and Play Between Humans and Animals

NASA Astrophysics Data System (ADS)

Cheok, Adrian David

Although animals and pets are so important for families and society, in modern urban lifestyles we can spend little time with our animal friends. Interactive media should be aimed to enhance not only human-to-human communication, but also human-to-animal communication. Thus, we promote a new type of inter-species media interaction which allows human users to interact and play with their small pet friends (in this case hamsters) remotely via the Internet through a mixed reality based game system “Metazoa Ludens”. We scientifically examined the effectiveness of this system in a two-pronged approach. Firstly and most importantly, the positive effects to the hamsters were ensured using Body Condition Score study. Secondly, the method of Duncan was used to assess the strength of preference of the hamsters towards Metazoa Ludens. Lastly, the effectiveness of this remote interaction with respect to the human users as a interactive gaming system with their pets/friends (hamsters) was examined based on Csikszentmihalyi's (Beyond boredom and anxiety, 1975) Flow theory. The results of both studies inform of positive remote interaction between human users and their pet friends using our research system. This research is not aimed just at providing specific experimental results on the implemented research system, but is aimed as a wider lesson for human-to-animal interactive media. Thus also the lessons learned are extrapolated and detailed in this chapter as a framework in general for human-to-animal interaction systems.

Conceptual spacecraft systems design and synthesis

NASA Technical Reports Server (NTRS)

Wright, R. L.; Deryder, D. D.; Ferebee, M. J., Jr.

1984-01-01

An interactive systems design and synthesis is performed on future spacecraft concepts using the Interactive Design and Evaluation of Advanced Systems (IDEAS) computer-aided design and analysis system. The capabilities and advantages of the systems-oriented interactive computer-aided design and analysis system are described. The synthesis of both large antenna and space station concepts, and space station evolutionary growth designs is demonstrated. The IDEAS program provides the user with both an interactive graphics and an interactive computing capability which consists of over 40 multidisciplinary synthesis and analysis modules. Thus, the user can create, analyze, and conduct parametric studies and modify earth-orbiting spacecraft designs (space stations, large antennas or platforms, and technologically advanced spacecraft) at an interactive terminal with relative ease. The IDEAS approach is useful during the conceptual design phase of advanced space missions when a multiplicity of parameters and concepts must be analyzed and evaluated in a cost-effective and timely manner.

Choosing to Interact: Exploring the Relationship between Learner Personality, Attitudes, and Tutorial Dialogue Participation

ERIC Educational Resources Information Center

Ezen-Can, Aysu; Boyer, Kristy Elizabeth

2015-01-01

The tremendous effectiveness of intelligent tutoring systems is due in large part to their interactivity. However, when learners are free to choose the extent to which they interact with a tutoring system, not all learners do so actively. This paper examines a study with a natural language tutorial dialogue system for computer science, in which…

Establishment and Usability Evaluation of an Interactive AR Learning System on Conservation of Fish

ERIC Educational Resources Information Center

Lin, Hao-Chiang Koong; Hsieh, Min-Chai; Wang, Cheng-Hung; Sie, Zong-Yuan; Chang, Shei-Hsi

2011-01-01

In this study, we develop an interactive AR Learning System based on Augmented Reality and interactive touch-screen. The learning content knowledge is about conservation of fish in Taiwan. The system combines the game by the concept of AR book which allows children to learn about the importance of conservation of fish. A mechanism is designed to…

Teacher-Child Dyadic Interaction: A Manual for Coding Classroom Behavior. Report Series No. 27.

ERIC Educational Resources Information Center

Brophy, Jere E.; Good, Thomas L.

This manual presents the rationale and coding system for the study of dyadic interaction between teachers and children in classrooms. The introduction notes major differences between this system and others in common use: 1) it is not a universal system that attempts to code all classroom behavior, and 2) the teacher's interactions in his class are…

Robustness of Greenbergerendash Horneendash Zeilinger and W states against Dzyaloshinskii-Moriya interaction

NASA Astrophysics Data System (ADS)

Sharma, Kapil K.; Pandey, S. N.

2016-12-01

In this article, the robustness of tripartite Greenberger-Horne-Zeilinger (GHZ) and W states is investigated against Dzyaloshinskii-Moriya (i.e. DM) interaction. We consider a closed system of three qubits and an environmental qubit. The environmental qubit interacts with any one of the three qubits through DM interaction. The tripartite system is initially prepared in GHZ and W states, respectively. The composite four qubits system evolve with unitary dynamics. We detach the environmental qubit by tracing out from four qubits, and profound impact of DM interaction is studied on the initial entanglement of the system. As a result, we find that the bipartite partitions of W states suffer from entanglement sudden death (i.e. ESD), while tripartite entanglement does not. On the other hand, bipartite partitions and tripartite entanglement in GHZ states do not feel any influence of DM interaction. So, we find that GHZ states have robust character than W states. In this work, we consider generalised GHZ and W states, and three π is used as an entanglement measure. This study can be useful in quantum information processing where unwanted DM interaction takes place.

Trapped atoms along nanophotonic resonators

NASA Astrophysics Data System (ADS)

Fields, Brian; Kim, May; Chang, Tzu-Han; Hung, Chen-Lung

2017-04-01

Many-body systems subject to long-range interactions have remained a very challenging topic experimentally. Ultracold atoms trapped in extreme proximity to the surface of nanophotonic structures provides a dynamic system combining the strong atom-atom interactions mediated by guided mode photons with the exquisite control implemented with trapped atom systems. The hybrid system promises pair-wise tunability of long-range interactions between atomic pseudo spins, allowing studies of quantum magnetism extending far beyond nearest neighbor interactions. In this talk, we will discuss our current status developing high quality nanophotonic ring resonators, engineered on CMOS compatible optical chips with integrated nanostructures that, in combination with a side illuminating beam, can realize stable atom traps approximately 100nm above the surface. We will report on our progress towards loading arrays of cold atoms near the surface of these structures and studying atom-atom interaction mediated by photons with high cooperativity.

Quantum statistics and squeezing for a microwave-driven interacting magnon system.

PubMed

Haghshenasfard, Zahra; Cottam, Michael G

2017-02-01

Theoretical studies are reported for the statistical properties of a microwave-driven interacting magnon system. Both the magnetic dipole-dipole and the exchange interactions are included and the theory is developed for the case of parallel pumping allowing for the inclusion of the nonlinear processes due to the four-magnon interactions. The method of second quantization is used to transform the total Hamiltonian from spin operators to boson creation and annihilation operators. By using the coherent magnon state representation we have studied the magnon occupation number and the statistical behavior of the system. In particular, it is shown that the nonlinearities introduced by the parallel pumping field and the four-magnon interactions lead to non-classical quantum statistical properties of the system, such as magnon squeezing. Also control of the collapse-and-revival phenomena for the time evolution of the average magnon number is demonstrated by varying the parallel pumping amplitude and the four-magnon coupling.

Computer-assisted audiovisual health history self-interviewing. Results of the pilot study of the Hoxworth Quality Donor System.

PubMed

Zuck, T F; Cumming, P D; Wallace, E L

2001-12-01

The safety of blood for transfusion depends, in part, on the reliability of the health history given by volunteer blood donors. To improve reliability, a pilot study evaluated the use of an interactive computer-based audiovisual donor interviewing system at a typical midwestern blood center in the United States. An interactive video screening system was tested in a community donor center environment on 395 volunteer blood donors. Of the donors using the system, 277 completed surveys regarding their acceptance of and opinions about the system. The study showed that an interactive computer-based audiovisual donor screening system was an effective means of conducting the donor health history. The majority of donors found the system understandable and favored the system over a face-to-face interview. Further, most donors indicated that they would be more likely to return if they were to be screened by such a system. Interactive computer-based audiovisual blood donor screening is useful and well accepted by donors; it may prevent a majority of errors and accidents that are reportable to the FDA; and it may contribute to increased safety and availability of the blood supply.

User Interaction Modeling and Profile Extraction in Interactive Systems: A Groupware Application Case Study †

PubMed Central

Tîrnăucă, Cristina; Duque, Rafael; Montaña, José L.

2017-01-01

A relevant goal in human–computer interaction is to produce applications that are easy to use and well-adjusted to their users’ needs. To address this problem it is important to know how users interact with the system. This work constitutes a methodological contribution capable of identifying the context of use in which users perform interactions with a groupware application (synchronous or asynchronous) and provides, using machine learning techniques, generative models of how users behave. Additionally, these models are transformed into a text that describes in natural language the main characteristics of the interaction of the users with the system. PMID:28726762

A Hydroponic Co-cultivation System for Simultaneous and Systematic Analysis of Plant/Microbe Molecular Interactions and Signaling.

PubMed

Nathoo, Naeem; Bernards, Mark A; MacDonald, Jacqueline; Yuan, Ze-Chun

2017-07-22

An experimental design mimicking natural plant-microbe interactions is very important to delineate the complex plant-microbe signaling processes. Arabidopsis thaliana-Agrobacterium tumefaciens provides an excellent model system to study bacterial pathogenesis and plant interactions. Previous studies of plant-Agrobacterium interactions have largely relied on plant cell suspension cultures, the artificial wounding of plants, or the artificial induction of microbial virulence factors or plant defenses by synthetic chemicals. However, these methods are distinct from the natural signaling in planta, where plants and microbes recognize and respond in spatial and temporal manners. This work presents a hydroponic cocultivation system where intact plants are supported by metal mesh screens and cocultivated with Agrobacterium. In this cocultivation system, no synthetic phytohormone or chemical that induces microbial virulence or plant defense is supplemented. The hydroponic cocultivation system closely resembles natural plant-microbe interactions and signaling homeostasis in planta. Plant roots can be separated from the medium containing Agrobacterium, and the signaling and responses of both the plant hosts and the interacting microbes can be investigated simultaneously and systematically. At any given timepoint/interval, plant tissues or bacteria can be harvested separately for various "omics" analyses, demonstrating the power and efficacy of this system. The hydroponic cocultivation system can be easily adapted to study: 1) the reciprocal signaling of diverse plant-microbe systems, 2) signaling between a plant host and multiple microbial species (i.e. microbial consortia or microbiomes), 3) how nutrients and chemicals are implicated in plant-microbe signaling, and 4) how microbes interact with plant hosts and contribute to plant tolerance to biotic or abiotic stresses.

The Contribution of the Dyadic Parent-Child Interaction Coding System (DPICS) Warm-Up Segments in Assessing Parent-Child Interactions

ERIC Educational Resources Information Center

Shanley, Jenelle R.; Niec, Larissa N.

2011-01-01

This study evaluated the inclusion of uncoded segments in the Dyadic Parent-Child Interaction Coding System, an analogue observation of parent-child interactions. The relationships between warm-up and coded segments were assessed, as well as the segments' associations with parent ratings of parent and child behaviors. Sixty-nine non-referred…

INTERACTIONS BETWEEN ORGANIC COMPOUNDS AND CYCLODEXTRIN-CLAY SYSTEMS

EPA Science Inventory

Computational and experimental techniques are combined in order to better understand interactions involving organic compounds and cyclodextrin (CD)-clay systems. CD-clay systems may have great potential in the containment of organic contaminants in the environment. This study w...

Systems Modeling at Multiple Levels of Regulation: Linking Systems and Genetic Networks to Spatially Explicit Plant Populations

PubMed Central

Kitchen, James L.; Allaby, Robin G.

2013-01-01

Selection and adaptation of individuals to their underlying environments are highly dynamical processes, encompassing interactions between the individual and its seasonally changing environment, synergistic or antagonistic interactions between individuals and interactions amongst the regulatory genes within the individual. Plants are useful organisms to study within systems modeling because their sedentary nature simplifies interactions between individuals and the environment, and many important plant processes such as germination or flowering are dependent on annual cycles which can be disrupted by climate behavior. Sedentism makes plants relevant candidates for spatially explicit modeling that is tied in with dynamical environments. We propose that in order to fully understand the complexities behind plant adaptation, a system that couples aspects from systems biology with population and landscape genetics is required. A suitable system could be represented by spatially explicit individual-based models where the virtual individuals are located within time-variable heterogeneous environments and contain mutable regulatory gene networks. These networks could directly interact with the environment, and should provide a useful approach to studying plant adaptation. PMID:27137364

Emulating porphyrins with a rippled multivacancy graphene system

NASA Astrophysics Data System (ADS)

Mombrú, Dominique; Faccio, Ricardo; Mombrú, Alvaro W.

2018-04-01

The interaction between a complex porphyrin-like system formed by an iron atom and multivacant graphene layer and O2, CO and CO2 molecules is studied, using Density Functional Theory (DFT) calculations. The multivacancy graphene system used for this study, consists in the removal of a 1,4-dimethybenzene-like moiety, in a 6 × 6 supercell. This removal and the structural optimization subsequently performed, yield to a biaxial vacancy, where the location of an iron atom embedded in it, lead to a system with resemblance to iron-porphyrin systems. This similar structure could be used to form complexes where gas molecules are allowed to interact with these iron-octavacant graphene systems. The study focuses on the structure of the system and the net magnetic moment for different gas molecules: O2, CO2 and CO. Rippling in the vacant graphene is enhanced through this interaction.

Emergence of structural patterns out of synchronization in networks with competitive interactions

NASA Astrophysics Data System (ADS)

Assenza, Salvatore; Gutiérrez, Ricardo; Gómez-Gardeñes, Jesús; Latora, Vito; Boccaletti, Stefano

2011-09-01

Synchronization is a collective phenomenon occurring in systems of interacting units, and is ubiquitous in nature, society and technology. Recent studies have enlightened the important role played by the interaction topology on the emergence of synchronized states. However, most of these studies neglect that real world systems change their interaction patterns in time. Here, we analyze synchronization features in networks in which structural and dynamical features co-evolve. The feedback of the node dynamics on the interaction pattern is ruled by the competition of two mechanisms: homophily (reinforcing those interactions with other correlated units in the graph) and homeostasis (preserving the value of the input strength received by each unit). The competition between these two adaptive principles leads to the emergence of key structural properties observed in real world networks, such as modular and scale-free structures, together with a striking enhancement of local synchronization in systems with no global order.

Estrogen-Cholinergic Interactions: Implications for Cognitive Aging

PubMed Central

Newhouse, Paul; Dumas, Julie

2015-01-01

While many studies in humans have investigated the effects of estrogen and hormone therapy on cognition, potential neurobiological correlates of these effects have been less well studied. An important site of action for estrogen in the brain is the cholinergic system. Several decades of research support the critical role of CNS cholinergic systems in cognition in humans, particularly in learning and memory formation and attention. In humans, the cholinergic system has been implicated in many aspects of cognition including the partitioning of attentional resources, working memory, inhibition of irrelevant information, and improved performance on effort-demanding tasks. Studies support the hypothesis that estradiol helps to maintain aspects of attention and verbal and visual memory. Such cognitive domains are exactly those modulated by cholinergic systems and extensive basic and preclinical work over the past several decades has clearly shown that basal forebrain cholinergic systems are dependent on estradiol support for adequate functioning. This paper will review recent human studies from our laboratories and others that have extended preclinical research examining estrogen-cholinergic interactions to humans. Studies examined include estradiol and cholinergic antagonist reversal studies in normal older women, examinations of the neural representations of estrogen-cholinergic interactions using functional brain imaging, and studies of the ability of selective estrogen receptor modulators such as tamoxifen to interact with cholinergic-mediated cognitive performance. We also discuss the implications of these studies for the underlying hypotheses of cholinergic-estrogen interactions and cognitive aging, and indications for prophylactic and therapeutic potential that may exploit these effects. PMID:26187712

The next step in health behavior research: the need for ecological moderation analyses - an application to diet and physical activity at childcare.

PubMed

Gubbels, Jessica S; Van Kann, Dave Hh; de Vries, Nanne K; Thijs, Carel; Kremers, Stef Pj

2014-04-17

The ecological perspective holds that human behavior depends on the interaction of different environmental factors and personal characteristics, but it lacks validation and operationalization. In the current paper, an ecological view was adopted to examine the interactive impact of several ecological systems on children's dietary intake and physical activity at childcare or similar facilities. The ecological view was operationalized into three types of interaction: 1) interaction between types of childcare environment (physical, social, political, economic); 2) interaction between micro-systems (the childcare and home environment) in meso-systems; and 3) interaction between childcare environment and child characteristics. The predictive value of each of these interactions was tested based on a systematic review of the literature. Several studies support the hypothesis that the influence of the childcare environment on children's physical activity and diet is moderated by child characteristics (age, gender), but interaction between environmental types as well as between micro-systems is hardly examined in the field of behavioral nutrition and physical activity. Qualitative studies and general child development research provide some valuable insights, but we advocate quantitative research adopting an ecological perspective on environmental influences. Empirical studies operationalizing a true ecological view on diet and physical activity are scarce. Theorizing and assessment of interaction is advocated to become common practice rather than an exception in behavioral nutrition and physical activity research, in order to move the field forward.

The next step in health behavior research: the need for ecological moderation analyses - an application to diet and physical activity at childcare

PubMed Central

2014-01-01

Background The ecological perspective holds that human behavior depends on the interaction of different environmental factors and personal characteristics, but it lacks validation and operationalization. In the current paper, an ecological view was adopted to examine the interactive impact of several ecological systems on children’s dietary intake and physical activity at childcare or similar facilities. The ecological view was operationalized into three types of interaction: 1) interaction between types of childcare environment (physical, social, political, economic); 2) interaction between micro-systems (the childcare and home environment) in meso-systems; and 3) interaction between childcare environment and child characteristics. The predictive value of each of these interactions was tested based on a systematic review of the literature. Discussion Several studies support the hypothesis that the influence of the childcare environment on children’s physical activity and diet is moderated by child characteristics (age, gender), but interaction between environmental types as well as between micro-systems is hardly examined in the field of behavioral nutrition and physical activity. Qualitative studies and general child development research provide some valuable insights, but we advocate quantitative research adopting an ecological perspective on environmental influences. Summary Empirical studies operationalizing a true ecological view on diet and physical activity are scarce. Theorizing and assessment of interaction is advocated to become common practice rather than an exception in behavioral nutrition and physical activity research, in order to move the field forward. PMID:24742167

How Information Visualization Systems Change Users' Understandings of Complex Data

ERIC Educational Resources Information Center

Allendoerfer, Kenneth Robert

2009-01-01

User-centered evaluations of information systems often focus on the usability of the system rather its usefulness. This study examined how a using an interactive knowledge-domain visualization (KDV) system affected users' understanding of a domain. Interactive KDVs allow users to create graphical representations of domains that depict important…

Development of the engineering design integration (EDIN) system: A computer aided design development

NASA Technical Reports Server (NTRS)

Glatt, C. R.; Hirsch, G. N.

1977-01-01

The EDIN (Engineering Design Integration) System which provides a collection of hardware and software, enabling the engineer to perform man-in-the-loop interactive evaluation of aerospace vehicle concepts, was considered. Study efforts were concentrated in the following areas: (1) integration of hardware with the Univac Exec 8 System; (2) development of interactive software for the EDIN System; (3) upgrading of the EDIN technology module library to an interactive status; (4) verification of the soundness of the developing EDIN System; (5) support of NASA in design analysis studies using the EDIN System; (6) provide training and documentation in the use of the EDIN System; and (7) provide an implementation plan for the next phase of development and recommendations for meeting long range objectives.

Spacelab user interaction

NASA Technical Reports Server (NTRS)

1975-01-01

The results of the third and final phase of a study undertaken to define means of optimizing the Spacelab experiment data system by interactively manipulating the flow of data were presented. A number of payload applicable interactive techniques and an integrated interaction system for each of two possible payloads are described. These interaction systems have been functionally defined and are accompanied with block diagrams, hardware specifications, software sizing and speed requirements, operational procedures and cost/benefits analysis data for both onboard and ground based system elements. It is shown that accrued benefits are attributable to a reduction in data processing costs obtained by, generally, a considerable reduction in the quantity of data that might otherwise be generated without interaction. One other additional anticipated benefit includes the increased scientific value obtained by the quicker return of all useful data.

The cation-π interaction.

PubMed

Dougherty, Dennis A

2013-04-16

The chemistry community now recognizes the cation-π interaction as a major force for molecular recognition, joining the hydrophobic effect, the hydrogen bond, and the ion pair in determining macromolecular structure and drug-receptor interactions. This Account provides the author's perspective on the intellectual origins and fundamental nature of the cation-π interaction. Early studies on cyclophanes established that water-soluble, cationic molecules would forego aqueous solvation to enter a hydrophobic cavity if that cavity was lined with π systems. Important gas phase studies established the fundamental nature of the cation-π interaction. The strength of the cation-π interaction (Li(+) binds to benzene with 38 kcal/mol of binding energy; NH4(+) with 19 kcal/mol) distinguishes it from the weaker polar-π interactions observed in the benzene dimer or water-benzene complexes. In addition to the substantial intrinsic strength of the cation-π interaction in gas phase studies, the cation-π interaction remains energetically significant in aqueous media and under biological conditions. Many studies have shown that cation-π interactions can enhance binding energies by 2-5 kcal/mol, making them competitive with hydrogen bonds and ion pairs in drug-receptor and protein-protein interactions. As with other noncovalent interactions involving aromatic systems, the cation-π interaction includes a substantial electrostatic component. The six (four) C(δ-)-H(δ+) bond dipoles of a molecule like benzene (ethylene) combine to produce a region of negative electrostatic potential on the face of the π system. Simple electrostatics facilitate a natural attraction of cations to the surface. The trend for (gas phase) binding energies is Li(+) > Na(+) > K(+) > Rb(+): as the ion gets larger the charge is dispersed over a larger sphere and binding interactions weaken, a classical electrostatic effect. On other hand, polarizability does not define these interactions. Cyclohexane is more polarizable than benzene but a decidedly poorer cation binder. Many studies have documented cation-π interactions in protein structures, where lysine or arginine side chains interact with phenylalanine, tyrosine, or tryptophan. In addition, countless studies have established the importance of the cation-π interaction in a range of biological processes. Our work has focused on molecular neurobiology, and we have shown that neurotransmitters generally use a cation-π interaction to bind to their receptors. We have also shown that many drug-receptor interactions involve cation-π interactions. A cation-π interaction plays a critical role in the binding of nicotine to ACh receptors in the brain, an especially significant case. Other researchers have established important cation-π interactions in the recognition of the "histone code," in terpene biosynthesis, in chemical catalysis, and in many other systems.

The Cation-π Interaction

PubMed Central

DOUGHERTY, DENNIS A.

2014-01-01

CONSPECTUS The chemistry community now recognizes the cation-π interaction as a major force for molecular recognition, joining the hydrophobic effect, the hydrogen bond, and the ion pair in determining macromolecular structure and drug-receptor interactions. This Account provides the author’s perspective on the intellectual origins and fundamental nature of the cation-π interaction. Early studies on cyclophanes established that water-soluble, cationic molecules would forgo aqueous solvation to enter a hydrophobic cavity if that cavity was lined with π systems. Important gas phase studies established the fundamental nature of the cation-π interaction. The strength of the cation-π interaction – Li+ binds to benzene with 38 kcal/mol of binding energy; NH4+ with 19 kcal/mol– distinguishes it from the weaker polar-π interactions observed in the benzene dimer or water-benzene complexes. In addition to the substantial intrinsic strength of the cation-π interaction in gas phase studies, the cation-π interaction remains energetically significant in aqueous media and under biological conditions. Many studies have shown that cation-π interactions can enhance binding energies by 2 – 5 kcal/mol, making them competitive with hydrogen bonds and ion pairs in drug-receptor and protein-protein interactions. As with other noncovalent interactions involving aromatic systems, the cation-π interaction includes a substantial electrostatic component. The six (four) Cδ−–Hδ+ bond dipoles of a molecule like benzene (ethylene) combine to produce a region of negative electrostatic potential on the face of the π system. Simple electrostatics facilitate a natural attraction of cations to the surface. The trend for (gas phase) binding energies is Li+>Na+>K+>Rb+: as the ion gets larger the charge is dispersed over a larger sphere and binding interactions weaken, a classical electrostatic effect. On other hand, polarizability does not define these interactions. Cyclohexane is more polarizable than benzene, but a decidedly poorer cation binder. Many studies have documented cation-π interactions in protein structures, where Lys or Arg side chains interact with Phe, Tyr, or Trp. In addition, countless studies have established the importance of cation-π interaction in a range of biological processes. Our work has focused on molecular neurobiology, and we have shown that neurotransmitters generally use a cation-π interaction to bind to their receptors. We have also shown that many drug-receptor interactions involve cation-π interactions. A cation-π interaction plays a critical role in the binding of nicotine to ACh receptors in the brain, an especially significant case. Other researchers have established important cation-π interactions in the recognition of the “histone code,” in terpene biosynthesis, in chemical catalysis, and in many other systems. PMID:23214924

Genetic background effects in quantitative genetics: gene-by-system interactions.

PubMed

Sardi, Maria; Gasch, Audrey P

2018-04-11

Proper cell function depends on networks of proteins that interact physically and functionally to carry out physiological processes. Thus, it seems logical that the impact of sequence variation in one protein could be significantly influenced by genetic variants at other loci in a genome. Nonetheless, the importance of such genetic interactions, known as epistasis, in explaining phenotypic variation remains a matter of debate in genetics. Recent work from our lab revealed that genes implicated from an association study of toxin tolerance in Saccharomyces cerevisiae show extensive interactions with the genetic background: most implicated genes, regardless of allele, are important for toxin tolerance in only one of two tested strains. The prevalence of background effects in our study adds to other reports of widespread genetic-background interactions in model organisms. We suggest that these effects represent many-way interactions with myriad features of the cellular system that vary across classes of individuals. Such gene-by-system interactions may influence diverse traits and require new modeling approaches to accurately represent genotype-phenotype relationships across individuals.

Nonconventional screening of the Coulomb interaction in FexOy clusters: An ab initio study

NASA Astrophysics Data System (ADS)

Peters, L.; Şaşıoǧlu, E.; Rossen, S.; Friedrich, C.; Blügel, S.; Katsnelson, M. I.

2017-04-01

From microscopic point-dipole model calculations of the screening of the Coulomb interaction in nonpolar systems by polarizable atoms, it is known that screening strongly depends on dimensionality. For example, in one-dimensional systems, the short-range interaction is screened, while the long-range interaction is antiscreened. This antiscreening is also observed in some zero-dimensional structures, i.e., molecular systems. By means of ab initio calculations in conjunction with the random-phase approximation (RPA) within the FLAPW method, we study screening of the Coulomb interaction in FexOy clusters. For completeness, these results are compared with their bulk counterpart magnetite. It appears that the on-site Coulomb interaction is very well screened both in the clusters and bulk. On the other hand, for the intersite Coulomb interaction, the important observation is made that it is almost constant throughout the clusters, while for the bulk it is almost completely screened. More precisely and interestingly, in the clusters antiscreening is observed by means of ab initio calculations.

Mathematical approach to nonlocal interactions using a reaction-diffusion system.

PubMed

Tanaka, Yoshitaro; Yamamoto, Hiroko; Ninomiya, Hirokazu

2017-06-01

In recent years, spatial long range interactions during developmental processes have been introduced as a result of the integration of microscopic information, such as molecular events and signaling networks. They are often called nonlocal interactions. If the profile of a nonlocal interaction is determined by experiments, we can easily investigate how patterns generate by numerical simulations without detailed microscopic events. Thus, nonlocal interactions are useful tools to understand complex biosystems. However, nonlocal interactions are often inconvenient for observing specific mechanisms because of the integration of information. Accordingly, we proposed a new method that could convert nonlocal interactions into a reaction-diffusion system with auxiliary unknown variables. In this review, by introducing biological and mathematical studies related to nonlocal interactions, we will present the heuristic understanding of nonlocal interactions using a reaction-diffusion system. © 2017 Japanese Society of Developmental Biologists.

An Empirical Validation of a Dynamic Systems Model of Interaction: Do Children of Different Sociometric Statuses Differ in Their Dyadic Play?

ERIC Educational Resources Information Center

Steenbeek, Henderien; van Geert, Paul

2008-01-01

Studying short-term dynamic processes and change mechanisms in interaction yields important knowledge that contributes to understanding long-term social development of children. In order to get a grip on this short-term dynamics of interaction processes, the authors made a dynamic systems model of dyadic interaction of children during one play…

Design of a Gaze-Sensitive Virtual Social Interactive System for Children With Autism

PubMed Central

Lahiri, Uttama; Warren, Zachary; Sarkar, Nilanjan

2013-01-01

Impairments in social communication skills are thought to be core deficits in children with autism spectrum disorder (ASD). In recent years, several assistive technologies, particularly Virtual Reality (VR), have been investigated to promote social interactions in this population. It is well known that children with ASD demonstrate atypical viewing patterns during social interactions and thus monitoring eye-gaze can be valuable to design intervention strategies. While several studies have used eye-tracking technology to monitor eye-gaze for offline analysis, there exists no real-time system that can monitor eye-gaze dynamically and provide individualized feedback. Given the promise of VR-based social interaction and the usefulness of monitoring eye-gaze in real-time, a novel VR-based dynamic eye-tracking system is developed in this work. This system, called Virtual Interactive system with Gaze-sensitive Adaptive Response Technology (VIGART), is capable of delivering individualized feedback based on a child’s dynamic gaze patterns during VR-based interaction. Results from a usability study with six adolescents with ASD are presented that examines the acceptability and usefulness of VIGART. The results in terms of improvement in behavioral viewing and changes in relevant eye physiological indexes of participants while interacting with VIGART indicate the potential of this novel technology. PMID:21609889

Design of a gaze-sensitive virtual social interactive system for children with autism.

PubMed

Lahiri, Uttama; Warren, Zachary; Sarkar, Nilanjan

2011-08-01

Impairments in social communication skills are thought to be core deficits in children with autism spectrum disorder (ASD). In recent years, several assistive technologies, particularly Virtual Reality (VR), have been investigated to promote social interactions in this population. It is well known that children with ASD demonstrate atypical viewing patterns during social interactions and thus monitoring eye-gaze can be valuable to design intervention strategies. While several studies have used eye-tracking technology to monitor eye-gaze for offline analysis, there exists no real-time system that can monitor eye-gaze dynamically and provide individualized feedback. Given the promise of VR-based social interaction and the usefulness of monitoring eye-gaze in real-time, a novel VR-based dynamic eye-tracking system is developed in this work. This system, called Virtual Interactive system with Gaze-sensitive Adaptive Response Technology (VIGART), is capable of delivering individualized feedback based on a child's dynamic gaze patterns during VR-based interaction. Results from a usability study with six adolescents with ASD are presented that examines the acceptability and usefulness of VIGART. The results in terms of improvement in behavioral viewing and changes in relevant eye physiological indexes of participants while interacting with VIGART indicate the potential of this novel technology. © 2011 IEEE

Nonadiabatic tapered optical fiber sensor for measuring interaction nicotine with DNA

NASA Astrophysics Data System (ADS)

Zibaii, M. I.; Latifi, H.; Pourbeyram, H.; Gholami, M.; Taghipour, Z.; Saeedian, Z.; Hosseini, S. M.

2011-05-01

A nonadiabatic tapered optical fiber sensor was utilized for studying of bimolecular interactions including DNA-DNA and DNA-Drug interaction. This work presents a simple evanescent wave sensing system based on an interferometric approach, suitable to meet the requirements of lable-free sensor systems for detecting biomolecular interactions. We have demonstrated the measuring refractive index and the real time detection of interactions between biomolecules. Furthermore basic experiments were carried out, for detecting the hybridization of 25-mer DNA with an immobilized counterpart on the surface. The overall shift after the successful DNA hybridization was 9.5 nm. In this work, a new approach for studying DNA-drug interactions was successfully tested. Nicotine as a carcinogenic compound in cigarette smoke plays an important role in interaction with DNA. Different concentrations of nicotine were applied to observe the Longmuir interaction with DNA.

Dual Logic and Cerebral Coordinates for Reciprocal Interaction in Eye Contact

PubMed Central

Lee, Ray F.

2015-01-01

In order to scientifically study the human brain’s response to face-to-face social interaction, the scientific method itself needs to be reconsidered so that both quantitative observation and symbolic reasoning can be adapted to the situation where the observer is also observed. In light of the recent development of dyadic fMRI which can directly observe dyadic brain interacting in one MRI scanner, this paper aims to establish a new form of logic, dual logic, which provides a theoretical platform for deductive reasoning in a complementary dual system with emergence mechanism. Applying the dual logic in the dfMRI experimental design and data analysis, the exogenous and endogenous dual systems in the BOLD responses can be identified; the non-reciprocal responses in the dual system can be suppressed; a cerebral coordinate for reciprocal interaction can be generated. Elucidated by dual logic deductions, the cerebral coordinate for reciprocal interaction suggests: the exogenous and endogenous systems consist of the empathy network and the mentalization network respectively; the default-mode network emerges from the resting state to activation in the endogenous system during reciprocal interaction; the cingulate plays an essential role in the emergence from the exogenous system to the endogenous system. Overall, the dual logic deductions are supported by the dfMRI experimental results and are consistent with current literature. Both the theoretical framework and experimental method set the stage to formally apply the scientific method in studying complex social interaction. PMID:25885446

Vehicle systems: coupled and interactive dynamics analysis

NASA Astrophysics Data System (ADS)

Vantsevich, Vladimir V.

2014-11-01

This article formulates a new direction in vehicle dynamics, described as coupled and interactive vehicle system dynamics. Formalised procedures and analysis of case studies are presented. An analytical consideration, which explains the physics of coupled system dynamics and its consequences for dynamics of a vehicle, is given for several sets of systems including: (i) driveline and suspension of a 6×6 truck, (ii) a brake mechanism and a limited slip differential of a drive axle and (iii) a 4×4 vehicle steering system and driveline system. The article introduces a formal procedure to turn coupled system dynamics into interactive dynamics of systems. A new research direction in interactive dynamics of an active steering and a hybrid-electric power transmitting unit is presented and analysed to control power distribution between the drive axles of a 4×4 vehicle. A control strategy integrates energy efficiency and lateral dynamics by decoupling dynamics of the two systems thus forming their interactive dynamics.

Adapting the Structural Family Systems Rating to Assess the Patterns of Interaction in Families of Dementia Caregivers

ERIC Educational Resources Information Center

Mitrani, Victoria B.; Feaster, Daniel J.; McCabe, Brian E.; Czaja, Sara J.; Szapocznik, Jose

2005-01-01

Purpose: This study adapted the Structural Family Systems Ratings (SFSR), an observational measure of family interactions, for dementia caregivers. This article presents the development of the SFSR-Dementia Caregiver adaptation (SFSR-DC) and examines relationships between specific family-interaction patterns and caregiver distress. Design and…

Renyi entanglement entropy of interacting fermions calculated using the continuous-time quantum Monte Carlo method.

PubMed

Wang, Lei; Troyer, Matthias

2014-09-12

We present a new algorithm for calculating the Renyi entanglement entropy of interacting fermions using the continuous-time quantum Monte Carlo method. The algorithm only samples the interaction correction of the entanglement entropy, which by design ensures the efficient calculation of weakly interacting systems. Combined with Monte Carlo reweighting, the algorithm also performs well for systems with strong interactions. We demonstrate the potential of this method by studying the quantum entanglement signatures of the charge-density-wave transition of interacting fermions on a square lattice.

A Case Study: Implementing an Interactive Video Instruction System in Teaching Electronics and Industrial Maintenance.

ERIC Educational Resources Information Center

Shipe, Ron; And Others

A study examined the development and implementation of an interactive video instruction system for teaching electronics and industrial maintenance at the University of Tennessee. The specific purposes of the study were to document unusual problems that may be encountered when this new technology is implemented, suggest corrective actions, and…

A spin rotator model for Heisenberg helimagnet

NASA Astrophysics Data System (ADS)

Felcy, A. Ludvin; Latha, M. M.

2018-02-01

We study the dynamics of a helimagnetic spin system by proposing a spin rotator model taking into account bilinear, twist interplane and anisotropic interactions in the continuum limit. The dynamical equations of motion are obtained and studied numerically. The influence of different types of inhomogeneities is also analysed. Similar studies are carried out for the system including biquadratic type interactions.

Local versus global interactions in nonequilibrium transitions: A model of social dynamics

NASA Astrophysics Data System (ADS)

González-Avella, J. C.; Eguíluz, V. M.; Cosenza, M. G.; Klemm, K.; Herrera, J. L.; San Miguel, M.

2006-04-01

A nonequilibrium system of locally interacting elements in a lattice with an absorbing order-disorder phase transition is studied under the effect of additional interacting fields. These fields are shown to produce interesting effects in the collective behavior of this system. Both for autonomous and external fields, disorder grows in the system when the probability of the elements to interact with the field is increased. There exists a threshold value of this probability beyond which the system is always disordered. The domain of parameters of the ordered regime is larger for nonuniform local fields than for spatially uniform fields. However, the zero field limit is discontinous. In the limit of vanishingly small probability of interaction with the field, autonomous or external fields are able to order a system that would fall in a disordered phase under local interactions of the elements alone. We consider different types of fields which are interpreted as forms of mass media acting on a social system in the context of Axelrod’s model for cultural dissemination.

Local versus global interactions in nonequilibrium transitions: A model of social dynamics.

PubMed

González-Avella, J C; Eguíluz, V M; Cosenza, M G; Klemm, K; Herrera, J L; San Miguel, M

2006-04-01

A nonequilibrium system of locally interacting elements in a lattice with an absorbing order-disorder phase transition is studied under the effect of additional interacting fields. These fields are shown to produce interesting effects in the collective behavior of this system. Both for autonomous and external fields, disorder grows in the system when the probability of the elements to interact with the field is increased. There exists a threshold value of this probability beyond which the system is always disordered. The domain of parameters of the ordered regime is larger for nonuniform local fields than for spatially uniform fields. However, the zero field limit is discontinous. In the limit of vanishingly small probability of interaction with the field, autonomous or external fields are able to order a system that would fall in a disordered phase under local interactions of the elements alone. We consider different types of fields which are interpreted as forms of mass media acting on a social system in the context of Axelrod's model for cultural dissemination.

Learning with Interactive Computer Graphics in the Undergraduate Neuroscience Classroom

ERIC Educational Resources Information Center

Pani, John R.; Chariker, Julia H.; Naaz, Farah; Mattingly, William; Roberts, Joshua; Sephton, Sandra E.

2014-01-01

Instruction of neuroanatomy depends on graphical representation and extended self-study. As a consequence, computer-based learning environments that incorporate interactive graphics should facilitate instruction in this area. The present study evaluated such a system in the undergraduate neuroscience classroom. The system used the method of…

An Interactive Model for Studying Student Retention. AIR 1990 Annual Forum Paper.

ERIC Educational Resources Information Center

Glover, Robert H.; Wilcox, Jerry

A design for improving the quality of information available for continuous operational study of student retention at the University of Hartford in Connecticut was examined involving a microcomputer based decision support system for student retention research. The system, an interactive modeling approach to conduct longitudinal and comparative…

Aesthetics, Usefulness and Performance in User--Search-Engine Interaction

ERIC Educational Resources Information Center

Katz, Adi

2010-01-01

Issues of visual appeal have become an integral part of designing interactive systems. Interface aesthetics may form users' attitudes towards computer applications and information technology. Aesthetics can affect user satisfaction, and influence their willingness to buy or adopt a system. This study follows previous studies that found that users…

Visual interaction: models, systems, prototypes. The Pictorial Computing Laboratory at the University of Rome La Sapienza.

PubMed

Bottoni, Paolo; Cinque, Luigi; De Marsico, Maria; Levialdi, Stefano; Panizzi, Emanuele

2006-06-01

This paper reports on the research activities performed by the Pictorial Computing Laboratory at the University of Rome, La Sapienza, during the last 5 years. Such work, essentially is based on the study of humancomputer interaction, spans from metamodels of interaction down to prototypes of interactive systems for both synchronous multimedia communication and groupwork, annotation systems for web pages, also encompassing theoretical and practical issues of visual languages and environments also including pattern recognition algorithms. Some applications are also considered like e-learning and collaborative work.

Detection of plum pox potyviral protein-protein interactions in planta using an optimized mRFP-based bimolecular fluorescence complementation system.

PubMed

Zilian, Eva; Maiss, Edgar

2011-12-01

In previous studies, protein interaction maps of different potyviruses have been generated using yeast two-hybrid (YTH) systems, and these maps have demonstrated a high diversity of interactions of potyviral proteins. Using an optimized bimolecular fluorescence complementation (BiFC) system, a complete interaction matrix for proteins of a potyvirus was developed for the first time under in planta conditions with ten proteins from plum pox virus (PPV). In total, 52 of 100 possible interactions were detected, including the self-interactions of CI, 6K2, VPg, NIa-Pro, NIb and CP, which is more interactions than have ever been detected for any other potyvirus in a YTH approach. Moreover, the BiFC system was shown to be able to localize the protein interactions, which was typified for the protein self-interactions indicated above. Additionally, experiments were carried out with the P3N-PIPO protein, revealing an interaction with CI but not with CP and supporting the involvement of P3N-PIPO in the cell-to-cell movement of potyviruses. No self-interaction of the PPV helper component-proteinase (HC-Pro) was detected using BiFC in planta. Therefore, additional experiments with turnip mosaic virus (TuMV) HC-Pro, PPV_HC-Pro and their mutants were conducted. The self-interaction of TuMV_HCpro, as recently demonstrated, and the self-interaction of the TuMV_ and PPV_HC-Pro mutants were shown by BiFC in planta, indicating that HC-Pro self-interactions may be species-specific. BiFC is a very useful and reliable method for the detection and localization of protein interactions in planta, thus enabling investigations under more natural conditions than studies in yeast cells.

Simple and efficient machine learning frameworks for identifying protein-protein interaction relevant articles and experimental methods used to study the interactions.

PubMed

Agarwal, Shashank; Liu, Feifan; Yu, Hong

2011-10-03

Protein-protein interaction (PPI) is an important biomedical phenomenon. Automatically detecting PPI-relevant articles and identifying methods that are used to study PPI are important text mining tasks. In this study, we have explored domain independent features to develop two open source machine learning frameworks. One performs binary classification to determine whether the given article is PPI relevant or not, named "Simple Classifier", and the other one maps the PPI relevant articles with corresponding interaction method nodes in a standardized PSI-MI (Proteomics Standards Initiative-Molecular Interactions) ontology, named "OntoNorm". We evaluated our system in the context of BioCreative challenge competition using the standardized data set. Our systems are amongst the top systems reported by the organizers, attaining 60.8% F1-score for identifying relevant documents, and 52.3% F1-score for mapping articles to interaction method ontology. Our results show that domain-independent machine learning frameworks can perform competitively well at the tasks of detecting PPI relevant articles and identifying the methods that were used to study the interaction in such articles. Simple Classifier is available at http://sourceforge.net/p/simpleclassify/home/ and OntoNorm at http://sourceforge.net/p/ontonorm/home/.

Technology Adoption: an Interaction Perspective

NASA Astrophysics Data System (ADS)

Sitorus, Hotna M.; Govindaraju, Rajesri; Wiratmadja, I. I.; Sudirman, Iman

2016-02-01

The success of a new technology depends on how well it is accepted by its intended users. Many technologies face the problem of low adoption rate, despite the benefits. An understanding of what makes people accept or reject a new technology can help speed up the adoption rate. This paper presents a framework for technology adoption based on an interactive perspective, resulting from a literature study on technology adoption. In studying technology adoption, it is necessary to consider the interactions among elements involved in the system, for these interactions may generate new characteristics or new relationships. The interactions among elements in a system adoption have not received sufficient consideration in previous studies of technology adoption. Based on the proposed interaction perspective, technology adoption is elaborated by examining interactions among the individual (i.e. the user or prospective user), the technology, the task and the environment. The framework is formulated by adopting several theories, including Perceived Characteristics of Innovating, Diffusion of Innovation Theory, Technology Acceptance Model, Task-Technology Fit and usability theory. The proposed framework is illustrated in the context of mobile banking adoption. It is aimed to offer a better understanding of determinants of technology adoption in various contexts, including technology in manufacturing systems.

In Situ Proximity Ligation Assays Indicate That Hemochromatosis Proteins Hfe and Transferrin Receptor 2 (Tfr2) Do Not Interact

PubMed Central

Rishi, Gautam; Crampton, Emily M.; Wallace, Daniel F.; Subramaniam, V. Nathan

2013-01-01

The hemochromatosis associated proteins HFE and Transferrin Receptor 2 (TFR2) have been shown to be important for the proper regulation of hepcidin. A number of in vitro studies using transient overexpression systems have suggested that an interaction between HFE and TFR2 is required for the regulation of hepcidin. This model of iron sensing which centers upon the requirement for an interaction between HFE and TFR2 has recently been questioned with in vivo studies in mice from our laboratory and others which suggest that Hfe and Tfr2 can regulate hepcidin independently of each other. To re-examine the postulated interaction between Hfe and Tfr2 we developed a novel expression system in which both proteins are stably co-expressed and used the proximity ligation assay to examine the interactions between Hfe, Tfr1 and Tfr2 at a cellular level. We were able to detect the previously described interaction between Hfe and Tfr1, and heterodimers between Tfr1 and Tfr2; however no interaction between Hfe and Tfr2 was observed in our system. The results from this study indicate that Hfe and Tfr2 do not interact with each other when they are stably expressed at similar levels. Furthermore, these results support in vivo studies which suggest that Hfe and Tfr2 can independently regulate hepcidin. PMID:24155934

Metal-atom Interactions and Clustering in Organic Semiconductor Systems

NASA Astrophysics Data System (ADS)

Tomita, Yoko; Park, Tea-uk; Nakayama, Takashi

2017-07-01

The interatomic interactions and clustering of metal atoms have been studied by first-principles calculations in graphene, pentacene, and polyacetylene as representative organic systems. It is shown that long-range repulsive Coulomb interaction appears between metal atoms with small electronegativity such as Al due to their ionization on host organic molecules, inducing their scattered distribution in organic systems. On the other hand, metal atoms with large electronegativity such as Au are weakly bonded to organic molecules, easily diffuse in molecular solids, and prefer to combine with each other owing to their short-range strong metallic-bonding interaction, promoting metal cluster generation in organic systems.

Self-Powered Human-Interactive Transparent Nanopaper Systems.

PubMed

Zhong, Junwen; Zhu, Hongli; Zhong, Qize; Dai, Jiaqi; Li, Wenbo; Jang, Soo-Hwan; Yao, Yonggang; Henderson, Doug; Hu, Qiyi; Hu, Liangbing; Zhou, Jun

2015-07-28

Self-powered human-interactive but invisible electronics have many applications in anti-theft and anti-fake systems for human society. In this work, for the first time, we demonstrate a transparent paper-based, self-powered, and human-interactive flexible system. The system is based on an electrostatic induction mechanism with no extra power system appended. The self-powered, transparent paper device can be used for a transparent paper-based art anti-theft system in museums or for a smart mapping anti-fake system in precious packaging and documents, by virtue of the advantages of adding/removing freely, having no impairment on the appearance of the protected objects, and being easily mass manufactured. This initial study bridges the transparent nanopaper with a self-powered and human-interactive electronic system, paving the way for the development of smart transparent paper electronics.

Estrogen-IGF-1 interactions in neuroprotection: Ischemic Stroke as a case study

PubMed Central

Sohrabji, Farida

2014-01-01

The steroid hormone 17b-estradiol and the peptide hormone insulin-like growth factor (IGF)-1 independently exert neuroprotective actions in neurologic diseases such as stroke. Only a few studies have directly addressed the interaction between the two hormone systems, however, there is a large literature that indicates potentially greater interactions between the 17b-estradiol and IGF-1 systems. The present review focuses on key issues related to this interaction including IGF-1 and sex differences and common activation of second messenger systems. Using ischemic stroke as a case study, this review also focuses on independent and cooperative actions of estrogen and IGF-1 on neuroprotection, blood brain barrier integrity, angiogenesis, inflammation and post-stroke epilepsy. Finally, the review also focuses on the astrocyte, a key mediator of post stroke repair, as a local source of 17b-estradiol and IGF-1. This review thus highlights areas where significant new research is needed to clarify the interactions between these two neuroprotectants. PMID:24882635

Analysis of airframe/engine interactions in integrated flight and propulsion control

NASA Technical Reports Server (NTRS)

Schierman, John D.; Schmidt, David K.

1991-01-01

An analysis framework for the assessment of dynamic cross-coupling between airframe and engine systems from the perspective of integrated flight/propulsion control is presented. This analysis involves to determining the significance of the interactions with respect to deterioration in stability robustness and performance, as well as critical frequency ranges where problems may occur due to these interactions. The analysis illustrated here investigates both the airframe's effects on the engine control loops and the engine's effects on the airframe control loops in two case studies. The second case study involves a multi-input/multi-output analysis of the airframe. Sensitivity studies are performed on critical interactions to examine the degradations in the system's stability robustness and performance. Magnitudes of the interactions required to cause instabilities, as well as the frequencies at which the instabilities occur are recorded. Finally, the analysis framework is expanded to include control laws which contain cross-feeds between the airframe and engine systems.

Estrogen-cholinergic interactions: Implications for cognitive aging.

PubMed

Newhouse, Paul; Dumas, Julie

2015-08-01

This article is part of a Special Issue "Estradiol and Cognition". While many studies in humans have investigated the effects of estrogen and hormone therapy on cognition, potential neurobiological correlates of these effects have been less well studied. An important site of action for estrogen in the brain is the cholinergic system. Several decades of research support the critical role of CNS cholinergic systems in cognition in humans, particularly in learning and memory formation and attention. In humans, the cholinergic system has been implicated in many aspects of cognition including the partitioning of attentional resources, working memory, inhibition of irrelevant information, and improved performance on effort-demanding tasks. Studies support the hypothesis that estradiol helps to maintain aspects of attention and verbal and visual memory. Such cognitive domains are exactly those modulated by cholinergic systems and extensive basic and preclinical work over the past several decades has clearly shown that basal forebrain cholinergic systems are dependent on estradiol support for adequate functioning. This paper will review recent human studies from our laboratories and others that have extended preclinical research examining estrogen-cholinergic interactions to humans. Studies examined include estradiol and cholinergic antagonist reversal studies in normal older women, examinations of the neural representations of estrogen-cholinergic interactions using functional brain imaging, and studies of the ability of selective estrogen receptor modulators such as tamoxifen to interact with cholinergic-mediated cognitive performance. We also discuss the implications of these studies for the underlying hypotheses of cholinergic-estrogen interactions and cognitive aging, and indications for prophylactic and therapeutic potential that may exploit these effects. Published by Elsevier Inc.

Interactions between patients, providers, and health systems and technical quality of care.

PubMed

Yelin, Edward; Yazdany, Jinoos; Tonner, Chris; Trupin, Laura; Criswell, Lindsey A; Katz, Patricia; Schmajuk, Gabriela

2015-03-01

Prior studies have established disparities by race/ethnicity and socioeconomic status (SES) in the kind, quantity, and technical quality of systemic lupus erythematosus (SLE) care and outcomes. In this study we evaluate whether disparities exist in assessments of interactions with health care providers and health plans and whether such interactions affect the technical quality of SLE care. Data derive from the Lupus Outcomes Study (LOS). Principal data collection is an annual structured phone interview including items from the Consumer Assessment of Health Plans and Interpersonal Processes of Care Scale measuring dimensions of health care interactions. We use general estimating equations to assess whether disparities exist by race/ethnicity and SES in being in the lowest quartile of ratings of such interactions and whether ratings in the lowest quartile of interactions are associated with technical quality of care after adjustment for sociodemographic and disease characteristics. In the 2012 LOS interview, there were 793 respondents, of whom 640 had ≥1 visit to their principal SLE provider. Nonwhite race/ethnicity and education were not associated with low ratings on any dimension of provider or system interaction; poverty was associated only with low ratings of health plan interactions. After adjustment for demographics, SLE status, and health care variables, ratings in the lowest quartile on all dimensions were associated with significantly lower technical quality of care. Ratings in the lowest quartile on all dimensions of interactions with providers and the health care system were associated with lower technical quality of care, potentially resulting in poorer SLE outcomes. Copyright © 2015 by the American College of Rheumatology.

Study on Collaborative Object Manipulation in Virtual Environment

NASA Astrophysics Data System (ADS)

Mayangsari, Maria Niken; Yong-Moo, Kwon

This paper presents comparative study on network collaboration performance in different immersion. Especially, the relationship between user collaboration performance and degree of immersion provided by the system is addressed and compared based on several experiments. The user tests on our system include several cases: 1) Comparison between non-haptics and haptics collaborative interaction over LAN, 2) Comparison between non-haptics and haptics collaborative interaction over Internet, and 3) Analysis of collaborative interaction between non-immersive and immersive display environments.

A conceptual network model of the air transportation system. the basic level 1 model.

DOT National Transportation Integrated Search

1971-04-01

A basic conceptual model of the entire Air Transportation System is being developed to serve as an analytical tool for studying the interactions among the system elements. The model is being designed to function in an interactive computer graphics en...

Interactions between surface discharges induced by volume discharges in a dielectric barrier discharge system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Yenan; Dong, Lifang, E-mail: donglfhbu@163.com; Zhao, Longhu

2014-10-15

The interaction between micro-discharges involved in surface discharges (SDs) is studied in dielectric barrier discharge system. Instantaneous images taken by high speed cameras show that the SDs are induced by volume discharges (VDs). They cannot cross the midperpendicular of two neighbouring volume charges at low voltage while they stretch along it at high voltage, indicating that there is interaction between SDs. The differences of plasma parameters between SD and VD are studied by optical emission spectroscopy. The simulation of the electric fields of the wall charges accumulated by VD further confirms the existence of the interaction.

Spatial resolution study and power calibration of the high-k scattering system on NSTX.

PubMed

Lee, W; Park, H K; Cho, M H; Namkung, W; Smith, D R; Domier, C W; Luhmann, N C

2008-10-01

NSTX high-k scattering system has been extensively utilized in studying the microturbulence and coherent waves. An absolute calibration of the scattering system was performed employing a new millimeter-wave source and calibrated attenuators. One of the key parameters essential for the calibration of the multichannel scattering system is the interaction length. This interaction length is significantly different from the conventional one due to the curvature and magnetic shear effect.

Effects of noise and confidence thresholds in nominal and metric Axelrod dynamics of social influence

NASA Astrophysics Data System (ADS)

de Sanctis, Luca; Galla, Tobias

2009-04-01

We study the effects of bounded confidence thresholds and of interaction and external noise on Axelrod’s model of social influence. Our study is based on a combination of numerical simulations and an integration of the mean-field master equation describing the system in the thermodynamic limit. We find that interaction thresholds affect the system only quantitatively, but that they do not alter the basic phase structure. The known crossover between an ordered and a disordered state in finite systems subject to external noise persists in models with general confidence threshold. Interaction noise here facilitates the dynamics and reduces relaxation times. We also study Axelrod systems with metric features and point out similarities and differences compared to models with nominal features.

Using the Diffusion of Innovation Theory to Explain the Degree of English Teachers' Adoption of Interactive Whiteboards in the Modern Systems School in Jordan: A Case Study

ERIC Educational Resources Information Center

Jwaifell, Mustafa; Gasaymeh, Al-Mothana

2013-01-01

This study aimed to explain the use of interactive whiteboards (IWBs) by English female teachers in Modern Systems School in Jordan. Viewed from the lens of Rogers' Diffusion of Innovation Theory, the study examined and reported teachers' use of IWB and its features that have impact on their decisions to adopt it in Modern Systems School . The…

Comparative study on collaborative interaction in non-immersive and immersive systems

NASA Astrophysics Data System (ADS)

Shahab, Qonita M.; Kwon, Yong-Moo; Ko, Heedong; Mayangsari, Maria N.; Yamasaki, Shoko; Nishino, Hiroaki

2007-09-01

This research studies the Virtual Reality simulation for collaborative interaction so that different people from different places can interact with one object concurrently. Our focus is the real-time handling of inputs from multiple users, where object's behavior is determined by the combination of the multiple inputs. Issues addressed in this research are: 1) The effects of using haptics on a collaborative interaction, 2) The possibilities of collaboration between users from different environments. We conducted user tests on our system in several cases: 1) Comparison between non-haptics and haptics collaborative interaction over LAN, 2) Comparison between non-haptics and haptics collaborative interaction over Internet, and 3) Analysis of collaborative interaction between non-immersive and immersive display environments. The case studies are the interaction of users in two cases: collaborative authoring of a 3D model by two users, and collaborative haptic interaction by multiple users. In Virtual Dollhouse, users can observe physics law while constructing a dollhouse using existing building blocks, under gravity effects. In Virtual Stretcher, multiple users can collaborate on moving a stretcher together while feeling each other's haptic motions.

Study of ultrasonic attenuation in f-electron systems in the paramagnetic limit of Coulomb interaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shadangi, Asit Ku., E-mail: asitshad@iopb.res.in; Rout, G. C., E-mail: gcr@iopb.res.in

2015-05-15

We report here a microscopic model study of ultrasonic attenuation in f-electron systems based on Periodic Anderson Model in which Coulomb interaction is considered within a mean-field approximation for a weak interaction. The Phonon is coupled to the conduction band and f-electrons. The phonon Green's function is calculated by Zubarev's technique of the Green's function method. The temperature dependent ultrasonic attenuation co-efficient is calculated from the imaginary part of the phonon self-energy in the dynamic and long wave length limit. The f-electron occupation number is calculated self-consistently in paramagnetic limit of Coulomb interaction. The effect of the Coulomb interaction onmore » ultrasonic attenuation is studied by varying the phonon coupling parameters to the conduction and f-electrons, hybridization strength, the position of f-level and the Coulomb interaction Strength. Results are discussed on the basis of experimental results.« less

A Study of the Construct Validity of the Interactive Computer Interview System (ICIS) Using Student Evaluations as the Outcome Measure

ERIC Educational Resources Information Center

Gardner, Robby Christopher

2009-01-01

The primary objective of this study was to compare the individual teacher interview scores from the Interactive Computer Interview System (ICIS) with their students' responses to "The Steps to Excellence Student Questionnaire". Specifically, the study examined the correlation among the teacher interviews across four themes of the ICIS ("Knowledge…

Network Analysis of Drug-target Interactions: A Study on FDA-approved New Molecular Entities Between 2000 to 2015.

PubMed

Lin, Hui-Heng; Zhang, Le-Le; Yan, Ru; Lu, Jin-Jian; Hu, Yuanjia

2017-09-25

The U.S. Food and Drug Administration (FDA) approves new drugs every year. Drug targets are some of the most important interactive molecules for drugs, as they have a significant impact on the therapeutic effects of drugs. In this work, we thoroughly analyzed the data of small molecule drugs approved by the U.S. FDA between 2000 and 2015. Specifically, we focused on seven classes of new molecular entity (NME) classified by the anatomic therapeutic chemical (ATC) classification system. They were NMEs and their corresponding targets for the cardiovascular system, respiratory system, nerve system, general anti-infective systemic, genito-urinary system and sex hormones, alimentary tract and metabolisms, and antineoplastic and immunomodulating agents. To study the drug-target interaction on the systems level, we employed network topological analysis and multipartite network projections. As a result, the drug-target relations of different kinds of drugs were comprehensively characterized and global pictures of drug-target, drug-drug, and target-target interactions were visualized and analyzed from the perspective of network models.

Observational Coding Systems of Parent-Child Interactions During Painful Procedures: A Systematic Review.

PubMed

Bai, Jinbing; Swanson, Kristen M; Santacroce, Sheila J

2018-01-01

Parent interactions with their child can influence the child's pain and distress during painful procedures. Reliable and valid interaction analysis systems (IASs) are valuable tools for capturing these interactions. The extent to which IASs are used in observational research of parent-child interactions is unknown in pediatric populations. To identify and evaluate studies that focus on assessing psychometric properties of initial iterations/publications of observational coding systems of parent-child interactions during painful procedures. To identify and evaluate studies that focus on assessing psychometric properties of initial iterations/publications of observational coding systems of parent-child interactions during painful procedures. Computerized databases searched included PubMed, CINAHL, PsycINFO, Health and Psychosocial Instruments, and Scopus. Timeframes covered from inception of the database to January 2017. Studies were included if they reported use or psychometrics of parent-child IASs. First assessment was whether the parent-child IASs were theory-based; next, using the Society of Pediatric Psychology Assessment Task Force criteria IASs were assigned to one of three categories: well-established, approaching well-established, or promising. A total of 795 studies were identified through computerized searches. Eighteen studies were ultimately determined to be eligible for inclusion in the review and 17 parent-child IASs were identified from these 18 studies. Among the 17 coding systems, 14 were suitable for use in children age 3 years or more; two were theory-based; and 11 included verbal and nonverbal parent behaviors that promoted either child coping or child distress. Four IASs were assessed as well-established; seven approached well-established; and six were promising. Findings indicate a need for the development of theory-based parent-child IASs that consider both verbal and nonverbal parent behaviors during painful procedures. Findings also suggest a need for further testing of those parent-child IASs deemed "approaching well-established" or "promising". © 2017 World Institute of Pain.

Review of health information technology usability study methodologies

PubMed Central

Bakken, Suzanne

2011-01-01

Usability factors are a major obstacle to health information technology (IT) adoption. The purpose of this paper is to review and categorize health IT usability study methods and to provide practical guidance on health IT usability evaluation. 2025 references were initially retrieved from the Medline database from 2003 to 2009 that evaluated health IT used by clinicians. Titles and abstracts were first reviewed for inclusion. Full-text articles were then examined to identify final eligibility studies. 629 studies were categorized into the five stages of an integrated usability specification and evaluation framework that was based on a usability model and the system development life cycle (SDLC)-associated stages of evaluation. Theoretical and methodological aspects of 319 studies were extracted in greater detail and studies that focused on system validation (SDLC stage 2) were not assessed further. The number of studies by stage was: stage 1, task-based or user–task interaction, n=42; stage 2, system–task interaction, n=310; stage 3, user–task–system interaction, n=69; stage 4, user–task–system–environment interaction, n=54; and stage 5, user–task–system–environment interaction in routine use, n=199. The studies applied a variety of quantitative and qualitative approaches. Methodological issues included lack of theoretical framework/model, lack of details regarding qualitative study approaches, single evaluation focus, environmental factors not evaluated in the early stages, and guideline adherence as the primary outcome for decision support system evaluations. Based on the findings, a three-level stratified view of health IT usability evaluation is proposed and methodological guidance is offered based upon the type of interaction that is of primary interest in the evaluation. PMID:21828224

Computer Self-Efficacy and Factors Influencing E-Learning Effectiveness

ERIC Educational Resources Information Center

Chien, Tien-Chen

2012-01-01

Purpose: The purpose of this study is to investigate the influences of system and instructor factors on e-learning effectiveness under the interactions of computer self-efficacy. In this study, the factors of the e-learning system are functionality, interaction, and response. The factors of the e-learning instructor are attitude, technical skills,…

Strategic Design of an Interactive Video Learning Lab (IVL).

ERIC Educational Resources Information Center

Switzer, Ralph V., Jr.; Switzer, Jamie S.

1993-01-01

Describes a study that researched elements necessary for the design of an interactive video learning (IVL) lab for business courses. Highlights include a review of pertinent literature; guidelines for the use of an IVL lab; IVL systems integration; system specifications; hardware costs; and system software. (five references) (LRW)

Boolean decision problems with competing interactions on scale-free networks: Equilibrium and nonequilibrium behavior in an external bias

NASA Astrophysics Data System (ADS)

Zhu, Zheng; Andresen, Juan Carlos; Moore, M. A.; Katzgraber, Helmut G.

2014-02-01

We study the equilibrium and nonequilibrium properties of Boolean decision problems with competing interactions on scale-free networks in an external bias (magnetic field). Previous studies at zero field have shown a remarkable equilibrium stability of Boolean variables (Ising spins) with competing interactions (spin glasses) on scale-free networks. When the exponent that describes the power-law decay of the connectivity of the network is strictly larger than 3, the system undergoes a spin-glass transition. However, when the exponent is equal to or less than 3, the glass phase is stable for all temperatures. First, we perform finite-temperature Monte Carlo simulations in a field to test the robustness of the spin-glass phase and show that the system has a spin-glass phase in a field, i.e., exhibits a de Almeida-Thouless line. Furthermore, we study avalanche distributions when the system is driven by a field at zero temperature to test if the system displays self-organized criticality. Numerical results suggest that avalanches (damage) can spread across the whole system with nonzero probability when the decay exponent of the interaction degree is less than or equal to 2, i.e., that Boolean decision problems on scale-free networks with competing interactions can be fragile when not in thermal equilibrium.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Jianguo; Hull, Vanessa; Batistella, Mateus

Interactions between distant places are increasingly widespread and influential, often leading to unexpected outcomes with profound implications for sustainability. Numerous sustainability studies have been conducted within a particular place with little attention to the impacts of distant interactions on sustainability in multiple places. Although distant forces have been studied, they are usually treated as exogenous variables and feedbacks have been rarely considered. To understand and integrate various distant interactions better, we propose an integrated framework based on telecoupling – an umbrella concept that refers to socioeconomic and environmental interactions over distances. The concept of telecoupling is a logical extension ofmore » research on coupled human and natural systems, in which human and natural systems interact within particular places. The telecoupling framework contains five major interrelated components (coupled human and natural systems, agents, flows, causes, and effects). We illustrate the framework using two examples of distant interactions, highlight the implications of the framework, and discuss research needs and approaches to move research on telecouplings forward. The framework can help better analyze system components and their interrelationships, identify research gaps, detect hidden costs and untapped benefits, provide a useful means to incorporate feedbacks as well as trade-offs and synergies across multiple places (sending, receiving, and spillover systems), and improve the understanding of distant interactions and the effectiveness of policies for socioeconomic and environmental sustainability from local to global levels.« less

A study of interactive control scheduling and economic assessment for robotic systems

NASA Technical Reports Server (NTRS)

1982-01-01

A class of interactive control systems is derived by generalizing interactive manipulator control systems. Tasks of interactive control systems can be represented as a network of a finite set of actions which have specific operational characteristics and specific resource requirements, and which are of limited duration. This has enabled the decomposition of the overall control algorithm simultaneously and asynchronously. The performance benefits of sensor referenced and computer-aided control of manipulators in a complex environment is evaluated. The first phase of the CURV arm control system software development and the basic features of the control algorithms and their software implementation are presented. An optimal solution for a production scheduling problem that will be easy to implement in practical situations is investigated.

Designing Interactive Learning Systems.

ERIC Educational Resources Information Center

Barker, Philip

1990-01-01

Describes multimedia, computer-based interactive learning systems that support various forms of individualized study. Highlights include design models; user interfaces; design guidelines; media utilization paradigms, including hypermedia and learner-controlled models; metaphors and myths; authoring tools; optical media; workstations; four case…

Systems engineering interfaces: A model based approach

NASA Astrophysics Data System (ADS)

Fosse, E.; Delp, C. L.

The engineering of interfaces is a critical function of the discipline of Systems Engineering. Included in interface engineering are instances of interaction. Interfaces provide the specifications of the relevant properties of a system or component that can be connected to other systems or components while instances of interaction are identified in order to specify the actual integration to other systems or components. Current Systems Engineering practices rely on a variety of documents and diagrams to describe interface specifications and instances of interaction. The SysML[1] specification provides a precise model based representation for interfaces and interface instance integration. This paper will describe interface engineering as implemented by the Operations Revitalization Task using SysML, starting with a generic case and culminating with a focus on a Flight System to Ground Interaction. The reusability of the interface engineering approach presented as well as its extensibility to more complex interfaces and interactions will be shown. Model-derived tables will support the case studies shown and are examples of model-based documentation products.

Tool for simplifying the complex interactions within resilient communities

NASA Astrophysics Data System (ADS)

Stwertka, C.; Albert, M. R.; White, K. D.

2016-12-01

In recent decades, scientists have observed and documented impacts from climate change that will impact multiple sectors, will be impacted by decisions from multiple sectors, and will change over time. This complex human-engineered system has a large number of moving, interacting parts, which are interdependent and evolve over time towards their purpose. Many of the existing resilience frameworks and vulnerability frameworks focus on interactions between the domains, but do not include the structure of the interactions. We present an engineering systems approach to investigate the structural elements that influence a community's ability to be resilient. In this presentation we will present and analyze four common methods for building community resilience, utilizing our common framework. For several existing case studies we examine the stress points in the system and identify the impacts on the outcomes from the case studies. In ongoing research we will apply our system tool to a new case in the field.

Mother, Father, and Infant as an Interactive System.

ERIC Educational Resources Information Center

Pedersen, Frank A.

This study investigates three types of reciprocal interactions among members of the family unit (father, mother and infant): father-infant interaction affecting child's development, father-infant interaction affecting mother's behavior, and husband-wife interaction affecting mother's behavior. Data from a sample of 39 healthy first-born infants…

Acoustically mediated long-range interaction among multiple spherical particles exposed to a plane standing wave

NASA Astrophysics Data System (ADS)

Zhang, Shenwei; Qiu, Chunyin; Wang, Mudi; Ke, Manzhu; Liu, Zhengyou

2016-11-01

In this work, we study the acoustically mediated interaction forces among multiple well-separated spherical particles trapped in the same node or antinode plane of a standing wave. An analytical expression of the acoustic interaction force is derived, which is accurate even for the particles beyond the Rayleigh limit. Interestingly, the multi-particle system can be decomposed into a series of independent two-particle systems described by pairwise interactions. Each pairwise interaction is a long-range interaction, as characterized by a soft oscillatory attenuation (at the power exponent of n = -1 or -2). The vector additivity of the acoustic interaction force, which is not well expected considering the nonlinear nature of the acoustic radiation force, is greatly useful for exploring a system consisting of a large number of particles. The capability of self-organizing a big particle cluster can be anticipated through such acoustically controllable long-range interaction.

Automated Analysis of Fluorescence Microscopy Images to Identify Protein-Protein Interactions

DOE PAGES

Venkatraman, S.; Doktycz, M. J.; Qi, H.; ...

2006-01-01

The identification of protein interactions is important for elucidating biological networks. One obstacle in comprehensive interaction studies is the analyses of large datasets, particularly those containing images. Development of an automated system to analyze an image-based protein interaction dataset is needed. Such an analysis system is described here, to automatically extract features from fluorescence microscopy images obtained from a bacterial protein interaction assay. These features are used to relay quantitative values that aid in the automated scoring of positive interactions. Experimental observations indicate that identifying at least 50% positive cells in an image is sufficient to detect a protein interaction.more » Based on this criterion, the automated system presents 100% accuracy in detecting positive interactions for a dataset of 16 images. Algorithms were implemented using MATLAB and the software developed is available on request from the authors.« less

Study on fluid-structure interaction in liquid oxygen feeding pipe systems using finite volume method

NASA Astrophysics Data System (ADS)

Wei, Xin; Sun, Bing

2011-10-01

The fluid-structure interaction may occur in space launch vehicles, which would lead to bad performance of vehicles, damage equipments on vehicles, or even affect astronauts' health. In this paper, analysis on dynamic behavior of liquid oxygen (LOX) feeding pipe system in a large scale launch vehicle is performed, with the effect of fluid-structure interaction (FSI) taken into consideration. The pipe system is simplified as a planar FSI model with Poisson coupling and junction coupling. Numerical tests on pipes between the tank and the pump are solved by the finite volume method. Results show that restrictions weaken the interaction between axial and lateral vibrations. The reasonable results regarding frequencies and modes indicate that the FSI affects substantially the dynamic analysis, and thus highlight the usefulness of the proposed model. This study would provide a reference to the pipe test, as well as facilitate further studies on oscillation suppression.

Students' Peer Interactions within a Cohort and in Host Countries during a Short-Term Study Abroad

ERIC Educational Resources Information Center

Jessup-Anger, Jody E.; Aragones, Aileen

2013-01-01

In this qualitative case study, we explored students' peer interactions within their cohort and in the host countries during a short-term study abroad. Framed by Bronfenbrenner's (1993) ecological systems theory, findings revealed that students spent considerable energy reflecting on interactions with peers. The students considered themselves…

The evolution of early cellular systems viewed through the lens of biological interactions.

PubMed

Poole, Anthony M; Lundin, Daniel; Rytkönen, Kalle T

2015-01-01

The minimal cell concept represents a pragmatic approach to the question of how few genes are required to run a cell. This is a helpful way to build a parts-list, and has been more successful than attempts to deduce a minimal gene set for life by inferring the gene repertoire of the last universal common ancestor, as few genes trace back to this hypothetical ancestral state. However, the study of minimal cellular systems is the study of biological outliers where, by practical necessity, coevolutionary interactions are minimized or ignored. In this paper, we consider the biological context from which minimal genomes have been removed. For instance, some of the most reduced genomes are from endosymbionts and are the result of coevolutionary interactions with a host; few such organisms are "free-living." As few, if any, biological systems exist in complete isolation, we expect that, as with modern life, early biological systems were part of an ecosystem, replete with organismal interactions. We favor refocusing discussions of the evolution of cellular systems on processes rather than gene counts. We therefore draw a distinction between a pragmatic minimal cell (an interesting engineering problem), a distributed genome (a system resulting from an evolutionary transition involving more than one cell) and the looser coevolutionary interactions that are ubiquitous in ecosystems. Finally, we consider the distributed genome and coevolutionary interactions between genomic entities in the context of early evolution.

Modeling and control of non-square MIMO system using relay feedback.

PubMed

Kalpana, D; Thyagarajan, T; Gokulraj, N

2015-11-01

This paper proposes a systematic approach for the modeling and control of non-square MIMO systems in time domain using relay feedback. Conventionally, modeling, selection of the control configuration and controller design of non-square MIMO systems are performed using input/output information of direct loop, while the output of undesired responses that bears valuable information on interaction among the loops are not considered. However, in this paper, the undesired response obtained from relay feedback test is also taken into consideration to extract the information about the interaction between the loops. The studies are performed on an Air Path Scheme of Turbocharged Diesel Engine (APSTDE) model, which is a typical non-square MIMO system, with input and output variables being 3 and 2 respectively. From the relay test response, the generalized analytical expressions are derived and these analytical expressions are used to estimate unknown system parameters and also to evaluate interaction measures. The interaction is analyzed by using Block Relative Gain (BRG) method. The model thus identified is later used to design appropriate controller to carry out closed loop studies. Closed loop simulation studies were performed for both servo and regulatory operations. Integral of Squared Error (ISE) performance criterion is employed to quantitatively evaluate performance of the proposed scheme. The usefulness of the proposed method is demonstrated on a lab-scale Two-Tank Cylindrical Interacting System (TTCIS), which is configured as a non-square system. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Identifying high risk medications causing potential drug-drug interactions in outpatients: A prescription database study based on an online surveillance system.

PubMed

Toivo, T M; Mikkola, J A V; Laine, K; Airaksinen, M

2016-01-01

Drug-drug interactions (DDIs) are a significant cause for adverse drug events (ADEs). DDIs are often predictable and preventable, but their prevention and management require systematic service development. Most DDI studies focus on interaction rates in hospitalized patients. Less is known of DDIs in outpatients, particularly how community pharmacists could contribute to DDI management by applying their surveillance systems for identifying high-risk medications. The study was related to the implementation of the first online DDI surveillance system in Finnish community pharmacies. The goal was to demonstrate how community pharmacies can utilize their prospective surveillance system 1) for identifying high risk medications causing potential DDIs in outpatients, 2) for collaborative service development with local physicians, and 3) for academic risk management research purposes. All DDI alerts given by the online surveillance system were collected during a one-month period in 16 out of 17 University Pharmacy outlets in Finland, covering approximately 10% of the national outpatient prescription volume. The surveillance system was based on the FASS database, which categorizes DDIs into four classes (A-D) according to their clinical significance. Potential drug-drug DDIs were analyzed for 276,891 dispensed community pharmacy prescriptions. Potential DDIs were associated with 10.8%, or 31,110 of these prescriptions. Clinically significant interaction alerts categorized as FASS classes D (most severe, should be avoided) and C (clinically significant but controllable) were associated with 0.5% and 7.0% of the prescriptions, respectively. Methotrexate and warfarin had the highest risk of causing potentially serious (class D) interactions. These interaction alerts were most frequently between methotrexate and NSAIDs and warfarin and NSAIDs. In general, NSAIDs were the most commonly interacting drugs in this study. This study demonstrates that community pharmacies can actively contribute to DDI risk management and systematically use their surveillance systems for identifying patients having clinically significant DDIs. The findings also indicate that the majority of potentially serious interactions in outpatients involve a limited number of drugs, particularly NSAIDs, warfarin and methotrexate. Further research should focus on community pharmacists' involvement in DDI risk management in collaboration with local health care providers. Copyright © 2015 Elsevier Inc. All rights reserved.

Segmentation and additive approach: A reliable technique to study noncovalent interactions of large molecules at the surface of single-wall carbon nanotubes.

PubMed

Torres, Ana M; Scheiner, Steve; Roy, Ajit K; Garay-Tapia, Andrés M; Bustamante, John; Kar, Tapas

2016-08-05

This investigation explores a new protocol, named Segmentation and Additive approach (SAA), to study exohedral noncovalent functionalization of single-walled carbon nanotubes with large molecules, such as polymers and biomolecules, by segmenting the entire system into smaller units to reduce computational cost. A key criterion of the segmentation process is the preservation of the molecular structure responsible for stabilization of the entire system in smaller segments. Noncovalent interaction of linoleic acid (LA, C18 H32 O2 ), a fatty acid, at the surface of a (10,0) zigzag nanotube is considered for test purposes. Three smaller segmented models have been created from the full (10,0)-LA system and interaction energies were calculated for these models and compared with the full system at different levels of theory, namely ωB97XD, LDA. The success of this SAA is confirmed as the sum of the interaction energies is in very good agreement with the total interaction energy. Besides reducing computational cost, another merit of SAA is an estimation of the contributions from different sections of the large system to the total interaction energy which can be studied in-depth using a higher level of theory to estimate several properties of each segment. On the negative side, bulk properties, such as HOMO-LUMO (highest occupied molecular orbital - lowest occupied molecular orbital) gap, of the entire system cannot be estimated by adding results from segment models. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Information of Complex Systems and Applications in Agent Based Modeling.

PubMed

Bao, Lei; Fritchman, Joseph C

2018-04-18

Information about a system's internal interactions is important to modeling the system's dynamics. This study examines the finer categories of the information definition and explores the features of a type of local information that describes the internal interactions of a system. Based on the results, a dual-space agent and information modeling framework (AIM) is developed by explicitly distinguishing an information space from the material space. The two spaces can evolve both independently and interactively. The dual-space framework can provide new analytic methods for agent based models (ABMs). Three examples are presented including money distribution, individual's economic evolution, and artificial stock market. The results are analyzed in the dual-space, which more clearly shows the interactions and evolutions within and between the information and material spaces. The outcomes demonstrate the wide-ranging applicability of using the dual-space AIMs to model and analyze a broad range of interactive and intelligent systems.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beck, Ashley; Hunt, Kristopher; Bernstein, Hans C.

Interest in microbial communities for bioprocessing has surged in recent years based on the potential to optimize multiple tasks simultaneously and to enhance process productivity and stability. The presence and magnitude of these desirable system properties often result from interactions between functionally distinct community members. The importance of interactions, while appreciated by some disciplines for decades, has gained interest recently due to the development of ‘omics techniques, polymicrobial culturing approaches, and computational methods which has made the systems-level analysis of interacting components more tractable. This review defines and categorizes natural and engineered system components, interactions, and emergent properties, as wellmore » as presents three ecological theories relevant to microbial communities. Case studies are interpreted to illustrate components, interactions, emergent properties and agreement with theoretical concepts. A general foundation is laid to facilitate interpretation of current systems and to aid in future design of microbial systems for the next generation of bioprocesses.« less

The Effects of Real-Time Interactive Multimedia Teleradiology System

PubMed Central

Al-Safadi, Lilac

2016-01-01

This study describes the design of a real-time interactive multimedia teleradiology system and assesses how the system is used by referring physicians in point-of-care situations and supports or hinders aspects of physician-radiologist interaction. We developed a real-time multimedia teleradiology management system that automates the transfer of images and radiologists' reports and surveyed physicians to triangulate the findings and to verify the realism and results of the experiment. The web-based survey was delivered to 150 physicians from a range of specialties. The survey was completed by 72% of physicians. Data showed a correlation between rich interactivity, satisfaction, and effectiveness. The results of our experiments suggest that real-time multimedia teleradiology systems are valued by referring physicians and may have the potential for enhancing their practice and improving patient care and highlight the critical role of multimedia technologies to provide real-time multimode interactivity in current medical care. PMID:27294118

Autonomous multispecies reaction-diffusion systems with more-than-two-site interactions

NASA Astrophysics Data System (ADS)

Shariati, Ahmad; Aghamohammadi, Amir; Khorrami, Mohammad

2001-12-01

Autonomous multispecies systems with more-than-two-neighbor interactions are studied. Conditions necessary and sufficient for the closedness of the evolution equations of the n-point functions are obtained. The average numbers of the particles at each site for one species and three-site interactions, and its generalization to the more-than-three-site interactions, are explicitly obtained. Generalizations of the Glauber model in different directions, using generalized rates, generalized numbers of states at each site, and generalized numbers of interacting sites, are also investigated.

Analysis of candidates for interacting galaxy clusters. I. A1204 and A2029/A2033

NASA Astrophysics Data System (ADS)

Gonzalez, Elizabeth Johana; de los Rios, Martín; Oio, Gabriel A.; Lang, Daniel Hernández; Tagliaferro, Tania Aguirre; Domínguez R., Mariano J.; Castellón, José Luis Nilo; Cuevas L., Héctor; Valotto, Carlos A.

2018-04-01

Context. Merging galaxy clusters allow for the study of different mass components, dark and baryonic, separately. Also, their occurrence enables to test the ΛCDM scenario, which can be used to put constraints on the self-interacting cross-section of the dark-matter particle. Aim. It is necessary to perform a homogeneous analysis of these systems. Hence, based on a recently presented sample of candidates for interacting galaxy clusters, we present the analysis of two of these cataloged systems. Methods: In this work, the first of a series devoted to characterizing galaxy clusters in merger processes, we perform a weak lensing analysis of clusters A1204 and A2029/A2033 to derive the total masses of each identified interacting structure together with a dynamical study based on a two-body model. We also describe the gas and the mass distributions in the field through a lensing and an X-ray analysis. This is the first of a series of works which will analyze these type of system in order to characterize them. Results: Neither merging cluster candidate shows evidence of having had a recent merger event. Nevertheless, there is dynamical evidence that these systems could be interacting or could interact in the future. Conclusions: It is necessary to include more constraints in order to improve the methodology of classifying merging galaxy clusters. Characterization of these clusters is important in order to properly understand the nature of these systems and their connection with dynamical studies.

Reducing drug–herb interaction risk with a computerized reminder system

PubMed Central

Lin, Sheng-Shing; Tsai, Chiu-Lin; Tu, Ching-Yeh; Hsieh, Ching-Liang

2015-01-01

Background Traditional Chinese medicine (TCM) and Western medicine are both popular in Taiwan. Approximately 14.1% of Taiwanese residents use Western drugs and Chinese herbs concurrently; therefore, drug–herb interaction is critical to patient safety. This paper presents a new procedure for reducing the risk of drug interactions. Methods Hospital computer systems are modified to ensure that drug–herb interactions are automatically detected when a TCM practitioner is writing a prescription. A pop-up reminder appears, warning of interactions, and the practitioner may adjust doses, delete herbs, or leave the prescription unchanged. A pharmacist will receive interaction information through the system and provide health education to the patient. Results During the 2011–2013 study period, 256 patients received 891 herbal prescriptions with potential drug–herb interactions. Three of the 50 patients who concurrently used ginseng and antidiabetic drugs manifested hypoglycemia (fasting blood sugar level ≤70 mg/dL). Conclusion Drug–herb interactions can cause adverse reactions. A computerized reminder system can enable TCM practitioners to reduce the risk of drug–herb interactions. In addition, health education for patients is crucial in avoiding adverse reaction by the interactions. PMID:25733840

Punctuated equilibrium dynamics in human communications

NASA Astrophysics Data System (ADS)

Peng, Dan; Han, Xiao-Pu; Wei, Zong-Wen; Wang, Bing-Hong

2015-10-01

A minimal model based on network incorporating individual interactions is proposed to study the non-Poisson statistical properties of human behavior: individuals in system interact with their neighbors, the probability of an individual acting correlates to its activity, and all the individuals involved in action will change their activities randomly. The model reproduces varieties of spatial-temporal patterns observed in empirical studies of human daily communications, providing insight into various human activities and embracing a range of realistic social interacting systems, particularly, intriguing bimodal phenomenon. This model bridges priority queueing theory and punctuated equilibrium dynamics, and our modeling and analysis is likely to shed light on non-Poisson phenomena in many complex systems.

Weather Observers: A Manipulative Augmented Reality System for Weather Simulations at Home, in the Classroom, and at a Museum

ERIC Educational Resources Information Center

Hsiao, Hsien-Sheng; Chang, Cheng-Sian; Lin, Chien-Yu; Wang, Yau-Zng

2016-01-01

This study focused on how to enhance the interactivity and usefulness of augmented reality (AR) by integrating manipulative interactive tools with a real-world environment. A manipulative AR (MAR) system, which included 3D interactive models and manipulative aids, was designed and developed to teach the unit "Understanding Weather" in a…

Do early sensory cortices integrate cross-modal information?

PubMed

Kayser, Christoph; Logothetis, Nikos K

2007-09-01

Our different senses provide complementary evidence about the environment and their interaction often aids behavioral performance or alters the quality of the sensory percept. A traditional view defers the merging of sensory information to higher association cortices, and posits that a large part of the brain can be reduced into a collection of unisensory systems that can be studied in isolation. Recent studies, however, challenge this view and suggest that cross-modal interactions can already occur in areas hitherto regarded as unisensory. We review results from functional imaging and electrophysiology exemplifying cross-modal interactions that occur early during the evoked response, and at the earliest stages of sensory cortical processing. Although anatomical studies revealed several potential origins of these cross-modal influences, there is yet no clear relation between particular functional observations and specific anatomical connections. In addition, our view on sensory integration at the neuronal level is coined by many studies on subcortical model systems of sensory integration; yet, the patterns of cross-modal interaction in cortex deviate from these model systems in several ways. Consequently, future studies on cortical sensory integration need to leave the descriptive level and need to incorporate cross-modal influences into models of the organization of sensory processing. Only then will we be able to determine whether early cross-modal interactions truly merit the label sensory integration, and how they increase a sensory system's ability to scrutinize its environment and finally aid behavior.

Emergent Fermi Sea in A System of Interacting Bosons

NASA Astrophysics Data System (ADS)

Wu, Yinghai; Jain, Jainendra

2015-03-01

An understanding of the possible ways in which interactions can produce fundamentally new emergent many-body states is a central problem of condensed matter physics. We ask if a Fermi sea can arise in a system of bosons subject to contact interaction. Based on exact diagonalization studies and variational wave functions, we predict that such a state is likely to occur when a system of two-component bosons in two dimensions, interacting via a species independent contact interaction, is exposed to a synthetic magnetic field of strength that corresponds to a filling factor of unity. The bosons each bind a single vortex as a result of the repulsive interaction, and these fermionic bound states, namely composite fermions, form a spin-singlet Fermi sea. Financial support from the DOE under Grant No. DE-SC0005042.

Study of Personalized Network Tutoring System Based on Emotional-cognitive Interaction

NASA Astrophysics Data System (ADS)

Qi, Manfei; Ma, Ding; Wang, Wansen

Aiming at emotion deficiency in present Network tutoring system, a lot of negative effects is analyzed and corresponding countermeasures are proposed. The model of Personalized Network tutoring system based on Emotional-cognitive interaction is constructed in the paper. The key techniques of realizing the system such as constructing emotional model and adjusting teaching strategies are also introduced.

Space Shuttle interactive meteorological data system study

NASA Technical Reports Server (NTRS)

Young, J. T.; Fox, R. J.; Benson, J. M.; Rueden, J. P.; Oehlkers, R. A.

1985-01-01

Although focused toward the operational meteorological support review and definition of an operational meteorological interactive data display systems (MIDDS) requirements for the Space Meteorology Support Group at NASA/Johnson Space Center, the total operational meteorological support requirements and a systems concept for the MIDDS network integration of NASA and Air Force elements to support the National Space Transportation System are also addressed.

Proteomics and plant disease: advances in combating a major threat to the global food supply.

PubMed

Rampitsch, Christof; Bykova, Natalia V

2012-02-01

The study of plant disease and immunity is benefiting tremendously from proteomics. Parallel streams of research from model systems, from pathogens in vitro and from the relevant pathogen-crop interactions themselves have begun to reveal a model of how plants succumb to invading pathogens and how they defend themselves without the benefit of a circulating immune system. In this review, we discuss the contribution of proteomics to these advances, drawing mainly on examples from crop-fungus interactions, from Arabidopsis-bacteria interactions, from elicitor-based model systems and from pathogen studies, to highlight also the important contribution of non-crop systems to advancing crop protection. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transcriptomic Studies of Malaria: a Paradigm for Investigation of Systemic Host-Pathogen Interactions

PubMed Central

2018-01-01

SUMMARY Transcriptomics, the analysis of genome-wide RNA expression, is a common approach to investigate host and pathogen processes in infectious diseases. Technical and bioinformatic advances have permitted increasingly thorough analyses of the association of RNA expression with fundamental biology, immunity, pathogenesis, diagnosis, and prognosis. Transcriptomic approaches can now be used to realize a previously unattainable goal, the simultaneous study of RNA expression in host and pathogen, in order to better understand their interactions. This exciting prospect is not without challenges, especially as focus moves from interactions in vitro under tightly controlled conditions to tissue- and systems-level interactions in animal models and natural and experimental infections in humans. Here we review the contribution of transcriptomic studies to the understanding of malaria, a parasitic disease which has exerted a major influence on human evolution and continues to cause a huge global burden of disease. We consider malaria a paradigm for the transcriptomic assessment of systemic host-pathogen interactions in humans, because much of the direct host-pathogen interaction occurs within the blood, a readily sampled compartment of the body. We illustrate lessons learned from transcriptomic studies of malaria and how these lessons may guide studies of host-pathogen interactions in other infectious diseases. We propose that the potential of transcriptomic studies to improve the understanding of malaria as a disease remains partly untapped because of limitations in study design rather than as a consequence of technological constraints. Further advances will require the integration of transcriptomic data with analytical approaches from other scientific disciplines, including epidemiology and mathematical modeling. PMID:29695497

Transcriptomic Studies of Malaria: a Paradigm for Investigation of Systemic Host-Pathogen Interactions.

PubMed

Lee, Hyun Jae; Georgiadou, Athina; Otto, Thomas D; Levin, Michael; Coin, Lachlan J; Conway, David J; Cunnington, Aubrey J

2018-06-01

Transcriptomics, the analysis of genome-wide RNA expression, is a common approach to investigate host and pathogen processes in infectious diseases. Technical and bioinformatic advances have permitted increasingly thorough analyses of the association of RNA expression with fundamental biology, immunity, pathogenesis, diagnosis, and prognosis. Transcriptomic approaches can now be used to realize a previously unattainable goal, the simultaneous study of RNA expression in host and pathogen, in order to better understand their interactions. This exciting prospect is not without challenges, especially as focus moves from interactions in vitro under tightly controlled conditions to tissue- and systems-level interactions in animal models and natural and experimental infections in humans. Here we review the contribution of transcriptomic studies to the understanding of malaria, a parasitic disease which has exerted a major influence on human evolution and continues to cause a huge global burden of disease. We consider malaria a paradigm for the transcriptomic assessment of systemic host-pathogen interactions in humans, because much of the direct host-pathogen interaction occurs within the blood, a readily sampled compartment of the body. We illustrate lessons learned from transcriptomic studies of malaria and how these lessons may guide studies of host-pathogen interactions in other infectious diseases. We propose that the potential of transcriptomic studies to improve the understanding of malaria as a disease remains partly untapped because of limitations in study design rather than as a consequence of technological constraints. Further advances will require the integration of transcriptomic data with analytical approaches from other scientific disciplines, including epidemiology and mathematical modeling. Copyright © 2018 Lee et al.

Automated identification of protein-ligand interaction features using Inductive Logic Programming: a hexose binding case study.

PubMed

A Santos, Jose C; Nassif, Houssam; Page, David; Muggleton, Stephen H; E Sternberg, Michael J

2012-07-11

There is a need for automated methods to learn general features of the interactions of a ligand class with its diverse set of protein receptors. An appropriate machine learning approach is Inductive Logic Programming (ILP), which automatically generates comprehensible rules in addition to prediction. The development of ILP systems which can learn rules of the complexity required for studies on protein structure remains a challenge. In this work we use a new ILP system, ProGolem, and demonstrate its performance on learning features of hexose-protein interactions. The rules induced by ProGolem detect interactions mediated by aromatics and by planar-polar residues, in addition to less common features such as the aromatic sandwich. The rules also reveal a previously unreported dependency for residues cys and leu. They also specify interactions involving aromatic and hydrogen bonding residues. This paper shows that Inductive Logic Programming implemented in ProGolem can derive rules giving structural features of protein/ligand interactions. Several of these rules are consistent with descriptions in the literature. In addition to confirming literature results, ProGolem's model has a 10-fold cross-validated predictive accuracy that is superior, at the 95% confidence level, to another ILP system previously used to study protein/hexose interactions and is comparable with state-of-the-art statistical learners.

The Effect of Student Collaboration in Solving Physics Problems Using an Online Interactive Response System

ERIC Educational Resources Information Center

Balta, Nuri; Awedh, Mohammad Hamza

2017-01-01

Advanced technology helps educational institutes to improve student learning performance and outcomes. In this study, our aim is to measure and assess student engagement and collaborative learning in engineering classes when using online technology in solving physics problems. The interactive response system used in this study is a collaborative…

A Situated Cultural Festival Learning System Based on Motion Sensing

ERIC Educational Resources Information Center

Chang, Yi-Hsing; Lin, Yu-Kai; Fang, Rong-Jyue; Lu, You-Te

2017-01-01

A situated Chinese cultural festival learning system based on motion sensing is developed in this study. The primary design principle is to create a highly interactive learning environment, allowing learners to interact with Kinect through natural gestures in the designed learning situation to achieve efficient learning. The system has the…

METEOSAT studies of clouds and radiation budget

NASA Technical Reports Server (NTRS)

Saunders, R. W.

1982-01-01

Radiation budget studies of the atmosphere/surface system from Meteosat, cloud parameter determination from space, and sea surface temperature measurements from TIROS N data are all described. This work was carried out on the interactive planetary image processing system (IPIPS), which allows interactive manipulationion of the image data in addition to the conventional computational tasks. The current hardware configuration of IPIPS is shown. The I(2)S is the principal interactive display allowing interaction via a trackball, four buttons under program control, or a touch tablet. Simple image processing operations such as contrast enhancing, pseudocoloring, histogram equalization, and multispectral combinations, can all be executed at the push of a button.

Equilibrium phases of dipolar lattice bosons in the presence of random diagonal disorder

NASA Astrophysics Data System (ADS)

Zhang, C.; Safavi-Naini, A.; Capogrosso-Sansone, B.

2018-01-01

Ultracold gases offer an unprecedented opportunity to engineer disorder and interactions in a controlled manner. In an effort to understand the interplay between disorder, dipolar interactions, and quantum degeneracy, we study two-dimensional hard-core dipolar lattice bosons in the presence of on-site bound disorder. Our results are based on large-scale path-integral quantum Monte Carlo simulations by the worm algorithm. We study the ground-state phase diagram at a fixed half-integer filling factor for which the clean system is either a superfluid at a lower dipolar interaction strength or a checkerboard solid at a larger dipolar interaction strength. We find that, even for weak dipolar interactions, superfluidity is destroyed in favor of a Bose glass at a relatively low disorder strength. Interestingly, in the presence of disorder, superfluidity persists for values of the dipolar interaction strength for which the clean system is a checkerboard solid. At a fixed disorder strength, as the dipolar interaction is increased, superfluidity is destroyed in favor of a Bose glass. As the interaction is further increased, the system eventually develops extended checkerboard patterns in the density distribution. Due to the presence of disorder, though, grain boundaries and defects, responsible for a finite residual compressibility, are present in the density distribution. Finally, we study the robustness of the superfluid phase against thermal fluctuations.

Network Physiology: How Organ Systems Dynamically Interact

PubMed Central

Bartsch, Ronny P.; Liu, Kang K. L.; Bashan, Amir; Ivanov, Plamen Ch.

2015-01-01

We systematically study how diverse physiologic systems in the human organism dynamically interact and collectively behave to produce distinct physiologic states and functions. This is a fundamental question in the new interdisciplinary field of Network Physiology, and has not been previously explored. Introducing the novel concept of Time Delay Stability (TDS), we develop a computational approach to identify and quantify networks of physiologic interactions from long-term continuous, multi-channel physiological recordings. We also develop a physiologically-motivated visualization framework to map networks of dynamical organ interactions to graphical objects encoded with information about the coupling strength of network links quantified using the TDS measure. Applying a system-wide integrative approach, we identify distinct patterns in the network structure of organ interactions, as well as the frequency bands through which these interactions are mediated. We establish first maps representing physiologic organ network interactions and discover basic rules underlying the complex hierarchical reorganization in physiologic networks with transitions across physiologic states. Our findings demonstrate a direct association between network topology and physiologic function, and provide new insights into understanding how health and distinct physiologic states emerge from networked interactions among nonlinear multi-component complex systems. The presented here investigations are initial steps in building a first atlas of dynamic interactions among organ systems. PMID:26555073

Discreteness effects in a reacting system of particles with finite interaction radius.

PubMed

Berti, S; López, C; Vergni, D; Vulpiani, A

2007-09-01

An autocatalytic reacting system with particles interacting at a finite distance is studied. We investigate the effects of the discrete-particle character of the model on properties like reaction rate, quenching phenomenon, and front propagation, focusing on differences with respect to the continuous case. We introduce a renormalized reaction rate depending both on the interaction radius and the particle density, and we relate it to macroscopic observables (e.g., front speed and front thickness) of the system.

Study on intelligent processing system of man-machine interactive garment frame model

NASA Astrophysics Data System (ADS)

Chen, Shuwang; Yin, Xiaowei; Chang, Ruijiang; Pan, Peiyun; Wang, Xuedi; Shi, Shuze; Wei, Zhongqian

2018-05-01

A man-machine interactive garment frame model intelligent processing system is studied in this paper. The system consists of several sensor device, voice processing module, mechanical parts and data centralized acquisition devices. The sensor device is used to collect information on the environment changes brought by the body near the clothes frame model, the data collection device is used to collect the information of the environment change induced by the sensor device, voice processing module is used for speech recognition of nonspecific person to achieve human-machine interaction, mechanical moving parts are used to make corresponding mechanical responses to the information processed by data collection device.it is connected with data acquisition device by a means of one-way connection. There is a one-way connection between sensor device and data collection device, two-way connection between data acquisition device and voice processing module. The data collection device is one-way connection with mechanical movement parts. The intelligent processing system can judge whether it needs to interact with the customer, realize the man-machine interaction instead of the current rigid frame model.

Designing Learning Environments to Teach Interactive Quantum Physics

ERIC Educational Resources Information Center

Puente, Sonia M. Gomez; Swagten, Henk J. M.

2012-01-01

This study aims at describing and analysing systematically an interactive learning environment designed to teach Quantum Physics, a second-year physics course. The instructional design of Quantum Physics is a combination of interactive lectures (using audience response systems), tutorials and self-study in unit blocks, carried out with small…

Effectiveness of Interactive Video to Teach CPR Theory and Skills.

ERIC Educational Resources Information Center

Lyness, Ann L.

This study investigated whether an interactive video system of instruction taught cardiopulmonary resuscitation (CPR) as effectively as traditional instruction. Using standards of the American Heart Association, the study was designed with two randomized groups to be taught either by live instruction or by interactive video. Subjects were 100…

Using Mobile Phones to Increase Classroom Interaction

ERIC Educational Resources Information Center

Cobb, Stephanie; Heaney, Rose; Corcoran, Olivia; Henderson-Begg, Stephanie

2010-01-01

This study examines the possible benefits of using mobile phones to increase interaction and promote active learning in large classroom settings. First year undergraduate students studying Cellular Processes at the University of East London took part in a trial of a new text-based classroom interaction system and evaluated their experience by…

Effects of interactive instructional techniques in a web-based peripheral nervous system component for human anatomy.

PubMed

Allen, Edwin B; Walls, Richard T; Reilly, Frank D

2008-02-01

This study investigated the effects of interactive instructional techniques in a web-based peripheral nervous system (PNS) component of a first year medical school human anatomy course. Existing data from 9 years of instruction involving 856 students were used to determine (1) the effect of web-based interactive instructional techniques on written exam item performance and (2) differences between student opinions of the benefit level of five different types of interactive learning objects used. The interactive learning objects included Patient Case studies, review Games, Simulated Interactive Patients (SIP), Flashcards, and unit Quizzes. Exam item analysis scores were found to be significantly higher (p < 0.05) for students receiving the instructional treatment incorporating the web-based interactive learning objects than for students not receiving this treatment. Questionnaires using a five-point Likert scale were analysed to determine student opinion ratings of the interactive learning objects. Students reported favorably on the benefit level of all learning objects. Students rated the benefit level of the Simulated Interactive Patients (SIP) highest, and this rating was significantly higher (p < 0.05) than all other learning objects. This study suggests that web-based interactive instructional techniques improve student exam performance. Students indicated a strong acceptance of Simulated Interactive Patient learning objects.

Data analysis and interpretation related to space system/environment interactions at LEO altitude

NASA Technical Reports Server (NTRS)

Raitt, W. John; Schunk, Robert W.

1991-01-01

Several studies made on the interaction of active systems with the LEO space environment experienced from orbital or suborbital platforms are covered. The issue of high voltage space interaction is covered by theoretical modeling studies of the interaction of charged solar cell arrays with the ionospheric plasma. The theoretical studies were complemented by experimental measurements made in a vacuum chamber. The other active system studied was the emission of effluent from a space platform. In one study the emission of plasma into the LEO environment was studied by using initially a 2-D model, and then extending this model to 3-D to correctly take account of plasma motion parallel to the geomagnetic field. The other effluent studies related to the releases of neutral gas from an orbiting platform. One model which was extended and used determined the density, velocity, and energy of both an effluent gas and the ambient upper atmospheric gases over a large volume around the platform. This model was adapted to study both ambient and contaminant distributions around smaller objects in the orbital frame of reference with scale sizes of 1 m. The other effluent studies related to the interaction of the released neutral gas with the ambient ionospheric plasma. An electrostatic model was used to help understand anomalously high plasma densities measured at times in the vicinity of the space shuttle orbiter.

Dopamine and dopamine receptor D1 associated with decreased social interaction.

PubMed

Liu, Qiang; Shi, Jieyun; Lin, Rongfei; Wen, Tieqiao

2017-05-01

Deficits in social interaction are hallmarks of neurological and psychiatric disorders. However, its underlying mechanism is still unclear. Here, we show that the loss of dendritic cell factor 1 (Dcf1) in the nervous system of mice induces social interaction deficiency, autism-like behaviour, and influences social interaction via the dopamine system. Dopamine receptor D1 agonist rescues this social cognition phenotype, and improves short-term plasticity. Together, this study presents a new genetic mechanism that affects social interaction and may provide a new way to improve positive social interaction and treat autism spectrum disorders. Copyright © 2017 Elsevier B.V. All rights reserved.

Equilibrium and nonequilibrium properties of Boolean decision problems on scale-free graphs with competing interactions with external biases

NASA Astrophysics Data System (ADS)

Zhu, Zheng; Andresen, Juan Carlos; Janzen, Katharina; Katzgraber, Helmut G.

2013-03-01

We study the equilibrium and nonequilibrium properties of Boolean decision problems with competing interactions on scale-free graphs in a magnetic field. Previous studies at zero field have shown a remarkable equilibrium stability of Boolean variables (Ising spins) with competing interactions (spin glasses) on scale-free networks. When the exponent that describes the power-law decay of the connectivity of the network is strictly larger than 3, the system undergoes a spin-glass transition. However, when the exponent is equal to or less than 3, the glass phase is stable for all temperatures. First we perform finite-temperature Monte Carlo simulations in a field to test the robustness of the spin-glass phase and show, in agreement with analytical calculations, that the system exhibits a de Almeida-Thouless line. Furthermore, we study avalanches in the system at zero temperature to see if the system displays self-organized criticality. This would suggest that damage (avalanches) can spread across the whole system with nonzero probability, i.e., that Boolean decision problems on scale-free networks with competing interactions are fragile when not in thermal equilibrium.

Effect of electron spin-spin interaction on level crossings and spin flips in a spin-triplet system

NASA Astrophysics Data System (ADS)

Jia, Wei; Hu, Fang-Qi; Wu, Ning; Zhao, Qing

2017-12-01

We study level crossings and spin flips in a system consisting of a spin-1 (an electron spin triplet) coupled to a nuclear spin of arbitrary size K , in the presence of a uniform magnetic field and the electron spin-spin interaction within the triplet. Through an analytical diagonalization based on the SU (3 ) Lie algebra, we find that the electron spin-spin interaction not only removes the curious degeneracy which appears in the absence of the interaction, but also produces some level anticrossings (LACs) for strong interactions. The real-time dynamics of the system shows that periodic spin flips occur at the LACs for arbitrary K , which might provide an option for nuclear or electron spin polarization.

Nonequilibrium steady states and resonant tunneling in time-periodically driven systems with interactions

NASA Astrophysics Data System (ADS)

Qin, Tao; Hofstetter, Walter

2018-03-01

Time-periodically driven systems are a versatile toolbox for realizing interesting effective Hamiltonians. Heating, caused by excitations to high-energy states, is a challenge for experiments. While most setups so far address the relatively weakly interacting regime, it is of general interest to study heating in strongly correlated systems. Using Floquet dynamical mean-field theory, we study nonequilibrium steady states (NESS) in the Falicov-Kimball model, with time-periodically driven kinetic energy or interaction. We systematically investigate the nonequilibrium properties of the NESS. For a driven kinetic energy, we show that resonant tunneling, where the interaction is an integer multiple of the driving frequency, plays an important role in the heating. In the strongly correlated regime, we show that this can be well understood using Fermi's golden rule and the Schrieffer-Wolff transformation for a time-periodically driven system. We furthermore demonstrate that resonant tunneling can be used to control the population of Floquet states to achieve "photodoping." For driven interactions introduced by an oscillating magnetic field near a widely adopted Feshbach resonance, we find that the double occupancy is strongly modulated. Our calculations apply to shaken ultracold-atom systems and to solid-state systems in a spatially uniform but time-dependent electric field. They are also closely related to lattice modulation spectroscopy. Our calculations are helpful to understand the latest experiments on strongly correlated Floquet systems.

Improving Vision-Based Motor Rehabilitation Interactive Systems for Users with Disabilities Using Mirror Feedback

PubMed Central

Martínez-Bueso, Pau; Moyà-Alcover, Biel

2014-01-01

Observation is recommended in motor rehabilitation. For this reason, the aim of this study was to experimentally test the feasibility and benefit of including mirror feedback in vision-based rehabilitation systems: we projected the user on the screen. We conducted a user study by using a previously evaluated system that improved the balance and postural control of adults with cerebral palsy. We used a within-subjects design with the two defined feedback conditions (mirror and no-mirror) with two different groups of users (8 with disabilities and 32 without disabilities) using usability measures (time-to-start (T s) and time-to-complete (T c)). A two-tailed paired samples t-test confirmed that in case of disabilities the mirror feedback facilitated the interaction in vision-based systems for rehabilitation. The measured times were significantly worse in the absence of the user's own visual feedback (T s = 7.09 (P < 0.001) and T c = 4.48 (P < 0.005)). In vision-based interaction systems, the input device is the user's own body; therefore, it makes sense that feedback should be related to the body of the user. In case of disabilities the mirror feedback mechanisms facilitated the interaction in vision-based systems for rehabilitation. Results recommends developers and researchers use this improvement in vision-based motor rehabilitation interactive systems. PMID:25295310

Spontaneous emergence of cataclysmic networks in spatially extended systems

NASA Astrophysics Data System (ADS)

Manrubia, Susanna C.; Poyatos, Juan F.; Pérez-Mercader, Juan

2002-11-01

A system of interacting chemical species able to catalyse each others' production is studied. We consider a two-dimensional surface where single molecules attach, diffuse, catalytically interact, and decay. The population of species molecules and the network of interactions among them are dynamical entities. After a short transient time, robust catalytic cycles emerge and a "stationary" state of high diversity and large population numbers settles down. Population dynamics and physical space select among possible graphs of catalytic interactions. The organization of the system is robust: parasitic invaders are short-lived, their populations are kept at low levels, and are unable to sweep away the emerging catalytic cycles.

Metabotropic Glutamate Receptors and Interacting Proteins in Epileptogenesis

PubMed Central

Qian, Feng; Tang, Feng-Ru

2016-01-01

Neurotransmitter and receptor systems are involved in different neurological and neuropsychological disorders such as Parkinson's disease, depression, Alzheimer’s disease and epilepsy. Recent advances in studies of signal transduction pathways or interacting proteins of neurotransmitter receptor systems suggest that different receptor systems may share the common signal transduction pathways or interacting proteins which may be better therapeutic targets for development of drugs to effectively control brain diseases. In this paper, we reviewed metabotropic glutamate receptors (mGluRs) and their related signal transduction pathways or interacting proteins in status epilepticus and temporal lobe epilepsy, and proposed some novel therapeutical drug targets for controlling epilepsy and epileptogenesis. PMID:27030135

Gigantic Dzyaloshinskii-Moriya interaction in the MnBi ultrathin films

NASA Astrophysics Data System (ADS)

Yu, Jie-Xiang; Zang, Jiadong; Zang's Team

The magnetic skyrmion, a swirling-like spin texture with nontrivial topology, is driven by strong Dzyaloshinskii-Moriya (DM) interaction originated from the spin-orbit coupling in inversion symmetry breaking systems. Here, based on first-principles calculations, we predict a new material, MnBi ultrathin film, with gigantic DM interactions. The ratio of the DM interaction to the Heisenberg exchange is about 0.3, exceeding any values reported so far. Its high Curie temperature, high coercivity, and large perpendicular magnetoanisotropy make MnBi a good candidate for future spintronics studies. Topologically nontrivial spin textures are emergent in this system. We expect further experimental efforts will be devoted into this systems.

Comparative study of binding interactions between porphyrin systems and aromatic compounds of biological importance by multiple spectroscopic techniques: A review

NASA Astrophysics Data System (ADS)

Makarska-Bialokoz, Magdalena

2018-07-01

The specific spectroscopic and redox properties of porphyrins predestine them to fulfill the role of sensors during interacting with different biologically active substances. Monitoring of binding interactions in the systems porphyrin-biologically active compound is a key question not only in the field of physiological functions of living organisms, but also in environmental protection, notably in the light of the rapidly growing drug consumption and concurrently the production of drug effluents. Not always beneficial action of drugs on natural porphyrin systems induces to further studies, with commercially available porphyrins as the model systems. Therefore the binding process between several water-soluble porphyrins and a series of biologically active compounds (e.g. caffeine, guanine, theophylline, theobromine, xanthine, uric acid) has been studied in different aqueous solutions analyzing their absorption and steady-state fluorescence spectra, the porphyrin fluorescence lifetimes and their quantum yields. The magnitude of the binding and fluorescence quenching constants values for particular quenchers decreases in a series: uric acid > guanine > caffeine > theophylline > theobromine > xanthine. In all the systems studied there are characters of static quenching, as a consequence of the π-π-stacked non-covalent and non-fluorescent complexes formation between porphyrins and interacting compounds, accompanied simultaneously by the additional specific binding interactions. The porphyrin fluorescence quenching can be explain by the photoinduced intermolecular electron transfer from aromatic compound to the center of the porphyrin molecule, playing the role of the binding site. Presented results can be valuable for designing of new fluorescent porphyrin chemosensors or monitoring of drug traces in aqueous solutions. The obtained outcomes have also the toxicological and medical importance, providing insight into the interactions of the water-soluble porphyrins with biologically active substances.

Universality and critical behavior of the dynamical Mott transition in a system with long-range interactions

DOE PAGES

Rademaker, Louk; Vinokur, Valerii M.; Galda, Alexey

2017-03-16

Here, we study numerically the voltage-induced breakdown of a Mott insulating phase in a system of charged classical particles with long-range interactions. At half-filling on a square lattice this system exhibits Mott localization in the form of a checkerboard pattern. We find universal scaling behavior of the current at the dynamic Mott insulator-metal transition and calculate scaling exponents corresponding to the transition. Our results are in agreement, up to a difference in universality class, with recent experimental evidence of a dynamic Mott transition in a system of interacting superconducting vortices.

Universality and critical behavior of the dynamical Mott transition in a system with long-range interactions.

PubMed

Rademaker, Louk; Vinokur, Valerii M; Galda, Alexey

2017-03-16

We study numerically the voltage-induced breakdown of a Mott insulating phase in a system of charged classical particles with long-range interactions. At half-filling on a square lattice this system exhibits Mott localization in the form of a checkerboard pattern. We find universal scaling behavior of the current at the dynamic Mott insulator-metal transition and calculate scaling exponents corresponding to the transition. Our results are in agreement, up to a difference in universality class, with recent experimental evidence of a dynamic Mott transition in a system of interacting superconducting vortices.

Interaction entropy for protein-protein binding

NASA Astrophysics Data System (ADS)

Sun, Zhaoxi; Yan, Yu N.; Yang, Maoyou; Zhang, John Z. H.

2017-03-01

Protein-protein interactions are at the heart of signal transduction and are central to the function of protein machine in biology. The highly specific protein-protein binding is quantitatively characterized by the binding free energy whose accurate calculation from the first principle is a grand challenge in computational biology. In this paper, we show how the interaction entropy approach, which was recently proposed for protein-ligand binding free energy calculation, can be applied to computing the entropic contribution to the protein-protein binding free energy. Explicit theoretical derivation of the interaction entropy approach for protein-protein interaction system is given in detail from the basic definition. Extensive computational studies for a dozen realistic protein-protein interaction systems are carried out using the present approach and comparisons of the results for these protein-protein systems with those from the standard normal mode method are presented. Analysis of the present method for application in protein-protein binding as well as the limitation of the method in numerical computation is discussed. Our study and analysis of the results provided useful information for extracting correct entropic contribution in protein-protein binding from molecular dynamics simulations.

Measure synchronization in a spin-orbit-coupled bosonic Josephson junction

NASA Astrophysics Data System (ADS)

Wang, Wen-Yuan; Liu, Jie; Fu, Li-Bin

2015-11-01

We present measure synchronization (MS) in a bosonic Josephson junction with spin-orbit coupling. The two atomic hyperfine states are coupled by a Raman dressing scheme, and they are regarded as two orientations of a pseudo-spin-1 /2 system. A feature specific to a spin-orbit-coupled (SOC) bosonic Josephson junction is that the transition from non-MS to MS dynamics can be modulated by Raman laser intensity, even in the absence of interspin atomic interaction. A phase diagram of non-MS and MS dynamics as functions of Raman laser intensity and Josephson tunneling amplitude is presented. Taking into account interspin atomic interactions, the system exhibits MS breaking dynamics resulting from the competition between intraspin and interspin atomic interactions. When interspin atomic interactions dominate in the competition, the system always exhibits MS dynamics. For interspin interaction weaker than intraspin interaction, a window for non-MS dynamics is present. Since SOC Bose-Einstein condensates provide a powerful platform for studies on physical problems in various fields, the study of MS dynamics is valuable in researching the collective coherent dynamical behavior in a spin-orbit-coupled bosonic Josephson junction.

Studying Teacher Selection of Resources in an Ultra-Large Scale Interactive System: Does Metadata Guide the Way?

ERIC Educational Resources Information Center

Abramovich, Samuel; Schunn, Christian

2012-01-01

Ultra-large-scale interactive systems on the Internet have begun to change how teachers prepare for instruction, particularly in regards to resource selection. Consequently, it is important to look at how teachers are currently selecting resources beyond content or keyword search. We conducted a two-part observational study of an existing popular…

The Relationship between the Interactive Computer Interview System and the "Praxis II" Principles of Learning and Teaching Test

ERIC Educational Resources Information Center

Pruett, Sharon M.

2012-01-01

The objective of this study was to compare the relationships between the subtests of the Interactive Computer Interview System and the ETS "Praxis II" Principles of Learning and Teaching examination. In particular, this study compares scores on the ICIS instrument subtests to those gathered from the same classroom teachers on the…

Interaction Between Society and Education in Chicago. Final Report.

ERIC Educational Resources Information Center

Havighurst, Robert J.; And Others

This study of social systems in Chicago has three objectives: (1) To explore the interaction of the educational system with the social structure and social forces in a modern metropolitan area, (2) to make a historical study of the development of education in a city evolving during the 20th century, and (3) to develop a method for a…

The Impact of Transactive Memory System and Interaction Platform in Collaborative Knowledge Construction on Social Presence and Self-Regulation

ERIC Educational Resources Information Center

Yilmaz, Ramazan; Karaoglan Yilmaz, Fatma Gizem; Kilic Cakmak, Ebru

2017-01-01

The purpose of this study is to examine the impacts of transactive memory system (TMS) and interaction platforms in computer-supported collaborative learning (CSCL) on social presence perceptions and self-regulation skills of learners. Within the scope of the study, social presence perceptions and self-regulation skills of students in…

The Effectiveness of Using Cloud-Based Cross-Device IRS to Support Classical Chinese Learning

ERIC Educational Resources Information Center

Wang, Yi-Hsuan

2017-01-01

The purpose of the present study was to examine the effects of integrating a cloud-based cross-device interactive response system (CCIRS) on enhancing students' classical Chinese learning. The system is a cloud-based IRS system which provides instructors and learners with an environment in which to achieve immediate interactive learning and…

Monitoring protein-protein interactions using split synthetic renilla luciferase protein-fragment-assisted complementation.

PubMed

Paulmurugan, R; Gambhir, S S

2003-04-01

In this study we developed an inducible synthetic renilla luciferase protein-fragment-assisted complementation-based bioluminescence assay to quantitatively measure real time protein-protein interactions in mammalian cells. We identified suitable sites to generate fragments of N and C portions of the protein that yield significant recovered activity through complementation. We validate complementation-based activation of split synthetic renilla luciferase protein driven by the interaction of two strongly interacting proteins, MyoD and Id, in five different cell lines utilizing transient transfection studies. The expression level of the system was also modulated by tumor necrosis factor alpha through NFkappaB-promoter/enhancer elements used to drive expression of the N portion of synthetic renilla luciferase reporter gene. This new system should help in studying protein-protein interactions and when used with other split reporters (e.g., split firefly luciferase) should help to monitor different components of an intracellular network.

Monitoring Protein–Protein Interactions Using Split Synthetic Renilla Luciferase Protein-Fragment-Assisted Complementation

PubMed Central

Paulmurugan, R.; Gambhir, S. S.

2014-01-01

In this study we developed an inducible synthetic renilla luciferase protein-fragment-assisted complementation-based bioluminescence assay to quantitatively measure real time protein–protein interactions in mammalian cells. We identified suitable sites to generate fragments of N and C portions of the protein that yield significant recovered activity through complementation. We validate complementation-based activation of split synthetic renilla luciferase protein driven by the interaction of two strongly interacting proteins, MyoD and Id, in five different cell lines utilizing transient transfection studies. The expression level of the system was also modulated by tumor necrosis factor α through NFκB-promoter/enhancer elements used to drive expression of the N portion of synthetic renilla luciferase reporter gene. This new system should help in studying protein–protein interactions and when used with other split reporters (e.g., split firefly luciferase) should help to monitor different components of an intracellular network. PMID:12705589

Describing the complexity of systems: multivariable "set complexity" and the information basis of systems biology.

PubMed

Galas, David J; Sakhanenko, Nikita A; Skupin, Alexander; Ignac, Tomasz

2014-02-01

Context dependence is central to the description of complexity. Keying on the pairwise definition of "set complexity," we use an information theory approach to formulate general measures of systems complexity. We examine the properties of multivariable dependency starting with the concept of interaction information. We then present a new measure for unbiased detection of multivariable dependency, "differential interaction information." This quantity for two variables reduces to the pairwise "set complexity" previously proposed as a context-dependent measure of information in biological systems. We generalize it here to an arbitrary number of variables. Critical limiting properties of the "differential interaction information" are key to the generalization. This measure extends previous ideas about biological information and provides a more sophisticated basis for the study of complexity. The properties of "differential interaction information" also suggest new approaches to data analysis. Given a data set of system measurements, differential interaction information can provide a measure of collective dependence, which can be represented in hypergraphs describing complex system interaction patterns. We investigate this kind of analysis using simulated data sets. The conjoining of a generalized set complexity measure, multivariable dependency analysis, and hypergraphs is our central result. While our focus is on complex biological systems, our results are applicable to any complex system.

Molecular insight into the enhancement of benzene-carbon nanotube interactions by surface modification for drug delivery systems (DDS)

NASA Astrophysics Data System (ADS)

Zhao, Jianghao; Liu, Xiaoshan; Zhu, Zhu; Wang, Ning; Sun, Wenjing; Chen, Congmei; He, Zhiwei

2017-09-01

Anthracyclines are effective anticancer drugs but have drawbacks including systemic toxicity and drug resistance. Delivering them directly to the tumor may improve therapeutic efficacy and reduce adverse effects. Carbon nanotubes (CNTs) can act as excellent drug delivery systems (DDS), but pristine CNTs have inert surfaces, which contributes poor drug loading capacity and limits dispersion. In this study, we designed a series of functionalized CNTs (f-CNTs) with anchored hydrophilic groups (OH, COOH, and NH2) by substitutional doping of the CNT lattice (DNT) using N or B atoms or the combination of both. The aromatic compound benzene (Ben) was selected as a model for anthracycline drugs. The effect of CNT curvature, chemical groups (CGs), and doping on the Ben-CNTs interactions was studied using quantum chemistry calculations. Our results show that π-π interactions between Ben and CNTs are influenced by CNT curvature. When the CNTs were functionalized only with CGs and not doped, the system was unstable, resulting in weak Ben-CNT interactions. However, anchoring CGs on DNTs greatly enhanced the Ben-CNT interactions. CNTs with good affinity for drug molecules, improved solubility, and lower tendency to aggregate have potential as DDS for enhancing the efficacy of medicines. We believe that these studies have general applicability and anticipate that our findings will motivate additional theoretical and experimental studies on the biology and chemistry of CNTs as DDS.

Increasing productivity by matching farming system management and genotype in water-limited environments.

PubMed

Kirkegaard, J A; Hunt, J R

2010-10-01

Improvements in water productivity and yield arise from interactions between varieties (G) and their management (M). Most G×M interactions considered by breeders and physiologists focus on in-crop management (e.g. sowing time, plant density, N management). However, opportunities exist to capture more water and use it more effectively that involve judicious management of prior crops and fallows (e.g. crop sequence, weed control, residue management). The dry-land wheat production system of southern Australia, augmented by simulation studies, is used to demonstrate the relative impacts and interactions of a range of pre-crop and in-crop management decisions on water productivity. A specific case study reveals how a novel genetic trait, long coleoptiles that enable deeper sowing, can interact with different management options to increase the water-limited yield of wheat from 1.6 t ha(-1) to 4.5 t ha(-1), reflecting the experience of leading growers. Understanding such interactions will be necessary to capture benefits from new varieties within the farming systems of the future.

Ghosts, UFOs, and magic: positive affect and the experiential system.

PubMed

King, Laura A; Burton, Chad M; Hicks, Joshua A; Drigotas, Stephen M

2007-05-01

Three studies examined the potential interactions of the experiential system and positive affect (PA) in predicting superstitious beliefs and sympathetic magic. In Study 1, experientiality and induced positive mood interacted to predict the emergence of belief in videos purporting to show unidentified flying objects or ghosts. In Study 2, naturally occurring PA interacted with experientiality to predict susceptibility to sympathetic magic, specifically difficulty in throwing darts at a picture of a baby (demonstrating the law of similarity). In Study 3, induced mood interacted with experientiality to predict sitting farther away from, and expressing less liking for, a partner who had stepped in excrement (demonstrating the law of contagion). Results are interpreted as indicating that PA promotes experiential processing. Implications for the psychology of nonrational beliefs and behaviors are discussed. ((c) 2007 APA, all rights reserved).

Synchronization in human musical rhythms and mutually interacting complex systems

PubMed Central

Hennig, Holger

2014-01-01

Though the music produced by an ensemble is influenced by multiple factors, including musical genre, musician skill, and individual interpretation, rhythmic synchronization is at the foundation of musical interaction. Here, we study the statistical nature of the mutual interaction between two humans synchronizing rhythms. We find that the interbeat intervals of both laypeople and professional musicians exhibit scale-free (power law) cross-correlations. Surprisingly, the next beat to be played by one person is dependent on the entire history of the other person’s interbeat intervals on timescales up to several minutes. To understand this finding, we propose a general stochastic model for mutually interacting complex systems, which suggests a physiologically motivated explanation for the occurrence of scale-free cross-correlations. We show that the observed long-term memory phenomenon in rhythmic synchronization can be imitated by fractal coupling of separately recorded or synthesized audio tracks and thus applied in electronic music. Though this study provides an understanding of fundamental characteristics of timing and synchronization at the interbrain level, the mutually interacting complex systems model may also be applied to study the dynamics of other complex systems where scale-free cross-correlations have been observed, including econophysics, physiological time series, and collective behavior of animal flocks. PMID:25114228

Frustrated Magnetism in Low-Dimensional Lattices

NASA Astrophysics Data System (ADS)

Tovar, Mayra

2011-12-01

In this dissertation we present the results of a theoretical investigation of spin models on two-dimensional and quasi one-dimensional lattices, all unified under the concept of quantum frustrated antiferromagnetism, and all discussing various aspects of the antiferromagnetic Heisenberg model on the kagome lattice. In the Introduction (Chapter 1), we discuss at some length such concepts as frustration and superexchange, among others, which are of common relevance in the rest of the chapters. In Chapter 2, we study the effect of Dzyaloshinskii-Moriya (DM) interactions on the zero-temperature magnetic susceptibility of systems whose low energy can be described by short-range valence bond states. Our work shows that this treatment is consistent with the experimentally observed non-vanishing susceptibility---in the specified temperature limit---of the spin-1/2 kagome antiferromagnetic compound ZnCu3(OH)6Cl2, also known as herbertsmithite. Although the objective of this work is explaining the aforementioned characteristic of the experimental system, our methods are more general and we apply them to the checkerboard and Shastry-Sutherland lattices as well. In Chapter 3, we discuss our findings in the study of ghost-mediated domain wall interactions in the diamondback ladder. These domain walls are the the spin excitations---the kinks and the antikinks---separating the ground states along one chain of the ladder. While as individual entities an antikink is energy costly and a kink energy free, our study finds that both interact via the ghosts that they produce in the opposite side of the ladder from where they are located. Through the study of these ghosts, we find that domain walls proliferate in the system above a critical value of the system's coupling constants. It is this proliferation that makes their treatment as free, non-interacting particles impossible, so we study here their interactions both quantitatively and qualitatively, in a region where the latter are yet not very strong, namely below the critical point. Based on the calculated two-body interaction potential, domain walls interact attractively (repulsively) when separated at even (odd) distances, with a strength that decays as 1/sp, where s is their separation and p<1. We also consider higher-order interactions. In the last chapter, Chapter 4, we present our study of the spin-1 kagome Heisenberg antiferromagnet. Our approach is to first consider an SU(2)-symmetric parent Hamiltonian with known ground states on the S=1 kagome lattice, in which nearest-neighbor Heisenberg interactions are already present. We then enhance these interactions by an additional Heisenberg term added perturbatively in order to move the system closer to a pure Heisenberg antiferromagnet. The results of this enhancement is obtaining a description of the system in terms of an effective Hamiltonian, namely a transverse field Ising AF on the triangular lattice. Based on the particular values of this effective Hamiltonian, our system is found to be in the order-by-disorder phase.

Nonlinear dynamics of global atmospheric and earth system processes

NASA Technical Reports Server (NTRS)

Zhang, Taiping; Verbitsky, Mikhail; Saltzman, Barry; Mann, Michael E.; Park, Jeffrey; Lall, Upmanu

1995-01-01

During the grant period, the authors continued ongoing studies aimed at enhancing their understanding of the operation of the atmosphere as a complex nonlinear system interacting with the hydrosphere, biosphere, and cryosphere in response to external radiative forcing. Five papers were completed with support from the grant, representing contributions in three main areas of study: (1) theoretical studies of the interactive atmospheric response to changed biospheric boundary conditions measurable from satellites; (2) statistical-observational studies of global-scale temperature variability on interannual to century time scales; and (3) dynamics of long-term earth system changes associated with ice sheet surges.

Self assembly of anisotropic colloidal particles

NASA Astrophysics Data System (ADS)

Florea, Daniel; Wyss, Hans

2012-02-01

Colloidal particles have been successfully used as ''model atoms'', as their behavior can be more directly studied than that of atoms or molecules by direct imaging in a confocal microscope. Most studies have focussed on spherical particles with isotropic interactions. However, a range of interesting materials such as many supramolecular polymers or biopolymers exhibit highly directional interactions. To capture their behavior in colloidal model systems, particles with anisotropic interactions are clearly required. Here we use a colloidal system of nonspherical colloids, where highly directional interactions can be induced via depletion. By biaxially stretching spherical PMMA particles we create oblate spheroidal particles. We induce attractive interactions between these particles by adding a non-adsorbing polymer to the background liquid. The resulting depletion interaction is stronger along the minor axis of the oblate spheroids. We study the phase behavior of these materials as a function of the ellipsoid aspect ratio, the strength of the depletion interactions, and the particle concentration. The resulting morphologies are qualitatively different from those observed with spherical particles. This can be exploited for creating new materials with tailored structures.

A formulation to analyze system-of-systems problems: A case study of airport metroplex operations

NASA Astrophysics Data System (ADS)

Ayyalasomayajula, Sricharan Kishore

A system-of-systems (SoS) can be described as a collection of multiple, heterogeneous, distributed, independent components interacting to achieve a range of objectives. A generic formulation was developed to model component interactions in an SoS to understand their influence on overall SoS performance. The formulation employs a lexicon to aggregate components into hierarchical interaction networks and understand how their topological properties affect the performance of the aggregations. Overall SoS performance is evaluated by monitoring the changes in stakeholder profitability due to changes in component interactions. The formulation was applied to a case study in air transportation focusing on operations at airport metroplexes. Metroplexes are geographical regions with two or more airports in close proximity to one another. The case study explored how metroplex airports interact with one another, what dependencies drive these interactions, and how these dependencies affect metroplex throughput and capacity. Metrics were developed to quantify runway dependencies at a metroplex and were correlated with its throughput and capacity. Operations at the New York/New Jersey metroplex (NYNJ) airports were simulated to explore the feasibility of operating very large aircraft (VLA), such as the Airbus A380, as a delay-mitigation strategy at these airports. The proposed formulation was employed to analyze the impact of this strategy on different stakeholders in the national air transportation system (ATS), such as airlines and airports. The analysis results and their implications were used to compare the pros and cons of operating VLAs at NYNJ from the perspectives of airline profitability, and flight delays at NYNJ and across the ATS.

Is There Any Preferential Interaction of Ions of Ionic Liquids with DMSO and H2O? A Comparative Study from MD Simulation.

PubMed

Zhao, Yuling; Wang, Jianji; Wang, Huiyong; Li, Zhiyong; Liu, Xiaomin; Zhang, Suojiang

2015-06-04

Recently, some binary ionic liquid (IL)/cosolvent systems have shown better performance than the pure ILs in fields such as CO2 absorption, catalysis, cellulose dissolution, and electrochemistry. However, interactions of ILs with cosolvents are still not well understood at the molecular level. In this work, H2O and DMSO were chosen as the representative protic and aprotic solvents to study the effect of cosolvent nature on solvation of a series of ILs by molecular dynamics simulations and quantum chemistry calculations. The concept of preferential interaction of ions was proposed to describe the interaction of cosolvent with cation and anion of the ILs. By comparing the interaction energies between IL and different cosolvents, it was found that there were significantly preferential interactions of anions of the ILs with water, but the same was not true for the interactions of cations/anions of the ILs with DMSO. Then, a detailed analysis and comparison of the interactions in IL/cosolvent systems, hydrogen bonds between cations and anions of the ILs, and the structure of the first coordination shells of the cations and the anions were performed to reveal the existing state of ions at different molar ratios of the cosolvent to a given IL. Furthermore, a systematic knowledge for the solvation of ions of the ILs in DMSO was given to understand cellulose dissolution in IL/cosolvent systems. The conclusions drawn from this study may provide new insight into the ionic solvation of ILs in cosolvents, and motivate further studies in the related applications.

A meta-analysis of in-vehicle and nomadic voice-recognition system interaction and driving performance.

PubMed

Simmons, Sarah M; Caird, Jeff K; Steel, Piers

2017-09-01

Driver distraction is a growing and pervasive issue that requires multiple solutions. Voice-recognition (V-R) systems may decrease the visual-manual (V-M) demands of a wide range of in-vehicle system and smartphone interactions. However, the degree that V-R systems integrated into vehicles or available in mobile phone applications affect driver distraction is incompletely understood. A comprehensive meta-analysis of experimental studies was conducted to address this knowledge gap. To meet study inclusion criteria, drivers had to interact with a V-R system while driving and doing everyday V-R tasks such as dialing, initiating a call, texting, emailing, destination entry or music selection. Coded dependent variables included detection, reaction time, lateral position, speed and headway. Comparisons of V-R systems with baseline driving and/or a V-M condition were also coded. Of 817 identified citations, 43 studies involving 2000 drivers and 183 effect sizes (r) were analyzed in the meta-analysis. Compared to baseline, driving while interacting with a V-R system is associated with increases in reaction time and lane positioning, and decreases in detection. When V-M systems were compared to V-R systems, drivers had slightly better performance with the latter system on reaction time, lane positioning and headway. Although V-R systems have some driving performance advantages over V-M systems, they have a distraction cost relative to driving without any system at all. The pattern of results indicates that V-R systems impose moderate distraction costs on driving. In addition, drivers minimally engage in compensatory performance adjustments such as reducing speed and increasing headway while using V-R systems. Implications of the results for theory, design guidelines and future research are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nanoscale control of competing interactions and geometrical frustration in a dipolar trident lattice.

PubMed

Farhan, Alan; Petersen, Charlotte F; Dhuey, Scott; Anghinolfi, Luca; Qin, Qi Hang; Saccone, Michael; Velten, Sven; Wuth, Clemens; Gliga, Sebastian; Mellado, Paula; Alava, Mikko J; Scholl, Andreas; van Dijken, Sebastiaan

2017-10-17

Geometrical frustration occurs when entities in a system, subject to given lattice constraints, are hindered to simultaneously minimize their local interactions. In magnetism, systems incorporating geometrical frustration are fascinating, as their behavior is not only hard to predict, but also leads to the emergence of exotic states of matter. Here, we provide a first look into an artificial frustrated system, the dipolar trident lattice, where the balance of competing interactions between nearest-neighbor magnetic moments can be directly controlled, thus allowing versatile tuning of geometrical frustration and manipulation of ground state configurations. Our findings not only provide the basis for future studies on the low-temperature physics of the dipolar trident lattice, but also demonstrate how this frustration-by-design concept can deliver magnetically frustrated metamaterials.Artificial magnetic nanostructures enable the study of competing frustrated interactions with more control over the system parameters than is possible in magnetic materials. Farhan et al. present a two-dimensional lattice geometry where the frustration can be controlled by tuning the unit cell parameters.

User Localization During Human-Robot Interaction

PubMed Central

Alonso-Martín, F.; Gorostiza, Javi F.; Malfaz, María; Salichs, Miguel A.

2012-01-01

This paper presents a user localization system based on the fusion of visual information and sound source localization, implemented on a social robot called Maggie. One of the main requisites to obtain a natural interaction between human-human and human-robot is an adequate spatial situation between the interlocutors, that is, to be orientated and situated at the right distance during the conversation in order to have a satisfactory communicative process. Our social robot uses a complete multimodal dialog system which manages the user-robot interaction during the communicative process. One of its main components is the presented user localization system. To determine the most suitable allocation of the robot in relation to the user, a proxemic study of the human-robot interaction is required, which is described in this paper. The study has been made with two groups of users: children, aged between 8 and 17, and adults. Finally, at the end of the paper, experimental results with the proposed multimodal dialog system are presented. PMID:23012577

User localization during human-robot interaction.

PubMed

Alonso-Martín, F; Gorostiza, Javi F; Malfaz, María; Salichs, Miguel A

2012-01-01

This paper presents a user localization system based on the fusion of visual information and sound source localization, implemented on a social robot called Maggie. One of the main requisites to obtain a natural interaction between human-human and human-robot is an adequate spatial situation between the interlocutors, that is, to be orientated and situated at the right distance during the conversation in order to have a satisfactory communicative process. Our social robot uses a complete multimodal dialog system which manages the user-robot interaction during the communicative process. One of its main components is the presented user localization system. To determine the most suitable allocation of the robot in relation to the user, a proxemic study of the human-robot interaction is required, which is described in this paper. The study has been made with two groups of users: children, aged between 8 and 17, and adults. Finally, at the end of the paper, experimental results with the proposed multimodal dialog system are presented.

Prethermal time crystals in a one-dimensional periodically driven Floquet system

NASA Astrophysics Data System (ADS)

Zeng, Tian-Sheng; Sheng, D. N.

2017-09-01

Motivated by experimental observations of time-symmetry breaking behavior in a periodically driven (Floquet) system, we study a one-dimensional spin model to explore the stability of such Floquet discrete time crystals (DTCs) under the interplay between interaction and the microwave driving. For intermediate interactions and high drivings, from the time evolution of both stroboscopic spin polarization and mutual information between two ends, we show that Floquet DTCs can exist in a prethermal time regime without the tuning of strong disorder. For much weak interactions the system is a symmetry-unbroken phase, while for strong interactions it gives its way to a thermal phase. Through analyzing the entanglement dynamics, we show that large driving fields protect the prethermal DTCs from many-body localization and thermalization. Our results suggest that by increasing the spin interaction, one can drive the experimental system into optimal regime for observing a robust prethermal DTC phase.

Mutual influence between triel bond and cation-π interactions: an ab initio study

NASA Astrophysics Data System (ADS)

Esrafili, Mehdi D.; Mousavian, Parisasadat

2017-12-01

Using ab initio calculations, the cooperative and solvent effects on cation-π and B...N interactions are studied in some model ternary complexes, where these interactions coexist. The nature of the interactions and the mechanism of cooperativity are investigated by means of quantum theory of atoms in molecules (QTAIM), noncovalent interaction (NCI) index and natural bond orbital analysis. The results indicate that all cation-π and B...N binding distances in the ternary complexes are shorter than those of corresponding binary systems. The QTAIM analysis reveals that ternary complexes have higher electron density at their bond critical points relative to the corresponding binary complexes. In addition, according to the QTAIM analysis, the formation of cation-π interaction increases covalency of B...N bonds. The NCI analysis indicates that the cooperative effects in the ternary complexes make a shift in the location of the spike associated with each interaction, which can be regarded as an evidence for the reinforcement of both cation-π and B...N interactions in these systems. Solvent effects on the cooperativity of cation-π and B...N interactions are also investigated.

Kinetic Models for Topological Nearest-Neighbor Interactions

NASA Astrophysics Data System (ADS)

Blanchet, Adrien; Degond, Pierre

2017-12-01

We consider systems of agents interacting through topological interactions. These have been shown to play an important part in animal and human behavior. Precisely, the system consists of a finite number of particles characterized by their positions and velocities. At random times a randomly chosen particle, the follower, adopts the velocity of its closest neighbor, the leader. We study the limit of a system size going to infinity and, under the assumption of propagation of chaos, show that the limit kinetic equation is a non-standard spatial diffusion equation for the particle distribution function. We also study the case wherein the particles interact with their K closest neighbors and show that the corresponding kinetic equation is the same. Finally, we prove that these models can be seen as a singular limit of the smooth rank-based model previously studied in Blanchet and Degond (J Stat Phys 163:41-60, 2016). The proofs are based on a combinatorial interpretation of the rank as well as some concentration of measure arguments.

Cognitive rehabilitation system for children with autism spectrum disorder using serious games: A pilot study.

PubMed

Aresti-Bartolome, Nuria; Garcia-Zapirain, Begonya

2015-01-01

This paper studies and assesses how rehabilitation activities and supervised computer games incorporated into a system aimed at people diagnosed with Autism Spectrum Disorder (ASD) can be used to work on the areas affected by ASD at any time and in any place. This research specifically assesses the areas that affect communication and interaction between people with ASD and professionals. In order to do this, a group of 20 children diagnosed with ASD of between 3 and 8 years old (clinical group) was used, together with a group of 20 children of between 3 and 8 years old with a neurotypical development, which served as a control group. During the tests, response time and visual interaction with the session leader were evaluated. Despite the fact that the clinical group spent more time (M = 21.08 sec) than the control group (M = 4.52) to interact leader, eye contact predominated in the interaction. As a result of the pilot study, the system obtained could help in cognitive rehabilitation.

Emergence of liquid crystalline order in the lowest Landau level of a quantum Hall system with internal anisotropy

NASA Astrophysics Data System (ADS)

Ciftja, Orion

2018-05-01

It has now become evident that interplay between internal anisotropy parameters (such as electron mass anisotropy and/or anisotropic coupling of electrons to the substrate) and electron-electron correlation effects can create a rich variety of possibilities especially in quantum Hall systems. The electron mass anisotropy or material substrate effects (for example, the piezoelectric effect in GaAs) can lead to an effective anisotropic interaction potential between electrons. For lack of knowledge of realistic ab-initio potentials that may describe such effects, we adopt a phenomenological approach and assume that an anisotropic Coulomb interaction potential mimics the internal anisotropy of the system. In this work we investigate the emergence of liquid crystalline order at filling factor ν = 1/6 of the lowest Landau level, a state very close to the point where a transition from the liquid to the Wigner solid happens. We consider small finite systems of electrons interacting with an anisotropic Coulomb interaction potential and study the energy stability of an anisotropic liquid crystalline state relative to its isotropic Fermi-liquid counterpart. Quantum Monte Carlo simulation results in disk geometry show stabilization of liquid crystalline order driven by an anisotropic Coulomb interaction potential at all values of the interaction anisotropy parameter studied.

A comparative study of multivariable robustness analysis methods as applied to integrated flight and propulsion control

NASA Technical Reports Server (NTRS)

Schierman, John D.; Lovell, T. A.; Schmidt, David K.

1993-01-01

Three multivariable robustness analysis methods are compared and contrasted. The focus of the analysis is on system stability and performance robustness to uncertainty in the coupling dynamics between two interacting subsystems. Of particular interest is interacting airframe and engine subsystems, and an example airframe/engine vehicle configuration is utilized in the demonstration of these approaches. The singular value (SV) and structured singular value (SSV) analysis methods are compared to a method especially well suited for analysis of robustness to uncertainties in subsystem interactions. This approach is referred to here as the interacting subsystem (IS) analysis method. This method has been used previously to analyze airframe/engine systems, emphasizing the study of stability robustness. However, performance robustness is also investigated here, and a new measure of allowable uncertainty for acceptable performance robustness is introduced. The IS methodology does not require plant uncertainty models to measure the robustness of the system, and is shown to yield valuable information regarding the effects of subsystem interactions. In contrast, the SV and SSV methods allow for the evaluation of the robustness of the system to particular models of uncertainty, and do not directly indicate how the airframe (engine) subsystem interacts with the engine (airframe) subsystem.

Adaptation of Tri-molecular fluorescence complementation allows assaying of regulatory Csr RNA-protein interactions in bacteria.

PubMed

Gelderman, Grant; Sivakumar, Anusha; Lipp, Sarah; Contreras, Lydia

2015-02-01

sRNAs play a significant role in controlling and regulating cellular metabolism. One of the more interesting aspects of certain sRNAs is their ability to make global changes in the cell by interacting with regulatory proteins. In this work, we demonstrate the use of an in vivo Tri-molecular Fluorescence Complementation assay to detect and visualize the central regulatory sRNA-protein interaction of the Carbon Storage Regulatory system in E. coli. The Carbon Storage Regulator consists primarily of an RNA binding protein, CsrA, that alters the activity of mRNA targets and of an sRNA, CsrB, that modulates the activity of CsrA. We describe the construction of a fluorescence complementation system that detects the interactions between CsrB and CsrA. Additionally, we demonstrate that the intensity of the fluorescence of this system is able to detect changes in the affinity of the CsrB-CsrA interaction, as caused by mutations in the protein sequence of CsrA. While previous methods have adopted this technique to study mRNA or RNA localization, this is the first attempt to use this technique to study the sRNA-protein interaction directly in bacteria. This method presents a potentially powerful tool to study complex bacterial RNA protein interactions in vivo. © 2014 Wiley Periodicals, Inc.

Automated identification of protein-ligand interaction features using Inductive Logic Programming: a hexose binding case study

PubMed Central

2012-01-01

Background There is a need for automated methods to learn general features of the interactions of a ligand class with its diverse set of protein receptors. An appropriate machine learning approach is Inductive Logic Programming (ILP), which automatically generates comprehensible rules in addition to prediction. The development of ILP systems which can learn rules of the complexity required for studies on protein structure remains a challenge. In this work we use a new ILP system, ProGolem, and demonstrate its performance on learning features of hexose-protein interactions. Results The rules induced by ProGolem detect interactions mediated by aromatics and by planar-polar residues, in addition to less common features such as the aromatic sandwich. The rules also reveal a previously unreported dependency for residues cys and leu. They also specify interactions involving aromatic and hydrogen bonding residues. This paper shows that Inductive Logic Programming implemented in ProGolem can derive rules giving structural features of protein/ligand interactions. Several of these rules are consistent with descriptions in the literature. Conclusions In addition to confirming literature results, ProGolem’s model has a 10-fold cross-validated predictive accuracy that is superior, at the 95% confidence level, to another ILP system previously used to study protein/hexose interactions and is comparable with state-of-the-art statistical learners. PMID:22783946

Spectra, current flow, and wave-function morphology in a model PT -symmetric quantum dot with external interactions

NASA Astrophysics Data System (ADS)

Tellander, Felix; Berggren, Karl-Fredrik

2017-04-01

In this paper we use numerical simulations to study a two-dimensional (2D) quantum dot (cavity) with two leads for passing currents (electrons, photons, etc.) through the system. By introducing an imaginary potential in each lead the system is made symmetric under parity-time inversion (PT symmetric). This system is experimentally realizable in the form of, e.g., quantum dots in low-dimensional semiconductors, optical and electromagnetic cavities, and other classical wave analogs. The computational model introduced here for studying spectra, exceptional points (EPs), wave-function symmetries and morphology, and current flow includes thousands of interacting states. This supplements previous analytic studies of few interacting states by providing more detail and higher resolution. The Hamiltonian describing the system is non-Hermitian; thus, the eigenvalues are, in general, complex. The structure of the wave functions and probability current densities are studied in detail at and in between EPs. The statistics for EPs is evaluated, and reasons for a gradual dynamical crossover are identified.

Teacher-Child Interactions in Chile and Their Associations with Prekindergarten Outcomes

ERIC Educational Resources Information Center

Leyva, Diana; Weiland, Christina; Barata, M.; Yoshikawa, Hirokazu; Snow, Catherine; Treviño, Ernesto; Rolla, Andrea

2015-01-01

Quality of teacher-child interactions is central to prekindergarten children's learning. In the United States, the quality of teacher-child interactions is commonly assessed using the teaching through interactions conceptual framework and an associated observational tool, the Classroom Assessment Scoring System (CLASS). This study examined: (a)…

Controlling the transmitted information of a multi-photon interacting with a single-Cooper pair box

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kadry, Heba, E-mail: hkadry1@yahoo.com; Abdel-Aty, Abdel-Haleem, E-mail: hkadry1@yahoo.com; Zakaria, Nordin, E-mail: hkadry1@yahoo.com

2014-10-24

We study a model of a multi-photon interaction of a single Cooper pair box with a cavity field. The exchange of the information using this system is studied. We quantify the fidelity of the transmitted information. The effect of the system parameters (detuning parameter, field photons, state density and mean photon number) in the fidelity of the transmitted information is investigated. We found that the fidelity of the transmitted information can be controlled using the system parameters.

Interaction Dynamics Between a Flexible Rotor and an Auxiliary Clearance Bearing

NASA Technical Reports Server (NTRS)

Lawen, James L., Jr.; Flowers, George T.

1996-01-01

This study investigates the application of synchronous interaction dynamics methodology to the design of auxiliary bearing systems. The technique is applied to a flexible rotor system and comparisons are made between the behavior predicted by this analysis method and the observed simulation response characteristics. Of particular interest is the influence of coupled shaft/bearing vibration modes on rotordynamical behavior. Experimental studies are also perFormed to validate the simulation results and provide insight into the expected behavior of such a system.

Modal interaction in linear dynamic systems near degenerate modes

NASA Technical Reports Server (NTRS)

Afolabi, D.

1991-01-01

In various problems in structural dynamics, the eigenvalues of a linear system depend on a characteristic parameter of the system. Under certain conditions, two eigenvalues of the system approach each other as the characteristic parameter is varied, leading to modal interaction. In a system with conservative coupling, the two eigenvalues eventually repel each other, leading to the curve veering effect. In a system with nonconservative coupling, the eigenvalues continue to attract each other, eventually colliding, leading to eigenvalue degeneracy. Modal interaction is studied in linear systems with conservative and nonconservative coupling using singularity theory, sometimes known as catastrophe theory. The main result is this: eigenvalue degeneracy is a cause of instability; in systems with conservative coupling, it induces only geometric instability, whereas in systems with nonconservative coupling, eigenvalue degeneracy induces both geometric and elastic instability. Illustrative examples of mechanical systems are given.

Bridging the gap between modules in isolation and as part of networks: A systems framework for elucidating interaction and regulation of signalling modules

NASA Astrophysics Data System (ADS)

Menon, Govind; Krishnan, J.

2016-07-01

While signalling and biochemical modules have been the focus of numerous studies, they are typically studied in isolation, with no examination of the effects of the ambient network. In this paper we formulate and develop a systems framework, rooted in dynamical systems, to understand such effects, by studying the interaction of signalling modules. The modules we consider are (i) basic covalent modification, (ii) monostable switches, (iii) bistable switches, (iv) adaptive modules, and (v) oscillatory modules. We systematically examine the interaction of these modules by analyzing (a) sequential interaction without shared components, (b) sequential interaction with shared components, and (c) oblique interactions. Our studies reveal that the behaviour of a module in isolation may be substantially different from that in a network, and explicitly demonstrate how the behaviour of a given module, the characteristics of the ambient network, and the possibility of shared components can result in new effects. Our global approach illuminates different aspects of the structure and functioning of modules, revealing the importance of dynamical characteristics as well as biochemical features; this provides a methodological platform for investigating the complexity of natural modules shaped by evolution, elucidating the effects of ambient networks on a module in multiple cellular contexts, and highlighting the capabilities and constraints for engineering robust synthetic modules. Overall, such a systems framework provides a platform for bridging the gap between non-linear information processing modules, in isolation and as parts of networks, and a basis for understanding new aspects of natural and engineered cellular networks.

Bridging the gap between modules in isolation and as part of networks: A systems framework for elucidating interaction and regulation of signalling modules.

PubMed

Menon, Govind; Krishnan, J

2016-07-21

While signalling and biochemical modules have been the focus of numerous studies, they are typically studied in isolation, with no examination of the effects of the ambient network. In this paper we formulate and develop a systems framework, rooted in dynamical systems, to understand such effects, by studying the interaction of signalling modules. The modules we consider are (i) basic covalent modification, (ii) monostable switches, (iii) bistable switches, (iv) adaptive modules, and (v) oscillatory modules. We systematically examine the interaction of these modules by analyzing (a) sequential interaction without shared components, (b) sequential interaction with shared components, and (c) oblique interactions. Our studies reveal that the behaviour of a module in isolation may be substantially different from that in a network, and explicitly demonstrate how the behaviour of a given module, the characteristics of the ambient network, and the possibility of shared components can result in new effects. Our global approach illuminates different aspects of the structure and functioning of modules, revealing the importance of dynamical characteristics as well as biochemical features; this provides a methodological platform for investigating the complexity of natural modules shaped by evolution, elucidating the effects of ambient networks on a module in multiple cellular contexts, and highlighting the capabilities and constraints for engineering robust synthetic modules. Overall, such a systems framework provides a platform for bridging the gap between non-linear information processing modules, in isolation and as parts of networks, and a basis for understanding new aspects of natural and engineered cellular networks.

A Review of the Interactions between Alcohol and the Endocannabinoid System: Implications for Alcohol Dependence and Future Directions for Research

PubMed Central

Pava, Matthew J.; Woodward, John J.

2012-01-01

Over the past fifty years a significant body of evidence has been compiled suggesting an interaction between the endocannabinoid (EC) system and alcohol dependence. However, much of this work has been conducted only in the past two decades following the elucidation of the molecular constituents of the EC system that began with the serendipitous discovery of the cannabinoid 1 receptor (CB1). Since then, novel pharmacological and genetic tools have enabled researchers to manipulate select components of the EC system, to determine their contribution to the motivation to consume ethanol. From these preclinical studies, it is evident that CB1 contributes the motivational and reinforcing properties of ethanol, and chronic consumption of ethanol alters EC transmitter levels and CB1 expression in brain nuclei associated with addiction pathways. These results are augmented by in vitro and ex vivo studies showing that acute and chronic treatment with ethanol produces physiologically relevant alterations in the function of the EC system. This report provides a current and comprehensive review of the literature regarding the interactions between ethanol and the EC system. We begin be reviewing the studies published prior to the discovery of the EC system that compared the behavioral and physiological effects of cannabinoids with ethanol in addition to cross-tolerance between these drugs. Next, a brief overview of the molecular constituents of the EC system is provided as context for the subsequent review of more recent studies examining the interaction of ethanol with the EC system. These results are compiled into a summary providing a scheme for the known changes to the components of the EC system in different stages of alcohol dependence. Finally, future directions for research are discussed. PMID:22459871

Materials interactions between the thermoelectric converter and the 5kwe reactor system

NASA Technical Reports Server (NTRS)

Ferry, P. B.

1973-01-01

The integration of a compact thermoelectric converter with a 5-kwe reactor system is described. Material interaction uncertainties study is also presented. This includes degradation of the required austenitic - refractory metal transition joint during operation at high temperatures; loss of corrosion resistance; embrittlement by the presence of hydrogen; and loss of design margin by transport of interstitial elements. Analysis and limited experimental evidence indicate that these potential materials interactions can be adequately controlled. Group 5-2 refractory metals can be utilized without unacceptable adverse effect on system reliability.

A system dynamics model of human-water interaction in anthropogenic droughts

NASA Astrophysics Data System (ADS)

Blair, Peter; Buytaert, Wouter

2016-04-01

Modelling is set to be a key part of socio-hydrology's quest to understand the dynamics and long-term consequences of human-water interactions. As a subject in its infancy, still learning the questions to ask, conceptual models are of particular use in trying to understand the general nature of human-water systems. The conceptual model of Di Baldassarre et al. (2013), which investigates human-flood interactions, has been widely discussed, prompting great steps forward in understanding and coverage of socio-hydrology. The development of further conceptual models could generate further discussion and understanding. Flooding is one archetypal example of a system of human-water interaction; another is the case of water stress and drought. There has been a call to recognise and understand anthropogenic drought (Aghakouchak et al. 2015), and so this study investigates the nature of the socio-hydrological dynamics involved in these situations. Here we present a system dynamics model to simulate human-water interactions in the context of water-stressed areas, where drought is induced via a combination of lower than usual water availability and relatively high water use. It is designed based on an analysis of several case-studies where recent droughts have occurred, or where the prospect of drought looms. The locations investigated are Spain, Southeast Brazil, Northeast China and California. The numerical system dynamics model is based on causal loop, and stocks and flows diagrams, which are in turn developed from the qualitative analysis of the different cases studied. The study uses a comparative approach, which has the advantage of eliciting general system characteristics from the similarities between cases, while using the differences to determine the important factors which lead to different system behaviours. References: Aghakouchak, A., Feldman, D., Hoerling, M., Huxman, T., Lund, J., 2015. Recognize anthropogenic drought. Nature, 524, pp.409-411. Di Baldassarre, G., Viglione, A., Carr, G., Kuil, L., Salinas, J. L., Blöschl, G., 2013. Socio-hydrology: conceptualising human-flood interactions. Hydrology and Earth System Sciences, 17(8), pp.3295-3303. Available at: http://www.hydrol-earth-syst-sci.net/17/3295/2013/ [Accessed August 8, 2014].

Interactions between Patients, Providers, and Health Systems and Technical Quality of Care

PubMed Central

Yelin, Edward; Yazdany, Jinoos; Tonner, Chris; Trupin, Laura; Criswell, Lindsey A.; Katz, Patricia; Schmajuk, Gabriela

2014-01-01

Objectives Prior studies have established disparities by race/ethnicity and socioeconomic status (SES) in the kind, quantity, and technical quality of SLE care and outcomes. In this study we evaluate whether disparities exist in assessments of interactions with health care providers and health plans and whether such interactions affect the technical quality of SLE care. Methods Data derive from the Lupus Outcomes Study (LOS). Principal data collection is an annual structured phone interview including items from the Consumer Assessment of Health Plans and Interpersonal Processes of Care Scale measuring dimensions of health care interactions. We use general estimating equations to assess whether disparities exist by race/ethnicity and SES in being in the lowest quartile of ratings of such interactions and whether ratings in the lowest quartile of interactions are associated with technical quality of care after adjustment for sociodemographic and disease characteristics. Results In the 2012 LOS interview, there were 793 respondents, of whom 640 had ≥1 visits to their principal SLE provider. Non-white race/ethnicity and education were not associated with low ratings on any dimension of provider or system interaction; poverty was associated only with low ratings of health plan interactions. After adjustment for demographics, SLE status, and health care variables, ratings in the lowest quartile on all dimensions were associated with significantly lower technical quality of care. Conclusions Ratings in the lowest quartile on all dimensions of interactions with providers and the health care system were associated with lower technical quality of care, potentially resulting in poorer SLE outcomes. PMID:25132660

Construction of Interaction Layer on Socio-Environmental Simulation

NASA Astrophysics Data System (ADS)

Torii, Daisuke; Ishida, Toru

In this study, we propose a method to construct a system based on a legacy socio-environmental simulator which enables to design more realistic interaction models in socio-environmetal simulations. First, to provide a computational model suitable for agent interactions, an interaction layer is constructed and connected from outside of a legacy socio-environmental simulator. Next, to configure the agents interacting ability, connection description for controlling the flow of information in the connection area is provided. As a concrete example, we realized an interaction layer by Q which is a scenario description language and connected it to CORMAS, a socio-envirionmental simulator. Finally, we discuss the capability of our method, using the system, in the Fire-Fighter domain.

Carboxyl-terminated PAMAM dendrimer interaction with 1-palmitoyl-2-oleoyl phosphocholine bilayers

USDA-ARS?s Scientific Manuscript database

Polycationic polymers and liposomes have a great potential use as individual drug delivery systems and greater potential as a combined drug delivery system. Thus, it is important to better understand the interactions of polymers with phospholipid bilayers. A mechanistic study of carboxyl-terminate...

Multi-agent-based bio-network for systems biology: protein-protein interaction network as an example.

PubMed

Ren, Li-Hong; Ding, Yong-Sheng; Shen, Yi-Zhen; Zhang, Xiang-Feng

2008-10-01

Recently, a collective effort from multiple research areas has been made to understand biological systems at the system level. This research requires the ability to simulate particular biological systems as cells, organs, organisms, and communities. In this paper, a novel bio-network simulation platform is proposed for system biology studies by combining agent approaches. We consider a biological system as a set of active computational components interacting with each other and with an external environment. Then, we propose a bio-network platform for simulating the behaviors of biological systems and modelling them in terms of bio-entities and society-entities. As a demonstration, we discuss how a protein-protein interaction (PPI) network can be seen as a society of autonomous interactive components. From interactions among small PPI networks, a large PPI network can emerge that has a remarkable ability to accomplish a complex function or task. We also simulate the evolution of the PPI networks by using the bio-operators of the bio-entities. Based on the proposed approach, various simulators with different functions can be embedded in the simulation platform, and further research can be done from design to development, including complexity validation of the biological system.

Contact interaction between a layered foundation and a system of annular punches with complex base shapes

NASA Astrophysics Data System (ADS)

Kazakov, K. E.; Kurdina, S. P.

2018-04-01

We study the contact interaction between a system of rigid annular punches and a viscoelastic two-layer foundation. The upper layer is thin compared with the punch width. We study the case where the punch shapes are described by a rapidly varying functions. We use special methods for constructing the solutions, because the standard methods are inefficient.

Progress towards measurement of entanglement entropy dynamics in one-dimensional interacting systems in the presence of disorder

NASA Astrophysics Data System (ADS)

Lukin, Alexander; Tai, M. Eric; Rispoli, Matthew; Schittko, Robert; Menke, Tim; Kaufman, Adam; Greiner, Markus

2017-04-01

Many-body localized states appear at odds with thermalization as they preserve the memory of their initial state. This behavior has drawn significant theoretical and experimental attention in recent years. Real space localization has been observed on various platforms and under a number of experimental conditions, both with and without interactions. However, the characteristic logarithmic growth of entanglement entropy, which distinguishes the many-body localized state from the non-interacting Anderson localized state, has only been studied in numerics and has yet to be investigated experimentally. We are working towards the phenomenon of localization in one dimensional, interacting Bose-Hubbard system using a quantum gas microscope. With site-resolved addressing and readout, our microscope provides full control over the studied system, in particular it allows us to add disorder into our system using a Fourier plane hologram. This gives us access to both local observables, such as the occupation of individual lattice sites, as well as the entanglement entropy. I will present our progress towards measuring the dependence of the entanglement entropy grows on the disorder strength and interactions in our system. National Science Foundation, Gordon and Betty Moore Foundation's EPiQS Initiative, Air Force Office of Scientific Research MURI program, NSF Graduate Research Fellowship Program (MNR).

Interactions between spatially explicit conservation and management measures: implications for the governance of marine protected areas.

PubMed

Cárcamo, P Francisco; Gaymer, Carlos F

2013-12-01

Marine protected areas are not established in an institutional and governance vacuum and managers should pay attention to the wider social-ecological system in which they are immersed. This article examines Islas Choros-Damas Marine Reserve, a small marine protected area located in a highly productive and biologically diverse coastal marine ecosystem in northern Chile, and the interactions between human, institutional, and ecological dimensions beyond those existing within its boundaries. Through documents analysis, surveys, and interviews, we described marine reserve implementation (governing system) and the social and natural ecosystem-to-be-governed. We analyzed the interactions and the connections between the marine reserve and other spatially explicit conservation and/or management measures existing in the area and influencing management outcomes and governance. A top-down approach with poor stakeholder involvement characterized the implementation process. The marine reserve is highly connected with other spatially explicit measures and with a wider social-ecological system through various ecological processes and socio-economic interactions. Current institutional interactions with positive effects on the management and governance are scarce, although several potential interactions may be developed. For the study area, any management action must recognize interferences from outside conditions and consider some of them (e.g., ecotourism management) as cross-cutting actions for the entire social-ecological system. We consider that institutional interactions and the development of social networks are opportunities to any collective effort aiming to improve governance of Islas Choros-Damas marine reserve. Communication of connections and interactions between marine protected areas and the wider social-ecological system (as described in this study) is proposed as a strategy to improve stakeholder participation in Chilean marine protected areas.

Interactions Between Spatially Explicit Conservation and Management Measures: Implications for the Governance of Marine Protected Areas

NASA Astrophysics Data System (ADS)

Cárcamo, P. Francisco; Gaymer, Carlos F.

2013-12-01

Marine protected areas are not established in an institutional and governance vacuum and managers should pay attention to the wider social-ecological system in which they are immersed. This article examines Islas Choros-Damas Marine Reserve, a small marine protected area located in a highly productive and biologically diverse coastal marine ecosystem in northern Chile, and the interactions between human, institutional, and ecological dimensions beyond those existing within its boundaries. Through documents analysis, surveys, and interviews, we described marine reserve implementation (governing system) and the social and natural ecosystem-to-be-governed. We analyzed the interactions and the connections between the marine reserve and other spatially explicit conservation and/or management measures existing in the area and influencing management outcomes and governance. A top-down approach with poor stakeholder involvement characterized the implementation process. The marine reserve is highly connected with other spatially explicit measures and with a wider social-ecological system through various ecological processes and socio-economic interactions. Current institutional interactions with positive effects on the management and governance are scarce, although several potential interactions may be developed. For the study area, any management action must recognize interferences from outside conditions and consider some of them (e.g., ecotourism management) as cross-cutting actions for the entire social-ecological system. We consider that institutional interactions and the development of social networks are opportunities to any collective effort aiming to improve governance of Islas Choros-Damas marine reserve. Communication of connections and interactions between marine protected areas and the wider social-ecological system (as described in this study) is proposed as a strategy to improve stakeholder participation in Chilean marine protected areas.

Rashba and Dresselhaus spin-orbit interactions effects on electronic features of a two dimensional elliptic quantum dot

NASA Astrophysics Data System (ADS)

Mokhtari, P.; Rezaei, G.; Zamani, A.

2017-06-01

In this paper, electronic structure of a two dimensional elliptic quantum dot under the influence of external electric and magnetic fields are studied in the presence of Rashba and Dresselhaus spin-orbit interactions. This investigation is done computationally and to do this, at first, the effective Hamiltonian of the system by considering the spin-orbit coupling is demonstrated in the presence of applied electric and magnetic fields and afterwards the Schrödinger equation is solved using the finite difference approach. Utilizing finite element method, eigenvalues and eigenstates of the system are calculated and the effect of the external fields, the size of the dot as well as the strength of Rashba spin-orbit interaction are studied. Our results indicate that, Spin-orbit interactions, external fields and the dot size have a great influence on the electronic structure of the system.

Quantum chaos and breaking of all anti-unitary symmetries in Rydberg excitons.

PubMed

Aßmann, Marc; Thewes, Johannes; Fröhlich, Dietmar; Bayer, Manfred

2016-07-01

Symmetries are the underlying principles of fundamental interactions in nature. Chaos in a quantum system may emerge from breaking these symmetries. Compared to vacuum, crystals are attractive for studying quantum chaos, as they not only break spatial isotropy, but also lead to novel quasiparticles with modified interactions. Here we study yellow Rydberg excitons in cuprous oxide which couple strongly to the vacuum light field and interact significantly with crystal phonons, leading to inversion symmetry breaking. In a magnetic field, time-reversal symmetry is also broken and the exciton states show a complex splitting pattern, resulting in quadratic level repulsion for small splittings. In contrast to atomic chaotic systems in a magnetic field, which show only a linear level repulsion, this is a signature of a system where all anti-unitary symmetries are broken simultaneously. This behaviour can otherwise be found only for the electro-weak interaction or engineered billiards.

Control Of Flexible Structures-2 (COFS-2) flight control, structure and gimbal system interaction study

NASA Technical Reports Server (NTRS)

Fay, Stanley; Gates, Stephen; Henderson, Timothy; Sackett, Lester; Kirchwey, Kim; Stoddard, Isaac; Storch, Joel

1988-01-01

The second Control Of Flexible Structures Flight Experiment (COFS-2) includes a long mast as in the first flight experiment, but with the Langley 15-m hoop column antenna attached via a gimbal system to the top of the mast. The mast is to be mounted in the Space Shuttle cargo bay. The servo-driven gimbal system could be used to point the antenna relative to the mast. The dynamic interaction of the Shuttle Orbiter/COFS-2 system with the Orbiter on-orbit Flight Control System (FCS) and the gimbal pointing control system has been studied using analysis and simulation. The Orbiter pointing requirements have been assessed for their impact on allowable free drift time for COFS experiments. Three fixed antenna configurations were investigated. Also simulated was Orbiter attitude control behavior with active vernier jets during antenna slewing. The effect of experiment mast dampers was included. Control system stability and performance and loads on various portions of the COFS-2 structure were investigated. The study indicates possible undesirable interaction between the Orbiter FCS and the flexible, articulated COFS-2 mast/antenna system, even when restricted to vernier reaction jets.

A computational study on the strength and nature of bifurcated aerogen bonds

NASA Astrophysics Data System (ADS)

Esrafili, Mehdi D.; Sadr-Mousavi, Asma

2018-04-01

A quantum chemical study is performed to unveil the strength and bonding properties of bifurcated aerogen-bonding (BAB) interactions in complexes formed between ZO3 molecules (Z = Ar, Kr and Xe) and 1,2-dihydroxybenzene derivatives. The interaction energies of the resulting complexes are between -7.70 and -15.59 kcal/mol. The nature of BAB interactions is identified by the molecular electrostatic potential, quantum theory of atoms in molecules, noncovalent interaction index and natural bond orbital analyses. The mutual influence between the BAB and a halogen, chalcogen, pnicogen or tetrel bonding interaction is also studied in systems where these interactions coexist.

Nonlinear Dynamics on Interconnected Networks

NASA Astrophysics Data System (ADS)

Arenas, Alex; De Domenico, Manlio

2016-06-01

Networks of dynamical interacting units can represent many complex systems, from the human brain to transportation systems and societies. The study of these complex networks, when accounting for different types of interactions has become a subject of interest in the last few years, especially because its representational power in the description of users' interactions in diverse online social platforms (Facebook, Twitter, Instagram, etc.) [1], or in representing different transportation modes in urban networks [2,3]. The general name coined for these networks is multilayer networks, where each layer accounts for a type of interaction (see Fig. 1).

[Noncovalent cation-π interactions--their role in nature].

PubMed

Fink, Krzysztof; Boratyński, Janusz

2014-11-07

Non-covalent interactions play an extremely important role in organisms. The main non-covalent interactions in nature are: ion-ion interactions, dipole-dipole interactions, hydrogen bonds, and van der Waals interactions. A new kind of intermolecular interactions--cation-π interactions--is gaining increasing attention. These interactions occur between a cation and a π system. The main contributors to cation-π interactions are electrostatic, polarization and, to a lesser extent, dispersion interactions. At first, cation-π interactions were studied in a gas phase, with metal cation-aromatic system complexes. The characteristics of these complexes are as follows: an increase of cation atomic number leads to a decrease of interaction energy, and an increase of cation charge leads to an increase of interaction energy. Aromatic amino acids bind with metal cations mainly through interactions with their main chain. Nevertheless, cation-π interaction with a hydrophobic side chain significantly enhances binding energy. In water solutions most cations preferentially interact with water molecules rather than aromatic systems. Cation-π interactions occur in environments with lower accessibility to a polar solvent. Cation-π interactions can have a stabilizing role on the secondary, tertiary and quaternary structure of proteins. These interactions play an important role in substrate or ligand binding sites in many proteins, which should be taken into consideration when the screening of effective inhibitors for these proteins is carried out. Cation-π interactions are abundant and play an important role in many biological processes.

Unintended consequences of information technologies in health care--an interactive sociotechnical analysis.

PubMed

Harrison, Michael I; Koppel, Ross; Bar-Lev, Shirly

2007-01-01

Many unintended and undesired consequences of Healthcare Information Technologies (HIT) flow from interactions between the HIT and the healthcare organization's sociotechnical system-its workflows, culture, social interactions, and technologies. This paper develops and illustrates a conceptual model of these processes that we call Interactive Sociotechnical Analysis (ISTA). ISTA captures common types of interaction with special emphasis on recursive processes, i.e., feedback loops that alter the newly introduced HIT and promote second-level changes in the social system. ISTA draws on prior studies of unintended consequences, along with research in sociotechnical systems, ergonomics, social informatics, technology-in-practice, and social construction of technology. We present five types of sociotechnical interaction and illustrate each with cases from published research. The ISTA model should further research on emergent and recursive processes in HIT implementation and their unintended consequences. Familiarity with the model can also foster practitioners' awareness of unanticipated consequences that only become evident during HIT implementation.

Various topological Mott insulators and topological bulk charge pumping in strongly-interacting boson system in one-dimensional superlattice

NASA Astrophysics Data System (ADS)

Kuno, Yoshihito; Shimizu, Keita; Ichinose, Ikuo

2017-12-01

In this paper, we study a one-dimensional boson system in a superlattice potential. This system is experimentally feasible by using ultracold atomic gases, and attracts much attention these days. It is expected that the system has a topological phase called a topological Mott insulator (TMI). We show that in strongly-interacting cases, the competition between the superlattice potential and the on-site interaction leads to various TMIs with a non-vanishing integer Chern number. Compared to the hard-core case, the soft-core boson system exhibits rich phase diagrams including various non-trivial TMIs. By using the exact diagonalization, we obtain detailed bulk-global phase diagrams including the TMIs with high Chern numbers and also various non-topological phases. We also show that in adiabatic experimental setups, the strongly-interacting bosonic TMIs exhibit the topological particle transfer, i.e., the topological charge pumping phenomenon, similarly to weakly-interacting systems. The various TMIs are characterized by topological charge pumping as it is closely related to the Chern number, and therefore the Chern number is to be observed in feasible experiments.

Kraus Operators for a Pair of Interacting Qubits: a Case Study

NASA Astrophysics Data System (ADS)

Arsenijević, M.; Jeknić-Dugić, J.; Dugić, M.

2018-04-01

The Kraus form of the completely positive dynamical maps is appealing from the mathematical and the point of the diverse applications of the open quantum systems theory. Unfortunately, the Kraus operators are poorly known for the two-qubit processes. In this paper, we derive the Kraus operators for a pair of interacting qubits, while the strength of the interaction is arbitrary. One of the qubits is subjected to the x-projection spin measurement. The obtained results are applied to calculate the dynamics of the entanglement in the qubits system. We obtain the loss of the correlations in the finite time interval; the stronger the inter-qubit interaction, the longer lasting entanglement in the system.

Kraus Operators for a Pair of Interacting Qubits: a Case Study

NASA Astrophysics Data System (ADS)

Arsenijević, M.; Jeknić-Dugić, J.; Dugić, M.

2018-06-01

The Kraus form of the completely positive dynamical maps is appealing from the mathematical and the point of the diverse applications of the open quantum systems theory. Unfortunately, the Kraus operators are poorly known for the two-qubit processes. In this paper, we derive the Kraus operators for a pair of interacting qubits, while the strength of the interaction is arbitrary. One of the qubits is subjected to the x-projection spin measurement. The obtained results are applied to calculate the dynamics of the entanglement in the qubits system. We obtain the loss of the correlations in the finite time interval; the stronger the inter-qubit interaction, the longer lasting entanglement in the system.

Investigation of the Interaction between Nafion Ionomer and Surface Functionalized Carbon Black Using Both Ultrasmall Angle X-ray Scattering and Cryo-TEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Fan; Xin, Le; Uzunoglu, Aytekin

In making a catalyst ink, the interaction between Nafion ionomer and catalyst support are the key factors that directly affect both ionic conductivity and electronic conductivity of the catalyst layer in a membrane electrode assembly (MEA). One of the major aims of this investigation is to understand the behavior of the catalyst support, Vulcan XC-72 (XC-72) aggregates, in the existence of the Nafion ionomer in a catalyst ink to fill the knowledge gap of the interaction of these components. The dispersion of catalyst ink not only depends on the solvent, but also depends on the interaction of Nafion and carbonmore » particles in the ink. The interaction of Nafion ionomer particles and XC-72 catalyst aggregates in liquid media was studied using ultra small angle x-ray scattering (USAXS) and cryogenic TEM techniques. Carbon black XC-72) and functionalized carbon black systems were introduced to study the interaction behaviors. A multiple curve fitting was used to extract the particle size and size distribution from scattering data. The results suggest that the particle size and size distribution of each system changed significantly in Nafion + XC-72 system, Nafion + NH2-XC72 system, and Nafion + SO3H-XC-72 system, which indicates that an interaction among these components (i.e. ionomer particles and XC-72 aggregates) exists. The cryogenic TEM, which allows for the observation the size of particles in a liquid, was used to validate the scattering results and shows excellent agreement.« less

What is health systems responsiveness? Review of existing knowledge and proposed conceptual framework.

PubMed

Mirzoev, Tolib; Kane, Sumit

2017-01-01

Responsiveness is a key objective of national health systems. Responsive health systems anticipate and adapt to existing and future health needs, thus contributing to better health outcomes. Of all the health systems objectives, responsiveness is the least studied, which perhaps reflects lack of comprehensive frameworks that go beyond the normative characteristics of responsive services. This paper contributes to a growing, yet limited, knowledge on this topic. Herewith, we review the current frameworks for understanding health systems responsiveness and drawing on these, as well as key frameworks from the wider public services literature, propose a comprehensive conceptual framework for health systems responsiveness. This paper should be of interest to different stakeholders who are engaged in analysing and improving health systems responsiveness. Our review shows that existing knowledge on health systems responsiveness can be extended along the three areas. First, responsiveness entails an actual experience of people's interaction with their health system, which confirms or disconfirms their initial expectations of the system. Second, the experience of interaction is shaped by both the people and the health systems sides of this interaction. Third, different influences shape people's interaction with their health system, ultimately affecting their resultant experiences. Therefore, recognition of both people and health systems sides of interaction and their key determinants would enhance the conceptualisations of responsiveness. Our proposed framework builds on, and advances, the core frameworks in the health systems literature. It positions the experience of interaction between people and health system as the centrepiece and recognises the determinants of responsiveness experience both from the health systems (eg, actors, processes) and the people (eg, initial expectations) sides. While we hope to trigger further thinking on the conceptualisation of health system responsiveness, the proposed framework can guide assessments of, and interventions to strengthen, health systems responsiveness.

What is health systems responsiveness? Review of existing knowledge and proposed conceptual framework

PubMed Central

Mirzoev, Tolib; Kane, Sumit

2017-01-01

Responsiveness is a key objective of national health systems. Responsive health systems anticipate and adapt to existing and future health needs, thus contributing to better health outcomes. Of all the health systems objectives, responsiveness is the least studied, which perhaps reflects lack of comprehensive frameworks that go beyond the normative characteristics of responsive services. This paper contributes to a growing, yet limited, knowledge on this topic. Herewith, we review the current frameworks for understanding health systems responsiveness and drawing on these, as well as key frameworks from the wider public services literature, propose a comprehensive conceptual framework for health systems responsiveness. This paper should be of interest to different stakeholders who are engaged in analysing and improving health systems responsiveness. Our review shows that existing knowledge on health systems responsiveness can be extended along the three areas. First, responsiveness entails an actual experience of people’s interaction with their health system, which confirms or disconfirms their initial expectations of the system. Second, the experience of interaction is shaped by both the people and the health systems sides of this interaction. Third, different influences shape people’s interaction with their health system, ultimately affecting their resultant experiences. Therefore, recognition of both people and health systems sides of interaction and their key determinants would enhance the conceptualisations of responsiveness. Our proposed framework builds on, and advances, the core frameworks in the health systems literature. It positions the experience of interaction between people and health system as the centrepiece and recognises the determinants of responsiveness experience both from the health systems (eg, actors, processes) and the people (eg, initial expectations) sides. While we hope to trigger further thinking on the conceptualisation of health system responsiveness, the proposed framework can guide assessments of, and interventions to strengthen, health systems responsiveness. PMID:29225953

Macrolide drug interactions: an update.

PubMed

Pai, M P; Graci, D M; Amsden, G W

2000-04-01

To describe the current drug interaction profiles for the commonly used macrolides in the US and Europe, and to comment on the clinical impact of these interactions. A MEDLINE search (1975-1998) was performed to identify all pertinent studies, review articles, and case reports. When appropriate information was not available in the literature, data were obtained from the product manufacturers. All available data were reviewed to provide an unbiased account of possible drug interactions. Data for some of the interactions were not available from the literature, but were available from abstracts or company-supplied materials. Although the data were not always explicit, the best attempt was made to deliver pertinent information that clinical practitioners would need to formulate practice opinions. When more in-depth information was supplied in the form of a review or study report, a thorough explanation of pertinent methodology was supplied. Several clinically significant drug interactions have been identified since the approval of erythromycin. These interactions usually were related to the inhibition of the cytochrome P450 enzyme systems, which are responsible for the metabolism of many drugs. The decreased metabolism by the macrolides has in some instances resulted in potentially severe adverse events. The development and marketing of newer macrolides are hoped to improve the drug interaction profile associated with this class. However, this has produced variable success. Some of the newer macrolides demonstrated an interaction profile similar to that of erythromycin; others have improved profiles. The most success in avoiding drug interactions related to the inhibition of cytochrome P450 has been through the development of the azalide subclass, of which azithromycin is the first and only to be marketed. Azithromycin has not been demonstrated to inhibit the cytochrome P450 system in studies using a human liver microsome model, and to date has produced none of the classic drug interactions characteristic of the macrolides. Most of the available data regarding macrolide drug interactions are from studies in healthy volunteers and case reports. These data suggest that clarithromycin appears to have an interaction profile similar to that of erythromycin. Given this similarity, it is important to consider the interaction profile of clarithromycin when using erythromycin. This is especially necessary as funds for further studies of a medication available in generic form (e.g., erythromycin) are limited. Azithromycin has produced few clinically significant interactions with any agent cleared through the cytochrome P450 enzyme system. Although the available data are promising, the final test should come from studies conducted in patients who are taking potentially interacting compounds on a chronic basis.

Trophic interaction modifications: an empirical and theoretical framework.

PubMed

Terry, J Christopher D; Morris, Rebecca J; Bonsall, Michael B

2017-10-01

Consumer-resource interactions are often influenced by other species in the community. At present these 'trophic interaction modifications' are rarely included in ecological models despite demonstrations that they can drive system dynamics. Here, we advocate and extend an approach that has the potential to unite and represent this key group of non-trophic interactions by emphasising the change to trophic interactions induced by modifying species. We highlight the opportunities this approach brings in comparison to frameworks that coerce trophic interaction modifications into pairwise relationships. To establish common frames of reference and explore the value of the approach, we set out a range of metrics for the 'strength' of an interaction modification which incorporate increasing levels of contextual information about the system. Through demonstrations in three-species model systems, we establish that these metrics capture complimentary aspects of interaction modifications. We show how the approach can be used in a range of empirical contexts; we identify as specific gaps in current understanding experiments with multiple levels of modifier species and the distributions of modifications in networks. The trophic interaction modification approach we propose can motivate and unite empirical and theoretical studies of system dynamics, providing a route to confront ecological complexity. © 2017 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

Preliminary control/structure interaction study of coupled Space Station Freedom/Assembly Work Platform/orbiter

NASA Technical Reports Server (NTRS)

Singh, Sudeep K.; Lindenmoyer, Alan J.

1989-01-01

Results are presented from a preliminary control/structure interaction study of the Space Station, the Assembly Work Platform, and the STS orbiter dynamics coupled with the orbiter and station control systems. The first three Space Station assembly flight configurations and their finite element representations are illustrated. These configurations are compared in terms of control authority in each axis and propellant usage. The control systems design parameters during assembly are computed. Although the rigid body response was acceptable with the orbiter Primary Reaction Control System, the flexible body response showed large structural deflections and loads. It was found that severe control/structure interaction occurred if the stiffness of the Assembly Work Platform was equal to that of the station truss. Also, the response of the orbiter Vernier Reaction Control System to small changes in inertia properties is examined.

Incommensurability and phase transitions in two-dimensional X Y models with Dzyaloshinskii-Moriya interactions

NASA Astrophysics Data System (ADS)

Liu, Huiping; Plascak, J. A.; Landau, D. P.

2018-05-01

The Dzyaloshinskii-Moriya (DM) interaction in magnetic models is the result of a combination of superexchange and spin-orbital coupling, and it can give rise to rich phase-transition behavior. In this paper, we study ferromagnetic X Y models with the DM interaction on two-dimensional L ×L square lattices using a hybrid Monte Carlo algorithm. To match the incommensurability between the resultant spin structure and the lattice due to the DM interaction, a fluctuating boundary condition is adopted. We also define a different kind of order parameter and use finite-size scaling to study the critical properties of this system. We find that a Kosterlitz-Thouless-like phase transition appears in this system and that the phase-transition temperature shifts toward higher temperature with increasing DM interaction strength.

The light-harvesting antenna of Chlorobium tepidum: interactions between the FMO protein and the major chlorosome protein CsmA studied by surface plasmon resonance.

PubMed

Pedersen, Marie Østergaard; Borch, Jonas; Højrup, Peter; Cox, Raymond P; Miller, Mette

2006-09-01

Green sulfur bacteria possess two external light-harvesting antenna systems, the chlorosome and the FMO protein, which participate in a sequential energy transfer to the reaction centers embedded in the cytoplasmic membrane. However, little is known about the physical interaction between these two antenna systems. We have studied the interaction between the major chlorosome protein, CsmA, and the FMO protein in Chlorobium tepidum using surface plasmon resonance (SPR). Our results show an interaction between the FMO protein and an immobilized synthetic peptide corresponding to 17 amino acids at the C terminal of CsmA. This interaction is dependent on the presence of a motif comprising six amino acids that are highly conserved in all the currently available CsmA protein sequences.

The Development and Evaluation of a Computer-Based System for Managing the Design and Pilot-Testing of Interactive Videodisc Programs. Training and Development Research Center, Project Number Forty-Three.

ERIC Educational Resources Information Center

Sayre, Scott Alan

The purpose of this study was to develop and validate a computer-based system that would allow interactive video developers to integrate and manage the design components prior to production. These components of an interactive video (IVD) program include visual information in a variety of formats, audio information, and instructional techniques,…

Assessment of geometry in 2D immune systems using high accuracy laser-based bioprinting techniques (Conference Presentation)

NASA Astrophysics Data System (ADS)

Lauzurica, Sara; Márquez, Andrés.; Molpeceres, Carlos; Notario, Laura; Gómez-Fontela, Miguel; Lauzurica, Pilar

2017-02-01

The immune system is a very complex system that comprises a network of genetic and signaling pathways subtending a network of interacting cells. The location of the cells in a network, along with the gene products they interact with, rules the behavior of the immune system. Therefore, there is a great interest in understanding properly the role of a cell in such networks to increase our knowledge of the immune system response. In order to acquire a better understanding of these processes, cell printing with high spatial resolution emerges as one of the promising approaches to organize cells in two and three-dimensional patterns to enable the study the geometry influence in these interactions. In particular, laser assisted bio-printing techniques using sub-nanosecond laser sources have better characteristics for application in this field, mainly due to its higher spatial resolution, cell viability percentage and process automation. This work presents laser assisted bio-printing of antigen-presenting cells (APCs) in two-dimensional geometries, placing cellular components on a matrix previously generated on demand, permitting to test the molecular interactions between APCs and lymphocytes; as well as the generation of two-dimensional structures designed ad hoc in order to study the mechanisms of mobilization of immune system cells. The use of laser assisted bio-printing, along with APCs and lymphocytes emulate the structure of different niches of the immune system so that we can analyse functional requirement of these interaction.

An Investigation of Game-Embedded Handheld Devices to Enhance English Learning

ERIC Educational Resources Information Center

Hung, Hui-Chun; Young, Shelley Shwu-Ching

2015-01-01

This study proposed and implemented a system combining the advantages of both educational games and wireless handheld technology to promote the interactive English learning in the classroom setting. An interactive English vocabulary acquisition board game was designed with the system being implemented on handheld devices. Thirty sixth-grade…

The Development of Teaching and Learning in Bright-Field Microscopy Technique

ERIC Educational Resources Information Center

Iskandar, Yulita Hanum P.; Mahmud, Nurul Ethika; Wahab, Wan Nor Amilah Wan Abdul; Jamil, Noor Izani Noor; Basir, Nurlida

2013-01-01

E-learning should be pedagogically-driven rather than technologically-driven. The objectives of this study are to develop an interactive learning system in bright-field microscopy technique in order to support students' achievement of their intended learning outcomes. An interactive learning system on bright-field microscopy technique was…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rebolini, Elisa, E-mail: rebolini@lct.jussieu.fr; Toulouse, Julien, E-mail: julien.toulouse@upmc.fr; Savin, Andreas, E-mail: savin@lct.jussieu.fr

We present a study of the variation of total energies and excitation energies along a range-separated adiabatic connection. This connection links the non-interacting Kohn–Sham electronic system to the physical interacting system by progressively switching on the electron–electron interactions whilst simultaneously adjusting a one-electron effective potential so as to keep the ground-state density constant. The interactions are introduced in a range-dependent manner, first introducing predominantly long-range, and then all-range, interactions as the physical system is approached, as opposed to the conventional adiabatic connection where the interactions are introduced by globally scaling the standard Coulomb interaction. Reference data are reported for themore » He and Be atoms and the H{sub 2} molecule, obtained by calculating the short-range effective potential at the full configuration-interaction level using Lieb's Legendre-transform approach. As the strength of the electron–electron interactions increases, the excitation energies, calculated for the partially interacting systems along the adiabatic connection, offer increasingly accurate approximations to the exact excitation energies. Importantly, the excitation energies calculated at an intermediate point of the adiabatic connection are much better approximations to the exact excitation energies than are the corresponding Kohn–Sham excitation energies. This is particularly evident in situations involving strong static correlation effects and states with multiple excitation character, such as the dissociating H{sub 2} molecule. These results highlight the utility of long-range interacting reference systems as a starting point for the calculation of excitation energies and are of interest for developing and analyzing practical approximate range-separated density-functional methodologies.« less

Difference of carboxybetaine and oligo(ethylene glycol) moieties in altering hydrophobic interactions: a molecular simulation study.

PubMed

Shao, Qing; White, Andrew D; Jiang, Shaoyi

2014-01-09

Polycarboxybetaine and poly(ethylene glycol) materials resist nonspecific protein adsorption but differ in influencing biological functions such as enzymatic activity. To investigate this difference, we studied the influence of carboxybetaine and oligo(ethylene glycol) moieties on hydrophobic interactions using molecular simulations. We employed a model system composed of two non-polar plates and studied the potential of mean force of plate-plate association in carboxybetaine, (ethylene glycol)4, and (ethylene glycol)2 solutions using well-tempered metadynamics simulations. Water, trimethylamine N-oxide, and urea solutions were used as reference systems. We analyzed the variation of the potential of mean force in various solutions to study how carboxybetaine and oligo(ethylene glycol) moieties influence the hydrophobic interactions. To study the origin of their influence, we analyzed the normalized distributions of moieties and water molecules using molecular dynamics simulations. The simulation results showed that oligo(ethylene glycol) moieties repel water molecules away from the non-polar plates and weaken the hydrophobic interactions. Carboxybetaine moieties do not repel water molecules away from the plates and therefore do not influence the hydrophobic interactions.

The Socialization of Virtual Teams: Implications for ISD

NASA Astrophysics Data System (ADS)

Mullally, Brenda; Stapleton, Larry

Studies show that Information Systems Development (ISD) projects do not fulfil stakeholder expectations of completion time, quality and budget. (2005) study shows that development is more about social interaction and mutual understanding than following a prescribed method. Systems development is a social process where interactions help to make sense of the reality within which the system is developed (Hirschheirn et al., 1991). Research concentrates on methodology when in fact method may not be the primary problem. Authors have called for further research to investigate the true nature of the current systems development environment in real organisational situations (Fitzgerald, 2000).

Ideology and gender: observers' system justification and targets' gender as interactive predictors of citizenship expectations.

PubMed

Chiaburu, Dan S; Harris, T Brad; Smith, Troy A

2014-01-01

We integrate system justification and social role theory to explain how observers' system justification and target employees' gender interact to predict observers' expectations of targets' sportsmanship citizenship behaviors. In contrast with social role theory predictions, observers did not expect greater levels of sportsmanship from women compared to men. Yet observers expected more sportsmanship from women (a) when observers were ideologically motivated by gender-specific beliefs (gender-specific system justification; Study 1) and (b) when system justification was cued experimentally (Study 2). A heretofore-unexamined aspect, observers' ideology, modifies their expectations of sportsmanship citizenship across target genders. This has implications for system justification, social role, and organizational citizenship theoretical perspectives.

Quasiparticle engineering and entanglement propagation in a quantum many-body system.

PubMed

Jurcevic, P; Lanyon, B P; Hauke, P; Hempel, C; Zoller, P; Blatt, R; Roos, C F

2014-07-10

The key to explaining and controlling a range of quantum phenomena is to study how information propagates around many-body systems. Quantum dynamics can be described by particle-like carriers of information that emerge in the collective behaviour of the underlying system, the so-called quasiparticles. These elementary excitations are predicted to distribute quantum information in a fashion determined by the system's interactions. Here we report quasiparticle dynamics observed in a quantum many-body system of trapped atomic ions. First, we observe the entanglement distributed by quasiparticles as they trace out light-cone-like wavefronts. Second, using the ability to tune the interaction range in our system, we observe information propagation in an experimental regime where the effective-light-cone picture does not apply. Our results will enable experimental studies of a range of quantum phenomena, including transport, thermalization, localization and entanglement growth, and represent a first step towards a new quantum-optic regime of engineered quasiparticles with tunable nonlinear interactions.

A microfluidic co-culture system to monitor tumor-stromal interactions on a chip

PubMed Central

Menon, Nishanth V.; Cao, Bin; Lim, Mayasari; Kang, Yuejun

2014-01-01

The living cells are arranged in a complex natural environment wherein they interact with extracellular matrix and other neighboring cells. Cell-cell interactions, especially those between distinct phenotypes, have attracted particular interest due to the significant physiological relevance they can reveal for both fundamental and applied biomedical research. To study cell-cell interactions, it is necessary to develop co-culture systems, where different cell types can be cultured within the same confined space. Although the current advancement in lab-on-a-chip technology has allowed the creation of in vitro models to mimic the complexity of in vivo environment, it is still rather challenging to create such co-culture systems for easy control of different colonies of cells. In this paper, we have demonstrated a straightforward method for the development of an on-chip co-culture system. It involves a series of steps to selectively change the surface property for discriminative cell seeding and to induce cellular interaction in a co-culture region. Bone marrow stromal cells (HS5) and a liver tumor cell line (HuH7) have been used to demonstrate this co-culture model. The cell migration and cellular interaction have been analyzed using microscopy and biochemical assays. This co-culture system could be used as a disease model to obtain biological insight of pathological progression, as well as a tool to evaluate the efficacy of different drugs for pharmaceutical studies. PMID:25553194

Thermal transport through a spin-phonon interacting junction: A nonequilibrium Green's function method study

NASA Astrophysics Data System (ADS)

Zhang, Zu-Quan; Lü, Jing-Tao

2017-09-01

Using the nonequilibrium Green's function method, we consider heat transport in an insulating ferromagnetic spin chain model with spin-phonon interaction under an external magnetic field. Employing the Holstein-Primakoff transformation to the spin system, we treat the resulted magnon-phonon interaction within the self-consistent Born approximation. We find the magnon-phonon coupling can change qualitatively the magnon thermal conductance in the high-temperature regime. At a spectral mismatched ferromagnetic-normal insulator interface, we also find thermal rectification and negative differential thermal conductance due to the magnon-phonon interaction. We show that these effects can be effectively tuned by the external applied magnetic field, a convenient advantage absent in anharmonic phonon and electron-phonon systems studied before.

Controlled interaction: strategies for using virtual reality to study perception.

PubMed

Durgin, Frank H; Li, Zhi

2010-05-01

Immersive virtual reality systems employing head-mounted displays offer great promise for the investigation of perception and action, but there are well-documented limitations to most virtual reality systems. In the present article, we suggest strategies for studying perception/action interactions that try to depend on both scale-invariant metrics (such as power function exponents) and careful consideration of the requirements of the interactions under investigation. New data concerning the effect of pincushion distortion on the perception of surface orientation are presented, as well as data documenting the perception of dynamic distortions associated with head movements with uncorrected optics. A review of several successful uses of virtual reality to study the interaction of perception and action emphasizes scale-free analysis strategies that can achieve theoretical goals while minimizing assumptions about the accuracy of virtual simulations.

Nestedness across biological scales

PubMed Central

Marquitti, Flavia M. D.; Raimundo, Rafael L. G.; Sebastián-González, Esther; Coltri, Patricia P.; Perez, S. Ivan; Brandt, Débora Y. C.; Nunes, Kelly; Daura-Jorge, Fábio G.; Floeter, Sergio R.; Guimarães, Paulo R.

2017-01-01

Biological networks pervade nature. They describe systems throughout all levels of biological organization, from molecules regulating metabolism to species interactions that shape ecosystem dynamics. The network thinking revealed recurrent organizational patterns in complex biological systems, such as the formation of semi-independent groups of connected elements (modularity) and non-random distributions of interactions among elements. Other structural patterns, such as nestedness, have been primarily assessed in ecological networks formed by two non-overlapping sets of elements; information on its occurrence on other levels of organization is lacking. Nestedness occurs when interactions of less connected elements form proper subsets of the interactions of more connected elements. Only recently these properties began to be appreciated in one-mode networks (where all elements can interact) which describe a much wider variety of biological phenomena. Here, we compute nestedness in a diverse collection of one-mode networked systems from six different levels of biological organization depicting gene and protein interactions, complex phenotypes, animal societies, metapopulations, food webs and vertebrate metacommunities. Our findings suggest that nestedness emerge independently of interaction type or biological scale and reveal that disparate systems can share nested organization features characterized by inclusive subsets of interacting elements with decreasing connectedness. We primarily explore the implications of a nested structure for each of these studied systems, then theorize on how nested networks are assembled. We hypothesize that nestedness emerges across scales due to processes that, although system-dependent, may share a general compromise between two features: specificity (the number of interactions the elements of the system can have) and affinity (how these elements can be connected to each other). Our findings suggesting occurrence of nestedness throughout biological scales can stimulate the debate on how pervasive nestedness may be in nature, while the theoretical emergent principles can aid further research on commonalities of biological networks. PMID:28166284

Oxytocin-secreting system: A major part of the neuroendocrine center regulating immunologic activity.

PubMed

Wang, Ping; Yang, Hai-Peng; Tian, Shujun; Wang, Liwei; Wang, Stephani C; Zhang, Fengmin; Wang, Yu-Feng

2015-12-15

Interactions between the nervous system and immune system have been studied extensively. However, the mechanisms underlying the neural regulation of immune activity, particularly the neuroendocrine regulation of immunologic functions, remain elusive. In this review, we provide a comprehensive examination of current evidence on interactions between the immune system and hypothalamic oxytocin-secreting system. We highlight the fact that oxytocin may have significant effects in the body, beyond its classical functions in lactation and parturition. Similar to the hypothalamo-pituitary-adrenal axis, the oxytocin-secreting system closely interacts with classical immune system, integrating both neurochemical and immunologic signals in the central nervous system and in turn affects immunologic defense, homeostasis, and surveillance. Lastly, this review explores therapeutic potentials of oxytocin in treating immunologic disorders. Copyright © 2015 Elsevier B.V. All rights reserved.

DEEP SPACE: High Resolution VR Platform for Multi-user Interactive Narratives

NASA Astrophysics Data System (ADS)

Kuka, Daniela; Elias, Oliver; Martins, Ronald; Lindinger, Christopher; Pramböck, Andreas; Jalsovec, Andreas; Maresch, Pascal; Hörtner, Horst; Brandl, Peter

DEEP SPACE is a large-scale platform for interactive, stereoscopic and high resolution content. The spatial and the system design of DEEP SPACE are facing constraints of CAVETM-like systems in respect to multi-user interactive storytelling. To be used as research platform and as public exhibition space for many people, DEEP SPACE is capable to process interactive, stereoscopic applications on two projection walls with a size of 16 by 9 meters and a resolution of four times 1080p (4K) each. The processed applications are ranging from Virtual Reality (VR)-environments to 3D-movies to computationally intensive 2D-productions. In this paper, we are describing DEEP SPACE as an experimental VR platform for multi-user interactive storytelling. We are focusing on the system design relevant for the platform, including the integration of the Apple iPod Touch technology as VR control, and a special case study that is demonstrating the research efforts in the field of multi-user interactive storytelling. The described case study, entitled "Papyrate's Island", provides a prototypical scenario of how physical drawings may impact on digital narratives. In this special case, DEEP SPACE helps us to explore the hypothesis that drawing, a primordial human creative skill, gives us access to entirely new creative possibilities in the domain of interactive storytelling.

An Investigation of the Potential of Interactive Simulations for Developing System Thinking Skills in Elementary School: A Case Study with Fifth-Graders and Sixth-Graders

ERIC Educational Resources Information Center

Evagorou, Maria; Korfiatis, Kostas; Nicolaou, Christiana; Constantinou, Costas

2009-01-01

The purpose of this study was to investigate the impact of a simulation-based learning environment on elementary school students' (11-12 years old) development of system thinking skills. The learning environment included interactive simulations using the Stagecast Creator software to simulate the ecosystem of a marsh. Simulations are an important…

[Influences of environmental factors and interaction of several chemokines gene-environmental on systemic lupus erythematosus].

PubMed

Ye, Dong-qing; Hu, Yi-song; Li, Xiang-pei; Huang, Fen; Yang, Shi-gui; Hao, Jia-hu; Yin, Jing; Zhang, Guo-qing; Liu, Hui-hui

2004-11-01

To explore the impact of environmental factors, daily lifestyle, psycho-social factors and the interactions between environmental factors and chemokines genes on systemic lupus erythematosus (SLE). Case-control study was carried out and environmental factors for SLE were analyzed by univariate and multivariate unconditional logistic regression. Interactions between environmental factors and chemokines polymorphism contributing to systemic lupus erythematosus were also analyzed by logistic regression model. There were nineteen factors associated with SLE when univariate unconditional logistic regression was used. However, when multivariate unconditional logistic regression was used, only five factors showed having impacts on the disease, in which drinking well water (OR=0.099) was protective factor for SLE, and multiple drug allergy (OR=8.174), over-exposure to sunshine (OR=18.339), taking antibiotics (OR=9.630) and oral contraceptives were risk factors for SLE. When unconditional logistic regression model was used, results showed that there was interaction between eating irritable food and -2518MCP-1G/G genotype (OR=4.387). No interaction between environmental factors was found that contributing to SLE in this study. Many environmental factors were related to SLE, and there was an interaction between -2518MCP-1G/G genotype and eating irritable food.

Effective temperature in an interacting vertex system: theory and experiment on artificial spin ice.

PubMed

Nisoli, Cristiano; Li, Jie; Ke, Xianglin; Garand, D; Schiffer, Peter; Crespi, Vincent H

2010-07-23

Frustrated arrays of interacting single-domain nanomagnets provide important model systems for statistical mechanics, as they map closely onto well-studied vertex models and are amenable to direct imaging and custom engineering. Although these systems are manifestly athermal, we demonstrate that an effective temperature, controlled by an external magnetic drive, describes their microstates and therefore their full statistical properties.

Interdisciplinary Concepts for Design and Implementation of Mixed Reality Interactive Neurorehabilitation Systems for Stroke

PubMed Central

Lehrer, Nicole; Duff, Margaret; Venkataraman, Vinay; Turaga, Pavan; Ingalls, Todd; Rymer, W. Zev; Wolf, Steven L.; Rikakis, Thanassis

2015-01-01

Interactive neurorehabilitation (INR) systems provide therapy that can evaluate and deliver feedback on a patient's movement computationally. There are currently many approaches to INR design and implementation, without a clear indication of which methods to utilize best. This article presents key interactive computing, motor learning, and media arts concepts utilized by an interdisciplinary group to develop adaptive, mixed reality INR systems for upper extremity therapy of patients with stroke. Two INR systems are used as examples to show how the concepts can be applied within: (1) a small-scale INR clinical study that achieved integrated improvement of movement quality and functionality through continuously supervised therapy and (2) a pilot study that achieved improvement of clinical scores with minimal supervision. The notion is proposed that some of the successful approaches developed and tested within these systems can form the basis of a scalable design methodology for other INR systems. A coherent approach to INR design is needed to facilitate the use of the systems by physical therapists, increase the number of successful INR studies, and generate rich clinical data that can inform the development of best practices for use of INR in physical therapy. PMID:25425694

Interdisciplinary concepts for design and implementation of mixed reality interactive neurorehabilitation systems for stroke.

PubMed

Baran, Michael; Lehrer, Nicole; Duff, Margaret; Venkataraman, Vinay; Turaga, Pavan; Ingalls, Todd; Rymer, W Zev; Wolf, Steven L; Rikakis, Thanassis

2015-03-01

Interactive neurorehabilitation (INR) systems provide therapy that can evaluate and deliver feedback on a patient's movement computationally. There are currently many approaches to INR design and implementation, without a clear indication of which methods to utilize best. This article presents key interactive computing, motor learning, and media arts concepts utilized by an interdisciplinary group to develop adaptive, mixed reality INR systems for upper extremity therapy of patients with stroke. Two INR systems are used as examples to show how the concepts can be applied within: (1) a small-scale INR clinical study that achieved integrated improvement of movement quality and functionality through continuously supervised therapy and (2) a pilot study that achieved improvement of clinical scores with minimal supervision. The notion is proposed that some of the successful approaches developed and tested within these systems can form the basis of a scalable design methodology for other INR systems. A coherent approach to INR design is needed to facilitate the use of the systems by physical therapists, increase the number of successful INR studies, and generate rich clinical data that can inform the development of best practices for use of INR in physical therapy. © 2015 American Physical Therapy Association.

Emergent ultra–long-range interactions between active particles in hybrid active–inactive systems

PubMed Central

Steimel, Joshua P.; Aragones, Juan L.; Hu, Helen; Qureshi, Naser; Alexander-Katz, Alfredo

2016-01-01

Particle–particle interactions determine the state of a system. Control over the range of such interactions as well as their magnitude has been an active area of research for decades due to the fundamental challenges it poses in science and technology. Very recently, effective interactions between active particles have gathered much attention as they can lead to out-of-equilibrium cooperative states such as flocking. Inspired by nature, where active living cells coexist with lifeless objects and structures, here we study the effective interactions that appear in systems composed of active and passive mixtures of colloids. Our systems are 2D colloidal monolayers composed primarily of passive (inactive) colloids, and a very small fraction of active (spinning) ferromagnetic colloids. We find an emergent ultra–long-range attractive interaction induced by the activity of the spinning particles and mediated by the elasticity of the passive medium. Interestingly, the appearance of such interaction depends on the spinning protocol and has a minimum actuation timescale below which no attraction is observed. Overall, these results clearly show that, in the presence of elastic components, active particles can interact across very long distances without any chemical modification of the environment. Such a mechanism might potentially be important for some biological systems and can be harnessed for newer developments in synthetic active soft materials. PMID:27071096

Membrane Interaction of Antimicrobial Peptides Using E. coli Lipid Extract as Model Bacterial Cell Membranes and SFG Spectroscopy

PubMed Central

Soblosky, Lauren; Ramamoorthy, Ayyalusamy; Chen, Zhan

2015-01-01

Supported lipid bilayers are used as a convenient model cell membrane system to study biologically important molecule-lipid interactions in situ. However, the lipid bilayer models are often simple and the acquired results with these models may not provide all pertinent information related to a real cell membrane. In this work, we use sum frequency generation (SFG) vibrational spectroscopy to study molecular-level interactions between the antimicrobial peptides (AMPs) MSI-594, ovispirin-1 G18, magainin 2 and a simple 1,2-dipalmitoyl-d62-sn-glycero-3-phosphoglycerol (dDPPG)-1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) bilayer. We compared such interactions to those between the AMPs and a more complex dDPPG/E. coli polar lipid extract bilayer. We show that to fully understand more complex aspects of peptide-bilayer interaction, such as interaction kinetics, a heterogeneous lipid composition is required, such as the E. coli polar lipid extract. The discrepancy in peptide-bilayer interaction is likely due in part to the difference in bilayer charge between the two systems since highly negative charged lipids can promote more favorable electrostatic interactions between the peptide and lipid bilayer. Results presented in this paper indicate that more complex model bilayers are needed to accurately analyze peptide-cell membrane interactions and demonstrates the importance of using an appropriate lipid composition to study AMP interaction properties. PMID:25707312

Bispectral pairwise interacting source analysis for identifying systems of cross-frequency interacting brain sources from electroencephalographic or magnetoencephalographic signals

NASA Astrophysics Data System (ADS)

Chella, Federico; Pizzella, Vittorio; Zappasodi, Filippo; Nolte, Guido; Marzetti, Laura

2016-05-01

Brain cognitive functions arise through the coordinated activity of several brain regions, which actually form complex dynamical systems operating at multiple frequencies. These systems often consist of interacting subsystems, whose characterization is of importance for a complete understanding of the brain interaction processes. To address this issue, we present a technique, namely the bispectral pairwise interacting source analysis (biPISA), for analyzing systems of cross-frequency interacting brain sources when multichannel electroencephalographic (EEG) or magnetoencephalographic (MEG) data are available. Specifically, the biPISA makes it possible to identify one or many subsystems of cross-frequency interacting sources by decomposing the antisymmetric components of the cross-bispectra between EEG or MEG signals, based on the assumption that interactions are pairwise. Thanks to the properties of the antisymmetric components of the cross-bispectra, biPISA is also robust to spurious interactions arising from mixing artifacts, i.e., volume conduction or field spread, which always affect EEG or MEG functional connectivity estimates. This method is an extension of the pairwise interacting source analysis (PISA), which was originally introduced for investigating interactions at the same frequency, to the study of cross-frequency interactions. The effectiveness of this approach is demonstrated in simulations for up to three interacting source pairs and for real MEG recordings of spontaneous brain activity. Simulations show that the performances of biPISA in estimating the phase difference between the interacting sources are affected by the increasing level of noise rather than by the number of the interacting subsystems. The analysis of real MEG data reveals an interaction between two pairs of sources of central mu and beta rhythms, localizing in the proximity of the left and right central sulci.

Interactive lung segmentation in abnormal human and animal chest CT scans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kockelkorn, Thessa T. J. P., E-mail: thessa@isi.uu.nl; Viergever, Max A.; Schaefer-Prokop, Cornelia M.

2014-08-15

Purpose: Many medical image analysis systems require segmentation of the structures of interest as a first step. For scans with gross pathology, automatic segmentation methods may fail. The authors’ aim is to develop a versatile, fast, and reliable interactive system to segment anatomical structures. In this study, this system was used for segmenting lungs in challenging thoracic computed tomography (CT) scans. Methods: In volumetric thoracic CT scans, the chest is segmented and divided into 3D volumes of interest (VOIs), containing voxels with similar densities. These VOIs are automatically labeled as either lung tissue or nonlung tissue. The automatic labeling resultsmore » can be corrected using an interactive or a supervised interactive approach. When using the supervised interactive system, the user is shown the classification results per slice, whereupon he/she can adjust incorrect labels. The system is retrained continuously, taking the corrections and approvals of the user into account. In this way, the system learns to make a better distinction between lung tissue and nonlung tissue. When using the interactive framework without supervised learning, the user corrects all incorrectly labeled VOIs manually. Both interactive segmentation tools were tested on 32 volumetric CT scans of pigs, mice and humans, containing pulmonary abnormalities. Results: On average, supervised interactive lung segmentation took under 9 min of user interaction. Algorithm computing time was 2 min on average, but can easily be reduced. On average, 2.0% of all VOIs in a scan had to be relabeled. Lung segmentation using the interactive segmentation method took on average 13 min and involved relabeling 3.0% of all VOIs on average. The resulting segmentations correspond well to manual delineations of eight axial slices per scan, with an average Dice similarity coefficient of 0.933. Conclusions: The authors have developed two fast and reliable methods for interactive lung segmentation in challenging chest CT images. Both systems do not require prior knowledge of the scans under consideration and work on a variety of scans.« less

Population reversal driven by unrestrained interactions in molecular dynamics simulations: A dialanine model

NASA Astrophysics Data System (ADS)

Pullara, Filippo; Ignacio, J., General

2015-10-01

Standard Molecular Dynamics simulations (MD) are usually performed under periodic boundary conditions using the well-established "Ewald summation". This implies that the distance among each element in a given lattice cell and its corresponding element in another cell, as well as their relative orientations, are constant. Consequently, protein-protein interactions between proteins in different cells—important in many biological activities, such as protein cooperativity and physiological/pathological aggregation—are severely restricted, and features driven by protein-protein interactions are lost. The consequences of these restrictions, although conceptually understood and mentioned in the literature, have not been quantitatively studied before. The effect of protein-protein interactions on the free energy landscape of a model system, dialanine, is presented. This simple system features a free energy diagram with well-separated minima. It is found that, in the case of absence of peptide-peptide (p-p) interactions, the ψ = 150° dihedral angle determines the most energetically favored conformation (global free-energy minimum). When strong p-p interactions are induced, the global minimum switches to the ψ = 0° conformation. This shows that the free-energy landscape of an individual molecule is dramatically affected by the presence of other freely interacting molecules of its same type. Results of the study suggest how taking into account p-p interactions in MD allows having a more realistic picture of system activity and functional conformations.

[Advance in study of vascular endothelial cell and smooth muscle cell co-culture system].

PubMed

Li, Yujie; Yang, Qing; Weng, Xiaogang; Chen, Ying; Ruan, Congxiao; Li, Dan; Zhu, Xiaoxing

2012-02-01

The interactions between endothelial cells (EC) and smooth muscle cells (SMC) contribute to vascular physiological functions and also cause the occurrence and development of different kinds of diseases. Currently, EC-SMC co-culture model is the best way to study the interactions between the two kinds of cells. This article summarizes existing EC-SMC co-culture models and their effects on the structure and functions of the two kinds of cells. Microscopically speaking, it provides a basis for in-depth studies on their interactions as well as a reference for the establishment of in vitro EC-SMC co-culture system that is closer to organic physiology or pathology state.

Novel fusion protein approach for efficient high-throughput screening of small molecule-mediating protein-protein interactions in cells and living animals.

PubMed

Paulmurugan, Ramasamy; Gambhir, Sanjiv S

2005-08-15

Networks of protein interactions execute many different intracellular pathways. Small molecules either synthesized within the cell or obtained from the external environment mediate many of these protein-protein interactions. The study of these small molecule-mediated protein-protein interactions is important in understanding abnormal signal transduction pathways in a variety of disorders, as well as in optimizing the process of drug development and validation. In this study, we evaluated the rapamycin-mediated interaction of the human proteins FK506-binding protein (FKBP12) rapamycin-binding domain (FRB) and FKBP12 by constructing a fusion of these proteins with a split-Renilla luciferase or a split enhanced green fluorescent protein (split-EGFP) such that complementation of the reporter fragments occurs in the presence of rapamycin. Different linker peptides in the fusion protein were evaluated for the efficient maintenance of complemented reporter activity. This system was studied in both cell culture and xenografts in living animals. We found that peptide linkers with two or four EAAAR repeat showed higher protein-protein interaction-mediated signal with lower background signal compared with having no linker or linkers with amino acid sequences GGGGSGGGGS, ACGSLSCGSF, and ACGSLSCGSFACGSLSCGSF. A 9 +/- 2-fold increase in signal intensity both in cell culture and in living mice was seen compared with a system that expresses both reporter fragments and the interacting proteins separately. In this fusion system, rapamycin induced heterodimerization of the FRB and FKBP12 moieties occurred rapidly even at very lower concentrations (0.00001 nmol/L) of rapamycin. For a similar fusion system employing split-EGFP, flow cytometry analysis showed significant level of rapamycin-induced complementation.

System theoretic models for high density VLSI structures

NASA Astrophysics Data System (ADS)

Dickinson, Bradley W.; Hopkins, William E., Jr.

This research project involved the development of mathematical models for analysis, synthesis, and simulation of large systems of interacting devices. The work was motivated by problems that may become important in high density VLSI chips with characteristic feature sizes less than 1 micron: it is anticipated that interactions of neighboring devices will play an important role in the determination of circuit properties. It is hoped that the combination of high device densities and such local interactions can somehow be exploited to increase circuit speed and to reduce power consumption. To address these issues from the point of view of system theory, research was pursued in the areas of nonlinear and stochastic systems and into neural network models. Statistical models were developed to characterize various features of the dynamic behavior of interacting systems. Random process models for studying the resulting asynchronous modes of operation were investigated. The local interactions themselves may be modeled as stochastic effects. The resulting behavior was investigated through the use of various scaling limits, and by a combination of other analytical and simulation techniques. Techniques arising in a variety of disciplines where models of interaction were formulated and explored were considered and adapted for use.

The emerging genomics and systems biology research lead to systems genomics studies.

PubMed

Yang, Mary Qu; Yoshigoe, Kenji; Yang, William; Tong, Weida; Qin, Xiang; Dunker, A; Chen, Zhongxue; Arbania, Hamid R; Liu, Jun S; Niemierko, Andrzej; Yang, Jack Y

2014-01-01

Synergistically integrating multi-layer genomic data at systems level not only can lead to deeper insights into the molecular mechanisms related to disease initiation and progression, but also can guide pathway-based biomarker and drug target identification. With the advent of high-throughput next-generation sequencing technologies, sequencing both DNA and RNA has generated multi-layer genomic data that can provide DNA polymorphism, non-coding RNA, messenger RNA, gene expression, isoform and alternative splicing information. Systems biology on the other hand studies complex biological systems, particularly systematic study of complex molecular interactions within specific cells or organisms. Genomics and molecular systems biology can be merged into the study of genomic profiles and implicated biological functions at cellular or organism level. The prospectively emerging field can be referred to as systems genomics or genomic systems biology. The Mid-South Bioinformatics Centre (MBC) and Joint Bioinformatics Ph.D. Program of University of Arkansas at Little Rock and University of Arkansas for Medical Sciences are particularly interested in promoting education and research advancement in this prospectively emerging field. Based on past investigations and research outcomes, MBC is further utilizing differential gene and isoform/exon expression from RNA-seq and co-regulation from the ChiP-seq specific for different phenotypes in combination with protein-protein interactions, and protein-DNA interactions to construct high-level gene networks for an integrative genome-phoneme investigation at systems biology level.

Interaction between calcium and phosphate adsorption on goethite.

PubMed

Rietra, R P; Hiemstra, T; van Riemsdijk, W H

2001-08-15

Quantitatively, little is known about the ion interaction processes that are responsible for the binding of phosphate in soil, water, and sediment, which determine the bioavailability and mobility of phosphate. Studies have shown that metal hydroxides are often responsible for the binding of PO4 in soils and sediments, but the binding behavior of PO4 in these systems often differs significantly from adsorption studies on metal hydroxides in laboratory. The interaction between PO4 and Ca adsorption was studied on goethite because Ca can influence the PO4 adsorption equilibria. Since adsorption interactions are very difficult to discriminate from precipitation reactions, conditions were chosen to prevent precipitation of Ca-PO4 solids. Adsorption experiments of PO4 and Ca, individually and in combination, show a strong interaction between adsorbed Ca and PO4 on goethite for conditions below the saturation index of apatite. It is shown that it is possible to predict the adsorption and interaction of PO4 and Ca on electrostatic arguments using the model parameter values derived from the single-ion systems and without invoking ternary complex formation or precipitation. The model enables the prediction of the Ca-PO4 interaction for environmentally relevant calcium and phosphate concentrations.

Gender interaction in coed physical education: a study in Turkey.

PubMed

Koca, Canan

2009-01-01

Although there has been a long-standing debate about whether a single-sex or mixed-sex environment is better for students in many Western countries, coeducation is one of the taken-for-granted issues in the modern Turkish education system. This study examined commonly expressed concerns about gender equity in a mixed-sex environment within the context of physical education (PE) in Turkey. The purpose of the study was to examine teacher-student interaction in the coed PE classroom, focusing on gender-stereotyped beliefs. Participants consisted of two PE teachers and 37 eighth-grade students from a private school situated in suburban Ankara Turkey. The modified observational instrument with the combination of Teacher-Student Interaction (TSI) and Interactions for Sex Equity in Classroom Teaching Observation System (INTERSECT) was used to assess teacher-student interaction in the classroom. In order to understand students' and teachers' gender-stereotyped beliefs, individual interviews were also conducted. The findings of this study indicated that both male and female PE teachers interact more frequently with boys, and this interaction was influenced by gender-stereotyped beliefs of both teachers and students. In sum, similar to many other western countries, the movement toward coeducation in Turkey has not automatically brought equal opportunities for girls or boys in PE.

Route to thermalization in the α-Fermi–Pasta–Ulam system

PubMed Central

Onorato, Miguel; Vozella, Lara; Lvov, Yuri V.

2015-01-01

We study the original α-Fermi–Pasta–Ulam (FPU) system with N = 16, 32, and 64 masses connected by a nonlinear quadratic spring. Our approach is based on resonant wave–wave interaction theory; i.e., we assume that, in the weakly nonlinear regime (the one in which Fermi was originally interested), the large time dynamics is ruled by exact resonances. After a detailed analysis of the α-FPU equation of motion, we find that the first nontrivial resonances correspond to six-wave interactions. Those are precisely the interactions responsible for the thermalization of the energy in the spectrum. We predict that, for small-amplitude random waves, the timescale of such interactions is extremely large and it is of the order of 1/ϵ8, where ϵ is the small parameter in the system. The wave–wave interaction theory is not based on any threshold: Equipartition is predicted for arbitrary small nonlinearity. Our results are supported by extensive numerical simulations. A key role in our finding is played by the Umklapp (flip-over) resonant interactions, typical of discrete systems. The thermodynamic limit is also briefly discussed. PMID:25805822

Reconciling phase diffusion and Hartree-Fock approximation in condensate systems

NASA Astrophysics Data System (ADS)

Giorgi, Gian Luca; de Pasquale, Ferdinando

2012-01-01

Despite the weakly interacting regime, the physics of Bose-Einstein condensates is widely affected by particle-particle interactions. They determine quantum phase diffusion, which is known to be the main cause of loss of coherence. Studying a simple model of two interacting Bose systems, we show how to predict the appearance of phase diffusion beyond the Bogoliubov approximation, providing a self-consistent treatment in the framework of a generalized Hartree-Fock-Bogoliubov perturbation theory.

HPIminer: A text mining system for building and visualizing human protein interaction networks and pathways.

PubMed

Subramani, Suresh; Kalpana, Raja; Monickaraj, Pankaj Moses; Natarajan, Jeyakumar

2015-04-01

The knowledge on protein-protein interactions (PPI) and their related pathways are equally important to understand the biological functions of the living cell. Such information on human proteins is highly desirable to understand the mechanism of several diseases such as cancer, diabetes, and Alzheimer's disease. Because much of that information is buried in biomedical literature, an automated text mining system for visualizing human PPI and pathways is highly desirable. In this paper, we present HPIminer, a text mining system for visualizing human protein interactions and pathways from biomedical literature. HPIminer extracts human PPI information and PPI pairs from biomedical literature, and visualize their associated interactions, networks and pathways using two curated databases HPRD and KEGG. To our knowledge, HPIminer is the first system to build interaction networks from literature as well as curated databases. Further, the new interactions mined only from literature and not reported earlier in databases are highlighted as new. A comparative study with other similar tools shows that the resultant network is more informative and provides additional information on interacting proteins and their associated networks. Copyright © 2015 Elsevier Inc. All rights reserved.

Topological invariant and cotranslational symmetry in strongly interacting multi-magnon systems

NASA Astrophysics Data System (ADS)

Qin, Xizhou; Mei, Feng; Ke, Yongguan; Zhang, Li; Lee, Chaohong

2018-01-01

It is still an outstanding challenge to characterize and understand the topological features of strongly interacting states such as bound states in interacting quantum systems. Here, by introducing a cotranslational symmetry in an interacting multi-particle quantum system, we systematically develop a method to define a Chern invariant, which is a generalization of the well-known Thouless-Kohmoto-Nightingale-den Nijs invariant, for identifying strongly interacting topological states. As an example, we study the topological multi-magnon states in a generalized Heisenberg XXZ model, which can be realized by the currently available experiment techniques of cold atoms (Aidelsburger et al 2013 Phys. Rev. Lett. 111, 185301; Miyake et al 2013 Phys. Rev. Lett. 111, 185302). Through calculating the two-magnon excitation spectrum and the defined Chern number, we explore the emergence of topological edge bound states and give their topological phase diagram. We also analytically derive an effective single-particle Hofstadter superlattice model for a better understanding of the topological bound states. Our results not only provide a new approach to defining a topological invariant for interacting multi-particle systems, but also give insights into the characterization and understanding of strongly interacting topological states.

Local structure of ion pair interaction in lapatinib amorphous dispersions characterized by synchrotron x-ray diffraction and pair distribution function analysis

DOE PAGES

de Araujo, Gabriel L. B.; Benmore, Chris J.; Byrn, Stephen R.

2017-04-11

For many years, the idea of analyzing atom-atom contacts in amorphous drug-polymer systems has been of major interest, because this method has always had the potential to differentiate between amorphous systems with domains and amorphous systems which are molecular mixtures. In this study, local structure of ionic and noninonic interactions were studied by High-Energy X-ray Diffraction and Pair Distribution Function (PDF) analysis in amorphous solid dispersions of lapatinib in hypromellose phthalate (HPMCP) and hypromellose (HPMC-E3). The strategy of extracting lapatinib intermolecular drug interactions from the total PDF x-ray pattern was successfully applied allowing the detection of distinct nearest neighbor contactsmore » for the HPMC-E3 rich preparations showing that lapatinib molecules do not cluster in the same way as observed in HPMC-P, where ionic interactions are present. Orientational correlations up to nearest neighbor molecules at about 4.3 Å were observed for polymer rich samples; both observations showed strong correlation to the stability of the systems. Lasty, the superior physical stability of 1:3 LP:HPMCP was consistent with the absence of significant intermolecular interactions in (ΔD inter LP(r)) in the range of 3.0 to 6.0 Å, which are attributed to C-C, C-N and C-O nearest neighbor contacts present in drug-drug interactions.« less

Local structure of ion pair interaction in lapatinib amorphous dispersions characterized by synchrotron x-ray diffraction and pair distribution function analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

de Araujo, Gabriel L. B.; Benmore, Chris J.; Byrn, Stephen R.

For many years, the idea of analyzing atom-atom contacts in amorphous drug-polymer systems has been of major interest, because this method has always had the potential to differentiate between amorphous systems with domains and amorphous systems which are molecular mixtures. In this study, local structure of ionic and noninonic interactions were studied by High-Energy X-ray Diffraction and Pair Distribution Function (PDF) analysis in amorphous solid dispersions of lapatinib in hypromellose phthalate (HPMCP) and hypromellose (HPMC-E3). The strategy of extracting lapatinib intermolecular drug interactions from the total PDF x-ray pattern was successfully applied allowing the detection of distinct nearest neighbor contactsmore » for the HPMC-E3 rich preparations showing that lapatinib molecules do not cluster in the same way as observed in HPMC-P, where ionic interactions are present. Orientational correlations up to nearest neighbor molecules at about 4.3 Å were observed for polymer rich samples; both observations showed strong correlation to the stability of the systems. Lasty, the superior physical stability of 1:3 LP:HPMCP was consistent with the absence of significant intermolecular interactions in (ΔD inter LP(r)) in the range of 3.0 to 6.0 Å, which are attributed to C-C, C-N and C-O nearest neighbor contacts present in drug-drug interactions.« less

Local Structure of Ion Pair Interaction in Lapatinib Amorphous Dispersions characterized by Synchrotron X-Ray diffraction and Pair Distribution Function Analysis

NASA Astrophysics Data System (ADS)

de Araujo, Gabriel L. B.; Benmore, Chris J.; Byrn, Stephen R.

2017-04-01

For many years, the idea of analyzing atom-atom contacts in amorphous drug-polymer systems has been of major interest, because this method has always had the potential to differentiate between amorphous systems with domains and amorphous systems which are molecular mixtures. In this study, local structure of ionic and noninonic interactions were studied by High-Energy X-ray Diffraction and Pair Distribution Function (PDF) analysis in amorphous solid dispersions of lapatinib in hypromellose phthalate (HPMCP) and hypromellose (HPMC-E3). The strategy of extracting lapatinib intermolecular drug interactions from the total PDF x-ray pattern was successfully applied allowing the detection of distinct nearest neighbor contacts for the HPMC-E3 rich preparations showing that lapatinib molecules do not cluster in the same way as observed in HPMC-P, where ionic interactions are present. Orientational correlations up to nearest neighbor molecules at about 4.3 Å were observed for polymer rich samples; both observations showed strong correlation to the stability of the systems. Finally, the superior physical stability of 1:3 LP:HPMCP was consistent with the absence of significant intermolecular interactions in (Δ) in the range of 3.0 to 6.0 Å, which are attributed to C-C, C-N and C-O nearest neighbor contacts present in drug-drug interactions.

Effect of short range hydrodynamic on bimodal colloidal gel systems

NASA Astrophysics Data System (ADS)

Boromand, Arman; Jamali, Safa; Maia, Joao

2015-03-01

Colloidal Gels and disordered arrested systems has been studied extensively during the past decades. Although, they have found their place in multiple industries such as cosmetic, food and so on, their physical principals are still far beyond being understood. The interplay between different types of interactions from quantum scale, Van der Waals interaction, to short range interactions, depletion interaction, and long range interactions such as electrostatic double layer makes this systems challenging from simulation point of view. Many authors have implemented different simulation techniques such as molecular dynamics (MD) and Brownian dynamics (BD) to capture better picture during phase separation of colloidal system with short range attractive force. However, BD is not capable to include multi-body hydrodynamic interaction and MD is limited by the computational resources and is limited to short time and length scales. In this presentation we used Core-modified dissipative particle dynamics (CM-DPD) with modified depletion potential, as a coarse-grain model, to address the gel formation process in short ranged-attractive colloidal suspensions. Due to the possibility to include and separate short and long ranged-hydrodynamic forces in this method we studied the effect of each of those forces on the final morphology and report one of the controversial question in this field on the effect of hydrodynamics on the cluster formation process on bimodal, soft-hard colloidal mixtures.

Physicochemical characterization and study of in vitro interactions of pH-sensitive liposomes with the complement system.

PubMed

Carmo, Vildete A S; De Oliveira, Mônica C; Reis, Eduardo C O; Guimarães, Tânia M P D; Vilela, José M C; Andrade, Margareth S; Michalick, Marilene S M; Cardoso, Valbert N

2008-01-01

Complement activation is an important step in the acceleration of liposome clearance. The anaphylatoxins released following complement activation may motivate a wide variety of physiologic changes. We performed physicochemical characterization and in vitro studies of the interaction of complement system with both noncirculating and long-circulating pH-sensitive and nonpH-sensitive liposomes. The liposomes were characterized by diameter, zeta potential, and atomic force microscopy (AFM). The study of liposome interactions with complement system was conducted using hemolytic assay in rat serum. All liposomes presented a similar mean diameter (between 99.8 and 124.3 nm). The zeta potential was negative in all liposome preparations, except in liposomes modified with aminopoly (ethyleneglycol) 2000-distearoylphosphatidylethanolamine (aPEG(2000)-DSPE), which presented positive zeta potential. Atomic force microscopy images showed that non-long-circulating pH-sensitive liposomes are prone to vesicles aggregation. Non-pH-sensitive liposomes complement system activates, while pH-sensitive liposomes showed to be poor complement activators in rat serum.

Interacting lattice systems with quantum dissipation: A quantum Monte Carlo study

NASA Astrophysics Data System (ADS)

Yan, Zheng; Pollet, Lode; Lou, Jie; Wang, Xiaoqun; Chen, Yan; Cai, Zi

2018-01-01

Quantum dissipation arises when a large system can be split in a quantum system and an environment to which the energy of the former flows. Understanding the effect of dissipation on quantum many-body systems is of particular importance due to its potential relationship with quantum information. We propose a conceptually simple approach to introduce dissipation into interacting quantum systems in a thermodynamical context, in which every site of a one-dimensional (1D) lattice is coupled off-diagonally to its own bath. The interplay between quantum dissipation and interactions gives rise to counterintuitive interpretations such as a compressible zero-temperature state with spontaneous discrete symmetry breaking and a thermal phase transition in a 1D dissipative quantum many-body system as revealed by quantum Monte Carlo path-integral simulations.

Structural study of surfactant-dependent interaction with protein

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mehan, Sumit; Aswal, Vinod K., E-mail: vkaswal@barc.gov.in; Kohlbrecher, Joachim

2015-06-24

Small-angle neutron scattering (SANS) has been used to study the complex structure of anionic BSA protein with three different (cationic DTAB, anionic SDS and non-ionic C12E10) surfactants. These systems form very different surfactant-dependent complexes. We show that the structure of protein-surfactant complex is initiated by the site-specific electrostatic interaction between the components, followed by the hydrophobic interaction at high surfactant concentrations. It is also found that hydrophobic interaction is preferred over the electrostatic interaction in deciding the resultant structure of protein-surfactant complexes.

Structural study of surfactant-dependent interaction with protein

NASA Astrophysics Data System (ADS)

Mehan, Sumit; Aswal, Vinod K.; Kohlbrecher, Joachim

2015-06-01

Small-angle neutron scattering (SANS) has been used to study the complex structure of anionic BSA protein with three different (cationic DTAB, anionic SDS and non-ionic C12E10) surfactants. These systems form very different surfactant-dependent complexes. We show that the structure of protein-surfactant complex is initiated by the site-specific electrostatic interaction between the components, followed by the hydrophobic interaction at high surfactant concentrations. It is also found that hydrophobic interaction is preferred over the electrostatic interaction in deciding the resultant structure of protein-surfactant complexes.

Arabidopsis thaliana polyamine content is modified by the interaction with different Trichoderma species.

PubMed

Salazar-Badillo, Fatima Berenice; Sánchez-Rangel, Diana; Becerra-Flora, Alicia; López-Gómez, Miguel; Nieto-Jacobo, Fernanda; Mendoza-Mendoza, Artemio; Jiménez-Bremont, Juan Francisco

2015-10-01

Plants are associated with a wide range of microorganisms throughout their life cycle, and some interactions result on plant benefits. Trichoderma species are plant beneficial fungi that enhance plant growth and development, contribute to plant nutrition and induce defense responses. Nevertheless, the molecules involved in these beneficial effects still need to be identify. Polyamines are ubiquitous molecules implicated in plant growth and development, and in the establishment of plant microbe interactions. In this study, we assessed the polyamine profile in Arabidopsis plants during the interaction with Trichoderma virens and Trichoderma atroviride, using a system that allows direct plant-fungal contact or avoids their physical interaction (split system). The plantlets that grew in the split system exhibited higher biomass than the ones in direct contact with Trichoderma species. After 3 days of interaction, a significant decrease in Arabidopsis polyamine levels was observed in both systems (direct contact and split). After 5 days of interaction polyamine levels were increased. The highest levels were observed with T. atroviride (split system), and with T. virens (direct contact). The expression levels of Arabidopsis ADC1 and ADC2 genes during the interaction with the fungi were also assessed. We observed a time dependent regulation of ADC1 and ADC2 genes, which correlates with polyamine levels. Our data show an evident change in polyamine profile during Arabidopsis - Trichoderma interaction, accompanied by evident alterations in plant root architecture. Polyamines could be involved in the changes undergone by plant during the interaction with this beneficial fungus. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

A Systems Approach to Exposure Modeling (ExpoCast)(FutureTox3)

EPA Science Inventory

Systems Biology might be described as the understanding of how interactions on multiple scales integrate into a homeostatic system. Systems Toxicology could then be the study of the impact of chemical perturbations of homeostasis. Systems exposure might then be the study of the i...

Floquet prethermalization and regimes of heating in a periodically driven, interacting quantum system

NASA Astrophysics Data System (ADS)

Weidinger, Simon; Knap, Michael

We study the regimes of heating in the periodically driven O (N) -model, which represents a generic model for interacting quantum many-body systems. By computing the absorbed energy with a non-equilibrium Keldysh Green's function approach, we establish three dynamical regimes: at short times a single-particle dominated regime, at intermediate times a stable Floquet prethermal regime in which the system ceases to absorb, and at parametrically late times a thermalizing regime. Our simulations suggest that in the thermalizing regime the absorbed energy grows algebraically in time with an the exponent that approaches the universal value of 1 / 2 , and is thus significantly slower than linear Joule heating. Our results demonstrate the parametric stability of prethermal states in a generic many-body system driven at frequencies that are comparable to its microscopic scales. This paves the way for realizing exotic quantum phases, such as time crystals or interacting topological phases, in the prethermal regime of interacting Floquet systems. We acknowledge support from the Technical University of Munich - Institute for Advanced Study, funded by the German Excellence Initiative and the European Union FP7 under Grant agreement 291763, and from the DFG Grant No. KN 1254/1-1.

Interactive and Multimedia Contents Associated with a System for Computer-Aided Assessment

ERIC Educational Resources Information Center

Paiva, Rui C.; Ferreira, Milton S.; Mendes, Ana G.; Eusébio, Augusto M. J.

2015-01-01

This article presents a research study addressing the development, implementation, evaluation, and use of Interactive Modules for Online Training (MITO) of mathematics in higher education. This work was carried out in the context of the MITO project, which combined several features of the learning and management system Moodle, the computer-aided…

Project ITCH: Interactive Digital Simulation in Electrical Engineering Education.

ERIC Educational Resources Information Center

Bailey, F. N.; Kain, R. Y.

A two-stage project is investigating the educational potential of a low-cost time-sharing system used as a simulation tool in Electrical Engineering (EE) education. Phase I involves a pilot study and Phase II a full integration. The system employs interactive computer simulation to teach engineering concepts which are not well handled by…

Annehurst Curriculum Classification System Variables as Dimensions of Aptitude Treatment Interactions.

ERIC Educational Resources Information Center

Clark, Ginny; Grady, M. Tim

The objective of this study was to determine if the Annehurst Curriculum Classification System (ACCS) learner characteristics and curriculum materials classifications among elementary mathematics students, can be used as the dimensions of an aptitude-treatment interaction analysis. The subjects were 34 fourth and fifth graders in three open-space…

Effects of Storytelling to Facilitate EFL Speaking Using Web-Based Multimedia System

ERIC Educational Resources Information Center

Hwang, Wu-Yuin; Shadiev, Rustam; Hsu, Jung-Lung; Huang, Yueh-Min; Hsu, Guo-Liang; Lin, Yi-Chun

2016-01-01

This study applied storytelling in the English as a foreign language (EFL) classroom in order to promote speaking skills. Students were asked to practice speaking EFL through producing individual and interactive stories with a Web-based multimedia system. We aimed to investigate an effectiveness of applying individual and interactive storytelling…

Effects of Web-Based Interactive Modules on Engineering Students' Learning Motivations

ERIC Educational Resources Information Center

Bai, Haiyan; Aman, Amjad; Xu, Yunjun; Orlovskaya, Nina; Zhou, Mingming

2016-01-01

The purpose of this study is to assess the impact of a newly developed modules, Interactive Web-Based Visualization Tools for Gluing Undergraduate Fuel Cell Systems Courses system (IGLU), on learning motivations of engineering students using two samples (n[subscript 1] = 144 and n[subscript 2] = 135) from senior engineering classes. The…

Physical Foundations for Socio-Economic Modeling for Transportation Planning : Part 1. Interaction Between Urban Centers as a Potential Process.

DOT National Transportation Integrated Search

1977-09-01

The objective of this research is to make use of a physically based social system model to study the determinants of city sizes and their interactions in a nation. In particular, it was required that attention be paid to how new transportation system...

The Interactions between Problem Solving and Conceptual Change: System Dynamic Modelling as a Platform for Learning

ERIC Educational Resources Information Center

Lee, Chwee Beng

2010-01-01

This study examines the interactions between problem solving and conceptual change in an elementary science class where students build system dynamic models as a form of problem representations. Through mostly qualitative findings, we illustrate the interplay of three emerging intervening conditions (epistemological belief, structural knowledge…

Instructional Videos for Supporting Older Adults Who Use Interactive Systems

ERIC Educational Resources Information Center

Gramss, Denise; Struve, Doreen

2009-01-01

The study reported in this paper investigated the usefulness of different instructions for guiding inexperienced older adults through interactive systems. It was designed to compare different media in relation to their social as well as their motivational impact on the elderly during the learning process. Precisely, the video was compared with…

Novel approach using DNA-RNA hybrids in RNA nanotechnology | Center for Cancer Research

Cancer.gov

Developing simple approaches to detect interactions, modifications, and cellular locations of macromolecules is essential for understanding biochemical processes. The use of protein fragment complementation assays, also called split-protein systems, is a highly sensitive approach for studying protein interactions in biological systems. In this approach, functional proteins are

Multipeak low-temperature behavior of specific heat capacity in frustrated magnetic systems: An exact theoretical analysis

NASA Astrophysics Data System (ADS)

Jurčišinová, E.; Jurčišin, M.

2018-05-01

We investigate in detail the process of formation of the multipeak low-temperature structure in the behavior of the specific heat capacity in frustrated magnetic systems in the framework of the exactly solvable antiferromagnetic spin-1 /2 Ising model with the multisite interaction in the presence of the external magnetic field on the kagome-like Husimi lattice. The behavior of the entropy of the model is studied and exact values of the residual entropies of all ground states are found. It is shown that the multipeak structure in the behavior of the specific heat capacity is related to the formation of the multilevel hierarchical ordering in the system of all ground states of the model. Direct relation between the maximal number of peaks in the specific heat capacity behavior and the number of independent interactions in studied frustrated magnetic system is identified. The mechanism of the formation of the multipeak structure in the specific heat capacity is described and studied in detail, and it is generalized to frustrated magnetic systems with arbitrary numbers of independent interactions.

Closed-loop bird-computer interactions: a new method to study the role of bird calls.

PubMed

Lerch, Alexandre; Roy, Pierre; Pachet, François; Nagle, Laurent

2011-03-01

In the field of songbird research, many studies have shown the role of male songs in territorial defense and courtship. Calling, another important acoustic communication signal, has received much less attention, however, because calls are assumed to contain less information about the emitter than songs do. Birdcall repertoire is diverse, and the role of calls has been found to be significant in the area of social interaction, for example, in pair, family, and group cohesion. However, standard methods for studying calls do not allow precise and systematic study of their role in communication. We propose herein a new method to study bird vocal interaction. A closed-loop computer system interacts with canaries, Serinus canaria, by (1) automatically classifying two basic types of canary vocalization, single versus repeated calls, as they are produced by the subject, and (2) responding with a preprogrammed call type recorded from another bird. This computerized animal-machine interaction requires no human interference. We show first that the birds do engage in sustained interactions with the system, by studying the rate of single and repeated calls for various programmed protocols. We then show that female canaries differentially use single and repeated calls. First, they produce significantly more single than repeated calls, and second, the rate of single calls is associated with the context in which they interact, whereas repeated calls are context independent. This experiment is the first illustration of how closed-loop bird-computer interaction can be used productively to study social relationships. © Springer-Verlag 2010

Is There a Temperate Bias in Our Understanding of How Climate Change Will Alter Plant-Herbivore Interactions? A Meta-analysis of Experimental Studies.

PubMed

Mundim, Fabiane M; Bruna, Emilio M

2016-09-01

Climate change can drive major shifts in community composition and interactions between resident species. However, the magnitude of these changes depends on the type of interactions and the biome in which they take place. We review the existing conceptual framework for how climate change will influence tropical plant-herbivore interactions and formalize a similar framework for the temperate zone. We then conduct the first biome-specific tests of how plant-herbivore interactions change in response to climate-driven changes in temperature, precipitation, ambient CO2, and ozone. We used quantitative meta-analysis to compare predicted and observed changes in experimental studies. Empirical studies were heavily biased toward temperate systems, so testing predicted changes in tropical plant-herbivore interactions was virtually impossible. Furthermore, most studies investigated the effects of CO2 with limited plant and herbivore species. Irrespective of location, most studies manipulated only one climate change factor despite the fact that different factors can act in synergy to alter responses of plants and herbivores. Finally, studies of belowground plant-herbivore interactions were also rare; those conducted suggest that climate change could have major effects on belowground subsystems. Our results suggest that there is a disconnection between the growing literature proposing how climate change will influence plant-herbivore interactions and the studies testing these predictions. General conclusions will also be hampered without better integration of above- and belowground systems, assessing the effects of multiple climate change factors simultaneously, and using greater diversity of species in experiments.

Stochastic availability analysis of operational data systems in the Deep Space Network

NASA Technical Reports Server (NTRS)

Issa, T. N.

1991-01-01

Existing availability models of standby redundant systems consider only an operator's performance and its interaction with the hardware performance. In the case of operational data systems in the Deep Space Network (DSN), in addition to an operator system interface, a controller reconfigures the system and links a standby unit into the network data path upon failure of the operating unit. A stochastic (Markovian) process technique is used to model and analyze the availability performance and occurrence of degradation due to partial failures are quantitatively incorporated into the model. Exact expressions of the steady state availability and proportion degraded performance measures are derived for the systems under study. The interaction among the hardware, operator, and controller performance parameters and that interaction's effect on data availability are evaluated and illustrated for an operational data processing system.

Molecular electrostatics for probing lone pair-π interactions.

PubMed

Mohan, Neetha; Suresh, Cherumuttathu H; Kumar, Anmol; Gadre, Shridhar R

2013-11-14

An electrostatics-based approach has been proposed for probing the weak interactions between lone pair containing molecules and π deficient molecular systems. For electron-rich molecules, the negative minima in molecular electrostatic potential (MESP) topography give the location of electron localization and the MESP value at the minimum (Vmin) quantifies the electron-rich character of that region. Interactive behavior of a lone pair bearing molecule with electron deficient π-systems, such as hexafluorobenzene, 1,3,5-trinitrobenzene, 2,4,6-trifluoro-1,3,5-triazine and 1,2,4,5-tetracyanobenzene explored within DFT brings out good correlation of the lone pair-π interaction energy (E(int)) with the Vmin value of the electron-rich system. Such interaction is found to be portrayed well with the Electrostatic Potential for Intermolecular Complexation (EPIC) model. On the basis of the precise location of MESP minimum, a prediction for the orientation of a lone pair bearing molecule with an electron deficient π-system is possible in the majority of the cases studied.

Interaction, coalescence, and collapse of localized patterns in a quasi-one-dimensional system of interacting particles

NASA Astrophysics Data System (ADS)

Dessup, Tommy; Coste, Christophe; Saint Jean, Michel

2017-01-01

We study the path toward equilibrium of pairs of solitary wave envelopes (bubbles) that modulate a regular zigzag pattern in an annular channel. We evidence that bubble pairs are metastable states, which spontaneously evolve toward a stable single bubble. We exhibit the concept of topological frustration of a bubble pair. A configuration is frustrated when the particles between the two bubbles are not organized in a modulated staggered row. For a nonfrustrated (NF) bubble pair configuration, the bubbles interaction is attractive, whereas it is repulsive for a frustrated (F) configuration. We describe a model of interacting solitary wave that provides all qualitative characteristics of the interaction force: It is attractive for NF systems and repulsive for F systems and decreases exponentially with the bubbles distance. Moreover, for NF systems, the bubbles come closer and eventually merge as a single bubble, in a coalescence process. We also evidence a collapse process, in which one bubble shrinks in favor of the other one, overcoming an energetic barrier in phase space. This process is relevant for both NF systems and F systems. In NF systems, the coalescence prevails at low temperature, whereas thermally activated jumps make the collapse prevail at high temperature. In F systems, the path toward equilibrium involves a collapse process regardless of the temperature.

Review of Aerosol–Cloud Interactions: Mechanisms, Significance, and Challenges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fan, Jiwen; Wang, Yuan; Rosenfeld, Daniel

2016-11-01

Over the past decade, the number of studies that investigate aerosol-cloud interactions has increased considerably. Although tremendous progress has been made to improve our understanding of basic physical mechanisms of aerosol-cloud interactions and reduce their uncertainties in climate forcing, we are still in poor understanding of (1) some of the mechanisms that interact with each other over multiple spatial and temporal scales, (2) the feedback between microphysical and dynamical processes and between local-scale processes and large-scale circulations, and (3) the significance of cloud-aerosol interactions on weather systems as well as regional and global climate. This review focuses on recent theoreticalmore » studies and important mechanisms on aerosol-cloud interactions, and discusses the significances of aerosol impacts on raditative forcing and precipitation extremes associated with different cloud systems. Despite significant understanding has been gained about aerosol impacts on the main cloud types, there are still many unknowns especially associated with various deep convective systems. Therefore, large efforts are needed to escalate our understanding. Future directions should focus on obtaining concurrent measurements of aerosol properties, cloud microphysical and dynamic properties over a range of temporal and spatial scales collected over typical climate regimes and closure studies, as well as improving understanding and parameterizations of cloud microphysics such as ice nucleation, mixed-phase properties, and hydrometeor size and fall speed« less

Lipid packing determines protein-membrane interactions: challenges for apolipoprotein A–I and High Density Lipoproteins

PubMed Central

Sánchez, Susana A.; Tricerri, M. Alejandra; Ossato, Giulia; Gratton, Enrico

2010-01-01

Summary Protein and protein-lipid interactions, with and within specific areas in the cell membrane, are critical in order to modulate the cell signaling events required to maintain cell functions and viability. Biological bilayers are complex, dynamic platforms, and thus in vivo observations usually need to be preceded by studies on model systems that simplify and discriminate the different factors involved in lipid-protein interactions. Fluorescence microscopy studies using giant unilamellar vesicles (GUVs) as membrane model systems provide a unique methodology to quantify protein binding, interaction and lipid solubilization in artificial bilayers. The large size of lipid domains obtainable on GUVs, together with fluorescence microscopy techniques, provides the possibility to localize and quantify molecular interactions. FCS (Fluorescence Correlation Spectroscopy) can be performed using the GUV model to extract information on mobility and concentration. Two-photon Laurdan GP (Generalized Polarization) reports on local changes in membrane water content (related to membrane fluidity) due to protein binding or lipid removal from a given lipid domain. In this review, we summarize the experimental microscopy methods used to study the interaction of human apolipoprotein A–I (apoA-I) in lipid-free and lipid-bound conformations with bilayers and natural membranes. Results described here help us to understand cholesterol homeostasis, and offer a methodological design suited to different biological systems. PMID:20347719

Multidimensional approaches for studying plant defence against insects: from ecology to omics and synthetic biology.

PubMed

Barah, Pankaj; Bones, Atle M

2015-02-01

The biggest challenge for modern biology is to integrate multidisciplinary approaches towards understanding the organizational and functional complexity of biological systems at different hierarchies, starting from the subcellular molecular mechanisms (microscopic) to the functional interactions of ecological communities (macroscopic). The plant-insect interaction is a good model for this purpose with the availability of an enormous amount of information at the molecular and the ecosystem levels. Changing global climatic conditions are abruptly resetting plant-insect interactions. Integration of discretely located heterogeneous information from the ecosystem to genes and pathways will be an advantage to understand the complexity of plant-insect interactions. This review will present the recent developments in omics-based high-throughput experimental approaches, with particular emphasis on studying plant defence responses against insect attack. The review highlights the importance of using integrative systems approaches to study plant-insect interactions from the macroscopic to the microscopic level. We analyse the current efforts in generating, integrating and modelling multiomics data to understand plant-insect interaction at a systems level. As a future prospect, we highlight the growing interest in utilizing the synthetic biology platform for engineering insect-resistant plants. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Motivating forces of human actions. Neuroimaging reward and social interaction.

PubMed

Walter, Henrik; Abler, Birgit; Ciaramidaro, Angela; Erk, Susanne

2005-11-15

In neuroeconomics, reward and social interaction are central concepts to understand what motivates human behaviour. Both concepts are investigated in humans using neuroimaging methods. In this paper, we provide an overview about these results and discuss their relevance for economic behaviour. For reward it has been shown that a system exists in humans that is involved in predicting rewards and thus guides behaviour, involving a circuit including the striatum, the orbitofrontal cortex and the amygdala. Recent studies on social interaction revealed a mentalizing system representing the mental states of others. A central part of this system is the medial prefrontal cortex, in particular the anterior paracingulate cortex. The reward as well as the mentalizing system is engaged in economic decision-making. We will discuss implications of this study for neuromarketing as well as general implications of these results that may help to provide deeper insights into the motivating forces of human behaviour.

Structure and Dynamics of Antifreeze Protein--Model Membrane Interactions: A Combined Spectroscopic and Molecular Dynamics Study.

PubMed

Kar, Rajiv K; Mroue, Kamal H; Kumar, Dinesh; Tejo, Bimo A; Bhunia, Anirban

2016-02-11

Antifreeze proteins (AFPs) are the key biomolecules that enable species to survive under subzero temperature conditions. The physiologically relevant activities of AFPs are based on the adsorption to ice crystals, followed by the inhibition of subsequent crystal layer growth of ice, routed with depression in freezing point in a noncolligative manner. The functional attributes governing the mechanism by which AFPs inhibit freezing of body fluids in bacteria, fungi, plants, and fishes are mainly attributed to their adsorption onto the surface of ice within the physiological system. Importantly, AFPs are also known for their application in cryopreservation of biological samples that might be related to membrane interaction. To date, there is a paucity of information detailing the interaction of AFPs with membrane structures. Here, we focus on elucidating the biophysical properties of the interactions between AFPs and micelle models that mimic the membrane system. Micelle model systems of zwitterionic DPC and negatively charged SDS were utilized in this study, against which a significant interaction is experienced by two AFP molecules, namely, Peptide 1m and wfAFP (the popular AFP sourced from winter flounder). Using low- and high-resolution biophysical characterization techniques, such as circular dichroism (CD) and NMR spectroscopy, a strong evidence for the interactions of these AFPs with the membrane models is revealed in detail and is corroborated by in-depth residue-specific information derived from molecular dynamics simulation. Altogether, these results not only strengthen the fact that AFPs interact actively with membrane systems, but also demonstrate that membrane-associated AFPs are dynamic and capable of adopting a number of conformations rendering fluidity to the system.

Chromophore maturation and fluorescence fluctuation spectroscopy of fluorescent proteins in a cell-free expression system

PubMed Central

Macdonald, Patrick J.; Chen, Yan; Mueller, Joachim D.

2012-01-01

Cell-free synthesis, a method for the rapid expression of proteins, is increasingly used to study interactions of complex biological systems. GFP and its variants have become indispensable for fluorescence studies in live cells and are equally attractive as reporters for cell-free systems. This work investigates the use of fluorescence fluctuation spectroscopy (FFS) as a tool for quantitative analysis of protein interactions in cell-free expression systems. We also explore chromophore maturation of fluorescent proteins, which is of crucial importance for fluorescence studies. A droplet sample protocol was developed that ensured sufficient oxygenation for chromophore maturation and ease of manipulation for titration studies. The kinetics of chromophore maturation of EGFP, EYFP, and mCherry were analyzed as a function of temperature. A strong increase in the rate from room temperature to 37 °C was observed. We further demonstrate that all EGFP proteins fully mature in the cell-free solution and that brightness is a robust parameter specifying stoichiometry. Finally, FFS is applied to study the stoichiometry of the nuclear transport factor 2 in a cell-free system over a broad concentration range. We conclude that combining cell-free expression and FFS provides a powerful technique for quick, quantitative study of chromophore maturation and protein-protein interaction. PMID:22093611

Interaction between electrically charged droplets in microgravity

NASA Astrophysics Data System (ADS)

Brandenbourger, Martin; Caps, Herve; Hardouin, Jerome; Vitry, Youen; Boigelot, Bernard; Dorbolo, Stephane; Grasp Team; Beams Collaboration

2015-11-01

The past ten years, electrically charged droplets have been studied tremendously for their applications in industry (electrospray, electrowetting,...). However, charged droplets are also present in nature. Indeed, it has been shown that the droplets falling from thunderclouds possess an excess of electric charges. Moreover, some research groups try to use the electrical interaction between drops in order to control the coalescence between cloud droplets and control rain generation. The common way to study this kind of system is to make hypothesis on the interaction between two charged drops. Then, these hypothesis are extended to a system of thousands of charged droplets. Thanks to microgravity conditions, we were able to study the interaction between two electrically charged droplets. In practice, the charged droplets were propelled one in front of the other at low speed (less than 1 m/s). The droplets trajectory is studied for various charges and volumes. The repulsion between two charged drops is correctly fitted by a simple Coulomb repulsion law. In the case of attractive interactions, we discuss the collisions observed as a function of the droplets speed, volume and electric charges. Thanks to FNRS for financial support.

Analytical and numerical studies of Bose-Fermi mixtures in a one-dimensional harmonic trap

NASA Astrophysics Data System (ADS)

Dehkharghani, A. S.; Bellotti, F. F.; Zinner, N. T.

2017-07-01

In this paper we study a mixed system of bosons and fermions with up to six particles in total. All particles are assumed to have the same mass. The two-body interactions are repulsive and are assumed to have equal strength in both the Bose-Bose and the Fermi-Boson channels. The particles are confined externally by a harmonic oscillator one-body potential. For the case of four particles, two identical fermions and two identical bosons, we focus on the strongly interacting regime and analyze the system using both an analytical approach and density matrix renormalization group calculations using a discrete version of the underlying continuum Hamiltonian. This provides us with insight into both the ground state and the manifold of excited states that are almost degenerate for large interaction strength. Our results show great variation in the density profiles for bosons and fermions in different states for strongly interacting mixtures. By moving to slightly larger systems, we find that the ground state of balanced mixtures of four to six particles tends to separate bosons and fermions for strong (repulsive) interactions. On the other hand, in imbalanced Bose-Fermi mixtures we find pronounced odd-even effects in systems of five particles. These few-body results suggest that question of phase separation in one-dimensional confined mixtures are very sensitive to system composition, both for the ground state and the excited states.

Shock probes in a one-dimensional Katz-Lebowitz-Spohn model

NASA Astrophysics Data System (ADS)

Chatterjee, Sakuntala; Barma, Mustansir

2008-06-01

We consider shock probes in a one-dimensional driven diffusive medium with nearest-neighbor Ising interaction (KLS model). Earlier studies based on an approximate mapping of the present system to an effective zero-range process concluded that the exponents characterizing the decays of several static and dynamical correlation functions of the probes depend continuously on the strength of the Ising interaction. On the contrary, our numerical simulations indicate that over a substantial range of the interaction strength, these exponents remain constant and their values are the same as in the case of no interaction (when the medium executes an ASEP). We demonstrate this by numerical studies of several dynamical correlation functions for two probes and also for a macroscopic number of probes. Our results are consistent with the expectation that the short-ranged correlations induced by the Ising interaction should not affect the large time and large distance properties of the system, implying that scaling forms remain the same as in the medium with no interactions present.

Comparative study of binding interactions between porphyrin systems and aromatic compounds of biological importance by multiple spectroscopic techniques: A review.

PubMed

Makarska-Bialokoz, Magdalena

2018-07-05

The specific spectroscopic and redox properties of porphyrins predestine them to fulfill the role of sensors during interacting with different biologically active substances. Monitoring of binding interactions in the systems porphyrin-biologically active compound is a key question not only in the field of physiological functions of living organisms, but also in environmental protection, notably in the light of the rapidly growing drug consumption and concurrently the production of drug effluents. Not always beneficial action of drugs on natural porphyrin systems induces to further studies, with commercially available porphyrins as the model systems. Therefore the binding process between several water-soluble porphyrins and a series of biologically active compounds (e.g. caffeine, guanine, theophylline, theobromine, xanthine, uric acid) has been studied in different aqueous solutions analyzing their absorption and steady-state fluorescence spectra, the porphyrin fluorescence lifetimes and their quantum yields. The magnitude of the binding and fluorescence quenching constants values for particular quenchers decreases in a series: uric acid > guanine > caffeine > theophylline > theobromine > xanthine. In all the systems studied there are characters of static quenching, as a consequence of the π-π-stacked non-covalent and non-fluorescent complexes formation between porphyrins and interacting compounds, accompanied simultaneously by the additional specific binding interactions. The porphyrin fluorescence quenching can be explain by the photoinduced intermolecular electron transfer from aromatic compound to the center of the porphyrin molecule, playing the role of the binding site. Presented results can be valuable for designing of new fluorescent porphyrin chemosensors or monitoring of drug traces in aqueous solutions. The obtained outcomes have also the toxicological and medical importance, providing insight into the interactions of the water-soluble porphyrins with biologically active substances. Copyright © 2018 Elsevier B.V. All rights reserved.

Interacting complex systems: Theory and application to real-world situations

NASA Astrophysics Data System (ADS)

Piccinini, Nicola

The interest in complex systems has increased exponentially during the past years because it was found helpful in addressing many of today's challenges. The study of the brain, biology, earthquakes, markets and social sciences are only a few examples of the fields that have benefited from the investigation of complex systems. Internet, the increased mobility of people and the raising energy demand are among the factors that brought in contact complex systems that were isolated till a few years ago. A theory for the interaction between complex systems is becoming more and more urgent to help mankind in this transition. The present work builds upon the most recent results in this field by solving a theoretical problem that prevented previous work to be applied to important complex systems, like the brain. It also shows preliminary laboratory results of perturbation of in vitro neural networks that were done to test the theory. Finally, it gives a preview of the studies that are being done to create a theory that is even closer to the interaction between real complex systems.

Simulation of Quantum Many-Body Dynamics for Generic Strongly-Interacting Systems

NASA Astrophysics Data System (ADS)

Meyer, Gregory; Machado, Francisco; Yao, Norman

2017-04-01

Recent experimental advances have enabled the bottom-up assembly of complex, strongly interacting quantum many-body systems from individual atoms, ions, molecules and photons. These advances open the door to studying dynamics in isolated quantum systems as well as the possibility of realizing novel out-of-equilibrium phases of matter. Numerical studies provide insight into these systems; however, computational time and memory usage limit common numerical methods such as exact diagonalization to relatively small Hilbert spaces of dimension 215 . Here we present progress toward a new software package for dynamical time evolution of large generic quantum systems on massively parallel computing architectures. By projecting large sparse Hamiltonians into a much smaller Krylov subspace, we are able to compute the evolution of strongly interacting systems with Hilbert space dimension nearing 230. We discuss and benchmark different design implementations, such as matrix-free methods and GPU based calculations, using both pre-thermal time crystals and the Sachdev-Ye-Kitaev model as examples. We also include a simple symbolic language to describe generic Hamiltonians, allowing simulation of diverse quantum systems without any modification of the underlying C and Fortran code.

Update of KDBI: Kinetic Data of Bio-molecular Interaction database

PubMed Central

Kumar, Pankaj; Han, B. C.; Shi, Z.; Jia, J.; Wang, Y. P.; Zhang, Y. T.; Liang, L.; Liu, Q. F.; Ji, Z. L.; Chen, Y. Z.

2009-01-01

Knowledge of the kinetics of biomolecular interactions is important for facilitating the study of cellular processes and underlying molecular events, and is essential for quantitative study and simulation of biological systems. Kinetic Data of Bio-molecular Interaction database (KDBI) has been developed to provide information about experimentally determined kinetic data of protein–protein, protein–nucleic acid, protein–ligand, nucleic acid–ligand binding or reaction events described in the literature. To accommodate increasing demand for studying and simulating biological systems, numerous improvements and updates have been made to KDBI, including new ways to access data by pathway and molecule names, data file in System Biology Markup Language format, more efficient search engine, access to published parameter sets of simulation models of 63 pathways, and 2.3-fold increase of data (19 263 entries of 10 532 distinctive biomolecular binding and 11 954 interaction events, involving 2635 proteins/protein complexes, 847 nucleic acids, 1603 small molecules and 45 multi-step processes). KDBI is publically available at http://bidd.nus.edu.sg/group/kdbi/kdbi.asp. PMID:18971255

Analyte interactions with a new ditopic dansylamide-nitrobenzoxadiazole dyad: a combined photophysical, NMR, and theoretical (DFT) study.

PubMed

Bhoi, Abhas Kumar; Das, Sudhir Kumar; Majhi, Debashis; Sahu, Prabhat Kumar; Nijamudheen, A; N, Anoop; Rahaman, Abdur; Sarkar, Moloy

2014-08-21

We report herein the synthesis and photophysical studies on a new multicomponent chemosensor dyad comprising two fluorescing units, dansylamide (DANS) and nitrobenzoxadiazole (NBD). The system has been developed to investigate receptor-analyte binding interactions in the presence of both cations and anions in a single molecular system. A dimethyl amino (in the DANS unit) group is used as a receptor for cations, and acidic hydrogens of sulfonamide and the NBD group are used as receptors for anions. The system is characterized by conventional analytical techniques. The photophysical properties of this supramolecular system in the absence and presence of various metal ions and nonmetal ions as additives are investigated in an acetonitrile medium. Utility of this system in an aqueous medium has also been demonstrated. The absorption and fluorescence spectrum of the molecular system consists of a broad band typical of an intramolecular charge-transfer (ICT) transition. A low quantum yield and lifetime of the NBD moiety in the present dyad indicates photoinduced electron transfer (PET) between DANS and the NBD moiety. The fluorescence intensity of the system is found to decrease in the presence of fluoride and acetate anions; however, the quenching is found to be much higher for fluoride. This quenching behavior is attributed to the enhanced PET from the anion receptor to the fluorophore moiety. The mechanistic aspect of the fluoride ion signaling behavior has also been studied by infrared (IR) and (1)H NMR experiments. The hydrogen bonding interaction between the acidic NH protons of the DPN moiety and F(-) is found to be primarily responsible for the fluoride selective signaling behavior. While investigating the cation signaling behavior, contrary to anions, significant fluorescence enhancement has been observed only in the presence of transition-metal ions. This behavior is rationalized by considering the disruption of PET communication between DANS and the NBD moiety due to transition-metal ion binding. Theoretical (density functional theory) studies are also performed for the better understanding of the receptor-analyte interaction. Interestingly, negative cooperativity in binding is observed when the interaction of this system is studied in the presence of both Zn(2+) and F(-). Fluorescence microscopy studies also revealed that the newly developed fluorescent sensor system can be employed as an imaging probe in live cells.

Specific Recognition and Detection of MRSA Based on Molecular Probes Comprised of Lytic Phage and Antibody

DTIC Science & Technology

2011-03-29

QCM system was employed to study bacteria-phage interactions. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 1 18... QCM -D system (Sweden) was employed to study bacteria-phage interactions. Lytic phages were constructed into hollow spherical particles upon exposure to...a chloroform-water interface. These particles were converted into monolayers and deposited onto QCM -D crystals using Langmuir-Blodgett technique [I

The MV model of the color glass condensate for a finite number of sources including Coulomb interactions

DOE PAGES

McLerran, Larry; Skokov, Vladimir V.

2016-09-19

We modify the McLerran–Venugopalan model to include only a finite number of sources of color charge. In the effective action for such a system of a finite number of sources, there is a point-like interaction and a Coulombic interaction. The point interaction generates the standard fluctuation term in the McLerran–Venugopalan model. The Coulomb interaction generates the charge screening originating from well known evolution in x. Such a model may be useful for computing angular harmonics of flow measured in high energy hadron collisions for small systems. In this study we provide a basic formulation of the problem on a lattice.

Reducing Interaction Costs for Self-interested Agents

NASA Astrophysics Data System (ADS)

Zhang, Yunqi; Larson, Kate

In many multiagent systems, agents are not able to freely interact with each other or with a centralized mechanism. They may be limited in their interactions by cost or by the inherent structure of the system. Using a combinatorial auction application as motivation, we study the impact of interaction costs and structure on the strategic behaviour of self-interested agents. We present a particular model of costly agent-interaction, and argue that self-interested agents may wish to coordinate their actions with their neighbours so as to reduce their individual costs. We highlight the issues that arise in such a setting, propose a cost-sharing mechanism that agents can use, and discuss group coordination procedures. Experimental work validates our model.

CH/π Interactions in Carbohydrate Recognition.

PubMed

Spiwok, Vojtěch

2017-06-23

Many carbohydrate-binding proteins contain aromatic amino acid residues in their binding sites. These residues interact with carbohydrates in a stacking geometry via CH/π interactions. These interactions can be found in carbohydrate-binding proteins, including lectins, enzymes and carbohydrate transporters. Besides this, many non-protein aromatic molecules (natural as well as artificial) can bind saccharides using these interactions. Recent computational and experimental studies have shown that carbohydrate-aromatic CH/π interactions are dispersion interactions, tuned by electrostatics and partially stabilized by a hydrophobic effect in solvated systems.

Water interactions with hydrophobic groups: Assessment and recalibration of semiempirical molecular orbital methods

NASA Astrophysics Data System (ADS)

Marion, Antoine; Monard, Gérald; Ruiz-López, Manuel F.; Ingrosso, Francesca

2014-07-01

In this work, we present a study of the ability of different semiempirical methods to describe intermolecular interactions in water solution. In particular, we focus on methods based on the Neglect of Diatomic Differential Overlap approximation. Significant improvements of these methods have been reported in the literature in the past years regarding the description of non-covalent interactions. In particular, a broad range of methodologies has been developed to deal with the properties of hydrogen-bonded systems, with varying degrees of success. In contrast, the interactions between water and a molecule containing hydrophobic groups have been little analyzed. Indeed, by considering the potential energy surfaces obtained using different semiempirical Hamiltonians for the intermolecular interactions of model systems, we found that none of the available methods provides an entirely satisfactory description of both hydrophobic and hydrophilic interactions in water. In addition, a vibrational analysis carried out in a model system for these interactions, a methane clathrate cluster, showed that some recent methods cannot be used to carry out studies of vibrational properties. Following a procedure established in our group [M. I. Bernal-Uruchurtu, M. T. C. Martins-Costa, C. Millot, and M. F. Ruiz-López, J. Comput. Chem. 21, 572 (2000); W. Harb, M. I. Bernal-Uruchurtu, and M. F. Ruiz-López, Theor. Chem. Acc. 112, 204 (2004)], we developed new parameters for the core-core interaction terms based on fitting potential energy curves obtained at the MP2 level for our model system. We investigated the transferability of the new parameters to describe a system, having both hydrophilic and hydrophobic groups, interacting with water. We found that only by introducing two different sets of parameters for hydrophilic and hydrophobic hydrogen atom types we are able to match the features of the ab initio calculated properties. Once this assumption is made, a good agreement with the MP2 reference is achieved. The results reported in this work provide therefore a direction for future developments of semiempirical approaches that are still required to investigate chemical processes in biomolecules and in large disordered systems.

Elements of radiative interactions in gaseous systems

NASA Technical Reports Server (NTRS)

Tiwari, Surendra N.

1991-01-01

Basic formulations, analyses, and numerical procedures are presented to study radiative interactions in gray as well as nongray gases under different physical and flow conditions. After preliminary fluid-dynamical considerations, essential governing equations for radiative transport are presented that are applicable under local and nonlocal thermodynamic equilibrium conditions. Auxiliary relations for relaxation times and spectral absorption model are also provided. For specific applications, several simple gaseous systems are analyzed. The first system considered consists of a gas bounded by two parallel plates having the same temperature. For this system, both vibrational nonequilibrium effects and radiation conduction interactions are studied. The second system consists of fully developed laminar flow and heat transfer in a parallel plate duct under the boundary condition of a uniform surface heat flux. For this system, effects of gray surface emittance are studied. With the single exception of a circular geometry, the third system is identical to the second system. Here, the influence of nongray walls is also studied, and a correlation between the parallel plates and circular tube results is presented. The particular gases selected are CO, CO2, H2O, CH4, N2O, NH3, OH, and NO. The temperature and pressure range considered are 300 to 2000 K, and 0.1 to 100 atmosphere, respectively. Illustrative results obtained for different cases are discussed and some specific conclusions are provided.

Outcomes from building system courseware for teaching and testing in a discipline-based human structure curriculum.

PubMed

Reilly, Frank D

2011-01-01

This study investigated the educational benefits of system-based lecture notes and interactive learning objects in a peripheral nervous system component of a traditional first-year medical school human anatomy course. The impetus for the investigation was anecdotal evidence suggesting enhanced learner satisfaction with the learning resources. Retrospective review of existing data from 2006 to 2009 was undertaken to quantify (1) the effects of Web-based system courseware on examination item performance, and (2) differences among learner opinions regarding the benefit level of the five different types of interactive learning objects as evaluated by instructional design questionnaires. Interactive patient-based case studies (IPCS) and review games (Games), simulated interactive patients (SIP), flashcards, and unit quizzes (Quizzes) developed in-house have been peer-reviewed and published in MedEdPORTAL. Statistics included one-way analysis of variance, Tukey's post hoc test, and power meta-analysis (d). Examination item analysis scores remained significantly higher (P ≤ 0.05; d = 0.3938) for learners receiving the instructional treatment incorporating system-based lecture notes and interactive learning objects than for those not receiving this treatment. Using questionnaires with a five-point Likert scale, students reported favorably on the benefit level of all learning objects. They rated the SIP and IPCS significantly higher (P ≤0.05) and games significantly lower (P ≤ 0.05) than in previous years, indicating a change in learner preferences. This study reaffirms that online system-based instructional techniques improve student examination performance and overall student satisfaction. Learners indicated stronger preferences for SIP and IPCS over exercises encouraging passive memorization of anatomical content. Copyright © 2011 American Association of Anatomists.

Simulating the Interactions Among Land Use, Transportation ...

EPA Pesticide Factsheets

In most transportation studies, computer models that forecast travel behavior statistics for a future year use static projections of the spatial distribution of future population and employment growth as inputs. As a result, they are unable to account for the temporally dynamic and non-linear interactions among transportation, land use, and socioeconomic systems. System dynamics (SD) provides a common framework for modeling the complex interactions among transportation and other related systems. This study uses a SD model to simulate the cascading impacts of a proposed light rail transit (LRT) system in central North Carolina, USA. The Durham-Orange Light Rail Project (D-O LRP) SD model incorporates relationships among the land use, transportation, and economy sectors to simulate the complex feedbacks that give rise to the travel behavior changes forecasted by the region’s transportation model. This paper demonstrates the sensitivity of changes in travel behavior to the proposed LRT system and the assumptions that went into the transportation modeling, and compares those results to the impacts of an alternative fare-free transit system. SD models such as the D-O LRP SD model can complement transportation studies by providing valuable insight into the interdependent community systems that collectively contribute to travel behavior changes. Presented at the 35th International Conference of the System Dynamics Society in Cambridge, MA, July 18th, 2017

Toward a more complete understanding of noncovalent interactions involving aromatic rings.

PubMed

Wheeler, Steven E; Bloom, Jacob W G

2014-08-14

Noncovalent interactions involving aromatic rings, which include π-stacking interactions, anion-π interactions, and XH-π interactions, among others, are ubiquitous in chemical and biochemical systems. Despite dramatic advances in our understanding of these interactions over the past decade, many aspects of these noncovalent interactions have only recently been uncovered, with many questions remaining. We summarize our computational studies aimed at understanding the impact of substituents and heteroatoms on these noncovalent interactions. In particular, we discuss our local, direct interaction model of substituent effects in π-stacking interactions. In this model, substituent effects are dominated by electrostatic interactions of the local dipoles associated with the substituents and the electric field of the other ring. The implications of the local nature of substituent effects on π-stacking interactions in larger systems are discussed, with examples given for complexes with carbon nanotubes and a small graphene model, as well as model stacked discotic systems. We also discuss related issues involving the interpretation of electrostatic potential (ESP) maps. Although ESP maps are widely used in discussions of noncovalent interactions, they are often misinterpreted. Next, we provide an alternative explanation for the origin of anion-π interactions involving substituted benzenes and N-heterocycles, and show that these interactions are well-described by simple models based solely on charge-dipole interactions. Finally, we summarize our recent work on the physical nature of substituent effects in XH-π interactions. Together, these results paint a more complete picture of noncovalent interactions involving aromatic rings and provide a firm conceptual foundation for the rational exploitation of these interactions in a myriad of chemical contexts.

The role of the apelinergic and vasopressinergic systems in the regulation of the cardiovascular system and the pathogenesis of cardiovascular disease.

PubMed

Czarzasta, Katarzyna; Cudnoch-Jedrzejewska, Agnieszka

2014-01-01

Research studies indicate a role of the apelinergic and vasopressinergic systems both in the regulation of the cardiovascular system and the pathogenesis of CVD, including in such settings as obesity and stress. Based on these data, it may be suggested that interactions between these systems underlie numerous physiological and pathophysiological processes, some of them related to the cardiovascular system. Better understanding of the role of these systems and their interactions, both physiological and related to the pathogenesis of CVD, will allow further advances in prevention and drug therapy.

Regime shifts and panarchies in regional scale social-ecological water systems

PubMed Central

Gunderson, Lance; Cosens, Barbara A.; Chaffin, Brian C.; (Tom) Arnold, Craig A.; Fremier, Alexander K.; Garmestani, Ahjond S.; Craig, Robin Kundis; Gosnell, Hannah; Birge, Hannah E.; Allen, Craig R.; Benson, Melinda H.; Morrison, Ryan R.; Stone, Mark C.; Hamm, Joseph A.; Nemec, Kristine; Schlager, Edella; Llewellyn, Dagmar

2018-01-01

In this article we summarize histories of nonlinear, complex interactions among societal, legal, and ecosystem dynamics in six North American water basins, as they respond to changing climate. These case studies were chosen to explore the conditions for emergence of adaptive governance in heavily regulated and developed social-ecological systems nested within a hierarchical governmental system. We summarize resilience assessments conducted in each system to provide a synthesis and reference by the other articles in this special feature. We also present a general framework used to evaluate the interactions between society and ecosystem regimes and the governance regimes chosen to mediate those interactions. The case studies show different ways that adaptive governance may be triggered, facilitated, or constrained by ecological and/or legal processes. The resilience assessments indicate that complex interactions among the governance and ecosystem components of these systems can produce different trajectories, which include patterns of (a) development and stabilization, (b) cycles of crisis and recovery, which includes lurches in adaptation and learning, and (3) periods of innovation, novelty, and transformation. Exploration of cross scale (Panarchy) interactions among levels and sectors of government and society illustrate that they may constrain development trajectories, but may also provide stability during crisis or innovation at smaller scales; create crises, but may also facilitate recovery; and constrain system transformation, but may also provide windows of opportunity in which transformation, and the resources to accomplish it, may occur. The framework is the starting point for our exploration of how law might play a role in enhancing the capacity of social-ecological systems to adapt to climate change. PMID:29780427

Regime shifts and panarchies in regional scale social-ecological water systems.

PubMed

Gunderson, Lance; Cosens, Barbara A; Chaffin, Brian C; Tom Arnold, Craig A; Fremier, Alexander K; Garmestani, Ahjond S; Craig, Robin Kundis; Gosnell, Hannah; Birge, Hannah E; Allen, Craig R; Benson, Melinda H; Morrison, Ryan R; Stone, Mark C; Hamm, Joseph A; Nemec, Kristine; Schlager, Edella; Llewellyn, Dagmar

2017-03-17

In this article we summarize histories of nonlinear, complex interactions among societal, legal, and ecosystem dynamics in six North American water basins, as they respond to changing climate. These case studies were chosen to explore the conditions for emergence of adaptive governance in heavily regulated and developed social-ecological systems nested within a hierarchical governmental system. We summarize resilience assessments conducted in each system to provide a synthesis and reference by the other articles in this special feature. We also present a general framework used to evaluate the interactions between society and ecosystem regimes and the governance regimes chosen to mediate those interactions. The case studies show different ways that adaptive governance may be triggered, facilitated, or constrained by ecological and/or legal processes. The resilience assessments indicate that complex interactions among the governance and ecosystem components of these systems can produce different trajectories, which include patterns of (a) development and stabilization, (b) cycles of crisis and recovery, which includes lurches in adaptation and learning, and (3) periods of innovation, novelty, and transformation. Exploration of cross scale (Panarchy) interactions among levels and sectors of government and society illustrate that they may constrain development trajectories, but may also provide stability during crisis or innovation at smaller scales; create crises, but may also facilitate recovery; and constrain system transformation, but may also provide windows of opportunity in which transformation, and the resources to accomplish it, may occur. The framework is the starting point for our exploration of how law might play a role in enhancing the capacity of social-ecological systems to adapt to climate change.

Regime shifts and panarchies in regional scale social-ecological water systems

USGS Publications Warehouse

Gunderson, Lance; Cosens, Barbara; Chaffin, Brian C.; Arnold, Craig Anthony (Tony); Fremier, Alexander K.; Garmestani, Ahjond S.; Kundis Craig, Robin; Gosnell, Hannah; Birge, Hannah E.; Allen, Craig R.; Benson, Melinda H.; Morrison, Ryan R.; Stone, Mark; Hamm, Joseph A.; Nemec, Kristine T.; Schlager, Edella; Llewellyn, Dagmar

2017-01-01

In this article we summarize histories of nonlinear, complex interactions among societal, legal, and ecosystem dynamics in six North American water basins, as they respond to changing climate. These case studies were chosen to explore the conditions for emergence of adaptive governance in heavily regulated and developed social-ecological systems nested within a hierarchical governmental system. We summarize resilience assessments conducted in each system to provide a synthesis and reference by the other articles in this special feature. We also present a general framework used to evaluate the interactions between society and ecosystem regimes and the governance regimes chosen to mediate those interactions. The case studies show different ways that adaptive governance may be triggered, facilitated, or constrained by ecological and/or legal processes. The resilience assessments indicate that complex interactions among the governance and ecosystem components of these systems can produce different trajectories, which include patterns of (a) development and stabilization, (b) cycles of crisis and recovery, which includes lurches in adaptation and learning, and (3) periods of innovation, novelty, and transformation. Exploration of cross scale (Panarchy) interactions among levels and sectors of government and society illustrate that they may constrain development trajectories, but may also provide stability during crisis or innovation at smaller scales; create crises, but may also facilitate recovery; and constrain system transformation, but may also provide windows of opportunity in which transformation, and the resources to accomplish it, may occur. The framework is the starting point for our exploration of how law might play a role in enhancing the capacity of social-ecological systems to adapt to climate change.

Review of the systems biology of the immune system using agent-based models.

PubMed

Shinde, Snehal B; Kurhekar, Manish P

2018-06-01

The immune system is an inherent protection system in vertebrate animals including human beings that exhibit properties such as self-organisation, self-adaptation, learning, and recognition. It interacts with the other allied systems such as the gut and lymph nodes. There is a need for immune system modelling to know about its complex internal mechanism, to understand how it maintains the homoeostasis, and how it interacts with the other systems. There are two types of modelling techniques used for the simulation of features of the immune system: equation-based modelling (EBM) and agent-based modelling. Owing to certain shortcomings of the EBM, agent-based modelling techniques are being widely used. This technique provides various predictions for disease causes and treatments; it also helps in hypothesis verification. This study presents a review of agent-based modelling of the immune system and its interactions with the gut and lymph nodes. The authors also review the modelling of immune system interactions during tuberculosis and cancer. In addition, they also outline the future research directions for the immune system simulation through agent-based techniques such as the effects of stress on the immune system, evolution of the immune system, and identification of the parameters for a healthy immune system.

Development of a novel remote‐controlled and self‐contained audiovisual‐aided interactive system for immobilizing claustrophobic patients

PubMed Central

Ju, Harang; Kim, Siyong; Read, Paul; Trifiletti, Daniel; Harrell, Andrew; Libby, Bruce

2015-01-01

In radiotherapy, only a few immobilization systems, such as open‐face mask and head mold with a bite plate, are available for claustrophobic patients with a certain degree of discomfort. The purpose of this study was to develop a remote‐controlled and self‐contained audiovisual (AV)‐aided interactive system with the iPad mini with Retina display for intrafractional motion management in brain/H&N (head and neck) radiotherapy for claustrophobic patients. The self‐contained, AV‐aided interactive system utilized two tablet computers: one for AV‐aided interactive guidance for the subject and the other for remote control by an operator. The tablet for audiovisual guidance traced the motion of a colored marker using the built‐in front‐facing camera, and the remote control tablet at the control room used infrastructure Wi‐Fi networks for real‐time communication with the other tablet. In the evaluation, a programmed QUASAR motion phantom was used to test the temporal and positional accuracy and resolution. Position data were also obtained from ten healthy volunteers with and without guidance to evaluate the reduction of intrafractional head motion in simulations of a claustrophobic brain or H&N case. In the phantom study, the temporal and positional resolution was 24 Hz and 0.2 mm. In the volunteer study, the average superior–inferior and right–left displacement was reduced from 1.9 mm to 0.3 mm and from 2.2 mm to 0.2 mm with AV‐aided interactive guidance, respectively. The superior–inferior and right–left positional drift was reduced from 0.5 mm/min to 0.1 mm/min and from 0.4 mm/min to 0.04 mm/min with audiovisual‐aided interactive guidance. This study demonstrated a reduction in intrafractional head motion using a remote‐controlled and self‐contained AV‐aided interactive system of iPad minis with Retina display, easily obtainable and cost‐effective tablet computers. This approach can potentially streamline clinical flow for claustrophobic patients without a head mask and also allows patients to practice self‐motion management before radiation treatment delivery. PACS number: 87.55.Gh

Primary reaction control system/remote manipulator system interaction with loaded arm. Space shuttle engineering and operations support

NASA Technical Reports Server (NTRS)

Taylor, E. C.; Davis, J. D.

1978-01-01

A study of the interaction between the orbiter primary reaction control system (PRCS) and the remote manipulator system (RMS) with a loaded arm is documented. This analysis was performed with the Payload Deployment and Retrieval Systems Simulation (PDRSS) program with the passive arm bending option. The passive-arm model simulates the arm as massless elastic links with locked joints. The study was divided into two parts. The first part was the evaluation of the response of the arm to step inputs (i.e. constant jet torques) about each of the orbiter body axes. The second part of the study was the evaluation of the response of the arm to minimum impulse primary RCS jet firings with both single pulse and pulse train inputs.

Towards rationally redesigning bacterial signaling systems using information encoded in abundant sequence data

NASA Astrophysics Data System (ADS)

Cheng, Ryan; Morcos, Faruck; Levine, Herbert; Onuchic, Jose

2014-03-01

An important challenge in biology is to distinguish the subset of residues that allow bacterial two-component signaling (TCS) proteins to preferentially interact with their correct TCS partner such that they can bind and transfer signal. Detailed knowledge of this information would allow one to search sequence-space for mutations that can systematically tune the signal transmission between TCS partners as well as re-encode a TCS protein to preferentially transfer signals to a non-partner. Motivated by the notion that this detailed information is found in sequence data, we explore the mutual sequence co-evolution between signaling partners to infer how mutations can positively or negatively alter their interaction. Using Direct Coupling Analysis (DCA) for determining evolutionarily conserved interprotein interactions, we apply a DCA-based metric to quantify mutational changes in the interaction between TCS proteins and demonstrate that it accurately correlates with experimental mutagenesis studies probing the mutational change in the in vitro phosphotransfer. Our methodology serves as a potential framework for the rational design of TCS systems as well as a framework for the system-level study of protein-protein interactions in sequence-rich systems. This research has been supported by the NSF INSPIRE award MCB-1241332 and by the CTBP sponsored by the NSF (Grant PHY-1308264).

Regime shifts and panarchies in regional scale social ...

EPA Pesticide Factsheets

In this article we summarize histories of nonlinear, complex interactions among societal, legal, and ecosystem dynamics in six North American water basins, as they respond to changing climate. These case studies were chosen to explore the conditions for emergence of adaptive governance in heavily regulated and developed social-ecological systems nested within a hierarchical governmental system. We summarize resilience assessments conducted in each system to provide a synthesis and reference by the other articles in this special feature. We also present a general framework used to evaluate the interactions between society and ecosystem regimes and the governance regimes chosen to mediate those interactions. The case studies show different ways that adaptive governance may be triggered, facilitated, or constrained by ecological and/or legal processes. The resilience assessments indicate that complex interactions among the governance and ecosystem components of these systems can produce different trajectories, which include patterns of (a) development and stabilization, (b) cycles of crisis and recovery, which includes lurches in adaptation and learning, and (3) periods of innovation, novelty, and transformation. Exploration of cross scale (Panarchy) interactions among levels and sectors of government and society illustrate that they may constrain development trajectories, but may also provide stability during crisis or innovation at smaller scales; create crises,

Studies on pharmacokinetic drug interaction potential of vinpocetine

USDA-ARS?s Scientific Manuscript database

Background: Vinpocetine, a semi-synthetic derivative of vincamine, is a popular dietary supplement used for the treatment of several central nervous system related disorders. Despite its wide use, no pharmacokinetic drug interaction studies are reported in literature. Due to increasing use of dietar...

Protein-protein interactions: an application of Tus-Ter mediated protein microarray system.

PubMed

Sitaraman, Kalavathy; Chatterjee, Deb K

2011-01-01

In this chapter, we present a novel, cost-effective microarray strategy that utilizes expression-ready plasmid DNAs to generate protein arrays on-demand and its use to validate protein-protein interactions. These expression plasmids were constructed in such a way so as to serve a dual purpose of synthesizing the protein of interest as well as capturing the synthesized protein. The microarray system is based on the high affinity binding of Escherichia coli "Tus" protein to "Ter," a 20 bp DNA sequence involved in the regulation of DNA replication. The protein expression is carried out in a cell-free protein synthesis system, with rabbit reticulocyte lysates, and the target proteins are detected either by labeled incorporated tag specific or by gene-specific antibodies. This microarray system has been successfully used for the detection of protein-protein interaction because both the target protein and the query protein can be transcribed and translated simultaneously in the microarray slides. The utility of this system for detecting protein-protein interaction is demonstrated by a few well-known examples: Jun/Fos, FRB/FKBP12, p53/MDM2, and CDK4/p16. In all these cases, the presence of protein complexes resulted in the localization of fluorophores at the specific sites of the immobilized target plasmids. Interestingly, during our interactions studies we also detected a previously unknown interaction between CDK2 and p16. Thus, this Tus-Ter based system of protein microarray can be used for the validation of known protein interactions as well as for identifying new protein-protein interactions. In addition, it can be used to examine and identify targets of nucleic acid-protein, ligand-receptor, enzyme-substrate, and drug-protein interactions.

Theoretical study on the interactions between chlordecone hydrate and acidic surface groups of activated carbon under basic pH conditions.

PubMed

Melchor-Rodríguez, Kenia; Gamboa-Carballo, Juan José; Ferino-Pérez, Anthuan; Passé-Coutrin, Nady; Gaspard, Sarra; Jáuregui-Haza, Ulises Javier

2018-05-01

A theoretical study of the influence of acidic surface groups (SG) of activated carbon (AC) on chlordecone hydrate (CLDh) adsorption is presented, in order to help understanding the adsorption process under basic pH conditions. A seven rings aromatic system (coronene) with a functional group in the edge was used as a simplified model of AC to evaluate the influence of SG in the course of adsorption from aqueous solution at basic pH conditions. Two SG were modeled in their deprotonated form: carboxyl and hydroxyl (COO - and O - ), interacting with CLDh. In order to model the solvation process, all systems under study were calculated with up to three water molecules. Multiple Minima Hypersurface (MMH) methodology was employed to study the interactions of CLDh with SG on AC using PM7 semiempirical Hamiltonian, to explore the potential energy surfaces of the systems and evaluate their thermodynamic association energies. The re-optimization of representative structures obtained from MMH was done using M06-2X Density Functional Theory. The Quantum Theory of Atoms in Molecules (QTAIM) was used to characterize the interaction types. As result, the association of CLDh with acidic SG at basic pH conditions preferentially occurs between the two alcohol groups of CLDh with COO - and O - groups and by dispersive interactions of chlorine atoms of CLDh with the graphitic surface. On the other hand, the presence of covalent interactions between the negatively charged oxygen of SG and one hydrogen atom of CLDh alcohol groups (O - ⋯HO interactions) without water molecules, was confirmed by QTAIM study. It can be concluded that the interactions of CLDh with acidic SG of AC under basic pH conditions confirms the physical mechanisms of adsorption process. Copyright © 2018 Elsevier Inc. All rights reserved.

Continuous time random walk with local particle-particle interaction

NASA Astrophysics Data System (ADS)

Xu, Jianping; Jiang, Guancheng

2018-05-01

The continuous time random walk (CTRW) is often applied to the study of particle motion in disordered media. Yet most such applications do not allow for particle-particle (walker-walker) interaction. In this paper, we consider a CTRW with particle-particle interaction; however, for simplicity, we restrain the interaction to be local. The generalized Chapman-Kolmogorov equation is modified by introducing a perturbation function that fluctuates around 1, which models the effect of interaction. Subsequently, a time-fractional nonlinear advection-diffusion equation is derived from this walking system. Under the initial condition of condensed particles at the origin and the free-boundary condition, we numerically solve this equation with both attractive and repulsive particle-particle interactions. Moreover, a Monte Carlo simulation is devised to verify the results of the above numerical work. The equation and the simulation unanimously predict that this walking system converges to the conventional one in the long-time limit. However, for systems where the free-boundary condition and long-time limit are not simultaneously satisfied, this convergence does not hold.

Path-integral Monte Carlo method for Rényi entanglement entropies.

PubMed

Herdman, C M; Inglis, Stephen; Roy, P-N; Melko, R G; Del Maestro, A

2014-07-01

We introduce a quantum Monte Carlo algorithm to measure the Rényi entanglement entropies in systems of interacting bosons in the continuum. This approach is based on a path-integral ground state method that can be applied to interacting itinerant bosons in any spatial dimension with direct relevance to experimental systems of quantum fluids. We demonstrate how it may be used to compute spatial mode entanglement, particle partitioned entanglement, and the entanglement of particles, providing insights into quantum correlations generated by fluctuations, indistinguishability, and interactions. We present proof-of-principle calculations and benchmark against an exactly soluble model of interacting bosons in one spatial dimension. As this algorithm retains the fundamental polynomial scaling of quantum Monte Carlo when applied to sign-problem-free models, future applications should allow for the study of entanglement entropy in large-scale many-body systems of interacting bosons.

Quantum Bose-Hubbard model with an evolving graph as a toy model for emergent spacetime

NASA Astrophysics Data System (ADS)

Hamma, Alioscia; Markopoulou, Fotini; Lloyd, Seth; Caravelli, Francesco; Severini, Simone; Markström, Klas

2010-05-01

We present a toy model for interacting matter and geometry that explores quantum dynamics in a spin system as a precursor to a quantum theory of gravity. The model has no a priori geometric properties; instead, locality is inferred from the more fundamental notion of interaction between the matter degrees of freedom. The interaction terms are themselves quantum degrees of freedom so that the structure of interactions and hence the resulting local and causal structures are dynamical. The system is a Hubbard model where the graph of the interactions is a set of quantum evolving variables. We show entanglement between spatial and matter degrees of freedom. We study numerically the quantum system and analyze its entanglement dynamics. We analyze the asymptotic behavior of the classical model. Finally, we discuss analogues of trapped surfaces and gravitational attraction in this simple model.

CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Depletion interactions in a cylindric pipeline

NASA Astrophysics Data System (ADS)

Huang, Li-Xin; Gao, Hai-Xia; Li, Chun-Shu; Xiao, Chang-Ming

2009-08-01

In a colloidal system confined by a small cylindric pipeline, the depletion interaction between two large spheres is different to the system confined by two plates, and the influence on depletion interaction from the pipeline is related to both the size and shape of it. In this paper, the depletion interactions in the systems confined by pipelines of different sizes or different shapes are studied by Monte Carlo simulations. The numerical results show that the influence on depletion force from the cylindric pipeline is stronger than that from two parallel plates, and the depletion force will be strengthened when the diameter of the cylinder is decreased. In addition, we also find that the depletion interaction is rather affected if the shape change of the pipeline is slightly changed, and the influence on depletion force from the shape change is stronger than that from the size change.

Analysis of airframe/engine interactions - An integrated control perspective

NASA Technical Reports Server (NTRS)

Schmidt, David K.; Schierman, John D.; Garg, Sanjay

1990-01-01

Techniques for the analysis of the dynamic interactions between airframe/engine dynamical systems are presented. Critical coupling terms are developed that determine the significance of these interactions with regard to the closed loop stability and performance of the feedback systems. A conceptual model is first used to indicate the potential sources of the coupling, how the coupling manifests itself, and how the magnitudes of these critical coupling terms are used to quantify the effects of the airframe/engine interactions. A case study is also presented involving an unstable airframe with thrust vectoring for attitude control. It is shown for this system with classical, decentralized control laws that there is little airframe/engine interaction, and the stability and performance with those control laws is not affected. Implications of parameter uncertainty in the coupling dynamics is also discussed, and effects of these parameter variations are also demonstrated to be small for this vehicle configuration.

Protein–protein interactions and selection: yeast-based approaches that exploit guanine nucleotide-binding protein signaling.

PubMed

Ishii, Jun; Fukuda, Nobuo; Tanaka, Tsutomu; Ogino, Chiaki; Kondo, Akihiko

2010-05-01

For elucidating protein–protein interactions, many methodologies have been developed during the past two decades. For investigation of interactions inside cells under physiological conditions, yeast is an attractive organism with which to quickly screen for hopeful candidates using versatile genetic technologies, and various types of approaches are now available.Among them, a variety of unique systems using the guanine nucleotide-binding protein (G-protein) signaling pathway in yeast have been established to investigate the interactions of proteins for biological study and pharmaceutical research. G-proteins involved in various cellular processes are mainly divided into two groups: small monomeric G-proteins,and heterotrimeric G-proteins. In this minireview, we summarize the basic principles and applications of yeast-based screening systems, using these two types of G-protein, which are typically used for elucidating biological protein interactions but are differentiated from traditional yeast two-hybrid systems.

Elasticity-induced force reversal between active spinning particles in dense passive media

PubMed Central

Aragones, J. L.; Steimel, J. P.; Alexander-Katz, A.

2016-01-01

The self-organization of active particles is governed by their dynamic effective interactions. Such interactions are controlled by the medium in which such active agents reside. Here we study the interactions between active agents in a dense non-active medium. Our system consists of actuated, spinning, active particles embedded in a dense monolayer of passive, or non-active, particles. We demonstrate that the presence of the passive monolayer alters markedly the properties of the system and results in a reversal of the forces between active spinning particles from repulsive to attractive. The origin of such reversal is due to the coupling between the active stresses and elasticity of the system. This discovery provides a mechanism for the interaction between active agents in complex and structured media, opening up opportunities to tune the interaction range and directionality via the mechanical properties of the medium. PMID:27112961

Crew/computer communications study. Volume 1: Final report. [onboard computerized communications system for spacecrews

NASA Technical Reports Server (NTRS)

Johannes, J. D.

1974-01-01

Techniques, methods, and system requirements are reported for an onboard computerized communications system that provides on-line computing capability during manned space exploration. Communications between man and computer take place by sequential execution of each discrete step of a procedure, by interactive progression through a tree-type structure to initiate tasks or by interactive optimization of a task requiring man to furnish a set of parameters. Effective communication between astronaut and computer utilizes structured vocabulary techniques and a word recognition system.

Spin Hamiltonian Analysis of the SMM V15 Using High Field ESR

NASA Astrophysics Data System (ADS)

Martens, Mathew; van Tol, Hans; Bertaina, Sylvain; Barbara, Bernard; Muller, Achim; Chiorescu, Irinel

2014-03-01

We have studied molecular magnets using high field / high frequency Electron Spin Resonance. Such molecular structures contain many quantum spins linked by exchange interactions and consequently their energy structure is often complex and require a good understanding of the molecular spin Hamiltonian. In particular, we studied the V15 molecule, comprised of 15 spins 1/2 and a total spin 1/2, which is a system that recently showed quantum Rabi oscillations of its total quantum spin. This type of molecule is an essential system for advancing molecular structures into quantum computing. We used high frequency characterization techniques (of hundreds of GHz) to gain insight into the exchange anisotropy interactions, crystal field, and anti-symmetric interactions present in this system. We analyzed the data using a detailed numerical analysis of spin interactions and our findings regarding the V15 spin Hamiltonian will be discussed. Supported by the NSF Cooperative Agreement Grant No. DMR-0654118 and No. NHMFL UCGP 5059, NSF grant No. DMR-0645408.

Mutual interactions of redox couples via electron exchange in silicate melts - Models for geochemical melt systems

NASA Technical Reports Server (NTRS)

Schreiber, Henry D.; Merkel, Robert C., Jr.; Schreiber, V. Lea; Balazs, G. Bryan

1987-01-01

The mutual interactions via electron exchange of redox couples in glass-forming melts were investigated both theoretically and experimentally. A thermodynamic approach for considering the mutual interactions leads to conclusion that the degree of mutual interaction in the melt should be proportional in part to the difference in relative reduction potentials of the interacting redox couples. Experimental studies verify this conclusion for numerous redox couples in several composition/temperature/oxygen fugacity regimes. Geochemical systems simultaneously possess many potentially multivalent elements; the stabilized redox states in the resulting magmas can be explained in part by mutual interactions and by redox buffering through the central Fe(III)- Fe(II) couples in the melts. The significance of these results for basaltic magmas of the earth, moon, and meteorites is addressed.

Quantifying Engagement: Measuring Player Involvement in Human-Avatar Interactions

PubMed Central

Norris, Anne E.; Weger, Harry; Bullinger, Cory; Bowers, Alyssa

2014-01-01

This research investigated the merits of using an established system for rating behavioral cues of involvement in human dyadic interactions (i.e., face-to-face conversation) to measure involvement in human-avatar interactions. Gameplay audio-video and self-report data from a Feasibility Trial and Free Choice study of an effective peer resistance skill building simulation game (DRAMA-RAMA™) were used to evaluate reliability and validity of the rating system when applied to human-avatar interactions. The Free Choice study used a revised game prototype that was altered to be more engaging. Both studies involved girls enrolled in a public middle school in Central Florida that served a predominately Hispanic (greater than 80%), low-income student population. Audio-video data were coded by two raters, trained in the rating system. Self-report data were generated using measures of perceived realism, predictability and flow administered immediately after game play. Hypotheses for reliability and validity were supported: Reliability values mirrored those found in the human dyadic interaction literature. Validity was supported by factor analysis, significantly higher levels of involvement in Free Choice as compared to Feasibility Trial players, and correlations between involvement dimension sub scores and self-report measures. Results have implications for the science of both skill-training intervention research and game design. PMID:24748718

PACSAB: Coarse-Grained Force Field for the Study of Protein-Protein Interactions and Conformational Sampling in Multiprotein Systems.

PubMed

Emperador, Agustí; Sfriso, Pedro; Villarreal, Marcos Ariel; Gelpí, Josep Lluis; Orozco, Modesto

2015-12-08

Molecular dynamics simulations of proteins are usually performed on a single molecule, and coarse-grained protein models are calibrated using single-molecule simulations, therefore ignoring intermolecular interactions. We present here a new coarse-grained force field for the study of many protein systems. The force field, which is implemented in the context of the discrete molecular dynamics algorithm, is able to reproduce the properties of folded and unfolded proteins, in both isolation, complexed forming well-defined quaternary structures, or aggregated, thanks to its proper evaluation of protein-protein interactions. The accuracy and computational efficiency of the method makes it a universal tool for the study of the structure, dynamics, and association/dissociation of proteins.

Purely hydrodynamic ordering of rotating disks at a finite Reynolds number.

PubMed

Goto, Yusuke; Tanaka, Hajime

2015-01-28

Self-organization of moving objects in hydrodynamic environments has recently attracted considerable attention in connection to natural phenomena and living systems. However, the underlying physical mechanism is much less clear due to the intrinsically nonequilibrium nature, compared with self-organization of thermal systems. Hydrodynamic interactions are believed to play a crucial role in such phenomena. To elucidate the fundamental physical nature of many-body hydrodynamic interactions at a finite Reynolds number, here we study a system of co-rotating hard disks in a two-dimensional viscous fluid at zero temperature. Despite the absence of thermal noise, this system exhibits rich phase behaviours, including a fluid state with diffusive dynamics, a cluster state, a hexatic state, a glassy state, a plastic crystal state and phase demixing. We reveal that these behaviours are induced by the off-axis and many-body nature of nonlinear hydrodynamic interactions and the finite time required for propagating the interactions by momentum diffusion.

Hydrodynamic interaction between two vesicles in a linear shear flow: asymptotic study.

PubMed

Gires, P Y; Danker, G; Misbah, C

2012-07-01

Interactions between two vesicles in an imposed linear shear flow are studied theoretically, in the limit of almost spherical vesicles, with a large intervesicle distance, in a strong flow, with a large inner to outer viscosity ratio. This allows to derive a system of ordinary equations describing the dynamics of the two vesicles. We provide an analytic expression for the interaction law. We find that when the vesicles are in the same shear plane, the hydrodynamic interaction leads to a repulsion. When they are not, the interaction may turn into attraction instead. The interaction law is discussed and analyzed as a function of relevant parameters.

Membrane interaction of antimicrobial peptides using E. coli lipid extract as model bacterial cell membranes and SFG spectroscopy.

PubMed

Soblosky, Lauren; Ramamoorthy, Ayyalusamy; Chen, Zhan

2015-04-01

Supported lipid bilayers are used as a convenient model cell membrane system to study biologically important molecule-lipid interactions in situ. However, the lipid bilayer models are often simple and the acquired results with these models may not provide all pertinent information related to a real cell membrane. In this work, we use sum frequency generation (SFG) vibrational spectroscopy to study molecular-level interactions between the antimicrobial peptides (AMPs) MSI-594, ovispirin-1 G18, magainin 2 and a simple 1,2-dipalmitoyl-d62-sn-glycero-3-phosphoglycerol (dDPPG)/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) bilayer. We compared such interactions to those between the AMPs and a more complex dDPPG/Escherichia coli (E. coli) polar lipid extract bilayer. We show that to fully understand more complex aspects of peptide-bilayer interaction, such as interaction kinetics, a heterogeneous lipid composition is required, such as the E. coli polar lipid extract. The discrepancy in peptide-bilayer interaction is likely due in part to the difference in bilayer charge between the two systems since highly negative charged lipids can promote more favorable electrostatic interactions between the peptide and lipid bilayer. Results presented in this paper indicate that more complex model bilayers are needed to accurately analyze peptide-cell membrane interactions and demonstrates the importance of using an appropriate lipid composition to study AMP interaction properties. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Strontium isotope geochemistry of groundwater in the central part of the Dakota (Great Plains) aquifer, USA

USGS Publications Warehouse

Gosselin, D.C.; Harvey, F.E.; Frost, C.; Stotler, R.; Macfarlane, P.A.

2004-01-01

The Dakota aquifer of the central and eastern Great Plains of the United States is an important source of water for municipal supplies, irrigation and industrial use. Although the regional flow system can be characterized generally as east to northeasterly from the Rocky Mountains towards the Missouri River, locally the flow systems are hydrologically complex. This study uses Sr isotopic data from groundwater and leached aquifer samples to document the complex subsystems within the Dakota aquifer in Nebraska and Kansas. The interaction of groundwater with the geologic material through which it flows has created spatial patterns in the isotopic measurements that are related to: long-term water-rock interaction, during which varying degrees of isotopic equilibrium between water and rock has been achieved; and the alteration of NaCl fluids by water-rock interaction. Specifically, Sr isotopic data distinguish brines from Kansas and western Nebraska from those in eastern Nebraska: the former are interpreted to reflect interaction with Permian rocks, whereas the latter record interaction with Pennsylvanian rocks. The Sr isotopic composition of groundwater from other parts of Nebraska and Kansas are a function of the dynamic interaction between groundwater and unlithified sediments (e.g., glacial till and loess), followed by interaction with oxidized and unoxidized sediments within the Dakota Formation. This study illustrates the power of combining Sr chemistry with more conventional geochemical data to obtain a more complete understanding of groundwater flow systems within regional aquifer systems where extensive monitoring networks do not exist. ?? 2003 Elsevier Ltd. All rights reserved.

An Interactive Computer-Aided Instructional Strategy and Assessment Methods for System Identification and Adaptive Control Laboratory

ERIC Educational Resources Information Center

Özbek, Necdet Sinan; Eker, Ilyas

2015-01-01

This study describes a set of real-time interactive experiments that address system identification and model reference adaptive control (MRAC) techniques. In constructing laboratory experiments that contribute to efficient teaching, experimental design and instructional strategy are crucial, but a process for doing this has yet to be defined. This…

An Audience Response System May Influence Student Performance on Anatomy Examination Questions

ERIC Educational Resources Information Center

Hoyt, Amy; McNulty, John A.; Gruener, Gregory; Chandrasekhar, Arcot; Espiritu, Baltazar; Ensminger, David; Price, Ron, Jr.; Naheedy, Ross

2010-01-01

This study integrated an in-house audience response system (ARS) in the human anatomy course over two years to determine whether students performed better on high-stakes examinations following exposure to similar interactive questions in a large lecture format. Questions in an interactive ARS format were presented in lectures via PowerPoint…

The Interactivity Effect in Multimedia Learning

ERIC Educational Resources Information Center

Evans, Chris; Gibbons, Nicola J.

2007-01-01

The aim of this study was to determine whether the addition of interactivity to a computer-based learning package enhances the learning process. A sample of 33 (22 male and 11 female) undergraduates on a Business and Management degree used a multimedia system to learn about the operation of a bicycle pump. The system consisted of a labelled…

Perceptions of the Effectiveness of System Dynamics-Based Interactive Learning Environments: An Empirical Study

ERIC Educational Resources Information Center

Qudrat-Ullah, Hassan

2010-01-01

The use of simulations in general and of system dynamics simulation based interactive learning environments (SDILEs) in particular is well recognized as an effective way of improving users' decision making and learning in complex, dynamic tasks. However, the effectiveness of SDILEs in classrooms has rarely been evaluated. This article describes…

Distinct Brain Systems Underlie the Processing of Valence and Arousal of Affective Pictures

ERIC Educational Resources Information Center

Nielen, M. M. A.; Heslenfeld, D. J.; Heinen, K.; Van Strien, J. W.; Witter, M. P.; Jonker, C.; Veltman, D. J.

2009-01-01

Valence and arousal are thought to be the primary dimensions of human emotion. However, the degree to which valence and arousal interact in determining brain responses to emotional pictures is still elusive. This functional MRI study aimed to delineate neural systems responding to valence and arousal, and their interaction. We measured neural…

Ames interactive molecular model building system - A 3-D computer modelling system applied to the study of the origin of life

NASA Technical Reports Server (NTRS)

Coeckelenbergh, Y.; Macelroy, R. D.; Rein, R.

1978-01-01

The investigation of specific interactions among biological molecules must take into consideration the stereochemistry of the structures. Thus, models of the molecules are essential for describing the spatial organization of potentially interacting groups, and estimations of conformation are required for a description of spatial organization. Both the function of visualizing molecules, and that of estimating conformation through calculations of energy, are part of the molecular modeling system described in the present paper. The potential uses of the system in investigating some aspects of the origin of life rest on the assumption that translation of conformation from genetic elements to catalytic elements would have been required for the development of the first replicating systems subject to the process of biological evolution.

How (and why) the immune system makes us sleep

PubMed Central

Imeri, Luca; Opp, Mark R.

2010-01-01

Good sleep is necessary for physical and mental health. For example, sleep loss impairs immune function, and sleep is altered during infection. Immune signalling molecules are present in the healthy brain, where they interact with neurochemical systems to contribute to the regulation of normal sleep. Animal studies have shown that interactions between immune signalling molecules (such as the cytokine interleukin 1) and brain neurochemical systems (such as the serotonin system) are amplified during infection, indicating that these interactions might underlie the changes in sleep that occur during infection. Why should the immune system cause us to sleep differently when we are sick? We propose that the alterations in sleep architecture during infection are exquisitely tailored to support the generation of fever, which in turn imparts survival value. PMID:19209176

How (and why) the immune system makes us sleep.

PubMed

Imeri, Luca; Opp, Mark R

2009-03-01

Good sleep is necessary for physical and mental health. For example, sleep loss impairs immune function, and sleep is altered during infection. Immune signalling molecules are present in the healthy brain, where they interact with neurochemical systems to contribute to the regulation of normal sleep. Animal studies have shown that interactions between immune signalling molecules (such as the cytokine interleukin 1) and brain neurochemical systems (such as the serotonin system) are amplified during infection, indicating that these interactions might underlie the changes in sleep that occur during infection. Why should the immune system cause us to sleep differently when we are sick? We propose that the alterations in sleep architecture during infection are exquisitely tailored to support the generation of fever, which in turn imparts survival value.

Decoherence in quantum lossy systems: superoperator and matrix techniques

NASA Astrophysics Data System (ADS)

Yazdanpanah, Navid; Tavassoly, Mohammad Kazem; Moya-Cessa, Hector Manuel

2017-06-01

Due to the unavoidably dissipative interaction between quantum systems with their environments, the decoherence flows inevitably into the systems. Therefore, to achieve a better understanding on how decoherence affects on the damped systems, a fundamental investigation of master equation seems to be required. In this regard, finding out the missed information which has been lost due to irreversibly of the dissipative systems, is also of practical importance in quantum information science. Motivating by these facts, in this work we want to use superoperator and matrix techniques, by which we are able to illustrate two methods to obtain the explicit form of density operators corresponding to damped systems at arbitrary temperature T ≥ 0. To establish the potential abilities of the suggested methods, we apply them to deduce the density operator of some practical well-known quantum systems. Using the superoperator techniques, at first we obtain the density operator of a damped system which includes a qubit interacting with a single-mode quantized field within an optical cavity. As the second system, we study the decoherence of a quantized field within an optical damped cavity. We also use our proposed matrix method to study the decoherence of a system which includes two qubits in the interaction with each other via dipole-dipole interaction and at the same time with a quantized field in a lossy cavity. The influences of dissipation on the decoherence of dynamical properties of these systems are also numerically investigated. At last, the advantages of the proposed superoperator techniques in comparison with matrix method are explained.

Effect of three-body interactions on the zero-temperature equation of state of HCP solid 4He

NASA Astrophysics Data System (ADS)

Barnes, Ashleigh L.; Hinde, Robert J.

2017-03-01

Previous studies have pointed to the importance of three-body interactions in high density 4He solids. However the computational cost often makes it unfeasible to incorporate these interactions into the simulation of large systems. We report the implementation and evaluation of a computationally efficient perturbative treatment of three-body interactions in hexagonal close packed solid 4He utilizing the recently developed nonadditive three-body potential of Cencek et al. This study represents the first application of the Cencek three-body potential to condensed phase 4He systems. Ground state energies from quantum Monte Carlo simulations, with either fully incorporated or perturbatively treated three-body interactions, are calculated in systems with molar volumes ranging from 21.3 cm3/mol down to 2.5 cm3/mol. These energies are used to derive the zero-temperature equation of state for comparison against existing experimental and theoretical data. The equations of state derived from both perturbative and fully incorporated three-body interactions are found to be in very good agreement with one another, and reproduce the experimental pressure-volume data with significantly better accuracy than is obtained when only two-body interactions are considered. At molar volumes below approximately 4.0 cm3/mol, neither two-body nor three-body equations of state are able to accurately reproduce the experimental pressure-volume data, suggesting that below this molar volume four-body and higher many-body interactions are becoming important.

The immune response against Candida spp. and Sporothrix schenckii.

PubMed

Martínez-Álvarez, José A; Pérez-García, Luis A; Flores-Carreón, Arturo; Mora-Montes, Héctor M

2014-01-01

Candida albicans is the main causative agent of systemic candidiasis, a condition with high mortality rates. The study of the interaction between C. albicans and immune system components has been thoroughly studied and nowadays there is a model for the anti-C. albicans immune response; however, little is known about the sensing of other pathogenic species of the Candida genus. Sporothrix schenckii is the causative agent of sporotrichosis, a subcutaneous mycosis, and thus far there is limited information about its interaction with the immune system. In this paper, we review the most recent information about the immune sensing of species from genus Candida and S. schenckii. Thoroughly searches in scientific journal databases were performed, looking for papers addressing either Candida- or Sporothrix-immune system interactions. There is a significant advance in the knowledge of non-C. albicans species of Candida and Sporothrix immune sensing; however, there are still relevant points to address, such as the specific contribution of pathogen-associated molecular patterns (PAMPs) for sensing by different immune cells and the immune receptors involved in such interactions. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012). Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Positioning true coincidences that undergo inter-and intra-crystal scatter for a sub-mm resolution cadmium zinc telluride-based PET system

NASA Astrophysics Data System (ADS)

Abbaszadeh, Shiva; Chinn, Garry; Levin, Craig S.

2018-01-01

The kinematics of Compton scatter can be used to estimate the interaction sequence of inter-crystal scatter interactions in 3D position-sensitive cadmium zinc telluride (CZT) detectors. However, in the case of intra-crystal scatter in a ‘cross-strip’ CZT detector slab, multiple anode and cathode strips may be triggered, creating position ambiguity due to uncertainty in possible combinations of anode-cathode pairings. As a consequence, methods such as energy-weighted centroid are not applicable to position the interactions. In practice, since the event position is uncertain, these intra-crystal scatters events are discarded. In this work, we studied using Compton kinematics and a ‘direction difference angle’ to provide a method to correctly identify the anode-cathode pair corresponding to the first interaction position in an intra-crystal scatter event. GATE simulation studies of a NEMA NU4 image quality phantom in a small animal positron emission tomography under development composed of 192, 40~mm×40~mm×5 mm CZT crystals shows that 47% of total numbers of multiple-interaction photon events (MIPEs) are intra-crystal scatter with a 100 keV lower energy threshold per interaction. The sensitivity of the system increases from 0.6 to 4.10 (using 10 keV as system lower energy threshold) by including rather than discarding inter- and intra-crystal scatter. The contrast-to-noise ratio (CNR) also increases from 5.81+/-0.3 to 12.53+/-0.37 . It was shown that a higher energy threshold limits the capability of the system to detect MIPEs and reduces CNR. Results indicate a sensitivity increase (4.1 to 5.88) when raising the lower energy threshold (10 keV to 100 keV) for the case of only two-interaction events. In order to detect MIPEs accurately, a low noise system capable of a low energy threshold (10 keV) per interaction is desired.

I-DIRT, a general method for distinguishing between specific and nonspecific protein interactions.

PubMed

Tackett, Alan J; DeGrasse, Jeffrey A; Sekedat, Matthew D; Oeffinger, Marlene; Rout, Michael P; Chait, Brian T

2005-01-01

Isolation of protein complexes via affinity-tagged proteins provides a powerful tool for studying biological systems, but the technique is often compromised by co-enrichment of nonspecifically interacting proteins. We describe a new technique (I-DIRT) that distinguishes contaminants from bona fide interactors in immunopurifications, overcoming this most challenging problem in defining protein complexes. I-DIRT will be of broad value for studying protein complexes in biological systems that can be metabolically labeled.

Quasi-static analysis of elastic behavior for some systems having higher fracture densities.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berryman, J.G.; Aydin, A.

2009-10-15

Elastic behavior of geomechanical systems with interacting (but not intersecting) fractures is treated using generalizations of the Backus and the Schoenberg-Muir methods for analyzing layered systems whose layers are intrinsically anisotropic due to locally aligned fractures. By permitting the axis of symmetry of the locally anisotropic compliance matrix for individual layers to differ from that of the layering direction, we derive analytical formulas for interacting fractured regions with arbitrary orientations to each other. This procedure provides a systematic tool for studying how contiguous, but not yet intersecting, fractured domains interact, and provides a direct (though approximate) means of predicting whenmore » and how such interactions lead to more dramatic weakening effects and ultimately to failure of these complicated systems. The method permits decomposition of the system elastic behavior into specific eigenmodes that can all be analyzed, and provides a better understanding about which of these specific modes are expected to be most important to the evolving failure process.« less

Floquet prethermalization and regimes of heating in a periodically driven, interacting quantum system

NASA Astrophysics Data System (ADS)

Weidinger, Simon A.; Knap, Michael

2017-04-01

We study the regimes of heating in the periodically driven O(N)-model, which is a well established model for interacting quantum many-body systems. By computing the absorbed energy with a non-equilibrium Keldysh Green’s function approach, we establish three dynamical regimes: at short times a single-particle dominated regime, at intermediate times a stable Floquet prethermal regime in which the system ceases to absorb, and at parametrically late times a thermalizing regime. Our simulations suggest that in the thermalizing regime the absorbed energy grows algebraically in time with an exponent that approaches the universal value of 1/2, and is thus significantly slower than linear Joule heating. Our results demonstrate the parametric stability of prethermal states in a many-body system driven at frequencies that are comparable to its microscopic scales. This paves the way for realizing exotic quantum phases, such as time crystals or interacting topological phases, in the prethermal regime of interacting Floquet systems.

Plasmon-modulated bistable four-wave mixing signals from a metal nanoparticle-monolayer MoS2 nanoresonator hybrid system.

PubMed

Li, Jian-Bo; Tan, Xiao-Long; Ma, Jin-Hong; Xu, Si-Qin; Kuang, Zhi-Wei; Liang, Shan; Xiao, Si; He, Meng-Dong; Kim, Nam-Chol; Luo, Jian-Hua; Chen, Li-Qun

2018-06-22

We present a study for the impact of exciton-phonon and exciton-plasmon interactions on bistable four-wave mixing (FWM) signals in a metal nanoparticle (MNP)-monolayer MoS 2 nanoresonator hybrid system. Via tracing the FWM response we predict that, depending on the excitation conditions and the system parameters, such a system exhibits 'U-shaped' bistable FWM signals. We also map out bistability phase diagrams within the system's parameter space. Especially, we show that compared with the exciton-phonon interaction, a strong exciton-plasmon interaction plays a dominant role in the generation of optical bistability, and the bistable region will be greatly broadened by shortening the distance between the MNP and the monolayer MoS 2 nanoresonator. In the weak exciton-plasmon coupling regime, the impact of exciton-phonon interaction on optical bistability will become obvious. The scheme proposed may be used for building optical switches and logic-gate devices for optical computing and quantum information processing.

Random catalytic reaction networks

NASA Astrophysics Data System (ADS)

Stadler, Peter F.; Fontana, Walter; Miller, John H.

1993-03-01

We study networks that are a generalization of replicator (or Lotka-Volterra) equations. They model the dynamics of a population of object types whose binary interactions determine the specific type of interaction product. Such a system always reduces its dimension to a subset that contains production pathways for all of its members. The network equation can be rewritten at a level of collectives in terms of two basic interaction patterns: replicator sets and cyclic transformation pathways among sets. Although the system contains well-known cases that exhibit very complicated dynamics, the generic behavior of randomly generated systems is found (numerically) to be extremely robust: convergence to a globally stable rest point. It is easy to tailor networks that display replicator interactions where the replicators are entire self-sustaining subsystems, rather than structureless units. A numerical scan of random systems highlights the special properties of elementary replicators: they reduce the effective interconnectedness of the system, resulting in enhanced competition, and strong correlations between the concentrations.

Interactions between selected bile salts and Triton X-100 or sodium lauryl ether sulfate.

PubMed

Cirin, Dejan M; Poša, Mihalj M; Krstonošić, Veljko S

2011-12-29

In order to develop colloidal drug carriers with desired properties, it is important to determine physico-chemical characteristics of these systems. Bile salt mixed micelles are extensively studied as novel drug delivery systems. The objective of the present investigation is to develop and characterize mixed micelles of nonionic (Triton X-100) or anionic (sodium lauryl ether sulfate) surfactant having oxyethylene groups in the polar head and following bile salts: cholate, deoxycholate and 7-oxodeoxycholate. The micellization behaviour of binary anionic-nonionic and anionic-anionic surfactant mixtures was investigated by conductivity and surface tension measurements. The results of the study have been analyzed using Clint's, Rubingh's, and Motomura's theories for mixed binary systems. The negative values of the interaction parameter indicate synergism between micelle building units. It was noticed that Triton X-100 and sodium lauryl ether sulfate generate the weakest synergistic interactions with sodium deoxycholate, while 7-oxodeoxycholate creates the strongest attractive interaction with investigated co-surfactants. It was concluded that increased synergistic interactions can be attributed to the larger number of hydrophilic groups at α side of the bile salts. Additionally, 7-oxo group of 7-oxodeoxycholate enhance attractive interactions with selected co-surfactants more than 7-hydroxyl group of sodium cholate.

Interactions between selected bile salts and Triton X-100 or sodium lauryl ether sulfate

PubMed Central

2011-01-01

Background In order to develop colloidal drug carriers with desired properties, it is important to determine physico-chemical characteristics of these systems. Bile salt mixed micelles are extensively studied as novel drug delivery systems. The objective of the present investigation is to develop and characterize mixed micelles of nonionic (Triton X-100) or anionic (sodium lauryl ether sulfate) surfactant having oxyethylene groups in the polar head and following bile salts: cholate, deoxycholate and 7-oxodeoxycholate. Results The micellization behaviour of binary anionic-nonionic and anionic-anionic surfactant mixtures was investigated by conductivity and surface tension measurements. The results of the study have been analyzed using Clint's, Rubingh's, and Motomura's theories for mixed binary systems. The negative values of the interaction parameter indicate synergism between micelle building units. It was noticed that Triton X-100 and sodium lauryl ether sulfate generate the weakest synergistic interactions with sodium deoxycholate, while 7-oxodeoxycholate creates the strongest attractive interaction with investigated co-surfactants. Conclusion It was concluded that increased synergistic interactions can be attributed to the larger number of hydrophilic groups at α side of the bile salts. Additionally, 7-oxo group of 7-oxodeoxycholate enhance attractive interactions with selected co-surfactants more than 7-hydroxyl group of sodium cholate. PMID:22206681

Quantum chaos in the Heisenberg spin chain: The effect of Dzyaloshinskii-Moriya interaction.

PubMed

Vahedi, J; Ashouri, A; Mahdavifar, S

2016-10-01

Using one-dimensional spin-1/2 systems as prototypes of quantum many-body systems, we study the emergence of quantum chaos. The main purpose of this work is to answer the following question: how the spin-orbit interaction, as a pure quantum interaction, may lead to the onset of quantum chaos? We consider the three integrable spin-1/2 systems: the Ising, the XX, and the XXZ limits and analyze whether quantum chaos develops or not after the addition of the Dzyaloshinskii-Moriya interaction. We find that depending on the strength of the anisotropy parameter, the answer is positive for the XXZ and Ising models, whereas no such evidence is observed for the XX model. We also discuss the relationship between quantum chaos and thermalization.

Interplay of interaction and disorder in the steady state of an open quantum system

NASA Astrophysics Data System (ADS)

Xu, Xiansong; Guo, Chu; Poletti, Dario

2018-04-01

Many types of dissipative processes can be found in nature or be engineered, and their interplay with a system can give rise to interesting phases of matter. Here we study the interplay among interaction, tunneling, and disorder in the steady state of a spin chain coupled to a tailored bath. We consider a dissipation which, in contrast to disorder, tends to generate a homogeneously polarized steady state. We find that the steady state can be highly sensitive even to weak disorder. We also establish that, in the presence of such dissipation, even in the absence of interaction, a finite amount of disorder is needed for localization. Last, we show that for strong disorder the system reveals signatures of localization both in the weakly and strong interacting regimes.

Challenges of Developing Communicative Interaction in Individuals with Congenital Profound Intellectual and Multiple Disabilities

ERIC Educational Resources Information Center

Blain-Moraes, Stefanie; Chau, Tom

2012-01-01

Background: Physiological responses have been used in individuals with acquired disability to enable communicative interaction without motor movement. This study explored four autonomic nervous system (ANS) signals--electrodermal activity, skin temperature, cardiac patterns and respiratory patterns--to enable interaction with individuals born with…

Modernization: A Case Study of the Interaction of Setting, Custom, and Ideology.

ERIC Educational Resources Information Center

Frankel, Daniel G.; Roer-Bornstein, Dorit

An investigation was conducted to better understand the interaction between physical and social settings, culturally based customs for parenting, and the ideology of caretakers in two Israeli cultures undergoing modernization. Yemenite and Kurdish parenting systems were examined by observing mother/infant interactions in unstructured naturalistic…

Interaction Patterns in Couples with a Depressed Partner.

ERIC Educational Resources Information Center

Hautzinger, Martin

Recently, research has been conducted using an interactional understanding of depression, which views depression as a disorder exacerbated by a pathogenic social system. The interaction between intimate social partners seems especially relevant. Couples (N=26) participated in a study of depressed out-patients and their spouses and a matched…

Effect of Liquid Crystalline Systems Containing Antimicrobial Compounds on Infectious Skin Bacteria.

PubMed

Souza, Carla; Watanabe, Evandro; Aires, Carolina Patrícia; Lara, Marilisa Guimarães

2017-08-01

This study aimed (i) to prepare liquid crystalline systems (LCS) of glyceryl monooleate (GMO) and water containing antibacterial compounds and (ii) to evaluate their potential as drug delivery systems for topical treatment of bacterial infections. Therefore, LCS containing CPC (cetylpyridinium chloride) (LCS/CPC) and PHMB (poly(hexamethylene biguanide) hydrochloride) (LCS/PHMB) were prepared and the liquid crystalline phases were identified by polarizing light microscopy 24 h and 7 days after preparation. The in vitro drug release profile and in vitro antibacterial activity of the systems were assessed using the double layer agar diffusion method against Staphylococcus aureus, methicillin-resistant S. aureus, Staphylococcus epidermidis, Escherichia coli, and Enterococcus faecalis. The interaction between GMO and the drugs was evaluated by a drug absorption study. Stable liquid crystalline systems containing CPC and PHMB were obtained. LCS/PHMB decreased the PHMB release rate and exerted strong antibacterial activity against all the investigated bacteria. In contrast, CPC interacted with GMO so strongly that it became attached to the system; the amount released was not sufficient to exert antibacterial activity. Therefore, the studied liquid crystalline systems were suitable to deliver PHMB, but not CPC. Accordingly, it was demonstrated that GMO interacts with each drug differently, which may interfere in the final efficiency of GMO/water LCS.

AOIPS water resources data management system

NASA Technical Reports Server (NTRS)

Merritt, E. S.; Shotwell, R. L.; Place, M. C.; Belknap, N. J.

1976-01-01

A geocoded data management system applicable for hydrological applications was designed to demonstrate the utility of the Atmospheric and Oceanographic Information Processing System (AOIPS) for hydrological applications. Within that context, the geocoded hydrology data management system was designed to take advantage of the interactive capability of the AOIPS hardware. Portions of the Water Resource Data Management System which best demonstrate the interactive nature of the hydrology data management system were implemented on the AOIPS. A hydrological case study was prepared using all data supplied for the Bear River watershed located in northwest Utah, southeast Idaho, and western Wyoming.

Degeneracy-Driven Self-Structuring Dynamics in Selective Repertoires

PubMed Central

Atamas, Sergei P.; Bell, Jonathan

2013-01-01

Numerous biological interactions, such as interactions between T cell receptors or antibodies with antigens, interactions between enzymes and substrates, or interactions between predators and prey are often not strictly specific. In such less specific, or “sloppy,” systems, referred to here as degenerate systems, a given unit of a diverse resource (antigens, enzymatic substrates, prey) is at risk of being recognized and consumed by multiple consumers (lymphocytes, enzymes, predators). In this study, we model generalized degenerate consumer-resource systems of Lotka–Volterra and Verhulst types. In the degenerate systems of Lotka–Volterra, there is a continuum of types of consumer and resource based on variation of a single trait (characteristic, or preference). The consumers experience competition for a continuum of resource types. This non-local interaction system is modeled with partial differential-integral equations and shows spontaneous self-structuring of the consumer population that depends on the degree of interaction degeneracy between resource and consumer, but does not mirror the distribution of resource. We also show that the classical Verhulst (i.e. logistic) single population model can be generalized to a degenerate model, which shows qualitative behavior similar to that in the degenerate Lotka–Volterra model. These results provide better insight into the dynamics of selective systems in biology, suggesting that adaptation of degenerate repertoires is not a simple “mirroring” of the environment by the “fittest” elements of population. PMID:19337776

Degeneracy-driven self-structuring dynamics in selective repertoires.

PubMed

Atamas, Sergei P; Bell, Jonathan

2009-08-01

Numerous biological interactions, such as interactions between T cell receptors or antibodies with antigens, interactions between enzymes and substrates, or interactions between predators and prey are often not strictly specific. In such less specific, or "sloppy," systems, referred to here as degenerate systems, a given unit of a diverse resource (antigens, enzymatic substrates, prey) is at risk of being recognized and consumed by multiple consumers (lymphocytes, enzymes, predators). In this study, we model generalized degenerate consumer-resource systems of Lotka-Volterra and Verhulst types. In the degenerate systems of Lotka-Volterra, there is a continuum of types of consumer and resource based on variation of a single trait (characteristic, or preference). The consumers experience competition for a continuum of resource types. This non-local interaction system is modeled with partial differential-integral equations and shows spontaneous self-structuring of the consumer population that depends on the degree of interaction degeneracy between resource and consumer, but does not mirror the distribution of resource. We also show that the classical Verhulst (i.e. logistic) single population model can be generalized to a degenerate model, which shows qualitative behavior similar to that in the degenerate Lotka-Volterra model. These results provide better insight into the dynamics of selective systems in biology, suggesting that adaptation of degenerate repertoires is not a simple "mirroring" of the environment by the "fittest" elements of population.

In vitro Method to Observe E-selectin-mediated Interactions Between Prostate Circulating Tumor Cells Derived From Patients and Human Endothelial Cells

PubMed Central

Gakhar, Gunjan; Bander, Neil H.; Nanus, David M.

2014-01-01

Metastasis is a process in which tumor cells shed from the primary tumor intravasate blood vascular and lymphatic system, thereby, gaining access to extravasate and form a secondary niche. The extravasation of tumor cells from the blood vascular system can be studied using endothelial cells (ECs) and tumor cells obtained from different cell lines. Initial studies were conducted using static conditions but it has been well documented that ECs behave differently under physiological flow conditions. Therefore, different flow chamber assemblies are currently being used to studying cancer cell interactions with ECs. Current flow chamber assemblies offer reproducible results using either different cell lines or fluid at different shear stress conditions. However, to observe and study interactions with rare cells such as circulating tumor cells (CTCs), certain changes are required to be made to the conventional flow chamber assembly. CTCs are a rare cell population among millions of blood cells. Consequently, it is difficult to obtain a pure population of CTCs. Contamination of CTCs with different types of cells normally found in the circulation is inevitable using present enrichment or depletion techniques. In the present report, we describe a unique method to fluorescently label circulating prostate cancer cells and study their interactions with ECs in a self-assembled flow chamber system. This technique can be further applied to observe interactions between prostate CTCs and any protein of interest. PMID:24894373

Pairwise Maximum Entropy Models for Studying Large Biological Systems: When They Can Work and When They Can't

PubMed Central

Roudi, Yasser; Nirenberg, Sheila; Latham, Peter E.

2009-01-01

One of the most critical problems we face in the study of biological systems is building accurate statistical descriptions of them. This problem has been particularly challenging because biological systems typically contain large numbers of interacting elements, which precludes the use of standard brute force approaches. Recently, though, several groups have reported that there may be an alternate strategy. The reports show that reliable statistical models can be built without knowledge of all the interactions in a system; instead, pairwise interactions can suffice. These findings, however, are based on the analysis of small subsystems. Here, we ask whether the observations will generalize to systems of realistic size, that is, whether pairwise models will provide reliable descriptions of true biological systems. Our results show that, in most cases, they will not. The reason is that there is a crossover in the predictive power of pairwise models: If the size of the subsystem is below the crossover point, then the results have no predictive power for large systems. If the size is above the crossover point, then the results may have predictive power. This work thus provides a general framework for determining the extent to which pairwise models can be used to predict the behavior of large biological systems. Applied to neural data, the size of most systems studied so far is below the crossover point. PMID:19424487

Many-body physics using cold atoms

NASA Astrophysics Data System (ADS)

Sundar, Bhuvanesh

Advances in experiments on dilute ultracold atomic gases have given us access to highly tunable quantum systems. In particular, there have been substantial improvements in achieving different kinds of interaction between atoms. As a result, utracold atomic gases oer an ideal platform to simulate many-body phenomena in condensed matter physics, and engineer other novel phenomena that are a result of the exotic interactions produced between atoms. In this dissertation, I present a series of studies that explore the physics of dilute ultracold atomic gases in different settings. In each setting, I explore a different form of the inter-particle interaction. Motivated by experiments which induce artificial spin-orbit coupling for cold fermions, I explore this system in my first project. In this project, I propose a method to perform universal quantum computation using the excitations of interacting spin-orbit coupled fermions, in which effective p-wave interactions lead to the formation of a topological superfluid. Motivated by experiments which explore the physics of exotic interactions between atoms trapped inside optical cavities, I explore this system in a second project. I calculate the phase diagram of lattice bosons trapped in an optical cavity, where the cavity modes mediates effective global range checkerboard interactions between the atoms. I compare this phase diagram with one that was recently measured experimentally. In two other projects, I explore quantum simulation of condensed matter phenomena due to spin-dependent interactions between particles. I propose a method to produce tunable spin-dependent interactions between atoms, using an optical Feshbach resonance. In one project, I use these spin-dependent interactions in an ultracold Bose-Fermi system, and propose a method to produce the Kondo model. I propose an experiment to directly observe the Kondo effect in this system. In another project, I propose using lattice bosons with a large hyperfine spin, which have Feshbach-induced spin-dependent interactions, to produce a quantum dimer model. I propose an experiment to detect the ground state in this system. In a final project, I develop tools to simulate the dynamics of fermionic superfluids in which fermions interact via a short-range interaction.

Radiative energy transfer in molecular gases

NASA Technical Reports Server (NTRS)

Tiwari, Surendra N.

1992-01-01

Basic formulations, analyses, and numerical procedures are presented to study radiative interactions in gray as well as nongray gases under different physical and flow conditions. After preliminary fluid-dynamical considerations, essential governing equations for radiative transport are presented that are applicable under local and nonlocal thermodynamic equilibrium conditions. Auxiliary relations for relaxation times and spectral absorption models are also provided. For specific applications, several simple gaseous systems are analyzed. The first system considered consists of a gas bounded by two parallel plates having the same temperature. Within the gas there is a uniform heat source per unit volume. For this system, both vibrational nonequilibrium effects and radiation conduction interactions are studied. The second system consists of fully developed laminar flow and heat transfer in a parallel plate duct under the boundary condition of a uniform surface heat flux. For this system, effects of gray surface emittance are studied. With the single exception of a circular geometry, the third system is considered identical to the second system. Here, the influence of nongray walls is also studied.

The interactive contents authoring system for terrestrial digital multimedia broadcasting

NASA Astrophysics Data System (ADS)

Cheong, Won-Sik; Ahn, Sangwoo; Cha, Jihun; Moon, Kyung Ae

2007-02-01

This paper introduces an interactive contents authoring system which can easily and conveniently produce interactive contents for the Terrestrial Digital Multimedia Broadcasting (T-DMB). For interactive broadcasting service, T-DMB adopted MPEG-4 Systems technology. In order to the interactive service becomes flourishing on the market, various types of interactive contents should be well provided prior to the service. In MPEG-4 Systems specification, broadcasting contents are described by the combination of a large number of nodes, routes and descriptors. In order to provide interactive data services through the T-DMB network, it is essential to have an interactive contents authoring system which allows contents authors to compose interactive contents easily and conveniently even if they lack any background on MPEG-4 Systems technology. The introduced authoring system provides powerful graphical user interface and produces interactive broadcasting contents in the forms of binary and textual format. Therefore, the interactive contents authoring system presented in this paper would vastly contribute to the flourishing interactive service.

First-order metal-insulator transitions in the extended Hubbard model due to self-consistent screening of the effective interaction

NASA Astrophysics Data System (ADS)

Schüler, M.; van Loon, E. G. C. P.; Katsnelson, M. I.; Wehling, T. O.

2018-04-01

While the Hubbard model is the standard model to study Mott metal-insulator transitions, it is still unclear to what extent it can describe metal-insulator transitions in real solids, where nonlocal Coulomb interactions are always present. By using a variational principle, we clarify this issue for short- and long-range nonlocal Coulomb interactions for half-filled systems on bipartite lattices. We find that repulsive nonlocal interactions generally stabilize the Fermi-liquid regime. The metal-insulator phase boundary is shifted to larger interaction strengths to leading order linearly with nonlocal interactions. Importantly, nonlocal interactions can raise the order of the metal-insulator transition. We present a detailed analysis of how the dimension and geometry of the lattice as well as the temperature determine the critical nonlocal interaction leading to a first-order transition: for systems in more than two dimensions with nonzero density of states at the Fermi energy the critical nonlocal interaction is arbitrarily small; otherwise, it is finite.

Information Interaction Study for DER and DMS Interoperability

NASA Astrophysics Data System (ADS)

Liu, Haitao; Lu, Yiming; Lv, Guangxian; Liu, Peng; Chen, Yu; Zhang, Xinhui

The Common Information Model (CIM) is an abstract data model that can be used to represent the major objects in Distribution Management System (DMS) applications. Because the Common Information Model (CIM) doesn't modeling the Distributed Energy Resources (DERs), it can't meet the requirements of DER operation and management for Distribution Management System (DMS) advanced applications. Modeling of DER were studied based on a system point of view, the article initially proposed a CIM extended information model. By analysis the basic structure of the message interaction between DMS and DER, a bidirectional messaging mapping method based on data exchange was proposed.

Synchronization and Causality Across Time-scales: Complex Dynamics and Extremes in El Niño/Southern Oscillation

NASA Astrophysics Data System (ADS)

Jajcay, N.; Kravtsov, S.; Tsonis, A.; Palus, M.

2017-12-01

A better understanding of dynamics in complex systems, such as the Earth's climate is one of the key challenges for contemporary science and society. A large amount of experimental data requires new mathematical and computational approaches. Natural complex systems vary on many temporal and spatial scales, often exhibiting recurring patterns and quasi-oscillatory phenomena. The statistical inference of causal interactions and synchronization between dynamical phenomena evolving on different temporal scales is of vital importance for better understanding of underlying mechanisms and a key for modeling and prediction of such systems. This study introduces and applies information theory diagnostics to phase and amplitude time series of different wavelet components of the observed data that characterizes El Niño. A suite of significant interactions between processes operating on different time scales was detected, and intermittent synchronization among different time scales has been associated with the extreme El Niño events. The mechanisms of these nonlinear interactions were further studied in conceptual low-order and state-of-the-art dynamical, as well as statistical climate models. Observed and simulated interactions exhibit substantial discrepancies, whose understanding may be the key to an improved prediction. Moreover, the statistical framework which we apply here is suitable for direct usage of inferring cross-scale interactions in nonlinear time series from complex systems such as the terrestrial magnetosphere, solar-terrestrial interactions, seismic activity or even human brain dynamics.

Magnetism of a Co monolayer on Pt(111) capped by overlayers of 5 d elements: A spin-model study

NASA Astrophysics Data System (ADS)

Simon, E.; Rózsa, L.; Palotás, K.; Szunyogh, L.

2018-04-01

Using first-principles calculations, we study the magnetic properties of a Co monolayer on a Pt(111) surface with a capping monolayer of selected 5 d elements (Re, Os, Ir, Pt, and Au). First we determine the tensorial exchange interactions and magnetic anisotropies characterizing the Co monolayer for all considered systems. We find a close relationship between the magnetic moment of the Co atoms and the nearest-neighbor isotropic exchange interaction, which is attributed to the electronic hybridization between the Co and the capping layers, in the spirit of the Stoner picture of ferromagnetism. The Dzyaloshinskii-Moriya interaction is decreased for all overlayers compared to the uncapped Co/Pt(111) system, while even the sign of the Dzyaloshinskii-Moriya interaction changes in the case of the Ir overlayer. We conclude that the variation of the Dzyaloshinskii-Moriya interaction is well correlated with the change of the magnetic anisotropy energy and of the orbital moment anisotropy. The unique influence of the Ir overlayer on the Dzyaloshinskii-Moriya interaction is traced by scaling the strength of the spin-orbit coupling of the Ir atoms in Ir/Co/Pt(111) and by changing the Ir concentration in the Au1 -xIrx /Co/Pt(111) system. Our spin dynamics simulations indicate that the magnetic ground state of Re/Co/Pt(111) thin film is a spin spiral with a tilted normal vector, while the other systems are ferromagnetic.

Occupational stress in human computer interaction.

PubMed

Smith, M J; Conway, F T; Karsh, B T

1999-04-01

There have been a variety of research approaches that have examined the stress issues related to human computer interaction including laboratory studies, cross-sectional surveys, longitudinal case studies and intervention studies. A critical review of these studies indicates that there are important physiological, biochemical, somatic and psychological indicators of stress that are related to work activities where human computer interaction occurs. Many of the stressors of human computer interaction at work are similar to those stressors that have historically been observed in other automated jobs. These include high workload, high work pressure, diminished job control, inadequate employee training to use new technology, monotonous tasks, por supervisory relations, and fear for job security. New stressors have emerged that can be tied primarily to human computer interaction. These include technology breakdowns, technology slowdowns, and electronic performance monitoring. The effects of the stress of human computer interaction in the workplace are increased physiological arousal; somatic complaints, especially of the musculoskeletal system; mood disturbances, particularly anxiety, fear and anger; and diminished quality of working life, such as reduced job satisfaction. Interventions to reduce the stress of computer technology have included improved technology implementation approaches and increased employee participation in implementation. Recommendations for ways to reduce the stress of human computer interaction at work are presented. These include proper ergonomic conditions, increased organizational support, improved job content, proper workload to decrease work pressure, and enhanced opportunities for social support. A model approach to the design of human computer interaction at work that focuses on the system "balance" is proposed.

Neutron Measurements and the Weak Nucleon-Nucleon Interaction

PubMed Central

Snow, W. M.

2005-01-01

The weak interaction between nucleons remains one of the most poorly-understood sectors of the Standard Model. A quantitative description of this interaction is needed to understand weak interaction phenomena in atomic, nuclear, and hadronic systems. This paper summarizes briefly what is known about the weak nucleon-nucleon interaction, tries to place this phenomenon in the context of other studies of the weak and strong interactions, and outlines a set of measurements involving low energy neutrons which can lead to significant experimental progress. PMID:27308120

Evaluation of a Digital Companion for Older Adults with Mild Cognitive Impairment.

PubMed

Demiris, George; Thompson, Hilaire J; Lazar, Amanda; Lin, Shih-Yin

2016-01-01

Study Objective: The purpose of this study was to examine the feasibility of a digital companion system used by older adults with mild cognitive impairment (MCI). We utilized a commercially available system that is comprehensive in its functionalities (including conversation ability, use of pictures and other media, and reminders) to explore the system's impact on older adults ' social interactions, anxiety, depressive symptoms, and acceptance of the system. Study Design: We conducted a three-month mixed methods evaluation study of the digital companion. Results: Ten female community-dwelling older adults (average age 78.3 years) participated in the study. Overall, participants utilized the tool regularly and appreciated its presence and their interactions. Participants scored higher at the end of the study in cognition and social support scales, and lower in presence of depressive symptoms. Conclusion: Findings indicate the feasibility of a digital companion for people with MCI and inform the need for additional research.

Atmospheric and oceanographic research review, 1979

NASA Technical Reports Server (NTRS)

1980-01-01

Papers generated by atmospheric, oceanographic, and climatological research performed during 1979 at the Goddard Laboratory for Atmospheric Sciences are presented. The GARP/global weather research is aimed at developing techniques for the utilization and analysis of the FGGE data sets. Observing system studies were aimed at developing a GLAS TIROS N sounding retrieval system and preparing for the joint NOAA/NASA AMTS simulation study. The climate research objective is to support the development and effective utilization of space acquired data systems by developing the GLAS GCM for short range climate predictions, studies of the sensitivity of climate to boundary conditions, and predictability studies. Ocean/air interaction studies concentrated on the development of models for the prediction of upper ocean currents, temperatures, sea state, mixed layer depths, and upwelling zones, and on studies of the interactions of the atmospheric and oceanic circulation systems on time scales of a month or more.

Entanglement entropy in a one-dimensional disordered interacting system: the role of localization.

PubMed

Berkovits, Richard

2012-04-27

The properties of the entanglement entropy (EE) in one-dimensional disordered interacting systems are studied. Anderson localization leaves a clear signature on the average EE, as it saturates on the length scale exceeding the localization length. This is verified by numerically calculating the EE for an ensemble of disordered realizations using the density matrix renormalization group method. A heuristic expression describing the dependence of the EE on the localization length, which takes into account finite-size effects, is proposed. This is used to extract the localization length as a function of the interaction strength. The localization length dependence on the interaction fits nicely with the expectations.

Random matrix ensembles for many-body quantum systems

NASA Astrophysics Data System (ADS)

Vyas, Manan; Seligman, Thomas H.

2018-04-01

Classical random matrix ensembles were originally introduced in physics to approximate quantum many-particle nuclear interactions. However, there exists a plethora of quantum systems whose dynamics is explained in terms of few-particle (predom-inantly two-particle) interactions. The random matrix models incorporating the few-particle nature of interactions are known as embedded random matrix ensembles. In the present paper, we provide a brief overview of these two ensembles and illustrate how the embedded ensembles can be successfully used to study decoherence of a qubit interacting with an environment, both for fermionic and bosonic embedded ensembles. Numerical calculations show the dependence of decoherence on the nature of the environment.

Two-soliton interaction as an elementary act of soliton turbulence in integrable systems

NASA Astrophysics Data System (ADS)

Pelinovsky, E. N.; Shurgalina, E. G.; Sergeeva, A. V.; Talipova, T. G.; El, G. A.; Grimshaw, R. H. J.

2013-01-01

Two-soliton interactions play a definitive role in the formation of the structure of soliton turbulence in integrable systems. To quantify the contribution of these interactions to the dynamical and statistical characteristics of the nonlinear wave field of soliton turbulence we study properties of the spatial moments of the two-soliton solution of the Korteweg-de Vries (KdV) equation. While the first two moments are integrals of the KdV evolution, the 3rd and 4th moments undergo significant variations in the dominant interaction region, which could have strong effect on the values of the skewness and kurtosis in soliton turbulence.

Cross-Modulated Amplitudes and Frequencies Characterize Interacting Components in Complex Systems

NASA Astrophysics Data System (ADS)

Gans, Fabian; Schumann, Aicko Y.; Kantelhardt, Jan W.; Penzel, Thomas; Fietze, Ingo

2009-03-01

The dynamics of complex systems is characterized by oscillatory components on many time scales. To study the interactions between these components we analyze the cross modulation of their instantaneous amplitudes and frequencies, separating synchronous and antisynchronous modulation. We apply our novel technique to brain-wave oscillations in the human electroencephalogram and show that interactions between the α wave and the δ or β wave oscillators as well as spatial interactions can be quantified and related with physiological conditions (e.g., sleep stages). Our approach overcomes the limitation to oscillations with similar frequencies and enables us to quantify directly nonlinear effects such as positive or negative frequency modulation.

Bright and dark N-soliton solutions for the (2 + 1)-dimensional Maccari system

NASA Astrophysics Data System (ADS)

Liu, Lei; Tian, Bo; Yuan, Yu-Qiang; Sun, Yan

2018-02-01

Under investigation in this paper is the (2 + 1) -dimensional Maccari system, which is related to the Kadomtsev-Petviashvili (KP) equation. Bright and dark N -soliton solutions in terms of the Gramian are obtained via the KP hierarchy reduction. Oblique and parallel interactions between the bright solitons and between the dark solitons are studied analytically and graphically. We find that there are elastic and inelastic interactions for the bright solitons, but there are only elastic interactions for the dark solitons. Resonance, breather, attraction and repulsion structures are presented. It is expected that these soliton interactions have potential applications in fluid dynamics, nonlinear optics and plasma physics.

AVID - A design system for technology studies of advanced transportation concepts. [Aerospace Vehicle Interactive Design

NASA Technical Reports Server (NTRS)

Wilhite, A. W.; Rehder, J. J.

1979-01-01

The basic AVID (Aerospace Vehicle Interactive Design) is a general system for conceptual and preliminary design currently being applied to a broad range of future space transportation and spacecraft vehicle concepts. AVID hardware includes a minicomputer allowing rapid designer interaction. AVID software includes (1) an executive program and communication data base which provide the automated capability to couple individual programs, either individually in an interactive mode or chained together in an automatic sequence mode; and (2) the individual technology and utility programs which provide analysis capability in areas such as graphics, aerodynamics, propulsion, flight performance, weights, sizing, and costs.

The application of Arabidopsis thaliana in studying tripartite interactions among plants, beneficial fungal endophytes and biotrophic plant-parasitic nematodes.

PubMed

Martinuz, Alfonso; Zewdu, Getaneh; Ludwig, Nicole; Grundler, Florian; Sikora, Richard A; Schouten, Alexander

2015-04-01

The research demonstrated that Arabidopsis can be used as a model system for studying plant-nematode-endophyte tripartite interactions; thus, opening new possibilities for further characterizing the molecular mechanisms behind these interactions. Arabidopsis has been established as an important model system for studying plant biology and plant-microbe interactions. We show that this plant can also be used for studying the tripartite interactions among plants, the root-knot nematode Meloidogyne incognita and a beneficial endophytic isolate of Fusarium oxysporum, strain Fo162. In various plant species, Fo162 can systemically reduce M. incognita infection development and fecundity. Here it is shown that Fo162 can also colonize A. thaliana roots without causing disease symptoms, thus behaving as a typical endophyte. As observed for other plants, this endophyte could not migrate from the roots into the shoots and leaves. Direct inoculation of the leaves also did not result in colonization of the plant. A significant increase in plant fresh weight, root length and average root diameter was observed, suggesting the promotion of plant growth by the endophyte. The inoculation of A. thaliana with F. oxysporum strain Fo162 also resulted in a significant reduction in the number of M. incognita juveniles infecting the roots and ultimately the number of galls produced. This was also observed in a split-root experiment, in which the endophyte and nematode were spatially separated. The usefulness of Arabidopsis opens new possibilities for further dissecting complex tripartite interactions at the molecular and biochemical level.

Lone pair-π interactions in biological systems: occurrence, function, and physical origin.

PubMed

Kozelka, Jiří

2017-12-01

Lone pair-π interactions are now recognized as a supramolecular bond whose existence in biological systems is documented by a growing number of examples. They are commonly attributed to electrostatic forces. This review attempts to highlight some recent discoveries evidencing the important role which lone pair-π interactions, and anion-π interactions in particular, play in stabilizing the structure and affecting the function of biomolecules. Special attention is paid to studies exploring the physical origin of these at first glance counterintuitive interactions between a lone pair of electrons of one residue and the π-cloud of another. Recent theoretical work went beyond the popular electrostatic model and inquired the extent to which orbital interactions have to be taken into account. In at least one biologically relevant case-that of anion-flavin interactions-a substantial charge-transfer component has been shown to operate.

Interaction between Paracoccidioides brasiliensis conidia and the coagulation system: involvement of fibrinogen

PubMed Central

Tamayo, Diana; Hernández, Orville; Muñoz-Cadavid, Cesar; Cano, Luz Elena; González, Angel

2013-01-01

The infectious process starts with an initial contact between pathogen and host. We have previously demonstrated that Paracoccidioides brasiliensis conidia interact with plasma proteins including fibrinogen, which is considered the major component of the coagulation system. In this study, we evaluated the in vitro capacity of P. brasiliensis conidia to aggregate with plasma proteins and compounds involved in the coagulation system. We assessed the aggregation of P. brasiliensis conidia after incubation with human serum or plasma in the presence or absence of anticoagulants, extracellular matrix (ECM) proteins, metabolic and protein inhibitors, monosaccharides and other compounds. Additionally, prothrombin and partial thromboplastin times were determined after the interaction of P. brasiliensis conidia with human plasma. ECM proteins, monosaccharides and human plasma significantly induced P. brasiliensis conidial aggregation; however, anticoagulants and metabolic and protein inhibitors diminished the aggregation process. The extrinsic coagulation pathway was not affected by the interaction between P. brasiliensis conidia and plasma proteins, while the intrinsic pathway was markedly altered. These results indicate that P. brasiliensis conidia interact with proteins involved in the coagulation system. This interaction may play an important role in the initial inflammatory response, as well as fungal disease progression caused by P. brasiliensis dissemination. PMID:23827999

Cross-correlation spin noise spectroscopy of heterogeneous interacting spin systems

DOE PAGES

Roy, Dibyendu; Yang, Luyi; Crooker, Scott A.; ...

2015-04-30

Interacting multi-component spin systems are ubiquitous in nature and in the laboratory. As such, investigations of inter-species spin interactions are of vital importance. Traditionally, they are studied by experimental methods that are necessarily perturbative: e.g., by intentionally polarizing or depolarizing one spin species while detecting the response of the other(s). Here, we describe and demonstrate an alternative approach based on multi-probe spin noise spectroscopy, which can reveal inter-species spin interactions - under conditions of strict thermal equilibrium - by detecting and cross-correlating the stochastic fluctuation signals exhibited by each of the constituent spin species. Specifically, we consider a two-component spinmore » ensemble that interacts via exchange coupling, and we determine cross-correlations between their intrinsic spin fluctuations. The model is experimentally confirmed using “two-color” optical spin noise spectroscopy on a mixture of interacting Rb and Cs vapors. Noise correlations directly reveal the presence of inter-species spin exchange, without ever perturbing the system away from thermal equilibrium. These non-invasive and noise-based techniques should be generally applicable to any heterogeneous spin system in which the fluctuations of the constituent components are detectable.« less

The human mirror neuron system: A link between action observation and social skills

PubMed Central

Pineda, Jaime A.; Ramachandran, Vilayanur S.

2007-01-01

The discovery of the mirror neuron system (MNS) has led researchers to speculate that this system evolved from an embodied visual recognition apparatus in monkey to a system critical for social skills in humans. It is accepted that the MNS is specialized for processing animate stimuli, although the degree to which social interaction modulates the firing of mirror neurons has not been investigated. In the current study, EEG mu wave suppression was used as an index of MNS activity. Data were collected while subjects viewed four videos: (1) Visual White Noise: baseline, (2) Non-interacting: three individuals tossed a ball up in the air to themselves, (3) Social Action, Spectator: three individuals tossed a ball to each other and (4) Social Action, Interactive: similar to video 3 except occasionally the ball would be thrown off the screen toward the viewer. The mu wave was modulated by the degree of social interaction, with the Non-interacting condition showing the least suppression, followed by the Social Action, Spectator condition and the Social Action, Interactive condition showing the most suppression. These data suggest that the human MNS is specialized not only for processing animate stimuli, but specifically stimuli with social relevance. PMID:18985120

Gait synchronization in Caenorhabditis elegans

PubMed Central

Yuan, Jinzhou; Raizen, David M.; Bau, Haim H.

2014-01-01

Collective motion is observed in swarms of swimmers of various sizes, ranging from self-propelled nanoparticles to fish. The mechanisms that govern interactions among individuals are debated, and vary from one species to another. Although the interactions among relatively large animals, such as fish, are controlled by their nervous systems, the interactions among microorganisms, which lack nervous systems, are controlled through physical and chemical pathways. Little is known, however, regarding the mechanism of collective movements in microscopic organisms with nervous systems. To attempt to remedy this, we studied collective swimming behavior in the nematode Caenorhabditis elegans, a microorganism with a compact nervous system. We evaluated the contributions of hydrodynamic forces, contact forces, and mechanosensory input to the interactions among individuals. We devised an experiment to examine pair interactions as a function of the distance between the animals and observed that gait synchronization occurred only when the animals were in close proximity, independent of genes required for mechanosensation. Our measurements and simulations indicate that steric hindrance is the dominant factor responsible for motion synchronization in C. elegans, and that hydrodynamic interactions and genotype do not play a significant role. We infer that a similar mechanism may apply to other microscopic swimming organisms and self-propelled particles. PMID:24778261

The three-spined stickleback-Schistocephalus solidus system: an experimental model for investigating host-parasite interactions in fish.

PubMed

Barber, I; Scharsack, J P

2010-03-01

Plerocercoids of the pseudophyllidean cestode Schistocephalus solidus infect the three-spined stickleback Gasterosteus aculeatus, with important consequences for the biology of host fish. Techniques for culturing the parasite in vitro and generating infective stages that can be used to infect sticklebacks experimentally have been developed, and the system is increasingly used as a laboratory model for investigating aspects of host-parasite interactions. Recent experimental laboratory studies have focused on the immune responses of hosts to infection, the consequences of infection for the growth and reproductive development of host fish and the effects of infection on host behaviour. Here we introduce the host and the parasite, review the major findings of these recent experimental infection studies and identify further aspects of host parasite interactions that might be investigated using the system.

Spendency: Students' Propensity to Use System Currency

ERIC Educational Resources Information Center

Snow, Erica L.; Allen, Laura K.; Jackson, G. Tanner; McNamara, Danielle S.

2015-01-01

Using students' process data from the game-based Intelligent Tutoring System (ITS) iSTART-ME, the current study examines students' propensity to use system currency to unlock game-based features, (i.e., referred to here as "spendency"). This study examines how spendency relates to students' interaction preferences, in-system performance,…

Novel Fusion Protein Approach for Efficient High-Throughput Screening of Small Molecule–Mediating Protein-Protein Interactions in Cells and Living Animals

PubMed Central

Paulmurugan, Ramasamy; Gambhir, Sanjiv S.

2014-01-01

Networks of protein interactions execute many different intracellular pathways. Small molecules either synthesized within the cell or obtained from the external environment mediate many of these protein-protein interactions. The study of these small molecule–mediated protein-protein interactions is important in understanding abnormal signal transduction pathways in a variety of disorders, as well as in optimizing the process of drug development and validation. In this study, we evaluated the rapamycin-mediated interaction of the human proteins FK506-binding protein (FKBP12) rapamycin-binding domain (FRB) and FKBP12 by constructing a fusion of these proteins with a split-Renilla luciferase or a split enhanced green fluorescent protein (split-EGFP) such that complementation of the reporter fragments occurs in the presence of rapamycin. Different linker peptides in the fusion protein were evaluated for the efficient maintenance of complemented reporter activity. This system was studied in both cell culture and xenografts in living animals. We found that peptide linkers with two or four EAAAR repeat showed higher protein-protein interaction–mediated signal with lower background signal compared with having no linker or linkers with amino acid sequences GGGGSGGGGS, ACGSLSCGSF, and ACGSLSCGS-FACGSLSCGSF. A 9 ± 2-fold increase in signal intensity both in cell culture and in living mice was seen compared with a system that expresses both reporter fragments and the interacting proteins separately. In this fusion system, rapamycin induced heterodimerization of the FRB and FKBP12 moieties occurred rapidly even at very lower concentrations (0.00001 nmol/L) of rapamycin. For a similar fusion system employing split-EGFP, flow cytometry analysis showed significant level of rapamycin-induced complementation. PMID:16103094

Substituent Effects on the Self-Assembly/Coassembly and Hydrogelation of Phenylalanine Derivatives.

PubMed

Liyanage, Wathsala; Nilsson, Bradley L

2016-01-26

Supramolecular hydrogels derived from the self-assembly of organic molecules have been exploited for applications ranging from drug delivery to tissue engineering. The relationship between the structure of the assembly motif and the emergent properties of the resulting materials is often poorly understood, impeding rational approaches for the creation of next-generation materials. Aromatic π-π interactions play a significant role in the self-assembly of many supramolecular hydrogelators, but the exact nature of these interactions lacks definition. Conventional models that describe π-π interactions rely on quadrupolar electrostatic interactions between neighboring aryl groups in the π-system. However, recent experimental and computational studies reveal the potential importance of local dipolar interactions between elements of neighboring aromatic rings in stabilizing π-π interactions. Herein, we examine the nature of π-π interactions in the self- and coassembly of Fmoc-Phe-derived hydrogelators by systematically varying the electron-donating or electron-withdrawing nature of the side chain benzyl substituents and correlating these effects to the emergent assembly and gelation properties of the systems. These studies indicate a significant role for stabilizing dipolar interactions between neighboring benzyl groups in the assembled materials. Additional evidence for specific dipolar interactions is provided by high-resolution crystal structures obtained from dynamic transition of gel fibrils to crystals for several of the self-assembled/coassembled Fmoc-Phe derivatives. In addition to electronic effects, steric properties also have a significant effect on the interaction between neighboring benzyl groups in these assembled systems. These findings provide significant insight into the structure-function relationship for Fmoc-Phe-derived hydrogelators and give cues for the design of next-generation materials with desired emergent properties.

Ant-Plant Interaction in a Tropical Savanna: May the Network Structure Vary over Time and Influence on the Outcomes of Associations?

PubMed Central

Lange, Denise; Del-Claro, Kleber

2014-01-01

Plant-animal interactions occur in a community context of dynamic and complex ecological interactive networks. The understanding of who interacts with whom is a basic information, but the outcomes of interactions among associates are fundamental to draw valid conclusions about the functional structure of the network. Ecological networks studies in general gave little importance to know the true outcomes of interactions and how they may change over time. We evaluate the dynamic of an interaction network between ants and plants with extrafloral nectaries, by verifying the temporal variation in structure and outcomes of mutualism for the plant community (leaf herbivory). To reach this goal, we used two tools: bipartite network analysis and experimental manipulation. The networks exhibited the same general pattern as other mutualistic networks: nestedness, asymmetry and low specialization and this pattern was maintained over time, but with internal changes (species degree, connectance and ant abundance). These changes influenced the protection effectiveness of plants by ants, which varied over time. Our study shows that interaction networks between ants and plants are dynamic over time, and that these alterations affect the outcomes of mutualisms. In addition, our study proposes that the set of single systems that shape ecological networks can be manipulated for a greater understanding of the entire system. PMID:25141007

Biotic Interactions in Microbial Communities as Modulators of Biogeochemical Processes: Methanotrophy as a Model System

PubMed Central

Ho, Adrian; Angel, Roey; Veraart, Annelies J.; Daebeler, Anne; Jia, Zhongjun; Kim, Sang Yoon; Kerckhof, Frederiek-Maarten; Boon, Nico; Bodelier, Paul L. E.

2016-01-01

Microbial interaction is an integral component of microbial ecology studies, yet the role, extent, and relevance of microbial interaction in community functioning remains unclear, particularly in the context of global biogeochemical cycles. While many studies have shed light on the physico-chemical cues affecting specific processes, (micro)biotic controls and interactions potentially steering microbial communities leading to altered functioning are less known. Yet, recent accumulating evidence suggests that the concerted actions of a community can be significantly different from the combined effects of individual microorganisms, giving rise to emergent properties. Here, we exemplify the importance of microbial interaction for ecosystem processes by analysis of a reasonably well-understood microbial guild, namely, aerobic methane-oxidizing bacteria (MOB). We reviewed the literature which provided compelling evidence for the relevance of microbial interaction in modulating methane oxidation. Support for microbial associations within methane-fed communities is sought by a re-analysis of literature data derived from stable isotope probing studies of various complex environmental settings. Putative positive interactions between active MOB and other microbes were assessed by a correlation network-based analysis with datasets covering diverse environments where closely interacting members of a consortium can potentially alter the methane oxidation activity. Although, methanotrophy is used as a model system, the fundamentals of our postulations may be applicable to other microbial guilds mediating other biogeochemical processes. PMID:27602021

A computational study of anion-modulated cation-π interactions.

PubMed

Carrazana-García, Jorge A; Rodríguez-Otero, Jesús; Cabaleiro-Lago, Enrique M

2012-05-24

The interaction of anions with cation-π complexes formed by the guanidinium cation and benzene was thoroughly studied by means of computational methods. Potential energy surface scans were performed in order to evaluate the effect of the anion coming closer to the cation-π pair. Several structures of guanidinium-benzene complexes and anion approaching directions were examined. Supermolecule calculations were performed on ternary complexes formed by guanidinium, benzene, and one anion and the interaction energy was decomposed into its different two- and three-body contributions. The interaction energies were further dissected into their electrostatic, exchange, repulsion, polarization and dispersion contributions by means of local molecular orbital energy decomposition analysis. The results confirm that, besides the electrostatic cation-anion attraction, the effect of the anion over the cation-π interaction is mainly due to polarization and can be rationalized following the changes in the anion-π and the nonadditive (three-body) terms of the interaction. When the cation and the anion are on the same side of the π system, the three-body interaction is anticooperative, but when the anion and the cation are on opposite sides of the π system, the three-body interaction is cooperative. As far as we know, this is the first study where this kind of analysis is carried out with a structured cation as guanidinium with a significant biological interest.

Mean-field behavior in coupled oscillators with attractive and repulsive interactions.

PubMed

Hong, Hyunsuk; Strogatz, Steven H

2012-05-01

We consider a variant of the Kuramoto model of coupled oscillators in which both attractive and repulsive pairwise interactions are allowed. The sign of the coupling is assumed to be a characteristic of a given oscillator. Specifically, some oscillators repel all the others, thus favoring an antiphase relationship with them. Other oscillators attract all the others, thus favoring an in-phase relationship. The Ott-Antonsen ansatz is used to derive the exact low-dimensional dynamics governing the system's long-term macroscopic behavior. The resulting analytical predictions agree with simulations of the full system. We explore the effects of changing various parameters, such as the width of the distribution of natural frequencies and the relative strengths and proportions of the positive and negative interactions. For the particular model studied here we find, unexpectedly, that the mixed interactions produce no new effects. The system exhibits conventional mean-field behavior and displays a second-order phase transition like that found in the original Kuramoto model. In contrast to our recent study of a different model with mixed interactions [Phys. Rev. Lett. 106, 054102 (2011)], the π state and traveling-wave state do not appear for the coupling type considered here.

Simulator training with a forward collision warning system: effects on driver-system interactions and driver trust.

PubMed

Koustanaï, Arnaud; Cavallo, Viola; Delhomme, Patricia; Mas, Arnaud

2012-10-01

The study addressed the role of familiarization on a driving simulator with a forward collision warning (FCW) and investigated its impact on driver behavior. Drivers need a good understanding of how an FCW system functions to trust it and use it properly. Theoretical and empirical data suggest that exploring the capacities and limitations of the FCW during the learning period improves operating knowledge and leads to increased driver trust in the system and better driver-system interactions.The authors tested this hypothesis by comparing groups of drivers differing in FCW familiarity. During the familiarization phase, familiarized drivers were trained on the simulator using the FCW, unfamiliarized drivers simply read an FCW manual, and control drivers had no contact with the FCW. During the test, drivers drove the simulator and had to interact with traffic; both familiarized and unfamiliarized drivers used the FCW, whereas controls did not. Simulator familiarization improved driver understanding of FCW operation. Driver-system interactions were more effective: Familiarized drivers had no collisions, longer time headways, and better reactions in most situations. Familiarization increased trust in the FCW but did not raise system acceptance. Familiarization on the simulator had a positive effect on driver-system interactions and on trust in the system. The limitations of the familiarization method are discussed in relation to the driving simulator methodology. Practicing on a driving simulator with driving-assistance systems could facilitate their use during real driving.

Traffic impacts of bicycle facilities : final report.

DOT National Transportation Integrated Search

2017-06-01

Engineers need information about interactions between vehicles and bicyclists to design efficient, safe transportation systems. This study involved a review of design guidelines for bicycle facilities, observation of bicycle-vehicle interactions at n...

Interactions Among Plants, Insects, and Microbes: Elucidation of Inter-Organismal Chemical Communications in Agricultural Ecology.

PubMed

Beck, John J; Alborn, Hans; Block, Anna; Christensen, Shawn A; Hunter, Charles T; Rering, Caitlin C; Seidl-Adams, Irmgard; Stuhl, Charles; Torto, Baldwyn; Tumlinson, James H

2018-06-12

The last two decades have witnessed a sustained increase in the study of plant-emitted volatiles and their role in plant-insect, plant-microbe and plant-plant interactions. While each of these binary systems involves complex chemical and biochemical processes between two organisms, the progression of increasing complexity of a ternary system (i.e., plant-insect-microbe), and the study of a ternary system requires non-trivial planning. This planning can include: an experimental design that factors in potential overarching ecological interactions regarding the binary or ternary system; correctly identifying and understanding unexpected observations that may occur during the experiment; and, thorough interpretation of the resultant data. This challenge of planning, performing and interpreting a plant's defensive response to multiple biotic stressors will be even greater when abiotic stressors (i.e., temperature or water) are factored into the system. To fully understand the system, we need to not only continue to investigate and understand the volatile profiles, but also include and understand the biochemistry of the plant's response to these stressors. In this paper, we provide examples and discuss interaction considerations with respect to how readers and future authors of the Journal of Agricultural and Food Chemistry can contribute their expertise toward the extraction and interpretation of chemical information exchanged between agricultural commodities and their associated pests. This holistic, multidisciplinary and thoughtful approach to interactions of plants, insects, and microbes, and the resultant response of the plants, can lead to a better understanding of agricultural ecology, in turn leading to practical and viable solutions to agricultural problems.

Using porphyrin-amino acid pairs to model the electrochemistry of heme proteins: experimental and theoretical investigations.

PubMed

Samajdar, Rudra N; Manogaran, Dhivya; Yashonath, S; Bhattacharyya, Aninda J

2018-04-18

Quasi reversibility in electrochemical cycling between different oxidation states of iron is an often seen characteristic of iron containing heme proteins that bind dioxygen. Surprisingly, the system becomes fully reversible in the bare iron-porphyrin complex: hemin. This leads to the speculation that the polypeptide bulk (globin) around the iron-porphyrin active site in these heme proteins is probably responsible for the electrochemical quasi reversibility. To understand the effect of such polypeptide bulk on iron-porphyrin, we study the interaction of specific amino acids with the hemin center in solution. We choose three representative amino acids-histidine (a well-known iron coordinator in bio-inorganic systems), tryptophan (a well-known fluoroprobe for proteins), and cysteine (a redox-active organic molecule). The interactions of these amino acids with hemin are studied using electrochemistry, spectroscopy, and density functional theory. The results indicate that among these three, the interaction of histidine with the iron center is strongest. Further, histidine maintains the electrochemical reversibility of iron. On the other hand, tryptophan and cysteine interact weakly with the iron center but disturb the electrochemical reversibility by contributing their own redox active processes to the system. Put together, this study attempts to understand the molecular interactions that can control electrochemical reversibility in heme proteins. The results obtained here from the three representative amino acids can be scaled up to build a heme-amino acid interaction database that may predict the electrochemical properties of any protein with a defined polypeptide sequence.

Steady bipartite coherence induced by non-equilibrium environment

NASA Astrophysics Data System (ADS)

Huangfu, Yong; Jing, Jun

2018-01-01

We study the steady state of two coupled two-level atoms interacting with a non-equilibrium environment that consists of two heat baths at different temperatures. Specifically, we analyze four cases with respect to the configuration about the interactions between atoms and heat baths. Using secular approximation, the conventional master equation usually neglects steady-state coherence, even when the system is coupled with a non-equilibrium environment. When employing the master equation with no secular approximation, we find that the system coherence in our model, denoted by the off-diagonal terms in the reduced density matrix spanned by the eigenvectors of the system Hamiltonian, would survive after a long-time decoherence evolution. The absolute value of residual coherence in the system relies on different configurations of interaction channels between the system and the heat baths. We find that a large steady quantum coherence term can be achieved when the two atoms are resonant. The absolute value of quantum coherence decreases in the presence of additional atom-bath interaction channels. Our work sheds new light on the mechanism of steady-state coherence in microscopic quantum systems in non-equilibrium environments.

Experimental Aspects of Colloidal Interactions in Mixed Systems of Liposome and Inorganic Nanoparticle and Their Applications

PubMed Central

Michel*, Raphael; Gradzielski*, Michael

2012-01-01

In the past few years, growing attention has been devoted to the study of the interactions taking place in mixed systems of phospholipid membranes (for instance in the form of vesicles) and hard nanoparticles (NPs). In this context liposomes (vesicles) may serve as versatile carriers or as a model system for biological membranes. Research on these systems has led to the observation of novel hybrid structures whose morphology strongly depends on the charge, composition and size of the interacting colloidal species as well as on the nature (pH, ionic strength) of their dispersing medium. A central role is played by the phase behaviour of phospholipid bilayers which have a tremendous influence on the liposome properties. Another central aspect is the incorporation of nanoparticles into vesicles, which is intimately linked to the conditions required for transporting a nanoparticle through a membrane. Herein, we review recent progress made on the investigations of the interactions in liposome/nanoparticle systems focusing on the particularly interesting structures that are formed in these hybrid systems as well as their potential applications. PMID:23109874

Bimolecular interaction of argpyrimidine (a Maillard reaction product) in in vitro non-enzymatic protein glycation model and its potential role as an antiglycating agent.

PubMed

Bhattacherjee, Abhishek; Dhara, Kaliprasanna; Chakraborti, Abhay Sankar

2017-09-01

Non- enzymatic glycation, also known as Maillard reaction, is one of the most important and investigated reactions in biochemistry. Maillard reaction products (MRPs) like protein-derived advanced glycation end products (AGEs) are often referred to cause pathophysiological complications in human systems. On contrary, several MRPs are exogenously used as antioxidant, antimicrobial and flavouring agents. In the preset study, we have shown that argpyrimidine, a well-established AGE, interacts with bovine serum albumin (BSA) and glucose individually in standard BSA-glucose model system and successfully inhibits glycation of the protein. Bimolecular interaction of argpyrimidine with glucose or BSA has been studied independently. Chromatographic purification, different spectroscopic studies and molecular modeling have been used to evaluate the nature and pattern of interactions. Binding of argpyrimidine with BSA prevents incorporation of glucose inside the native protein. Argpyrimidine can also directly entrap glucose. Both these interactions may be associated with the antiglycation potential of argpyrimidine, indicating a beneficial function of an AGE. Copyright © 2017 Elsevier B.V. All rights reserved.

The Pseudopod System for Axon-Glia Interactions: Stimulation and Isolation of Schwann Cell Protrusions that Form in Response to Axonal Membranes.

PubMed

Poitelon, Yannick; Feltri, M Laura

2018-01-01

In the peripheral nervous system, axons dictate the differentiation state of Schwann cells. Most of this axonal influence on Schwann cells is due to juxtacrine interactions between axonal transmembrane molecules (e.g., the neuregulin growth factor) and receptors on the Schwann cell (e.g., the ErbB2/ErbB3 receptor). The fleeting nature of this interaction together with the lack of synchronicity in the development of the Schwann cell population limits our capability to study this phenomenon in vivo. Here we present a simple Boyden Chamber-based method to study this important cell-cell interaction event. We isolate the early protrusions of Schwann cells that are generated in response to juxtacrine stimulation by sensory neuronal membranes. This method is compatible with a large array of current biochemical analyses and provides an effective approach to study biomolecules that are differentially localized in Schwann cell protrusions and cell bodies in response to axonal signals. A similar approach can be extended to different kinds of cell-cell interactions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marion, Antoine; Monard, Gérald; Ruiz-López, Manuel F., E-mail: Manuel.Ruiz@univ-lorraine.fr

In this work, we present a study of the ability of different semiempirical methods to describe intermolecular interactions in water solution. In particular, we focus on methods based on the Neglect of Diatomic Differential Overlap approximation. Significant improvements of these methods have been reported in the literature in the past years regarding the description of non-covalent interactions. In particular, a broad range of methodologies has been developed to deal with the properties of hydrogen-bonded systems, with varying degrees of success. In contrast, the interactions between water and a molecule containing hydrophobic groups have been little analyzed. Indeed, by considering themore » potential energy surfaces obtained using different semiempirical Hamiltonians for the intermolecular interactions of model systems, we found that none of the available methods provides an entirely satisfactory description of both hydrophobic and hydrophilic interactions in water. In addition, a vibrational analysis carried out in a model system for these interactions, a methane clathrate cluster, showed that some recent methods cannot be used to carry out studies of vibrational properties. Following a procedure established in our group [M. I. Bernal-Uruchurtu, M. T. C. Martins-Costa, C. Millot, and M. F. Ruiz-López, J. Comput. Chem. 21, 572 (2000); W. Harb, M. I. Bernal-Uruchurtu, and M. F. Ruiz-López, Theor. Chem. Acc. 112, 204 (2004)], we developed new parameters for the core-core interaction terms based on fitting potential energy curves obtained at the MP2 level for our model system. We investigated the transferability of the new parameters to describe a system, having both hydrophilic and hydrophobic groups, interacting with water. We found that only by introducing two different sets of parameters for hydrophilic and hydrophobic hydrogen atom types we are able to match the features of the ab initio calculated properties. Once this assumption is made, a good agreement with the MP2 reference is achieved. The results reported in this work provide therefore a direction for future developments of semiempirical approaches that are still required to investigate chemical processes in biomolecules and in large disordered systems.« less

Interactions of diamines with adenosine-5'-triphosphate (ATP) in the systems including copper(II) ions.

PubMed

Bregier-Jarzebowska, R; Gasowska, A; Hoffmann, S K; Lomozik, L

2016-09-01

Interactions were studied in the systems ATP/tn and ATP/Put (tn=1,3-diaminopropane, Put=putrescine) whereas the complexation reactions in ternary systems Cu(II)/ATP/tn and Cu(II)/ATP/Put. Results of the potentiometric and spectroscopic studies evidenced the formation of adducts of the type (ATP)H x (PA), where PA=diamine. The thermodynamic stability of the complexes and the mode of interactions were determined. On the basis of analysis of changes in the positions of NMR signals, in the pH range of (ATP)H 3 (Put) formation, the preferred centres of the interaction between ATP and Put are the endocyclic nitrogen atoms from the nucleotide. On the other hand, the shorter diamine tn in the entire pH range reacts with the phosphate groups from ATP. The positive centres of noncovalent interactions are the protonated NH x + groups from amines. In both complexes Cu(ATP)H 2 (tn) and Cu(ATP)H 3 (Put) formed in ternary systems at pH<6.5, the amines are in the outer sphere of coordination with the noncovalent interaction with anchoring Cu(ATP). Only the phosphate groups from the nucleotide take part in metalation. At higher pH in the range of Cu(ATP)(PA) complex formation, significant differences in the reactions of the two amines appear. The shorter one (tn) binds Cu(II) ions with two nitrogen atoms, while putrescine coordinates in the monofunctional mode, which is undoubtedly related to the differences in lengths of methylene chain. This explains the considerable differences in the stability of Cu(ATP)(tn) and Cu(ATP)(Put). In both complexes the nucleotide is coordinated through phosphate groups. As a result of noncovalent interactions ATP forms molecular complexes with 1,3-diaminopropane and 1,4-diaminobutane (putrescine). Significant differences in the mode of interactions between the two diamines were observed in ATP/diamine binary systems and in ternary systems Cu(II)/ATP/diamine, at high pH. Copyright © 2016 Elsevier Inc. All rights reserved.

Correlational approach to study interactions between dust Brownian particles in a plasma

NASA Astrophysics Data System (ADS)

Lisin, E. A.; Vaulina, O. S.; Petrov, O. F.

2018-01-01

A general approach to the correlational analysis of Brownian motion of strongly coupled particles in open dissipative systems is described. This approach can be applied to the theoretical description of various non-ideal statistically equilibrium systems (including non-Hamiltonian systems), as well as for the analysis of experimental data. In this paper, we consider an application of the correlational approach to the problem of experimental exploring the wake-mediated nonreciprocal interactions in complex plasmas. We derive simple analytic equations, which allows one to calculate the gradients of forces acting on a microparticle due to each of other particles as well as the gradients of external field, knowing only the information on time-averaged correlations of particles displacements and velocities. We show the importance of taking dissipative and random processes into account, without which consideration of a system with a nonreciprocal interparticle interaction as linearly coupled oscillators leads to significant errors in determining the characteristic frequencies in a system. In the examples of numerical simulations, we demonstrate that the proposed original approach could be an effective instrument in exploring the longitudinal wake structure of a microparticle in a plasma. Unlike the previous attempts to study the wake-mediated interactions in complex plasmas, our method does not require any external perturbations and is based on Brownian motion analysis only.

Dynamics of correlations in long-range quantum systems follwing a quantum quench

NASA Astrophysics Data System (ADS)

Cevolani, Lorenzo; Carleo, Giuseppe; Sanchez-Palencia, Laurent

We study how and how fast correlations can spread in a quantum system abruptly driven out of equilibrium by a quantum quench. This protocol can be experimentally realized and it allow to address fundamental questions concerning the quasi-locality principle in isolated quantum systems with both short- and long-range interactions. We focus on two different models describing, respectively, lattice bosons, and spins. Our study is based on a combined approach, based on one hand on accurate many-body numerical calculations and on the other hand on a quasi-particle microscopic theory. We find that, for sufficiently fast decaying interaction potential the propagation is ballistic and the Lieb-Robinson bounds for long-range interactions are never attained. When the interactions are really long-range, the scenario is completely different in the two cases. In the bosonic system the locality is preserved and a ballistic propagation is still present while in the spin system an instantaneous propagation of correlations completely destroys locality. Using the microscopic point of view we can quantitatively describe all the different regimes, from instantaneous to ballistic, found in the spin model and we explain how locality is protected in the bosonic model leading to a ballistic propagation. ERC (FP7/2007-2013 No. 256294), QUIC (H2020 No. 641122).

The 2ν6/ν2 + ν3/ν3 + ν5 band system of CH3Br revisited: Modeling anharmonic and Coriolis interactions in a three-level system near 2000 cm-1

NASA Astrophysics Data System (ADS)

Ceausu-Velcescu, Adina; Kwabia Tchana, Fridolin; Landsheere, Xavier

2018-06-01

The 2ν6 (A1 + E)/ν2 + ν3 (A1)/ν3 + ν5 (E) band system of CH3Br, near 2000 cm-1, has been studied, for both 79Br and 81Br isotopologues, using Fourier transform infrared spectroscopy, with a resolution of 0.003 cm-1. This band system, revealing anharmonic (Δk = Δl = 0) and Coriolis (Δk = Δl = ± 1) interactions, has been analyzed through a least-squares fit of more than 3000 transitions, for each isotopologue. More than 600 transitions belonging to the very weak ν3 + ν5 combination band were assigned for the first time, for both CH379Br and CH381Br isotopologues. Assignments of the weak 2 ν60 parallel band, which is Fermi-interacting with ν2 + ν3, were also considerably extended with respect to a previous high-resolution study (Najib et al., 1985), thanks to a more accurate knowledge of the Fermi coupling parameters and of the relative positions of the interacting levels. The least-squares fits provided quantitative reproduction of all data belonging to the four above mentioned bands. Moreover, the Coriolis coupling parameters obtained for the ν2 + ν3/ν3 + ν5 interacting bands show a remarkable consistency with those obtained for the ν2/ν5 'fundamental' system (Kwabia Tchana et al., 2004).

Contaminant-State Broadening Mechanism in a Driven Dissipative Rydberg System

NASA Astrophysics Data System (ADS)

Porto, J. V.

2017-04-01

The strong interactions in Rydberg atoms make them an ideal system for the study of correlated many-body physics, both in the presence and absence of dissipation. Using such highly excited atomic states requires addressing challenges posed by the dense spectrum of Rydberg levels, the detrimental effects of spontaneous emission, and strong interactions. A full understanding of the scope and limitations of many Rydberg-based proposals requires simultaneously including these effects, which typically cannot be described by a mean-field treatment due to correlations in the quantum coherent and dissipative processes. We study a driven, dissipative system of Rydberg atoms in a 3D optical lattice, and observe substantial deviation from single-particle excitation rates, both on and off resonance. The observed broadened spectra cannot be explained by van der Waals interactions or a mean-field treatment of the system. Based on the magnitude of the broadening and the scaling with density and two-photon Rabi frequency, we attribute these effects to unavoidable blackbody-induced transitions to nearby Rydberg states of opposite parity, which have large, resonant dipole-dipole interactions with the state of interest. Even at low densities of Rydberg atoms, uncontrolled production of atoms in other states significantly modifies the energy levels of the remaining atoms. These off-diagonal exchange interactions result in complex many-body states of the system and have implications for off-resonant Rydberg dressing proposals. This work was partially supported by the ARL-CDQI program.

Climate and Energy-Water-Land System Interactions Technical Report to the U.S. Department of Energy in Support of the National Climate Assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skaggs, Richard; Hibbard, Kathleen A.; Frumhoff, Peter

2012-03-01

This report provides a framework to characterize and understand the important elements of climate and energy-water-land (EWL) system interactions. It identifies many of the important issues, discusses our understanding of those issues, and presents a long-term research program research needs to address the priority scientific challenges and gaps in our understanding. Much of the discussion is organized around two discrete case studies with the broad themes of (1) extreme events and (2) regional intercomparisons. These case studies help demonstrate unique ways in which energy-water-land interactions can occur and be influenced by climate.

Sleep and immune function: glial contributions and consequences of aging

PubMed Central

Ingiosi, Ashley M.; Opp, Mark R.; Krueger, James M.

2013-01-01

The reciprocal interactions between sleep and immune function are well-studied. Insufficient sleep induces innate immune responses as evidenced by increased expression of pro-inflammatory mediators in the brain and periphery. Conversely, immune challenges upregulate immunomodulator expression, which alters central nervous system-mediated processes and behaviors, including sleep. Recent studies indicate that glial cells, namely microglia and astrocytes, are active contributors to sleep and immune system interactions. Evidence suggests glial regulation of these interactions is mediated, in part, by adenosine and adenosine 5′-triphosphate actions at purinergic type 1 and type 2 receptors. Furthermore, microglia and astrocytes may modulate declines in sleep-wake behavior and immunity observed in aging. PMID:23452941

Sleep and immune function: glial contributions and consequences of aging.

PubMed

Ingiosi, Ashley M; Opp, Mark R; Krueger, James M

2013-10-01

The reciprocal interactions between sleep and immune function are well-studied. Insufficient sleep induces innate immune responses as evidenced by increased expression of pro-inflammatory mediators in the brain and periphery. Conversely, immune challenges upregulate immunomodulator expression, which alters central nervous system-mediated processes and behaviors, including sleep. Recent studies indicate that glial cells, namely microglia and astrocytes, are active contributors to sleep and immune system interactions. Evidence suggests glial regulation of these interactions is mediated, in part, by adenosine and adenosine 5'-triphosphate actions at purinergic type 1 and type 2 receptors. Furthermore, microglia and astrocytes may modulate declines in sleep-wake behavior and immunity observed in aging. Copyright © 2013. Published by Elsevier Ltd.

On the control of spin-boson systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boscain, Ugo, E-mail: ugo.boscain@polytechnique.edu; Mason, Paolo, E-mail: Paolo.Mason@l2s.centralesupelec.fr; Panati, Gianluca, E-mail: panati@mat.uniroma1.it

2015-09-15

In this paper, we study the so-called spin-boson system, namely, a two-level system in interaction with a distinguished mode of a quantized bosonic field. We give a brief description of the controlled Rabi and Jaynes–Cummings models and we discuss their appearance in the mathematics and physics literature. We then study the controllability of the Rabi model when the control is an external field acting on the bosonic part. Applying geometric control techniques to the Galerkin approximation and using perturbation theory to guarantee non-resonance of the spectrum of the drift operator, we prove approximate controllability of the system, for almost everymore » value of the interaction parameter.« less

Patterns of Relating between Mothers and Preschool-Aged Children Using the Marschak Interaction Method Rating System

ERIC Educational Resources Information Center

Martin, Erin E.; Snow, Marilyn S.; Sullivan, Kathleen

2008-01-01

This study assesses the relationship of patterns of relating between mothers and their preschool-aged children. Thirty-one families were used, and the mother and child participated in the Marschak Interaction Method Rating System (MIM-RS). Mothers also completed the Demographic Data Questionnaire. Correlations based upon the MIM-RS for mothers and…

Effects of Prior Knowledge in Mathematics on Learner-Interface Interactions in a Learning-by-Teaching Intelligent Tutoring System

ERIC Educational Resources Information Center

Bringula, Rex P.; Basa, Roselle S.; Dela Cruz, Cecilio; Rodrigo, Ma. Mercedes T.

2016-01-01

This study attempted to determine the influence of prior knowledge in mathematics of students on learner-interface interactions in a learning-by-teaching intelligent tutoring system. One hundred thirty-nine high school students answered a pretest (i.e., the prior knowledge in mathematics) and a posttest. In between the pretest and posttest, they…

Duration of classicality in highly degenerate interacting Bosonic systems

DOE PAGES

Sikivie, Pierre; Todarello, Elisa M.

2017-04-28

We study sets of oscillators that have high quantum occupancy and that interact by exchanging quanta. It is shown by analytical arguments and numerical simulation that such systems obey classical equations of motion only on time scales of order their relaxation time τ and not longer than that. The results are relevant to the cosmology of axions and axion-like particles.

Advancing the Assessment of Parent-Child Interactions: Development of the Parent Instruction-Giving Game with Youngsters

ERIC Educational Resources Information Center

Hupp, Stephen D. A.; Reitman, David; Forde, Debra A.; Shriver, Mark D.; Kelley, Mary Lou

2008-01-01

This study investigates the validity of the Parent Instruction-Giving Game with Youngsters (PIGGY), a newly developed direct-observation system. The PIGGY is a derivative of the Dyadic Parent-Child Interaction Coding System II [DPICS-II; Eyberg, S. M., Bessmer, J., Newcomb, K., Edwards, D., Robinson, E. (1994). Manual for the Dyadic Parent-Child…

Space station propulsion-ECLSS interaction study

NASA Technical Reports Server (NTRS)

Brennan, Scott M.

1986-01-01

The benefits of the utilization of effluents of the Space Station Environmental Control and Life Support (ECLS) system are examined. Various ECLSS-propulsion system interaction options are evaluated and compared on the basis of weight, volume, and power requirements. Annual propulsive impulse to maintain station altitude during a complete solar cycle of eleven years and the effect on station resupply are considered.

Corticospinal excitability during the observation of social behavior.

PubMed

Bucchioni, Giulia; Cavallo, Andrea; Ippolito, Davide; Marton, Gianluca; Castiello, Umberto

2013-03-01

Evidence suggests that the observation of an action induces in the observers an enhancement of motor evoked potentials (MEPs) recorded by the observer's muscles corresponding to those involved in the observed action. Although this is a well-studied phenomenon, it remains still unclear how the viewer's motor facilitation is influenced by the social content characterizing the observed scene. In the present study we investigated the facilitation of the corticospinal system during the observation of either an action that does not imply a social interaction (i.e., an actor throwing a ball against a wall), or an action which implies a social interaction (i.e., an actor passing a ball to a partner). Results indicate that MEPs amplitude is enhanced during the observation of a social rather than an individual action. We contend that the increase in MEPs activation might reflect an enhancement of the simulative activity stemming from the mirror system during the observation of social interactions. Altogether these findings show that the human corticospinal system is sensitive to social interactions and may support the role of the mirror neurons system in social cognition. Copyright © 2012 Elsevier Inc. All rights reserved.

Thermal transport in the Fermi-Pasta-Ulam model with long-range interactions

NASA Astrophysics Data System (ADS)

Bagchi, Debarshee

2017-03-01

We study the thermal transport properties of the one-dimensional Fermi-Pasta-Ulam model (β type) with long-range interactions. The strength of the long-range interaction decreases with the (shortest) distance between the lattice sites as distance-δ, where δ ≥0 . Two Langevin heat baths at unequal temperatures are connected to the ends of the one-dimensional lattice via short-range harmonic interactions that drive the system away from thermal equilibrium. In the nonequilibrium steady state the heat current, thermal conductivity, and temperature profiles are computed by solving the equations of motion numerically. It is found that the conductivity κ has an interesting nonmonotonic dependence with δ with a maximum at δ =2.0 for this model. Moreover, at δ =2.0 ,κ diverges almost linearly with system size N and the temperature profile has a negligible slope, as one expects in ballistic transport for an integrable system. We demonstrate that the nonmonotonic behavior of the conductivity and the nearly ballistic thermal transport at δ =2.0 obtained under nonequilibrium conditions can be explained consistently by studying the variation of largest Lyapunov exponent λmax with δ , and excess energy diffusion in the equilibrium microcanonical system.

Interaction of Antitumor Agent Mitoxantrone with Double Helical Synthetic Polyribonucleotides Poly(G)ṡPoly(C) and Poly(I)ṡPoly(C)

NASA Astrophysics Data System (ADS)

Babayan, Yuri S.; Hakobyan, Sergey N.; Ghazaryan, Rusanna S.; Shahinyan, Mariam A.

The interaction of antitumor drug mitoxantrone (MTX) with double-stranded synthetic RNA homopolymers has been studied by means of spectroscopic (UV-Visible absorption, circular dichroism) techniques. The results show a base specificity in this interaction: the association constant with poly(G)ṡpoly(C) is higher than with poly(I)ṡpoly(C). Values of changes of the system enthalpy and entropy due to complex-formation were determined through the temperature dependence of the binding constant. Calculations show that due to the intercalation interaction of MTX, the values of changes of the system entropy and enthalpy differ from those obtained at ehtidium bromide interaction with synthetic polyribonucleotides, which shows that the intercalation interaction of MTX with double-stranded RNA significantly differs from that of ethidium bromide with RNA.

Research of Environmental and Economic Interactions of Coke And By-Product Process

NASA Astrophysics Data System (ADS)

Mikhailov, Vladimir; Kiseleva, Tamara; Bugrova, Svetlana; Muromtseva, Alina; Mikhailova, Yana

2017-11-01

The issues of showing relations between environmental and economic indicators (further - environmental and economic interactions) of coke and by-product process are considered in the article. The purpose of the study is to reveal the regularities of the functioning of the local environmental and economic system on the basis of revealed spectrum of environmental and economic interactions. A simplified scheme of the environmental and economic system "coke and by-product process - the environment" was developed. The forms of the investigated environmental-economic interactions were visualized and the selective interpretation of the tightness of the established connection was made. The main result of the work is modeling system of environmental and economic interactions that allows increasing the efficiency of local ecological and economic system management and optimizing the "interests" of an industrial enterprise - the source of negative impact on the environment. The results of the survey can be recommended to government authorities and industrial enterprises with a wide range of negative impact forms to support the adoption of effective management decisions aimed at sustainable environmental and economic development of the region or individual municipalities.

Comprehending emergent systems phenomena through direct-manipulation animation

NASA Astrophysics Data System (ADS)

Aguirre, Priscilla Abel

This study seeks to understand the type of interaction mode that best supports learning and comprehension of emergent systems phenomena. Given that the literature has established that students hold robust misconceptions of such phenomena, this study investigates the influence of using three types of interaction; speed-manipulation animation (SMN), post-manipulation animation (PMA) and direct-manipulation animation (DMA) for increasing comprehension and testing transfer of the phenomena, by looking at the effect of simultaneous interaction of haptic and visual channels on long term and working memories when seeking to comprehend emergent phenomena. The questions asked were: (1) Does the teaching of emergent phenomena, with the aid of a dynamic interactive modeling tool (i.e., SMA, PMA or DMA), improve students' mental model construction of systems, thus increasing comprehension of this scientific concept? And (2) does the teaching of emergent phenomena, with the aid of a dynamic interactive modeling tool, give the students the necessary complex cognitive skill which can then be applied to similar (near transfer) and/or novel, but different, (far transfer) scenarios? In an empirical study undergraduate and graduate students were asked to participate in one of three experimental conditions: SMA, PMA, or DMA. The results of the study found that it was the participants of the SMA treatment condition that had the most improvement in post-test scores. Students' understanding of the phenomena increased most when they used a dynamic model with few interactive elements (i.e., start, stop, and speed) that allowed for real time visualization of one's interaction on the phenomena. Furthermore, no indication was found that the learning of emergent phenomena, with the aid of a dynamic interactive modeling tool, gave the students the necessary complex cognitive skill which could then be applied to similar (near transfer) and/or novel, but different, (far transfer) scenarios. Finally, besides treatment condition, gender and age were also shown to be predictors of score differences; overall, males did better than females, and younger students did better than older students.

Multimedia Interactive eBooks in Laboratory Bioscience Education

ERIC Educational Resources Information Center

Morris, Neil P.; Lambe, James

2017-01-01

Bioscience students in the UK higher education system are making increasing use of technology to support their learning within taught classes and during private study. This experimental study was designed to assess the role for multimedia interactive eBooks in bioscience laboratory classes, delivered using a blended learning approach. Thirty-nine…

Mutualism and Antagonism: Ecological Interactions Among Bark Beetles, Mite and Fungi

Treesearch

K.D. Klepzig; J.C. Moser; M.J. Lombardero; M.P. Ayres; R.W. Hofstetter; C.J. Walkinshaw

2001-01-01

Insect-fungal complexes provide challenging and fascinating systems for the study of biotic interactions between plants. plant pathogens, insect vectors and other associated organisms. The types of interactions among these organisms (mutualism. antagonism. parasitism. phoresy. etc.) are as variable as the range of organisms involved (plants, fungi, insects. mites. etc...

Young Pianists Exploring Improvisation Using Interactive Music Technology

ERIC Educational Resources Information Center

Rowe, Victoria; Triantafyllaki, Angeliki; Anagnostopoulou, Xristina

2015-01-01

The use of music technology in the enhancement of young pianists' musical improvisations has been scarcely explored in instrumental music teaching and learning research. In the present study, 19 piano pupils aged 6-10 from the UK and Greece used an interactive improvisation system called Musical Interaction Relying On Reflexion (MIROR)-Impro for…

Interactive Videoconference Supported Teaching in Undergraduate Nursing: A Case Study for ECG

ERIC Educational Resources Information Center

Celikkan, Ufuk; Senuzun, Fisun; Sari, Dilek; Sahin, Yasar Guneri

2013-01-01

This paper describes how interactive videoconference can benefit the Electrocardiography (ECG) skills of undergraduate nursing students. We have implemented a learning system that interactively transfers the visual and practical aspects of ECG from a nursing skills lab into a classroom where the theoretical part of the course is taught. The…

The Study of the Interaction between Silica Filler and Silicone Rubber

NASA Astrophysics Data System (ADS)

Liu, Jiesheng; Gong, Xiaoqiang; Zhang, Rongtang

2018-01-01

The interaction between silica filler and silicone rubber was studied by swelling ratio, Kraus curve and crosslinking density test. The results showed that lower values of Vro/Vrf and swelling ratio in modified filler system suggests good filler-matrix interactions. The composites with silane coupling agents show higher crosslink-density compared that of untreated ones. In the light of the above statement, it can be concluded that modification of filler is the crucial factor in creating a good interaction between the filler and silicone rubber.

A rice kinase-protein interaction map.

PubMed

Ding, Xiaodong; Richter, Todd; Chen, Mei; Fujii, Hiroaki; Seo, Young Su; Xie, Mingtang; Zheng, Xianwu; Kanrar, Siddhartha; Stevenson, Rebecca A; Dardick, Christopher; Li, Ying; Jiang, Hao; Zhang, Yan; Yu, Fahong; Bartley, Laura E; Chern, Mawsheng; Bart, Rebecca; Chen, Xiuhua; Zhu, Lihuang; Farmerie, William G; Gribskov, Michael; Zhu, Jian-Kang; Fromm, Michael E; Ronald, Pamela C; Song, Wen-Yuan

2009-03-01

Plants uniquely contain large numbers of protein kinases, and for the vast majority of the 1,429 kinases predicted in the rice (Oryza sativa) genome, little is known of their functions. Genetic approaches often fail to produce observable phenotypes; thus, new strategies are needed to delineate kinase function. We previously developed a cost-effective high-throughput yeast two-hybrid system. Using this system, we have generated a protein interaction map of 116 representative rice kinases and 254 of their interacting proteins. Overall, the resulting interaction map supports a large number of known or predicted kinase-protein interactions from both plants and animals and reveals many new functional insights. Notably, we found a potential widespread role for E3 ubiquitin ligases in pathogen defense signaling mediated by receptor-like kinases, particularly by the kinases that may have evolved from recently expanded kinase subfamilies in rice. We anticipate that the data provided here will serve as a foundation for targeted functional studies in rice and other plants. The application of yeast two-hybrid and TAPtag analyses for large-scale plant protein interaction studies is also discussed.

Radiative interactions in transient energy transfer in gaseous systems

NASA Technical Reports Server (NTRS)

Tiwari, S. N.

1985-01-01

Analyses and numerical procedures are presented to investigate the radiative interactions in transient energy transfer processes in gaseous systems. The nongray radiative formulations are based on the wide-band model correlations for molecular absorption. Various relations for the radiative flux are developed; these are useful for different flow conditions and physical problems. Specific plans for obtaining extensive results for different cases are presented. The methods presented in this study can be extended easily to investigate the radiative interactions in realistic flows of hydrogen-air species in the scramjet engine.

Pollen–pistil interactions and self-incompatibility in the Asteraceae: new insights from studies of Senecio squalidus (Oxford ragwort)

PubMed Central

Allen, Alexandra M.; Thorogood, Christopher J.; Hegarty, Matthew J.; Lexer, Christian; Hiscock, Simon J.

2011-01-01

Background Pollen–pistil interactions are an essential prelude to fertilization in angiosperms and determine compatibility/incompatibility. Pollen–pistil interactions have been studied at a molecular and cellular level in relatively few families. Self-incompatibility (SI) is the best understood pollen–pistil interaction at a molecular level where three different molecular mechanisms have been identified in just five families. Here we review studies of pollen–pistil interactions and SI in the Asteraceae, an important family that has been relatively understudied in these areas of reproductive biology. Scope We begin by describing the historical literature which first identified sporophytic SI (SSI) in species of Asteraceae, the SI system later identified and characterized at a molecular level in the Brassicaceae. Early structural and cytological studies in these two families suggested that pollen–pistil interactions and SSI were similar, if not the same. Recent cellular and molecular studies in Senecio squalidus (Oxford ragwort) have challenged this belief by revealing that despite sharing the same genetic system of SSI, the Brassicaceae and Asteraceae molecular mechanisms are different. Key cellular differences have also been highlighted in pollen–stigma interactions, which may arise as a consequence of the Asteraceae possessing a ‘semi-dry’ stigma, rather than the ‘dry’ stigma typical of the Brassicaceae. The review concludes with a summary of recent transcriptomic analyses aimed at identifying proteins regulating pollen–pistil interactions and SI in S. squalidus, and by implication the Asteraceae. The Senecio pistil transcriptome contains many novel pistil-specific genes, but also pistil-specific genes previously shown to play a role in pollen–pistil interactions in other species. Conclusions Studies in S. squalidus have shown that stigma structure and the molecular mechanism of SSI in the Asteraceae and Brassicaceae are different. The availability of a pool of pistil-specific genes for S. squalidus offers an opportunity to elucidate the molecular mechanisms of pollen–pistil interactions and SI in the Asteraceae. PMID:21752792

One-dimensional continuum electronic structure with the density-matrix renormalization group and its implications for density-functional theory.

PubMed

Stoudenmire, E M; Wagner, Lucas O; White, Steven R; Burke, Kieron

2012-08-03

We extend the density matrix renormalization group to compute exact ground states of continuum many-electron systems in one dimension with long-range interactions. We find the exact ground state of a chain of 100 strongly correlated artificial hydrogen atoms. The method can be used to simulate 1D cold atom systems and to study density-functional theory in an exact setting. To illustrate, we find an interacting, extended system which is an insulator but whose Kohn-Sham system is metallic.

Novel Television-Based Cognitive Training Improves Working Memory and Executive Function

PubMed Central

Shatil, Evelyn; Mikulecká, Jaroslava; Bellotti, Francesco; Bureš, Vladimír

2014-01-01

The main study objective was to investigate the effect of interactive television-based cognitive training on cognitive performance of 119 healthy older adults, aged 60–87 years. Participants were randomly allocated to a cognitive training group or to an active control group in a single-blind controlled two-group design. Before and after training interactive television cognitive performance was assessed on well validated tests of fluid, higher-order ability, and system usability was evaluated. The participants in the cognitive training group completed a television-based cognitive training programme, while the participants in the active control group completed a TV-based programme of personally benefiting activities. Significant improvements were observed in well validated working memory and executive function tasks in the cognitive training but not in the control group. None of the groups showed statistically significant improvement in life satisfaction score. Participants' reports of “adequate” to “high” system usability testify to the successful development and implementation of the interactive television-based system and compliant cognitive training contents. The study demonstrates that cognitive training delivered by means of an interactive television system can generate genuine cognitive benefits in users and these are measurable using well-validated cognitive tests. Thus, older adults who cannot use or afford a computer can easily use digital interactive television to benefit from advanced software applications designed to train cognition. PMID:24992187

The triel bond: a potential force for tuning anion-π interactions

NASA Astrophysics Data System (ADS)

Esrafili, Mehdi D.; Mousavian, Parisasadat

2018-02-01

Using ab-initio calculations, the mutual influence between anion-π and B···N or B···C triel bond interactions is investigated in some model complexes. The properties of these complexes are studied by molecular electrostatic potential, noncovalent interaction index, quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) analyses. According to the results, the formation of B···N or B···C triel bond interactions in the multi-component systems makes a significant shortening of anion-π distance. Such remarkable variation in the anion-π distances has not been reported previously. The strengthening of the anion-π bonding in the multi-component systems depend significantly on the nature of the anion, and it becomes larger in the order Br- > Cl- > F-. The parameters derived from the QTAIM and NBO methodologies are used to study the mechanism of the cooperativity between the anion-π and triel bond interactions in the multi-component complexes.

Towards Co-Engineering Communicating Autonomous Cyber-Physical Systems

NASA Technical Reports Server (NTRS)

Bujorianu, Marius C.; Bujorianu, Manuela L.

2009-01-01

In this paper, we sketch a framework for interdisciplinary modeling of space systems, by proposing a holistic view. We consider different system dimensions and their interaction. Specifically, we study the interactions between computation, physics, communication, uncertainty and autonomy. The most comprehensive computational paradigm that supports a holistic perspective on autonomous space systems is given by cyber-physical systems. For these, the state of art consists of collaborating multi-engineering efforts that prompt for an adequate formal foundation. To achieve this, we propose a leveraging of the traditional content of formal modeling by a co-engineering process.

Learner Interaction Patterns and Student Perceptions toward Using Selected Tools in an Online Course Management System

ERIC Educational Resources Information Center

Kuna, Aruna Sai

2012-01-01

The study identified the association between student interaction patterns and academic performance in online graduate courses delivered by the Department of Agricultural Education and Studies at Iowa State University. In addition, the study investigated which online course tools were perceived by students to be most useful in learning. The study…

Direct and indirect impacts of crop-livestock organization on mixed crop-livestock systems sustainability: a model-based study.

PubMed

Sneessens, I; Veysset, P; Benoit, M; Lamadon, A; Brunschwig, G

2016-11-01

Crop-livestock production is claimed more sustainable than specialized production systems. However, the presence of controversial studies suggests that there must be conditions of mixing crop and livestock productions to allow for higher sustainable performances. Whereas previous studies focused on the impact of crop-livestock interactions on performances, we posit here that crop-livestock organization is a key determinant of farming system sustainability. Crop-livestock organization refers to the percentage of the agricultural area that is dedicated to each production. Our objective is to investigate if crop-livestock organization has both a direct and an indirect impact on mixed crop-livestock (MC-L) sustainability. In that objective, we build a whole-farm model parametrized on representative French sheep and crop farming systems in plain areas (Vienne, France). This model permits simulating contrasted MC-L systems and their subsequent sustainability through the following indicators of performance: farm income, production, N balance, greenhouse gas (GHG) emissions (/kg product) and MJ consumption (/kg product). Two MC-L systems were simulated with contrasted crop-livestock organizations (MC20-L80: 20% of crops; MC80-L20: 80% of crops). A first scenario - constraining no crop-livestock interactions in both MC-L systems - permits highlighting that crop-livestock organization has a significant direct impact on performances that implies trade-offs between objectives of sustainability. Indeed, the MC80-L20 system is showing higher performances for farm income (+44%), livestock production (+18%) and crop GHG emissions (-14%) whereas the MC20-L80 system has a better N balance (-53%) and a lower livestock MJ consumption (-9%). A second scenario - allowing for crop-livestock interactions in both MC20-L80 and MC80-L20 systems - stated that crop-livestock organization has a significant indirect impact on performances. Indeed, even if crop-livestock interactions permit improving performances, crop-livestock organization influences the capacity of MC-L systems to benefit from crop-livestock interactions. As a consequence, we observed a decreasing performance trade-off between MC-L systems for farm income (-4%) and crop GHG emissions (-10%) whereas the gap increases for nitrogen balance (+23%), livestock production (+6%) - MJ consumption (+16%) - GHG emissions (+5%) and crop MJ consumption (+5%). However, the indirect impact of crop-livestock organization doesn't reverse the trend of trade-offs between objectives of sustainability determined by the direct impact of crop-livestock organization. As a conclusion, crop-livestock organization is a key factor that has to be taken into account when studying the sustainability of mixed crop-livestock systems.

MIMO model of an interacting series process for Robust MPC via System Identification.

PubMed

Wibowo, Tri Chandra S; Saad, Nordin

2010-07-01

This paper discusses the empirical modeling using system identification technique with a focus on an interacting series process. The study is carried out experimentally using a gaseous pilot plant as the process, in which the dynamic of such a plant exhibits the typical dynamic of an interacting series process. Three practical approaches are investigated and their performances are evaluated. The models developed are also examined in real-time implementation of a linear model predictive control. The selected model is able to reproduce the main dynamic characteristics of the plant in open-loop and produces zero steady-state errors in closed-loop control system. Several issues concerning the identification process and the construction of a MIMO state space model for a series interacting process are deliberated. 2010 ISA. Published by Elsevier Ltd. All rights reserved.

Dynamical system analysis for DBI dark energy interacting with dark matter

NASA Astrophysics Data System (ADS)

Mahata, Nilanjana; Chakraborty, Subenoy

2015-01-01

A dynamical system analysis related to Dirac-Born-Infeld (DBI) cosmological model has been investigated in this present work. For spatially flat FRW spacetime, the Einstein field equation for DBI scenario has been used to study the dynamics of DBI dark energy interacting with dark matter. The DBI dark energy model is considered as a scalar field with a nonstandard kinetic energy term. An interaction between the DBI dark energy and dark matter is considered through a phenomenological interaction between DBI scalar field and the dark matter fluid. The field equations are reduced to an autonomous dynamical system by a suitable redefinition of the basic variables. The potential of the DBI scalar field is assumed to be exponential. Finally, critical points are determined, their nature have been analyzed and corresponding cosmological scenario has been discussed.

Intermolecular symmetry-adapted perturbation theory study of large organic complexes.

PubMed

Heßelmann, Andreas; Korona, Tatiana

2014-09-07

Binding energies for the complexes of the S12L database by Grimme [Chem. Eur. J. 18, 9955 (2012)] were calculated using intermolecular symmetry-adapted perturbation theory combined with a density-functional theory description of the interacting molecules. The individual interaction energy decompositions revealed no particular change in the stabilisation pattern as compared to smaller dimer systems at equilibrium structures. This demonstrates that, to some extent, the qualitative description of the interaction of small dimer systems may be extrapolated to larger systems, a method that is widely used in force-fields in which the total interaction energy is decomposed into atom-atom contributions. A comparison of the binding energies with accurate experimental reference values from Grimme, the latter including thermodynamic corrections from semiempirical calculations, has shown a fairly good agreement to within the error range of the reference binding energies.

Is there a link between the hospital-acquired injurious fall rates in US acute care hospitals and these institutions' implementation levels of computerized systems?

PubMed

Tzeng, Huey-Ming; Hu, Hsou Mei; Yin, Chang-Yi

2011-12-01

Medicare no longer reimburses acute care hospitals for the costs of additional care required due to hospital-acquired injuries. Consequently, this study explored the effective computerized systems to inform practice for better interventions to reduce fall risk. It provided a correlation between type of computerized system and hospital-acquired injurious fall rates at acute care hospitals in California, Florida, and New York. It used multiple publicly available data sets, with the hospital as the unit of analysis. Descriptive and Pearson correlation analyses were used. The analysis included 462 hospitals. Significant correlations could be categorized into two groups: (1) meaningful computerized systems that were associated with lower injurious fall rates: the decision support systems for drug allergy alerts, drug-drug interaction alerts, and drug-laboratory interaction alerts; and (2) computerized systems that were associated with higher injurious fall rates: the decision support system for drug-drug interaction alerts and the computerized provider order entry system for radiology tests. Future research may include additional states, multiple years of data, and patient-level data to validate this study's findings. This effort may further inform policy makers and the public about effective clinical computerized systems provided to clinicians to improve their practice decisions and care outcomes.

A Molecular Dynamic Modeling of Hemoglobin-Hemoglobin Interactions

NASA Astrophysics Data System (ADS)

Wu, Tao; Yang, Ye; Sheldon Wang, X.; Cohen, Barry; Ge, Hongya

2010-05-01

In this paper, we present a study of hemoglobin-hemoglobin interaction with model reduction methods. We begin with a simple spring-mass system with given parameters (mass and stiffness). With this known system, we compare the mode superposition method with Singular Value Decomposition (SVD) based Principal Component Analysis (PCA). Through PCA we are able to recover the principal direction of this system, namely the model direction. This model direction will be matched with the eigenvector derived from mode superposition analysis. The same technique will be implemented in a much more complicated hemoglobin-hemoglobin molecule interaction model, in which thousands of atoms in hemoglobin molecules are coupled with tens of thousands of T3 water molecule models. In this model, complex inter-atomic and inter-molecular potentials are replaced by nonlinear springs. We employ the same method to get the most significant modes and their frequencies of this complex dynamical system. More complex physical phenomena can then be further studied by these coarse grained models.

The chemical basis for the origin of the genetic code and the process of protein synthesis

NASA Technical Reports Server (NTRS)

1981-01-01

The principles upon which the process of protein synthesis and the genetic code were established are elucidated. Extensive work on nuclear magnetic resonance studies of both monomermonomer and monoamino acid polynucleotide interactions is included. A new method of general utility for studying any amino acid interacting with any polynucleotide was developed. This system involves the use of methyl esters of amino acids interacting with polynucleotides.

A Coupled Modeling Framework of the Co-evolution of Humans and Water: Case Study of Tarim River Basin, Western China

NASA Astrophysics Data System (ADS)

Liu, D.; Tian, F.; Lin, M.; Sivapalan, M.

2014-12-01

The complex interactions and feedbacks between humans and water are very essential issues but are poorly understood in the newly proposed discipline of socio-hydrology (Sivapalan et al., 2012). An exploratory model with the appropriate level of simplification can be valuable to improve our understanding of the co-evolution and self-organization of socio-hydrological systems driven by interactions and feedbacks operating at different scales. In this study, a simple coupled modeling framework for socio-hydrology co-evolution is developed for the Tarim River Basin in Western China, and is used to illustrate the explanatory power of such a model. The study area is the mainstream of the Tarim River, which is divided into two modeling units. The socio-hydrological system is composed of four parts, i.e., social sub-system, economic sub-system, ecological sub-system, and hydrological sub-system. In each modeling unit, four coupled ordinary differential equations are used to simulate the dynamics of the social sub-system represented by human population, the economic sub-system represented by irrigated crop area, the ecological sub-system represented by natural vegetation cover and the hydrological sub-system represented by stream discharge. The coupling and feedback processes of the four dominant sub-systems (and correspondingly four state variables) are integrated into several internal system characteristics interactively and jointly determined by themselves and by other coupled systems. For example, the stream discharge is coupled to the irrigated crop area by the colonization rate and mortality rate of the irrigated crop area in the upper reach and the irrigated area is coupled to stream discharge through irrigation water consumption. The co-evolution of the Tarim socio-hydrological system is then analyzed within this modeling framework to gain insights into the overall system dynamics and its sensitivity to the external drivers and internal system variables. In the modeling framework, the state of each subsystem is holistically described by one state variable and the framework is flexible enough to comprise more processes and constitutive relationships if they are needed to illustrate the interaction and feedback mechanisms of the human-water system.

Curcumin as a clinically-promising anti-cancer agent: pharmacokinetics and drug interactions.

PubMed

Adiwidjaja, Jeffry; McLachlan, Andrew J; Boddy, Alan V

2017-09-01

Curcumin has been extensively studied for its anti-cancer properties. While a diverse array of in vitro and preclinical research support the prospect of curcumin use as an anti-cancer therapeutic, most human studies have failed to meet the intended clinical expectation. Poor systemic availability of orally-administered curcumin may account for this disparity. Areas covered: This descriptive review aims to concisely summarise available clinical studies investigating curcumin pharmacokinetics when administered in different formulations. A critical analysis of pharmacokinetic- and pharmacodynamic-based interactions of curcumin with concomitantly administered drugs is also provided. Expert opinion: The encouraging clinical results of curcumin administration are currently limited to people with colorectal cancer, given that sufficient curcumin concentrations persist in colonic mucosa. Higher parent curcumin systemic exposure, which can be achieved by several newer formulations, has important implications for optimal treatment of cancers other than those in gastrointestinal tract. Curcumin-drug pharmacokinetic interactions are also almost exclusively in the enterocytes, owing to extensive first pass metabolism and poor curcumin bioavailability. Greater scope of these interactions, i.e. modulation of the systemic elimination of co-administered drugs, may be expected from more-bioavailable curcumin formulations. Further studies are still warranted, especially with newer formulations to support the inclusion of curcumin in cancer therapy regimens.

Predictive Mechanisms Are Not Involved the Same Way during Human-Human vs. Human-Machine Interactions: A Review

PubMed Central

Sahaï, Aïsha; Pacherie, Elisabeth; Grynszpan, Ouriel; Berberian, Bruno

2017-01-01

Nowadays, interactions with others do not only involve human peers but also automated systems. Many studies suggest that the motor predictive systems that are engaged during action execution are also involved during joint actions with peers and during other human generated action observation. Indeed, the comparator model hypothesis suggests that the comparison between a predicted state and an estimated real state enables motor control, and by a similar functioning, understanding and anticipating observed actions. Such a mechanism allows making predictions about an ongoing action, and is essential to action regulation, especially during joint actions with peers. Interestingly, the same comparison process has been shown to be involved in the construction of an individual's sense of agency, both for self-generated and observed other human generated actions. However, the implication of such predictive mechanisms during interactions with machines is not consensual, probably due to the high heterogeneousness of the automata used in the experimentations, from very simplistic devices to full humanoid robots. The discrepancies that are observed during human/machine interactions could arise from the absence of action/observation matching abilities when interacting with traditional low-level automata. Consistently, the difficulties to build a joint agency with this kind of machines could stem from the same problem. In this context, we aim to review the studies investigating predictive mechanisms during social interactions with humans and with automated artificial systems. We will start by presenting human data that show the involvement of predictions in action control and in the sense of agency during social interactions. Thereafter, we will confront this literature with data from the robotic field. Finally, we will address the upcoming issues in the field of robotics related to automated systems aimed at acting as collaborative agents. PMID:29081744

Agent-based modeling of endotoxin-induced acute inflammatory response in human blood leukocytes.

PubMed

Dong, Xu; Foteinou, Panagiota T; Calvano, Steven E; Lowry, Stephen F; Androulakis, Ioannis P

2010-02-18

Inflammation is a highly complex biological response evoked by many stimuli. A persistent challenge in modeling this dynamic process has been the (nonlinear) nature of the response that precludes the single-variable assumption. Systems-based approaches offer a promising possibility for understanding inflammation in its homeostatic context. In order to study the underlying complexity of the acute inflammatory response, an agent-based framework is developed that models the emerging host response as the outcome of orchestrated interactions associated with intricate signaling cascades and intercellular immune system interactions. An agent-based modeling (ABM) framework is proposed to study the nonlinear dynamics of acute human inflammation. The model is implemented using NetLogo software. Interacting agents involve either inflammation-specific molecules or cells essential for the propagation of the inflammatory reaction across the system. Spatial orientation of molecule interactions involved in signaling cascades coupled with the cellular heterogeneity are further taken into account. The proposed in silico model is evaluated through its ability to successfully reproduce a self-limited inflammatory response as well as a series of scenarios indicative of the nonlinear dynamics of the response. Such scenarios involve either a persistent (non)infectious response or innate immune tolerance and potentiation effects followed by perturbations in intracellular signaling molecules and cascades. The ABM framework developed in this study provides insight on the stochastic interactions of the mediators involved in the propagation of endotoxin signaling at the cellular response level. The simulation results are in accordance with our prior research effort associated with the development of deterministic human inflammation models that include transcriptional dynamics, signaling, and physiological components. The hypothetical scenarios explored in this study would potentially improve our understanding of how manipulating the behavior of the molecular species could manifest into emergent behavior of the overall system.

Interaction of N-vortex structures in a continuum, including atmosphere, hydrosphere and plasma

NASA Astrophysics Data System (ADS)

Belashov, Vasily Yu.

2017-10-01

The results of analysis and numerical simulation of evolution and interaction of the N-vortex structures of various configuration and different vorticities in the continuum including atmosphere, hydrosphere and plasma are presented. It is found that in dependence on initial conditions the regimes of weak interaction with quasi-stationary evolution and active interaction with the "phase intermixing", when the evolution can lead to formation of complex forms of vorticity regions, are realized in the N-vortex systems. For the 2-vortex interaction the generalized critical parameter determining qualitative character of interaction of vortices is introduced. It is shown that for given initial conditions its value divides modes of active interaction and quasi-stationary evolution. The results of simulation of evolution and interaction of the two-dimensional and three-dimensional vortex structures, including such phenomena as dynamics of the atmospheric synoptic vortices of cyclonic types and tornado, hydrodynamic 4-vortex interaction and also interaction in the systems of a type of "hydrodynamic vortex - dust particles" are presented. The applications of undertaken approach to the problems of such plasma systems as streams of charged particles in a uniform magnetic field B and plasma clouds in the ionosphere are considered. It is shown that the results obtained have obvious applications in studies of the dynamics of the vortex structures dynamics in atmosphere, hydrosphere and plasma.

Assessment of interactions of efavirenz solid drug nanoparticles with human immunological and haematological systems.

PubMed

Liptrott, Neill J; Giardiello, Marco; McDonald, Tom O; Rannard, Steve P; Owen, Andrew

2018-03-15

Recent work has developed solid drug nanoparticles (SDNs) of efavirenz that have been demonstrated, preclinically, improved oral bioavailability and the potential to enable up to a 50% dose reduction, and is currently being studied in a healthy volunteer clinical trial. Other SDN formulations are being studied for parenteral administration, either as intramuscular long-acting formulations, or for direct administration intravenously. The interaction of nanoparticles with the immunological and haematological systems can be a major barrier to successful translation but has been understudied for SDN formulations. Here we have conducted a preclinical evaluation of efavirenz SDN to assess their potential interaction with these systems. Platelet aggregation and activation, plasma coagulation, haemolysis, complement activation, T cell functionality and phenotype, monocyte derived macrophage functionality, and NK cell function were assessed in primary healthy volunteer samples treated with either aqueous efavirenz or efavirenz SDN. Efavirenz SDNs were shown not to interfere with any of the systems studied in terms of immunostimulation nor immunosuppression. Although efavirenz aqueous solution was shown to cause significant haemolysis ex vivo, efavirenz SDNs did not. No other interaction with haematological systems was observed. Efavirenz SDNs have been demonstrated to be immunologically and haematologically inert in the utilised assays. Taken collectively, along with the recent observation that lopinavir SDN formulations did not impact immunological responses, these data indicate that this type of nanoformulation does not elicit immunological consequences seen with other types of nanomaterial. The methodologies presented here provide a framework for pre-emptive preclinical characterisation of nanoparticle safety.

Understanding quantum work in a quantum many-body system.

PubMed

Wang, Qian; Quan, H T

2017-03-01

Based on previous studies in a single-particle system in both the integrable [Jarzynski, Quan, and Rahav, Phys. Rev. X 5, 031038 (2015)2160-330810.1103/PhysRevX.5.031038] and the chaotic systems [Zhu, Gong, Wu, and Quan, Phys. Rev. E 93, 062108 (2016)1539-375510.1103/PhysRevE.93.062108], we study the the correspondence principle between quantum and classical work distributions in a quantum many-body system. Even though the interaction and the indistinguishability of identical particles increase the complexity of the system, we find that for a quantum many-body system the quantum work distribution still converges to its classical counterpart in the semiclassical limit. Our results imply that there exists a correspondence principle between quantum and classical work distributions in an interacting quantum many-body system, especially in the large particle number limit, and further justify the definition of quantum work via two-point energy measurements in quantum many-body systems.

Quantum heat transport of a two-qubit system: Interplay between system-bath coherence and qubit-qubit coherence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kato, Akihito, E-mail: kato@kuchem.kyoto-u.ac.jp; Tanimura, Yoshitaka, E-mail: tanimura@kuchem.kyoto-u.ac.jp

2015-08-14

We consider a system consisting of two interacting qubits that are individually coupled to separate heat baths at different temperatures. The quantum effects in heat transport are investigated in a numerically rigorous manner with a hierarchial equations of motion (HEOM) approach for non-perturbative and non-Markovian system-bath coupling cases under non-equilibrium steady-state conditions. For a weak interqubit interaction, the total system is regarded as two individually thermostatted systems, whereas for a strong interqubit interaction, the two-qubit system is regarded as a single system coupled to two baths. The roles of quantum coherence (or entanglement) between the two qubits (q-q coherence) andmore » between the qubit and bath (q-b coherence) are studied through the heat current calculated for various strengths of the system-bath coupling and interqubit coupling for high and low temperatures. The same current is also studied using the time convolutionless (TCL) Redfield equation and using an expression derived from the Fermi golden rule (FGR). We find that the HEOM results exhibit turnover behavior of the heat current as a function of the system-bath coupling strength for all values of the interqubit coupling strength, while the results obtained with the TCL and FGR approaches do not exhibit such behavior, because they do not possess the capability of treating the q-b and q-q coherences. The maximum current is obtained in the case that the q-q coherence and q-b coherence are balanced in such a manner that coherence of the entire heat transport process is realized. We also find that the heat current does not follow Fourier’s law when the temperature difference is very large, due to the non-perturbative system-bath interactions.« less

Cognitive engineering models: A prerequisite to the design of human-computer interaction in complex dynamic systems

NASA Technical Reports Server (NTRS)

Mitchell, Christine M.

1993-01-01

This chapter examines a class of human-computer interaction applications, specifically the design of human-computer interaction for the operators of complex systems. Such systems include space systems (e.g., manned systems such as the Shuttle or space station, and unmanned systems such as NASA scientific satellites), aviation systems (e.g., the flight deck of 'glass cockpit' airplanes or air traffic control) and industrial systems (e.g., power plants, telephone networks, and sophisticated, e.g., 'lights out,' manufacturing facilities). The main body of human-computer interaction (HCI) research complements but does not directly address the primary issues involved in human-computer interaction design for operators of complex systems. Interfaces to complex systems are somewhat special. The 'user' in such systems - i.e., the human operator responsible for safe and effective system operation - is highly skilled, someone who in human-machine systems engineering is sometimes characterized as 'well trained, well motivated'. The 'job' or task context is paramount and, thus, human-computer interaction is subordinate to human job interaction. The design of human interaction with complex systems, i.e., the design of human job interaction, is sometimes called cognitive engineering.

ξTauri: a unique laboratory to study the dynamic interaction in a compact hierarchical quadruple system

NASA Astrophysics Data System (ADS)

Nemravová, J. A.; Harmanec, P.; Brož, M.; Vokrouhlický, D.; Mourard, D.; Hummel, C. A.; Cameron, C.; Matthews, J. M.; Bolton, C. T.; Božić, H.; Chini, R.; Dembsky, T.; Engle, S.; Farrington, C.; Grunhut, J. H.; Guenther, D. B.; Guinan, E. F.; Korčáková, D.; Koubský, P.; Kříček, R.; Kuschnig, R.; Mayer, P.; McCook, G. P.; Moffat, A. F. J.; Nardetto, N.; Prša, A.; Ribeiro, J.; Rowe, J.; Rucinski, S.; Škoda, P.; Šlechta, M.; Tallon-Bosc, I.; Votruba, V.; Weiss, W. W.; Wolf, M.; Zasche, P.; Zavala, R. T.

2016-10-01

Context. Compact hierarchical systems are important because the effects caused by the dynamical interaction among its members occur ona human timescale. These interactions play a role in the formation of close binaries through Kozai cycles with tides. One such system is ξ Tauri: it has three hierarchical orbits: 7.14 d (eclipsing components Aa, Ab), 145 d (components Aa+Ab, B), and 51 yr (components Aa+Ab+B, C). Aims: We aim to obtain physical properties of the system and to study the dynamical interaction between its components. Methods: Our analysis is based on a large series of spectroscopic photometric (including space-borne) observations and long-baseline optical and infrared spectro-interferometric observations. We used two approaches to infer the system properties: a set of observation-specific models, where all components have elliptical trajectories, and an N-body model, which computes the trajectory of each component by integrating Newton's equations of motion. Results: The triple subsystem exhibits clear signs of dynamical interaction. The most pronounced are the advance of the apsidal line and eclipse-timing variations. We determined the geometry of all three orbits using both observation-specific and N-body models. The latter correctly accounted for observed effects of the dynamical interaction, predicted cyclic variations of orbital inclinations, and determined the sense of motion of all orbits. Using perturbation theory, we demonstrate that prominent secular and periodic dynamical effects are explainable with a quadrupole interaction. We constrained the basic properties of all components, especially of members of the inner triple subsystem and detected rapid low-amplitude light variations that we attribute to co-rotating surface structures of component B. We also estimated the radius of component B. Properties of component C remain uncertain because of its low relative luminosity. We provide an independent estimate of the distance to the system. Conclusions: The accuracy and consistency of our results make ξ Tau an excellent test bed for models of formation and evolution of hierarchical systems. Full Tables D.1-D.7 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/594/A55Based on data from the MOST satellite, a former Canadian Space Agency mission, jointly operated by Microsatellite Systems Canada Inc. (MSCI; formerly Dynacon Inc.), the University of Toronto Institute for Aerospace Studies and the University of British Columbia, with the assistance of the University of Vienna.

Initial Drug Dissolution from Amorphous Solid Dispersions Controlled by Polymer Dissolution and Drug-Polymer Interaction.

PubMed

Chen, Yuejie; Wang, Shujing; Wang, Shan; Liu, Chengyu; Su, Ching; Hageman, Michael; Hussain, Munir; Haskell, Roy; Stefanski, Kevin; Qian, Feng

2016-10-01

To identify the key formulation factors controlling the initial drug and polymer dissolution rates from an amorphous solid dispersion (ASD). Ketoconazole (KTZ) ASDs using PVP, PVP-VA, HMPC, or HPMC-AS as polymeric matrix were prepared. For each drug-polymer system, two types of formulations with the same composition were prepared: 1. Spray dried dispersion (SDD) that is homogenous at molecular level, 2. Physical blend of SDD (80% drug loading) and pure polymer (SDD-PB) that is homogenous only at powder level. Flory-Huggins interaction parameters (χ) between KTZ and the four polymers were obtained by Flory-Huggins model fitting. Solution (13)C NMR and FT-IR were conducted to investigate the specific drug-polymer interaction in the solution and solid state, respectively. Intrinsic dissolution of both the drug and the polymer from ASDs were studied using a Higuchi style intrinsic dissolution apparatus. PXRD and confocal Raman microscopy were used to confirm the absence of drug crystallinity on the tablet surface before and after dissolution study. In solid state, KTZ is completely miscible with PVP, PVP-VA, or HPMC-AS, demonstrated by the negative χ values of -0.36, -0.46, -1.68, respectively; while is poorly miscible with HPMC shown by a positive χ value of 0.23. According to solution (13)C NMR and FT-IR studies, KTZ interacts with HPMC-AS strongly through H-bonding and dipole induced interaction; with PVPs and PVP-VA moderately through dipole-induced interactions; and with HPMC weakly without detectable attractive interaction. Furthermore, the "apparent" strength of drug-polymer interaction, measured by the extent of peak shift on NMR or FT-IR spectra, increases with the increasing number of interacting drug-polymer pairs. For ASDs with the presence of considerable drug-polymer interactions, such as KTZ/PVPs, KTZ/PVP-VA, or KTZ /HPMC-AS systems, drug released at the same rate as the polymer when intimate drug-polymer mixing was ensured (i.e., the SDD systems); while drug released much slower than the polymer when molecular level mixing or drug-polymer interaction was absent (SDD-PB systems). For ASDs without drug-polymer interaction (i.e., KTZ/HPMC systems), the mixing homogeneity had little impact on the release rate of either the drug or the polymer thus SDD and SDD-PB demonstrated the same drug or polymer release rate, while the drug released slowly and independently of polymer release. The initial drug release from an ASD was controlled by 1) the polymer release rate; 2) the strength of drug-polymer interaction, including the intrinsic interaction caused by the chemistry of the drug and the polymer (measured by the χ value), as well as that the apparent interaction caused by the drug-polymer ratio (measure by the extent of peak shift on spectroscopic analysis); and 3) the level of mixing homogeneity between the drug and polymer. In summary, the selection of polymer, drug-polymer ratio, and ASD processing conditions have profound impacts on the dissolution behavior of ASDs. Graphical Abstract Relationship between initial drug and polymer dissolution rates from amorphous solid dispersions with different mixing uniformity and drug-polymer interactions.

Rape Survivors' Agency within the Legal and Medical Systems

ERIC Educational Resources Information Center

Greeson, Megan R.; Campbell, Rebecca

2011-01-01

Many rape survivors seek help from the legal and medical systems post-assault. Previous studies have examined how social system personnel treat survivors, but less attention has been paid to how survivors attempt to shape their interactions with these systems. The purpose of this qualitative study was to examine rape survivors' agency--the active…

Message frames interact with motivational systems to determine depth of message processing.

PubMed

Shen, Lijiang; Dillard, James Price

2009-09-01

Although several theoretical perspectives predict that negatively framed messages will be processed more deeply than positively framed messages, a recent meta-analysis found no such difference. In this article, the authors explore 2 explanations for this inconsistency. One possibility is methodological: the statistics used in the primary studies underestimated framing effects on depth of message processing because the data were maldistributed. The other is theoretical: the absence of a main effect is veridical, but framing interacts with individual differences that predispose individuals to greater or lesser depth of processing. Data from 2 experiments (Ns = 286 and 252) were analyzed via tobit regression, a technique designed to overcome the limitations of maldistributed data. One study showed the predicted main effect for framing, but the other did not. Both studies showed the anticipated interaction: Depth of processing correlated positively with a measure of the behavioral activation system in the advantage framing condition, whereas depth of processing correlated positively with the behavioral inhibition system in the disadvantage framing condition.

An Approach to the Study of the Interactions between Ellagitannins and Oxygen during Oak Wood Aging.

PubMed

García-Estévez, Ignacio; Alcalde-Eon, Cristina; Martínez-Gil, Ana María; Rivas-Gonzalo, Julián C; Escribano-Bailón, M Teresa; Nevares, Ignacio; Del Alamo-Sanza, María

2017-08-09

During the aging of red wine in oak wood barrels, or in alternative aging systems, interactions between the compounds released from wood, the compounds of the wine, and oxygen can take place. The main objective of the present work was to study oxygen-ellagitannin interactions by monitoring their levels in three model systems, all containing the same amounts of French oak chips and differing only in the oxygen content: total absence, only the oxygen released from the chips, and air-saturated (model systems F, OW, and OS, respectively). This study has highlighted the influence of oxygen in the ellagitannins' evolution and the relevance of the oxygen trapped into the oak chips, reporting for the first time the kinetics of oxygen release to the model wine. Furthermore, the indirect contribution of oxygen to the ellagitannins' disappearance by boosting autoxidative reactions has also been pointed out. Vescalagin seems to be the ellagitannin most affected by the initial oxygen levels.

The Automation-by-Expertise-by-Training Interaction.

PubMed

Strauch, Barry

2017-03-01

I introduce the automation-by-expertise-by-training interaction in automated systems and discuss its influence on operator performance. Transportation accidents that, across a 30-year interval demonstrated identical automation-related operator errors, suggest a need to reexamine traditional views of automation. I review accident investigation reports, regulator studies, and literature on human computer interaction, expertise, and training and discuss how failing to attend to the interaction of automation, expertise level, and training has enabled operators to commit identical automation-related errors. Automated systems continue to provide capabilities exceeding operators' need for effective system operation and provide interfaces that can hinder, rather than enhance, operator automation-related situation awareness. Because of limitations in time and resources, training programs do not provide operators the expertise needed to effectively operate these automated systems, requiring them to obtain the expertise ad hoc during system operations. As a result, many do not acquire necessary automation-related system expertise. Integrating automation with expected operator expertise levels, and within training programs that provide operators the necessary automation expertise, can reduce opportunities for automation-related operator errors. Research to address the automation-by-expertise-by-training interaction is needed. However, such research must meet challenges inherent to examining realistic sociotechnical system automation features with representative samples of operators, perhaps by using observational and ethnographic research. Research in this domain should improve the integration of design and training and, it is hoped, enhance operator performance.

Potential drug-drug interactions between anti-cancer agents and community pharmacy dispensed drugs.

PubMed

Voll, Marsha L; Yap, Kim D; Terpstra, Wim E; Crul, Mirjam

2010-10-01

To identify the prevalence of potential drug-drug interactions between hospital pharmacy dispensed anti-cancer agents and community pharmacy dispensed drugs. A retrospective cohort study was conducted on the haematology/oncology department of the internal medicine ward in a large teaching hospital in Amsterdam, the Netherlands. Prescription data from the last 100 patients treated with anti-cancer agents were obtained from Paracelsus, the chemotherapy prescribing system in the hospital. The community pharmacy dispensed drugs of these patients were obtained by using OZIS, a system that allows regionally linked pharmacies to call up active medication on any patient. Both medication lists were manually screened for potential drug-drug interactions by using several information sources on interactions, e.g. Pubmed, the Flockhart P450 table, Micromedex and Dutch reference books. Prevalence of potential drug-drug interactions between anti-cancer agents provided by the hospital pharmacy and drugs dispensed by the community pharmacy. Ninety-one patients were included in the study. A total of 31 potential drug-drug interactions were found in 16 patients, of which 15 interactions were clinically relevant and would have required an intervention. Of these interactions 1 had a level of severity ≥ D, meaning the potential drug-drug interaction could lead to long lasting or permanent damage, or even death. The majority of the interactions requiring an intervention (67%) had a considerable level of evidence (≥ 2) and were based on well-documented case reports or controlled interaction studies. Most of the potential drug-drug interactions involved the antiretroviral drugs (40%), proton pump inhibitors (20%) and antibiotics (20%). The anti-cancer drug most involved in the drug-drug interactions is methotrexate (33%). This study reveals a high prevalence of potential drug-drug interactions between anti-cancer agents provided by the hospital pharmacy and drugs dispensed by the community pharmacy. It shows us there is need for an optimal medication surveillance mechanism to detect potential drug-drug interactions between these two groups of medication, especially because of the high toxicity of anticancer drugs and thus the severe consequences these interactions can have for the patient.

Contact angle of sessile drops in Lennard-Jones systems.

PubMed

Becker, Stefan; Urbassek, Herbert M; Horsch, Martin; Hasse, Hans

2014-11-18

Molecular dynamics simulations are used for studying the contact angle of nanoscale sessile drops on a planar solid wall in a system interacting via the truncated and shifted Lennard-Jones potential. The entire range between total wetting and dewetting is investigated by varying the solid-fluid dispersive interaction energy. The temperature is varied between the triple point and the critical temperature. A correlation is obtained for the contact angle in dependence of the temperature and the dispersive interaction energy. Size effects are studied by varying the number of fluid particles at otherwise constant conditions, using up to 150,000 particles. For particle numbers below 10,000, a decrease of the contact angle is found. This is attributed to a dependence of the solid-liquid surface tension on the droplet size. A convergence to a constant contact angle is observed for larger system sizes. The influence of the wall model is studied by varying the density of the wall. The effective solid-fluid dispersive interaction energy at a contact angle of θ = 90° is found to be independent of temperature and to decrease linearly with the solid density. A correlation is developed that describes the contact angle as a function of the dispersive interaction, the temperature, and the solid density. The density profile of the sessile drop and the surrounding vapor phase is described by a correlation combining a sigmoidal function and an oscillation term.

Coupling functions: Universal insights into dynamical interaction mechanisms

NASA Astrophysics Data System (ADS)

Stankovski, Tomislav; Pereira, Tiago; McClintock, Peter V. E.; Stefanovska, Aneta

2017-10-01

The dynamical systems found in nature are rarely isolated. Instead they interact and influence each other. The coupling functions that connect them contain detailed information about the functional mechanisms underlying the interactions and prescribe the physical rule specifying how an interaction occurs. A coherent and comprehensive review is presented encompassing the rapid progress made recently in the analysis, understanding, and applications of coupling functions. The basic concepts and characteristics of coupling functions are presented through demonstrative examples of different domains, revealing the mechanisms and emphasizing their multivariate nature. The theory of coupling functions is discussed through gradually increasing complexity from strong and weak interactions to globally coupled systems and networks. A variety of methods that have been developed for the detection and reconstruction of coupling functions from measured data is described. These methods are based on different statistical techniques for dynamical inference. Stemming from physics, such methods are being applied in diverse areas of science and technology, including chemistry, biology, physiology, neuroscience, social sciences, mechanics, and secure communications. This breadth of application illustrates the universality of coupling functions for studying the interaction mechanisms of coupled dynamical systems.

Tuning antiferromagnetic exchange interaction for spontaneous exchange bias in MnNiSnSi system

NASA Astrophysics Data System (ADS)

Jia, Liyun; Shen, Jianlei; Li, Mengmeng; Wang, Xi; Ma, Li; Zhen, Congmian; Hou, Denglu; Liu, Enke; Wang, Wenhong; Wu, Guangheng

2017-12-01

Based on almost all the data from the literature on spontaneous exchange bias (SEB), it is expected that the system will show SEB if it meets two conditions simultaneously: (i) there are the coexistence and competition of antiferromagnetic (AFM) and ferromagnetic (FM) interactions and (ii) AFM interaction should dominate but not be too strong in this competition. In order to verify this view, a systematic study on SEB has been performed in this work. Mn50Ni40Sn10 with strong FM interaction and without SEB is chosen as the mother composition, and the negative chemical pressure is introduced by the substitution of Sn by Si to enhance AFM interaction. It is found that a long-range FM ordering window is closed, and a long-range AFM ordering window is opened. As a result, SEB is triggered and a continuous tuning of the spontaneous exchange bias field (HSEB) from 0 Oe to 1300 Oe has been realized in a Mn50Ni40Sn10-xSix system by the enhanced AFM interaction.

Effect of P T symmetry on nonlinear waves for three-wave interaction models in the quadratic nonlinear media

NASA Astrophysics Data System (ADS)

Shen, Yujia; Wen, Zichao; Yan, Zhenya; Hang, Chao

2018-04-01

We study the three-wave interaction that couples an electromagnetic pump wave to two frequency down-converted daughter waves in a quadratic optical crystal and P T -symmetric potentials. P T symmetric potentials are shown to modulate stably nonlinear modes in two kinds of three-wave interaction models. The first one is a spatially extended three-wave interaction system with odd gain-and-loss distribution in the channel. Modulated by the P T -symmetric single-well or multi-well Scarf-II potentials, the system is numerically shown to possess stable soliton solutions. Via adiabatical change of system parameters, numerical simulations for the excitation and evolution of nonlinear modes are also performed. The second one is a combination of P T -symmetric models which are coupled via three-wave interactions. Families of nonlinear modes are found with some particular choices of parameters. Stable and unstable nonlinear modes are shown in distinct families by means of numerical simulations. These results will be useful to further investigate nonlinear modes in three-wave interaction models.

Usability testing in medical informatics: cognitive approaches to evaluation of information systems and user interfaces.

PubMed Central

Kushniruk, A. W.; Patel, V. L.; Cimino, J. J.

1997-01-01

This paper describes an approach to the evaluation of health care information technologies based on usability engineering and a methodological framework from the study of medical cognition. The approach involves collection of a rich set of data including video recording of health care workers as they interact with systems, such as computerized patient records and decision support tools. The methodology can be applied in the laboratory setting, typically involving subjects "thinking aloud" as they interact with a system. A similar approach to data collection and analysis can also be extended to study of computer systems in the "live" environment of hospital clinics. Our approach is also influenced from work in the area of cognitive task analysis, which aims to characterize the decision making and reasoning of subjects of varied levels of expertise as they interact with information technology in carrying out representative tasks. The stages involved in conducting cognitively-based usability analyses are detailed and the application of such analysis in the iterative process of system and interface development is discussed. PMID:9357620

Frequency modulation atomic force microscopy: a dynamic measurement technique for biological systems

NASA Astrophysics Data System (ADS)

Higgins, Michael J.; Riener, Christian K.; Uchihashi, Takayuki; Sader, John E.; McKendry, Rachel; Jarvis, Suzanne P.

2005-03-01

Frequency modulation atomic force microscopy (FM-AFM) has been modified to operate in a liquid environment within an atomic force microscope specifically designed for investigating biological samples. We demonstrate the applicability of FM-AFM to biological samples using the spectroscopy mode to measure the unbinding forces of a single receptor-ligand (biotin-avidin) interaction. We show that quantitative adhesion force measurements can only be obtained provided certain modifications are made to the existing theory, which is used to convert the detected frequency shifts to an interaction force. Quantitative force measurements revealed that the unbinding forces for the biotin-avidin interaction were greater than those reported in previous studies. This finding was due to the use of high average tip velocities, which were calculated to be two orders of magnitude greater than those typically used in unbinding receptor-ligand experiments. This study therefore highlights the potential use of FM-AFM to study a range of biological systems, including living cells and/or single biomolecule interactions.

Assessing preschoolers interactive behaviour: A validation study of the "Coding System for Mother-Child Interaction".

PubMed

Baiao, R; Baptista, J; Carneiro, A; Pinto, R; Toscano, C; Fearon, P; Soares, I; Mesquita, A R

2018-07-01

The preschool years are a period of great developmental achievements, which impact critically on a child's interactive skills. Having valid and reliable measures to assess interactive behaviour at this stage is therefore crucial. The aim of this study was to describe the adaptation and validation of the child coding of the Coding System for Mother-Child Interactions and discuss its applications and implications in future research and practice. Two hundred twenty Portuguese preschoolers and their mothers were videotaped during a structured task. Child and mother interactive behaviours were coded based on the task. Maternal reports on the child's temperament and emotional and behaviour problems were also collected, along with family psychosocial information. Interrater agreement was confirmed. The use of child Cooperation, Enthusiasm, and Negativity as subscales was supported by their correlations across tasks. Moreover, these subscales were correlated with each other, which supports the use of a global child interactive behaviour score. Convergent validity with a measure of emotional and behavioural problems (Child Behaviour Checklist 1 ½-5) was established, as well as divergent validity with a measure of temperament (Children's Behaviour Questionnaire-Short Form). Regarding associations with family variables, child interactive behaviour was only associated with maternal behaviour. Findings suggest that this coding system is a valid and reliable measure for assessing child interactive behaviour in preschool age children. It therefore represents an important alternative to this area of research and practice, with reduced costs and with more flexible training requirements. Attention should be given in future research to expanding this work to clinical populations and different age groups. © 2018 John Wiley & Sons Ltd.

Effect of attractive interactions between polymers on the effective force acting between colloids immersed in a polymer system: Analytic liquid-state theory.

PubMed

Chervanyov, A I

2016-12-28

By making use of the polymer reference interaction site model, we analytically study the effect of attractive interactions between polymers on the effective forces acting between colloids immersed in a polymer system. The performed theoretical analysis has no restrictions with respect to the polymer density and relative sizes of the colloids and polymers. The polymer mediated (PM) potential acting between colloids is shown to significantly depend on the strength and range of the polymer-polymer interactions. In the nano-particle limit, where the colloid radius is much smaller than the polymer gyration radius, the presence of attractive polymer-polymer interactions causes only quantitative changes to the PM potential. In the opposite limit of relatively large colloids, the polymer-polymer interactions revert the sign of the total effective force acting between colloids so that this force becomes attractive at sufficiently large polymer densities. With the objective to study an intricate interplay between the attractive PM forces and steric repulsion in different polymer density regimes, we calculate the second virial coefficient B of the total effective potential acting between colloids. The dependence of B on the polymer density is discussed in detail, revealing several novel features of the PM interactions caused by the presence of attractive polymer-polymer interactions.

Spontaneous collective synchronization in the Kuramoto model with additional non-local interactions

NASA Astrophysics Data System (ADS)

Gupta, Shamik

2017-10-01

In the context of the celebrated Kuramoto model of globally-coupled phase oscillators of distributed natural frequencies, which serves as a paradigm to investigate spontaneous collective synchronization in many-body interacting systems, we report on a very rich phase diagram in presence of thermal noise and an additional non-local interaction on a one-dimensional periodic lattice. Remarkably, the phase diagram involves both equilibrium and non-equilibrium phase transitions. In two contrasting limits of the dynamics, we obtain exact analytical results for the phase transitions. These two limits correspond to (i) the absence of thermal noise, when the dynamics reduces to that of a non-linear dynamical system, and (ii) the oscillators having the same natural frequency, when the dynamics becomes that of a statistical system in contact with a heat bath and relaxing to a statistical equilibrium state. In the former case, our exact analysis is based on the use of the so-called Ott-Antonsen ansatz to derive a reduced set of nonlinear partial differential equations for the macroscopic evolution of the system. Our results for the case of statistical equilibrium are on the other hand obtained by extending the well-known transfer matrix approach for nearest-neighbor Ising model to consider non-local interactions. The work offers a case study of exact analysis in many-body interacting systems. The results obtained underline the crucial role of additional non-local interactions in either destroying or enhancing the possibility of observing synchrony in mean-field systems exhibiting spontaneous synchronization.

Frustration and thermalization in an artificial magnetic quasicrystal

NASA Astrophysics Data System (ADS)

Shi, Dong; Budrikis, Zoe; Stein, Aaron; Morley, Sophie A.; Olmsted, Peter D.; Burnell, Gavin; Marrows, Christopher H.

2018-03-01

Artificial frustrated systems offer a playground to study the emergent properties of interacting systems. Most work to date has been on spatially periodic systems, known as artificial spin ices when the interacting elements are magnetic. Here we have studied artificial magnetic quasicrystals based on quasiperiodic Penrose tiling patterns of interacting nanomagnets. We construct a low-energy configuration from a step-by-step approach that we propose as a ground state. Topologically induced emergent frustration means that this configuration cannot be constructed from vertices in their ground states. It has two parts, a quasi-one-dimensional `skeleton' that spans the entire pattern and is capable of long-range order, surrounding `flippable' clusters of macrospins that lead to macroscopic degeneracy. Magnetic force microscopy imaging of Penrose tiling arrays revealed superdomains that are larger for more strongly coupled arrays, especially after annealing the array above its blocking temperature.

Frustration and thermalization in an artificial magnetic quasicrystal

DOE PAGES

Shi, Dong; Budrikis, Zoe; Stein, Aaron; ...

2017-12-11

Here, artificial frustrated systems offer a playground to study the emergent properties of interacting systems. Most work to date has been on spatially periodic systems, known as artificial spin ices when the interacting elements are magnetic. Here we have studied artificial magnetic quasicrystals based on quasiperiodic Penrose tiling patterns of interacting nanomagnets. We construct a low-energy configuration from a step-by-step approach that we propose as a ground state. Topologically induced emergent frustration means that this configuration cannot be constructed from vertices in their ground states. It has two parts, a quasi-one-dimensional ‘skeleton’ that spans the entire pattern and is capablemore » of long-range order, surrounding ‘flippable’ clusters of macrospins that lead to macroscopic degeneracy. Magnetic force microscopy imaging of Penrose tiling arrays revealed superdomains that are larger for more strongly coupled arrays, especially after annealing the array above its blocking temperature.« less

Frustration and thermalization in an artificial magnetic quasicrystal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, Dong; Budrikis, Zoe; Stein, Aaron

Here, artificial frustrated systems offer a playground to study the emergent properties of interacting systems. Most work to date has been on spatially periodic systems, known as artificial spin ices when the interacting elements are magnetic. Here we have studied artificial magnetic quasicrystals based on quasiperiodic Penrose tiling patterns of interacting nanomagnets. We construct a low-energy configuration from a step-by-step approach that we propose as a ground state. Topologically induced emergent frustration means that this configuration cannot be constructed from vertices in their ground states. It has two parts, a quasi-one-dimensional ‘skeleton’ that spans the entire pattern and is capablemore » of long-range order, surrounding ‘flippable’ clusters of macrospins that lead to macroscopic degeneracy. Magnetic force microscopy imaging of Penrose tiling arrays revealed superdomains that are larger for more strongly coupled arrays, especially after annealing the array above its blocking temperature.« less

The role of idiotypic interactions in the adaptive immune system: a belief-propagation approach

NASA Astrophysics Data System (ADS)

Bartolucci, Silvia; Mozeika, Alexander; Annibale, Alessia

2016-08-01

In this work we use belief-propagation techniques to study the equilibrium behaviour of a minimal model for the immune system comprising interacting T and B clones. We investigate the effect of the so-called idiotypic interactions among complementary B clones on the system’s activation. Our results show that B-B interactions increase the system’s resilience to noise, making clonal activation more stable, while increasing the cross-talk between different clones. We derive analytically the noise level at which a B clone gets activated, in the absence of cross-talk, and find that this increases with the strength of idiotypic interactions and with the number of T cells sending signals to the B clones. We also derive, analytically and numerically, via population dynamics, the critical line where clonal cross-talk arises. Our approach allows us to derive the B clone size distribution, which can be experimentally measured and gives important information about the adaptive immune system response to antigens and vaccination.

Detection of time delays and directional interactions based on time series from complex dynamical systems

NASA Astrophysics Data System (ADS)

Ma, Huanfei; Leng, Siyang; Tao, Chenyang; Ying, Xiong; Kurths, Jürgen; Lai, Ying-Cheng; Lin, Wei

2017-07-01

Data-based and model-free accurate identification of intrinsic time delays and directional interactions is an extremely challenging problem in complex dynamical systems and their networks reconstruction. A model-free method with new scores is proposed to be generally capable of detecting single, multiple, and distributed time delays. The method is applicable not only to mutually interacting dynamical variables but also to self-interacting variables in a time-delayed feedback loop. Validation of the method is carried out using physical, biological, and ecological models and real data sets. Especially, applying the method to air pollution data and hospital admission records of cardiovascular diseases in Hong Kong reveals the major air pollutants as a cause of the diseases and, more importantly, it uncovers a hidden time delay (about 30-40 days) in the causal influence that previous studies failed to detect. The proposed method is expected to be universally applicable to ascertaining and quantifying subtle interactions (e.g., causation) in complex systems arising from a broad range of disciplines.

A Protein Interaction Map of the Kalimantacin Biosynthesis Assembly Line

PubMed Central

Uytterhoeven, Birgit; Lathouwers, Thomas; Voet, Marleen; Michiels, Chris W.; Lavigne, Rob

2016-01-01

The antimicrobial secondary metabolite kalimantacin (also called batumin) is produced by a hybrid polyketide/non-ribosomal peptide system in Pseudomonas fluorescens BCCM_ID9359. In this study, the kalimantacin biosynthesis gene cluster is analyzed by yeast two-hybrid analysis, creating a protein–protein interaction map of the entire assembly line. In total, 28 potential interactions were identified, of which 13 could be confirmed further. These interactions include the dimerization of ketosynthase domains, a link between assembly line modules 9 and 10, and a specific interaction between the trans-acting enoyl reductase BatK and the carrier proteins of modules 8 and 10. These interactions reveal fundamental insight into the biosynthesis of secondary metabolites. This study is the first to reveal interactions in a complete biosynthetic pathway. Similar future studies could build a strong basis for engineering strategies in such clusters. PMID:27853452

Interaction entropy for protein-protein binding.

PubMed

Sun, Zhaoxi; Yan, Yu N; Yang, Maoyou; Zhang, John Z H

2017-03-28

Protein-protein interactions are at the heart of signal transduction and are central to the function of protein machine in biology. The highly specific protein-protein binding is quantitatively characterized by the binding free energy whose accurate calculation from the first principle is a grand challenge in computational biology. In this paper, we show how the interactionentropy approach, which was recently proposed for protein-ligand binding free energy calculation, can be applied to computing the entropic contribution to the protein-protein binding free energy. Explicit theoretical derivation of the interactionentropy approach for protein-protein interaction system is given in detail from the basic definition. Extensive computational studies for a dozen realistic protein-protein interaction systems are carried out using the present approach and comparisons of the results for these protein-protein systems with those from the standard normal mode method are presented. Analysis of the present method for application in protein-protein binding as well as the limitation of the method in numerical computation is discussed. Our study and analysis of the results provided useful information for extracting correct entropic contribution in protein-protein binding from molecular dynamics simulations.

Evaluation of dispersion interaction in glyoxal/silica organomineral system

NASA Astrophysics Data System (ADS)

Sokolova, Y. V.; Ayzenshtadt, A. M.; Strokova, V. V.

2017-11-01

It is proposed to use an organomineral additive based on glyoxal and saponite-containing waste in order to stabilize the road base. Preliminary studies have shown that soil modification with the organomineral additive with a quantitative ratio of components of glyoxal - 0.52 % and saponite-containing material - 17 % of sand mass increases its specific cohesion by 50 times. However, it is necessary to study the mechanism of interaction between the additive components and soil to optimize the composition and technology of additive introduction into the soil. This paper examines dispersion interaction in glyoxal/silica organomineral system. The Hamaker constant was chosen as a main parameter to evaluate dispersion interaction. This constant is determined based on the principle of measuring the contact angle of wetting with service fluids and calculating the dispersion component of material surface tension. The Hamaker constant in the glyoxal/silica organomineral system was 0.25·10-20 - 2.8·10-20 J at different glyoxal contents, while its maximum value was observed at 0.52 % glyoxal content. The results compared with literature and previously obtained data demonstrated good reproducibility.

RCS jet-flow field interaction effects on the aerodynamics of the space shuttle orbiter

NASA Technical Reports Server (NTRS)

Rausch, J. R.; Roberge, A. M.

1973-01-01

A study was conducted to determine the external effects caused by operation of the reaction control system during entry of the space shuttle orbiter. The effects of jet plume-external flow interactions were emphasized. Force data were obtained for the basic airframe characteristics plus induced effects when the reaction control system is operating. Resulting control amplification and/or coupling were derived and their effects on the aerodynamic stability and control of the orbiter and the reaction control system thrust were determined.

Exploring Middle School Teachers' Perceptions and Applications of a Site-Based, Technology-Related Professional Development Program Focused on Interactive Whiteboards and Classroom Response Systems

ERIC Educational Resources Information Center

Desai, Shreya J.

2012-01-01

This qualitative study examined five middle school teachers' perceptions of a site-based, technology-related professional development (TRPD) program focused on the interactive whiteboard (IWB) and the classroom response system (CRS) and the practices implemented in the teachers' classrooms as a result of participation in the TRPD…

The Design, Implementation, and Evaluation of a Digital Interactive Globe System Integrated into an Earth Science Course

ERIC Educational Resources Information Center

Liou, Wei-Kai; Bhagat, Kaushal Kumar; Chang, Chun-Yen

2018-01-01

The aim of this study is to design and implement a digital interactive globe system (DIGS), by integrating low-cost equipment to make DIGS cost-effective. DIGS includes a data processing unit, a wireless control unit, an image-capturing unit, a laser emission unit, and a three-dimensional hemispheric body-imaging screen. A quasi-experimental study…

The Monash University Interactive Simple Climate Model

NASA Astrophysics Data System (ADS)

Dommenget, D.

2013-12-01

The Monash university interactive simple climate model is a web-based interface that allows students and the general public to explore the physical simulation of the climate system with a real global climate model. It is based on the Globally Resolved Energy Balance (GREB) model, which is a climate model published by Dommenget and Floeter [2011] in the international peer review science journal Climate Dynamics. The model simulates most of the main physical processes in the climate system in a very simplistic way and therefore allows very fast and simple climate model simulations on a normal PC computer. Despite its simplicity the model simulates the climate response to external forcings, such as doubling of the CO2 concentrations very realistically (similar to state of the art climate models). The Monash simple climate model web-interface allows you to study the results of more than a 2000 different model experiments in an interactive way and it allows you to study a number of tutorials on the interactions of physical processes in the climate system and solve some puzzles. By switching OFF/ON physical processes you can deconstruct the climate and learn how all the different processes interact to generate the observed climate and how the processes interact to generate the IPCC predicted climate change for anthropogenic CO2 increase. The presentation will illustrate how this web-base tool works and what are the possibilities in teaching students with this tool are.

Disrupting the Networks of Cancer

PubMed Central

Camacho, Daniel F.; Pienta, Kenneth J.

2014-01-01

Ecosystems are interactive systems involving communities of species and their abiotic environment. Tumors are ecosystems in which cancer cells act as invasive species interacting with native host cell species in an established microenvironment within the larger host biosphere. At its heart, to study ecology is to study interconnectedness. In ecologic science, an ecologic network is a representation of the biotic interactions in an ecosystem in which species (nodes) are connected by pairwise interactions (links). Ecologic networks and signaling network models have been used to describe and compare the structures of ecosystems. It has been shown that disruption of ecologic networks through the loss of species or disruption of interactions between them can lead to the destruction of the ecosystem. Often, the destruction of a single node or link is not enough to disrupt the entire ecosystem. The more complex the network and its interactions, the more difficult it is to cause the extinction of a species, especially without leveraging other aspects of the ecosystem. Similarly, successful treatment of cancer with a single agent is rarely enough to cure a patient without strategically modifying the support systems conducive to survival of cancer. Cancer cells and the ecologic systems they reside in can be viewed as a series of nested networks. The most effective new paradigms for treatment will be developed through application of scaled network disruption. PMID:22442061

Disrupting the networks of cancer.

PubMed

Camacho, Daniel F; Pienta, Kenneth J

2012-05-15

Ecosystems are interactive systems involving communities of species and their abiotic environment. Tumors are ecosystems in which cancer cells act as invasive species interacting with native host cell species in an established microenvironment within the larger host biosphere. At its heart, to study ecology is to study interconnectedness. In ecologic science, an ecologic network is a representation of the biotic interactions in an ecosystem in which species (nodes) are connected by pairwise interactions (links). Ecologic networks and signaling network models have been used to describe and compare the structures of ecosystems. It has been shown that disruption of ecologic networks through the loss of species or disruption of interactions between them can lead to the destruction of the ecosystem. Often, the destruction of a single node or link is not enough to disrupt the entire ecosystem. The more complex the network and its interactions, the more difficult it is to cause the extinction of a species, especially without leveraging other aspects of the ecosystem. Similarly, successful treatment of cancer with a single agent is rarely enough to cure a patient without strategically modifying the support systems conducive to survival of cancer. Cancer cells and the ecologic systems they reside in can be viewed as a series of nested networks. The most effective new paradigms for treatment will be developed through application of scaled network disruption. ©2012 AACR.

Non-covalent interactions between thio-caffeine derivatives and water-soluble porphyrin in ethanol-water environment

NASA Astrophysics Data System (ADS)

Lipke, Agnieszka; Makarska-Bialokoz, Magdalena; Sierakowska, Arleta; Jasiewicz, Beata

2018-03-01

To determine the binding interactions and ability to form the non-covalent systems, the association process between 5,10,15,20-tetrakis[4-(trimethylammonio)phenyl]-21H,23H-porphine tetra-p-tosylate (H2TTMePP) and a series of five structurally diverse thio-caffeine analogues has been studied in ethanol and ethanol-water solutions, analyzing its absorption and steady-state fluorescence spectra. The porphyrin fluorescence lifetimes in the systems studied were established as well. During the titration with thio-caffeine compounds the slight bathochromic effect and considerable hypochromicity of the porphyrin Soret band maximum can be noted. The fluorescence quenching effect observed for interactions in H2TTMePP - thio-caffeine derivative systems, as well as the order of binding and fluorescence quenching constants (of 105-103 mol- 1) suggest the existence of the mechanism of static quenching due to the formation of non-covalent and non-fluorescent stacking complexes. In all the systems studied the phenomenon of the fractional accessibility of the fluorophore for the quencher was observed as well. Additionally, the specific binding interactions, due to the changes in reaction environment polarity, can be observed. It was found that thio-caffeine compounds can quench the porphyrin fluorescence according to the structure of thio-substituent in caffeine molecule. The obtained results can be potentially useful from scientific, therapeutic or environmental points of view.

CHITIN TRANSFORMATION AND PESTICIDE INTERACTIONS IN A SIMULATED AQUATIC MICROENVIRONMENTAL SYSTEM

EPA Science Inventory

Interactions between the structural animo-polysaccharide, chitin, and the organophosphate pesticide, azinphosmethyl (Guthion), have been studied in a controlled continuous flow-through microcosm. Pesticide-induced microbial population changes and increases in substrate utilizatio...

Stress Effects on Multiple Memory System Interactions

PubMed Central

Ness, Deborah; Calabrese, Pasquale

2016-01-01

Extensive behavioural, pharmacological, and neurological research reports stress effects on mammalian memory processes. While stress effects on memory quantity have been known for decades, the influence of stress on multiple memory systems and their distinct contributions to the learning process have only recently been described. In this paper, after summarizing the fundamental biological aspects of stress/emotional arousal and recapitulating functionally and anatomically distinct memory systems, we review recent animal and human studies exploring the effects of stress on multiple memory systems. Apart from discussing the interaction between distinct memory systems in stressful situations, we will also outline the fundamental role of the amygdala in mediating such stress effects. Additionally, based on the methods applied in the herein discussed studies, we will discuss how memory translates into behaviour. PMID:27034845

Three Dimensional Explicit Model for Cometary Tail Ions Interactions with Solar Wind

NASA Astrophysics Data System (ADS)

Al Bermani, M. J. F.; Alhamed, S. A.; Khalaf, S. Z.; Ali, H. Sh.; Selman, A. A.

2009-06-01

The different interactions between cometary tail and solar wind ions are studied in the present paper based on three-dimensional Lax explicit method. The model used in this research is based on the continuity equations describing the cometary tail-solar wind interactions. Three dimensional system was considered in this paper. Simulation of the physical system was achieved using computer code written using Matlab 7.0. The parameters studied here assumed Halley comet type and include the particle density rho, the particles velocity v, the magnetic field strength B, dynamic pressure p and internal energy E. The results of the present research showed that the interaction near the cometary nucleus is mainly affected by the new ions added to the plasma of the solar wind, which increases the average molecular weight and result in many unique characteristics of the cometary tail. These characteristics were explained in the presence of the IMF.

Quantifying electronic band interactions in van der Waals materials using angle-resolved reflected-electron spectroscopy.

PubMed

Jobst, Johannes; van der Torren, Alexander J H; Krasovskii, Eugene E; Balgley, Jesse; Dean, Cory R; Tromp, Rudolf M; van der Molen, Sense Jan

2016-11-29

High electron mobility is one of graphene's key properties, exploited for applications and fundamental research alike. Highest mobility values are found in heterostructures of graphene and hexagonal boron nitride, which consequently are widely used. However, surprisingly little is known about the interaction between the electronic states of these layered systems. Rather pragmatically, it is assumed that these do not couple significantly. Here we study the unoccupied band structure of graphite, boron nitride and their heterostructures using angle-resolved reflected-electron spectroscopy. We demonstrate that graphene and boron nitride bands do not interact over a wide energy range, despite their very similar dispersions. The method we use can be generally applied to study interactions in van der Waals systems, that is, artificial stacks of layered materials. With this we can quantitatively understand the 'chemistry of layers' by which novel materials are created via electronic coupling between the layers they are composed of.