Sample records for experimental approach exploitation

  1. Experimental Simulation of the Exploitation of Natural Gas Hydrate

    Directory of Open Access Journals (Sweden)

    Chang-Yu Sun


    Full Text Available Natural gas hydrates are cage-like crystalline compounds in which a large amount of methane is trapped within a crystal structure of water, forming solids at low temperature and high pressure. Natural gas hydrates are widely distributed in permafrost regions and offshore. It is estimated that the worldwide amounts of methane bound in gas hydrates are total twice the amount of carbon to be found in all known fossil fuels on earth. A proper understanding of the relevant exploitation technologies is then important for natural gas production applications. In this paper, the recent advances on the experimental simulation of natural gas hydrate exploitation using the major hydrate production technologies are summarized. In addition, the current situation of the industrial exploitation of natural gas hydrate is introduced, which are expected to be useful for establishing more safe and efficient gas production technologies.

  2. White Sharks Exploit the Sun during Predatory Approaches. (United States)

    Huveneers, Charlie; Holman, Dirk; Robbins, Rachel; Fox, Andrew; Endler, John A; Taylor, Alex H


    There is no conclusive evidence of any nonhuman animal using the sun as part of its predation strategy. Here, we show that the world's largest predatory fish-the white shark (Carcharodon carcharias)-exploits the sun when approaching baits by positioning the sun directly behind them. On sunny days, sharks reversed their direction of approach along an east-west axis from morning to afternoon but had uniformly distributed approach directions during overcast conditions. These results show that white sharks have sufficient behavioral flexibility to exploit fluctuating environmental features when predating. This sun-tracking predation strategy has a number of potential functional roles, including improvement of prey detection, avoidance of retinal overstimulation, and predator concealment.

  3. Experimental approaches and applications

    CERN Document Server

    Crasemann, Bernd


    Atomic Inner-Shell Processes, Volume II: Experimental Approaches and Applications focuses on the physics of atomic inner shells, with emphasis on experimental aspects including the use of radioactive atoms for studies of atomic transition probabilities. Surveys of modern techniques of electron and photon spectrometry are also presented, and selected practical applications of inner-shell processes are outlined. Comprised of six chapters, this volume begins with an overview of the general principles underlying the experimental techniques that make use of radioactive isotopes for inner-sh

  4. Simultaneously Exploiting Two Formulations: an Exact Benders Decomposition Approach

    DEFF Research Database (Denmark)

    Lusby, Richard Martin; Gamst, Mette; Spoorendonk, Simon

    . Furthermore, it proves the correctness of the procedure and considers how to include interesting extensions such as cutting planes and advanced branching strategies. Finally, we test and compare the performance of the proposed approach on publicly available instances of the Bin Packing problem. Compared......When modelling a given problem using linear programming techniques several possibilities often exist, and each results in a different mathematical formulation of the problem. Usually, advantages and disadvantages can be identified in any single formulation. In this paper we consider mixed integer...... linear programs and propose an approach based on Benders decomposition to exploit the advantages of two different formulations when solving a problem. We propose to apply Benders decomposition to a combined formulation,comprised of two separate formulations, augmented with linking constraints to ensure...

  5. Management an experimental approach. (United States)

    Reed, J C; Aspy, V H


    An experimental teaching procedure was devised and tested for integrating the nursing process, nursing care plans, the research process and management principals. The integration defined as the problem oriented process (POP) was tested with 16 students over two semesters. The results indicated that the POP was a successful integration that aided the student in "getting it all together." As one of the students put it: This experience will give future students, as it did me, a better understanding of how research is best utilized. The students can use almost all their past learning experiences, bringing it all together in one situation. He (the student) can use his communication skills to detect a problem, his research skills to design planned intervention and evaluation and his interpersonal skills to measure his effectiveness as a change agent. Finally, he can use his nursing skills and knowledge of pathophysiology in a setting most like what he will find upon graduation.

  6. Exploiting the Errors: A Simple Approach for Improved Volatility Forecasting

    DEFF Research Database (Denmark)

    Bollerslev, Tim; Patton, Andrew J.; Quaedvlieg, Rogier

    We propose a new family of easy-to-implement realized volatility based forecasting models. The models exploit the asymptotic theory for high-frequency realized volatility estimation to improve the accuracy of the forecasts. By allowing the parameters of the models to vary explicitly with the (est......We propose a new family of easy-to-implement realized volatility based forecasting models. The models exploit the asymptotic theory for high-frequency realized volatility estimation to improve the accuracy of the forecasts. By allowing the parameters of the models to vary explicitly...... with the (estimated) degree of measurement error, the models exhibit stronger persistence, and in turn generate more responsive forecasts, when the measurement error is relatively low. Implementing the new class of models for the S&P500 equity index and the individual constituents of the Dow Jones Industrial Average...

  7. Experimental design a chemometric approach

    CERN Document Server

    Deming, SN


    Now available in a paperback edition is a book which has been described as `` exceptionally lucid, easy-to-read presentation... would be an excellent addition to the collection of every analytical chemist. I recommend it with great enthusiasm.'' (Analytical Chemistry). Unlike most current textbooks, it approaches experimental design from the point of view of the experimenter, rather than that of the statistician. As the reviewer in `Analytical Chemistry' went on to say: ``Deming and Morgan should be given high praise for bringing the principles of experimental design to the level of the p

  8. An ontological approach for the exploitation of clinical data. (United States)

    Assélé Kama, Ariane; Choquet, Rémy; Mels, Giovanni; Daniel, Christel; Charlet, Jean; Jaulent, Marie-Christine


    Clinical data captured in hospital information systems may be unusable in their original format due to missing information or knowledge. The use of external resources (e.g. domain ontology) could be a way of dealing with this lack of knowledge. Our study thus aimed to develop a framework allowing a user to perform medical queries in the context of infectious diseases. By creating an interaction between a knowledge source and clinical data, using semantic and semantic web tools and methods, the users are able to perform queries on a database to obtain results about antibiotic resistance. This work has been performed in the context of the DebugIT European project that aims to control and monitor the antibioresistance growth via a semantic interoperability platform. The results obtained by the use of different semantic web tools were quantitatively evaluated by comparison of the number of results and the query execution time. We have compared our approach with classic business intelligence approaches in terms of usability and functionality.

  9. Stochastic control approaches for sensor management in search and exploitation (United States)

    Hitchings, Darin Chester

    Recent improvements in the capabilities of autonomous vehicles have motivated their increased use in such applications as defense, homeland security, environmental monitoring, and surveillance. To enhance performance in these applications, new algorithms are required to control teams of robots autonomously and through limited interactions with human operators. In this dissertation we develop new algorithms for control of robots performing information-seeking missions in unknown environments. These missions require robots to control their sensors in order to discover the presence of objects, keep track of the objects, and learn what these objects are, given a fixed sensing budget. Initially, we investigate control of multiple sensors, with a finite set of sensing options and finite-valued measurements, to locate and classify objects given a limited resource budget. The control problem is formulated as a Partially Observed Markov Decision Problem (POMDP), but its exact solution requires excessive computation. Under the assumption that sensor error statistics are independent and time-invariant, we develop a class of algorithms using Lagrangian Relaxation techniques to obtain optimal mixed strategies using performance bounds developed in previous research. We investigate alternative Receding Horizon (RH) controllers to convert the mixed strategies to feasible adaptive-sensing strategies and evaluate the relative performance of these controllers in simulation. The resulting controllers provide superior performance to alternative algorithms proposed in the literature and obtain solutions to large-scale POMDP problems several orders of magnitude faster than optimal Dynamic Programming (DP) approaches with comparable performance quality. We extend our results for finite action, finite measurement sensor control to scenarios with moving objects. We use Hidden Markov Models (HMMs) for the evolution of objects, according to the dynamics of a birth-death process. We develop a

  10. Design approaches to experimental mediation. (United States)

    Pirlott, Angela G; MacKinnon, David P


    Identifying causal mechanisms has become a cornerstone of experimental social psychology, and editors in top social psychology journals champion the use of mediation methods, particularly innovative ones when possible (e.g. Halberstadt, 2010, Smith, 2012). Commonly, studies in experimental social psychology randomly assign participants to levels of the independent variable and measure the mediating and dependent variables, and the mediator is assumed to causally affect the dependent variable. However, participants are not randomly assigned to levels of the mediating variable(s), i.e., the relationship between the mediating and dependent variables is correlational. Although researchers likely know that correlational studies pose a risk of confounding, this problem seems forgotten when thinking about experimental designs randomly assigning participants to levels of the independent variable and measuring the mediator (i.e., "measurement-of-mediation" designs). Experimentally manipulating the mediator provides an approach to solving these problems, yet these methods contain their own set of challenges (e.g., Bullock, Green, & Ha, 2010). We describe types of experimental manipulations targeting the mediator (manipulations demonstrating a causal effect of the mediator on the dependent variable and manipulations targeting the strength of the causal effect of the mediator) and types of experimental designs (double randomization, concurrent double randomization, and parallel), provide published examples of the designs, and discuss the strengths and challenges of each design. Therefore, the goals of this paper include providing a practical guide to manipulation-of-mediator designs in light of their challenges and encouraging researchers to use more rigorous approaches to mediation because manipulation-of-mediator designs strengthen the ability to infer causality of the mediating variable on the dependent variable.

  11. Parallel exploitation of a spatial-spectral classification approach for hyperspectral images on RVC-CAL (United States)

    Lazcano, R.; Madroñal, D.; Fabelo, H.; Ortega, S.; Salvador, R.; Callicó, G. M.; Juárez, E.; Sanz, C.


    Hyperspectral Imaging (HI) assembles high resolution spectral information from hundreds of narrow bands across the electromagnetic spectrum, thus generating 3D data cubes in which each pixel gathers the spectral information of the reflectance of every spatial pixel. As a result, each image is composed of large volumes of data, which turns its processing into a challenge, as performance requirements have been continuously tightened. For instance, new HI applications demand real-time responses. Hence, parallel processing becomes a necessity to achieve this requirement, so the intrinsic parallelism of the algorithms must be exploited. In this paper, a spatial-spectral classification approach has been implemented using a dataflow language known as RVCCAL. This language represents a system as a set of functional units, and its main advantage is that it simplifies the parallelization process by mapping the different blocks over different processing units. The spatial-spectral classification approach aims at refining the classification results previously obtained by using a K-Nearest Neighbors (KNN) filtering process, in which both the pixel spectral value and the spatial coordinates are considered. To do so, KNN needs two inputs: a one-band representation of the hyperspectral image and the classification results provided by a pixel-wise classifier. Thus, spatial-spectral classification algorithm is divided into three different stages: a Principal Component Analysis (PCA) algorithm for computing the one-band representation of the image, a Support Vector Machine (SVM) classifier, and the KNN-based filtering algorithm. The parallelization of these algorithms shows promising results in terms of computational time, as the mapping of them over different cores presents a speedup of 2.69x when using 3 cores. Consequently, experimental results demonstrate that real-time processing of hyperspectral images is achievable.

  12. Molecular approaches in experimental neuroimaging

    Energy Technology Data Exchange (ETDEWEB)

    Tavitian, B. [CEA Saclay, 91 - Gif sur Yvette (France)


    We quantified and compared six parameters (resolution, depth, sensitivity, portability, quantification and cost) of four molecular imaging techniques (MRI, optics, ultrasound and TEP), with the three types of electromagnetic radiation used in vivo (Frequencies (10{sup 6} to 10{sup 22} Hz), Photonic Energy (10{sup -4} to 10{sup 9} eV) and Wavelengths (10{sup -2} to 10{sup -15} m)). This form of molecular imaging demands the most sensitive technique available (Pl. 26-2 to 26-4). Four examples of experimental in vivo approaches on small animals are shown: molecular passage through the blood-brain barrier (endothelial cells, astrocytes and occludin, pharmacokinetics, studied with PET) (Pl. 2-5 to 2-11); imaging of receptors and ligands, especially peripheral benzodiazepine receptors (PBR) by PET and MRI in the rat (Pl. 2-12 to Pl. 2-15); neuro-pathology of neuro-degenerative and inflammatory diseases and stroke by PET and MRI in the rat (Pl. 2-16 to 2-17); and the study of responses to stimulation explored with in vivo imaging of calcium signals and their variations by photonic analysis, as on the scale of mitochondrial calcium (Pl.2-18 to Pl.2-22). (author)

  13. Investigating performance variability of processing, exploitation, and dissemination using a socio-technical systems analysis approach (United States)

    Danczyk, Jennifer; Wollocko, Arthur; Farry, Michael; Voshell, Martin


    Data collection processes supporting Intelligence, Surveillance, and Reconnaissance (ISR) missions have recently undergone a technological transition accomplished by investment in sensor platforms. Various agencies have made these investments to increase the resolution, duration, and quality of data collection, to provide more relevant and recent data to warfighters. However, while sensor improvements have increased the volume of high-resolution data, they often fail to improve situational awareness and actionable intelligence for the warfighter because it lacks efficient Processing, Exploitation, and Dissemination and filtering methods for mission-relevant information needs. The volume of collected ISR data often overwhelms manual and automated processes in modern analysis enterprises, resulting in underexploited data, insufficient, or lack of answers to information requests. The outcome is a significant breakdown in the analytical workflow. To cope with this data overload, many intelligence organizations have sought to re-organize their general staffing requirements and workflows to enhance team communication and coordination, with hopes of exploiting as much high-value data as possible and understanding the value of actionable intelligence well before its relevance has passed. Through this effort we have taken a scholarly approach to this problem by studying the evolution of Processing, Exploitation, and Dissemination, with a specific focus on the Army's most recent evolutions using the Functional Resonance Analysis Method. This method investigates socio-technical processes by analyzing their intended functions and aspects to determine performance variabilities. Gaps are identified and recommendations about force structure and future R and D priorities to increase the throughput of the intelligence enterprise are discussed.

  14. Science Academies' Refresher Course on Experimental Approaches ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 22; Issue 10. Science Academies' Refresher Course on Experimental Approaches to Molecular Microbiology and Cell Biology. Information and Announcements Volume 22 Issue 10 October 2017 pp 971-971 ...

  15. Geographically distributed Batch System as a Service: the INDIGO-DataCloud approach exploiting HTCondor (United States)

    Aiftimiei, D. C.; Antonacci, M.; Bagnasco, S.; Boccali, T.; Bucchi, R.; Caballer, M.; Costantini, A.; Donvito, G.; Gaido, L.; Italiano, A.; Michelotto, D.; Panella, M.; Salomoni, D.; Vallero, S.


    One of the challenges a scientific computing center has to face is to keep delivering well consolidated computational frameworks (i.e. the batch computing farm), while conforming to modern computing paradigms. The aim is to ease system administration at all levels (from hardware to applications) and to provide a smooth end-user experience. Within the INDIGO- DataCloud project, we adopt two different approaches to implement a PaaS-level, on-demand Batch Farm Service based on HTCondor and Mesos. In the first approach, described in this paper, the various HTCondor daemons are packaged inside pre-configured Docker images and deployed as Long Running Services through Marathon, profiting from its health checks and failover capabilities. In the second approach, we are going to implement an ad-hoc HTCondor framework for Mesos. Container-to-container communication and isolation have been addressed exploring a solution based on overlay networks (based on the Calico Project). Finally, we have studied the possibility to deploy an HTCondor cluster that spans over different sites, exploiting the Condor Connection Broker component, that allows communication across a private network boundary or firewall as in case of multi-site deployments. In this paper, we are going to describe and motivate our implementation choices and to show the results of the first tests performed.

  16. Towards a multi-scale approach for an Earth observation-based assessment of natural resource exploitation in conflict regions


    SCHOEPFER Elisabeth; Spröhnle, Kristin; Kranz, Olaf; Blaes, Xavier; KOLOMAZNIK Jan; Hilgert, Filip; BARTALOS Tomas; Kemper, Thomas


    The exploitation of resources, if not properly managed, can lead to spoiling natural habitats as well as to threatening people’s health, livelihoods and security. The paper discusses a multi-scale Earth observation-based approach to provide independent information related to exploitation activities of natural resources for countries which are experiencing armed conflict. The analyses are based on medium to very high spatial resolution optical satellite data. Object-based image analysis is use...

  17. Experimental design research approaches, perspectives, applications

    CERN Document Server

    Stanković, Tino; Štorga, Mario


    This book presents a new, multidisciplinary perspective on and paradigm for integrative experimental design research. It addresses various perspectives on methods, analysis and overall research approach, and how they can be synthesized to advance understanding of design. It explores the foundations of experimental approaches and their utility in this domain, and brings together analytical approaches to promote an integrated understanding. The book also investigates where these approaches lead to and how they link design research more fully with other disciplines (e.g. psychology, cognition, sociology, computer science, management). Above all, the book emphasizes the integrative nature of design research in terms of the methods, theories, and units of study—from the individual to the organizational level. Although this approach offers many advantages, it has inherently led to a situation in current research practice where methods are diverging and integration between individual, team and organizational under...

  18. Exploiting impedance shaping approaches to overcome force overshoots in delicate interaction tasks

    Directory of Open Access Journals (Sweden)

    Loris Roveda


    Full Text Available The aim of the presented article is to overcome the force overshoot issue in impedance based force tracking applications. Nowadays, light-weight manipulators are involved in high-accurate force control applications (such as polishing tasks, where the force overshoot issue is critical (i.e. damaging the component causing a production waste, exploiting the impedance control. Two main force tracking impedance control approaches are described in literature: (a set-point deformation and (b variable stiffness approaches. However, no contributions are directly related to the force overshoot issue. The presented article extends both such methodologies to analytically achieve the force overshoots avoidance in interaction tasks based on the on-line estimation of the interacting environment stiffness (available through an EKF. Both the proposed control algorithms allow to achieve a linear closed-loop dynamics for the coupled robot-environment system. Therefore, control gains can be analytically on-line calculated to achieve an over-damped closed-loop dynamics of the controlled coupled system. Control strategies have been validated in experiments, involving a KUKA LWR 4+. A probing task has been performed, representative of many industrial tasks (e.g. assembly tasks, in which a main force task direction is defined.

  19. Toward a Cooperative Experimental System Development Approach

    DEFF Research Database (Denmark)


    This chapter represents a step towards the establishment of a new system development approach, called Cooperative Experimental System Development (CESD). CESD seeks to overcome a number of limitations in existing approaches: specification oriented methods usually assume that system design can...... be based solely on observation and detached reflection; prototyping methods often have a narrow focus on the technical construction of various kinds of prototypes; Participatory Design techniques—including the Scandinavian Cooperative Design (CD) approaches—seldom go beyond the early analysis...

  20. Experimentally exploiting the violation of the Lagrange invariant for resolution improvement. (United States)

    Lai, Xiaomin; Xiao, Sheng; Guo, Yiming; Lv, Xiaohua; Zeng, Shaoqun


    It is experimentally demonstrated that even though the numerical aperture in the object space is fixed, the resolution of an imaging system still can be improved by adjusting the parameters in the image space. This strategy cannot be realized until the discovery of the violation of the Lagrange invariant in a kind of self-interference holography. With the violation, parameters in the image space can escape the constraint of the object space for resolution improvement. Experiments that directly confirm this new ability are implemented and results agree well with the theoretical prediction. Additionally, better performance on frequency recording and finer details beyond the diffraction limit have been recorded with this method.

  1. Exploration of Exploitation Approaches of European Projects on ICT and Foreign Language Learning: the CEFcult project case

    NARCIS (Netherlands)

    Rusman, Ellen; Rajagopal, Kamakshi; Stoyanov, Slavi; Van Maele, Jan


    Rusman, E., Rajagopal, K., Stoyanov, S., & Van Maele, J. (2011, 20 October). Exploration of Exploitation Approaches of European Projects on ICT and Foreign Language Learning: the CEFcult project case. Presentation at the 4th International Conference ICT for Language Learning, Florence, Italy.

  2. Exploration of Exploitation Approaches of European Projects on ICT and Foreign Language Learning: the CEFcult project case

    NARCIS (Netherlands)

    Rusman, Ellen; Rajagopal, Kamakshi; Stoyanov, Slavi; Van Maele, Jan


    Rusman, E., Rajagopal, K., Stoyanov, S., & Van Maele, J. (2011, 20-21 October). Exploration of Exploitation Approaches of European Projects on ICT and Foreign Language Learning: the CEFcult project case. Paper presented at the 4th International Conference ICT for Language Learning, Florence, Italy.

  3. Involving students in experimental design: three approaches. (United States)

    McNeal, A P; Silverthorn, D U; Stratton, D B


    Many faculty want to involve students more actively in laboratories and in experimental design. However, just "turning them loose in the lab" is time-consuming and can be frustrating for both students and faculty. We describe three different ways of providing structures for labs that require students to design their own experiments but guide the choices. One approach emphasizes invertebrate preparations and classic techniques that students can learn fairly easily. Students must read relevant primary literature and learn each technique in one week, and then design and carry out their own experiments in the next week. Another approach provides a "design framework" for the experiments so that all students are using the same technique and the same statistical comparisons, whereas their experimental questions differ widely. The third approach involves assigning the questions or problems but challenging students to design good protocols to answer these questions. In each case, there is a mixture of structure and freedom that works for the level of the students, the resources available, and our particular aims.

  4. Exploiting the potential of marine natural products: structure elucidation and metagenomic approaches to biotechnological production


    Della Sala, Gerardo


    Sponges represent the most prolific producers of novel marine bioactive secondary metabolites. In the last years, several drugs derived from marine natural products have appeared in the market, and others are in clinical trials. The aim of my research project was to exploit the unusual and often surprising chemistry of marine sponges, in the frame of the more general purpose of discovering and developing new drugs from natural products. The research work presented in this PhD Thesis was di...

  5. Spaceborne Lightcraft Applications—an Experimental Approach (United States)

    Scharring, Stefan; Eckel, Hans-Albert; Trommer, Jens; Röser, Hans-Peter; Eigenbrod, Christian


    An experimental approach is proposed for the near-term demonstration of space-borne laser propulsion. A feasibility study at the ZARM Drop Tower Bremen is planned. The facility provides microgravity conditions within a drop capsule for ˜9 seconds. An excimer laser is used for energy beaming operating at a wavelength of 248 nm with max. 500 mJ pulse energy and a repetition rate of 250 Hz. Within the drop capsule, free flights of a lightcraft are intended to be conducted in air as well as under vacuum conditions. Different propellants are reviewed regarding their features for propulsion with a UV laser. The scalability of previous ground-based flight experiments is discussed with respect to microgravity conditions and moderate pulse energies. Space logistic and sample return missions are discussed as possible applications.

  6. Capacity-Approaching Modulation Formats for Optical Transmission Systems: Signal shaping and advanced de/muxing for efficient resource exploitation

    DEFF Research Database (Denmark)

    Estaran Tolosa, Jose Manuel

    Aiming for efficient fiber-optic data transport, this thesis addresses three scenario-specific modulation and/or multiplexing techniques which, leveraging digital signal processing, can further exploit the available resources.The considered environments are: (i) (ultra) long-haul networks, where we...... essentials, signal attributes, and digital processing structures are discussed in detail; whereby we give grounds for their adoption into the respective contexts of the three proposed systems. Eventually, we conduct the corresponding experimental validations; overall proving their potential. The reported...

  7. Helix Nebula and CERN: A Symbiotic approach to exploiting commercial clouds

    CERN Document Server

    Barreiro Megino, Fernando Harald; Kucharczyk, Katarzyna; Medrano Llamas, Ramón; van der Ster, Daniel


    The recent paradigm shift toward cloud computing in IT, and general interest in "Big Data" in particular, have demonstrated that the computing requirements of HEP are no longer globally unique. Indeed, the CERN IT department and LHC experiments have already made significant R&D investments in delivering and exploiting cloud computing resources. While a number of technical evaluations of interesting commercial offerings from global IT enterprises have been performed by various physics labs, further technical, security, sociological, and legal issues need to be address before their large-scale adoption by the research community can be envisaged. Helix Nebula - the Science Cloud is an initiative that explores these questions by joining the forces of three European research institutes (CERN, ESA and EMBL) with leading European commercial IT enterprises. The goals of Helix Nebula are to establish a cloud platform federating multiple commercial cloud providers, along with new business models, which can sustain ...

  8. Conjugation of squalene to gemcitabine as unique approach exploiting endogenous lipoproteins for drug delivery (United States)

    Sobot, Dunja; Mura, Simona; Yesylevskyy, Semen O.; Dalbin, Laura; Cayre, Fanny; Bort, Guillaume; Mougin, Julie; Desmaële, Didier; Lepetre-Mouelhi, Sinda; Pieters, Grégory; Andreiuk, Bohdan; Klymchenko, Andrey S.; Paul, Jean-Louis; Ramseyer, Christophe; Couvreur, Patrick


    Once introduced in the organism, the interaction of nanoparticles with various biomolecules strongly impacts their fate. Here we show that nanoparticles made of the squalene derivative of gemcitabine (SQGem) interact with lipoproteins (LPs), indirectly enabling the targeting of cancer cells with high LP receptors expression. In vitro and in vivo experiments reveal preeminent affinity of the squalene-gemcitabine bioconjugates towards LP particles with the highest cholesterol content and in silico simulations further display their incorporation into the hydrophobic core of LPs. To the best of our knowledge, the use of squalene to induce drug insertion into LPs for indirect cancer cell targeting is a novel concept in drug delivery. Interestingly, not only SQGem but also other squalene derivatives interact similarly with lipoproteins while such interaction is not observed with liposomes. The conjugation to squalene represents a versatile platform that would enable efficient drug delivery by simply exploiting endogenous lipoproteins.

  9. Helix Nebula and CERN: A Symbiotic approach to exploiting commercial clouds

    CERN Multimedia

    Barreiro Megino, Fernando Harald; Kucharczyk, Katarzyna; Medrano Llamas, Ramón; van der Ster, Daniel


    The recent paradigm shift toward cloud computing in IT, and general interest in "Big Data" in particular, have demonstrated that the computing requirements of HEP are no longer globally unique. Indeed, the CERN IT department and LHC experiments have already made significant R&D; investments in delivering and exploiting cloud computing resources. While a number of technical evaluations of interesting commercial offerings from global IT enterprises have been performed by various physics labs, further technical, security, sociological, and legal issues need to be address before their large-scale adoption by the research community can be envisaged. Helix Nebula - the Science Cloud is an initiative that explores these questions by joining the forces of three European research institutes (CERN, ESA and EMBL) with leading European commercial IT enterprises. The goals of Helix Nebula are to establish a cloud platform federating multiple commercial cloud providers, along with new business models, which can sustain...

  10. Modeling a hierarchical structure of factors influencing exploitation policy for water distribution systems using ISM approach (United States)

    Jasiulewicz-Kaczmarek, Małgorzata; Wyczółkowski, Ryszard; Gładysiak, Violetta


    Water distribution systems are one of the basic elements of contemporary technical infrastructure of urban and rural areas. It is a complex engineering system composed of transmission networks and auxiliary equipment (e.g. controllers, checkouts etc.), scattered territorially over a large area. From the water distribution system operation point of view, its basic features are: functional variability, resulting from the need to adjust the system to temporary fluctuations in demand for water and territorial dispersion. The main research questions are: What external factors should be taken into account when developing an effective water distribution policy? Does the size and nature of the water distribution system significantly affect the exploitation policy implemented? These questions have shaped the objectives of research and the method of research implementation.

  11. Conjugation of squalene to gemcitabine as unique approach exploiting endogenous lipoproteins for drug delivery. (United States)

    Sobot, Dunja; Mura, Simona; Yesylevskyy, Semen O; Dalbin, Laura; Cayre, Fanny; Bort, Guillaume; Mougin, Julie; Desmaële, Didier; Lepetre-Mouelhi, Sinda; Pieters, Grégory; Andreiuk, Bohdan; Klymchenko, Andrey S; Paul, Jean-Louis; Ramseyer, Christophe; Couvreur, Patrick


    Once introduced in the organism, the interaction of nanoparticles with various biomolecules strongly impacts their fate. Here we show that nanoparticles made of the squalene derivative of gemcitabine (SQGem) interact with lipoproteins (LPs), indirectly enabling the targeting of cancer cells with high LP receptors expression. In vitro and in vivo experiments reveal preeminent affinity of the squalene-gemcitabine bioconjugates towards LP particles with the highest cholesterol content and in silico simulations further display their incorporation into the hydrophobic core of LPs. To the best of our knowledge, the use of squalene to induce drug insertion into LPs for indirect cancer cell targeting is a novel concept in drug delivery. Interestingly, not only SQGem but also other squalene derivatives interact similarly with lipoproteins while such interaction is not observed with liposomes. The conjugation to squalene represents a versatile platform that would enable efficient drug delivery by simply exploiting endogenous lipoproteins.

  12. New approaches for studying and exploiting an old protuberance, the plant trichome. (United States)

    Wagner, G J; Wang, E; Shepherd, R W


    Much recent study of plant trichomes has focused on various aspects of glandular secreting trichomes (GSTs) and differentiation of simple trichomes. This Botanical Briefing will highlight: research on various aspects of, and manipulation of glandular secreting trichomes; molecular aspects of the differentiation and development of simple trichomes of arabidopsis and cotton; how methods for manipulation of model systems used in the above work can be applied to expand our understanding of less studied surface structures of plants. The Briefing will cover: established and suggested roles of simple and glandular secreting trichomes; recent results regarding solute and ion movement in trichomes; methods for isolating trichomes; recent studies of trichome differentiation and development; attempts to modify metabolism in secreting trichomes; efforts to exploit trichomes for commercial and agronomic purposes.

  13. Non-destructive determination of moisture content and micro-fibril angle of wood using a poly-chromatic X-ray beam theoretical and experimental approach; Exploitation d'un rayonnement X poly-energetique pour la determination de la teneur en eau et de l'angle de microfibrilles du bois: approche theorique et experimentale

    Energy Technology Data Exchange (ETDEWEB)

    Baettig, R


    Non-destructive determination of moisture content and micro-fibril angle are important stakes for the sciences of the wood because these two parameters influence strongly the macroscopic behavior of the wood. For example, the shrinkage, the mechanical properties, the thermal and acoustic conductivity are dependent on the moisture content and their anisotropic character is largely governed by the micro-fibril angle. We used the light difference between X-ray mass attenuation coefficient for the water and for the wood in transmission. Regrettably, the results show that this difference between X-ray mass attenuation coefficient is insufficient to allow the precise measurement of the moisture content.In spite of this, the coherent scattering shows sensitive effects. So, by using a poly-energetic beam and a spectrometric system, we were able to discriminate between the crystalline constituent (cellulose) of the amorphous constituent (water) in a sample of wet wood, because for a given angle these phases scatter in different energy. Besides, the device created allowed us to study the crystalline phase of the wood. We were able to confront experimental profiles of diffraction with theoretical profiles of diffraction, obtained by means of a rigorous simulation, in the objective to estimate the average micro-fibril angle and its standard deviation. (author)

  14. Stone Tool Manufacture Strategies and Lithic Raw Material Exploitation in Coastal Patagonia, Argentina: A Multivariate Approach

    Directory of Open Access Journals (Sweden)

    Marcelo Cardillo


    Full Text Available This paper seeks to characterize strategies of artifact manufacture and lithic raw material exploitation along San Matías Gulf coast, Argentina, using multifactorial and cluster analysis. Multifactorial analysis is a relatively new method that has yet to be used for archaeological analysis; it has the advantage that it allows us to describe data using different groups of qualitative or quantitative variables at the same time. Additionally, cluster analysis was conducted on multifactorial axis in a bid to identify grouping patterns. The results obtained from the combination of these two methods suggest that they may be useful in characterizing technological strategies in the study area. Furthermore, they may also be a powerful exploratory and characterization tool able to generate explanations at low spatial scales. The application of these methods on San Matías Gulf study case suggests that along the western and northern coasts of this Gulf the most important variables in determining differences in resource use were the fragmentation ratio and lithic raw materials used in artifact manufacture.

  15. Experimental Approaches to Understanding Ancient Ecosystems Flammability (United States)

    Belcher, C. M.


    Fire is a natural process integral to the order and function of our planet. It produces unique products that interact with its carbon and nutrient balance. Fires are a significant source of atmospheric carbon dioxide and assist in the regulation of the oxygen content of our atmosphere. Natural fires have occurred on our planet for ~420 million years, where even the first tiny land plants were capable of being ignited and carrying a fire. Evidence for such fires comes from the record of fossil charcoal found, often abundantly, in ancient sediments. Fossil charcoal provides an exceptional means to record not only probable variations in ancient fire activity but also information about ancient plants, not least owing to its three-dimensional preservation of plant anatomy. However, fossil charcoal like all fossils is subject to taphonomic biases which mean that it is hard to decipher exactly what an abundance of charcoal means in the context of fire histories, ancient fire dynamics and ecosystems flammability. Fires require 3 basic ingredients; these are an ignition source, fuel to burn and a source of oxygen. We can therefore consider how variations in the past concentration of atmospheric oxygen and how the evolution of different plant groups and the types of fuel that they provide have influenced fire activity throughout geological time. By going back to basics we can design experiments that assess the fundamental behaviour of fire and the flammability of different fuels. Here I will present some experimental approaches that cross-cut a variety of disciplines within the fire sciences which aim to enhance our understanding of the interplay between fuel variations and past atmospheric composition on broad trends in ancient fire activity.

  16. Helix Nebula and CERN: A Symbiotic approach to exploiting commercial clouds (United States)

    Barreiro Megino, Fernando H.; Jones, Robert; Kucharczyk, Katarzyna; Medrano Llamas, Ramón; van der Ster, Daniel


    The recent paradigm shift toward cloud computing in IT, and general interest in "Big Data" in particular, have demonstrated that the computing requirements of HEP are no longer globally unique. Indeed, the CERN IT department and LHC experiments have already made significant R&D investments in delivering and exploiting cloud computing resources. While a number of technical evaluations of interesting commercial offerings from global IT enterprises have been performed by various physics labs, further technical, security, sociological, and legal issues need to be address before their large-scale adoption by the research community can be envisaged. Helix Nebula - the Science Cloud is an initiative that explores these questions by joining the forces of three European research institutes (CERN, ESA and EMBL) with leading European commercial IT enterprises. The goals of Helix Nebula are to establish a cloud platform federating multiple commercial cloud providers, along with new business models, which can sustain the cloud marketplace for years to come. This contribution will summarize the participation of CERN in Helix Nebula. We will explain CERN's flagship use-case and the model used to integrate several cloud providers with an LHC experiment's workload management system. During the first proof of concept, this project contributed over 40.000 CPU-days of Monte Carlo production throughput to the ATLAS experiment with marginal manpower required. CERN's experience, together with that of ESA and EMBL, is providing a great insight into the cloud computing industry and highlighted several challenges that are being tackled in order to ease the export of the scientific workloads to the cloud environments.


    Directory of Open Access Journals (Sweden)

    Valeriia VOROPAI


    Full Text Available The article is devoted to the front burner problem of effective exploitation of industrial tank-wagons with the presence of residual operation time. The procedure of valuation of tank-cars’ residual operation time for liquid gas transportation was proposed first. Key technical and exploitation parameters of the tank-wagon model 15-1408-10 according to testing loads that simulate loads in real exploitation were approved. The calculation, which, as against existent ones for valuation of universal freight cars’ residual operation time, allows to calculate equivalent stress using test results that rely on a change of internal pressure activity during drainage and filling operations, and the most unfavorable combination of simulation of active loads on a tank-wagon was proposed. The proposed procedure can be adapted for use during valuation of freight cars’ residual operation time, or for other means of transport and machineries.

  18. Grit Trumps Talent? An experimental approach

    DEFF Research Database (Denmark)

    Gerhards, Leonie; Gravert, Christina Annette

    their decision not to shirk, we measure their grittiness experimentally. We find that the original questionnaire measure of grit developed by Duckworth et al. (2007) is significantly correlated with our new experimental measure - even when controlling for ability and a questionnaire measure of self-control...

  19. New Approaches To Off-Shore Wind Energy Management Exploiting Satellite EO Data (United States)

    Morelli, Marco; Masini, Andrea; Venafra, Sara; Potenza, Marco Alberto Carlo


    Wind as an energy resource has been increasingly in focus over the past decades, starting with the global oil crisis in the 1970s. The possibility of expanding wind power production to off-shore locations is attractive, especially in sites where wind levels tend to be higher and more constant. Off-shore high-potential sites for wind energy plants are currently being looked up by means of wind atlases, which are essentially based on NWP (Numerical Weather Prediction) archive data and that supply information with low spatial resolution and very low accuracy. Moreover, real-time monitoring of active off- shore wind plants is being carried out using in-situ installed anemometers, that are not very reliable (especially on long time periods) and that should be periodically substituted when malfunctions or damages occur. These activities could be greatly supported exploiting archived and near real-time satellite imagery, that could provide accurate, global coverage and high spatial resolution information about both averaged and near real-time off-shore windiness. In this work we present new methodologies aimed to support both planning and near-real-time monitoring of off-shore wind energy plants using satellite SAR(Synthetic Aperture Radar) imagery. Such methodologies are currently being developed in the scope of SATENERG, a research project funded by ASI (Italian Space Agency). SAR wind data are derived from radar backscattering using empirical geophysical model functions, thus achieving greater accuracy and greater resolution with respect to other wind measurement methods. In detail, we calculate wind speed from X-band and C- band satellite SAR data, such as Cosmo-SkyMed (XMOD2) and ERS and ENVISAT (CMOD4) respectively. Then, using also detailed models of each part of the wind plant, we are able to calculate the AC power yield expected behavior, which can be used to support either the design of potential plants (using historical series of satellite images) or the

  20. Novel approach to the exploitation of the tidal energy. Volume 1: Summary and discussion (United States)

    Gorlov, A. M.


    The hydropneumatic concept in the approach to harnessing low tidal hydropower is discussed. The energy of water flow is converted into the energy of an air jet by a specialized air chamber which is placed on the ocean floor across a flowing watercourse. Water passes through the chamber where it works as a natural piston compressing air in the upper part of the closure. Compressed air is used as a new working plenum to drive air turbines. The kinetic energy of an air jet provided by the air chamber is sufficient for stable operation of industrial air turbines. It is possible to use light plastic barriers instead of conventional rigid dams (the water sail concept). It is confirmed that the concept can result in a less expensive and more effective tidal power plant project than the conventional hydroturbine approach.

  1. Recent developments in automatic solid-phase extraction with renewable surfaces exploiting flow-based approaches

    DEFF Research Database (Denmark)

    Miró, Manuel; Hartwell, Supaporn Kradtap; Jakmunee, Jaroon


    Solid-phase extraction (SPE) is the most versatile sample-processing method for removal of interfering species and/or analyte enrichment. Although significant advances have been made over the past two decades in automating the entire analytical protocol involving SPE via flow-injection approaches...... chemical-derivatization reactions, and it pinpoints the most common instrumental detection techniques utilized. We present and discuss in detail relevant environmental and bioanalytical applications reported in the past few years....

  2. Waves and Wine: Advanced approaches for characterizing and exploiting micro-terroir (United States)

    Hubbard, S. S.; Grote, K. R.; Freese, P.; Peterson, J. E.; Rubin, Y.


    Development of viticultural strategies that are focused on promoting uniformly high quality wine grapes requires an understanding of the properties that influence wine grape development. Our objective is to explore the spatial and temporal variability of above and below ground factors that can influence grape variability at the block scale (or micro-terroir) using a combination of conventional point measurements and non-invasive geophysical approaches, and to use that information to guide the development of new vineyards or the management of existing vineyards. Climate clearly plays a dominant role in determining the success of certain viticultural regions or vintages. However, wine grapes of the same variety, which are grown in the same microclimate region and cultivated and made into wine using identical practices, can lead to remarkably different wines when the grapes are grown on different types of soils. The soil texture controls soil water availability, which greatly influences grapevine physiological status, vegetative and reproductive growth, and ultimately red wine grape quality. One aspect of our research has focused on developing surface geophysical methods, particularly ground penetrating radar (GPR), to characterize soil texture variability and to monitor vineyard water content. Through testing the approaches in three California wineries, we find that analysis of GPR groundwave and reflected waves enable mapping of shallow soil water content in high resolution, with acceptable accuracy, and in a non-invasive manner, and that use of multiple GPR methods and frequencies offer the potential to characterize the soil in 3-D space. We use the dense data to explore spatial and temporal correlations in soil water content, soil texture, and vegetation vigor and the associated implications for vineyard management. We also describe a new zonal-based vineyard development strategy that honors the natural variability of the site, or the micro-terrior. The approach

  3. Managing Cybersecurity Research and Experimental Development: The REVO Approach

    National Research Council Canada - National Science Library

    Dan Craigen; Drew Vandeth; D'Arcy Walsh


      We present a systematic approach for managing a research and experimental development cybersecurity program that must be responsive to continuously evolving cybersecurity, and other, operational concerns...

  4. Current and upcoming approaches to exploit the reversibility of epigenetic mutations in breast cancer. (United States)

    Falahi, Fahimeh; van Kruchten, Michel; Martinet, Nadine; Hospers, Geke A P; Rots, Marianne G


    DNA methylation and histone modifications are important epigenetic modifications associated with gene (dys)regulation. The epigenetic modifications are balanced by epigenetic enzymes, so-called writers and erasers, such as DNA (de)methylases and histone (de)acetylases. Aberrant epigenetic alterations have been associated with various diseases, including breast cancer. Since aberrant epigenetic modifications are potentially reversible, they might represent targets for breast cancer therapy. Indeed, several drugs have been designed to inhibit epigenetic enzymes (epi-drugs), thereby reversing epigenetic modifications. US Food and Drug Administration approval has been obtained for some epi-drugs for hematological malignancies. However, these drugs have had very modest anti-tumor efficacy in phase I and II clinical trials in breast cancer patients as monotherapy. Therefore, current clinical trials focus on the combination of epi-drugs with other therapies to enhance or restore the sensitivity to such therapies. This approach has yielded some promising results in early phase II trials. The disadvantage of epi-drugs, however, is genome-wide effects, which may cause unwanted upregulation of, for example, pro-metastatic genes. Development of gene-targeted epigenetic modifications (epigenetic editing) in breast cancer can provide a novel approach to prevent such unwanted events. In this context, identification of crucial epigenetic modifications regulating key genes in breast cancer is of critical importance. In this review, we first describe aberrant DNA methylation and histone modifications as two important classes of epigenetic mutations in breast cancer. Then we focus on the preclinical and clinical epigenetic-based therapies currently being explored for breast cancer. Finally, we describe epigenetic editing as a promising new approach for possible applications towards more targeted breast cancer treatment.

  5. Exploiting Flexibility in Coupled Electricity and Natural Gas Markets: A Price-Based Approach

    DEFF Research Database (Denmark)

    Ordoudis, Christos; Delikaraoglou, Stefanos; Pinson, Pierre


    Natural gas-fired power plants (NGFPPs) are considered a highly flexible component of the energy system and can facilitate the large-scale integration of intermittent renewable generation. Therefore, it is necessary to improve the coordination between electric power and natural gas systems....... Considering a market-based coupling of these systems, we introduce a decision support tool that increases market efficiency in the current setup where day-ahead and balancing markets are cleared sequentially. The proposed approach relies on the optimal adjustment of natural gas price to modify the scheduling...

  6. Interdisciplinary approach to exploit the tectonic memory in the continental crust of collisional belts. (United States)

    Gosso, G.; Marotta, A. M.; Rebay, G.; Regorda, A.; Roda, M.; Spalla, M. I.; Zanoni, D.; Zucali, M.


    Collisional belts result by thoroughly competing thermo-mechanical disaggregation and coupling within both continental and oceanic lithospheric slices, during construction of tectono-metamorphic architectures. In multiply reworked metamorphics, tectonic units may be contoured nowadays on the base of coherent thermo-baric and structural time-sequences rather than simply relying on lithologic affinities. Sequences of equilibrium assemblages and related fabric imprints are an approach that appears as a more reliable procedure, that enables to define tectonic units as the volume of crustal slices that underwent corresponding variations during the dynamics of an active margin and takes into account a history of physical imprints. The dimensions of these tectonic units may have varied over time and must be reconstructed combining the tracers of structural and metamorphic changes of basement rocks, since such kind of tectono-metamorphic units (TMUs) is a realistic configuration of the discrete portions of orogenic crust that experienced a coherent sequence of metamorphic and textural variations. Their translational trajectories, and bulk shape changes during deformation, cannot simply be derived from the analysis of the geometries and kinematics of tectonic units, but are to be obtained by adding the reconstruction of quantitative P-T-d-t paths making full use of fossil mineral equilibria. The joint TMU field-and-laboratory definition is an investigation procedure that bears a distinct thermo-tectonic connotation, that, through modelling, offers the opportunity to test the physical compatibilities of plate-scale interconnected variables, such as density, viscosity, and heat transfer, with respect to what current interpretative geologic histories may imply. Comparison between predictions from numerical modelling and natural data obtained by this analytical approach can help to solve ambiguities on geodynamic significance of structural and thermal signatures, also as a

  7. A multitemporal probabilistic error correction approach to SVM classification of alpine glacier exploiting sentinel-1 images (Conference Presentation) (United States)

    Callegari, Mattia; Marin, Carlo; Notarnicola, Claudia; Carturan, Luca; Covi, Federico; Galos, Stephan; Seppi, Roberto


    In mountain regions and their forelands, glaciers are key source of melt water during the middle and late ablation season, when most of the winter snow has already melted. Furthermore, alpine glaciers are recognized as sensitive indicators of climatic fluctuations. Monitoring glacier extent changes and glacier surface characteristics (i.e. snow, firn and bare ice coverage) is therefore important for both hydrological applications and climate change studies. Satellite remote sensing data have been widely employed for glacier surface classification. Many approaches exploit optical data, such as from Landsat. Despite the intuitive visual interpretation of optical images and the demonstrated capability to discriminate glacial surface thanks to the combination of different bands, one of the main disadvantages of available high-resolution optical sensors is their dependence on cloud conditions and low revisit time frequency. Therefore, operational monitoring strategies relying only on optical data have serious limitations. Since SAR data are insensitive to clouds, they are potentially a valid alternative to optical data for glacier monitoring. Compared to past SAR missions, the new Sentinel-1 mission provides much higher revisit time frequency (two acquisitions each 12 days) over the entire European Alps, and this number will be doubled once the Sentinel1-b will be in orbit (April 2016). In this work we present a method for glacier surface classification by exploiting dual polarimetric Sentinel-1 data. The method consists of a supervised approach based on Support Vector Machine (SVM). In addition to the VV and VH signals, we tested the contribution of local incidence angle, extracted from a digital elevation model and orbital information, as auxiliary input feature in order to account for the topographic effects. By exploiting impossible temporal transition between different classes (e.g. if at a given date one pixel is classified as rock it cannot be classified as

  8. Computational and Experimental Approaches to Visual Aesthetics. (United States)

    Brachmann, Anselm; Redies, Christoph


    Aesthetics has been the subject of long-standing debates by philosophers and psychologists alike. In psychology, it is generally agreed that aesthetic experience results from an interaction between perception, cognition, and emotion. By experimental means, this triad has been studied in the field of experimental aesthetics , which aims to gain a better understanding of how aesthetic experience relates to fundamental principles of human visual perception and brain processes. Recently, researchers in computer vision have also gained interest in the topic, giving rise to the field of computational aesthetics . With computing hardware and methodology developing at a high pace, the modeling of perceptually relevant aspect of aesthetic stimuli has a huge potential. In this review, we present an overview of recent developments in computational aesthetics and how they relate to experimental studies. In the first part, we cover topics such as the prediction of ratings, style and artist identification as well as computational methods in art history, such as the detection of influences among artists or forgeries. We also describe currently used computational algorithms, such as classifiers and deep neural networks. In the second part, we summarize results from the field of experimental aesthetics and cover several isolated image properties that are believed to have a effect on the aesthetic appeal of visual stimuli. Their relation to each other and to findings from computational aesthetics are discussed. Moreover, we compare the strategies in the two fields of research and suggest that both fields would greatly profit from a joined research effort. We hope to encourage researchers from both disciplines to work more closely together in order to understand visual aesthetics from an integrated point of view.

  9. Exploiting in situ antigen generation and immune modulation to enhance chemotherapy response in advanced melanoma: A combination nanomedicine approach. (United States)

    Lu, Yao; Wang, Yuhua; Miao, Lei; Haynes, Matthew; Xiang, Guangya; Huang, Leaf


    Therapeutic anticancer vaccine development must address a number of barriers to achieve successful tumor specific killing, including effective antigen presentation and antigen-specific T-cell activation to mediate cytotoxic cellular effects, inhibition of an immune-suppressive tumor microenvironment in order to facilitate and enhance CTL activity, and induction of memory T-cells to prolong tumor rejection. While traditional as well as modern vaccines rely upon delivery of both antigen and adjuvant, a variety of clinically relevant cancers lack ideal immunogenic antigens. Building upon recent efforts, we instead chose to exploit chemotherapy-induced apoptosis to allow for in situ antigen generation in a combination, nanomedicine-based approach. Specifically, lipid-coated cisplatin nanoparticles (LPC) and CpG-encapsulated liposomes (CpG-Lipo) were prepared for the temporally-controlled and multifaceted treatment of an advanced in vivo model of melanoma. Such combination therapy established strong synergistic effects, both in apoptotic extent and subsequent abrogation of tumor growth, which were due largely to both an enhanced cytotoxic T-cell recruitment and a reduction of immune-suppressive mediators in the microenvironments of both spleens and tumor. These results underlie a prolonged host lifespan in the combination approach (45 days) as compared with control (25 days, p nanomedicine by establishing effect synergy in host-specific immunotherapy following chemotherapy. Copyright © 2016. Published by Elsevier Ireland Ltd.

  10. Exploiting neurovascular coupling: a Bayesian sequential Monte Carlo approach applied to simulated EEG fNIRS data (United States)

    Croce, Pierpaolo; Zappasodi, Filippo; Merla, Arcangelo; Chiarelli, Antonio Maria


    Objective. Electrical and hemodynamic brain activity are linked through the neurovascular coupling process and they can be simultaneously measured through integration of electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS). Thanks to the lack of electro-optical interference, the two procedures can be easily combined and, whereas EEG provides electrophysiological information, fNIRS can provide measurements of two hemodynamic variables, such as oxygenated and deoxygenated hemoglobin. A Bayesian sequential Monte Carlo approach (particle filter, PF) was applied to simulated recordings of electrical and neurovascular mediated hemodynamic activity, and the advantages of a unified framework were shown. Approach. Multiple neural activities and hemodynamic responses were simulated in the primary motor cortex of a subject brain. EEG and fNIRS recordings were obtained by means of forward models of volume conduction and light propagation through the head. A state space model of combined EEG and fNIRS data was built and its dynamic evolution was estimated through a Bayesian sequential Monte Carlo approach (PF). Main results. We showed the feasibility of the procedure and the improvements in both electrical and hemodynamic brain activity reconstruction when using the PF on combined EEG and fNIRS measurements. Significance. The investigated procedure allows one to combine the information provided by the two methodologies, and, by taking advantage of a physical model of the coupling between electrical and hemodynamic response, to obtain a better estimate of brain activity evolution. Despite the high computational demand, application of such an approach to in vivo recordings could fully exploit the advantages of this combined brain imaging technology.

  11. Flaw shape reconstruction – an experimental approach

    Directory of Open Access Journals (Sweden)

    Marilena STANCULESCU


    Full Text Available Flaws can be classified as acceptable and unacceptable flaws. As a result of nondestructive testing, one takes de decision Admit/Reject regarding the tested product related to some acceptability criteria. In order to take the right decision, one should know the shape and the dimension of the flaw. On the other hand, the flaws considered to be acceptable, develop in time, such that they can become unacceptable. In this case, the knowledge of the shape and dimension of the flaw allows determining the product time life. For interior flaw shape reconstruction the best procedure is the use of difference static magnetic field. We have a stationary magnetic field problem, but we face the problem given by the nonlinear media. This paper presents the results of the experimental work for control specimen with and without flaw.

  12. An ethnomethodological approach to examine exploitation in the context of capacity, trust and experience of commercial surrogacy in India

    National Research Council Canada - National Science Library

    Saravanan, Sheela


    The socio-ethical concerns regarding exploitation in commercial surrogacy are premised on asymmetric vulnerability and the commercialization of women's reproductive capacity to suit individualistic motives...

  13. Understanding bimolecular machines: Theoretical and experimental approaches (United States)

    Goler, Adam Scott

    This dissertation concerns the study of two classes of molecular machines from a physical perspective: enzymes and membrane proteins. Though the functions of these classes of proteins are different, they each represent important test-beds from which new understanding can be developed by the application of different techniques. HIV1 Reverse Transcriptase is an enzyme that performs multiple functions, including reverse transcription of RNA into an RNA/DNA duplex, RNA degradation by the RNaseH domain, and synthesis of dsDNA. These functions allow for the incorporation of the retroviral genes into the host genome. Its catalytic cycle requires repeated large-scale conformational changes fundamental to its mechanism. Motivated by experimental work, these motions were studied theoretically by the application of normal mode analysis. It was observed that the lowest order modes correlate with largest amplitude (low-frequency) motion, which are most likely to be catalytically relevant. Comparisons between normal modes obtained via an elastic network model to those calculated from the essential dynamics of a series of all-atom molecular dynamics simulations show the self-consistency between these calculations. That similar conformational motions are seen between independent theoretical methods reinforces the importance of large-scale subdomain motion for the biochemical action of DNA polymerases in general. Moreover, it was observed that the major subunits of HIV1 Reverse Transcriptase interact quasi-harmonically. The 5HT3A Serotonin receptor and P2X1 receptor, by contrast, are trans-membrane proteins that function as ligand gated ion channels. Such proteins feature a central pore, which allows for the transit of ions necessary for cellular function across a membrane. The pore is opened by the ligation of binding sites on the extracellular portion of different protein subunits. In an attempt to resolve the individual subunits of these membrane proteins beyond the diffraction

  14. Redefining Exploitation

    DEFF Research Database (Denmark)

    Agarwala, Rina


    -employed workers are organizing as workers. They are fighting labor exploitation by redefining the concept to include additional exploitation axes (from the state and middle class) and forms (including sexual). In doing so, they are redefining potential solutions, including identities and material benefits, to fit...... their unique needs. By expanding the category of “workers” beyond those defined by a narrow focus on a standard employer-employee relationship, these movements are also fighting exclusion from earlier labor protections by increasing the number of entitled beneficiaries. These struggles provide an important...

  15. An ethnomethodological approach to examine exploitation in the context of capacity, trust and experience of commercial surrogacy in India. (United States)

    Saravanan, Sheela


    The socio-ethical concerns regarding exploitation in commercial surrogacy are premised on asymmetric vulnerability and the commercialization of women's reproductive capacity to suit individualistic motives. In examining the exploitation argument, this article reviews the social contract theory that describes an individual as an 'economic man' with moral and/or political motivations to satisfy individual desires. This study considers the critique by feminists, who argue that patriarchal and medical control prevails in the surrogacy contracts. It also explores the exploitative dynamics amongst actors in the light of Baier's conceptualization of trust and human relationship, within which both justice and exploitation thrive, and Foucault's concept of bio-power. Drawing on these concepts, this paper aims to investigate the manifestations of exploitation in commercial surrogacy in the context of trust, power and experiences of actors, using a case study of one clinic in India. The actors' experiences are evaluated at different stages of the surrogacy process: recruitment, medical procedures, living in the surrogate home, bonding with the child and amongst actors, financial dealings, relinquishment and post-relinquishment.This study applies ethnomethodology to identify phenomena as perceived by the actors in a situation, giving importance to their interpretations of the rules that make collective activity possible. The methods include semi-structured interviews, discussions, participant observation and explanation of the phenomena from the actors' perspectives. Between August 2009 and April 2010, 13 surrogate mothers (SMs), 4 intended parents (IPs) and 2 medical practitioners (MPs) from one clinic in Western India were interviewed.This study reveals that asymmetries of capacity amongst the MPs, SMs, IPs and surrogate agents (SAs) lead to a network of trust and designation of powers through rules, bringing out the relevance of Baier's conceptualization of asymmetric

  16. Is Kissamos Bay in NW Crete, Greece worth to be exploited as a marine aggregates deposit? An integrated approach (United States)

    Anastasatou, Marianthi; Tsoutsia, Antonia; Petrakis, Stelios; Rousakis, Grigoris; Karditsa, Aikaterini; Hasiotis, Thomas; Kapsimalis, Vasilios; Poulos, Serafim; Stamatakis, Michael


    This study uses an integrated approach to investigate the offshore area of Kissamos Bay, NW Crete Island, Greece, as a prospective marine aggregate (MA) deposit. Non-fuel marine minerals and especially marine aggregates (sand and gravel) are reviewed from the perspective of resources during the last decades. The possible MA deposit of Kissamos Bay was explored during the implementation of the research project THALES-MARE, considering existing information of previous extraction activities in the wider area. Kissamos Bay is located at the inner continental shelf off NW Crete. The onshore basement rocks are composed of Mesozoic to Eocene limestones, shale and sandstone units, along with Neogene sediments such as marls, sandstones and claystones, which locally host Messinian gypsum layers. Sixteen sea-bottom sediment samples were collected with a Smith-McIntyretype grab along four transects, vertical to the shoreline, at water depths of 11 to 44m. A sub-bottom acoustic profiler survey was conducted in order to quantitatively determine the deposit (dimensions and structure). Mineralogical, geochemical, sedimentological and benthic analyses of the samples were carried out, in order to determine the quality of the reservoir and the environmental impact of a potential exploitation. Mineralogical results indicated that the bulk samples consist predominantly of quartz, while calcite occurs as a second significant phase. Chemical analysis of major and trace elements revealed that the average SiO2 content is around 55% with samples closer to the beach (depths applications. Acknowledgments: This work was supported by the research program THALES-MARE (MIS: 375655), funded by the Operational Programme "Education and lifelong learning, 2007-2013" of the Ministry of Education and Religious Affairs, Culture and Sports.

  17. Statistical approach for uncertainty quantification of experimental modal model parameters

    DEFF Research Database (Denmark)

    Luczak, M.; Peeters, B.; Kahsin, M.


    . This paper aims at a systematic approach for uncertainty quantification of the parameters of the modal models estimated from experimentally obtained data. Statistical analysis of modal parameters is implemented to derive an assessment of the entire modal model uncertainty measure. Investigated structures...... estimates obtained from vibration experiments. Modal testing results are influenced by numerous factors introducing uncertainty to the measurement results. Different experimental techniques applied to the same test item or testing numerous nominally identical specimens yields different test results...

  18. An experimental study addressing the use of geoforensic analysis for the exploitation of improvised explosive devices (IEDs). (United States)

    Wilks, Beth; Morgan, Ruth M; Rose, Neil L


    The use of geoforensic analysis in criminal investigations is continuing to develop, with the diversification of analytical techniques, many of which are semi-automated, facilitating prompt analysis of large sample sets at a relatively low cost. Whilst micro-scale geoforensic analysis has been shown to assist criminal investigations including homicide (Concheri et al., 2011 [1]), wildlife crime (Morgan et al., 2006 [2]), illicit drug distribution (Stanley, 1992 [3]), and burglary (Mildenhall, 2006 [4]), its application to the pressing international security threat posed by Improvised Explosive Devices (IEDs) is yet to be considered. This experimental study simulated an IED supply chain from the sourcing of raw materials through to device emplacement. Mineralogy, quartz grain surface texture analysis (QGSTA) and particle size analysis (PSA) were used to assess whether environmental materials were transferred and subsequently persisted on the different components of three pressure plate IEDs. The research also addressed whether these samples were comprised of material from single or multiple geographical provenances that represented supply chain activity nodes. The simulation demonstrated that material derived from multiple activity nodes, was transferred and persisted on device components. The results from the mineralogy and QGSTA illustrated the value these techniques offer for the analysis of mixed provenance samples. The results from the PSA, which produces a bulk signature of the sample, failed to distinguish multiple provenances. The study also considered how the environmental material recovered could be used to generate information regarding the geographical locations the device had been in contact with, in an intelligence style investigation, and demonstrated that geoforensic analysis has the potential to be of value to international counter-IED efforts. It is a tool that may be used to prevent the distribution of large quantities of devices, by aiding the

  19. When death approaches: reverting or exploiting emergent inequity in a complex land-use table-board game

    Directory of Open Access Journals (Sweden)

    Luís García-Barrios


    Full Text Available The lives of poor landowners in tropical mountains depend upon their collective capacity to create and coordinate social preferences derived from their interacting communalistic, hierarchical, and reciprocal exchanges. External actors currently contend for these territories under market rules that are modifying such preferences. We present the design, experimental implementation, and analysis of results of a four-player, land-use board game with stark resource and livelihood limits and coordination/cooperation challenges, as played (separately by 116 farmers and 108 academics, mainly in the tropical mountains of Chiapas, Mexico. In game session one, we trained and framed players in moral economy, a human core feeling and communalistic norm of solidarity and mutual obligation, which translates into "all players must survive." In session two, we explored to what extent moral economy resisted as a social preference under a hypothetical external monetary incentive scheme unfavorable to it. Using an approach that combines spot game analysis and experimental work, we studied the social preferences that emerged during session two among advantaged and disadvantaged players to deal with inequity in land appropriation and use when imminent "death" approaches. We make comparisons between farmers and academics. Players evolved moral economy, competitive domination, i.e., let competition decide, and coalition, i.e., advantaged players ask the dying to surrender land and die prematurely in exchange for a share of the dismal profits. Farmers basically stuck to the first two preferences in similar proportions whereas academics clearly shifted to coalition, a last-resort choice, which allowed disadvantaged players some final leverage and advantaged players use of liberated resources to improve efficiency. Coalition as strategic cooperation among the unequal is part of the culture in which academics are being educated as sustainability professionals and toward

  20. What Shapes the Intention to Study Abroad? An Experimental Approach (United States)

    Petzold, Knut; Moog, Petra


    In contrast to previous studies, this investigation aims to get deeper insights into the causes of the intention to study abroad by using an experimental approach. Although international experience is often considered as important, many students at German universities do not even consider abroad. Referring to the Theory of Rational Choice (RCT)…

  1. The Poisson Distribution: An Experimental Approach to Teaching Statistics (United States)

    Lafleur, Mimi S.; And Others


    Explains an experimental approach to teaching statistics to students who are essentially either non-science and non-mathematics majors or just beginning study of science. With every day examples, the article illustrates the method of teaching Poisson Distribution. (PS)

  2. Combining Theoretical and Experimental Approaches to Understand the Circadian Clock

    NARCIS (Netherlands)

    Merrow, Martha; Dragovic, Zdravko; Tan, Ying; Meyer, Gundela; Sveric, Kruno; Mason, Moyra; Ricken, Jan; Roenneberg, Till


    This review is intended as a summary of our work carried out as part of the German Research Association (DFG) Center Program on Circadian Rhythms. Over the last six years, our approach to understanding circadian systems combined theoretical and experimental tools, and Gonyaulax and Neurospora have

  3. Pruning Chinese trees : an experimental and modelling approach

    NARCIS (Netherlands)

    Zeng, Bo


    Pruning of trees, in which some branches are removed from the lower crown of a tree, has been extensively used in China in silvicultural management for many purposes. With an experimental and modelling approach, the effects of pruning on tree growth and on the harvest of plant material were studied.

  4. Learning Metasploit exploitation and development

    CERN Document Server

    Balapure, Aditya


    A practical, hands-on tutorial with step-by-step instructions. The book will follow a smooth and easy-to-follow tutorial approach, covering the essentials and then showing the readers how to write more sophisticated exploits.This book targets exploit developers, vulnerability analysts and researchers, network administrators, and ethical hackers looking to gain advanced knowledge in exploitation development and identifying vulnerabilities. The primary goal is to take readers wishing to get into more advanced exploitation discovery and reaching the next level.Prior experience exploiting basic st

  5. Parametric and experimental analysis using a power flow approach (United States)

    Cuschieri, J. M.


    A structural power flow approach for the analysis of structure-borne transmission of vibrations is used to analyze the influence of structural parameters on transmitted power. The parametric analysis is also performed using the Statistical Energy Analysis approach and the results are compared with those obtained using the power flow approach. The advantages of structural power flow analysis are demonstrated by comparing the type of results that are obtained by the two analytical methods. Also, to demonstrate that the power flow results represent a direct physical parameter that can be measured on a typical structure, an experimental study of structural power flow is presented. This experimental study presents results for an L shaped beam for which an available solution was already obtained. Various methods to measure vibrational power flow are compared to study their advantages and disadvantages.

  6. Managing Cybersecurity Research and Experimental Development: The REVO Approach

    Directory of Open Access Journals (Sweden)

    Dan Craigen


    Full Text Available We present a systematic approach for managing a research and experimental development cybersecurity program that must be responsive to continuously evolving cybersecurity, and other, operational concerns. The approach will be of interest to research-program managers, academe, corporate leads, government leads, chief information officers, chief technology officers, and social and technology policy analysts. The approach is compatible with international standards and procedures published by the Organisation for Economic Co-operation and Development (OECD and the Treasury Board of Canada Secretariat (TBS. The key benefits of the approach are the following: i the breadth of the overall (cybersecurity space is described; ii depth statements about specific (cybersecurity challenges are articulated and mapped to the breadth of the problem; iii specific (cybersecurity initiatives that have been resourced through funding or personnel are tracked and linked to specific challenges; and iv progress is assessed through key performance indicators. Although we present examples from cybersecurity, the method may be transferred to other domains. We have found the approach to be rigorous yet adaptive to change; it challenges an organization to be explicit about the nature of its research and experimental development in a manner that fosters alignment with evolving business priorities, knowledge transfer, and partner engagement.

  7. A Bayesian experimental design approach to structural health monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, Charles [Los Alamos National Laboratory; Flynn, Eric [UCSD; Todd, Michael [UCSD


    Optimal system design for SHM involves two primarily challenges. The first is the derivation of a proper performance function for a given system design. The second is the development of an efficient optimization algorithm for choosing a design that maximizes, or nearly maximizes the performance function. In this paper we will outline how an SHM practitioner can construct the proper performance function by casting the entire design problem into a framework of Bayesian experimental design. The approach demonstrates how the design problem necessarily ties together all steps of the SHM process.

  8. Contact drying: a review of experimental and mechanistic modeling approaches. (United States)

    Sahni, Ekneet Kaur; Chaudhuri, Bodhisattwa


    Drying is one of the most complex unit operations with simultaneous heat and mass transfer. The contact drying process is also not well understood as several physical phenomena occur concurrently. This paper reviews current experimental and modeling approaches employed towards a better understanding of the contact drying operation. Additionally, an overview of some fundamental aspects relating to contact drying is provided. A brief discussion of some model extensions such as incorporation of noncontact forces, interstitial fluids and attrition rate is also presented. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Experimental measurements of motion cue effects on STOL approach tasks (United States)

    Ringland, R. F.; Stapleford, R. L.


    An experimental program to investigate the effects of motion cues on STOL approach is presented. The simulator used was the Six-Degrees-of-Freedom Motion Simulator (S.01) at Ames Research Center of NASA which has ?2.7 m travel longitudinally and laterally and ?2.5 m travel vertically. Three major experiments, characterized as tracking tasks, were conducted under fixed and moving base conditions: (1) A simulated IFR approach of the Augmentor Wing Jet STOL Research Aircraft (AWJSRA), (2) a simulated VFR task with the same aircraft, and (3) a single-axis task having only linear acceleration as the motion cue. Tracking performance was measured in terms of the variances of several motion variables, pilot vehicle describing functions, and pilot commentary.

  10. Developing a new cost-efficient control strategy for an actual confectionery plant through the combined exploitation of experimental and numerical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lunghi, Piero; Mariani, Francesco [Universita di Perugia, Dip. di Ingegneria Industriale, Perugia (Italy)


    Achieving energy absorption reductions while improving indoor air quality is a major task when designing new air conditioning systems. A cost-effective way to improve energy efficiency without compromising the thermal comfort consists of developing better control. In the present work, an extensive experimental campaign has been coupled with a theoretical analysis with an effective approach. A simulation tool has been implemented and, through its predictions, an efficient control strategy has been developed in a system that resulted in significant energy savings and environmental benefits. (Author)

  11. Vanadium supersaturated silicon system: a theoretical and experimental approach (United States)

    Garcia-Hemme, Eric; García, Gregorio; Palacios, Pablo; Montero, Daniel; García-Hernansanz, Rodrigo; Gonzalez-Diaz, Germán; Wahnon, Perla


    The effect of high dose vanadium ion implantation and pulsed laser annealing on the crystal structure and sub-bandgap optical absorption features of V-supersaturated silicon samples has been studied through the combination of experimental and theoretical approaches. Interest in V-supersaturated Si focusses on its potential as a material having a new band within the Si bandgap. Rutherford backscattering spectrometry measurements and formation energies computed through quantum calculations provide evidence that V atoms are mainly located at interstitial positions. The response of sub-bandgap spectral photoconductance is extended far into the infrared region of the spectrum. Theoretical simulations (based on density functional theory and many-body perturbation in GW approximation) bring to light that, in addition to V atoms at interstitial positions, Si defects should also be taken into account in explaining the experimental profile of the spectral photoconductance. The combination of experimental and theoretical methods provides evidence that the improved spectral photoconductance up to 6.2 µm (0.2 eV) is due to new sub-bandgap transitions, for which the new band due to V atoms within the Si bandgap plays an essential role. This enables the use of V-supersaturated silicon in the third generation of photovoltaic devices.

  12. Analyzing patterns in experts' approaches to solving experimental problems (United States)

    Čančula, Maja Poklinek; Planinšič, Gorazd; Etkina, Eugenia


    We report detailed observations of three pairs of expert scientists and a pair of advanced undergraduate students solving an experimental optics problem. Using a new method ("transition graphs") of visualizing sequences of logical steps, we were able to compare the groups and identify patterns that could not be found using previously existing methods. While the problem solving of undergraduates significantly differed from that of experts at the beginning of the process, it gradually became more similar to the expert problem solving. We mapped problem solving steps and their sequence to the elements of an approach to teaching and learning physics called Investigative Science Learning Environment (ISLE), and we speculate that the ISLE educational framework closely represents the actual work of physicists.

  13. Review on dry reforming of methane, a potentially more environmentally-friendly approach to the increasing natural gas exploitation. (United States)

    Lavoie, Jean-Michel


    With the actual growth of the natural gas industry in the US as well as the potential and availability of this non-renewable carbon source worldwide, reforming of methane gas is getting increasing attention. Methane can be used for the production of heat or electricity, as well, it can be converted to syngas, a building block that could lead to the production of liquid fuels and chemicals, a very promising pathway in light of the increasing price of oil. Amongst the different reforming techniques, dry reforming could represent a very interesting approach both to valorize a cheap source or carbon (CO2) as well as to reduce the overall carbon footprint of the increasing worldwide fossil-based methane consumption. In this short review, attention will be given to the thermodynamics of dry reforming followed by an investigation on dry reforming using heterogeneous catalyst by focusing on the most popular elements used in literature for dry reforming. Attention will as well be given to other emerging techniques that may allow countering at one point the high thermodynamic penalties that accompanies conversion of methane using carbon dioxide.

  14. Identification of putative vaccine candidates against Helicobacter pylori exploiting exoproteome and secretome: a reverse vaccinology based approach. (United States)

    Naz, Anam; Awan, Faryal Mehwish; Obaid, Ayesha; Muhammad, Syed Aun; Paracha, Rehan Zafar; Ahmad, Jamil; Ali, Amjad


    Helicobacter pylori (H. pylori) is an important pathogen associated with diverse gastric disorders ranging from peptic ulcer to malignancy. It has also been recognized by the World Health Organization (WHO) as class I carcinogen. Conventional treatment regimens for H. pylori seem to be ineffective, possibly due to antibiotic resistance mechanisms acquired by the pathogen. In this study we have successfully employed a reverse vaccinology approach to predict the potential vaccine candidates against H. pylori. The predicted potential vaccine candidates include vacA, babA, sabA, fecA and omp16. Host-pathogen interactions analysis elaborated their direct or indirect role in the specific signaling pathways including epithelial cell polarity, metabolism, secretion system and transport. Furthermore, surface-exposed antigenic epitopes were predicted and analyzed for conservation among 39 complete genomes of H. pylori (Genbank) for all the candidate proteins. These epitopes may serve as a base for the development of broad spectrum peptide or multi-component vaccines against H. pylori. We also believe that the proposed pipeline can be extended to other pathogens and for the identification of novel candidates for the development of effective vaccines. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Review on dry reforming of methane, a potentially more environmentally-friendly approach to the increasing natural gas exploitation (United States)

    Lavoie, Jean-Michel


    With the actual growth of the natural gas industry in the US as well as the potential and availability of this non-renewable carbon source worldwide, reforming of methane gas is getting increasing attention. Methane can be used for the production of heat or electricity, as well, it can be converted to syngas, a building block that could lead to the production of liquid fuels and chemicals, a very promising pathway in light of the increasing price of oil. Amongst the different reforming techniques, dry reforming could represent a very interesting approach both to valorize a cheap source or carbon (CO2) as well as to reduce the overall carbon footprint of the increasing worldwide fossil-based methane consumption. In this short review, attention will be given to the thermodynamics of dry reforming followed by an investigation on dry reforming using heterogeneous catalyst by focusing on the most popular elements used in literature for dry reforming. Attention will as well be given to other emerging techniques that may allow countering at one point the high thermodynamic penalties that accompanies conversion of methane using carbon dioxide. PMID:25426488

  16. Thermoelectric conversion of heat fluxes: analytical and experimental approach (United States)

    Amokrane, Mounir; Nogarede, Bertrand


    When considering electric energy harvesting from waste heat, two different solutions of direct conversion are possible: pyroelectric and thermoelectric conversions. This paper presents a study of the thermoelectric conversion by two different approaches: analytical and experimental. Furthermore, a brief historical description of the discovery and early years of development of thermoelectricity is presented. The essential objective of this work is to develop a numerical tool that can estimate the output quantities of a thermoelectric converter, without knowing all its features. For this, two analytical models were developed, based on electrical and thermal phenomena occurring within the active element. The results obtained by this model were compared successfully with experiments carried out on an industrial thermoelectric element. Considering the centimetric size of the device (16 cm2 area), the electrical power recovered by this conversion varies from 16 to 80 mW for a temperature difference between 2 and 18 °C and according to the load value. In addition, both models transcribe the behavior of the active element with an accuracy of about 10%. In agreement with this, the output voltages reached are of the same magnitude for the models and the experimental values and vary from 0.1 to 0.8 V depending on the load connected and the type of convection. Another issue which is discussed for the two cases is that an optimal recovered energy is obtained for a given electric load taking into account the physical characteristics of the considered thermoelectric element. Finally, a conversion efficiency calculation has shown that it is possible to reach 45% of the Carnot efficiency. This denotes the interest to perform load matching to optimize the output power.

  17. Influence of Urbanization on Body Size, Condition, and Physiology in an Urban Exploiter: A Multi-Component Approach. (United States)

    Meillère, Alizée; Brischoux, François; Parenteau, Charline; Angelier, Frédéric


    Consistent expanding urbanization dramatically transforms natural habitats and exposes organisms to novel environmental challenges, often leading to reduced species richness and diversity in cities. However, it remains unclear how individuals are affected by the urban environment and how they can or cannot adjust to the specific characteristics of urban life (e.g. food availability). In this study, we used an integrative multi-component approach to investigate the effects of urbanization on the nutritional status of house sparrows (Passer domesticus). We assessed several morphological and physiological indices of body condition in both juveniles (early post-fledging) and breeding adults from four sites with different levels of urbanization in France, Western Europe. We found that sparrows in more urbanized habitats have reduced body size and body mass compared to their rural conspecifics. However, we did not find any consistent differences in a number of complementary indices of condition (scaled mass index, muscle score, hematocrit, baseline and stress-induced corticosterone levels) between urban and rural birds, indicating that urban sparrows may not be suffering nutritional stress. Our results suggest that the urban environment is unlikely to energetically constrain adult sparrows, although other urban-related variables may constrain them. On the other hand, we found significant difference in juvenile fat scores, suggesting that food types provided to young sparrows differed highly between habitats. In addition to the observed smaller size of urban sparrows, these results suggest that the urban environment is inadequate to satisfy early-life sparrows' nutritional requirements, growth, and development. The urban environment may therefore have life-long consequences for developing birds.

  18. Influence of Urbanization on Body Size, Condition, and Physiology in an Urban Exploiter: A Multi-Component Approach (United States)

    Meillère, Alizée; Brischoux, François; Parenteau, Charline; Angelier, Frédéric


    Consistent expanding urbanization dramatically transforms natural habitats and exposes organisms to novel environmental challenges, often leading to reduced species richness and diversity in cities. However, it remains unclear how individuals are affected by the urban environment and how they can or cannot adjust to the specific characteristics of urban life (e.g. food availability). In this study, we used an integrative multi-component approach to investigate the effects of urbanization on the nutritional status of house sparrows (Passer domesticus). We assessed several morphological and physiological indices of body condition in both juveniles (early post-fledging) and breeding adults from four sites with different levels of urbanization in France, Western Europe. We found that sparrows in more urbanized habitats have reduced body size and body mass compared to their rural conspecifics. However, we did not find any consistent differences in a number of complementary indices of condition (scaled mass index, muscle score, hematocrit, baseline and stress-induced corticosterone levels) between urban and rural birds, indicating that urban sparrows may not be suffering nutritional stress. Our results suggest that the urban environment is unlikely to energetically constrain adult sparrows, although other urban-related variables may constrain them. On the other hand, we found significant difference in juvenile fat scores, suggesting that food types provided to young sparrows differed highly between habitats. In addition to the observed smaller size of urban sparrows, these results suggest that the urban environment is inadequate to satisfy early-life sparrows’ nutritional requirements, growth, and development. The urban environment may therefore have life-long consequences for developing birds. PMID:26270531

  19. Influence of Urbanization on Body Size, Condition, and Physiology in an Urban Exploiter: A Multi-Component Approach.

    Directory of Open Access Journals (Sweden)

    Alizée Meillère

    Full Text Available Consistent expanding urbanization dramatically transforms natural habitats and exposes organisms to novel environmental challenges, often leading to reduced species richness and diversity in cities. However, it remains unclear how individuals are affected by the urban environment and how they can or cannot adjust to the specific characteristics of urban life (e.g. food availability. In this study, we used an integrative multi-component approach to investigate the effects of urbanization on the nutritional status of house sparrows (Passer domesticus. We assessed several morphological and physiological indices of body condition in both juveniles (early post-fledging and breeding adults from four sites with different levels of urbanization in France, Western Europe. We found that sparrows in more urbanized habitats have reduced body size and body mass compared to their rural conspecifics. However, we did not find any consistent differences in a number of complementary indices of condition (scaled mass index, muscle score, hematocrit, baseline and stress-induced corticosterone levels between urban and rural birds, indicating that urban sparrows may not be suffering nutritional stress. Our results suggest that the urban environment is unlikely to energetically constrain adult sparrows, although other urban-related variables may constrain them. On the other hand, we found significant difference in juvenile fat scores, suggesting that food types provided to young sparrows differed highly between habitats. In addition to the observed smaller size of urban sparrows, these results suggest that the urban environment is inadequate to satisfy early-life sparrows' nutritional requirements, growth, and development. The urban environment may therefore have life-long consequences for developing birds.

  20. Science and society: different bioethical approaches towards animal experimentation. (United States)

    Brom, Frans W A


    The use of live animals for experiments plays an important role in many forms of research. This gives rise to an ethical dilemma. On the one hand, most of the animals used are sentient beings who may be harmed by the experiments. The research, on the other hand, may be vital for preventing, curing or alleviating human diseases. There is no consensus on how to tackle this dilemma. One extreme is the view taken by adherents of the so-called animal rights view. According to this view, we are never justified in harming animals for human purposes - however vital these purposes may be. The other extreme is the ruthless view, according to which animals are there to be used at our discretion. However, most people have a view situated somewhere between these two extremes. It is accepted that animals may be used for research - contrary to the animal rights view. However, contrary to the ruthless view, that is only accepted under certain conditions. The aim of this presentation is to present different ethical views which may serve as a foundation for specifying the circumstances under which it is acceptable to use animals for research. Three views serving this role are contractarianism, utilitarianism and a deontological approach. According to contractarianism, the key ethical issue is concern for the sentiments of other human beings in society, on whose co-operation those responsible for research depend. Thus it is acceptable to use animals as long as most people can see the point of the experiment and are not offended by the way it is done. According to utilitarianism, the key ethical issue is about the consequences for humans and animals. Thus it is justified to use animals for research if enough good comes out of it in terms of preventing suffering and creating happiness, and if there is no better alternative. In the deontological approach the prima facie duty of beneficence towards human beings has to be weighed against the prima facie duties not to harm animals and to


    Directory of Open Access Journals (Sweden)

    L. G. G. Rodrigues

    Full Text Available Abstract Air blast is one of the most employed industrial chilling methods. It can be enhanced, i.e., increasing heat transfer and reducing cooling time, by superficial evaporative phenomena. This work reports a methodology, including experimental setup and mathematical modelling, to quantify the air chilling enhancement by wetting the surface of the object to be chilled. A spherical metal model was covered by a cotton tissue (wet or dry and placed into a cold chamber. The effective heat transfer coefficient was determined at different temperature, air velocity, and relative humidity from time-temperature profiles into the sphere. Under the same air conditions, the effective coefficient between sphere and air was increased three-fold by moistening the cotton tissue on the sphere surface. Furthermore, comparing a dry and wet surface showed that evaporative cooling resulted in much shorter chilling times. The proposed approach was able to assess evaporative heat transfer by measuring only the time-temperature profile, and is suitable for industrial applications.

  2. Teachers' implicit personality theories about the gifted: an experimental approach. (United States)

    Baudson, Tanja Gabriele; Preckel, Franzis


    The implicit theories teachers hold about the gifted influence their perception of and behavior toward highly able students, thus impacting the latter's educational opportunities. Two persistent stereotypes about the gifted can be distinguished: the harmony hypothesis (gifted students are superior in almost all domains) and the disharmony hypothesis (giftedness implies maladaptive social behavior and emotional problems). The present study investigated whether teachers' implicit personality theories about the gifted are in line with the harmony or the disharmony hypothesis. Using an experimental vignette approach, we examined 321 prospective and practicing teachers' implicit personality theories (based on the big five personality framework) about students described along three dimensions (ability level, gender, and age, resulting in 8 different vignettes), controlling for teachers' age, gender, experience with gifted students, and knowledge about giftedness. Ability level had the strongest effect on teachers' ratings (partial η² = .60). Students described as gifted were perceived as more open to new experiences, more introverted, less emotionally stable, and less agreeable (all ps < .001). No differences were found for conscientiousness. Gender and its interaction with ability level had a small effect (partial η²s = .04 and .03). Thus, teachers' implicit personality theories about the gifted were in line with the disharmony hypothesis. Possible consequences for gifted identification and education are discussed. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  3. Mutations that Cause Human Disease: A Computational/Experimental Approach

    Energy Technology Data Exchange (ETDEWEB)

    Beernink, P; Barsky, D; Pesavento, B


    International genome sequencing projects have produced billions of nucleotides (letters) of DNA sequence data, including the complete genome sequences of 74 organisms. These genome sequences have created many new scientific opportunities, including the ability to identify sequence variations among individuals within a species. These genetic differences, which are known as single nucleotide polymorphisms (SNPs), are particularly important in understanding the genetic basis for disease susceptibility. Since the report of the complete human genome sequence, over two million human SNPs have been identified, including a large-scale comparison of an entire chromosome from twenty individuals. Of the protein coding SNPs (cSNPs), approximately half leads to a single amino acid change in the encoded protein (non-synonymous coding SNPs). Most of these changes are functionally silent, while the remainder negatively impact the protein and sometimes cause human disease. To date, over 550 SNPs have been found to cause single locus (monogenic) diseases and many others have been associated with polygenic diseases. SNPs have been linked to specific human diseases, including late-onset Parkinson disease, autism, rheumatoid arthritis and cancer. The ability to predict accurately the effects of these SNPs on protein function would represent a major advance toward understanding these diseases. To date several attempts have been made toward predicting the effects of such mutations. The most successful of these is a computational approach called ''Sorting Intolerant From Tolerant'' (SIFT). This method uses sequence conservation among many similar proteins to predict which residues in a protein are functionally important. However, this method suffers from several limitations. First, a query sequence must have a sufficient number of relatives to infer sequence conservation. Second, this method does not make use of or provide any information on protein structure, which

  4. Experimental Approach on the Cognitive Perception of Historical Urban Skyline

    Directory of Open Access Journals (Sweden)

    Seda H. Bostancı


    display of a skyline can be discussed through this experimental approach. This study aims to do experimental research among a group of architecture students who are strong at drawing and schematic expressions. The selected group of samples will be asked to draw (1 the schematic skyline images of the city they live in and a city they have visited as far as they remember, (2 examined how they draw a skyline and how much time it takes after they are shown a skyline of a historical city chosen in a certain time, (3 watch a video on the streets of two different cities they have seen or haven't seen before, and asked to draw a skyline of the city based on what they have watched. Finally, these different situations will be analyzed. In the experimental study, After 3 days, drawing the best remembered skyline image will be requested from students. And what the sample group have thought in this selection in terms of aesthetics will be measured with the semantic differential and the adjective pairs. Participants will be asked to draw the catchy image of the skyline shown in order to compare the experimental methods and the subjective aesthetic evaluation methods. Observation-based determinations will be realized by the analysis of these drawings and the adjective pairs. In this way, the relation between the skyline perception and the aesthetic experience in urban life will be discussed.

  5. Fluid-Solid Interaction and Multiscale Dynamic Processes: Experimental Approach (United States)

    Arciniega-Ceballos, Alejandra; Spina, Laura; Mendo-Pérez, Gerardo M.; Guzmán-Vázquez, Enrique; Scheu, Bettina; Sánchez-Sesma, Francisco J.; Dingwell, Donald B.


    . Analysis of time series, both experimental and synthetics, synchronized with high-speed imaging enables the explanation and interpretation of distinct phases of the dynamics of these fluids and the extraction of time and frequency characteristics of the individual processes. We observed that the effects of both, pressure drop triggering function and viscosity, control the characteristics of the micro-signals in time and frequency. This suggests the great potential that experimental and numerical approaches provide to untangle from field volcanic seismograms the multiscale processes of the stress field, driving forces and fluid-rock interaction that determine the volcanic conduit dynamics.

  6. Traditional and Modern Biomedical Prospecting: Part II-the Benefits: Approaches for a Sustainable Exploitation of Biodiversity (Secondary Metabolites and Biomaterials from Sponges). (United States)

    Müller, Werner E G; Schröder, Heinz C; Wiens, Matthias; Perović-Ottstadt, Sanja; Batel, Renato; Müller, Isabel M


    The progress in molecular and cell biology has enabled a rational exploitation of the natural resources of the secondary metabolites and biomaterials from sponges (phylum Porifera). It could be established that these natural substances are superior for biomedical application to those obtained by the traditional combinatorial chemical approach. It is now established that the basic structural and functional elements are highly conserved from sponges to the crown taxa within the Protostomia (Drosophila melanogaster and Caenorhabditis elegans) and Deuterostomia (human); therefore, it is obvious that the molecular etiology of diseases within the metazoan animals have a common basis. Hence, the major challenge for scientists studying natural product chemistry is to elucidate the target(s) of a given secondary metabolite, which is per se highly active and selective. After this step, the potential clinical application can be approached. The potential value of some selected secondary metabolites, all obtained from sponges and their associated microorganisms, is highlighted. Examples of compounds that are already in medical use (inhibition of tumor/virus growth [arabinofuranosyl cytosine and arabinofuranosyl adenine]), or are being considered as lead structures (acting as cytostatic and anti-inflammatory secondary metabolites [avarol/avarone], causing induction of apoptosis [sorbicillactone]) or as prototypes for the interference with metabolic pathways common in organisms ranging from sponges to humans (modulation of pathways activated by fungal components [aeroplysinin], inhibition of angiogenesis [2-methylthio-1,4-napthoquinone], immune modulating activity [FK506]) are discussed in this study. In addition, bioactive proteins from sponges are listed (antibacterial activity [pore-forming protein and tachylectin]). Finally, it is outlined that the skeletal elements-the spicules-serve as blueprints for new biomaterials, especially those based on biosilica, which might be

  7. Mechanical behaviour of the heel pad: experimental and numerical approach

    DEFF Research Database (Denmark)

    Matteoli, Sara; Fontanella, C. G.; Virga, A.

    The aim of the present work was to investigate the stress relaxation phenomena of the heel pad region under different loading conditions. A 31-year-old healthy female was enrolled in this study and her left foot underwent both MRI and experimental compression tests. Experimental results were...

  8. Herbal Medicines: from Traditional Medicine to Modern Experimental Approaches

    Directory of Open Access Journals (Sweden)

    Bahram Rasoulian


    Full Text Available Academic writings indicate that the medicinal use of plants dates back to 4000 - 5000 B.C. (1. Utilization of medicinal herbs has indeed a long history not only in human's life, but also in animals and there are some interesting evidences about the animals' self-medication, in both the prevention and treatment of diseases (2-5. The World Health Organization (WHO has recognized the importance of traditional medicines and created strategies, guidelines and standards for botanical medicines (6, 7. A significant part of those traditional text dealing with medicine, which were appreciated by ancient scientific communities worldwide, such as The Canon of Medicine by Persian physician–philosopher Ibn Sina (or Avicenna, 980 to 1032 AD, is allocated to herbal medicines. The Canon explores nearly 500 medicinal plants and herbal drugs. It should be noted that this book was used as a medical textbook in Europe until the 17th century AD (8, 9. Although there are important evidences about using some kinds of experimental approaches in traditional medicine (8, the efficacy of such approaches is in doubt because it is generally agreed that they might have been part of physicians' personal experiences. Not only the demand for herbal drugs is growing in developing countries, but also there are some evidences that consumers in developed countries are becoming disillusioned with modern healthcare; hence, the demand for traditional alternatives including herbal medicines is increasing in developing countries (10. On the one hand, the increased interest in herbal medicines throughout the world (10, 11, on the other hand, the need for direct empirical evidence about the effectiveness of herbal medicines in the proper statistical society with the appropriate number and method, denote the significance of new studies about medicinal plants and publishing their results. Herbal Medicines Journal (eISSN: 2538-2144 reports valuable research results for researchers all

  9. The Ethics of Exploitation

    Directory of Open Access Journals (Sweden)

    Paul McLaughlin


    Full Text Available Philosophical inquiry into exploitation has two major deficiencies to date: it assumes that exploitation is wrong by definition; and it pays too much attention to the Marxian account of exploitation. Two senses of exploitation should be distinguished: the ‘moral’ or pejorative sense and the ‘non-moral’ or ‘non-prejudicial’ sense. By demonstrating the conceptual inadequacy of exploitation as defined in the first sense, and by defining exploitation adequately in the latter sense, we seek to demonstrate the moral complexity of exploitation. We contend, moreover, that moral evaluation of exploitation is only possible once we abandon a strictly Marxian framework and attempt, in the long run, to develop an integral ethic along Godwinian lines.

  10. Exploiting diverse crowd-sourced data as part of a mixed-methods approach to validating modelled flood extents and dynamics (United States)

    Rollason, Edward; Bracken, Louise; Hardy, Richard; Large, Andy


    The use of flood models for evaluating flood risk from rivers and the sea is now a standard practice across Europe since the introduction of the 2007 EU Floods Directive requiring the assessment and mapping of flood risk from all major rivers and the sea. The availability of high quality topographic data from LiDAR and other remotely sensed sources has led to the increasing adoption of 2 dimensional models for simulating the dynamics of flooding on the floodplain. However, the ability to effectively validate dynamic floodplain inundation has not kept pace with the increasing complexity and spatial resolution of flood models. Validation remains dependent upon in-channel validation using flood level gauges or post-event data collection of wrack-marks, sometimes supplemented by community-derived anecdotal data. This poster presents the findings of a 'mixed-methods approach' to flood model validation using the winter 2016 floods on the River Tyne, UK. Using flood inundation results from a simple LISFLOOD-FP model of the River Tyne at Corbridge, the research develops a novel mixed-methods approach to validating both the maximum flood depths and extents, and the dynamics of the flood through the event. A crowd-sourced dataset of anecdotal information on flood dynamics, supported by photographic and video evidence, as well as community-derived, high definition UAV footage captured 24 and 48 hours after the peak of the event, allows for the comprehensive reconstruction of the flood dynamics and a more complete validation of the effectiveness of the model in reconstructing not just the maximum flood extent but also the dynamics of the rising and falling stages of an event. The findings of the research indicate the potential for making use of a much greater variety of locally-sourced data, particularly exploiting new technologies which offer opportunities for the collection of high quality data in the immediate aftermath of flooding events when traditional agencies may still

  11. Relative degradation of nuclear and mitochondrial DNA: an experimental approach. (United States)

    Foran, David R


    Single copy nuclear loci often cannot be amplified from degraded remains, necessitating the analysis of mitochondrial DNA (mtDNA). The success in analyzing mtDNA is generally thought to result from its higher copy number in the cell; however, other factors, such as cellular location or molecular features, may be equally or more important in the superior preservation of mtDNA. To explore and compare mtDNA and nuclear DNA degradation, mouse tissues (muscle, liver, and brain) were allowed to degrade at different temperatures, and the relative degradation of a mitochondrial gene, a single copy nuclear gene, and a multi-copy nuclear gene was assayed using real-time polymerase chain reaction. The tissues were also homogenized, allowing the three loci to degrade in the same cellular environment. Gene copy number and cellular location both influence DNA recovery. In some instances, multi-copy loci could be recovered when the single copy locus could not; however, the pattern of relative DNA degradation changed between whole and homogenized tissues. The overall results indicate that DNA degradation is influenced by multiple factors-including cellular location, chromatin structure, and transcriptional activity-factors that could be used to exploit loci for more robust forensic analysis from degraded biological material.

  12. In-Store Experimental Approach to Pricing and Consumer Behavior (United States)

    Sigurdsson, Valdimar; Foxall, Gordon; Saevarsson, Hugi


    This study assessed how, and to what extent, it is possible to use behavioral experimentation and relative sales analysis to study the effects of price on consumers' brand choices in the store environment. An in-store experiment was performed in four stores to investigate the effects of different prices of a target brand on consumers' relative…

  13. The Use of an Experimental Design Approach to Investigate the ...

    African Journals Online (AJOL)


    This study looked at using statistical design of experimental (DoE) principles to observe interactions between two graphite types and a nanocarbon ... Pb-acid battery, Pb-plate, graphite, expanders, design of experiment. 1. Introduction .... The CCA test was done by placing the cells in a freezer for 24 h at –18 ± 1 °C prior to ...

  14. Comparison as an Approach to the Experimental Method (United States)

    Turner, David A.


    In his proposal for comparative education, Marc Antoinne Jullien de Paris argues that the comparative method offers a viable alternative to the experimental method. In an experiment, the scientist can manipulate the variables in such a way that he or she can see any possible combination of variables at will. In comparative education, or in…

  15. Raman spectroscopy: a novel experimental approach to evaluating renal tumours. (United States)

    Bensalah, Karim; Fleureau, Julien; Rolland, Denis; Lavastre, Olivier; Rioux-Leclercq, Nathalie; Guillé, François; Patard, Jean-Jacques; Senhadji, Lotfi; de Crevoisier, Renaud


    New optical techniques of spectroscopy have shown promising results in the evaluation of solid tumours. To evaluate the potential of Raman spectroscopy (RS) to assess renal tumours at surgery. Over a 5-mo period, Raman optical spectra were prospectively acquired on surgical renal specimens removed due to suspicion of cancer. Raman measures were normalised to ensure comparison between spectra. A lower resolution signal was computed using a wavelet decomposition procedure to diminish the size of the signal and exploit the complete spectrum. A support vector machine (SVM) with a linear kernel and a sequential minimal optimisation solver was applied. A leave-one-out cross-validation technique was used to train and test the SVM. There were 36 patients with 34 malignant tumours (27 clear-cell, 6 papillary, and 1 chromophobe) and 2 benign (1 oncocytoma and 1 metanephric cyst) tumours. A total of 241 analysable Raman spectra were obtained. The SVM was able to classify tumoural and normal tissue with an accuracy of 84% (sensitivity 82%, specificity 87%). High-grade and low-grade tumours were differentiated with a precision of 82% (sensitivity 84%, specificity 80%). Histologic subtype could be categorised with an accuracy of 93% (sensitivity 96%, specificity 87%). SVM could not be applied to classify benign and malignant tumours because of the restricted number of benign spectra. RS can accurately differentiate normal and tumoural renal tissue, low-grade and high-grade renal tumours, and histologic subtype of renal cell carcinoma. Larger prospective studies are needed to confirm these preliminary data. Copyright 2010 European Association of Urology. Published by Elsevier B.V. All rights reserved.

  16. A cyber-physical approach to experimental fluid mechanics (United States)

    Mackowski, Andrew Williams

    This Thesis documents the design, implementation, and use of a novel type of experimental apparatus, termed Cyber-Physical Fluid Dynamics (CPFD). Unlike traditional fluid mechanics experiments, CPFD is a general-purpose technique that allows one to impose arbitrary forces on an object submerged in a fluid. By combining fluid mechanics with robotics, we can perform experiments that would otherwise be incredibly difficult or time-consuming. More generally, CPFD allows a high degree of automation and control of the experimental process, allowing for much more efficient use of experimental facilities. Examples of CPFD's capabilites include imposing a gravitational force in the horizontal direction (allowing a test object to "fall" sideways in a water channel), simulating nonlinear springs for a vibrating fluid-structure system, or allowing a self-propelled body to move forward under its own force. Because experimental parameters (including forces and even the mass of the test object) are defined in software, one can define entire ensembles of experiments to run autonomously. CPFD additionally integrates related systems such as water channel speed control, LDV flow speed measurements, and PIV flowfield measurements. The end result is a general-purpose experimental system that opens the door to a vast array of fluid-structure interaction problems. We begin by describing the design and implementation of CPFD, the heart of which is a high-performance force-feedback control system. Precise measurement of time-varying forces (including removing effects of the test object's inertia) is more critical here than in typical robotic force-feedback applications. CPFD is based on an integration of ideas from control theory, fluid dynamics, computer science, electrical engineering, and solid mechanics. We also describe experiments using the CPFD experimental apparatus to study vortex-induced vibration (VIV) and oscillating-airfoil propulsion. We show how CPFD can be used to simulate

  17. Biobetters From an Integrated Computational/Experimental Approach

    Directory of Open Access Journals (Sweden)

    Serdar Kuyucak


    Full Text Available Biobetters are new drugs designed from existing peptide or protein-based therapeutics by improving their properties such as affinity and selectivity for the target epitope, and stability against degradation. Computational methods can play a key role in such design problems—by predicting the changes that are most likely to succeed, they can drastically reduce the number of experiments to be performed. Here we discuss the computational and experimental methods commonly used in drug design problems, focusing on the inverse relationship between the two, namely, the more accurate the computational predictions means the less experimental effort is needed for testing. Examples discussed include efforts to design selective analogs from toxin peptides targeting ion channels for treatment of autoimmune diseases and monoclonal antibodies which are the fastest growing class of therapeutic agents particularly for cancers and autoimmune diseases.

  18. Impact of instructional approach on students' epistemologies about experimental physics

    CERN Document Server

    Wilcox, Bethany R


    Student learning in undergraduate physics laboratory courses has garnered increased attention within the PER community. Considerable work has been done to develop curricular materials and pedagogical techniques designed to enhance student learning within laboratory learning environments. Examples of these transformation efforts include the Investigative Science Learning Environment (ISLE), Modeling Instruction, and integrated lab/lecture environments (e.g., studio physics). In addition to improving students' understanding of the physics content, lab courses often have an implicit or explicit goal of increasing students' understanding and appreciation of the nature of experimental physics. We examine students' responses to a laboratory-focused epistemological assessment -- the Colorado Learning Attitudes about Science Survey for Experimental Physics (E-CLASS) -- to explore whether courses using transformed curricula or pedagogy show more expert-like student epistemologies relative to courses using traditional ...

  19. Biobetters From an Integrated Computational/Experimental Approach


    Kuyucak, Serdar; Kayser, Veysel


    Biobetters are new drugs designed from existing peptide or protein-based therapeutics by improving their properties such as affinity and selectivity for the target epitope, and stability against degradation. Computational methods can play a key role in such design problems?by predicting the changes that are most likely to succeed, they can drastically reduce the number of experiments to be performed. Here we discuss the computational and experimental methods commonly used in drug design probl...

  20. Experimental workflow for developing a feed forward strategy to control biomass growth and exploit maximum specific methane productivity of Methanothermobacter marburgensis in a biological methane production process (BMPP

    Directory of Open Access Journals (Sweden)

    Alexander Krajete


    Full Text Available Recently, interests for new biofuel generations allowing conversion of gaseous substrate(s to gaseous product(s arose for power to gas and waste to value applications. An example is biological methane production process (BMPP with Methanothermobacter marburgensis. The latter, can convert carbon dioxide (CO2 and hydrogen (H2, having different origins and purities, to methane (CH4, water and biomass. However, these gas converting bioprocesses are tendentiously gas limited processes and the specific methane productivity per biomass amount (qCH4 tends to be low. Therefore, this contribution proposes a workflow for the development of a feed forward strategy to control biomass, growth (rx and qCH4 in a continuous gas limited BMPP. The proposed workflow starts with a design of experiment (DoE to optimize media composition and search for a liquid based limitation to control selectively growth. From the DoE it came out that controlling biomass growth was possible independently of the dilution and gassing rate applied while not affecting methane evolution rates (MERs. This was done by shifting the process from a natural gas limited state to a controlled liquid limited growth. The latter allowed exploiting the maximum biocatalytic activity for methane formation of Methanothermobacter marburgensis. An increase of qCH4 from 42 to 129 mmolCH4 g−1 h−1 was achieved by applying a liquid limitation compare with the reference state. Finally, a verification experiment was done to verify the feeding strategy transferability to a different process configuration. This evidenced the ratio of the fed KH2PO4 to rx (R(FKH2PO4/rx has an appropriate parameter for scaling feeds in a continuous gas limited BMPP. In the verification experiment CH4 was produced in a single bioreactor step at a methane evolution rate (MER of   132 mmolCH4*L−1*h−1 at a CH4 purity of 93 [Vol.%].

  1. Image exploitation for MISAR (United States)

    Heinze, N.; Edrich, M.; Saur, G.; Krüger, W.


    The miniature SAR-system MiSAR has been developed by EADS Germany for lightweight UAVs like the LUNASystem. MiSAR adds to these tactical UAV-systems the all-weather reconnaissance capability, which is missing until now. Unlike other SAR sensors, that produce large strip maps at update rates of several seconds, MiSAR generates sequences of SAR images with approximately 1 Hz frame rate. photo interpreters (PI) of tactical drones, now mainly experienced with visual interpretation, are not used to SARimages, especially not with SAR-image sequence characteristics. So they should be supported to improve their ability to carry out their task with a new, demanding sensor system. We have therefore analyzed and discussed with military PIs in which task MiSAR can be used and how the PIs can be supported by special algorithms. We developed image processing- and exploitation-algorithms for such SAR-image sequences. A main component is the generation of image sequence mosaics to get more oversight. This mosaicing has the advantage that also non straight /linear flight-paths and varying squint angles can be processed. Another component is a screening-component for manmade objects to mark regions of interest in the image sequences. We use a classification based approach, which can be easily adapted to new sensors and scenes. These algorithms are integrated into an image exploitation system to improve the image interpreters ability to get a better oversight, better orientation and helping them to detect relevant objects, especially considering long endurance reconnaissance missions.

  2. From integrated control to integrated farming, an experimental approach

    NARCIS (Netherlands)

    Vereijken, P.H.


    Integrated control or integrated pest management (IPM), as envisaged originally, is not being practised to any large extent in arable farming, notwithstanding considerable research efforts. The reasons for this are discussed. A more basic approach called integrated farming is suggested. Preliminary

  3. The impact of loneliness on paranoia: An experimental approach. (United States)

    Lamster, Fabian; Nittel, Clara; Rief, Winfried; Mehl, Stephanie; Lincoln, Tania


    Loneliness is a common problem in patients with schizophrenia, and may be particularly linked with persecutory ideation. Nevertheless, its role as a potential risk factor in the formation and maintenance of persecutory delusions is largely unexplored. Loneliness was experimentally manipulated using a false-feedback paradigm in a non-clinical sample (n = 60). Change in state paranoia was compared between the induction of increased loneliness, the induction of reduced loneliness and a control condition. Distinct associations between pre-post scores of loneliness and state paranoia were examined at three (medium/high/low) levels of proneness to psychosis across the experimental conditions. Reduction of loneliness was associated with a significant reduction of present paranoid beliefs, while induction of loneliness lead to more pronounced paranoia on trend significance level. Moreover, proneness to psychosis significantly moderated the impact of loneliness on paranoia. Persons with a pronounced level of proneness to psychosis showed a stronger reduction of paranoid beliefs as a consequence of a decrease in loneliness, than less prone individuals. A limitation is the small size of our sample, which may have limited the power to detect significant within-group changes in state paranoia in the high-loneliness condition and changes in loneliness in the low-loneliness condition. The findings support the feasibility of the experimental design to manipulate loneliness and suggest that loneliness could be a cause of paranoia. However, the findings need to be confirmed in high risk samples to draw conclusions about the role of loneliness in the genesis of clinically relevant levels of paranoia and derive implications for cognitive behaviour therapy. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. A systems-based food safety evaluation: an experimental approach. (United States)

    Higgins, Charles L; Hartfield, Barry S


    Food establishments are complex systems with inputs, subsystems, underlying forces that affect the system, outputs, and feedback. Building on past exploration of the hazard analysis critical control point concept and Ludwig von Bertalanffy General Systems Theory, the National Park Service (NPS) is attempting to translate these ideas into a realistic field assessment of food service establishments and to use information gathered by these methods in efforts to improve food safety. Over the course of the last two years, an experimental systems-based methodology has been drafted, developed, and tested by the NPS Public Health Program. This methodology is described in this paper.

  5. Target Localization with a Single Antenna via Directional Multipath Exploitation

    Directory of Open Access Journals (Sweden)

    Ali H. Muqaibel


    Full Text Available Target localization in urban sensing can benefit from angle dependency of the pulse shape at a radar receiver antenna. We propose a localization approach that utilizes the embedded directivity in ultra-wideband (UWB antennas to estimate target positions. A single radar unit sensing operation of indoor targets surrounded by interior walls is considered, where interior wall multipaths are exploited to provide target cross-range. This exploitation assumes resolvability of the multipath components, which is made possible by the virtue of using UWB radar signals. The proposed approach is most attractive when only few multipaths are detectable due to propagation obstructions or owing to low signal-to-noise ratios. Both simulated and experimental data are used to demonstrate the effectiveness of the proposed approach.

  6. Exploitability Assessment with TEASER (United States)


    exploits. We saw this as an advantage of our dataset because we had to confirm that either a bug was exploitable or not exploitable. For the 28 CHAPTER 5...corruption which demonstrates that there is very little activity within c-ares to take advantage of after the heap corruption. This idea is in line with the...remote code execution POCs. 42 Bibliography [1] Analyze crashes to find security vulnerabilities in your apps . https: //

  7. Anthropology of sexual exploitation

    Directory of Open Access Journals (Sweden)

    Lalić Velibor


    Full Text Available In this paper, the authors observe sexual exploitation from an anthropological perspective. They analyze the rational, ethical, emotional and mythological dimensions of human sexuality. Consequently, after setting the phenomenon in a social and historical context, sexual exploitation is closely observed in the contemporary age. Based on thoughts of relevant thinkers, they make the conclusion that the elimination of sexual exploitation is not an utterly legal issue, but political and economical issues as well. Namely, legal norms are not sufficient to overcome sexual exploitation, but, political and economical relationships in contemporary societies, which will be based on sincere equal opportunities must be established.

  8. Unilateral robotic hybrid mini-maze: a novel experimental approach. (United States)

    Moslemi, Mohammad; Rawashdeh, Badi; Meyer, Mark; Nguyen, Duy; Poston, Robert; Gharagozloo, Farid


    A complete Cox maze IV procedure is difficult to accomplish using current endoscopic and minimally invasive techniques. These techniques are hampered by inability to adequately dissect the posterior structures of the heart and place all necessary lesions. We present a novel approach, using robotic technology, that achieves placement of all the lesions of the complete maze procedure. In three cadaveric human models, the technical feasibility of using robotic instruments through the right chest to dissect the posterior structures of the heart and place all Cox maze lesions was performed. The entire posterior aspect of the heart was dissected in the cadaveric model facilitating successful placement of all Cox maze IV lesions with robotic assistance through minimally invasive incisions. The robotic Cox maze IV procedure through the novel right thoracic approach is feasible. This obviates the need for sternotomy and avoids the associated morbidity of the conventional Cox-maze procedure. Copyright © 2015 John Wiley & Sons, Ltd.

  9. Improving attitudes toward brands with environmental associations: an experimental approach


    Montoro-R??os, Francisco J.; Luque Mart??nez, Teodoro; Fuentes Moreno, Francisca; Ca??adas Soriano, Paloma


    Purpose ??? The purpose of this article is to determine the relative importance of the ecological attribute when other attributes referring to the functional performance of a brand are taken into account, and check the effectiveness of environmental labels. Design/methodology/approach ??? The paper establishes an experiment in which 352 women responsible for the household shopping are exposed to different levels of environmental information. The study analyses the effect said information ...

  10. Caloric intake and Alzheimer's disease. Experimental approaches and therapeutic implications. (United States)

    Pasinetti, Giulio Maria; Zhao, Zhong; Qin, Weiping; Ho, Lap; Shrishailam, Yemul; Macgrogan, Donal; Ressmann, Wendy; Humala, Nelson; Liu, Xunxian; Romero, Carmen; Stetka, Breton; Chen, Linghong; Ksiezak-Reding, Hanna; Wang, Jun


    Alzheimer's disease (AD) is a rapidly growing public health concern with potentially devastating effects. Presently, there are no known cures or effective preventive strategies. While genetic factors are relevant in early-onset cases, they appear to play less of a role in late-onset sporadic AD cases, the most common form of AD. Due to the fact that the disease typically strikes very late in life, delaying symptoms could be as good as a cure for many people. For example, it is now widely accepted that if the onset of the disease could be delayed by even 5 years, the incidence could be cut in half. Both clinical and epidemiological evidence suggests that modification of lifestyle factors such as nutrition may prove crucial to AD management given the mounting experimental evidence suggesting that brain cells are remarkably responsive to "what somebody is doing". Among other nongenetic factors influencing AD, recent studies strongly support the evidence that caloric intake may play a role in the relative risk for AD clinical dementia. Indeed, the effect of diet in AD has been an area of research that has produced promising results, at least experimentally. Most importantly, as mechanistic pathways are defined and their biochemical functions scrutinized, the evidence supporting a direct link between nutrition and AD neuropathology continues to grow. Our work, as well as that of others, has recently resulted in the development of experimental dietary regimens that might promote, attenuate or even reverse features of AD. Most remarkably, while we found that high caloric intake based on saturated fat promotes AD type Beta-amyloidosis, conversely we found that dietary restriction based on reduced carbohydrate intake is able to prevent it. This evidence is very exciting and is, in part, consistent with current epidemiological studies suggesting that obesity and diabetes are associated with a >4-fold increased risk of developing AD. The clarification of the mechanisms

  11. Polyelectrolyte gels in electric fields: a theoretical and experimental approach (United States)

    Guelch, Rainer W.; Holdenried, Jens; Weible, Andrea; Wallmersperger, Thomas; Kroeplin, Bernd


    In order to gain more insight into basic principles of the nature of polymer hydrogels which are able to execute work by large deformations in electric fields, this study is mainly focused on those gels with a polyacrylamide backbone being very suitable for considerably varying their physicochemical properties simply by specific copolymerization. In the experimental part, the Donnan potential has been registered for the first time in PAAm/PAA gels in varying electric fields and different chemical environments with a new microelectrode technique. The mechanical properties of the gels have been characterized by measurements of swelling ratio, elastic modulus and being in dynamics under various stimuli. In the theoretical part, a model based both on this theory and the measured mechanical parameters, the bending dynamics of a polyelectrolyte gel in an electric field can be evaluated. Numerical simulations employing finite element discretization demonstrate the potential and the validity of the model. A promising correlation between theory and experiment could be shown.

  12. A Novel Approach to Experimental Studies of Mineral Dissolution Kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Chen Zhu; William E. Seyfried


    Currently, DOE is conducting pilot CO{sub 2} injection tests to evaluate the concept of geological sequestration. One strategy that potentially enhances CO{sub 2} solubility and reduces the risk of CO{sub 2} leak back to the surface is dissolution of indigenous minerals in the geological formation and precipitation of secondary carbonate phases, which increases the brine pH and immobilizes CO{sub 2}. Clearly, the rates at which these dissolution and precipitation reactions occur directly determine the efficiency of this strategy. However, one of the fundamental problems in modern geochemistry is the persistent two to five orders of magnitude discrepancy between laboratory-measured and field derived feldspar dissolution rates. To date, there is no real guidance as to how to predict silicate reaction rates for use in quantitative models. Current models for assessment of geological carbon sequestration have generally opted to use laboratory rates, in spite of the dearth of such data for compositionally complex systems, and the persistent disconnect between lab and field applications. Therefore, a firm scientific basis for predicting silicate reaction kinetics in CO{sub 2} injected geological formations is urgently needed to assure the reliability of the geochemical models used for the assessments of carbon sequestration strategies. The funded experimental and theoretical study attempts to resolve this outstanding scientific issue by novel experimental design and theoretical interpretation to measure silicate dissolution rates and iron carbonate precipitation rates at conditions pertinent to geological carbon sequestration. In the first year of the project, we have successfully developed a sample preparation method and completed three batch feldspar dissolution experiments at 200 C and 300 bars. The changes of solution chemistry as dissolution experiments progressed were monitored with on-line sampling of the aqueous phase at the constant temperature and pressure

  13. Flowability of granular materials with industrial applications - An experimental approach (United States)

    Torres-Serra, Joel; Romero, Enrique; Rodríguez-Ferran, Antonio; Caba, Joan; Arderiu, Xavier; Padullés, Josep-Manel; González, Juanjo


    Designing bulk material handling equipment requires a thorough understanding of the mechanical behaviour of powders and grains. Experimental characterization of granular materials is introduced focusing on flowability. A new prototype is presented which performs granular column collapse tests. The device consists of a channel whose design accounts for test inspection using visualization techniques and load measurements. A reservoir is attached where packing state of the granular material can be adjusted before run-off to simulate actual handling conditions by fluidisation and deaeration of the pile. Bulk materials on the market, with a wide range of particle sizes, can be tested with the prototype and the results used for classification in terms of flowability to improve industrial equipment selection processes.

  14. Impact of drilling fluids on seagrasses: an experimental community approach

    Energy Technology Data Exchange (ETDEWEB)

    Morton, R.D.; Duke, T.W.; Macauley, J.M.; Clark, J.R.; Price, W.A.


    Effects of a used drilling fluid on an experimental seagrass community (Thalassia testudinum) were measured by exposing the community to the suspended particulate phase (SPP) in laboratory microcosms. Structure of the macroinvertebrate assemblage, growth and chlorophyll content of grass and associated epiphytes, and rates of decomposition as indicated by weight loss of grass leaves in treated and untreated microcosms were compared. There were statistically significant differences in community structure and function among untreated microcosms and those receiving the clay and drilling fluid. For example, drilling fluid and clay caused a significant loss in the number of the ten most numerically abundant (dominant) macroinvertebrates, and drilling fluid decreased the rate at which Thalassia leaves decomposed.

  15. Oxidative Damage and Suppression: an Experimental Approach to Teaching Biochemistry

    Directory of Open Access Journals (Sweden)

    Isa G. J. de Avellar


    Full Text Available Experimental Biochemistry is a challenging and worthy didactical  task:  a vast field with many different techniques.   Radical mediated biooxidative processes, implied in aging and accompanying various pathologies,  have an enormous  appeal  to public in general and particularly to students in the science field.   The  Fenton  reaction,   first  reported by  the 22-year  old Cambridge  chemistry  undergraduate Henry J. H. Fenton  (Chemical  news vol. 33 page 190, 1876, is a useful in vitro system for generating hydroxyl radicals generally implied in biooxidation.  When coupled with the 2-deoxyribose (DR- thiobarbituric acid (TBA  method,  provides  a most  resourceful  tool for studying  oxidative  processes that may  provide  insights  to  in  vivo  processes.    In  this  communication  a  classical  experiment of quantification of thiobarbituric reactive  substances  (TBARS resulting  from breakage  of DR (5 mM in aqueous buffered media (5mM, pH 7.2 by 0,100 mM H2O2 and ferrous ion (up to 0,150 mM is the base for the demonstration of oxidative damage suppressive ability of known hydroxyl radical quenchers as ethanol,  dimethylsulfoxide (DMSO  and  thiourea (1mM  each.   The  results  of the  experiments, developed  to  be worked  in experimental classes for senior  undergraduate biochemistry students of biomedical  sciences, show a very mild but  consistent  suppressive  capacity  for ethanol  (reduction in2 percent  of TBARS  measured  at  0,150 mM ferrous ion concentration.  Thiourea  and  DMSO show very similar  suppressive  abilities:  reduction  in 19 and  18 percent  in measured  TBARS,  respectively (at  0,150 mM ferrous ion.


    Directory of Open Access Journals (Sweden)

    Ivan Cotman


    Full Text Available The processes of forming, petrography, features, properties and exploitation of granite boulders are described. The directional drilling and black powder blasting is the succesful method in exploitation of granite boulders (boulder technology (the paper is published in Croatian.

  17. Charge Transport in LDPE Nanocomposites Part I—Experimental Approach

    Directory of Open Access Journals (Sweden)

    Anh T. Hoang


    Full Text Available This work presents results of bulk conductivity and surface potential decay measurements on low-density polyethylene and its nanocomposites filled with uncoated MgO and Al2O3, with the aim to highlight the effect of the nanofillers on charge transport processes. Material samples at various filler contents, up to 9 wt %, were prepared in the form of thin films. The performed measurements show a significant impact of the nanofillers on reduction of material’s direct current (dc conductivity. The investigations thus focused on the nanocomposites having the lowest dc conductivity. Various mechanisms of charge generation and transport in solids, including space charge limited current, Poole-Frenkel effect and Schottky injection, were utilized for examining the experimental results. The mobilities of charge carriers were deduced from the measured surface potential decay characteristics and were found to be at least two times lower for the nanocomposites. The temperature dependencies of the mobilities were compared for different materials.

  18. [Statistical Process Control applied to viral genome screening: experimental approach]. (United States)

    Reifenberg, J M; Navarro, P; Coste, J


    During the National Multicentric Study concerning the introduction of NAT for HCV and HIV-1 viruses in blood donation screening which was supervised by the Medical and Scientific departments of the French Blood Establishment (Etablissement français du sang--EFS), Transcription-Mediated transcription Amplification (TMA) technology (Chiron/Gen Probe) was experimented in the Molecular Biology Laboratory of Montpellier, EFS Pyrénées-Méditerranée. After a preliminary phase of qualification of the material and training of the technicians, routine screening of homologous blood and apheresis donations using this technology was applied for two months. In order to evaluate the different NAT systems, exhaustive daily operations and data were registered. Among these, the luminescence results expressed as RLU of the positive and negative calibrators and the associated internal controls were analysed using Control Charts, Statistical Process Control methods, which allow us to display rapidly process drift and to anticipate the appearance of incidents. This study demonstrated the interest of these quality control methods, mainly used for industrial purposes, to follow and to increase the quality of any transfusion process. it also showed the difficulties of the post-investigations of uncontrolled sources of variations of a process which was experimental. Such tools are in total accordance with the new version of the ISO 9000 norms which are particularly focused on the use of adapted indicators for processes control, and could be extended to other transfusion activities, such as blood collection and component preparation.

  19. Placebo and Nocebo Effects in Sexual Medicine: An Experimental Approach. (United States)

    Kruger, Tillmann H C; Grob, Carolin; de Boer, Claas; Peschel, Thomas; Hartmann, Uwe; Tenbergen, Gilian; Schedlowski, Manfred


    Few studies have investigated placebo and nocebo effects in a human sexuality context. Studying placebo and nocebo responses in this context may provide insight into their potential to modulate sexual drive and function. To examine such effects in sexual medicine, 48 healthy, male heterosexual participants were divided into four groups. Each group received instruction to expect stimulating effects, no effect, or an inhibitory effect on sexual functions. Only one group received the dopamine agonist cabergoline; all other groups received placebo or nocebo. Modulations in sexual experience were examined through an established experimental paradigm of sexual arousal and masturbation-induced orgasm during erotic film sequences with instruction to induce placebo or nocebo effects. Endocrine data, appetitive, consummatory, and refractory sexual behavior parameters were assessed using the Arizona Sexual Experience Scale (ASEX) and the Acute Sexual Experience Scale (ASES). Results showed increased levels of sexual function after administration of cabergoline with significant effects for several parameters. Placebo effects were induced only to a small degree. No negative effects on sexual parameters in the nocebo condition were noted. This paradigm could induce only small placebo and nocebo effects. This supports the view that healthy male sexual function seems relatively resistant to negative external influences.

  20. Experimental Economics on Firm’s Behavior: Entry Game Approach

    Directory of Open Access Journals (Sweden)

    I Wayan Sukadana


    Full Text Available The paper analyzes subject’s behavior in evolutionary process of entry game. The experiment is designed to analyze the behavior of the subject. The experiment is set in sequential entry games. Process of the game was conducted under asymmetric information, uncertainty, payoff perturbation and random matching. The subjects of the experiment were students of the Universitas Udayana, Bali, Indonesia. Subjects who play as new-entrance firms tend to choose “stay-out” strategy when the uncertainty and the amount of loss increase. Meanwhile, the subjects who play as an incumbent firm, which set to have more information about the game (market rather than the new-entrances, most of the time abuse their position by choose “threat” strategy, which not a credible strategy for some of them. Experimental studies shows that New-entrance tend to weight more on lost when the risk increase (from risk averse setting to risk seeking setting, and tend to choose sure value over a lotteries although the expected value from lotteries is higher or the same. These findings support the reason that Indonesian youngsters tend to choose a job as a PNS or employee of existing firms. The results also support the reason that Indonesian businessman is more willing to open a new business if they have a guarantee for their losses.

  1. Redox buffer capacity of the cell: theoretical and experimental approach. (United States)

    Martinovich, Grigory G; Martinovich, Irina V; Cherenkevich, Sergey N; Sauer, Heinrich


    Reactive oxygen species (ROS) are involved in a variety of biological phenomena, such as mutation, carcinogenesis, inflammation, aging, development, and signal transduction. Intracellular generation of ROS might lead to the activation of redox signaling or oxidative stress. Nonetheless, it is difficult to estimate whether ROS-induced intracellular events are beneficial or deleterious to the cell. The quantitative basis of changes in the intracellular redox state of cells is not well-defined, thus leading to the dilemma that redox changes induced by oxidants in distinct cell types cannot be predicted. To overcome this limitation this study undertakes to analyze on a theoretical as well as on an experimental basis the intracellular redox state changes occurring inside cells upon addition of oxidants or reductants. 2,7-Dichlorodihydrofluorescein (H(2)DCF) was used to characterize the redox buffer capacity in erythrocytes. It was shown that the redox buffer capacity of erythrocytes in the relation to peroxynitrite (ONOO(-)) is 2.1 times lower than the redox buffer capacity of erythrocytes in the relation to hydrogen peroxide (H(2)O(2)). The feasibility of redox buffer capacity assessment as an innovative tool for investigation and description of redox signaling events in cells is discussed.

  2. An experimental approach to the percolation of sticky nanotubes. (United States)

    Vigolo, B; Coulon, C; Maugey, M; Zakri, C; Poulin, P


    Percolation is a statistical concept that describes the formation of an infinite cluster of connected particles or pathways. Lowering the percolation threshold is a critical issue to achieve light and low-cost conductive composites made of an insulating matrix loaded with conductive particles. This has interest for applications where charge dissipation and electrical conductivity are sought in films, coatings, paints, or composite materials. One route to decreasing the loading required for percolation is to use rod-like particles. Theoretical predictions indicate that this may also be achieved by altering the interaction potential between the particles. Although percolation may not always respond monotonically to interactions, the use of adhesive rods can be expected to be an ideal combination. By using a system made of carbon nanotubes in an aqueous surfactant solution, we find that very small attraction can markedly lower the percolation threshold. The strength of this effect can thereby have direct technological interest and explain the large variability of experimental results in the literature dealing with the electrical behavior of composites loaded with conducting rods.

  3. Functional complexity and ecosystem stability: an experimental approach

    Energy Technology Data Exchange (ETDEWEB)

    Van Voris, P.; O' Neill, R.V.; Shugart, H.H.; Emanuel, W.R.


    The complexity-stability hypothesis was experimentally tested using intact terrestrial microcosms. Functional complexity was defined as the number and significance of component interactions (i.e., population interactions, physical-chemical reactions, biological turnover rates) influenced by nonlinearities, feedbacks, and time delays. It was postulated that functional complexity could be nondestructively measured through analysis of a signal generated from the system. Power spectral analysis of hourly CO/sub 2/ efflux, from eleven old-field microcosms, was analyzed for the number of low frequency peaks and used to rank the functional complexity of each system. Ranking of ecosystem stability was based on the capacity of the system to retain essential nutrients and was measured by net loss of Ca after the system was stressed. Rank correlation supported the hypothesis that increasing ecosystem functional complexity leads to increasing ecosystem stability. The results indicated that complex functional dynamics can serve to stabilize the system. The results also demonstrated that microcosms are useful tools for system-level investigations.

  4. Photodynamic therapy: Theoretical and experimental approaches to dosimetry (United States)

    Wang, Ken Kang-Hsin

    Singlet oxygen (1O2) is the major cytotoxic species generated during photodynamic therapy (PDT), and 1O 2 reactions with biological targets define the photodynamic dose at the most fundamental level. We have developed a theoretical model for rigorously describing the spatial and temporal dynamics of oxygen (3O 2) consumption and transport and microscopic 1O 2 dose deposition during PDT in vivo. Using experimentally established physiological and photophysical parameters, the mathematical model allows computation of the dynamic variation of hemoglobin-3O 2 saturation within vessels, irreversible photosensitizer degradation due to photobleaching, therapy-induced blood flow decrease and the microscopic distributions of 3O2 and 1O 2 dose deposition under various irradiation conditions. mTHPC, a promising photosensitizer for PDT, is approved in Europe for the palliative treatment of head and neck cancer. Using the theoretical model and informed by intratumor sensitizer concentrations and distributions, we calculated photodynamic dose depositions for mTHPC-PDT. Our results demonstrate that the 1O 2 dose to the tumor volume does not track even qualitatively with long-term tumor responses. Thus, in this evaluation of mTHPC-PDT, any PDT dose metric that is proportional to singlet oxygen creation and/or deposition would fail to predict the tumor response. In situations like this one, other reporters of biological response to therapy would be necessary. In addition to the case study of mTHPC-PDT, we also use the mathematical model to simulate clinical photobleaching data, informed by a possible blood flow reduction during treatment. In a recently completed clinical trial at Roswell Park Cancer Institute, patients with superficial basal cell carcinoma received topical application of 5-aminolevulinic acid (ALA) and were irradiated with 633 nm light at 10-150 mW cm-2 . Protoporphyrin IX (PpIX) photobleaching in the lesion and the adjacent perilesion normal margin was monitored by

  5. Experimental Approaches to Study Genome Packaging of Influenza A Viruses. (United States)

    Isel, Catherine; Munier, Sandie; Naffakh, Nadia


    The genome of influenza A viruses (IAV) consists of eight single-stranded negative sense viral RNAs (vRNAs) encapsidated into viral ribonucleoproteins (vRNPs). It is now well established that genome packaging (i.e., the incorporation of a set of eight distinct vRNPs into budding viral particles), follows a specific pathway guided by segment-specific cis-acting packaging signals on each vRNA. However, the precise nature and function of the packaging signals, and the mechanisms underlying the assembly of vRNPs into sub-bundles in the cytoplasm and their selective packaging at the viral budding site, remain largely unknown. Here, we review the diverse and complementary methods currently being used to elucidate these aspects of the viral cycle. They range from conventional and competitive reverse genetics, single molecule imaging of vRNPs by fluorescence in situ hybridization (FISH) and high-resolution electron microscopy and tomography of budding viral particles, to solely in vitro approaches to investigate vRNA-vRNA interactions at the molecular level.

  6. Experimental Approaches to Study Genome Packaging of Influenza A Viruses

    Directory of Open Access Journals (Sweden)

    Catherine Isel


    Full Text Available The genome of influenza A viruses (IAV consists of eight single-stranded negative sense viral RNAs (vRNAs encapsidated into viral ribonucleoproteins (vRNPs. It is now well established that genome packaging (i.e., the incorporation of a set of eight distinct vRNPs into budding viral particles, follows a specific pathway guided by segment-specific cis-acting packaging signals on each vRNA. However, the precise nature and function of the packaging signals, and the mechanisms underlying the assembly of vRNPs into sub-bundles in the cytoplasm and their selective packaging at the viral budding site, remain largely unknown. Here, we review the diverse and complementary methods currently being used to elucidate these aspects of the viral cycle. They range from conventional and competitive reverse genetics, single molecule imaging of vRNPs by fluorescence in situ hybridization (FISH and high-resolution electron microscopy and tomography of budding viral particles, to solely in vitro approaches to investigate vRNA-vRNA interactions at the molecular level.

  7. Examples of feedback, experimental and theoretical approaches for concrete durability assessment


    Toutlemonde F.; Le Pape Y.; Lion M; Jeanpierre A.


    This paper presents some experimental data obtained from UHPFRC (Ultra-High Performance Fibre-Reinforced Concrete) being exposed for 10 years in a cooling tower and a high slag content concrete being exposed for 30 years in a marine environment. Experimental data are then used for assessing concrete durability through a theoretical approach, namely performance-based analysis. The results from the application of this approach are consistent with the penetration depth of aggressive agents measu...

  8. Web based learning support for experimental design in molecular biology: a top-down approach

    NARCIS (Netherlands)

    Aegerter-Wilmsen, T.; Hartog, R.; Bisseling, T.


    An important learning goal of a molecular biology curriculum is the attainment of a certain competence level in experimental design. Currently, undergraduate students are confronted with experimental approaches in textbooks, lectures and laboratory courses. However, most students do not reach a

  9. Web-Based Learning Support for Experimental Design in Molecular Biology: A Top-Down Approach (United States)

    Aegerter-Wilmsen, Tinri; Hartog, Rob; Bisseling, Ton


    An important learning goal of a molecular biology curriculum is the attainment of a certain competence level in experimental design. Currently, undergraduate students are confronted with experimental approaches in textbooks, lectures and laboratory courses. However, most students do not reach a satisfactory level of competence in the designing of…

  10. Network exploitation using WAMI tracks (United States)

    Rimey, Ray; Record, Jim; Keefe, Dan; Kennedy, Levi; Cramer, Chris


    Creating and exploiting network models from wide area motion imagery (WAMI) is an important task for intelligence analysis. Tracks of entities observed moving in the WAMI sensor data are extracted, then large numbers of tracks are studied over long time intervals to determine specific locations that are visited (e.g., buildings in an urban environment), what locations are related to other locations, and the function of each location. This paper describes several parts of the network detection/exploitation problem, and summarizes a solution technique for each: (a) Detecting nodes; (b) Detecting links between known nodes; (c) Node attributes to characterize a node; (d) Link attributes to characterize each link; (e) Link structure inferred from node attributes and vice versa; and (f) Decomposing a detected network into smaller networks. Experimental results are presented for each solution technique, and those are used to discuss issues for each problem part and its solution technique.

  11. An efficient approach to bioconversion kinetic model generation based on automated microscale experimentation integrated with model driven experimental design

    DEFF Research Database (Denmark)

    Chen, B. H.; Micheletti, M.; Baganz, F.


    design. It incorporates a model driven approach to the experimental design that minimises the number of experiments to be performed, while still generating accurate values of kinetic parameters. The approach has been illustrated with the transketolase mediated asymmetric synthesis of L......Reliable models of enzyme kinetics are required for the effective design of bioconversion processes. Kinetic expressions of the enzyme-catalysed reaction rate however, are frequently complex and establishing accurate values of kinetic parameters normally requires a large number of experiments....... These can be both time consuming and expensive when working with the types of non-natural chiral intermediates important in pharmaceutical syntheses. This paper presents ail automated microscale approach to the rapid and cost effective generation of reliable kinetic models useful for bioconversion process...

  12. Personal Reflections on Observational and Experimental Research Approaches to Childhood Psychopathology (United States)

    Rapoport, Judith L.


    The past 50 years have seen dramatic changes in childhood psychopathology research. The goal of this overview is to contrast observational and experimental research approaches; both have grown more complex such that the boundary between these approaches may be blurred. Both are essential. Landmark observational studies with long-term follow-up…

  13. Synergistic Integration of Experimental and Simulation Approaches for the de Novo Design of Silk-Based Materials. (United States)

    Huang, Wenwen; Ebrahimi, Davoud; Dinjaski, Nina; Tarakanova, Anna; Buehler, Markus J; Wong, Joyce Y; Kaplan, David L


    Tailored biomaterials with tunable functional properties are crucial for a variety of task-specific applications ranging from healthcare to sustainable, novel bio-nanodevices. To generate polymeric materials with predictive functional outcomes, exploiting designs from nature while morphing them toward non-natural systems offers an important strategy. Silks are Nature's building blocks and are produced by arthropods for a variety of uses that are essential for their survival. Due to the genetic control of encoded protein sequence, mechanical properties, biocompatibility, and biodegradability, silk proteins have been selected as prototype models to emulate for the tunable designs of biomaterial systems. The bottom up strategy of material design opens important opportunities to create predictive functional outcomes, following the exquisite polymeric templates inspired by silks. Recombinant DNA technology provides a systematic approach to recapitulate, vary, and evaluate the core structure peptide motifs in silks and then biosynthesize silk-based polymers by design. Post-biosynthesis processing allows for another dimension of material design by controlled or assisted assembly. Multiscale modeling, from the theoretical prospective, provides strategies to explore interactions at different length scales, leading to selective material properties. Synergy among experimental and modeling approaches can provide new and more rapid insights into the most appropriate structure-function relationships to pursue while also furthering our understanding in terms of the range of silk-based systems that can be generated. This approach utilizes nature as a blueprint for initial polymer designs with useful functions (e.g., silk fibers) but also employs modeling-guided experiments to expand the initial polymer designs into new domains of functional materials that do not exist in nature. The overall path to these new functional outcomes is greatly accelerated via the integration of

  14. Comparison between numerical models and CHENSI with experimental data (MUST within the case of the 0° approach flow.

    Directory of Open Access Journals (Sweden)

    Medjahed Bendida


    Full Text Available The MUST wind tunnel data set served as a validation case for obstacle-resolving micro-scale models in the COST Action 732 “Quality Assurance and Improvement of Micro-Scale Meteorological Models”.The code used for the numerical simulation is code CHENSI, simulations carried out showed a certain degree of agreement between the experimental results and those of the numerical simulation, they highlight the need for proceeding to an experimental campaign but with more measurements and the need for having a good control of determining factors in the exploitation of its results. The aim is to explain the experimental data obtained by atmospheric wind on the physical model. The site company of Mock Urban Setting Test (MUST was selected to be simulated by the code CEN CHENSI developed by the team of Dynamique of l’atmosphere Habitee of LME/ECN. The code was based on (K- ε model of (Launder and Spalding. For the integration of the PDE (Potential Dimensional equations constitute the mathematical model, the finite volume method of (Ferziger and Peric was used within the decade disposition of unknowns MAC of (Harlow and Welck for the discretisation of PDE terms. The boundary conditions were imposed according to the wall laws (In ground and on buildings or within Dirichlet condition (Inlet boundary or of Newman (Outlet boundary or top limit. The numerical domain used was comparable to the one of the atmospheric wind experiences within a three-dimensional Cartesian mesh. Numerical results presented in this study for the mean flow field, turbulent kinetic energy in the direction of wind incidence 0°. For an objective comparison of the CHENSI model performances within other European codes used for MUST configuration simulation. The results obtained by the numerical modelling approach are presented in this paper.

  15. Shape Design of the Duct for Tidal Converters Using Both Numerical and Experimental Approaches (pre-2015

    Directory of Open Access Journals (Sweden)

    Chul H. Jo


    Full Text Available Recently, focus has been placed on ocean energy resources because environmental concerns regarding the exploitation of hydrocarbons are increasing. Among the various ocean energy sources, tidal current power (TCP is recognized as the most promising energy source in terms of predictability and reliability. The enormous energy potential in TCP fields has been exploited by installing TCP systems. The flow velocity is the most important factor for power estimation of a tidal current power system. The kinetic energy of the flow is proportional to the cube of the flow’s velocity, and velocity is a critical variable in the performance of the system. Since the duct can accelerate the flow velocity, its use could expand the applicable areas of tidal devices to relatively low velocity sites. The inclined angle of the duct and the shapes of inlet and outlet affect the acceleration rates of the flow inside the duct. In addition, the volume of the duct can affect the flow velocity amplification performance. To investigate the effects of parameters that increase the flow velocity, a series of simulations are performed using the commercial computational fluid dynamics (CFD code ANSYS-CFX. Experimental investigations were conducted using a circulation water channel (CWC.

  16. Experimentation on accuracy of non functional requirement prioritization approaches for different complexity projects

    Directory of Open Access Journals (Sweden)

    Raj Kumar Chopra


    Full Text Available Non functional requirements must be selected for implementation together with functional requirements to enhance the success of software projects. Three approaches exist for performing the prioritization of non functional requirements using the suitable prioritization technique. This paper performs experimentation on three different complexity versions of the industrial software project using cost-value prioritization technique employing three approaches. Experimentation is conducted to analyze the accuracy of individual approaches and the variation of accuracy with the complexity of the software project. The results indicate that selecting non functional requirements separately, but in accordance with functionality has higher accuracy amongst the other two approaches. Further, likewise other approaches, it witnesses the decrease in accuracy with increase in software complexity but the decrease is minimal.

  17. Behavior changes and binding communication for Mediterranean littoral preservation. Controlling variables with an experimental approach

    Directory of Open Access Journals (Sweden)

    Anne BILLER


    Full Text Available The action-research Ecogestes aimed at improving the communication strategy used by the « ambassadors of the sea » to promote Mediterranean littoral preservation behaviors among sea users. With an experimental approach, a new methodology was devised and its impact was evaluated. Throughout the presentation of this action-research, we will illustrate the way researchers chose to control experimental variables and reduce noise in observed effects.

  18. An Experimental Approach to the Joint Effects of Relations with Partner, Friends and Parents on Happiness (United States)

    Theuns, P.; Verresen, N.; Mairesse, O.; Goossens, R.; Michiels, L.; Peeters, E.; Wastiau, M.


    Personal relations constitute an important life domain and satisfaction therein affects happiness in people. In an experimental approach with a 3x3x3 vignettes study in which 103 first year psychology students participated, the contribution of the quality of relationships with parents, friends, and a partner are studied. It is found that the…

  19. Experimental semiotics: a new approach for studying communication as a form of joint action. (United States)

    Galantucci, Bruno


    In the last few years, researchers have begun to investigate the emergence of novel forms of human communication in the laboratory. I survey this growing line of research, which may be called experimental semiotics, from three distinct angles. First, I situate the new approach in its theoretical and historical context. Second, I review a sample of studies that exemplify experimental semiotics. Third, I present an empirical study that illustrates how the new approach can help us understand the socio-cognitive underpinnings of human communication. The main conclusion of the paper will be that, by reproducing micro samples of historical processes in the laboratory, experimental semiotics offers new powerful tools for investigating human communication as a form of joint action. Copyright © 2009 Cognitive Science Society, Inc.

  20. Viruses exploiting peroxisomes. (United States)

    Lazarow, Paul B


    Viruses that are of great importance for global public health, including HIV, influenza and rotavirus, appear to exploit a remarkable organelle, the peroxisome, during intracellular replication in human cells. Peroxisomes are sites of lipid biosynthesis and catabolism, reactive oxygen metabolism, and other metabolic pathways. Viral proteins are targeted to peroxisomes (the spike protein of rotavirus) or interact with peroxisomal proteins (HIV's Nef and influenza's NS1) or use the peroxisomal membrane for RNA replication. The Nef interaction correlates strongly with the crucial Nef function of CD4 downregulation. Viral exploitation of peroxisomal lipid metabolism appears likely. Mostly, functional significance and mechanisms remain to be elucidated. Recently, peroxisomes were discovered to play a crucial role in the innate immune response by signaling the presence of intracellular virus, leading to the first rapid antiviral response. This review unearths, interprets and connects old data, in the hopes of stimulating new and promising research. Copyright © 2011. Published by Elsevier Ltd.

  1. Dissemination and Exploitation Strategy

    DEFF Research Database (Denmark)

    Badger, Merete; Monaco, Lucio; Fransson, Torsten

    The research infrastructure project Virtual Campus Hub (VCH) runs from October 1, 2011 to September 30, 2013. Four technical universities in Europe, who are all active in the field of sustainable energy, form the project consortium: the Technical University of Denmark, The Royal Institute...... of Technology in Sweden, Politecnico di Torino in Italy, and Eindhoven University of Technology in the Netherlands. The project is partially funded by the European Commission under the 7th Framework Programme (project no. RI-283746). This report describes the final dissemination and exploitation strategy...... for project Virtual Campus Hub. A preliminary dissemination and exploitation plan was setup early in the project as described in the deliverable D6.1 Dissemination strategy paper - preliminary version. The plan has been revised on a monthly basis during the project’s lifecycle in connection with the virtual...

  2. Towards A New Approach For Arabic Root Extraction:Exploit Relations Between The Word Letters And Their Placement In The Word For Arabic Root Extraction

    Directory of Open Access Journals (Sweden)

    Fatma Abu Hawas


    Full Text Available In this paper we present a new root-extraction approach for Arabic words. The approach tries to assign for Arabic word a unique root without having a database of word roots, a list of words patterns or even a list of all the prefixes and the suffixes of the Arabic words. Unlike most of Arabic rule-based stemmers, it tries to predict the letters positions that may form the word root one by one using some rules based on the relations among the Arabic word letters and their placement in the word. This paper will focus on two parts of the approach. The first one deals with the rules that distinguish between the Arabic definite article “ال -AL” and the permanent component “ال -AL” that may found in any Arabic word. The second part of the approach adopts the segmentation of the word into three parts and classifies Arabic letters in to groups according to their positions in each segment. The proposed approach is a system composed of several modules that corporate together to extract the word root. The approach has been tested and evaluated using the Holy Quran words. The results of the evaluation show a promising root extraction algorithm.

  3. Personal reflections on observational and experimental research approaches to childhood psychopathology. (United States)

    Rapoport, Judith L


    The past 50 years have seen dramatic changes in childhood psychopathology research. The goal of this overview is to contrast observational and experimental research approaches; both have grown more complex such that the boundary between these approaches may be blurred. Both are essential. Landmark observational studies with long-term follow-up (Robins, 1966; Yarrow, Campbell, & Burton, 1970) have had - and continue to have - unique impact on clinical research and practice. Epidemiological studies showed high rates of psychological disorder and their close tie to neurological impairment (Rutter, Tizard, & Whitemore, 1970). These studies have current impact with respect to brain imaging correlates of clinical outcome. Pharmacological studies, particularly those on stimulants and on treatment of pediatric obsessive compulsive disorder (OCD), have propelled experimental methodology and inspired translational approaches. Predicted future trends are: more informed subgrouping of our heterogeneous phenotypes, reliance on multicenter trials, and documentation of non-conventional methods of care delivery.

  4. An innovative approach for planning and execution of pre-experimental runs for Design of Experiments

    Directory of Open Access Journals (Sweden)

    Muhammad Arsalan Farooq


    Full Text Available This paper addresses the study of the pre-experimental planning phase of the Design of Experiments (DoE in order to improve the final product quality. The pre-experimental planning phase includes a clear identification of the problem statement, selection of control factors and their respective levels and ranges. To improve production quality based on the DoE a new approach for the pre-experimental planning phase, called Non-Conformity Matrix (NCM, is presented. This article also addresses the key steps of the pre-experimental runs considering a consumer goods manufacturing process. Results of the application for an industrial case show that this methodology can support a clear definition of the problem and also a correct identification of the factor ranges in particular situations. The proposed new approach allows modeling the entire manufacturing system holistically and correctly defining the factor ranges and respective levels for a more effective application of DoE. This new approach can be a useful resource for both research and industrial practitioners who are dedicated to large DoE projects with unknown factor interactions, when the operational levels and ranges are not completely defined.

  5. Hacking the art of exploitation

    CERN Document Server

    Erickson, Jon


    A comprehensive introduction to the techniques of exploitation and creative problem-solving methods commonly referred to as "hacking," Hacking: The Art of Exploitation is for both technical and non-technical people who are interested in computer security. It shows how hackers exploit programs and write exploits, instead of just how to run other people's exploits. Unlike many so-called hacking books, this book explains the technical aspects of hacking, including stack based overflows, heap based overflows, string exploits, return-into-libc, shellcode, and cryptographic attacks on 802.11b.

  6. Competing Discourses about Youth Sexual Exploitation in Canadian News Media. (United States)

    Saewyc, Elizabeth M; Miller, Bonnie B; Rivers, Robert; Matthews, Jennifer; Hilario, Carla; Hirakata, Pam


    Media holds the power to create, maintain, or break down stigmatizing attitudes, which affect policies, funding, and services. To understand how Canadian news media depicts the commercial sexual exploitation of children and youth, we examined 835 Canadian newspaper articles from 1989-2008 using a mixed methods critical discourse analysis approach, comparing representations to existing research about sexually exploited youth. Despite research evidence that equal rates of boys and girls experience exploitation, Canadian news media depicted exploited youth predominantly as heterosexual girls, and described them alternately as victims or workers in a trade, often both in the same story. News media mentioned exploiters far less often than victims, and portrayed them almost exclusively as male, most often called 'customers' or 'consumers,' and occasionally 'predators'; in contrast, research has documented the majority of sexually exploited boys report female exploiters. Few news stories over the past two decades portrayed the diversity of victims, perpetrators, and venues of exploitation reported in research. The focus on victims but not exploiters helps perpetuate stereotypes of sexual exploitation as business or a 'victimless crime,' maintains the status quo, and blurs responsibility for protecting youth under the UN Convention on the Rights of the Child. Health care providers and researchers can be advocates for accuracy in media coverage about sexual exploitation; news reporters and editors should focus on exploiters more than victims, draw on existing research evidence to avoid perpetuating stereotypes, and use accurate terms, such as commercial sexual exploitation, rather than terms related to business or trade.

  7. [Improving methodical approaches to experimental studies in the field of occupational medicine]. (United States)

    Rukavishnikov, V S; Sosedova, L M


    The features of the methodical approaches in performing the experimental studies dealing with studying the working condition and the health state in the employees are presented in this paper. The results of our experiments performed in the Institute based on modeling the occupational toxic encephalopathy, studying the combined factor activity of the biological and chemical nature developing the methodical approaches to the assessment of the biological activity effects of the nanomaterials are indicated. The purposefulness of performing the experiments in the occupational medicine using the non-breedy and line-breedy animals is considered.

  8. Study of Photovoltaic Energy Storage by Supercapacitors through Both Experimental and Modelling Approaches

    Directory of Open Access Journals (Sweden)

    Pierre-Olivier Logerais


    Full Text Available The storage of photovoltaic energy by supercapacitors is studied by using two approaches. An overview on the integration of supercapacitors in solar energy conversion systems is previously provided. First, a realized experimental setup of charge/discharge of supercapacitors fed by a photovoltaic array has been operated with fine data acquisition. The second approach consists in simulating photovoltaic energy storage by supercapacitors with a faithful and accessible model composed of solar irradiance evaluation, equivalent electrical circuit for photovoltaic conversion, and a multibranch circuit for supercapacitor. Both the experimental and calculated results are confronted, and an error of 1% on the stored energy is found with a correction largely within ±10% of the transmission line capacitance according to temperature.

  9. Comparing Conventional Bank Credit Vis A Vis Shariah Bank Musharakah: Experimental Economic Approach

    Directory of Open Access Journals (Sweden)

    Muhamad Abduh


    Full Text Available Central Bank of Indonesia with dual banking system – i.e Shariah and Conventional Bank – keep on developing system that considered as an answer to generate the national economic growth. One of the banking activities that emphasized by the Central Bank of Indonesia is fund distribution through either conventional bank credit or shariah bank fi nancing. Having the Experimental Economic Approach based on Induced Value Theory and employing ANOVA, this paper found that shariah bank musharakah fi nancing system would come up with higher profi t opportunity compare to conventional credit system. One main reason is that musharakah fi nancing in shariah bank applies profi t and lost sharing (PLS scheme so that will not be a burden to the customer when he fi nd low profi t.Keywords: Credit Loan, Musharakah Financing, Induced Value Theory, Experimental Economic Approach, Analysis of Variance (ANOVA.

  10. Conceptual Approach for Precise Relative Positioning with Miniaturized GPS Loggers and Experimental Results (United States)


    Approach for Precise Relative Positioning with Miniaturized GPS Loggers and Experimental Results ( ) min 1 2 =∑ = m j jf (20) jbijbij DDf Φ−Φ...residual based test statistic: ( ) jnnjnnj m j j DDf m f Φ−Φ= − ≈ −− =∑ ˆ~ 1 RMS ,1,1 1 2 f (35) For sampling rates of 1 Hz or higher, ( )fRMS is very

  11. Integrated experimental and computational approach to laser machining of structural bone. (United States)

    Dahotre, Narendra B; Santhanakrishnan, Soundarapandian; Joshi, Sameehan S; Khan, Riaz J K; Fick, Daniel P; Robertson, William B; Sheh, Raymond K; Ironside, Charlie N


    This study describes the fundamentals of laser-bone interaction during bone machining through an integrated experimental-computational approach. Two groups of laser machining parameters identified the effects of process thermodynamics and kinetics on machining attributes at micro to macro. A continuous wave Yb-fiber Nd:YAG laser (wavelength 1070 nm) with fluences in the range of 3.18 J/mm 2 -8.48 J/mm 2 in combination of laser power (300 W-700 W) and machining speed (110 mm/s-250 mm/s) were considered for machining trials. The machining attributes were evaluated through scanning electron microscopy observations and compared with finite element based multiphysics-multicomponent computational model predicted values. For both groups of laser machining parameters, experimentally evaluated and computationally predicted depths and widths increased with increased laser energy input and computationally predicted widths remained higher than experimentally measured widths whereas computationally predicted depths were slightly higher than experimentally measured depths and reversed this trend for the laser fluence >6 J/mm 2 . While in both groups, the machining rate increased with increased laser fluence, experimentally derived machining rate remained lower than the computationally predicted values for the laser fluences lower than ∼4.75 J/mm 2 for one group and ∼5.8 J/mm 2 for other group and reversed in this trend thereafter. The integrated experimental-computational approach identified the physical processes affecting machining attributes. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

  12. Comparison of repulsive interatomic potentials calculated with an all-electron DFT approach with experimental data (United States)

    Zinoviev, A. N.; Nordlund, K.


    The interatomic potential determines the nuclear stopping power in materials. Most ion irradiation simulation models are based on the universal Ziegler-Biersack-Littmark (ZBL) potential (Ziegler et al., 1983), which, however, is an average and hence may not describe the stopping of all ion-material combinations well. Here we consider pair-specific interatomic potentials determined experimentally and by density-functional theory simulations with DMol approach (DMol software, 1997) to choose basic wave functions. The interatomic potentials calculated using the DMol approach demonstrate an unexpectedly good agreement with experimental data. Differences are mainly observed for heavy atom systems, which suggests they can be improved by extending a basis set and more accurately considering the relativistic effects. Experimental data prove that the approach of determining interatomic potentials from quasielastic scattering can be successfully used for modeling collision cascades in ion-solids collisions. The data obtained clearly indicate that the use of any universal potential is limited to internuclear distances R < 7 af (af is the Firsov length).

  13. Targeting druggable enzymome by exploiting natural medicines: An in silico-in vitro integrated approach to combating multidrug resistance in bacterial infection. (United States)

    Zang, Ping; Gong, Aijie; Zhang, Peirong; Yu, Jinling


    Antibiotic resistance is a major clinical and public health problem. Development of new therapeutic approaches to prevent bacterial multidrug resistance during antimicrobial chemotherapy has thus been becoming a primary consideration in the medicinal chemistry community. We described a new strategy that combats multidrug resistance by using natural medicines to target the druggable enzymome (i.e., enzymatic proteome) of Staphylococcus aureus. A pipeline of integrating in silico analysis and in vitro assay was purposed to identify antibacterial agents from a large library of natural products with diverse structures, high drug-likeness, and relatively low flexibility, with which a systematic interactome of 826 natural product candidates with 125 functionally essential S. aureus enzymes was constructed via a high-throughput cross-docking approach. The obtained docking score matrix was then converted into an array of synthetic scores; each corresponds to a natural product candidate. By systematically examining the docking results, a number of highly promising candidates with potent antibacterial activity were suggested. Three natural products, i.e., radicicol, jorumycin, and amygdalin, have been determined to possess strong broad-spectrum potency combating both the drug-resistant and drug-sensitive strains (MIC value products such as tetrandrine, bilobalide, and arbutin exhibited selective inhibition on different strains. Combined quantum mechanics/molecular mechanics analysis revealed diverse non-bonded interactions across the complex interfaces of newly identified antibacterial agents with their putative targets GyrB ATPase and tyrosyl-tRNA synthetase.

  14. Dimensional approaches to designing better experimental ecosystems: a practitioners guide with examples. (United States)

    Petersen, John E; Englund, Göran


    Enclosed, experimental ecosystems ("mesocosms") are now widely used research tools in ecology. However, the small size, short duration and often simplified biological and physical complexity of mesocosm experiments raises questions about extrapolating results from these miniaturized ecosystems to nature. Dimensional analysis, a technique widely used in engineering to create scale models, employs "compensatory distortion" as a means of maintaining functional similarity in properties and relationships of interest. An earlier paper outlined a general approach to applying dimensional analysis to the construction and interpretation of mesocosm experiments (Petersen and Hastings in Am Nat 157:324, 2001). In this paper we use examples, largely drawn from the aquatic literature, to illustrate how dimensional approaches might be used to maintain key ecological properties. Such key properties include effective habitat size, environmental variability, vertical and horizontal gradients, and interactions among habitats. We distinguish both continuous and discrete approaches that can be used to achieve functional similarity through compensatory distortion. In addition to its potential as a tool for improving the realism of experimental ecosystems, the dimensional approach points towards new options for developing, testing and advancing our understanding of scaling relationships in nature.

  15. A rational approach towards development of amorphous solid dispersions: Experimental and computational techniques. (United States)

    Chakravarty, Paroma; Lubach, Joseph W; Hau, Jonathan; Nagapudi, Karthik


    The purpose of this study was to determine the drug-polymer miscibility of GENE-A, a Genentech molecule, and hydroxypropyl methylcellulose-acetate succinate (HPMC-AS), a polymer, using computational and experimental approaches. The Flory-Huggins interaction parameter,χ, was obtained by calculating the solubility parameters for GENE-A and HPMC-AS over the temperature range of 25-100°C to obtain the free energy of mixing at different drug loadings (0-100%) using the Materials Studio modeling and simulation platform (thermodynamic approach). Solid-state nuclear magnetic spectroscopy (ssNMR) was used to measure the proton relaxation times for both drug and polymer at different drug loadings (up to 60%) at RT (kinetic approach). Thermodynamically, the drug and polymer were predicted to show favorable mixing as indicated by a negative Gibbs free energy of mixing from 25 to 100°C. ssNMR showed near identical relaxation times for both drug and polymer in the solid dispersion at RT and 40°C for a period up to 6 months showing phase mixing between the API and polymer on <10nm scale. Orthogonal computational and experimental approaches indicate phase mixing of the system components. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. The Geohazards Exploitation Platform (United States)

    Laur, Henri; Casu, Francesco; Bally, Philippe; Caumont, Hervé; Pinto, Salvatore


    The Geohazards Exploitation Platform, or Geohazards TEP (GEP), is an ESA originated R&D activity of the EO ground segment to demonstrate the benefit of new technologies for large scale processing of EO data. This encompasses on-demand processing for specific user needs, systematic processing to address common information needs of the geohazards community, and integration of newly developed processors for scientists and other expert users. The platform supports the geohazards community's objectives as defined in the context of the International Forum on Satellite EO and Geohazards organised by ESA and GEO in Santorini in 2012. The GEP is a follow on to the Supersites Exploitation Platform (SSEP) an ESA initiative to support the Geohazards Supersites & Natural Laboratories initiative (GSNL). Today the GEP allows to exploit 70+ Terabyte of ERS and ENVISAT archive and the Copernicus Sentinel-1 data available on line. The platform has already engaged 22 European early adopters in a validation activity initiated in March 2015. Since September, this validation has reached 29 single user projects. Each project is concerned with either integrating an application, running on demand processing or systematically generating a product collection using an application available in the platform. The users primarily include 15 geoscience centres and universities based in Europe: British Geological Survey (UK), University of Leeds (UK), University College London (UK), ETH University of Zurich (CH), INGV (IT), CNR-IREA and CNR-IRPI (IT), University of L'Aquila (IT), NOA (GR), Univ. Blaise Pascal & CNRS (FR), Ecole Normale Supérieure (FR), ISTERRE / University of Grenoble-Alpes (FR). In addition, there are users from Africa and North America with the University of Rabat (MA) and the University of Miami (US). Furthermore two space agencies and four private companies are involved: the German Space Research Centre DLR (DE), the European Space Agency (ESA), Altamira Information (ES

  17. Exploitative Learning by Exporting

    DEFF Research Database (Denmark)

    Golovko, Elena; Lopes Bento, Cindy; Sofka, Wolfgang

    Decisions on entering foreign markets are among the most challenging but also potentially rewarding strategy choices managers can make. In this study, we examine the effect of export entry on the firm investment decisions in two activities associated with learning about new technologies...... and learning about new markets ? R&D investments and marketing investments, in search of novel insights into the content and process underlying learning by exporting. We draw from organizational learning theory for predicting changes in both R&D and marketing investment patterns that accompany firm entry......, it is predominantly the marketing-related investment decisions associated with starting to export that lead to increases in firm productivity. We conclude that learning-by-exporting might be more properly characterized as ?learning about and exploiting new markets? rather than ?learning about new technologies...

  18. Conference on "Multidisciplinary approaches to nutritional problems". Postgraduate Symposium. Exploiting dietary supplementation trials to assess the impact of the prenatal environment on CVD risk. (United States)

    Hawkesworth, Sophie


    Animal studies have demonstrated that altering the maternal diet during pregnancy affects offspring disease risk. Data from human subjects on the early-life determinants of disease have been derived primarily from birth-weight associations; studies of the impact of the maternal diet are scarce and inconsistent. Investigating CVD risk factors in the offspring of women who have participated in maternal supplementation trials provides a useful resource in this research field, by virtue of employing an experimental design (as compared with observational studies). To date, follow-up studies have been published only for a small number of trials; these trials include the impact of maternal protein-energy, multiple-micronutrient and Ca supplementation on offspring disease risk. In Nepal maternal micronutrient supplementation has been shown to be associated with lower offspring systolic blood pressure at 2 years of age. Data from Guatemala on a pre- and postnatal protein-energy community intervention have suggested long-term improvements in fasting glucose and body composition but not in blood pressure. In The Gambia no association has been found between prenatal protein-energy supplementation and markers of CVD risk including body composition, blood pressure and fasting glucose and insulin in childhood and adolescence. Little evidence of an effect of maternal Ca supplementation on offspring blood pressure has been demonstrated in four trials, although the risk of high systolic blood pressure was found to be reduced in one trial. The present paper reviews the current evidence relating maternal nutritional supplementation during pregnancy to offspring CVD risk and explores the potential explanations for the lack of association.

  19. Approaches to experimental validation of high-temperature gas-cooled reactor components

    Energy Technology Data Exchange (ETDEWEB)

    Belov, S.E. [Joint Stock Company ' Afrikantov OKB Mechanical Engineering' , Burnakovsky Proezd, 15, Nizhny Novgorod 603074 (Russian Federation); Borovkov, M.N., E-mail: [Joint Stock Company ' Afrikantov OKB Mechanical Engineering' , Burnakovsky Proezd, 15, Nizhny Novgorod 603074 (Russian Federation); Golovko, V.F.; Dmitrieva, I.V.; Drumov, I.V.; Znamensky, D.S.; Kodochigov, N.G. [Joint Stock Company ' Afrikantov OKB Mechanical Engineering' , Burnakovsky Proezd, 15, Nizhny Novgorod 603074 (Russian Federation); Baxi, C.B.; Shenoy, A.; Telengator, A. [General Atomics, 3550 General Atomics Court, CA (United States); Razvi, J., E-mail: [General Atomics, 3550 General Atomics Court, CA (United States)


    Highlights: Black-Right-Pointing-Pointer Computational and experimental investigations of thermal and hydrodynamic characteristics for the equipment. Black-Right-Pointing-Pointer Vibroacoustic investigations. Black-Right-Pointing-Pointer Studies of the electromagnetic suspension system on GT-MHR turbo machine rotor models. Black-Right-Pointing-Pointer Experimental investigations of the catcher bearings design. - Abstract: The special feature of high-temperature gas-cooled reactors (HTGRs) is stressed operating conditions for equipment due to high temperature of the primary circuit helium, up to 950 Degree-Sign C, as well as acoustic and hydrodynamic loads upon the gas path elements. Therefore, great significance is given to reproduction of real operation conditions in tests. Experimental investigation of full-size nuclear power plant (NPP) primary circuit components is not practically feasible because costly test facilities will have to be developed for the power of up to hundreds of megawatts. Under such conditions, the only possible process to validate designs under development is representative tests of smaller scale models and fragmentary models. At the same time, in order to take in to validated account the effect of various physical factors, it is necessary to ensure reproduction of both individual processes and integrated tests incorporating needed integrated investigations. Presented are approaches to experimental validation of thermohydraulic and vibroacoustic characteristics for main equipment components and primary circuit path elements under standard loading conditions, which take account of their operation in the HTGR. Within the framework of the of modular helium reactor project, including a turbo machine in the primary circuit, a new and difficult problem is creation of multiple-bearing flexible vertical rotor. Presented are approaches to analytical and experimental validation of the rotor electromagnetic bearings, catcher bearings, flexible rotor

  20. Mechanistic insight into degradation of endocrine disrupting chemical by hydroxyl radical: An experimental and theoretical approach. (United States)

    Xiao, Ruiyang; Gao, Lingwei; Wei, Zongsu; Spinney, Richard; Luo, Shuang; Wang, Donghong; Dionysiou, Dionysios D; Tang, Chong-Jian; Yang, Weichun


    Advanced oxidation processes (AOPs) based on formation of free radicals at ambient temperature and pressure are effective for treating endocrine disrupting chemicals (EDCs) in waters. In this study, we systematically investigated the degradation kinetics of bisphenol A (BPA), a representative EDC by hydroxyl radical (OH) with a combination of experimental and theoretical approaches. The second-order rate constant (k) of BPA with OH was experimentally determined to be 7.2 ± 0.34 × 10(9) M(-1) s(-1) at pH 7.55. We also calculated the thermodynamic and kinetic behaviors for the bimolecular reactions by density functional theory (DFT) using the M05-2X method with 6-311++G** basis set and solvation model based on density (SMD). The results revealed that H-abstraction on the phenol group is the most favorable pathway for OH. The theoretical k value corrected by the Collins-Kimball approach was determined to be 1.03 × 10(10) M(-1) s(-1), which is in reasonable agreement with the experimental observation. These results are of fundamental and practical importance in understanding the chemical interactions between OH and BPA, and aid further AOPs design in treating EDCs during wastewater treatment processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Biodiversity and Complexity Influence Seagrass Functioning: A Comparative-Experimental Approach Across the Northern Hemisphere (United States)

    Reynolds, P. L.


    Coastal ecosystems are mediated by interactions between resource supply, consumer pressure, and community composition, with the balance shifting along environmental gradients. Comparative-experimental approaches, including observational and experimental networks, are a promising way forward to organizing this complexity into predictive models and to quantify the role of biodiversity on ocean processes. Through the Zostera Experimental Network we utilize this approach to study the community ecology of eelgrass (Zostera marina), the most widespread marine plant and foundation of important but threatened coastal ecosystems throughout the northern hemisphere. In 2014, parallel field surveys and experiments were conducted at 50 field sites to measure correlations between mesograzer species diversity, eelgrass genetic diversity, predation pressure, and seagrass dynamics. Biodiversity was positively correlated with plant and grazer biomass across sites. Predation pressure in these systems decreased with grazer biomass and latitude. In subsequent experiments in 2015, habitat complexity influenced the grazer community. These results suggest that the impacts of biodiversity loss on ecosystems will be of comparable magnitude to those of other global change factors and should be accounted for in relevant monitoring and restoration activities.

  2. Experimental and Analytical Study Approach of Artificial Basilar Membrane Prototype (ABMP

    Directory of Open Access Journals (Sweden)

    Harto Tanujaya


    Full Text Available In this research, we have developed, fabricated, tested, and analyzed an artificial basilar membrane prototype (ABMP, which works using sinusoidal waves of various frequencies. The design of the prototype has a trapezoidal shape with a length of 30 mm and a width of 2 to 4 mm. The research was carried out experimentally and analytically. Experimentally, the ABMP’s vibration was measured using a laser Doppler vibrometer (LDV and a function generator to generate various frequencies. The analytical approach is discussed based on the Wentzel Kramer Brillouin method (WKB. The results show that resonance frequencies can be reached within the range of human hearing, between 20 Hz to 20 kHz.

  3. From Experimental Approaches to Computational Techniques: A Review on the Prediction of Protein-Protein Interactions

    Directory of Open Access Journals (Sweden)

    Fiona Browne


    Full Text Available A crucial step towards understanding the properties of cellular systems in organisms is to map their network of protein-protein interactions (PPIs on a proteomic-wide scale completely and as accurately as possible. Uncovering the diverse function of proteins and their interactions within the cell may improve our understanding of disease and provide a basis for the development of novel therapeutic approaches. The development of large-scale high-throughput experiments has resulted in the production of a large volume of data which has aided in the uncovering of PPIs. However, these data are often erroneous and limited in interactome coverage. Therefore, additional experimental and computational methods are required to accelerate the discovery of PPIs. This paper provides a review on the prediction of PPIs addressing key prediction principles and highlighting the common experimental and computational techniques currently employed to infer PPI networks along with relevant studies in the area.

  4. Paul Baillon presents the book "Differential manifolds: a basic approach for experimental physicists" | 25 March

    CERN Multimedia

    CERN Library


    Tuesday 25 March 2014 at 4 p.m. in the Library, bldg. 52-1-052 "Differential manifolds: a basic approach for experimental physicists" by Paul Baillon,  World Scientific, 2013, ISBN 978-981-4449-56-4. Differential manifold is the framework of particle physics and astrophysics nowadays. It is important for all research physicists to be accustomed to it, and even experimental physicists should be able to manipulate equations and expressions in this framework. This book gives a comprehensive description of the basics of differential manifold with a full proof of elements. A large part of the book is devoted to the basic mathematical concepts, which are all necessary for the development of the differential manifold. This book is self-consistent; it starts from first principles. The mathematical framework is the set theory with its axioms and its formal logic. No special knowledge is needed. Coffee will be served from 3.30 p.m.

  5. Development of an experimental approach to study coupled soil-plant-atmosphere processes using plant analogs (United States)

    Trautz, Andrew C.; Illangasekare, Tissa H.; Rodriguez-Iturbe, Ignacio; Heck, Katharina; Helmig, Rainer


    The atmosphere, soils, and vegetation near the land-atmosphere interface are in a state of continuous dynamic interaction via a myriad of complex interrelated feedback processes which collectively, remain poorly understood. Studying the fundamental nature and dynamics of such processes in atmospheric, ecological, and/or hydrological contexts in the field setting presents many challenges; current experimental approaches are an important factor given a general lack of control and high measurement uncertainty. In an effort to address these issues and reduce overall complexity, new experimental design considerations (two-dimensional intermediate-scale coupled wind tunnel-synthetic aquifer testing using synthetic plants) for studying soil-plant-atmosphere continuum soil moisture dynamics are introduced and tested in this study. Validation of these experimental considerations, particularly the adoption of synthetic plants, is required prior to their application in future research. A comparison of three experiments with bare soil surfaces or transplanted with a Stargazer lily/limestone block was used to evaluate the feasibility of the proposed approaches. Results demonstrate that coupled wind tunnel-porous media experimentation, used to simulate field conditions, reduces complexity, and enhances control while allowing fine spatial-temporal resolution measurements to be made using state-of-the-art technologies. Synthetic plants further help reduce system complexity (e.g., airflow) while preserving the basic hydrodynamic functions of plants (e.g., water uptake and transpiration). The trends and distributions of key measured atmospheric and subsurface spatial and temporal variables (e.g., soil moisture, relative humidity, temperature, air velocity) were comparable, showing that synthetic plants can be used as simple, idealized, nonbiological analogs for living vegetation in fundamental hydrodynamic studies.

  6. Methodological framework for ex-ante assessment of active policies on the labor market - experimental approach

    Directory of Open Access Journals (Sweden)

    Daniela PASNICU


    The article presents a methodological framework for ex-ante assessment of active measures for the employment growth in the context of rural areas, on the bases of efficiency, effectiveness and coherence criteria. Ex-ante social impact assessment of an active policy can have beneficial effects on employment under quantitative and qualitative aspects. The novelty of the article consist in the specific, experimental approach of the development and of ex-ante evaluation of active labor market policies, in the context of rural areas.

  7. Experimental approaches to study plant cell walls during plant-microbe interactions. (United States)

    Xia, Ye; Petti, Carloalberto; Williams, Mark A; DeBolt, Seth


    Plant cell walls provide physical strength, regulate the passage of bio-molecules, and act as the first barrier of defense against biotic and abiotic stress. In addition to providing structural integrity, plant cell walls serve an important function in connecting cells to their extracellular environment by sensing and transducing signals to activate cellular responses, such as those that occur during pathogen infection. This mini review will summarize current experimental approaches used to study cell wall functions during plant-pathogen interactions. Focus will be paid to cell imaging, spectroscopic analyses, and metabolic profiling techniques.

  8. ANN Approach for State Estimation of Hybrid Systems and Its Experimental Validation

    Directory of Open Access Journals (Sweden)

    Shijoh Vellayikot


    Full Text Available A novel artificial neural network based state estimator has been proposed to ensure the robustness in the state estimation of autonomous switching hybrid systems under various uncertainties. Taking the autonomous switching three-tank system as benchmark hybrid model working under various additive and multiplicative uncertainties such as process noise, measurement error, process–model parameter variation, initial state mismatch, and hand valve faults, real-time performance evaluation by the comparison of it with other state estimators such as extended Kalman filter and unscented Kalman Filter was carried out. The experimental results reported with the proposed approach show considerable improvement in the robustness in performance under the considered uncertainties.

  9. Advances in the indirect, descriptive, and experimental approaches to the functional analysis of problem behavior. (United States)

    Wightman, Jade; Julio, Flávia; Virués-Ortega, Javier


    Experimental functional analysis is an assessment methodology to identify the environmental factors that maintain problem behavior in individuals with developmental disabilities and in other populations. Functional analysis provides the basis for the development of reinforcement-based approaches to treatment. This article reviews the procedures, validity, and clinical implementation of the methodological variations of functional analysis and function-based interventions. We present six variations of functional analysis methodology in addition to the typical functional analysis: brief functional analysis, single-function tests, latency-based functional analysis, functional analysis of precursors, and trial-based functional analysis. We also present the three general categories of function-based interventions: extinction, antecedent manipulation, and differential reinforcement. Functional analysis methodology is a valid and efficient approach to the assessment of problem behavior and the selection of treatment strategies.

  10. A Statistical Approach for Selecting Buildings for Experimental Measurement of HVAC Needs

    Directory of Open Access Journals (Sweden)

    Malinowski Paweł


    Full Text Available This article presents a statistical methodology for selecting representative buildings for experimentally evaluating the performance of HVAC systems, especially in terms of energy consumption. The proposed approach is based on the k-means method. The algorithm for this method is conceptually simple, allowing it to be easily implemented. The method can be applied to large quantities of data with unknown distributions. The method was tested using numerical experiments to determine the hourly, daily, and yearly heat values and the domestic hot water demands of residential buildings in Poland. Due to its simplicity, the proposed approach is very promising for use in engineering applications and is applicable to testing the performance of many HVAC systems.

  11. A Statistical Approach for Selecting Buildings for Experimental Measurement of HVAC Needs (United States)

    Malinowski, Paweł; Ziembicki, Piotr


    This article presents a statistical methodology for selecting representative buildings for experimentally evaluating the performance of HVAC systems, especially in terms of energy consumption. The proposed approach is based on the k-means method. The algorithm for this method is conceptually simple, allowing it to be easily implemented. The method can be applied to large quantities of data with unknown distributions. The method was tested using numerical experiments to determine the hourly, daily, and yearly heat values and the domestic hot water demands of residential buildings in Poland. Due to its simplicity, the proposed approach is very promising for use in engineering applications and is applicable to testing the performance of many HVAC systems.

  12. Experimental design approach for the solid-phase extraction of residual aluminium coagulants in treated waters. (United States)

    Vanloot, P; Boudenne, J-L; Vassalo, Laurent; Sergent, M; Coulomb, B


    Solid-phase extraction (SPE) of trace elements before their analysis has become a conventional pretreatment step of analytes because of their frequent low concentrations in numerous samples. Additionally, interfering compounds often accompagny analytes of interest, thus requiring a clean-up step. The preconcentration step and/or matrix removal can be efficiently improved by chemometric approaches allowing obtention of reliable results. Single variable approach is often used but is time and cost consuming, and may be the source of mistakes; multivariable approach allows to overcome these problems and increases the probability of global optimum finding. In order to obtain a set of experimental conditions for the selective extraction of Al(III) in water samples, onto a modified organic support (salicylic acid grafted on XAD-4), a multicriteria approach (response surface methodology) has been applied. The extraction method was optimized by the aid of a factorial design and a uniform shell Doehlert design for six variables: sample percolation flow rate, trace metal amount, sample volume, concentration and volume of HCl used for elution of aluminium. Results demonstrate the synergic effects of four factors and allow us to define working ranges for each parameter tested. The designed SPE procedure was then sucessfully applied to synthetic and real samples, issued from a potable water treatment unit.

  13. Elements of a flexible approach for conceptual hydrological modeling: 2. Application and experimental insights (United States)

    Kavetski, Dmitri; Fenicia, Fabrizio


    In this article's companion paper, flexible approaches for conceptual hydrological modeling at the catchment scale were motivated, and the SUPERFLEX framework, based on generic model components, was introduced. In this article, the SUPERFLEX framework and the "fixed structure" GR4H model (an hourly version of the popular GR4J model) are applied to four hydrologically distinct experimental catchments in Europe and New Zealand. The estimated models are scrutinized using several diagnostic measures, ranging from statistical metrics, such as the statistical reliability and precision of the predictive distribution of streamflow, to more process-oriented diagnostics based on flow-duration curves and the correspondence between model states and groundwater piezometers. Model performance was clearly catchment specific, with a single fixed structure unable to accommodate intercatchment differences in hydrological behavior, including seasonality and thresholds. This highlights an important limitation of any "fixed" model structure. In the experimental catchments, the ability of competing model hypotheses to reproduce hydrological signatures of interest could be interpreted on the basis of independent fieldwork insights. The potential of flexible frameworks such as SUPERFLEX is then examined with respect to systematic and stringent hypothesis-testing in hydrological modeling, for characterizing catchment diversity, and, more generally, for aiding progress toward a more unified formulation of hydrological theory at the catchment scale. When interpreted in physical process-oriented terms, the flexible approach can also serve as a language for dialogue between modeler and experimentalist, facilitating the understanding, representation, and interpretation of catchment behavior.

  14. Novel Experimental-Modeling Approach for Characterizing Perfluorinated Surfactants in Soils. (United States)

    Courtier-Murias, Denis; Michel, Eric; Rodts, Stéphane; Lafolie, François


    Soil contamination is still poorly understood and modeled in part because of the difficulties of looking inside the "black box" constituted by soils. Here, we investigated the application of a recently developed 1 H NMR technique to 19 F NMR relaxometry experiments and utilized the results as inputs for an existing model. This novel approach yields 19 F T 2 NMR relaxation values of any fluorinated contaminant, which are among the most dangerous contaminants, allowing us to noninvasively and directly monitor their fate in soils. Using this protocol, we quantified the amount of a fluorinated xenobiotic (heptafluorobutyric acid, HFBA) in three different environments in soil aggregate packings and monitored contaminant exchange dynamics between these compartments. A model computing HFBA partition dynamics between different soil compartments showed that these three environments corresponded to HFBA in solution (i) between and (ii) inside the soil aggregates and (iii) to HFBA adsorbed to (or strongly interacting with) the soil constituents. In addition to providing a straightforward way of determining the sorption kinetics of any fluorinated contaminant, this work also highlights the strengths of a combined experimental-modeling approach to unambiguously understand experimental data and more generally to study contaminant fate in soils.

  15. Experimental evaluation of anti-sound approach in damping self-sustained thermoacoustics oscillations (United States)

    Li, Xinyan; Zhao, Dan; Li, Junwei; Xu, Yousheng


    Self-sustained thermoacoustics oscillations most often arise due to the coupling between unsteady heat release and acoustic waves. The large-amplitude oscillations are wanted in thermoacoustic engine systems. However, they are undesirable in many other systems such as aero-engine afterburners, rocket motors, ramjets, and gas turbines, since the oscillations may become so intense that they cause structural damage and costly mission failure. In this work, we experimentally investigate the "anti-sound" approach in damping Rijke-type thermoacoustic oscillations by actuating a monopole-like sound source. For this, four different least-mean-square (LMS) algorithms are used to determine the "anti-sound" signal to drive the actuator. Comparison is then made. It is found that the LMS-based "anti-sound" approach is able to minimize the thermoacoustic oscillations, even when the operating conditions are slightly changed. Sound pressure level is reduced by 45 dB. Finally, a numerical model is developed to gain insights on the interaction between the monopole sound source and the system. Unsteady heat release from the flame is assumed to be caused by its surface variations resulting from the oncoming acoustic fluctuations. By linearizing the flame model and recasting it into the classical time-lag N -τ formulation, the thermoacoustic system transfer function is calculated. Compared with the experimental measurement by injecting a broad-band white noise, good agreement is obtained.

  16. [Methodological approaches to the experimental study of the impact of environmental pollution on the human body]. (United States)

    Sosedova, L M


    In the materials there are presented features of methodological approaches in the performing of experimental studies concerning of the investigation of the impacts of environmental factors on the human body. There were shown the results of our experiments performed at the Institute, in the modeling of biological effects of antimicrobial nanobiocomposites with nanosilver particles, toxic encephalopathy, in the study of the combined effect of the factors of biological and chemical nature. There was proved the importance of intracellular of proteomics in the assessment of the effects of the action of nanoparticles and nanomaterials on the body. There were revealed key parts of progredient course of mercury poisoning in the long-term. The special section is presented by the study of long-term effects of anthropogenic environmental factors on subsequent generations. There are presented results witnessing to a deterioration of the functional state of the central nervous system in rats in the first and second generations, whose parents were exposed to neurotoxicants. There was proved the aggravating role of prenatal hypoxia in the development of toxicity in rats in sexually mature age. Experimental biomodeling is aimed at sighting of pathogenetically substantiated treatment and preventive measures: initially, in experimental conditions, and in the future in the rehabilitation of sick or injured patients.

  17. Coupling glucose fermentation and homoacetogenesis for elevated acetate production: Experimental and mathematical approaches. (United States)

    Ni, Bing-Jie; Liu, He; Nie, Yan-Qiu; Zeng, Raymond J; Du, Guo-Cheng; Chen, Jian; Yu, Han-Qing


    Homoacetogenesis is an important potential hydrogen sink in acetogenesis, in which hydrogen is used to reduce carbon dioxide to acetate. So far the acetate production from homoacetogenesis, especially its kinetics, has not been given sufficient attention. In this work, enhanced production of acetate from anaerobic conversion of glucose through coupling glucose fermentation and homoacetogenesis is investigated with both experimental and mathematical approaches. Experiments are conducted to explore elevated acetate production in a coupled anaerobic system. Acetate production could be achieved by homoacetogenesis with a relative high acetate yield under mixed fermentation conditions. With the experimental observations, a kinetic model is formulated to describe such a homoacetogenic process. The maximum homoacetogenic rate (k(m,homo)) is estimated to be 28.5 ± 1.7 kg COD kg⁻¹ COD day⁻¹ with an uptake affinity constant of 3.7 × 10⁻⁵± 3.1 × 10⁻⁶kg COD m⁻³. The improved calculation of homoacetogenic kinetics by our approach could correct the underestimation of homoacetogenesis in anaerobic fermentation processes, as it often occurs in these systems supported by literature analysis. The model predictions match the experimental results in different cases well and provide insights into the dynamics of anaerobic glucose conversion and acetate production. Furthermore, acetate production via homoacetogenesis increases by about 40% through utilizing the fed-batch coupling system, attributed to a balance between the hydrogen production in the acetogenesis phase and the hydrogen consumption in the homoacetogenesis phase. This work provides an effective way for increased anaerobic acetate production, and gives us a better understanding about the homoacetogenic kinetics in the anaerobic fermentation process. © 2010 Wiley Periodicals, Inc.

  18. Frequency-Dependent Streaming Potential of Porous Media—Part 1: Experimental Approaches and Apparatus Design

    Directory of Open Access Journals (Sweden)

    P. W. J. Glover


    Full Text Available Electrokinetic phenomena link fluid flow and electrical flow in porous and fractured media such that a hydraulic flow will generate an electrical current and vice versa. Such a link is likely to be extremely useful, especially in the development of the electroseismic method. However, surprisingly few experimental measurements have been carried out, particularly as a function of frequency because of their difficulty. Here we have considered six different approaches to make laboratory determinations of the frequency-dependent streaming potential coefficient. In each case, we have analyzed the mechanical, electrical, and other technical difficulties involved in each method. We conclude that the electromagnetic drive is currently the only approach that is practicable, while the piezoelectric drive may be useful for low permeability samples and at specified high frequencies. We have used the electro-magnetic drive approach to design, build, and test an apparatus for measuring the streaming potential coefficient of unconsolidated and disaggregated samples such as sands, gravels, and soils with a diameter of 25.4 mm and lengths between 50 mm and 300 mm.

  19. Three experimental approaches to measure the social context dependence of prejudice communication and discriminatory behavior. (United States)

    Beyer, Heiko; Liebe, Ulf


    Empirical research on discrimination is faced with crucial problems stemming from the specific character of its object of study. In democratic societies the communication of prejudices and other forms of discriminatory behavior is considered socially undesirable and depends on situational factors such as whether a situation is considered private or whether a discriminatory consensus can be assumed. Regular surveys thus can only offer a blurred picture of the phenomenon. But also survey experiments intended to decrease the social desirability bias (SDB) so far failed in systematically implementing situational variables. This paper introduces three experimental approaches to improve the study of discrimination and other topics of social (un-)desirability. First, we argue in favor of cognitive context framing in surveys in order to operationalize the salience of situational norms. Second, factorial surveys offer a way to take situational contexts and substitute behavior into account. And third, choice experiments - a rather new method in sociology - offer a more valid method of measuring behavioral characteristics compared to simple items in surveys. All three approaches - which may be combined - are easy to implement in large-scale surveys. Results of empirical studies demonstrate the fruitfulness of each of these approaches. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. From the ideal to the real induction machine: Modelling approach and experimental validation (United States)

    Bottauscio, O.; Chiampi, M.; Concari, C.; Tassoni, C.; Zucca, M.

    The aim of this paper is to discuss the ability of a numerical code in reproducing a real machine behavior, with particular reference to the cage currents of a four-poles 50 Hz induction motor. The used 2D Finite Element method (FEM) is based on voltage driven field formulation, handling the nonlinearity by the fixed point technique and the rotor movement by the sliding mesh approach. The numerical outcomes are validated by experiments performed on a dedicated laboratory setup, able to provide the instantaneous cage currents. Then, a spectral algorithm has been applied to the experimental and computed variables and the results have been interpreted in terms of magneto-motive forces. This approach allows us to determine possible machine eccentricities or other asymmetries not introduced in the simulations. Discussing the computed and measured spectra and excluding in the last ones the lines corresponding to non-idealities, an evaluation on how the modelling approach reproduces accurately the real machine is possible. The validated model will be able to reproduce the machine behavior of usual induction machines whose rotor currents are not measurable.

  1. Direct modeling of coda wave interferometry: comparison of numerical and experimental approaches (United States)

    Azzola, Jérôme; Masson, Frédéric; Schmittbuhl, Jean


    The sensitivity of coda waves to small changes of the propagation medium is the principle of the coda waves interferometry, a technique which has been found to have a large range of applications over the past years. It exploits the evolution of strongly scattered waves in a limited region of space, to estimate slight changes like the wave velocity of the medium but also the location of scatterer positions or the stress field. Because of the sensitivity of the method, it is of a great value for the monitoring of geothermal EGS reservoir in order to detect fine changes. The aim of this work is thus to monitor the impact of different scatterer distributions and of the loading condition evolution using coda wave interferometry in the laboratory and numerically by modelling the scatter wavefield. In the laboratory, we analyze the scattering of an acoustic wave through a perforated loaded plate of DURAL. Indeed, the localized damages introduced behave as a scatter source. Coda wave interferometry is performed computing correlations of waveforms under different loading conditions, for different scatter distributions. Numerically, we used SPECFEM2D (a 2D spectral element code, (Komatitsch and Vilotte (1998)) to perform 2D simulations of acoustic and elastic seismic wave propagation and enables a direct comparison with laboratory and field results. An unstructured mesh is thus used to simulate the propagation of a wavelet in a loaded plate, before and after introduction of localized damages. The linear elastic deformation of the plate is simulated using Code Aster. The coda wave interferometry is performed similarly to experimental measurements. The accuracy of the comparison of the numerically and laboratory obtained results is strongly depending on the capacity to adapt the laboratory and numerical simulation conditions. In laboratory, the capacity to illuminate the medium in a similar way to that used in the numerical simulation deeply conditions among others the

  2. Experimental Validation of a Differential Variational Inequality-Based Approach for Handling Friction and Contact in Vehicle (United States)


    terrain modeled using the discrete element method (DEM). Experimental Validation of a Differential Variational Inequality -Based Approach for Handling...COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE Experimental Validation of a Differential Variational Inequality -Based Approach for...sinkage, and single wheel tests. 1.1. Modeling Frictional Contact Via Differential Variational Inequalities Consider a three dimensional (3D) system of

  3. Improving Wind Turbine Drivetrain Reliability Using a Combined Experimental, Computational, and Analytical Approach

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Y.; van Dam, J.; Bergua, R.; Jove, J.; Campbell, J.


    Nontorque loads induced by the wind turbine rotor overhang weight and aerodynamic forces can greatly affect drivetrain loads and responses. If not addressed properly, these loads can result in a decrease in gearbox component life. This work uses analytical modeling, computational modeling, and experimental data to evaluate a unique drivetrain design that minimizes the effects of nontorque loads on gearbox reliability: the Pure Torque(R) drivetrain developed by Alstom. The drivetrain has a hub-support configuration that transmits nontorque loads directly into the tower rather than through the gearbox as in other design approaches. An analytical model of Alstom's Pure Torque drivetrain provides insight into the relationships among turbine component weights, aerodynamic forces, and the resulting drivetrain loads. Main shaft bending loads are orders of magnitude lower than the rated torque and are hardly affected by wind conditions and turbine operations.

  4. Approaches to enhance the teaching quality of experimental biochemistry for MBBS students in TSMU, China. (United States)

    Yu, Lijuan; Yi, Shuying; Zhai, Jing; Wang, Zhaojin


    With the internationalization of medical education in China, the importance of international students' education in medical schools is also increasing. Except foreign students majoring in Chinese language, English Bachelor of Medicine, Bachelor of Surgery (MBSS) students are the largest group of international students. Based on problems in the teaching process for experimental biochemistry, we designed teaching models adapted to the background of international students and strengthened teachers' teaching ability at Taishan Medical University. Several approaches were used in combination to promote teaching effects and increase the benefit of teaching to teachers. The primary data showed an increased passion for basic medical biochemistry and an improved theoretical background for MBSS students, which will be helpful for their later clinical medicine studies. © 2017 by The International Union of Biochemistry and Molecular Biology, 45(4):360-364, 2017. © 2017 The International Union of Biochemistry and Molecular Biology.

  5. An interdisciplinary and experimental approach applied to an analysis of the communication of influence

    Directory of Open Access Journals (Sweden)

    Brigitte JUANALS


    Full Text Available This paper describes the added value of an interdisciplinary and experimental approach applied to an analysis of the inter-organizational communication of influence. The field analyzed is the international industrial standardization of societal security. A communicational problem has been investigated with an experimental method based on natural language processing and knowledge management tools. The purpose of the methodological framework is to clarify the way international standards are designed and the policies that are supported by these standards. Furthermore, strategies of influence of public and private stakeholders involved in the NGOs which produce these texts have also been studied. The means of inter-organizational communication between organizations (companies or governmental authorities and NGOs can be compared to the lobbying developed in the context of the construction of Europe and globalization. Understanding the prescriptive process has become a crucial issue for States, organizations and citizens. This research contributes to the critical assessment of the new industrial policies currently being developed from the point of view of their characteristics and the way they have been designed.

  6. Experimental instruction in photonics for high school students: approaches to managing problems faced (United States)

    Choong, Zhengyang


    Student research projects are increasingly common at the K-12 level. However, students often face difficulties in the course of their school research projects such as setting realistic timelines and expectations, handling problems stemming from a lack of self-confidence, as well as being sufficiently disciplined for sustained communication and experimentation. In this work, we explore manifestations of these problems in the context of a photonics project, characterising the spectrum of the breakdown flash from Silicon Avalanche Photodiodes. We report on the process of planning and building the setup, data collection, analysis and troubleshooting, as well as the technical and human problems at each step. Approaches that were found to be helpful in managing the aforementioned problems are discussed, including an attention to detail during experimental work, as well as communicating in a forthcoming manner. Œe former allowed for clearer planning and the setting of quantifiable proximal goals; the latter helped in motivating discipline, and also helped in the understanding of research as an iterative learning process without a clear definition of success or failure.

  7. Investigation of sonar transponders for offshore wind farms: modeling approach, experimental setup, and results. (United States)

    Fricke, Moritz B; Rolfes, Raimund


    The installation of offshore wind farms in the German Exclusive Economic Zone requires the deployment of sonar transponders to prevent collisions with submarines. The general requirements for these systems have been previously worked out by the Research Department for Underwater Acoustics and Marine Geophysics of the Bundeswehr. In this article, the major results of the research project "Investigation of Sonar Transponders for Offshore Wind Farms" are presented. For theoretical investigations a hybrid approach was implemented using the boundary element method to calculate the source directivity and a three-dimensional ray-tracing algorithm to estimate the transmission loss. The angle-dependence of the sound field as well as the weather-dependence of the transmission loss are compared to experimental results gathered at the offshore wind farm alpha ventus, located 45 km north of the island Borkum. While theoretical and experimental results are in general agreement, the implemented model slightly underestimates scattering at the rough sea surface. It is found that the source level of 200 dB re 1 μPa at 1 m is adequate to satisfy the detectability of the warning sequence at distances up to 2 NM (≈3.7 km) within a horizontal sector of ±60° if realistic assumptions about signal-processing and noise are made. An arrangement to enlarge the angular coverage is discussed.

  8. Experimental study on distributed optical fiber-based approach monitoring saturation line in levee engineering (United States)

    Su, Huaizhi; Li, Hao; Kang, Yeyuan; Wen, Zhiping


    Seepage is one of key factors which affect the levee engineering safety. The seepage danger without timely detection and rapid response may likely lead to severe accidents such as seepage failure, slope instability, and even levee break. More than 90 percent of levee break events are caused by the seepage. It is very important for seepage behavior identification to determine accurately saturation line in levee engineering. Furthermore, the location of saturation line has a major impact on slope stability in levee engineering. Considering the structure characteristics and service condition of levee engineering, the distributed optical fiber sensing technology is introduced to implement the real-time observation of saturation line in levee engineering. The distributed optical fiber temperature sensor system (DTS)-based monitoring principle of saturation line in levee engineering is investigated. An experimental platform, which consists of DTS, heating system, water-supply system, auxiliary analysis system and levee model, is designed and constructed. The monitoring experiment of saturation line in levee model is implemented on this platform. According to the experimental results, the numerical relationship between moisture content and thermal conductivity in porous medium is identified. A line heat source-based distributed optical fiber method obtaining the thermal conductivity in porous medium is developed. A DTS-based approach is proposed to monitor the saturation line in levee engineering. The embedment pattern of optical fiber for monitoring saturation line is presented.

  9. An experimental approach to identify dynamical models of transcriptional regulation in living cells (United States)

    Fiore, G.; Menolascina, F.; di Bernardo, M.; di Bernardo, D.


    We describe an innovative experimental approach, and a proof of principle investigation, for the application of System Identification techniques to derive quantitative dynamical models of transcriptional regulation in living cells. Specifically, we constructed an experimental platform for System Identification based on a microfluidic device, a time-lapse microscope, and a set of automated syringes all controlled by a computer. The platform allows delivering a time-varying concentration of any molecule of interest to the cells trapped in the microfluidics device (input) and real-time monitoring of a fluorescent reporter protein (output) at a high sampling rate. We tested this platform on the GAL1 promoter in the yeast Saccharomyces cerevisiae driving expression of a green fluorescent protein (Gfp) fused to the GAL1 gene. We demonstrated that the System Identification platform enables accurate measurements of the input (sugars concentrations in the medium) and output (Gfp fluorescence intensity) signals, thus making it possible to apply System Identification techniques to obtain a quantitative dynamical model of the promoter. We explored and compared linear and nonlinear model structures in order to select the most appropriate to derive a quantitative model of the promoter dynamics. Our platform can be used to quickly obtain quantitative models of eukaryotic promoters, currently a complex and time-consuming process.

  10. Quantifying and exploiting entanglement (United States)

    Ali Khan, Irfan

    The aim of this work is to explore the characterization of various entangled parameters of the two-photon state that is created in the process of spontaneous parametric down-conversion, as well as to investigate the potential application of these two-photon states to quantum communication and quantum information processing. The parameters fall into two natural divisions, the discrete-variable and continuous-variable regimes. Polarization-correlated photon pairs are used to explore the discrete-variable regime. Using these polarization-correlated photon pairs we investigate phase-covariant quantum cloning, sum-variance entanglement measures, and unambiguous state-discrimination. Phase-covariant quantum cloning is experimentally demonstrated to provide higher cloning fidelity than a universal quantum cloner. The simplicity of the practical implementation of this cloning method makes this cloner a useful addition to the quantum information and communication toolbox. Next, it is experimentally demonstrated that three, concatenating, sum-variance entanglement measures possess higher sensitivities than the popular Bell entanglement measure, while each requires fewer measurements than a Bell measurement to obtain. Finally, it is demonstrated that unambiguous state-discrimination of nonorthogonal, bipartite entangled-states involves an analogous physical mechanism to that of entanglement distillation of bipartite entangled states. This physical mechanism is the basis of a two-qudit, three-party secret sharing protocol. In the continuous variable regime, two-photon position-momentum entanglement and two-photon time-energy entanglement is explored. Entanglement between discrete regions of space (pixels) is demonstrated using transverse momentum and position entanglement. Each photon is mapped onto as many as six pixels, where each pixel represents one level of a qudit state. Next, the number of information eigenmodes K of time-energy entanglement is investigated. Explicit

  11. Schistosoma mansoni cercariae exploit an elastohydrodynamic coupling to swim efficiently

    CERN Document Server

    Krishnamurthy, Deepak; Bhargava, Arjun; Prakash, Manu


    The motility of many parasites is critical for the infection process of their host, as exemplified by the transmission cycle of the blood fluke Schistosoma mansoni. In their human infectious stage, immature, submillimetre-scale forms of the parasite known as cercariae swim in freshwater and infect humans by penetrating through the skin. This infection causes Schistosomiasis, a parasitic disease that is comparable to malaria in its global socio-economic impact. Given that cercariae do not feed and hence have a finite lifetime of around 12 hours, efficient motility is crucial for the parasite's survival and transmission of Schistosomiasis. However, a first-principles understanding of how cercariae swim is lacking. Via a combined experimental, theoretical and robotics based approach, we demonstrate that cercariae propel themselves against gravity by exploiting a unique elastohydrodynamic coupling. We show that cercariae beat their tail in a periodic fashion while maintaining a fixed flexibility near their poster...

  12. Experimental Validation of Various Temperature Modells for Semi-Physical Tyre Model Approaches (United States)

    Hackl, Andreas; Scherndl, Christoph; Hirschberg, Wolfgang; Lex, Cornelia


    With increasing level of complexity and automation in the area of automotive engineering, the simulation of safety relevant Advanced Driver Assistance Systems (ADAS) leads to increasing accuracy demands in the description of tyre contact forces. In recent years, with improvement in tyre simulation, the needs for coping with tyre temperatures and the resulting changes in tyre characteristics are rising significantly. Therefore, experimental validation of three different temperature model approaches is carried out, discussed and compared in the scope of this article. To investigate or rather evaluate the range of application of the presented approaches in combination with respect of further implementation in semi-physical tyre models, the main focus lies on the a physical parameterisation. Aside from good modelling accuracy, focus is held on computational time and complexity of the parameterisation process. To evaluate this process and discuss the results, measurements from a Hoosier racing tyre 6.0 / 18.0 10 LCO C2000 from an industrial flat test bench are used. Finally the simulation results are compared with the measurement data.

  13. Wnt-signalling pathways and microRNAs network in carcinogenesis: experimental and bioinformatics approaches. (United States)

    Onyido, Emenike K; Sweeney, Eloise; Nateri, Abdolrahman Shams


    Over the past few years, microRNAs (miRNAs) have not only emerged as integral regulators of gene expression at the post-transcriptional level but also respond to signalling molecules to affect cell function(s). miRNAs crosstalk with a variety of the key cellular signalling networks such as Wnt, transforming growth factor-β and Notch, control stem cell activity in maintaining tissue homeostasis, while if dysregulated contributes to the initiation and progression of cancer. Herein, we overview the molecular mechanism(s) underlying the crosstalk between Wnt-signalling components (canonical and non-canonical) and miRNAs, as well as changes in the miRNA/Wnt-signalling components observed in the different forms of cancer. Furthermore, the fundamental understanding of miRNA-mediated regulation of Wnt-signalling pathway and vice versa has been significantly improved by high-throughput genomics and bioinformatics technologies. Whilst, these approaches have identified a number of specific miRNA(s) that function as oncogenes or tumour suppressors, additional analyses will be necessary to fully unravel the links among conserved cellular signalling pathways and miRNAs and their potential associated components in cancer, thereby creating therapeutic avenues against tumours. Hence, we also discuss the current challenges associated with Wnt-signalling/miRNAs complex and the analysis using the biomedical experimental and bioinformatics approaches.

  14. Evaluating in Vitro Culture Medium of Gut Microbiome with Orthogonal Experimental Design and a Metaproteomics Approach. (United States)

    Li, Leyuan; Zhang, Xu; Ning, Zhibin; Mayne, Janice; Moore, Jasmine I; Butcher, James; Chiang, Cheng-Kang; Mack, David; Stintzi, Alain; Figeys, Daniel


    In vitro culture based approaches are time- and cost-effective solutions for rapidly evaluating the effects of drugs or natural compounds against microbiomes. The nutritional composition of the culture medium is an important determinant for effectively maintaining the gut microbiome in vitro. This study combines orthogonal experimental design and a metaproteomics approach to obtaining functional insights into the effects of different medium components on the microbiome. Our results show that the metaproteomic profile respond differently to medium components, including inorganic salts, bile salts, mucin, and short-chain fatty acids. Multifactor analysis of variance further revealed significant main and interaction effects of inorganic salts, bile salts, and mucin on the different functional groups of gut microbial proteins. While a broad regulating effect was observed on basic metabolic pathways, different medium components also showed significant modulations on cell wall, membrane, and envelope biogenesis and cell motility related functions. In particular, flagellar assembly related proteins were significantly responsive to the presence of mucin. This study provides information on the functional influences of medium components on the in vitro growth of microbiome communities and gives insight on the key components that must be considered when selecting and optimizing media for culturing ex vivo microbiotas.

  15. An experimental MOSFET approach to characterize (192)Ir HDR source anisotropy. (United States)

    Toye, W C; Das, K R; Todd, S P; Kenny, M B; Franich, R D; Johnston, P N


    The dose anisotropy around a (192)Ir HDR source in a water phantom has been measured using MOSFETs as relative dosimeters. In addition, modeling using the EGSnrc code has been performed to provide a complete dose distribution consistent with the MOSFET measurements. Doses around the Nucletron 'classic' (192)Ir HDR source were measured for a range of radial distances from 5 to 30 mm within a 40 x 30 x 30 cm(3) water phantom, using a TN-RD-50 MOSFET dosimetry system with an active area of 0.2 mm by 0.2 mm. For each successive measurement a linear stepper capable of movement in intervals of 0.0125 mm re-positioned the MOSFET at the required radial distance, while a rotational stepper enabled angular displacement of the source at intervals of 0.9 degrees . The source-dosimeter arrangement within the water phantom was modeled using the standardized cylindrical geometry of the DOSRZnrc user code. In general, the measured relative anisotropy at each radial distance from 5 mm to 30 mm is in good agreement with the EGSnrc simulations, benchmark Monte Carlo simulation and TLD measurements where they exist. The experimental approach employing a MOSFET detection system of small size, high spatial resolution and fast read out capability allowed a practical approach to the determination of dose anisotropy around a HDR source.

  16. A theoretical and experimental approach for correlating nanoparticle structure and electrocatalytic activity. (United States)

    Anderson, Rachel M; Yancey, David F; Zhang, Liang; Chill, Samuel T; Henkelman, Graeme; Crooks, Richard M


    The objective of the research described in this Account is the development of high-throughput computational-based screening methods for discovery of catalyst candidates and subsequent experimental validation using appropriate catalytic nanoparticles. Dendrimer-encapsulated nanoparticles (DENs), which are well-defined 1-2 nm diameter metal nanoparticles, fulfill the role of model electrocatalysts. Effective comparison of theory and experiment requires that the theoretical and experimental models map onto one another perfectly. We use novel synthetic methods, advanced characterization techniques, and density functional theory (DFT) calculations to approach this ideal. For example, well-defined core@shell DENs can be synthesized by electrochemical underpotential deposition (UPD), and the observed deposition potentials can be compared to those calculated by DFT. Theory is also used to learn more about structure than can be determined by analytical characterization alone. For example, density functional theory molecular dynamics (DFT-MD) was used to show that the core@shell configuration of Au@Pt DENs undergoes a surface reconstruction that dramatically affects its electrocatalytic properties. A separate Pd@Pt DENs study also revealed reorganization, in this case a core-shell inversion to a Pt@Pd structure. Understanding these types of structural changes is critical to building correlations between structure and catalytic function. Indeed, the second principal focus of the work described here is correlating structure and catalytic function through the combined use of theory and experiment. For example, the Au@Pt DENs system described earlier is used for the oxygen reduction reaction (ORR) as well as for the electro-oxidation of formic acid. The surface reorganization predicted by theory enhances our understanding of the catalytic measurements. In the case of formic acid oxidation, the deformed nanoparticle structure leads to reduced CO binding energy and therefore

  17. Probing the Mutational Interplay between Primary and Promiscuous Protein Functions: A Computational-Experimental Approach (United States)

    Garcia-Seisdedos, Hector; Ibarra-Molero, Beatriz; Sanchez-Ruiz, Jose M.


    Protein promiscuity is of considerable interest due its role in adaptive metabolic plasticity, its fundamental connection with molecular evolution and also because of its biotechnological applications. Current views on the relation between primary and promiscuous protein activities stem largely from laboratory evolution experiments aimed at increasing promiscuous activity levels. Here, on the other hand, we attempt to assess the main features of the simultaneous modulation of the primary and promiscuous functions during the course of natural evolution. The computational/experimental approach we propose for this task involves the following steps: a function-targeted, statistical coupling analysis of evolutionary data is used to determine a set of positions likely linked to the recruitment of a promiscuous activity for a new function; a combinatorial library of mutations on this set of positions is prepared and screened for both, the primary and the promiscuous activities; a partial-least-squares reconstruction of the full combinatorial space is carried out; finally, an approximation to the Pareto set of variants with optimal primary/promiscuous activities is derived. Application of the approach to the emergence of folding catalysis in thioredoxin scaffolds reveals an unanticipated scenario: diverse patterns of primary/promiscuous activity modulation are possible, including a moderate (but likely significant in a biological context) simultaneous enhancement of both activities. We show that this scenario can be most simply explained on the basis of the conformational diversity hypothesis, although alternative interpretations cannot be ruled out. Overall, the results reported may help clarify the mechanisms of the evolution of new functions. From a different viewpoint, the partial-least-squares-reconstruction/Pareto-set-prediction approach we have introduced provides the computational basis for an efficient directed-evolution protocol aimed at the simultaneous

  18. Commercial sexual exploitation of children

    National Research Council Canada - National Science Library

    Mauricio Rojas Betancur; Raquel Mendez Villamizar; Diana Lucía Moreno


      We study the sexual exploitation of children contributing to the understanding of risk and situations favouring the entry and permanence of children and adolescents from the reconstruction of the...

  19. Experimental approach to investigate the constrained recovery behavior of coiled monofilament polymer fibers (United States)

    Mendes, S. S.; Nunes, L. C. S.


    The aim of this work is to propose a new approach for investigating the thermo-mechanical behavior of coiled oriented polymer fibers with fixed ends and promote an understanding of the actuation response of coiled polymers in constrained recovery applications. In the proposed experimental methodology, a coiled fiber was pre-stretched by 50% and the distance between its ends remained constant, then it was subjected to a heating-cooling cycle ranging from 30 °C to 120 °C and the induced restoring force was measured. Based on these measurements, axial deformation and shear strain were obtained from full-field displacements extracted by the digital image correlation method from images of the coiled fiber. Three coiled fibers with different initial pitch angles were manufactured, and samples with lengths of 15 mm and 20 mm were tested. Bias angles and coil radius were also estimated using the experimental data associated with the helical spring theory. Results show that significant shape changes can be noticed above the glass transition temperature (47 °C), and these changes induce variation in the resultant forces. The effects of thermal softening and thermal contraction for a modest negative thermal expansion coefficient became evident at temperatures ranging from ∼47 °C to ∼90 °C, while the response of a coiled homochiral polymer fiber was achieved at temperatures close to 90 °C. During the cooling process, saturated states of the axial deformation and shear strain of the coiled fibers were observed at temperatures between 120 °C and 100 °C.

  20. Structures of discoidal high density lipoproteins: a combined computational-experimental approach. (United States)

    Gu, Feifei; Jones, Martin K; Chen, Jianguo; Patterson, James C; Catte, Andrea; Jerome, W Gray; Li, Ling; Segrest, Jere P


    Conversion of discoidal phospholipid (PL)-rich high density lipoprotein (HDL) to spheroidal cholesteryl ester-rich HDL is a central step in reverse cholesterol transport. A detailed understanding of this process and the atheroprotective role of apolipoprotein A-I (apoA-I) requires knowledge of the structure and dynamics of these various particles. This study, combining computation with experimentation, illuminates structural features of apoA-I allowing it to incorporate varying amounts of PL. Molecular dynamics simulated annealing of PL-rich HDL models containing unesterified cholesterol results in double belt structures with the same general saddle-shaped conformation of both our previous molecular dynamics simulations at 310 K and the x-ray structure of lipid-free apoA-I. Conversion from a discoidal to a saddle-shaped particle involves loss of helicity and formation of loops in opposing antiparallel parts of the double belt. During surface expansion caused by the temperature-jump step, the curved palmitoyloleoylphosphatidylcholine bilayer surfaces approach planarity. Relaxation back into saddle-shaped structures after cool down and equilibration further supports the saddle-shaped particle model. Our kinetic analyses of reconstituted particles demonstrate that PL-rich particles exist in discrete sizes corresponding to local energetic minima. Agreement of experimental and computational determinations of particle size/shape and apoA-I helicity provide additional support for the saddle-shaped particle model. Truncation experiments combined with simulations suggest that the N-terminal proline-rich domain of apoA-I influences the stability of PL-rich HDL particles. We propose that apoA-I incorporates increasing PL in the form of minimal surface bilayers through the incremental unwinding of an initially twisted saddle-shaped apoA-I double belt structure.

  1. A non-invasive experimental approach for surface temperature measurements on semi-crystalline thermoplastics (United States)

    Boztepe, Sinan; Gilblas, Remi; de Almeida, Olivier; Le Maoult, Yannick; Schmidt, Fabrice


    Most of the thermoforming processes of thermoplastic polymers and their composites are performed adopting a combined heating and forming stages at which a precursor is heated prior to the forming. This step is done in order to improve formability by softening the thermoplastic polymer. Due to low thermal conductivity and semi-transparency of polymers, infrared (IR) heating is widely used for thermoforming of such materials. Predictive radiation heat transfer models for temperature distributions are therefore critical for optimizations of thermoforming process. One of the key challenges is to build a predictive model including the physical background of radiation heat transfer phenomenon in semi-crystalline thermoplastics as their microcrystalline structure introduces an optically heterogeneous medium. In addition, the accuracy of a predictive model is required to be validated experimentally where IR thermography is one of the suitable methods for such a validation as it provides a non-invasive, full-field surface temperature measurement. Although IR cameras provide a non-invasive measurement, a key issue for obtaining a reliable measurement depends on the optical characteristics of a heated material and the operating spectral band of IR camera. It is desired that the surface of a material to be measured has a spectral band where the material behaves opaque and an employed IR camera operates in the corresponding band. In this study, the optical characteristics of the PO-based polymer are discussed and, an experimental approach is proposed in order to measure the surface temperature of the PO-based polymer via IR thermography. The preliminary analyses showed that IR thermographic measurements may not be simply performed on PO-based polymers and require a correction method as their semi-transparent medium introduce a challenge to obtain reliable surface temperature measurements.

  2. Numerical and experimental approaches to study soil transport and clogging in granular filters (United States)

    Kanarska, Y.; Smith, J. J.; Ezzedine, S. M.; Lomov, I.; Glascoe, L. G.


    Failure of a dam by erosion ranks among the most serious accidents in civil engineering. The best way to prevent internal erosion is using adequate granular filters in the transition areas where important hydraulic gradients can appear. In case of cracking and erosion, if the filter is capable of retaining the eroded particles, the crack will seal and the dam safety will be ensured. Numerical modeling has proved to be a cost-effective tool for improving our understanding of physical processes. Traditionally, the consideration of flow and particle transport in porous media has focused on treating the media as continuum. Practical models typically address flow and transport based on the Darcy's law as a function of a pressure gradient and a medium-dependent permeability parameter. Additional macroscopic constitutes describe porosity, and permeability changes during the migration of a suspension through porous media. However, most of them rely on empirical correlations, which often need to be recalibrated for each application. Grain-scale modeling can be used to gain insight into scale dependence of continuum macroscale parameters. A finite element numerical solution of the Navier-Stokes equations for fluid flow together with Lagrange multiplier technique for solid particles was applied to the simulation of soil filtration in the filter layers of gravity dam. The numerical approach was validated through comparison of numerical simulations with the experimental results of base soil particle clogging in the filter layers performed at ERDC. The numerical simulation correctly predicted flow and pressure decay due to particle clogging. The base soil particle distribution was almost identical to those measured in the laboratory experiment. It is believed that the agreement between simulations and experimental data demonstrates the applicability of the proposed approach for prediction of the soil transport and clogging in embankment dams. To get more precise understanding of

  3. Geomechanics of penetration : experimental and computational approaches : final report for LDRD project 38718.

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, Robert Douglas; Holcomb, David Joseph; Gettemy, Glen L.; Fossum, Arlo Frederick; Rivas, Raul R.; Bronowski, David R.; Preece, Dale S.


    The purpose of the present work is to increase our understanding of which properties of geomaterials most influence the penetration process with a goal of improving our predictive ability. Two primary approaches were followed: development of a realistic, constitutive model for geomaterials and designing an experimental approach to study penetration from the target's point of view. A realistic constitutive model, with parameters based on measurable properties, can be used for sensitivity analysis to determine the properties that are most important in influencing the penetration process. An immense literature exists that is devoted to the problem of predicting penetration into geomaterials or similar man-made materials such as concrete. Various formulations have been developed that use an analytic or more commonly, numerical, solution for the spherical or cylindrical cavity expansion as a sort of Green's function to establish the forces acting on a penetrator. This approach has had considerable success in modeling the behavior of penetrators, both as to path and depth of penetration. However the approach is not well adapted to the problem of understanding what is happening to the material being penetrated. Without a picture of the stress and strain state imposed on the highly deformed target material, it is not easy to determine what properties of the target are important in influencing the penetration process. We developed an experimental arrangement that allows greater control of the deformation than is possible in actual penetrator tests, yet approximates the deformation processes imposed by a penetrator. Using explosive line charges placed in a central borehole, we loaded cylindrical specimens in a manner equivalent to an increment of penetration, allowing the measurement of the associated strains and accelerations and the retrieval of specimens from the more-or-less intact cylinder. Results show clearly that the deformation zone is highly concentrated

  4. Similarity Based Kriging: A dimension-free approach for prediction and adaptive experimental design (United States)

    Ginsbourger, D.; Komara, R.


    Kriging has recently been revived as a powerful tool for predicting the outcome of costly numerical experiments and for guiding simulator evaluations, be it for optimization, inversion, or uncertainty quantification purposes. One key requirement for a successful application of Kriging is to formulate a suitable covariance (or variogram) model reflecting the (dis)similarity between locations or "inputs", in the sense that two inputs with a high covariance (or a low variogram) value are expected to correspond to close outcomes. Here we present an approach where the inputs can be very high-dimensional, like curves and maps, or even not identifiable as vectors, like shapes or geological scenarios. We extend the Kriging methodology to a very general set-up where a collection of inputs is given together with some measure of similarity between them, the response of interest is known only for a subset of the inputs, and predictions of the response are needed for the remaining inputs. The proposed Similarity Based Kriging (SBK) method relies on the combination of Multi-Dimensional Scaling (MDS) together with some well-chosen class of positive definite kernels. Possible degrees of freedom that govern the similarity measure and the MDS algorithms employed as well as the selected kernel make it a very versatile approach. Provided a relevant (dis)similarity measure between inputs is available, SBK appears as a simple and powerful method for predicting the outcome of complex experiments in a dimension-free set-up. After a global introduction to SBK, we will present results that concern the optimal tuning of MDS and kernel parameters. The potential of SBK for prediction and adaptive experimental design in geosciences will finally be illustrated using data sets from aquifer modelling and beyond.

  5. Simulation approach to charge sharing compensation algorithms with experimental cross-check (United States)

    Krzyżanowska, A.; Deptuch, G.; Maj, P.; Gryboś, P.; Szczygieł, R.


    Hybrid pixel detectors for X-ray imaging, working in a single photon counting mode, find applications in a variety of fields, such as medical imaging, material science or industry. However, charge sharing, which occurs when a photon hits a detector in the area between two or four pixels, becomes more significant with decreasing pixel size. If the charge generated when a photon interacts with a detector is collected by more than one pixel, the photon energy and the event position may be improperly detected. Therefore, algorithms for minimization of the impact of charge sharing on a pixel detector for X-ray detection need to be implemented. Firstly, such algorithms must be assessed on a simulation level. The goal is to implement the simulations in such a way that the simulation accuracy and simulation time are optimized. A model should be flexible enough so that it can be quickly adapted for other uses. We propose behavioral models implemented in the Cadence® Virtuoso® environment. This is a solution that enables fast validation of the system at the higher level of abstraction allowing deep verification. A readout channel of a chip is represented using parameterized behavioral blocks of different functionality, such as, a charge sensitive amplifier, shapers, discriminators, comparators. The inter-pixel connections are taken into account. This approach enables top-down design and optimization of parameters. The model was implemented in particular to test the C8P1 algorithm used in the Chase Jr. chip, however, due to its modular implementation, it can be easily adjusted to further test of the algorithms. The simulation approach is described and the simulation results are presented together with the experimental data obtained during synchrotron measurements for the Chase Jr. chip with the C8P1 algorithm implemented.

  6. Sustainable exploitation and management of aquatic resources

    DEFF Research Database (Denmark)

    Neuenfeldt, Stefan; Köster, Fritz


    DTU Aqua conducts research, provides advice,educates at university level and contributes toinnovation in sustainable exploitation andmanagement of aquatic resources. The vision of DTUAqua is to enable ecologically and economicallysustainable exploitation of aquatic resourcesapplying an integrated...... ecosystem approach whichutilizes synergies in natural and technical sciencedisciplines. DTU Aqua advises the Danish Ministry ofFood, Agriculture and Fisheries and other publicauthorities, the commercial fisheries, theaquaculture industry and international commissions.DTU Aqua deals with all types ofaquatic...... in the ocean and how these factors impact the living conditions formarine organisms. Population genetics aims at gaining knowledge on how to preserve and managebiodiversity sustainably. Individual biology deals with the biology of aquatic organisms and theirinteraction with other organisms...

  7. Teaching psychomotor skills to beginning nursing students using a web-enhanced approach: a quasi-experimental study. (United States)

    Salyers, Vincent L


    To begin to address the problem of psychomotor skills deficiencies observed in many new graduate nurses, a skills laboratory course was developed using a web-enhanced approach. In this quasi-experimental study, the control group attended weekly lectures, observed skill demonstrations by faculty, practiced skills, and were evaluated on skill performance. The experimental group learned course content using a web-enhanced approach. This allowed students to learn course material outside of class at times convenient for them, thus they had more time during class to perfect psychomotor skills. The experimental group performed better on the final cognitive examination. Students in the traditional sections were more satisfied with the course, however. It was concluded that a web-enhanced approach for teaching psychomotor skills can provide a valid alternative to traditional skills laboratory formats.

  8. Assessing Neurocognition via Gamified Experimental Logic: A Novel Approach to Simultaneous Acquisition of Multiple ERPs. (United States)

    Nair, Ajay K; Sasidharan, Arun; John, John P; Mehrotra, Seema; Kutty, Bindu M


    The present study describes the development of a neurocognitive paradigm: "Assessing Neurocognition via Gamified Experimental Logic" (ANGEL), for performing the parametric evaluation of multiple neurocognitive functions simultaneously. ANGEL employs an audiovisual sensory motor design for the acquisition of multiple event related potentials (ERPs)-the C1, P50, MMN, N1, N170, P2, N2pc, LRP, P300, and ERN. The ANGEL paradigm allows assessment of 10 neurocognitive variables over the course of three "game" levels of increasing complexity ranging from simple passive observation to complex discrimination and response in the presence of multiple distractors. The paradigm allows assessment of several levels of rapid decision making: speeded up response vs. response-inhibition; responses to easy vs. difficult tasks; responses based on gestalt perception of clear vs. ambiguous stimuli; and finally, responses with set shifting during challenging tasks. The paradigm has been tested using 18 healthy participants from both sexes and the possibilities of varied data analyses have been presented in this paper. The ANGEL approach provides an ecologically valid assessment (as compared to existing tools) that quickly yields a very rich dataset and helps to assess multiple ERPs that can be studied extensively to assess cognitive functions in health and disease conditions.

  9. Assessing Neurocognition via Gamified Experimental Logic: A novel approach to simultaneous acquisition of multiple ERPs

    Directory of Open Access Journals (Sweden)

    Ajay Kumar eNair


    Full Text Available The present study describes the development of a neurocognitive paradigm: ‘Assessing Neurocognition via Gamified Experimental Logic’ (ANGEL, for performing the parametric evaluation of multiple neurocognitive functions simultaneously. ANGEL employs an audiovisual sensory motor design for the acquisition of multiple event related potentials (ERPs - the C1, P50, MMN, N1, N170, P2, N2pc, LRP, P300 and ERN. The ANGEL paradigm allows assessment of ten neurocognitive variables over the course of three ‘game’ levels of increasing complexity ranging from simple passive observation to complex discrimination and response in the presence of multiple distractors. The paradigm allows assessment of several levels of rapid decision making: speeded up response vs response-inhibition; responses to easy vs difficult tasks; responses based on gestalt perception of clear vs ambiguous stimuli; and finally, responses with set shifting during challenging tasks. The paradigm has been tested using 18 healthy participants from both sexes and the possibilities of varied data analyses have been presented in this paper. The ANGEL approach provides an ecologically valid assessment (as compared to existing tools that quickly yields a very rich dataset and helps to assess multiple ERPs that can be studied extensively to assess cognitive functions in health and disease conditions.

  10. Development of the Digestive System-Experimental Challenges and Approaches of Infant Lipid Digestion. (United States)

    Abrahamse, Evan; Minekus, Mans; van Aken, George A; van de Heijning, Bert; Knol, Jan; Bartke, Nana; Oozeer, Raish; van der Beek, Eline M; Ludwig, Thomas


    At least during the first 6 months after birth, the nutrition of infants should ideally consist of human milk which provides 40-60 % of energy from lipids. Beyond energy, human milk also delivers lipids with a specific functionality, such as essential fatty acids (FA), phospholipids, and cholesterol. Healthy development, especially of the nervous and digestive systems, depends fundamentally on these. Epidemiological data suggest that human milk provides unique health benefits during early infancy that extend to long-lasting benefits. Preclinical findings show that qualitative changes in dietary lipids, i.e., lipid structure and FA composition, during early life may contribute to the reported long-term effects. Little is known in this respect about the development of digestive function and the digestion and absorption of lipids by the newborn. This review gives a detailed overview of the distinct functionalities that dietary lipids from human milk and infant formula provide and the profound differences in the physiology and biochemistry of lipid digestion between infants and adults. Fundamental mechanisms of infant lipid digestion can, however, almost exclusively be elucidated in vitro. Experimental approaches and their challenges are reviewed in depth.

  11. Surface enhanced Raman spectroscopic studies on aspirin : An experimental and theoretical approach (United States)

    Premkumar, R.; Premkumar, S.; Rekha, T. N.; Parameswari, A.; Mathavan, T.; Benial, A. Milton Franklin


    Surface enhanced Raman scattering (SERS) studies on aspirin molecule adsorbed on silver nanoparticles (AgNPs) were investigated by experimental and density functional theory approach. The AgNPs were synthesized by the solution-combustion method and characterized by the X-ray diffraction and high resolution-transmission electron microscopy techniques. The averaged particle size of synthesized AgNPs was calculated as ˜55 nm. The normal Raman spectrum (nRs) and SERS spectrum of the aspirin were recorded. The molecular structure of the aspirin and aspirin adsorbed on silver cluster were optimized by the DFT/ B3PW91 method with LanL2DZ basis set. The vibrational frequencies were calculated and assigned on the basis of potential energy distribution calculation. The calculated nRs and SERS frequencies were correlated well with the observed frequencies. The flat-on orientation was predicted from the nRs and SERS spectra, when the aspirin adsorbed on the AgNPs. Hence, the present studies lead to the understanding of adsorption process of aspirin on the AgNPs, which paves the way for biomedical applications.

  12. Fuzzy Supervisor Approach Design Based-Switching Controller for Pumping Station: Experimental Validation

    Directory of Open Access Journals (Sweden)

    Wael Chakchouk


    Full Text Available This paper proposes a discrete-time switching controller strategy for a hydraulic process pumping station. The proposed solution leads to improving control system performances with two tests: combination of Fuzzy-PD and PI controllers and Fuzzy-PID and PI controllers. The proposed design methodology is based on accurate model for pumping station (PS, which is developed in previous works using Fuzzy-C Means (FCM algorithm. The control law design is based on switching control; a fuzzy supervisor manages the switching from one to another and regulates the rate of participation of each order, in order to satisfy various objectives of a stable pumping station like the asymptotic stability of the tracking error. To validate the proposed solution, experimental tests are made and analyzed. Compared to the conventional PI and fuzzy logic (FL approaches, the results show that the switching controller allows exhibiting excellent transient response over a wide range of operating conditions and especially is easier to be implemented in practice.

  13. Surface enhanced Raman spectroscopic studies on aspirin : An experimental and theoretical approach

    Energy Technology Data Exchange (ETDEWEB)

    Premkumar, R.; Premkumar, S.; Parameswari, A.; Mathavan, T.; Benial, A. Milton Franklin, E-mail: [Department of Physics, N.M.S.S.V.N College, Madurai-625019, Tamilnadu, India. (India); Rekha, T. N. [PG and Research Department of Physics, Lady Doak College, Madurai-625 002, Tamilnadu, India. (India)


    Surface enhanced Raman scattering (SERS) studies on aspirin molecule adsorbed on silver nanoparticles (AgNPs) were investigated by experimental and density functional theory approach. The AgNPs were synthesized by the solution-combustion method and characterized by the X-ray diffraction and high resolution-transmission electron microscopy techniques. The averaged particle size of synthesized AgNPs was calculated as ∼55 nm. The normal Raman spectrum (nRs) and SERS spectrum of the aspirin were recorded. The molecular structure of the aspirin and aspirin adsorbed on silver cluster were optimized by the DFT/ B3PW91 method with LanL2DZ basis set. The vibrational frequencies were calculated and assigned on the basis of potential energy distribution calculation. The calculated nRs and SERS frequencies were correlated well with the observed frequencies. The flat-on orientation was predicted from the nRs and SERS spectra, when the aspirin adsorbed on the AgNPs. Hence, the present studies lead to the understanding of adsorption process of aspirin on the AgNPs, which paves the way for biomedical applications.

  14. Quantifying Dry Milling in Pharmaceutical Processing: A Review on Experimental and Modeling Approaches. (United States)

    Naik, Shivangi; Chaudhuri, Bodhisattwa


    Particle size reduction by mechanical means is an important unit operation in the pharmaceutical industry, used to improve flow, solubility, and in amorphization of drugs. It is usually achieved by the fracturing of particles under the action of applied energy. Despite being pervasive in the pharmaceutical field, it is one of the least understood processes owing to the complexity of material and process variables involved during milling. To comprehend the process, efforts should be focused on techniques that measure the particle size as well as the control the process. With the ongoing initiative of US FDA to encourage design in quality, the review is focused on some process analytical tools to characterize particle size distribution as well as process modeling tools to simulate particle size reduction. Additionally, an overview of some fundamental aspects related to milling is provided. To this end, the review is limited, mainly concentrating on some of experimental and modeling approaches used to quantify and understand the physics behind the process of dry milling. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  15. TWSME of a NiTi strip in free bending conditions: experimental and theoretical approach

    Directory of Open Access Journals (Sweden)

    A. Fortini


    Full Text Available This paper deals with the two-way shape memory effect (TWSME induced on a strip of a nearequiatomic NiTi alloy by means of the shape memory cycling training method. This procedure is based on the deformation in martensite state to reach the desired cold shape followed by cycling the temperature from above Af to below Mf. To this end, the sample was thermally treated to memorise a bent shape, thermomechanical trained as described and thermally cycled in unloaded conditions in order to study the stability of the induced TWSME. Heating to Af was reached by a hot air stream flow whereas cooling to Mf was achieved through natural convection. The evolution of the curvature with the increasing number of cycles was evaluated. The thermomechanical behaviour of the strip undergoing uniform bending was simulated using a one-dimensional phenomenological model based on stress and the temperature as external control variables. Both martensite and austenite volume fractions were chosen as internal parameters and kinetic laws were used in order to describe their evolution during phase transformations. The experimental findings are compared with the model simulation and a numerical prediction based on the approach proposed in [25].

  16. Yeast Phenomics: An Experimental Approach for Modeling Gene Interaction Networks that Buffer Disease

    Directory of Open Access Journals (Sweden)

    John L. Hartman


    Full Text Available The genome project increased appreciation of genetic complexity underlying disease phenotypes: many genes contribute each phenotype and each gene contributes multiple phenotypes. The aspiration of predicting common disease in individuals has evolved from seeking primary loci to marginal risk assignments based on many genes. Genetic interaction, defined as contributions to a phenotype that are dependent upon particular digenic allele combinations, could improve prediction of phenotype from complex genotype, but it is difficult to study in human populations. High throughput, systematic analysis of S. cerevisiae gene knockouts or knockdowns in the context of disease-relevant phenotypic perturbations provides a tractable experimental approach to derive gene interaction networks, in order to deduce by cross-species gene homology how phenotype is buffered against disease-risk genotypes. Yeast gene interaction network analysis to date has revealed biology more complex than previously imagined. This has motivated the development of more powerful yeast cell array phenotyping methods to globally model the role of gene interaction networks in modulating phenotypes (which we call yeast phenomic analysis. The article illustrates yeast phenomic technology, which is applied here to quantify gene X media interaction at higher resolution and supports use of a human-like media for future applications of yeast phenomics for modeling human disease.

  17. Theoretical and Experimental Approaches to the Dark Energy and the Cosmological Constant Problem

    CERN Document Server

    Borzou, Ahmad


    Theoretical and Experimental Approaches to the Dark Energy and theCosmological Constant ProblemAhmad Borzou, Ph.D.Advisor: Kenichi Hatakeyama, Ph.D.The cosmological constant problem is one of the most pressing problems ofphysics at this time. In this dissertation the problem and a set of widely-discussedtheoretical solutions to this problem are reviewed. It is shown that a recently developed Lorentz gauge theory of gravity can provide a natural solution. In this theorypresented here, the metric is not dynamical and it is shown that the Schwartzschildmetric is an exact solution. Also, it is proven that the de Sitter space is an exactvacuum solution and as a result the theory is able to explain the expansion of theuniverse with no need for dark energy. Renormalizability of the theory is studied aswell. It is also shown that, under a certain condition, the theory is power-countingrenormalizable.Supersymmetry provides an alternative solution to the cosmological problem aswell. The idea behind supersymmetry is rev...

  18. Yeast Phenomics: An Experimental Approach for Modeling Gene Interaction Networks that Buffer Disease. (United States)

    Hartman, John L; Stisher, Chandler; Outlaw, Darryl A; Guo, Jingyu; Shah, Najaf A; Tian, Dehua; Santos, Sean M; Rodgers, John W; White, Richard A


    The genome project increased appreciation of genetic complexity underlying disease phenotypes: many genes contribute each phenotype and each gene contributes multiple phenotypes. The aspiration of predicting common disease in individuals has evolved from seeking primary loci to marginal risk assignments based on many genes. Genetic interaction, defined as contributions to a phenotype that are dependent upon particular digenic allele combinations, could improve prediction of phenotype from complex genotype, but it is difficult to study in human populations. High throughput, systematic analysis of S. cerevisiae gene knockouts or knockdowns in the context of disease-relevant phenotypic perturbations provides a tractable experimental approach to derive gene interaction networks, in order to deduce by cross-species gene homology how phenotype is buffered against disease-risk genotypes. Yeast gene interaction network analysis to date has revealed biology more complex than previously imagined. This has motivated the development of more powerful yeast cell array phenotyping methods to globally model the role of gene interaction networks in modulating phenotypes (which we call yeast phenomic analysis). The article illustrates yeast phenomic technology, which is applied here to quantify gene X media interaction at higher resolution and supports use of a human-like media for future applications of yeast phenomics for modeling human disease.

  19. Meeting Report on Experimental Approaches to Evolution and Ecology Using Yeast and Other Model Systems. (United States)

    Jarosz, Daniel; Dudley, Aimée M


    The fourth EMBO-sponsored conference on Experimental Approaches to Evolution and Ecology Using Yeast and Other Model Systems (, was held at the EMBL in Heidelberg, Germany, October 19-23, 2016. The conference was organized by Judith Berman (Tel Aviv University), Maitreya Dunham (University of Washington), Jun-Yi Leu (Academia Sinica), and Lars Steinmetz (EMBL Heidelberg and Stanford University). The meeting attracted ~120 researchers from 28 countries and covered a wide range of topics in the fields of genetics, evolutionary biology, and ecology with a unifying focus on yeast as a model system. Attendees enjoyed the Keith Haring inspired yeast florescence microscopy artwork (Figure 1), a unique feature of the meeting since its inception, and the one-minute flash talks that catalyzed discussions at two vibrant poster sessions. The meeting coincided with the 20th anniversary of the publication describing the sequence of the first eukaryotic genome, Saccharomyces cerevisiae (Goffeau et al. 1996). Many of the conference talks focused on important questions about what is contained in the genome, how genomes evolve, and the architecture and behavior of communities of phenotypically and genotypically diverse microorganisms. Here, we summarize highlights of the research talks around these themes. Nearly all presentations focused on novel findings, and we refer the reader to relevant manuscripts that have subsequently been published. Copyright © 2017, G3: Genes, Genomes, Genetics.

  20. Meeting Report on Experimental Approaches to Evolution and Ecology Using Yeast and Other Model Systems

    Directory of Open Access Journals (Sweden)

    Daniel F. Jarosz


    Full Text Available The fourth EMBO-sponsored conference on Experimental Approaches to Evolution and Ecology Using Yeast and Other Model Systems (, was held at the EMBL in Heidelberg, Germany, October 19–23, 2016. The conference was organized by Judith Berman (Tel Aviv University, Maitreya Dunham (University of Washington, Jun-Yi Leu (Academia Sinica, and Lars Steinmetz (EMBL Heidelberg and Stanford University. The meeting attracted ∼120 researchers from 28 countries and covered a wide range of topics in the fields of genetics, evolutionary biology, and ecology, with a unifying focus on yeast as a model system. Attendees enjoyed the Keith Haring-inspired yeast florescence microscopy artwork (Figure 1, a unique feature of the meeting since its inception, and the 1 min flash talks that catalyzed discussions at two vibrant poster sessions. The meeting coincided with the 20th anniversary of the publication describing the sequence of the first eukaryotic genome, Saccharomyces cerevisiae. Many of the conference talks focused on important questions about what is contained in the genome, how genomes evolve, and the architecture and behavior of communities of phenotypically and genotypically diverse microorganisms. Here, we summarize highlights of the research talks around these themes. Nearly all presentations focused on novel findings, and we refer the reader to relevant manuscripts that have subsequently been published.

  1. Experimental testicular tissue banking to generate spermatogenesis in the future: A multidisciplinary team approach. (United States)

    Sadri-Ardekani, Hooman; McLean, Thomas W; Kogan, Stanley; Sirintrapun, Joseph; Crowell, Kathryn; Yousif, Mustafa Q; Hodges, Steve J; Petty, John; Pranikoff, Thomas; Sieren, Leah; Zeller, Kristen; Atala, Anthony


    Spermatogonial stem cell (SSC) loss due to cancer treatment, developmental disorder or genetic abnormality may cause permanent infertility. Cryopreservation of ejaculated sperm is an effective method of fertility preservation in adult males at risk of infertility. However this is not an option in pre-pubertal boys because spermatogenesis has not yet started, and it is difficult in adolescents who are not sexually mature. Therefore testicular tissue cryopreservation to preserve SSCs for future generation of spermatogenesis, either in vivo or in vitro, could be an option for these groups of patients. Although SSC transplantation has been successful in several species including non-human primates, it is still experimental in humans. There are several remaining concerns which need to be addressed before initiating trials of human SSC autotransplantation. Establishment of a testicular tissue banking system is a fundamental step towards using SSC technology as a fertility preservation method. It is important to understand the consultation, harvesting the testicular tissue, histological evaluation, cryopreservation, and long term storage aspects. We describe here a multidisciplinary approach to establish testicular tissue banking for males at risk of infertility. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Integrated Experimental Platforms to Study Blast Injuries: a Bottom-Up Approach (United States)

    Bo, Chiara


    Developing a cellular and molecular understanding of the nature of traumatic and post-traumatic effects of blast events on live biological samples is critical for improving clinical outcomes.1 To investigate the consequences of pressure waves upon cellular structures and the underlying physiological and biochemical changes, we are using an integrated approach to study the material and biological properties of cells, tissues and organs when subjected to extreme conditions. In particular we have developed a confined Split Hopkinson Pressure Bar (SHPB) system, which allows us to subject cells in suspension or in a monolayer to compression waves of the order of few MPa and duration of hundreds of microseconds.2 The chamber design also enables recovery of the biological samples for cellular and molecular analysis. Specifically, cell survivability, viability, proliferation and morphological changes are investigated post compression for different cell populations. The SHPB platform, coupled with Quasi-Static experiments, is also used to determine stress-strain curves of soft biological tissues under compression at low, medium and high strain rates. Samples are also examined using histological techniques to study macro- and microscopical changes induced by compression waves. Finally, a shock tube has been developed to replicate primary blast damage on organs (i.e. mice lungs) and cell monolayers by generating single or multiple air blast of the order of kPa and few milliseconds duration. This platform allows us to visualize post-traumatic morphological changes at the cellular level as a function of the stimulus pressure and duration as well as biomarker signatures of blast injuries. Adapting and integrating a variety of approaches with different experimental platforms allows us to sample a vast pressure-time space in terms of biological and structural damage that mimic blast injuries and also to determine which physical parameters (peak pressure, stimulus duration, impulse

  3. Exploitation et obligation de travailler

    Directory of Open Access Journals (Sweden)

    Pierre-Étienne Vandamme


    Full Text Available Cet article défend une définition de l’exploitation, restreinte aux relations de travail, en tentant d’une part d’expliciter une certaine compréhension de sens commun du concept (rémunération inéquitable en fonction du travail presté, et d’autre part d’échapper aux difficultés qui ont affecté la définition marxiste traditionnelle de l’exploitation comme extorsion de la plus-value (dans ses diverses variantes. Il explore ainsi le lien entre l’exploitation et l’obligation matérielle de travailler pour subvenir à ses besoins fondamentaux. Après avoir mis en garde contre les politiques d’activation des chômeurs, il conclut que l’exploitation est un phénomène contre lequel on peut lutter à l’aide de mécanismes relativement simples, même dans les sociétés capitalistes. Il rappelle toutefois que cela ne suffit pas à réaliser la justice sociale, resituant l’exploitation parmi d’autres enjeux fondamentaux pour une philosophie politique égalitariste

  4. Mainstreaming Caenorhabditis elegans in experimental evolution. (United States)

    Gray, Jeremy C; Cutter, Asher D


    Experimental evolution provides a powerful manipulative tool for probing evolutionary process and mechanism. As this approach to hypothesis testing has taken purchase in biology, so too has the number of experimental systems that use it, each with its own unique strengths and weaknesses. The depth of biological knowledge about Caenorhabditis nematodes, combined with their laboratory tractability, positions them well for exploiting experimental evolution in animal systems to understand deep questions in evolution and ecology, as well as in molecular genetics and systems biology. To date, Caenorhabditis elegans and related species have proved themselves in experimental evolution studies of the process of mutation, host-pathogen coevolution, mating system evolution and life-history theory. Yet these organisms are not broadly recognized for their utility for evolution experiments and remain underexploited. Here, we outline this experimental evolution work undertaken so far in Caenorhabditis, detail simple methodological tricks that can be exploited and identify research areas that are ripe for future discovery.

  5. Mainstreaming Caenorhabditis elegans in experimental evolution (United States)

    Gray, Jeremy C.; Cutter, Asher D.


    Experimental evolution provides a powerful manipulative tool for probing evolutionary process and mechanism. As this approach to hypothesis testing has taken purchase in biology, so too has the number of experimental systems that use it, each with its own unique strengths and weaknesses. The depth of biological knowledge about Caenorhabditis nematodes, combined with their laboratory tractability, positions them well for exploiting experimental evolution in animal systems to understand deep questions in evolution and ecology, as well as in molecular genetics and systems biology. To date, Caenorhabditis elegans and related species have proved themselves in experimental evolution studies of the process of mutation, host–pathogen coevolution, mating system evolution and life-history theory. Yet these organisms are not broadly recognized for their utility for evolution experiments and remain underexploited. Here, we outline this experimental evolution work undertaken so far in Caenorhabditis, detail simple methodological tricks that can be exploited and identify research areas that are ripe for future discovery. PMID:24430852

  6. Exploit and ignore the consequences: A mother of planetary issues. (United States)

    Moustafa, Khaled


    Many environmental and planetary issues are due to an exploitation strategy based on exploit, consume and ignore the consequences. As many natural and environmental resources are limited in time and space, such exploitation approach causes important damages on earth, in the sea and maybe soon in the space. To sustain conditions under which humans and other living species can coexist in productive and dynamic harmony with their environments, terrestrial and space exploration programs may need to be based on 'scrutinize the consequences, prepare adequate solutions and then, only then, exploit'. Otherwise, the exploitation of planetary resources may put the environmental stability and sustainability at a higher risk than it is currently predicted. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Simulated population responses of common carp to commercial exploitation

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Michael J.; Hennen, Matthew J.; Brown, Michael L.


    Common carp Cyprinus carpio is a widespread invasive species that can become highly abundant and impose deleterious ecosystem effects. Thus, aquatic resource managers are interested in controlling common carp populations. Control of invasive common carp populations is difficult, due in part to the inherent uncertainty of how populations respond to exploitation. To understand how common carp populations respond to exploitation, we evaluated common carp population dynamics (recruitment, growth, and mortality) in three natural lakes in eastern South Dakota. Common carp exhibited similar population dynamics across these three systems that were characterized by consistent recruitment (ages 3 to 15 years present), fast growth (K = 0.37 to 0.59), and low mortality (A = 1 to 7%). We then modeled the effects of commercial exploitation on size structure, abundance, and egg production to determine its utility as a management tool to control populations. All three populations responded similarly to exploitation simulations with a 575-mm length restriction, representing commercial gear selectivity. Simulated common carp size structure modestly declined (9 to 37%) in all simulations. Abundance of common carp declined dramatically (28 to 56%) at low levels of exploitation (0 to 20%) but exploitation >40% had little additive effect and populations were only reduced by 49 to 79% despite high exploitation (>90%). Maximum lifetime egg production was reduced from 77 to 89% at a moderate level of exploitation (40%), indicating the potential for recruitment overfishing. Exploitation further reduced common carp size structure, abundance, and egg production when simulations were not size selective. Our results provide insights to how common carp populations may respond to exploitation. Although commercial exploitation may be able to partially control populations, an integrated removal approach that removes all sizes of common carp has a greater chance of controlling population abundance

  8. A combined experimental and mathematical approach for molecular-based optimization of irinotecan circadian delivery.

    Directory of Open Access Journals (Sweden)

    Annabelle Ballesta


    Full Text Available Circadian timing largely modifies efficacy and toxicity of many anticancer drugs. Recent findings suggest that optimal circadian delivery patterns depend on the patient genetic background. We present here a combined experimental and mathematical approach for the design of chronomodulated administration schedules tailored to the patient molecular profile. As a proof of concept we optimized exposure of Caco-2 colon cancer cells to irinotecan (CPT11, a cytotoxic drug approved for the treatment of colorectal cancer. CPT11 was bioactivated into SN38 and its efflux was mediated by ATP-Binding-Cassette (ABC transporters in Caco-2 cells. After cell synchronization with a serum shock defining Circadian Time (CT 0, circadian rhythms with a period of 26 h 50 (SD 63 min were observed in the mRNA expression of clock genes REV-ERBα, PER2, BMAL1, the drug target topoisomerase 1 (TOP1, the activation enzyme carboxylesterase 2 (CES2, the deactivation enzyme UDP-glucuronosyltransferase 1, polypeptide A1 (UGT1A1, and efflux transporters ABCB1, ABCC1, ABCC2 and ABCG2. DNA-bound TOP1 protein amount in presence of CPT11, a marker of the drug PD, also displayed circadian variations. A mathematical model of CPT11 molecular pharmacokinetics-pharmacodynamics (PK-PD was designed and fitted to experimental data. It predicted that CPT11 bioactivation was the main determinant of CPT11 PD circadian rhythm. We then adopted the therapeutics strategy of maximizing efficacy in non-synchronized cells, considered as cancer cells, under a constraint of maximum toxicity in synchronized cells, representing healthy ones. We considered exposure schemes in the form of an initial concentration of CPT11 given at a particular CT, over a duration ranging from 1 to 27 h. For any dose of CPT11, optimal exposure durations varied from 3h40 to 7h10. Optimal schemes started between CT2h10 and CT2h30, a time interval corresponding to 1h30 to 1h50 before the nadir of CPT11 bioactivation rhythm in

  9. Efficient Discovery of Novel Multicomponent Mixtures for Hydrogen Storage: A Combined Computational/Experimental Approach

    Energy Technology Data Exchange (ETDEWEB)

    Wolverton, Christopher [Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering; Ozolins, Vidvuds [Univ. of California, Los Angeles, CA (United States). Dept. of Materials Science and Engineering; Kung, Harold H. [Northwestern Univ., Evanston, IL (United States). Dept. of Chemical and Biological Engineering; Yang, Jun [Ford Scientific Research Lab., Dearborn, MI (United States); Hwang, Sonjong [California Inst. of Technology (CalTech), Pasadena, CA (United States). Dept. of Chemistry and Chemical Engineering; Shore, Sheldon [The Ohio State Univ., Columbus, OH (United States). Dept. of Chemistry and Biochemistry


    The objective of the proposed program is to discover novel mixed hydrides for hydrogen storage, which enable the DOE 2010 system-level goals. Our goal is to find a material that desorbs 8.5 wt.% H2 or more at temperatures below 85°C. The research program will combine first-principles calculations of reaction thermodynamics and kinetics with material and catalyst synthesis, testing, and characterization. We will combine materials from distinct categories (e.g., chemical and complex hydrides) to form novel multicomponent reactions. Systems to be studied include mixtures of complex hydrides and chemical hydrides [e.g. LiNH2+NH3BH3] and nitrogen-hydrogen based borohydrides [e.g. Al(BH4)3(NH3)3]. The 2010 and 2015 FreedomCAR/DOE targets for hydrogen storage systems are very challenging, and cannot be met with existing materials. The vast majority of the work to date has delineated materials into various classes, e.g., complex and metal hydrides, chemical hydrides, and sorbents. However, very recent studies indicate that mixtures of storage materials, particularly mixtures between various classes, hold promise to achieve technological attributes that materials within an individual class cannot reach. Our project involves a systematic, rational approach to designing novel multicomponent mixtures of materials with fast hydrogenation/dehydrogenation kinetics and favorable thermodynamics using a combination of state-of-the-art scientific computing and experimentation. We will use the accurate predictive power of first-principles modeling to understand the thermodynamic and microscopic kinetic processes involved in hydrogen release and uptake and to design new material/catalyst systems with improved properties. Detailed characterization and atomic-scale catalysis experiments will elucidate the effect of dopants and nanoscale catalysts in achieving fast kinetics and reversibility. And

  10. Development and Comparison of Techniques for Generating Permeability Maps using Independent Experimental Approaches (United States)

    Hingerl, Ferdinand; Romanenko, Konstantin; Pini, Ronny; Balcom, Bruce; Benson, Sally


    We have developed and evaluated methods for creating voxel-based 3D permeability maps of a heterogeneous sandstone sample using independent experimental data from single phase flow (Magnetic Resonance Imaging, MRI) and two-phase flow (X-ray Computed Tomography, CT) measurements. Fluid velocities computed from the generated permeability maps using computational fluid dynamics simulations fit measured velocities very well and significantly outperform empirical porosity-permeability relations, such as the Kozeny-Carman equation. Acquiring images on the meso-scale from porous rocks using MRI has till recently been a great challenge, due to short spin relaxation times and large field gradients within the sample. The combination of the 13-interval Alternating-Pulsed-Gradient Stimulated-Echo (APGSTE) scheme with three-dimensional Single Point Ramped Imaging with T1 Enhancement (SPRITE) - a technique recently developed at the UNB MRI Center - can overcome these challenges and enables obtaining quantitative 3 dimensional maps of porosities and fluid velocities. Using porosity and (single-phase) velocity maps from MRI and (multi-phase) saturation maps from CT measurements, we employed three different techniques to obtain permeability maps. In the first approach, we applied the Kozeny-Carman relationship to porosities measured using MRI. In the second approach, we computed permeabilities using a J-Leverett scaling method, which is based on saturation maps obtained from N2-H2O multi-phase experiments. The third set of permeabilities was generated using a new inverse iterative-updating technique, which is based on porosities and measured velocities obtained in single-phase flow experiments. The resulting three permeability maps provided then input for computational fluid dynamics simulations - employing the Stanford CFD code AD-GPRS - to generate velocity maps, which were compared to velocity maps measured by MRI. The J-Leveret scaling method and the iterative-updating method

  11. Sensory perception in cetaceans: Part II – Promising experimental approaches to study chemoreception in dolphins

    Directory of Open Access Journals (Sweden)

    Dorothee eKremers


    Full Text Available Chemosensory perception in cetaceans remains an intriguing issue as morphological, neuroanatomical and genetic studies draw unclear conclusions, while behavioral data suggest that dolphins may use it for food selection or socio-sexual interactions. Experimental approaches have been scarce due to the practical difficulties of testing chemoreception in wild dolphins. Go/no-go tasks are one elegant way to investigate discrimination abilities; however, they require to train the animals, thus preventing spontaneous responses and hence the expression of preferences. Here, we aimed at testing potential spontaneous responses to chemical stimuli and developed novel procedures. First, we conducted a study to test whether captive dolphins respond to a biologically relevant smell. Therefore, we placed dead fish within an opaque barrel at the border of the pool and counted the number of respirations at proximity as an indicator of investigation. The same dead fishes were presented several times during experiments lasting three consecutive days. From the second day on (i.e. when the odor composition changed, dolphins breathed more often close to the fish-smelling barrel than close to the visually identical but empty control barrel. Second, we conducted a study to test whether dolphins are able to discriminate food flavors. Captive dolphins are commonly provided with ice cubes as a source of enrichment. We took this opportunity to provide ice cubes with different flavors and to compare the reaction to these different flavors as a measure of discrimination. Hence, we used the latency of return to the ice cube begging spot as a measure of discrimination from the previous ice cube flavor. Thus, our method used a non-invasive and easily replicable technique based on the spontaneous begging responses of dolphins toward more or less attractive items bearing biological relevance. The procedures used enabled us to show that dolphins may discriminate odors and flavors

  12. An experimental approach for science laboratories in the contest of science of primary education degree course

    Directory of Open Access Journals (Sweden)

    Giacomo Bozzo


    Full Text Available International literature in science education has shown the importance of introducing scientific studies in primary school, in order to give pupils competences and skills necessary for their life. Consequently, prospective primary teachers need to improve their scientific knowledge and to plan new experimental activities for primary school students. In this context, we have planned an educational learning path for prospective primary teachers, focused on specific conceptual knows of kinematics. The proposed activities are based on an empirical approach, avoiding in the first step any formal introduction of the observed phenomena, which could be difficult to understand, especially for students of science of primary education degree course. In this context, the educational technologies have given a fundamental support, since they have offered to prospective teachers the possibility to focus their attention only on the involved physics concepts and principles.Un approccio sperimentale per i laboratori scientifici nei corsi di laurea in Scienze della Formazione PrimariaStudi recenti hanno evidenziato la necessità di introdurre le discipline scientifiche sin dalla scuola primaria, per consentire alle future generazioni di vivere in modo critico e consapevole nel mondo reale. I futuri insegnanti hanno, quindi, la necessità di approfondire le loro conoscenze in ambito scientifico e di progettare valide attività laboratoriali per gli alunni di scuola primaria. In questo contesto si inserisce la nostra azione formativa rivolta agli studenti di Scienze della Formazione Primaria (SFP, mirata ad affrontare alcune difficoltà nell’apprendimento della Fisica, ben note in letteratura. L’attività didattica proposta è basata sull’osservazione diretta dei fenomeni fisici, evitando, nella fase iniziale, ogni genere di introduzione formale che possa risultare di difficile comprensione per gli studenti di SFP. Il supporto delle tecnologie didattiche ha

  13. Percutaneous transcholecystic approach for an experiment of biliary stent placement: an experimental study in dogs

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Tae Seok [Medical School of Gachon, Inchon (Korea, Republic of); Song, Ho Young; Lim, Jin Oh; Ko, Gi Young; Sung, Kyu Bo; Kim, Tae Hyung; Lee, Ho Jung [College of Medicine, Ulsan Univ., Seoul (Korea, Republic of)


    To determine, in an experimental study of biliary stent placement, the usefulness and safety of the percutaneous transcholecystic approach and the patency of a newly designed biliary stent. A stent made of 0.15-mm-thick nitinol wire, and 10 mm in diameter and 2 cm in length, was loaded in an introducer with an 8-F outer diameter. The gallbladders of seven mongrel dogs were punctured with a 16-G angiocath needle under sonographic guidance, and cholangiography was performed. After anchoring the anterior wall of the gallbladder to the abdominal wall using a T-fastener, the gallbladder body was punctured again under fluoroscopic guidance. The cystic and common bile ducts were selected using a 0.035-inch guide wire and a cobra catheter, and the stent was placed in the common bile duct. Post-stenting cholangiography was undertaken, and an 8.5-F drainage tube was inserted in the gallbladder. Two dogs were followed-up and sacrificed at 2,4 and 8 weeks after stent placement, respectively, and the other expired 2 days after stent placement. Follow-up cholangiograms were obtained before aninmal was sacrified, and a pathologic examination was performed. Stent placement was technically successful in all cases. One dog expired 2 days after placement because of bile peritonitis due to migration of the drainage tube into the peritoneal cavity, but the other six remained healthy during the follow-up period. Cholangiography performed before the sacrifice of each dog showed that the stents were patent. Pathologic examination revealed the proliferation of granulation tissue at 2 weeks, and complete endothelialization over the stents by granulation tissue at 8 weeks. Percutaneous transcholecystic biliary stent placement appears to be safe, easy and useful. After placement, the stent was patent during the follow-period.

  14. Design of high productivity antibody capture by protein A chromatography using an integrated experimental and modeling approach. (United States)

    Ng, Candy K S; Osuna-Sanchez, Hector; Valéry, Eric; Sørensen, Eva; Bracewell, Daniel G


    An integrated experimental and modeling approach for the design of high productivity protein A chromatography is presented to maximize productivity in bioproduct manufacture. The approach consists of four steps: (1) small-scale experimentation, (2) model parameter estimation, (3) productivity optimization and (4) model validation with process verification. The integrated use of process experimentation and modeling enables fewer experiments to be performed, and thus minimizes the time and materials required in order to gain process understanding, which is of key importance during process development. The application of the approach is demonstrated for the capture of antibody by a novel silica-based high performance protein A adsorbent named AbSolute. In the example, a series of pulse injections and breakthrough experiments were performed to develop a lumped parameter model, which was then used to find the best design that optimizes the productivity of a batch protein A chromatographic process for human IgG capture. An optimum productivity of 2.9 kg L⁻¹ day⁻¹ for a column of 5mm diameter and 8.5 cm length was predicted, and subsequently verified experimentally, completing the whole process design approach in only 75 person-hours (or approximately 2 weeks). Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Open Experimentation on Phenomena of Chemical Reactions via the Learning Company Approach in Early Secondary Chemistry Education (United States)

    Beck, Katharina; Witteck, Torsten; Eilks, Ingo


    Presented is a case study on the implementation of open and inquiry-type experimentation in early German secondary chemistry education. The teaching strategy discussed follows the learning company approach. Originally adopted from vocational education, the learning company method is used to redirect lab-oriented classroom practice towards a more…

  16. An experimental approach to the immuno-modulatory basis of host-parasite local adaptation in tapeworm-infected sticklebacks. (United States)

    Hamley, Madeleine; Franke, Frederik; Kurtz, Joachim; Scharsack, Jörn Peter


    The evolutionary arms race of hosts and parasites often results in adaptations, which may differ between populations. Investigation of such local adaptation becomes increasingly important to understand dynamics of host-parasite interactions and co-evolution. To this end we performed an infection experiment involving pairs of three-spined sticklebacks and their tapeworm parasite Schistocephalus solidus from three geographically separated origins (Germany, Spain and Iceland) in a fully-crossed design for sympatric and allopatric host/parasite combinations. We hypothesized that local adaptation of the hosts results in differences in parasite resistance with variation in parasite infection rates and leukocyte activation, whereas parasites from different origins might differ in virulence reflected in host exploitation rates (parasite indices) and S. solidus excretory-secretory products (SsESP) involved in immune manipulation. In our experimental infections, sticklebacks from Iceland were more resistant to S. solidus infection compared to Spanish and German sticklebacks. Higher resistance of Icelandic sticklebacks seemed to depend on adaptive immunity, whereas sticklebacks of German origin, which were more heavily afflicted by S. solidus, showed elevated activity of innate immune traits. German S. solidus were less successful in infecting and exploiting allopatric hosts compared to their Icelandic and Spanish conspecifics. Nevertheless, exclusively SsESP from German S. solidus triggered significant in vitro responses of leukocytes from naïve sticklebacks. Interestingly, parasite indices were almost identical across the sympatric combinations. Differences in host resistance and parasite virulence between the origins were most evident in allopatric combinations and were consistent within origin; i.e. Icelandic sticklebacks were more resistant and their S. solidus were more virulent in all allopatric combinations, whereas German sticklebacks were less resistant and

  17. Experimental Medicine in Psychiatry New Approaches in Schizophrenia, Depression and Cognition. (United States)

    Dawson, Gerard R

    The use of experimental medicine studies to bridge the gap between Phase 1 and 2 drug trials and so to enhance translation of basic neuroscience studies using experimental animals to the clinic is proposed. Illustrative examples are provided for affective disorders and schizophrenia in relation also to cognitive dysfunction.

  18. An Experimental Approach to the Improvement of the Typographic Design of Textbooks. (United States)

    Wendt, Dirk


    A lesson from a physics textbook for secondary students was redesigned in three versions and given to 600 students. Results of achievement measures suggested that one of the experimental versions (which stressed the visual aspects of the printed page) was superior to the standard and the other experimental versions. (GT)

  19. Identifying and characterising the different structural length scales in liquids and glasses: an experimental approach. (United States)

    Salmon, Philip S; Zeidler, Anita


    The structure of several network-forming liquids and glasses is considered, where a focus is placed on the detailed information that is made available by using the method of neutron diffraction with isotope substitution (NDIS). In the case of binary network glass-forming materials with the MX2 stoichiometry (e.g. GeO2, GeSe2, ZnCl2), two different length scales at distances greater than the nearest-neighbour distance manifest themselves by peaks in the measured diffraction patterns. The network properties are influenced by a competition between the ordering on these "intermediate" and "extended" length scales, which can be manipulated by changing the chemical identity of the atomic constituents or by varying state parameters such as the temperature and pressure. The extended-range ordering, which describes the decay of the pair-correlation functions at large-r, can be represented by making a pole analysis of the Ornstein-Zernike equations, an approach that can also be used to describe the large-r behaviour of the pair-correlation functions for liquid and amorphous metals where packing constraints are important. The first applications are then described of the NDIS method to measure the detailed structure of aerodynamically-levitated laser-heated droplets of "fragile" glass-forming liquid oxides (CaAl2O4 and CaSiO3) at high-temperatures (~2000 K) and the structure of a "strong" network-forming glass (GeO2) under pressures ranging from ambient to ~8 GPa. The high-temperature experiments show structural changes on multiple length scales when the oxides are vitrified. The high-pressure experiment offers insight into the density-driven mechanisms of network collapse in GeO2 glass, and parallels are drawn with the high-pressure behaviour of silica glass. Finally, the hydrogen-bonded network of water is considered, where the first application of the method of oxygen NDIS is used to measure the structures of light versus heavy water and a difference of approximately equal

  20. Calcium and IP3 dynamics in cardiac myocytes: Experimental and computational perspectives and approaches

    Directory of Open Access Journals (Sweden)

    Felix eHohendanner


    Full Text Available Calcium plays a crucial role in excitation-contraction coupling (ECC, but it is also a pivotal second messenger activating Ca2+-dependent transcription factors in a process termed excitation-transcription coupling (ETC. Evidence accumulated over the past decade indicates a pivotal role of inositol 1,4,5-trisphosphate receptor (IP3R-mediated Ca2+ release in the regulation of cytosolic and nuclear Ca2+ signals. IP3 is generated by stimulation of plasma membrane receptors that couple to phospholipase C (PLC, liberating IP3 from phosphatidylinositol 4,5-bisphosphate (PIP2. An intriguing aspect of IP3 signaling is the presence of the entire PIP2-PLC-IP3 signaling cascade as well as the presence of IP3Rs at the inner and outer membranes of the nuclear envelope (NE which functions as a Ca2+ store. The observation that the nucleus is surrounded by its own putative Ca2+ store raises the possibility that nuclear IP3-dependent Ca2+ release plays a critical role in ETC. This provides a potential mechanism of regulation that acts locally and autonomously from the global cytosolic Ca2+ signal underlying ECC. Moreover, there is evidence that: (i the sarcoplasmic reticulum (SR and NE are a single contiguous Ca2+ store; (ii the nuclear pore complex is the major gateway for Ca2+ and macromolecules to pass between the cytosol and the nucleoplasm; (iii the inner membrane of the NE hosts key Ca2+ handling proteins including the Na+/Ca2+ exchanger (NCX/GM1 complex, ryanodine receptors (RyRs, nicotinic acid adenine dinucleotide phosphate receptors (NAADPRs, Na+/K+ ATPase and Na+/H+ exchanger. Thus, it appears that the nucleus represents a Ca2+ signaling domain equipped with its own ion channels and transporters that allow for complex local Ca2+ signals. Many experimental and modeling approaches have been used for the study of intracellular Ca2+ signaling but the key to understanding of the dual role of Ca2+ mediating ECC and ECT lays in quantitative differences of

  1. Experimental approach and modelling of the mechanical behaviour of graphite fuel elements subjected to compression pulses

    Directory of Open Access Journals (Sweden)

    Forquin P.


    particulate-graphite and the corresponding standard deviation. The behaviour being non linear before failure, a numerical simulation has been conducted to build the relation between the applied load and the maximum tensile stress. A statistical approach applied to experimental data allows deducing the mean tensile strength (about 2.5 MPa and the scatter of failure stresses (Weibull modulus m = 12.

  2. Experimental Systems-Biology Approaches for Clostridia-Based Bioenergy Production

    Energy Technology Data Exchange (ETDEWEB)

    Papoutsakis, Elefterios [Univ. of Delaware, Newark, DE (United States)


    This is the final project report for project "Experimental Systems-Biology Approaches for Clostridia-Based Bioenergy Production" for the funding period of 9/1/12 to 2/28/2015 (three years with a 6-month no-cost extension) OVERVIEW AND PROJECT GOALS The bottleneck of achieving higher rates and titers of toxic metabolites (such as solvents and carboxylic acids that can used as biofuels or biofuel precursors) can be overcome by engineering the stress response system. Thus, understanding and modeling the response of cells to toxic metabolites is a problem of great fundamental and practical significance. In this project, our goal is to dissect at the molecular systems level and build models (conceptual and quantitative) for the stress response of C. acetobutylicum (Cac) to its two toxic metabolites: butanol (BuOH) and butyrate (BA). Transcriptional (RNAseq and microarray based), proteomic and fluxomic data and their analysis are key requirements for this goal. Transcriptional data from mid-exponential cultures of Cac under 4 different levels of BuOH and BA stress was obtained using both microarrays (Papoutsakis group) and deep sequencing (RNAseq; Meyers and Papoutsakis groups). These two sets of data do not only serve to validate each other, but are also used for identification of stress-induced changes in transcript levels, small regulatory RNAs, & in transcriptional start sites. Quantitative proteomic data (Lee group), collected using the iTRAQ technology, are essential for understanding of protein levels and turnover under stress and the various protein-protein interactions that orchestrate the stress response. Metabolic flux changes (Antoniewicz group) of core pathways, which provide important information on the re-allocation of energy and carbon resources under metabolite stress, were examined using 13C-labelled chemicals. Omics data are integrated at different levels and scales. At the metabolic-pathway level, omics data are integrated into a 2nd generation genome

  3. Consistency from the perspective of an experimental systems approach to the sciences and their epistemic objects

    Directory of Open Access Journals (Sweden)

    Hans-Jörg Rheinberger


    Full Text Available It is generally accepted that the development of the modern sciences is rooted in experiment. Yet for a long time, experimentation did not occupy a prominent role, neither in philosophy nor in history of science. With the 'practical turn' in studying the sciences and their history, this has begun to change. This paper is concerned with systems and cultures of experimentation and the consistencies that are generated within such systems and cultures. The first part of the paper exposes the forms of historical and structural coherence that characterize the experimental exploration of epistemic objects. In the second part, a particular experimental culture in the life sciences is briefly described as an example. A survey will be given of what it means and what it takes to analyze biological functions in the test tube.

  4. Teotihuacan, tepeapulco, and obsidian exploitation. (United States)

    Charlton, T H


    Current cultural ecological models of the development of civilization in central Mexico emphasize the role of subsistence production techniques and organization. The recent use of established and productive archeological surface survey techniques along natural corridors of communication between favorable niches for cultural development within the Central Mexican symbiotic region resulted in the location of sites that indicate an early development of a decentralized resource exploitation, manufacturing, and exchange network. The association of the development of this system with Teotihuacán indicates the importance such nonsubsistence production and exchange had in the evolution of this first central Mexican civilization. The later expansion of Teotihuacán into more distant areas of Mesoamerica was based on this resource exploitation model. Later civilizations centered at Tula and Tenochtitlán also used such a model in their expansion.

  5. Dark matters: exploitation as cooperation. (United States)

    Dasgupta, Partha


    The empirical literature on human cooperation contains studies of communitarian institutions that govern the provision of public goods and management of common property resources in poor countries. Scholars studying those institutions have frequently used the Prisoners' Dilemma game as their theoretical tool-kit. But neither the provision of local public goods nor the management of local common property resources involves the Prisoners' Dilemma. That has implications for our reading of communitarian institutions. By applying a fundamental result in the theory of repeated games to a model of local common property resources, it is shown that communitarian institutions can harbour exploitation of fellow members, something that would not be possible in societies where cooperation amounts to overcoming the Prisoners' Dilemma. The conclusion we should draw is that exploitation can masquerade as cooperation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Direct Determination of Absolute Configuration of Methyl-Substituted Phenyloxiranes: A Combined Experimental and Theoretical Approach

    DEFF Research Database (Denmark)

    Fristrup, Peter; Lassen, Peter Rygaard; Johannessen, Christian


    Three possible methyl-substituted phenyloxiranes have been synthesized in enantioenriched form (89-99% enantiomeric excess (ee)), and their vibrational absorption (VA) and vibrational circular dichroism (VCD) spectra have been recorded. The experimental spectra are compared to theoretical spectra...... by comparing experimental and theoretical spectra. In addition, we have been able to document the changes that occur both in structures and in the VA and VCD spectra due to substituent effects on the oxirane ring....

  7. Statistical Approaches in Analysis of Variance: from Random Arrangements to Latin Square Experimental Design


    Radu E. SESTRAŞ; Lorentz JÄNTSCHI; Sorana D. BOLBOACĂ


    Background: The choices of experimental design as well as of statisticalanalysis are of huge importance in field experiments. These are necessary tobe correctly in order to obtain the best possible precision of the results. Therandom arrangements, randomized blocks and Latin square designs werereviewed and analyzed from the statistical perspective of error analysis.Material and Method: Random arrangements, randomized block and Latinsquares experimental designs were used as field experiments. ...

  8. Sample-based approach can outperform the classical dynamical analysis - experimental confirmation of the basin stability method. (United States)

    Brzeski, P; Wojewoda, J; Kapitaniak, T; Kurths, J; Perlikowski, P


    In this paper we show the first broad experimental confirmation of the basin stability approach. The basin stability is one of the sample-based approach methods for analysis of the complex, multidimensional dynamical systems. We show that investigated method is a reliable tool for the analysis of dynamical systems and we prove that it has a significant advantages which make it appropriate for many applications in which classical analysis methods are difficult to apply. We study theoretically and experimentally the dynamics of a forced double pendulum. We examine the ranges of stability for nine different solutions of the system in a two parameter space, namely the amplitude and the frequency of excitation. We apply the path-following and the extended basin stability methods (Brzeski et al., Meccanica 51(11), 2016) and we verify obtained theoretical results in experimental investigations. Comparison of the presented results show that the sample-based approach offers comparable precision to the classical method of analysis. However, it is much simpler to apply and can be used despite the type of dynamical system and its dimensions. Moreover, the sample-based approach has some unique advantages and can be applied without the precise knowledge of parameter values.

  9. Ultrasonic Flaw Imaging via Multipath Exploitation

    Directory of Open Access Journals (Sweden)

    Yimin D. Zhang


    Full Text Available We consider ultrasonic imaging for the visualization of flaws in a material. Ultrasonic imaging is a powerful nondestructive testing (NDT tool which assesses material conditions via the detection, localization, and classification of flaws inside a structure. We utilize reflections of ultrasonic signals which occur when encountering different media and interior boundaries. These reflections can be cast as direct paths to the target corresponding to the virtual sensors appearing on the top and bottom side of the target. Some of these virtual sensors constitute a virtual aperture, whereas in others, the aperture changes with the transmitter position. Exploitations of multipath extended virtual array apertures provide enhanced imaging capability beyond the limitation of traditional multisensor approaches. The waveforms observed at the physical as well as the virtual sensors yield additional measurements corresponding to different aspect angles, thus allowing proper multiview imaging of flaws. We derive the wideband point spread functions for dominant multipaths and show that fusion of physical and virtual sensor data improves the flaw perimeter detection and localization performance. The effectiveness of the proposed multipath exploitation approach is demonstrated using real data.

  10. Linking soil chemistry, treeline shifts and climate change: scenario modeling using an experimental approach (United States)

    Mavris, Christian; Furrer, Gerhard; Anderson, Susanne; Blum, Alex; Wells, Aaron; Dahms, Dennis; Egli, Markus


    Climate change and global warming have a strong influence on the landscape development. As cold areas become warmer, both flora and fauna must adapt to new conditions (a). It is widely accepted that climate changes deeply influence the treeline shifts. In addition to that, wildfires, plant diseases and insect infestation (i.e. mountain pine beetle) can promote a selective replacement of plants, inhibiting some and favoring others, thus modifying the ecosystem in diverse ways. There is little knowledge on the behavior of soil chemistry when such changes occur. Will elemental availability become a crucial factor as a function of climate changes? The Sinks Canyon and Stough Basin - SE flank of the Wind River Range, Wyoming, USA - offer an ideal case study. Conceptually, the areas were divided into three main subsets: tundra, forest and a subarid environment. All soils were developed on granitoid moraines (b, c). From each subset, a liquid topsoil extract was produced and mixed with the solid subsoil samples in batch reactors at 50 °C. The batch experiments were carried out over 1800 h, and the progress of the dissolution was regularly monitored by analyzing liquid aliquots using IC and ICP-OES. The nutrients were mostly released within the first hours of the experiment. Silicon and Al were continuously released into the solution, while some alkali elements - i.e. Na - showed a more complex trend. Organic acids (acetic, citric) and other ligands produced during biodegradation played an active role in mineral dissolution and nutrient release. The mineral colloids detected in the extract (X-ray diffraction) can significantly control surface reactions (adsorption/desorption) and contributed to specific cationic concentrations. The experimental set up was then compared to a computed dissolution model using SerialSTEADYQL software (d, e). Decoding the mechanisms driving mineral weathering is the key to understand the main geochemical aspects of adaptation during climate

  11. Compressed sensing MRI exploiting complementary dual decomposition. (United States)

    Park, Suhyung; Park, Jaeseok


    Compressed sensing (CS) MRI exploits the sparsity of an image in a transform domain to reconstruct the image from incoherently under-sampled k-space data. However, it has been shown that CS suffers particularly from loss of low-contrast image features with increasing reduction factors. To retain image details in such degraded experimental conditions, in this work we introduce a novel CS reconstruction method exploiting feature-based complementary dual decomposition with joint estimation of local scale mixture (LSM) model and images. Images are decomposed into dual block sparse components: total variation for piecewise smooth parts and wavelets for residuals. The LSM model parameters of residuals in the wavelet domain are estimated and then employed as a regional constraint in spatially adaptive reconstruction of high frequency subbands to restore image details missing in piecewise smooth parts. Alternating minimization of the dual image components subject to data consistency is performed to extract image details from residuals and add them back to their complementary counterparts while the LSM model parameters and images are jointly estimated in a sequential fashion. Simulations and experiments demonstrate the superior performance of the proposed method in preserving low-contrast image features even at high reduction factors. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Comparing Different Approaches to Visualizing Light Waves: An Experimental Study on Teaching Wave Optics (United States)

    Mešic, Vanes; Hajder, Erna; Neumann, Knut; Erceg, Nataša


    Research has shown that students have tremendous difficulties developing a qualitative understanding of wave optics, at all educational levels. In this study, we investigate how three different approaches to visualizing light waves affect students' understanding of wave optics. In the first, the conventional, approach light waves are represented…

  13. Hydromechanical behavior of a quasi-saturated compacted soils on drying-wetting paths-experimental and numerical approaches

    Directory of Open Access Journals (Sweden)

    Andriantrehina Soanarivo Rinah


    Full Text Available This paper presents an experimental and numerical investigation funded by the French National Project “Terredurable”, which is devoted to the study of soils in quasi-saturated state. The experimental study is focused on the behavior of compacted soils on drying-wetting paths and the macroscopic effect of the drying path on shrinkage and cracking. Furthermore, a protocol for image analysis of crack in drying tests was developed. Two approaches are used for the measurement of surface strains and identification of the ultimate stress before the formation of the first crack, using VIC-2D software, and for the monitoring of crack evolution, using ImageJ software. The aim of the numerical approach is to reproduce the drying experiments with a finite difference code (FLAC 3D, in order to understand the stress conditions that can explain crack initiation, without modeling the crack formation itself.

  14. Opto-mechanical modelling and experimental approach to the measurement of aerospace materials using shearography and thermal loading (United States)

    Corso Krutul, Eduardo; Groves, Roger M.


    This paper is concerned with the modelling of the complete opto-mechanical measurement system, including shearography instrument, loading technique and the response of the object under test and the comparison of the simulation results with experimental results. To show the applicability of this technique, the response of an aluminium flat plate sample under thermal load was analysed. First a finite element model of the plate was generated, using an experimentally measured temperature profile. The strain and displacement values obtained from the finite element model were used to simulate the phase-map in the optical part of the model. The simulated phase maps were then compared qualitatively with experimental phase maps measured using shearography. This approach is suitable to understand the response of components under load and to predict anomalies such as defects, thereby making the analysis of measured phase maps easier and less empirical.

  15. Determination of acid dissociation constants (pKa) of cephalosporin antibiotics: Computational and experimental approaches. (United States)

    Ribeiro, Alyson R; Schmidt, Torsten C


    Cefapirin (CEPA) and ceftiofur (CEF) are two examples of widely used veterinarian cephalosporins presenting multiple ionization centers. However, the acid dissociation constants (pKa) of CEF are missing and experimental data about CEPA are rare. The same is true for many cephalosporins, where available data are either incomplete or even wrong. Environmentally relevant biotic and abiotic processes depend primordially on the antibiotic pH-dependent speciation. Consequently, this physicochemical parameter should be reliable, including the correct ionization center identification. In this direction, two experimental techniques, potentiometry and spectrophotometry, along with two well-known pKa predictors, Marvin and ACD/Percepta, were used to study the macro dissociation constants of CEPA and CEF. Additionally, the experimental dissociation constants of 14 cephalosporins available in the literature were revised, compiled and compared with data obtained in silico. Only one value was determined experimentally for CEF (2.68 ± 0.05), which was associated to the carboxylic acid group deprotonation. For CEPA two values were obtained experimentally: 2.74 ± 0.01 for the carboxylic acid deprotonation and 5.13 ± 0.01 for the pyridinium ring deprotonation. In general, experimentally obtained values agree with the in silico predicted data (ACD/Percepta RMSE: 0.552 and Marvin RMSE: 0.706, n = 88). However, for cephalosporins having imine and aminothiazole groups structurally close, Marvin presented problems in pKa predictions. For the biological and environmental fate and effect discussion, it is important to recognize that CEPA and CEF, as well as many other cephalosporins, are present as anionic species in the biologic and environmentally relevant pH values of 6-7.5. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. A Combined Numerical-Experimental Approach to Quantify the Thermal Contraction of A356 During Solidification (United States)

    Macht, J. P.; Maijer, D. M.; Phillion, A. B.


    A process for generating thermal contraction coefficients for use in the solidification modeling of aluminum castings is presented. Sequentially coupled thermal-stress modeling is used in conjunction with experimentation to empirically generate the thermal contraction coefficients for a strontium-modified A356 alloy. The impact of cooling curve analysis on the modeling procedure is studied. Model results are in good agreement with experimental findings, indicating a sound methodology for quantifying the thermal contraction. The technique can be applied to other commercially relevant aluminum alloys, increasing the utility of solidification modeling in the casting industry.

  17. Aphid Heritable Symbiont Exploits Defensive Mutualism. (United States)

    Doremus, Matthew R; Oliver, Kerry M


    Insects and other animals commonly form symbioses with heritable bacteria, which can exert large influences on host biology and ecology. The pea aphid, Acyrthosiphon pisum , is a model for studying effects of infection with heritable facultative symbionts (HFS), and each of its seven common HFS species has been reported to provide resistance to biotic or abiotic stresses. However, one common HFS, called X-type, rarely occurs as a single infection in field populations and instead typically superinfects individual aphids with Hamiltonella defensa , another HFS that protects aphids against attack by parasitic wasps. Using experimental aphid lines comprised of all possible infection combinations in a uniform aphid genotype, we investigated whether the most common strain of X-type provides any of the established benefits associated with aphid HFS as a single infection or superinfection with H. defensa We found that X-type does not confer protection to any tested threats, including parasitoid wasps, fungal pathogens, or thermal stress. Instead, component fitness assays identified large costs associated with X-type infection, costs which were ameliorated in superinfected aphids. Together these findings suggest that X-type exploits the aphid/ H. defensa mutualism and is maintained primarily as a superinfection by "hitchhiking" via the mutualistic benefits provided by another HFS. Exploitative symbionts potentially restrict the functions and distributions of mutualistic symbioses with effects that extend to other community members. IMPORTANCE Maternally transmitted bacterial symbionts are widespread and can have major impacts on the biology of arthropods, including insects of medical and agricultural importance. Given that host fitness and symbiont fitness are tightly linked, inherited symbionts can spread within host populations by providing beneficial services. Many insects, however, are frequently infected with multiple heritable symbiont species, providing potential

  18. The potential of antagonistic fungi for control of Fusarium graminearum and Fusarium crookwellense varies depending on the experimental approach. (United States)

    Schöneberg, A; Musa, T; Voegele, R T; Vogelgsang, S


    To investigate the potential of fungal antagonists to control Fusarium head blight (FHB) causing pathogens (Fusarium graminearum and F. crookwellense) with two different experimental approaches. Using two in vitro tests, Clonostachys rosea, Cladosporium cladosporioides and 10 Trichoderma strains were screened. In a co-culture assay, all Trichoderma strains significantly reduced the colony area of F. graminearum and F. crookwellense by 45-93%, whereas C. rosea and C. cladosporioides were not effective. In another assay, all antagonists from a chosen subset reduced the number of perithecia and ascospores on wheat straw by 88-100% when inoculated before the pathogen. Only C. rosea, a weak antagonist in the co-culture assay, was effective when inoculated after the pathogen, reducing perithecia and ascospore production by 73 and 100%, respectively. For screening antagonists and to avoid sorting out highly effective strains, it is crucial to consider different experimental approaches since the efficacy might differ substantially depending on the incubation conditions. By using two distinct experimental set-ups, we identified promising biological control agents. FHB is one of the most devastating fungal cereal diseases worldwide. As the pathogen overwinters on crop residues, application of antagonists on residues of the previous crop during harvest could be a promising approach to efficiently control FHB in cereals as an essential part of an integrated disease management. © 2015 The Society for Applied Microbiology.

  19. Automatic image exploitation system for small UAVs (United States)

    Heinze, N.; Esswein, M.; Krüger, W.; Saur, G.


    For surveillance and reconnaissance tasks small UAVs are of growing importance. These UAVs have an endurance of several hours, but a small payload of about some kilograms. As a consequence lightweight sensors and cameras have to be used without having a mechanical stabilized high precision sensor-platform, which would exceed the payload and cost limitations. An example of such a system is the German UAV Luna with optical and IR sensors on board. For such platforms we developed image exploitation algorithms. The algorithms comprise mosaiking, stabilization, image enhancement, video based moving target indication, and stereo-image generation. Other products are large geo-coded image mosaics, stereo mosaics, and 3-D-model generation. For test and assessment of these algorithms the experimental system ABUL has been developed, in which the algorithms are integrated. The ABUL system is used for tests and assessment by military PIs.

  20. Sensitivity-based approach to optimal experimental design in a receptor trafficking and down regulation model (United States)

    Casey, Fergal; Waterfall, Joshua; Gutenkunst, Ryan; Brown, Kevin; Myers, Christopher; Sethna, James


    We apply the ideas of optimal experimental design to systems biology models: minimizing a design criterion based on the average variance of predictions, we suggest new experiments that need to be performed to optimally test a given biological hypothesis. The estimated variance in predictions is derived from the sensitivities of protein and chemical species in the model to changes in reaction rates. The sensitivities also allow us to determine which interactions in the biological network dominate the system behavior. To test the design principles, we have developed a differential equation model incorporating the processes of endocytosis, recycling and degradation of activated epidermal growth factor (EGF) receptor in a mammalian cell line. Recent experimental work has discovered mutant proteins that cause receptor accumulation and a prolonged growth signal. Our model is optimized to fit this mutant experimental data and wild type data for a variety of experimental conditions. Of biological interest is the effect on surface and internalized receptor levels after the overexpression or inactivation of regulator proteins in the network: the optimal design method allows us to fine tune the conditions to best predict the behavior of these unknown components of the system.

  1. Computational and experimental approaches to the molecular structure of the HCl adduct of Me3PO. (United States)

    Orthaber, Andreas; Belaj, Ferdinand; Pietschnig, Rudolf


    The reaction of anhydrous HCl(g) with trimethyl phosphane oxide yields trimethylhydroxy phosphonium chloride. A crystal structure analysis showed that the prevalent mesomeric structure in the solid state is the phosphonium chloride ion pair. Ab initio calculations in the gas phase cannot reproduce these findings, whereas higher correlated methods (CISD) and solvation models predict the experimental structure correctly.

  2. A Transverse Oscillation Approach for Estimation of Three-Dimensional Velocity Vectors, Part II: Experimental Validation

    DEFF Research Database (Denmark)

    Pihl, Michael Johannes; Stuart, Matthias Bo; Tomov, Borislav Gueorguiev


    The 3-D transverse oscillation method is investigated by estimating 3-D velocities in an experimental flowrigsystem. Measurements of the synthesized transverse oscillatingfields are presented as well. The method employs a 2-D transducer; decouples the velocity estimation; and estimates the axial,...

  3. Costs and benefits of autonomy when learning a task: An experimental approach

    NARCIS (Netherlands)

    Wielenga-Meijer, E.G.A.; Taris, T.W.; Wigboldus, D.H.J.; Kompier, M.A.J.


    Previous findings suggested that the positive relationship between autonomy and learning outcomes (such as improved task performance) only holds up until a certain optimum level of autonomy has been reached. This assumption was investigated in an experimental study where 95 participants had to learn

  4. Experimental approach to validation of an analytical and numerical thermal analysis of a travelling wave tube (United States)

    Wiejak, W.; Wymysłowski, A.


    Travelling Wave Tube (TWT) is an electronic vacuum microwave device, which is used as a high power microwave amplifier, mainly in telecommunication purposes, e.g. radar systems. TWT's is an alternative solution in comparison to semiconductor devices in case of high power and high frequency applications. Thermal behaviour of TWT is one of the key aspects influencing its reliability and working parameters. The main goal of the research was to perform analytical, experimental and numerical analysis of a temperature distribution of a low band TWT in case of a typical working condition. Because the theoretical analysis seems to be very complex thus it was decided to compare the experimental results with the numerical simulations as well as with the simplified analytical formulas. As a first step of the presented research, the analytical analysis and numerical modelling of the helix TWT was carried out. The objective of the thermal analysis was to assess the temperature distribution in different parts of the helix TWT assembly during the extreme standard and working conditions. As a second stage of the research the numerical results were validated by the experimental measurements, which were carried out using a specially designed TWT test samples and corresponding experimental measurement tools.

  5. A Musical Approach to Reading Fluency: An Experimental Study in First-Grade Classrooms (United States)

    Leguizamon, Daniel F.


    The purpose of this quantitative, quasi-experimental study was to investigate the relationship between Kodaly-based music instruction and reading fluency in first-grade classrooms. Reading fluency and overall reading achievement were measured for 109 participants at mid-point in the academic year pre- and post treatment. Tests were carried out to…

  6. On the nature of preverbal focus in Greek : a theoretical and experimental approach

    NARCIS (Netherlands)

    Gryllia, Styliani (Stella)


    The relation between prosodic realization, syntactic structure, interpretation and focus has caused much debate in the literature. This thesis aims at contributing to our understanding of the semantic and prosodic properties of object foci in Greek, employing theoretical and experimental tools. The

  7. An engineering approach to business model experimentation – an online investment research startup case study

    NARCIS (Netherlands)

    Kijl, Björn; Boersma, Durk


    Every organization needs a viable business model. Strikingly, most of current literature is focused on business model design, whereas there is almost no attention for business model validation and implementation and related business model experimentation. The goal of the research as described in

  8. Neural Plasticity: Single Neuron Models for Discrimination and Generalization and an Experimental Ensemble Approach. (United States)


    this experimental framework. An outline of th. biology of the entorhinal cortex to dentate gyrus projection is therefore included at the end of Part IV...equilibria. For aq> aqa they are stable, otherwise they *repel" states. StLablit.L in uaia~ environments Isolated attractors are generally stable in

  9. Exploitation of subsea gas hydrate reservoirs (United States)

    Janicki, Georg; Schlüter, Stefan; Hennig, Torsten; Deerberg, Görge


    Natural gas hydrates are considered to be a potential energy resource in the future. They occur in permafrost areas as well as in subsea sediments and are stable at high pressure and low temperature conditions. According to estimations the amount of carbon bonded in natural gas hydrates worldwide is two times larger than in all known conventional fossil fuels. Besides technical challenges that have to be overcome climate and safety issues have to be considered before a commercial exploitation of such unconventional reservoirs. The potential of producing natural gas from subsea gas hydrate deposits by various means (e.g. depressurization and/or injection of carbon dioxide) is numerically studied in the frame of the German research project »SUGAR«. The basic mechanisms of gas hydrate formation/dissociation and heat and mass transport in porous media are considered and implemented into a numerical model. The physics of the process leads to strong non-linear couplings between hydraulic fluid flow, hydrate dissociation and formation, hydraulic properties of the sediment, partial pressures and seawater solution of components and the thermal budget of the system described by the heat equation. This paper is intended to provide an overview of the recent development regarding the production of natural gas from subsea gas hydrate reservoirs. It aims at giving a broad insight into natural gas hydrates and covering relevant aspects of the exploitation process. It is focused on the thermodynamic principles and technological approaches for the exploitation. The effects occurring during natural gas production within hydrate filled sediment layers are identified and discussed by means of numerical simulation results. The behaviour of relevant process parameters such as pressure, temperature and phase saturations is described and compared for different strategies. The simulations are complemented by calculations for different safety relevant problems.

  10. Final Report, “Exploiting Global View for Resilience”

    Energy Technology Data Exchange (ETDEWEB)

    Chien, Andrew [Univ. of Chicago, IL (United States)


    Final technical report for the "Exploiting Global View for Resilience" project. The GVR project aims to create a new approach to portable, resilient applications. The GVR approach builds on a global view data model,, adding versioning (multi-version), user control of timing and rate (multi-stream), and flexible cross layer error signalling and recovery. With a versioned array as a portable abstraction, GVR enables application programmers to exploit deep scientific and application code insights to manage resilience (and its overhead) in a flexible, portable fashion.

  11. Identification and induction of human, social, and cultural capitals through an experimental approach to stormwater management (United States)

    Decentralized stormwater management is based on the dispersal of stormwater management practices (SWMP) throughout a watershed to manage stormwater runoff volume and potentially restore natural hydrologic processes. This approach to stormwater management is increasingly popular b...

  12. An experimental approach to surgery of the equine fetlock and its associated structures. (United States)

    Meek, D G; Dickinson, E O


    An illustrated approach to the medial aspect of the equine fetlock joint is described, whereby the collateral ligaments are transected. This approach is suggested as a possible technique for metatarsal or metacarpal bone fracture repair by retrograde pinning, arthrodesis of the fetlock joint and other joint and sesamoid bone surgery. The histological evidence of satisfactory healing is presented and the advantages and disadvantages are discussed.

  13. A statistical approach to the experimental design of the sulfuric acid leaching of gold-copper ore

    Directory of Open Access Journals (Sweden)

    Mendes F.D.


    Full Text Available The high grade of copper in the Igarapé Bahia (Brazil gold-copper ore prevents the direct application of the classic cyanidation process. Copper oxides and sulfides react with cyanides in solution, causing a high consumption of leach reagent and thereby raising processing costs and decreasing recovery of gold. Studies have showm that a feasible route for this ore would be a pretreatment for copper minerals removal prior to the cyanidation stage. The goal of this experimental work was to study the experimental conditions required for copper removal from Igarapé Bahia gold-copper ore by sulfuric acid leaching by applying a statistical approach to the experimental design. By using the Plackett Burman method, it was possible to select the variables that had the largest influence on the percentage of copper extracted at the sulfuric acid leaching stage. These were temperature of leach solution, stirring speed, concentration of sulfuric acid in the leach solution and particle size of the ore. The influence of the individual effects of these variables and their interactions on the experimental response were analyzed by applying the replicated full factorial design method. Finally, the selected variables were optimized by the ascending path statistical method, which determined the best experimental conditions for leaching to achieve the highest percentage of copper extracted. Using the optimized conditions, the best leaching results showed a copper extraction of 75.5%.

  14. Intranasally administered oxytocin affects how dogs (Canis familiaris) react to the threatening approach of their owner and an unfamiliar experimenter. (United States)

    Hernádi, Anna; Kis, Anna; Kanizsár, Orsolya; Tóth, Katinka; Miklósi, Bernadett; Topál, József


    Fear and aggression are among the most prominent behavioural problems in dogs. Oxytocin has been shown to play a role in regulating social behaviours in humans including fear and aggression. As intranasal oxytocin has been found to have some analogous effects in dogs and humans, here we investigated the effect of oxytocin on dogs' behaviour in the Threatening Approach Test. Dogs, after having received intranasal administration of oxytocin (OT) or placebo (PL), showed the same reaction to an unfamiliar experimenter, but OT pretreated dogs showed a less friendly first reaction compared to the PL group when the owner was approaching. Individual differences in aggression (measured via questionnaire) also modulated dogs' first reaction. Moreover, subjects that received OT looked back more at the human (owner/experimenter) standing behind them during the threatening approach. These results suggest that oxytocin has an effect on dogs' response to the threatening cues of a human, but this effect is in interaction with other factors such as the identity of the approaching human and the 'baseline' aggression of the dogs. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. A New Two-Step Approach for Hands-On Teaching of Gene Technology: Effects on Students' Activities during Experimentation in an Outreach Gene Technology Lab (United States)

    Scharfenberg, Franz-Josef; Bogner, Franz X.


    Emphasis on improving higher level biology education continues. A new two-step approach to the experimental phases within an outreach gene technology lab, derived from cognitive load theory, is presented. We compared our approach using a quasi-experimental design with the conventional one-step mode. The difference consisted of additional focused…

  16. Impacts of radiation exposure on the experimental microbial ecosystem: a particle-based model simulation approach

    Energy Technology Data Exchange (ETDEWEB)

    Doi, M.; Tanaka, N.; Fuma, S.; Kawabata, Z.


    Well-designed experimental model ecosystem could be a simple reference of the actual environment and complex ecological systems. For ecological toxicity test of radiation and other environmental toxicants, we investigated and aquatic microbial ecosystem (closed microcosm) in the test tube with initial substrates,autotroph flagellate algae (Euglena, G.), heterotroph ciliate protozoa (Tetrahymena T.) and saprotroph bacteria (E, coli). These species organizes by itself to construct the ecological system, that keeps the sustainable population dynamics for more than 2 years after inoculation only by adding light diurnally and controlling temperature at 25 degree Celsius. Objective of the study is to develop the particle-based computer simulation by reviewing interactions among microbes and environment, and analyze the ecological toxicities of radiation on the microcosm by replicating experimental results in the computer simulation. (Author) 14 refs.

  17. Frequency response function of motors for switching noise energy with a new experimental approach

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyunsu [Ensemble Center for Automotive Research, Seoul (Korea, Republic of); Yoon, Jong-Yun [Incheon National University, Incheon (Korea, Republic of)


    Switching energy in electrical vehicles can create serious noise from the motors. However, the characteristics of switching noise in vehicle motors are not clear due to the complexity of measuring them. This study proposes a new experimental method to investigate the switching noise energy of a vehicle motor based on frequency response functions. A function generator-amplifier system is used to gen- erate the switching energy instead of the complex battery-inverter system that has previously been used to examine the noise energy characteristics. Even though newly adapted experimental method is simple, the switching noise energy was explicitly investigated under various input signals. Thus, this simple new method can be used to investigate the dynamic characteristics of noise energy in a vehicle motor.

  18. Exploring SiSn as a performance enhancing semiconductor: A theoretical and experimental approach

    KAUST Repository

    Hussain, Aftab M.


    We present a novel semiconducting alloy, silicon-tin (SiSn), as channel material for complementary metal oxide semiconductor (CMOS) circuit applications. The material has been studied theoretically using first principles analysis as well as experimentally by fabricating MOSFETs. Our study suggests that the alloy offers interesting possibilities in the realm of silicon band gap tuning. We have explored diffusion of tin (Sn) into the industry\\'s most widely used substrate, silicon (100), as it is the most cost effective, scalable and CMOS compatible way of obtaining SiSn. Our theoretical model predicts a higher mobility for p-channel SiSn MOSFETs, due to a lower effective mass of the holes, which has been experimentally validated using the fabricated MOSFETs. We report an increase of 13.6% in the average field effect hole mobility for SiSn devices compared to silicon control devices.

  19. Fatigue study on the actuation performance of macro fiber composite (MFC): theoretical and experimental approach (United States)

    Pandey, Akash; Arockiarajan, A.


    Macro fiber composite (MFC) is extensively used in vibration control and actuation applications due to its high flexibility and enhanced coupling coefficients. During these applications, MFCs are subjected to the continuous cyclic electrical loading, which may lead to the degradation in its actuation performance. In order to predict the life cycle of MFCs, an experimental setup has been devised and experiments are performed under cyclic loading condition. Efforts involved in the experiments are huge in terms of time and cost. Hence, an attempt has been made to develop a theoretical model to predict the fatigue behavior of MFCs. A nonlinear finite element method has been formulated based on Kirchhoff plate theory wherein the fatigue failure criterion based on strain energy is embedded. Simulated results based on the proposed model is compared with experimental observation and are in good agreement with each other. Variation in the life cycle of MFCs are also studied for different operating temperatures as well as structural/geometric configurations.

  20. A combined experimental with simulation approach to calibrated 3D strain measurement using shearography


    Goto, D.T.; Groves, R.M.


    This paper is concerned with the development of a calibrated 3D shearography strain measurement instrument, calibrated iteratively, using a combined mechanical-optical model and specially designed test objects. The test objects are a cylinder loaded by internal pressure and a flat plate under axial load. Finite element models of the samples, combined with optical models of the shearography system, allow phase maps to be simulated for subsequent comparison with experimental phase maps from the...

  1. An Experimental Approach to Determine the Flight Dynamics of NASA’s Mars Science Lab Capsule (United States)


    Transducer Module ( PTM ) packages and performed the free-flight experiments at ARL’s Transonic Experimental Facility at Aberdeen Proving Ground, MD...trajectory of the MSL capsule with instrumented MSL- PTM models, and recording flight data used for subsequent trajectory reconstruction. The method...tracking radar for lifting MSL-6 flight body. ...........................11 Figure 14. MSL- PTM CAD model assembly shown in exploded view

  2. Experimental studies of low salinity water flooding in carbonate reservoirs: A new promising approach

    DEFF Research Database (Denmark)

    Zahid, Adeel; Shapiro, Alexander; Skauge, Arne


    Low salinity water flooding is well studied for sandstone reservoirs, both laboratory and field tests have showed improvement in the oil recovery in many cases. Up to very recently, the low salinity effect has been indeterminated for carbonates. Most recently, Saudi Aramco reported that substanti...... of experimental results, discussions are made about possible mechanisms for improving oil recovery in carbonate reservoir as a function of change in brine salinity. Copyright 2012, Society of Petroleum Engineers....

  3. Experimental estimation of mutation rates in a wheat population with a gene genealogy approach. (United States)

    Raquin, Anne-Laure; Depaulis, Frantz; Lambert, Amaury; Galic, Nathalie; Brabant, Philippe; Goldringer, Isabelle


    Microsatellite markers are extensively used to evaluate genetic diversity in natural or experimental evolving populations. Their high degree of polymorphism reflects their high mutation rates. Estimates of the mutation rates are therefore necessary when characterizing diversity in populations. As a complement to the classical experimental designs, we propose to use experimental populations, where the initial state is entirely known and some intermediate states have been thoroughly surveyed, thus providing a short timescale estimation together with a large number of cumulated meioses. In this article, we derived four original gene genealogy-based methods to assess mutation rates with limited bias due to relevant model assumptions incorporating the initial state, the number of new alleles, and the genetic effective population size. We studied the evolution of genetic diversity at 21 microsatellite markers, after 15 generations in an experimental wheat population. Compared to the parents, 23 new alleles were found in generation 15 at 9 of the 21 loci studied. We provide evidence that they arose by mutation. Corresponding estimates of the mutation rates ranged from 0 to 4.97 x 10(-3) per generation (i.e., year). Sequences of several alleles revealed that length polymorphism was only due to variation in the core of the microsatellite. Among different microsatellite characteristics, both the motif repeat number and an independent estimation of the Nei diversity were correlated with the novel diversity. Despite a reduced genetic effective size, global diversity at microsatellite markers increased in this population, suggesting that microsatellite diversity should be used with caution as an indicator in biodiversity conservation issues.

  4. Experimental Approaches for Measuring pKa's in RNA and DNA (United States)

    Thaplyal, Pallavi; Bevilacqua, Philip C.


    RNA and DNA carry out diverse functions in biology including catalysis, splicing, gene regulation, and storage of genetic information. Interest has grown in understanding how nucleic acids perform such sophisticated functions given their limited molecular repertoire. RNA can fold into diverse shapes that often perturb pKa values and allow it to ionize appreciably under biological conditions, thereby extending its molecular diversity. The goal of this article is to enable experimental measurement of pKa's in RNA and DNA. A number of experimental methods for measuring pKa values in RNA and DNA have been developed over the last ten years, including RNA cleavage kinetics; UV-, fluorescence-, and NMR-detected pH titrations; and Raman crystallography. We begin with general considerations for choosing a pKa assay and then describe experimental conditions, advantages and disadvantages for these methods. Potential pitfalls in measuring a pKa are provided including the presence of apparent pKa's due to a kinetic pKa or coupled acid- and alkali-promoted RNA unfolding, as well as RNA degradation, precipitation of metal hydroxides and poor baselines. Use of multiple data fitting procedures and the study of appropriate mutants are described as ways to avoid some of these pitfalls. Application of these experimental methods to RNA and DNA will increase the number of nucleic acid pKa values in the literature, which should deepen insight into biology and provide benchmarks for calculations. Future directions for measuring pKa's in nucleic acids are discussed. PMID:25432750

  5. Microbial Experimental Evolution as a Novel Research Approach in the Vibrionaceae and Squid-Vibrio Symbiosis

    Directory of Open Access Journals (Sweden)

    William eSoto


    Full Text Available The Vibrionaceae are a genetically and metabolically diverse family living in aquatic habitats with a great propensity toward developing interactions with eukaryotic microbial and multicellular hosts (as either commensals, pathogens, and mutualists. The Vibrionaceae frequently possess a life history cycle where bacteria are attached to a host in one phase and then another where they are free from their host as either part of the bacterioplankton or adhered to a solid substrate such as marine sediment, riverbeds, lakebeds, or floating particulate debris. These two stages in their life history exert quite distinct and separate selection pressures. When bound to solid substrates or to host cells, the Vibrionaceae can also exist as complex biofilms. The association between bioluminescent Vibrio spp. and sepiolid squids (Cephalopoda: Sepiolidae is an experimentally tractable model to study bacteria and animal host interactions, since the symbionts and squid hosts can be maintained in the laboratory independently of one another. The bacteria can be grown in pure culture and the squid hosts raised gnotobiotically with sterile light organs. The partnership between free-living Vibrio symbionts and axenic squid hatchlings emerging from eggs must be renewed every generation of the cephalopod host. Thus, symbiotic bacteria and animal host can each be studied alone and together in union. Despite virtues provided by the Vibrionaceae and sepiolid squid-Vibrio symbiosis, these assets to evolutionary biology have yet to be fully utilized for microbial experimental evolution. Experimental evolution studies already completed are reviewed, along with exploratory topics for future study.

  6. Validation of experimental medicine methods in psychiatry: the P1vital approach and experience. (United States)

    Dawson, Gerard R; Craig, Kevin J; Dourish, Colin T


    In the pharmaceutical industry deciding whether to progress a compound to the next stage of development or choosing between compounds in a development portfolio is laden with risk. This is particularly true of compounds developed to treat CNS disorders. The use of pre-clinical models in CNS drug development is well established but these models often lack predictive validity and many compounds fail when they reach the target patient group. Bridging the gap between pre-clinical CNS models and patient studies, P1vital's objective is to develop human volunteer models that will enable rapid, accurate and reliable decision making about which compounds to progress into patient trials. The research strategy of P1vital and its academic research network is to focus on science that progresses the development of clinical efficacy models. As part of this strategy P1vital established a CNS Experimental Medicine Consortium with members from both academic research and the pharmaceutical industry. This consortium is unique in that experimental medicine models initially developed through academic research are selected for further validation in a process that is managed by the Pharma members of the P1vital CNS Experimental Medicine Consortium steering (PEM) committee. The P1vital consortium is very much a work in progress. However, since its inception in 2007 the consortium has successfully delivered results from five clinical studies in four therapeutic areas namely, anxiety, cognitive disorders, schizophrenia and depression. 2011. Published by Elsevier Inc.

  7. The effects of paternal disengagement on women's sexual decision making: an experimental approach. (United States)

    Delpriore, Danielle J; Hill, Sarah E


    An abundance of research demonstrates a robust association between father absence--or low-quality paternal involvement--and daughters' accelerated sexual development, promiscuity, and sexual risk taking. Although recent natural experiments provide support for fathers playing a causal role in these outcomes, these effects have not been examined using a randomized experimental design to eliminate genetic and environmental confounds inherent in previous studies. We redressed this empirical gap by experimentally testing the effects of primed paternal disengagement cues on women's sexual decision making. Across 5 experiments, reminders of paternal disengagement increased women's activation of sexual thoughts (Experiment 1), sexual permissiveness (Experiments 2-4), and negativity toward condom use (Experiment 5). Moreover, these effects were specific to women's sexual decision making, as paternal disengagement cues failed to influence women's willingness to take nonsexual risks (Experiment 4) or men's risky sexual attitudes (Experiment 5). These results provide the first true experimental evidence supporting a causal relationship between paternal disengagement and changes in women's psychology that promote risky sexual behavior.

  8. Microbial experimental evolution as a novel research approach in the Vibrionaceae and squid-Vibrio symbiosis (United States)

    Soto, William; Nishiguchi, Michele K.


    The Vibrionaceae are a genetically and metabolically diverse family living in aquatic habitats with a great propensity toward developing interactions with eukaryotic microbial and multicellular hosts (as either commensals, pathogens, and mutualists). The Vibrionaceae frequently possess a life history cycle where bacteria are attached to a host in one phase and then another where they are free from their host as either part of the bacterioplankton or adhered to solid substrates such as marine sediment, riverbeds, lakebeds, or floating particulate debris. These two stages in their life history exert quite distinct and separate selection pressures. When bound to solid substrates or to host cells, the Vibrionaceae can also exist as complex biofilms. The association between bioluminescent Vibrio spp. and sepiolid squids (Cephalopoda: Sepiolidae) is an experimentally tractable model to study bacteria and animal host interactions, since the symbionts and squid hosts can be maintained in the laboratory independently of one another. The bacteria can be grown in pure culture and the squid hosts raised gnotobiotically with sterile light organs. The partnership between free-living Vibrio symbionts and axenic squid hatchlings emerging from eggs must be renewed every generation of the cephalopod host. Thus, symbiotic bacteria and animal host can each be studied alone and together in union. Despite virtues provided by the Vibrionaceae and sepiolid squid-Vibrio symbiosis, these assets to evolutionary biology have yet to be fully utilized for microbial experimental evolution. Experimental evolution studies already completed are reviewed, along with exploratory topics for future study. PMID:25538686

  9. Evaluating Approaches to Teaching and Learning Chinese Vocabulary from the Learning Theories Perspective: An Experimental Case Study

    Directory of Open Access Journals (Sweden)

    Katja SIMONČIČ


    Full Text Available With Chinese language gaining more and more popularity among Slovenian students and with the growing numbers of learners of Chinese as a foreign language in Slovenia and elsewhere it is crucial to find an approach that will lead to high quality and long-term knowledge of Chinese and that will motivate learners to continue learning. We can speak of two basic approaches to teaching Chinese vocabulary: the approach that first introduces pronunciation and the approach that simultaneously introduces pronunciation and character. The key question that arises is which of the two approaches leads to high quality and long-term knowledge? To answer the question an experimental case study was carried out at Ljubljana’s Faculty of Arts in the academic year 2011/2012. The case study showed that the approach that simultaneously introduces pronunciation and character and is based on the key principles of constructivist learning theory had beneficial effects on the students in terms of motivation and quality of knowledge of Chinese vocabulary.

  10. Amphibole reaction rims as a record of pre-eruptive magmatic heating: An experimental approach (United States)

    De Angelis, S. H.; Larsen, J.; Coombs, Michelle L.; Dunn, A.; Hayden, Leslie A.


    Magmatic minerals record the pre-eruptive timescales of magma ascent and mixing in crustal reservoirs and conduits. Investigations of the mineral records of magmatic processes are fundamental to our understanding of what controls eruption style, as ascent rates and magma mixing processes are well known to control and/or trigger potentially hazardous explosive eruptions. Thus, amphibole reaction rims are often used to infer pre-eruptive magma dynamics, and in particular to estimate magma ascent rates. However, while several experimental studies have investigated amphibole destabilization during decompression, only two investigated thermal destabilization relevant to magma mixing processes. This study examines amphibole decomposition experimentally through isobaric heating of magnesio-hornblende phenocrysts within a natural high-silica andesite glass. The experiments first equilibrated for 24 h at 870 °C and 140 MPa at H2O-saturated conditions and ƒO2 ∼ Re–ReO prior to rapid heating to 880, 900, or 920 °C and hold times of 3–48 h. At 920 °C, rim thicknesses increased from 17 μm after 3 h, to 55 μm after 12 h, and became pseudomorphs after longer durations. At 900 °C, rim thicknesses increased from 7 μm after 3 h, to 80 μm after 24 h, to pseudomorphs after longer durations. At 880 °C, rim thicknesses increased from 7 μm after 3 h, to 18 μm after 36 h, to pseudomorphs after 48 h. Reaction rim microlites vary from 5–16 μm in size, with no systematic relationship between crystal size and the duration or magnitude of heating. Time-averaged rim microlite growth rates decrease steadily with increasing experimental duration (from  to 3.1 to ). Time-averaged microlite nucleation rates also decrease with increasing experimental duration (from  to 5.3 mm−3 s−1). There is no systematic relationship between time-averaged growth or nucleation rates and the magnitude of the heating step. Ortho- and clinopyroxene together constitute 57–90

  11. Experimental support for an immunological approach to the search for life on other planets. (United States)

    Schweitzer, Mary Higby; Wittmeyer, Jennifer; Avci, Recep; Pincus, Seth


    We propose a three-phase approach to test for evidence of life in extraterrestrial samples. The approach capitalizes on the flexibility, sensitivity, and specificity of antibody-antigen interactions. Data are presented to support the first phase, in which various extraction protocols are compared for efficiency, and in which a preliminary suite of antibodies are tested against various antigens. The antigens and antibodies were chosen on the basis of criteria designed to optimize the detection of extraterrestrial biomarkers unique to living or once-living organisms.

  12. New insight in the role of modifying ligands in the sol-gel processing of metal alkoxide precursors: a possibility to approach new classes of materials

    NARCIS (Netherlands)

    Kessler, Vadim G.; Spijksma, G.I.; Seisenbaeva, Gulaim A.; Hakansson, Sebastian; Hakansson, O.H.; Blank, David H.A.; Bouwmeester, Henricus J.M.


    This paper summarizes recent literature data and presents new experimental data on the mechanisms of chemical modification, hydrolysis and polycondensation of the alkoxides and demonstrates possibilities to approach new classes of materials, exploiting these mechanisms. Low reactivity of silicon


    African Journals Online (AJOL)


    The sexual exploitation of children by peacekeepers is particularly insidious. Educational interventions and training initiatives to bring about behaviour change to address sexual exploitation and abuse .... its own peacekeeping personnel are engaging in acts of sexual exploitation and abuse, including such crimes as rape.

  14. The exploitation argument against commercial surrogacy. (United States)

    Wilkinson, Stephen


    This paper discusses the exploitation argument against commercial surrogacy: the claim that commercial surrogacy is morally objectionable because it is exploitative. The following questions are addressed. First, what exactly does the exploitation argument amount to? Second, is commercial surrogacy in fact exploitative? Third, if it were exploitative, would this provide a sufficient reason to prohibit (or otherwise legislatively discourage) it? The focus throughout is on the exploitation of paid surrogates, although it is noted that other parties (e.g. 'commissioning parents') may also be the victims of exploitation. It is argued that there are good reasons for believing that commercial surrogacy is often exploitative. However, even if we accept this, the exploitation argument for prohibiting (or otherwise legislatively discouraging) commercial surrogacy remains quite weak. One reason for this is that prohibition may well 'backfire' and lead to potential surrogates having to do other things that are more exploitative and/or more harmful than paid surrogacy. It is concluded therefore that those who oppose exploitation should (rather than attempting to stop particular practices like commercial surrogacy) concentrate on: (a) improving the conditions under which paid surrogates 'work'; and (b) changing the background conditions (in particular, the unequal distribution of power and wealth) which generate exploitative relationships.

  15. Holistic Experimentation for Emergence: A Creative Approach to Postgraduate Entrepreneurship Education and Training (United States)

    Mitra, Jay


    This article explores the development of a comprehensive and systemic approach to entrepreneurship education at a research-intensive university in the United Kingdom. The exploration is based on two key conceptual challenges: (a) taking entrepreneurship to mean something more than new business creation and (b) differentiating between…

  16. Experimental validation of the Higher-Order Theory approach for sandwich panels with flexible core materials

    NARCIS (Netherlands)

    Straalen, IJ.J. van


    During tthe 1990's the higher-order theory was developed by Frostig to enable detailed stress analyses of sandwich panel structures. To investigate the potentials of this approach experiments are performed on sandwich panels made of thin steel faces and mineral wool or polystyrene core material. A

  17. Deltalink, Socio-Technical Development in the Delta : An Experimental Approach to Water Related Needs

    NARCIS (Netherlands)

    Rammelt, C.; Alibux, F.; Sutjahjo, D.; Wong Yee Kwan, S.


    Bangladesh is one of the poorest and densely populated deltas in the world. Due to institutional and financial limitations of the central government as well as past failures of the conventional top-down approach we suggest bottom-up strategies to increase the communities' ability to manage their own

  18. An in silico approach helped to identify the best experimental design, population, and outcome for future randomized clinical trials. (United States)

    Bajard, Agathe; Chabaud, Sylvie; Cornu, Catherine; Castellan, Anne-Charlotte; Malik, Salma; Kurbatova, Polina; Volpert, Vitaly; Eymard, Nathalie; Kassai, Behrouz; Nony, Patrice


    The main objective of our work was to compare different randomized clinical trial (RCT) experimental designs in terms of power, accuracy of the estimation of treatment effect, and number of patients receiving active treatment using in silico simulations. A virtual population of patients was simulated and randomized in potential clinical trials. Treatment effect was modeled using a dose-effect relation for quantitative or qualitative outcomes. Different experimental designs were considered, and performances between designs were compared. One thousand clinical trials were simulated for each design based on an example of modeled disease. According to simulation results, the number of patients needed to reach 80% power was 50 for crossover, 60 for parallel or randomized withdrawal, 65 for drop the loser (DL), and 70 for early escape or play the winner (PW). For a given sample size, each design had its own advantage: low duration (parallel, early escape), high statistical power and precision (crossover), and higher number of patients receiving the active treatment (PW and DL). Our approach can help to identify the best experimental design, population, and outcome for future RCTs. This may be particularly useful for drug development in rare diseases, theragnostic approaches, or personalized medicine. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Experimental Approaches to Understanding Surficial Processes on Mars: The Stony Brook Experience 2000-2016 (United States)

    McLennan, S. M.; Dehouck, E.; Hurowitz, J.; Lindsley, D. H.; Schoonen, M. A.; Tosca, N. J.; Zhao, Y. Y. S.


    Starting with Pathfinder and Global Surveyor, recent missions to Mars have provided great opportunity for low-temperature experimental geochemistry investigations of the Martian sedimentary record by providing geochemical and mineralogical data that can be used as meaningful tests for experiments. These missions have documented a long-lived, complex and dynamic sedimentary rock cycle, including "source-to-sink" sedimentary systems and global paleoenvironmental transitions through time. We designed and constructed an experimental facility, beginning in 2000, specifically to evaluate surficial processes on Mars. Our experimental philosophy has been to (1) keep apparatus simple and flexible, and if feasible maintain sample access during experiments; (2) use starting materials (minerals, rocks) close to known Mars compositions (often requiring synthesis); (3) address sedimentary processes supported by geological investigations at Mars; (4) begin with experiments at standard conditions so they are best supported by thermodynamics; (5) support experiments with thermodynamic-kinetic-mass balance modeling in both design and interpretation, and by high quality chemical, mineralogical and textural lab analyses; (6) interpret results in the context of measurements made at Mars. Although eliciting much comment in proposal and manuscript reviews, we have not attempted to slavishly maintain "Mars conditions", doing so only to the degree required by variables being tested in any given experiments. Among the problems we have addressed are (1) Amazonian alteration of rock surfaces; (2) Noachian-Hesperian chemical weathering; (3) epithermal alteration of `evolved' igneous rocks; (4) mineral surface chemical reactivity from aeolian abrasion; (5) evaporation of mafic brines; (6) early diagenesis of sedimentary iron mineralogy; (7) trace element and halogen behavior during chemical weathering and diagenesis; (8) photochemical influences on halogen distribution and speciation; (9) post

  20. The Teaching of Enzymes: A Low Cost Experimental Approach with High School Students.

    Directory of Open Access Journals (Sweden)



    Full Text Available The association of experimental methods with the traditional lecturing of Science themes is encouraged by several authors. The importance ofconducting experimental classes is undeniable, as practical activities motivate students to search for kno wledge. But this is not the reality in most publicschools in the inlands of Rio de Janeiro’s State, where several factors prevent teachers from using such didactic strategy.   The aim of this  work  was demonstrate  low -cost experimental activities, addressing the subject enzymes. The practice has been designed for being held in a common classroom. Lab glassware was replaced by alternative materials. Potato extract  (catalase source and commercial hydrogen peroxide were required. Concepts such as kinetic data  related to substrate concentration, time of reaction, pH andtemperature effects on enzymatic activity have been  explored with the students. Graphical representation of enzyme activity related to the above parameters has also been elaborated. The practice w as held in 10 schools distributed among 7 different cities. Questionnaires have been applied to the students before and after the practice and revealed that 86% of the students had never participated of a practical lesson and 49% were unaware of the functi on of enzymes. After practice, 68% of the students said that the enzymes catalyze biological reactions and 73% considered the practice important to their cognitive achievement. The evaluation of information obtained from students confirmed the lack of practical activities in public education, as well as the capacity that the practical activities have  to motivate the students in the knowledge formation process.

  1. Predicting experimental properties of integral membrane proteins by a naive Bayes approach. (United States)

    Martin-Galiano, Antonio J; Smialowski, Pawel; Frishman, Dmitrij


    Integral membrane proteins (iMPs) are challenging targets for structure determination because of the substantial experimental difficulties involved in their sample preparation. Accordingly, success rates of large-scale structural genomics consortia are much lower for this class of molecules compared to globular targets, underscoring the pressing need for predictive strategies to identify iMPs that are more likely to overcome laboratory bottlenecks. On the basis of the target status information available in the TargetDB repository, we describe the first large-scale analysis of experimental behavior of iMPs. Using information on recalcitrant and propagating iMP targets as negative and positive sets, respectively, we present naive Bayes classifiers capable of predicting, from sequence alone, those proteins that are more amenable to cloning, expression, and solubilization studies. Protein sequences are represented in the space of 72 features, including amino acid composition, occurrence of amino acid groups, ratios between residue groups, and hydrophobicity measures. Taking into account unequal representation of main taxonomic groups in the TargetDB, sequence database had a beneficial effect on the prediction results. The classifiers achieve accuracies of 70%, 63-70%, and 61% in predicting the amenability of iMPs for cloning, expression, and solubilization, respectively, thus making them useful tools in target selection for structure determination. Our assessment of prediction results clearly demonstrates that classifiers based on single features do not possess acceptable discriminative power and that the experimental behavior of iMPs is imprinted in their primary sequence through relationships between a restricted set of key properties. In most cases, sets of 10-20 protein features were found actually relevant, most notably, the content of isoleucine, valine, and positively-charged residues. 2007 Wiley-Liss, Inc.

  2. An Experimental Investigation of Computer Program Development Approaches and Computer Programming Metrics. (United States)


    Approved for plbi elaSO; 81 1ibutio u0lim t 03 /1 Technical Report TR-853 December 1979 An Experimental Investigation of Computer Program Development...this Report) Approved for public release; distribution unlimited. 17. DISTRIBUTION STATEMENT (of rhe entled i f [31-k 20, ! dil(enot fo, ).R...55t -3 O 2 a. tL loco o.uaZ 4 1 0 0 - .. a .CO acca 4 * ao -- c- - .an za-e~a- 2.5 aa34z98ba a- CHAPTER VII coipletely differentiated outcome is

  3. A systematic multiscale modeling and experimental approach to protect grain boundaries in magnesium alloys from corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Horstemeyer, Mark R. [Mississippi State Univ., Mississippi State, MS (United States); Chaudhuri, Santanu [Univ. of Illinois, Urbana-Champaign, IL (United States)


    A multiscale modeling Internal State Variable (ISV) constitutive model was developed that captures the fundamental structure-property relationships. The macroscale ISV model used lower length scale simulations (Butler-Volmer and Electronics Structures results) in order to inform the ISVs at the macroscale. The chemomechanical ISV model was calibrated and validated from experiments with magnesium (Mg) alloys that were investigated under corrosive environments coupled with experimental electrochemical studies. Because the ISV chemomechanical model is physically based, it can be used for other material systems to predict corrosion behavior. As such, others can use the chemomechanical model for analyzing corrosion effects on their designs.

  4. Optical waveguiding and applied photonics technological aspects, experimental issue approaches and measurements

    CERN Document Server

    Massaro, Alessandro


    Optoelectronics--technology based on applications light such as micro/nano quantum electronics, photonic devices, laser for measurements and detection--has become an important field of research. Many applications and physical problems concerning optoelectronics are analyzed in Optical Waveguiding and Applied Photonics.The book is organized in order to explain how to implement innovative sensors starting from basic physical principles. Applications such as cavity resonance, filtering, tactile sensors, robotic sensor, oil spill detection, small antennas and experimental setups using lasers are a

  5. Characterization of Sound Transmission Loss of Laminated Glass with Analytical and Experimental Approaches

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xin; Simmons, Kevin L.; Khaleel, Mohammad A.


    In this project, we have developed the general formation for calculating transmission loss of sound waves through multi-layered structures. Full factorial design method has also been used to investigate the relative effect of various geometric and material parameters on the transmission loss. It was found that within the range of practical interest, the most effect way of increasing transmission loss is by increasing either the glass thickness or increasing the inner layer mass density. Experimental measurements of sound transmission loss (in decibels) for four laminated glass samples have been made in accordance to SAE J1400, in third-octave bands between 125 Hz and 8 kHz.

  6. N2C2M2 Experimentation and Validation: Understanding Its C2 Approaches and Implications (United States)


    the organization and execution of the experiments, specifically, Col. Fernando Freire , LtCol. António Flambó, LtCol. José Martins, LtCol. Paulo ...of ELICIT Experimental Data. Paper presented at the 13th ICCRTS, Seattle, USA, 2008. [13.] Manso, Marco, and Paulo Nunes. ELICIT and the Future C2...detailed mapping between C2 CRM variables and ELICIT refer to: MANSO, Marco, and Paulo NUNES. ELICIT and the Future C2: Theoretical Foundations for the

  7. Intertemporal Choice of Marine Ecosystem Exploitation

    DEFF Research Database (Denmark)

    Ravn-Jonsen, Lars

    Management, however, requires models that can link the ecosystem level to the operation level, so this paper examines an ecosystem production model and shows that it is suitable for applying ground rent theory. This model is the simplest possible that incorporates the principles of size as the main...... at the ecosystem level in the present management. Therefore, economic predictions for an ecosystem managed as a common pool resource must be that  the exploitation probably are conducted at lower sized than optimum. In addition, given its population stock approach, the present management probably overlooks...... the ability of an ecosystem to sustain total volume of harvest. Given the two aspects of intertemporal choice revealed by the model, the conclusion must be that the Fishing Down Marine Food Webs is probably driven by the current management's inability to conduct adequate intertemporal balancing; therefore...

  8. Behaviour-dependent Predation Risk in Marine Planktonic Copepods: an Experimental and Modelling Approach (United States)

    Almeda, R.; van Someren Gréve, H.; Kiørboe, T.


    Zooplankton exhibit different motile behaviors related to mating, feeding and swimming activities. These differences in motility may imply different levels of predation risk, which may partially determine the structure of pelagic communities. However, empirical evidence and models of the influence of zooplankton behavior on predation risk are still limited. In this study, we experimentally investigated predation mortality related to different motile behaviors in marine planktonic copepods. We conducted bottle incubation predation experiments to estimate predation risk associated with (i) mating- and gender differences in behavior and (ii) feeding/ swimming activity (ambush feeders vs feeding-current vs. cruising feeders). Low and high speed video-filming was used to determine prey motility behavior parameters such as speeds, durations and frequencies of sinking, swimming and jumping events, as well as escape responses of each prey type. We will present experimental results of predation on copepod with different motile behavior and propose a simple prey behavior-dependent encounter model to predict predation risk on planktonic copepods. Overall, our results demonstrate that motile behavior is a key factor affecting predation risk in zooplankton.

  9. Application of Lean-Six Sigma Approach in a Laboratory Experimental Case Study

    Directory of Open Access Journals (Sweden)

    Hashim Raza Rizvi


    Full Text Available Laboratory experiments are a conventional activity performed at academic institutions, government and private organizations. These experimental studies provide the basis for new inventions in the field of science and engineering. Laboratory experiments are conducted on the basis of provided guidelines, already established by different standard organizations like ASTM, AASHTO etc. This article is based on a case study in which the process of an experiment is examined on the basis of Value Stream Maps (VSM and potential improvement possibilities have been identified. After determining the potential waste, appropriate Lean tools are selected to implement and observe the improvements. The process is examined after application of the Lean tools and a comparison is performed. University laboratory environment can be improved considerably by applying Lean Tools. MUDA application reduced the total work time from 90.75 hours and 10-CD to 63.75 hours and 7-CD hence saving, 27 hours and 3-CD for one experiment. This is remarkable achievement of this application. Heijunka application provided the students equal workload and they performed explicitly better than they used to. 5-S tool provided the students the opportunity to manage the laboratory in an effective and clean way. Safety of the students is a very major concern at university laboratory environment. 5-S not only upgraded the laboratory overall performance, but it significantly raised the safety standards of the laboratory. More application of the Lean Tools should be exercised explored to have more effective and efficient university laboratory experimental environment.

  10. Low pressure premixed CH4/air flames with forced periodic mixture fraction oscillations: experimental approach (United States)

    Ax, H.; Kutne, P.; Meier, W.; König, K.; Maas, U.; Class, A.; Aigner, M.


    An experimental setup for the generation and investigation of periodic equivalence ratio oscillations in laminar premixed flames is presented. A special low-pressure burner was developed which generates stable flames in a wide pressure range down to 20 mbar and provides the possibility of rapid mixture fraction variations. The technical realization of the mixture fraction variations and the characteristics of the burner are described. 1D laser Raman scattering was applied to determine the temperature and concentration profiles of the major species through the flame front in correlation to the phase-angle of the periodic oscillation. OH* chemiluminescence was detected to qualitatively analyze the response of the flame to mixture fraction variations by changing shape and position. Exemplary results from a flame at p=69 mbar, forced at a frequency of 10 Hz, are shown and discussed. The experiments are part of a cooperative research project including the development of kinetic models and numerical simulation tools with the aim of a better understanding and prediction of periodic combustion instabilities in gas turbines. The focus of the current paper lies on the presentation of the experimental realization and the measuring techniques.

  11. Testing Local Adaptation in a Natural Great Tit-Malaria System: An Experimental Approach.

    Directory of Open Access Journals (Sweden)

    Tania Jenkins

    Full Text Available Finding out whether Plasmodium spp. are coevolving with their vertebrate hosts is of both theoretical and applied interest and can influence our understanding of the effects and dynamics of malaria infection. In this study, we tested for local adaptation as a signature of coevolution between malaria blood parasites, Plasmodium spp. and its host, the great tit, Parus major. We conducted a reciprocal transplant experiment of birds in the field, where we exposed birds from two populations to Plasmodium parasites. This experimental set-up also provided a unique opportunity to study the natural history of malaria infection in the wild and to assess the effects of primary malaria infection on juvenile birds. We present three main findings: i there was no support for local adaptation; ii there was a male-biased infection rate; iii infection occurred towards the end of the summer and differed between sites. There were also site-specific effects of malaria infection on the hosts. Taken together, we present one of the few experimental studies of parasite-host local adaptation in a natural malaria system, and our results shed light on the effects of avian malaria infection in the wild.

  12. Biocompatible Nanoemulsions for Improved Aceclofenac Skin Delivery: Formulation Approach Using Combined Mixture-Process Experimental Design. (United States)

    Isailović, Tanja; Ðorđević, Sanela; Marković, Bojan; Ranđelović, Danijela; Cekić, Nebojša; Lukić, Milica; Pantelić, Ivana; Daniels, Rolf; Savić, Snežana


    We aimed to develop lecithin-based nanoemulsions intended for effective aceclofenac (ACF) skin delivery utilizing sucrose esters [sucrose palmitate (SP) and sucrose stearate (SS)] as additional stabilizers and penetration enhancers. To find the suitable surfactant mixtures and levels of process variables (homogenization pressure and number of cycles - high pressure homogenization manufacturing method) that result in drug-loaded nanoemulsions with minimal droplet size and narrow size distribution, a combined mixture-process experimental design was employed. Based on optimization data, selected nanoemulsions were evaluated regarding morphology, surface charge, drug-excipient interactions, physical stability, and in vivo skin performances (skin penetration and irritation potential). The predicted physicochemical properties and storage stability were proved satisfying for ACF-loaded nanoemulsions containing 2% of SP in the blend with 0%-1% of SS and 1%-2% of egg lecithin (produced at 50°C/20 cycles/800 bar). Additionally, the in vivo tape stripping demonstrated superior ACF skin absorption from these nanoemulsions, particularly from those containing 2% of SP, 0.5% of SS, and 1.5% of egg lecithin, when comparing with the sample costabilized by conventional surfactant - polysorbate 80. In summary, the combined mixture-process experimental design was shown as a feasible tool for formulation development of multisurfactant-based nanosized delivery systems with potentially improved overall product performances.

  13. Food availability and offspring sex in a monogamous seabird: insights from an experimental approach (United States)

    Merkling, Thomas; Leclaire, Sarah; Danchin, Etienne; Lhuillier, Emeline; Wagner, Richard H.; White, Joël; Hatch, Scott A.; Blanchard, Pierrick


    Sex allocation theory predicts that parents should favor offspring of the sex that provides the greatest fitness return. Despite growing evidence suggesting that vertebrates are able to overcome the constraint of chromosomal sex determination, the general pattern remains equivocal, indicating a need for experimental investigations. We used an experimental feeding design to study sex allocation during 3 years in black-legged kittiwakes (Rissa tridactyla). Intense male–male competition for securing a breeding site is common in this species in which males are heavier and larger than females. Hence, we hypothesized that parents producing fledglings in better than average condition, as supplementarily fed pairs do, would increase their fitness return by producing sons. Conversely, producing daughters would be a better tactic for Unfed parents. Hence, we predicted that Fed parents produce more sons than Unfed parents. This prediction is particularly expected if sexual dimorphism arises as early as during chick rearing, suggesting strong selective pressures for optimal male development. Our results showed that 1) males were heavier and larger than females prior to fledging and that 2) Fed parents produced relatively more male hatchlings than Unfed parents. We interpret this result in terms of a Trivers–Willard-type process. Furthermore, our data revealed that Unfed parents significantly overproduced female hatchlings, whereas offspring sex ratio was balanced among Fed parents. Because the 3 reproductive seasons we considered were particularly poor food years, Unfed parents may have overproduced daughters to avoid the apparent higher reproductive costs of raising sons.

  14. Opening the Implicit Leadership Theories’ Black Box: An Experimental Approach with Conjoint Analysis

    Directory of Open Access Journals (Sweden)

    Gustavo M. Tavares


    Full Text Available Although research on implicit leadership theories (ILTs has concentrated on determining which attributes define a leadership prototype, little attention has been paid to testing the relative importance of each of these attributes for individuals’ leadership perceptions. Building on socio-cognitive theories of impression processes, we experimentally explore the formation of leadership perceptions based on the recognition of six key attributes in a series of three experimental studies comprising 566 US-based participants recruited online via Amazon Mechanical Turk. Our results show that while certain attributes play an important role in the leader categorization process, others are less relevant. We also demonstrate that some attributes’ importance is contingent on the presence of other attributes and on the leadership schema type activated in respondents’ minds. Consistent with the Leadership Categorization Theory, our findings support the premise that individuals cognitively hold a superordinate leadership prototype, which imposes constraints on their more basic level prototypes. We discuss the implications of these results for leadership theory and practice.

  15. Experimental and geological approaches to elucidate chemical change in sporopollenin over geological time (United States)

    Fraser, Wesley; Lomax, Barry; Jardine, Phillip


    Sporopollenin is the primary biopolymer comprising the walls of sporomorphs (pollen and spores), both in extant material and found within the fossil record. Maturation processes associated with sedimentation and burial over geological timescales have long been considered to dramatically alter the chemical nature of organic material, most notably via oxidation. Here we present experimental data derived from simulated maturation, analyses of Carboniferous fossil material, and modern-day material. Our data demonstrate the core structure of sporopollenin undergoes only minor chemical adjustments at lower grades of maturation, with the over-riding chemical signature remaining identifiable as that of sporopollenin, showing strong resemblance to modern material. This modern signature can, in specific cases be preserved in the geological record, demonstrated by the near-pristine chemical composition of megaspores preserved in cave deposits of Pennsylvanian age (Carboniferous, c. 310 Ma). Conversely, the labile component associated with sporopollenin is found to readily defunctionalise and repolymerise to generate a new polyalkyl macromolecule in situ. The labile component is shown to be held in position via ester linkages; a common chemical feature observed in extant sporopollenin. This combined experimental and geological investigation provides insights into i) the preservation of chemical signatures within the fossil record, ii) considerations for sample preparation when undertaking chemical analysis of fossil sporomorphs, and iii) the long-term evolutionary stasis of sporopollenin, spanning geological time.

  16. Grafted natural polymer as new drag reducing agent: An experimental approach

    Directory of Open Access Journals (Sweden)

    Abdulbari Hayder A.


    Full Text Available The present investigation introduces a new natural drag reducing agent which has the ability to improve the flow in pipelines carrying aqueous or hydrocarbon liquids in turbulent flow. Okra (Abelmoschus esculentus mucilage drag reduction performance was tested in water and hydrocarbon (gas-oil media after grafting. The drag reduction test was conducted in a buildup closed loop liquid circulation system consists of two pipes 0.0127 and 0.0381 m Inside Diameter (ID, four testing sections in each pipe (0.5 to 2.0 m, tank, pump and pressure transmitters. Reynolds number (Re, additive concentration and the transported media type (water and gas-oil, were the major drag reduction variables investigated. The experimental results show that, new additive drag reduction ability is high with maximum percentage of drag reduction (%Dr up to 60% was achieved. The experimental results showed that the drag reduction ability increased by increasing the additive concentration. The %Dr was found to increase by increasing the Re by using the water-soluble additive while it was found to decrease by increasing the Re when using the oil-soluble additive. The %Dr was higher in the 0.0381 m ID pipe. Finally, the grafted and natural mucilage showed high resistance to shear forces when circulated continuously for 200 seconds in the closed-loop system.

  17. A combined modeling and experimental approach for achieving a simplified closed ecosystem. (United States)

    Turc, H A; Pintena, J; Bagarri, P; Gibiat, F; Fabreguettes, V


    In CELSS both biological and physico-chemical processes have to be used to support the main needs of the crews and to minimize the re-supply of food and air from Earth. The basic idea is to create a complete food chain (an artificial ecosystem), beginning from the crew, with its wastes, and returning to the crew to supply it with food and air. Two main other steps of this food chain are a waste treatment process and a biomass production including higher plants. We set up the connection of these key modules, which we called ECLAS (Ecosysteme Clos Artificiel Simplifie). A growth chamber containing higher plants is connected to a continuous supercritical water oxidation reactor, that converts the harvested biomass into carbon dioxide and enables the photosynthesis of the canopy. To achieve a stable coupling through optimized regulations between the modules, we programmed a modular numerical simulation of the system, in order to assess the involved fluxes and to constrain the last degrees of freedom of the experimental system already built. Simulation results and the first experimental results are here compared.

  18. Chronic intermittent hypoxia and obstructive sleep apnea: an experimental and clinical approach

    Directory of Open Access Journals (Sweden)

    Sforza E


    Full Text Available Emilia Sforza, Fréderic Roche Service de Physiologie Clinique et de l'Exercice, Pole NOL, CHU, EA SNA-EPIS 4607, Faculté de Médecine J. Lisfranc, UJM Saint-Etienne, Université de Lyon, Saint-Etienne, France Abstract: Obstructive sleep apnea (OSA is a prevalent sleep disorder considered as an independent risk factor for cardiovascular consequences, such as systemic arterial hypertension, ischemic heart disease, cardiac arrhythmias, metabolic disorders, and cognitive dysfunction. The pathogenesis of OSA-related consequence is assumed to be chronic intermittent hypoxia (IH inducing alterations at the molecular level, oxidative stress, persistent systemic inflammation, oxygen sensor activation, and increase of sympathetic activity. Overall, these mechanisms have an effect on vessel permeability and are considered to be important factors for explaining vascular, metabolic, and cognitive OSA-related consequences. The present review attempts to examine together the research paradigms and clinical studies on the effect of acute and chronic IH and the potential link with OSA. We firstly describe the literature data on the mechanisms activated by acute and chronic IH at the experimental level, which are very helpful and beneficial to explaining OSA consequences. Then, we describe in detail the effect of IH in patients with OSA that we can consider "the human model" of chronic IH. In this way, we can better understand the specific pathophysiological mechanisms proposed to explain the consequences of IH in OSA. Keywords: hypoxia, intermittent hypoxia, experimental studies, obstructive sleep apnea

  19. The Exploitation of Evolving Resources

    CERN Document Server

    McGlade, Jacqueline; Law, Richard


    The impact of man on the biosphere is profound. Quite apart from our capacity to destroy natural ecosystems and to drive species to extinction, we mould the evolution of the survivors by the selection pressures we apply to them. This has implications for the continued health of our natural biological resources and for the way in which we seek to optimise yield from those resources. Of these biological resources, fish stocks are particularly important to mankind as a source of protein. On a global basis, fish stocks provide the major source of protein for human consumption from natural ecosystems, amounting to some seventy million tonnes in 1970. Although fisheries management has been extensively developed over the last century, it has not hitherto considered the evolutionary consequences of fishing activity. While this omission may not have been serious in the past, the ever increasing intensity of exploitation and the deteriorating health of fish stocks has generated an urgent need for a better understanding...

  20. Exploiting pallidal plasticity for stimulation in Parkinson’s disease (United States)

    Lourens, Marcel A. J.; Schwab, Bettina C.; Nirody, Jasmine A.; Meijer, Hil G. E.; van Gils, Stephan A.


    Objective. Continuous application of high-frequency deep brain stimulation (DBS) often effectively reduces motor symptoms of Parkinson’s disease patients. While there is a growing need for more effective and less traumatic stimulation, the exact mechanism of DBS is still unknown. Here, we present a methodology to exploit the plasticity of GABAergic synapses inside the external globus pallidus (GPe) for the optimization of DBS. Approach. Assuming the existence of spike-timing-dependent plasticity (STDP) at GABAergic GPe-GPe synapses, we simulate neural activity in a network model of the subthalamic nucleus and GPe. In particular, we test different DBS protocols in our model and quantify their influence on neural synchrony. Main results. In an exemplary set of biologically plausible model parameters, we show that STDP in the GPe has a direct influence on neural activity and especially the stability of firing patterns. STDP stabilizes both uncorrelated firing in the healthy state and correlated firing in the parkinsonian state. Alternative stimulation protocols such as coordinated reset stimulation can clearly profit from the stabilizing effect of STDP. These results are widely independent of the STDP learning rule. Significance. Once the model settings, e.g., connection architectures, have been described experimentally, our model can be adjusted and directly applied in the development of novel stimulation protocols. More efficient stimulation leads to both minimization of side effects and savings in battery power.

  1. A review of active learning approaches to experimental design for uncovering biological networks.

    Directory of Open Access Journals (Sweden)

    Yuriy Sverchkov


    Full Text Available Various types of biological knowledge describe networks of interactions among elementary entities. For example, transcriptional regulatory networks consist of interactions among proteins and genes. Current knowledge about the exact structure of such networks is highly incomplete, and laboratory experiments that manipulate the entities involved are conducted to test hypotheses about these networks. In recent years, various automated approaches to experiment selection have been proposed. Many of these approaches can be characterized as active machine learning algorithms. Active learning is an iterative process in which a model is learned from data, hypotheses are generated from the model to propose informative experiments, and the experiments yield new data that is used to update the model. This review describes the various models, experiment selection strategies, validation techniques, and successful applications described in the literature; highlights common themes and notable distinctions among methods; and identifies likely directions of future research and open problems in the area.

  2. Challenges for complex microbial ecosystems: combination of experimental approaches with mathematical modeling. (United States)

    Haruta, Shin; Yoshida, Takehito; Aoi, Yoshiteru; Kaneko, Kunihiko; Futamata, Hiroyuki


    In the past couple of decades, molecular ecological techniques have been developed to elucidate microbial diversity and distribution in microbial ecosystems. Currently, modern techniques, represented by meta-omics and single cell observations, are revealing the incredible complexity of microbial ecosystems and the large degree of phenotypic variation. These studies propound that microbiological techniques are insufficient to untangle the complex microbial network. This minireview introduces the application of advanced mathematical approaches in combination with microbiological experiments to microbial ecological studies. These combinational approaches have successfully elucidated novel microbial behaviors that had not been recognized previously. Furthermore, the theoretical perspective also provides an understanding of the plasticity, robustness and stability of complex microbial ecosystems in nature.

  3. Experimental evaluation of a perspective tunnel display for three-dimensional helicopter approaches (United States)

    Grunwald, A. J.; Robertson, J. B.; Hatfield, J. J.


    A computer-generated perspective tunnel display for a steep and strongly curved three-dimensional helicopter approach is studied. The necessary control variables for following a curved trajectory are analyzed, the effectiveness of superimposed predictor symbology is investigated, and a suitable predictor law is formulated. The theoretical considerations are validated by an extensive fixed-base simulator program. The tunnel display with a superimposed predictor symbol is shown to outperform conventional-type displays in its abilities to follow a curved trajectory in the presence of gust disturbances, to enter the trajectory from an unknown position outside this trajectory, as well as to monitor automatic approaches. The feasibility of the tunnel display for operation in actual flight has been demonstrated in an exploratory flight test.

  4. Characterization of syntactic foams and their sandwich composites: Modeling and experimental approaches (United States)

    Gupta, Nikhil

    Hollow particle filled polymers known as syntactic foams are lightweight and highly damage tolerant. Syntactic foams are used as core materials in sandwich composites. The use of such materials in aeronautical and space structures make it necessary to understand their characteristics for various environmental and loading conditions. The first part of the present work takes modeling and finite element analysis approach to understand and predict the deformation behavior of syntactic foams. Contact analysis is performed on single particle models by the finite element analysis approach. In the second part extensive experiments are carried out to characterize syntactic foams for hygrothermal and compressive properties, and syntactic foam core sandwich composites for compressive and flexural properties. Flexural tests are carried out in three and four point bending and short beam shear configurations. Syntactic foams are tested in three different specimen sizes and orientations to characterize them as per the recommendations of various ASTM standards. Effect of specimen aspect ratio on the measured mechanical properties can be determined by such an approach. The effect of change in the internal radius of hollow particles, called cenospheres, on mechanical properties is studied for all these loading conditions. Five different types of cenospheres are selected fir the study of the internal radius dependence of mechanical properties of syntactic foams and their sandwich composites. All selected types of cenospheres have the same outer radius, however, their internal radius is different. Hence, difference in mechanical properties of syntactic foams is caused due to a difference in only one parameter, the cenosphere internal radius. Such unique approach made it possible to identify the individual contribution of matrix resin and cenospheres in the mechanical properties of syntactic foams. Specimen deformation behavior and fracture features are correlated to deformation curves

  5. A Combined Experimental and Numerical Approach to a Discrete Description of Indirect Reduction of Iron Oxide


    Peters, Bernhard; Hoffmann, F.; Senk, D.; Babich, A.; Hausemer, L.; Simoes, J.-P.


    Blast furnaces are complex counter-current reactors designed to reduce chemically iron oxides and melt them to liquid iron. The complex processes in blast furnace iron making involve various aspects of thermodynamics, fluid dynamics, chemistry and physics. Physical, thermal and chemical phenomena occurring within the process are highly coupled in time and space. In order to generate a more detailed understanding of the indirect reduction of iron ore, the innovative approach of the Extended D...

  6. Tumor Microenvironment In Experimental Models Of Human Cancer: Morphological Investigational Approaches

    Directory of Open Access Journals (Sweden)

    Lucia Minoli


    Discussion and conclusions. Due to the microenvironmental heterogeneity which influence tumor development and biological behavior, a sole quantification is unreliable for characterizing the TME. Considering that, morphological techniques proved to be a valuable approach, allowing the evaluation of the spatial distribution and mutual interaction between the different elements. Additional studies are needed for further investigate the biological significance of spatial distribution of the components of the TME.

  7. Quantitative, Non-Experimental Approaches to the Microeconomic Evaluation of Public Policy Measures : a Survey


    Keilbach, Max


    The objective of evaluating public policy measures is to assess its implications and thus to obtain a measure for weather the respective program has been successful. In this paper, we consider and classify microeconomic and microeconometric approaches to measuring this success. To do so, the evaluation problem is outlined and three estimation priciples are presented. For each of these, underlying assumptions are identified and the consequences of their violation discussed.

  8. Approach to Operational Experimental Estimation of Static Stresses of Elements of Mechanical Structures (United States)

    Sedov, A. V.; Kalinchuk, V. V.; Bocharova, O. V.


    The evaluation of static stresses and strength of units and components is a crucial task for increasing reliability in the operation of vehicles and equipment, to prevent emergencies, especially in structures made of metal and composite materials. At the stage of creation and commissioning of structures to control the quality of manufacturing of individual elements and components, diagnostic control methods are widely used. They are acoustic, ultrasonic, X-ray, radiation methods and others. The using of these methods to control the residual life and the degree of static stresses of units and parts during operation is fraught with great difficulties both in methodology and in instrumentation. In this paper, the authors propose an effective approach of operative control of the degree of static stresses of units and parts of mechanical structures which are in working condition, based on recording the changing in the surface wave properties of a system consisting of a sensor and a controlled environment (unit, part). The proposed approach of low-frequency diagnostics of static stresses presupposes a new adaptive-spectral analysis of a surface wave created by external action (impact). It is possible to estimate implicit stresses of structures in the experiment due to this approach.

  9. The influence of parent's body mass index on peer selection: an experimental approach using virtual reality. (United States)

    Martarelli, Corinna S; Borter, Natalie; Bryjova, Jana; Mast, Fred W; Munsch, Simone


    Relatively little is known about the influence of psychosocial factors, such as familial role modeling and social network on the development and maintenance of childhood obesity. We investigated peer selection using an immersive virtual reality environment. In a virtual schoolyard, children were confronted with normal weight and overweight avatars either eating or playing. Fifty-seven children aged 7-13 participated. Interpersonal distance to the avatars, child's BMI, self-perception, eating behavior and parental BMI were assessed. Parental BMI was the strongest predictor for the children's minimal distance to the avatars. Specifically, a higher mothers' BMI was associated with greater interpersonal distance and children approached closer to overweight eating avatars. A higher father's BMI was associated with a lower interpersonal distance to the avatars. These children approached normal weight playing and overweight eating avatar peers closest. The importance of parental BMI for the child's social approach/avoidance behavior can be explained through social modeling mechanisms. Differential effects of paternal and maternal BMI might be due to gender specific beauty ideals. Interventions to promote social interaction with peer groups could foster weight stabilization or weight loss in children. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  10. Experimental approach to domino-style basement fault systems with evaporites during extension and subsequent inversion (United States)

    Ferrer, Oriol; McClay, Ken


    Salt is mechanically weaker than other sedimentary rocks in rift basins. During extension it commonly acts as a strain localizer, decoupling supra- and sub-salt deformation. In this scenario the movement of the subsalt faults combined with the salt migration commonly constraint the development of syncline basins. The shape of these synclines is basically controlled by the thickness and strength of the overlying salt section, as well as by the shapes of the extensional faults, and the magnitudes and slip rates along the faults. The inherited extensional structure, and particularly the continuity of the salt section, plays a key role if the rift basin is subsequently inverted. This research utilizes scaled physical models to analyse the interplay between subsalt structures and suprasalt units during both extension and inversion in domino-style basement fault systems. The experimental program includes twelve analogue models to analyze how the thickness and stratigraphy of the salt unit as well as the thickness of the pre-extensional cover constraint the structural style during extension and subsequent inversion. Different models with the same setup have been used to examine the kinematic evolution. Model kinematics was documented and analyzed combining high-resolution photographs and sub-millimeter resolution scanners. The vertical sections carried out at the end of the experiments have been used to characterize the variations of the structures along strike using new methodologies (3D voxel models in image processing software and 3D seismic). The experimental results show that after extension, rift systems with salt affected by domino-style basement faults don't show the classical growth stratal wedges. In this case synclinal basins develop above the salt on the hangingwall of the basement faults. The evolution of supra- and subsalt deformation is initially decoupled by the salt layer. Salt migrates from the main depocenters towards the edges of the basin constraining

  11. New concepts, experimental approaches, and dereplication strategies for the discovery of novel phytoestrogens from natural sources. (United States)

    Michel, Thomas; Halabalaki, Maria; Skaltsounis, Alexios-Leandros


    Phytoestrogens constitute an attractive research topic due to their estrogenic profile and their biological involvement in woman's health. Therefore, numerous studies are currently performed in natural products chemistry area aiming at the discovery of novel phytoestrogens. The main classes of phytoestrogens are flavonoids (flavonols, flavanones), isoflavonoids (isoflavones, coumestans), lignans, stilbenoids as well as miscellaneous chemical groups abundant in several edible and/or medicinal plants, belonging mostly to the Leguminosae family. As for other bioactives, the detection of new structures and more potent plant-derived phytoestrogens typically follows the general approaches currently available in the natural product discovery process. Plant-based approaches selected from traditional medicine knowledge and bioguided concepts are routinely employed. However, these approaches are associated with serious disadvantages such as time-consuming, repeated, and labor intensive processes as well as lack of specificity and reproducibility. In recent years, the natural products chemistry became more technology-driven, and several different strategies have been developed. Structure-oriented procedures and miniaturized approaches employing advanced hyphenated analytical platforms have recently emerged. They facilitate significantly not only the discovery of novel phytoestrogens but also the dereplication procedure leading to the anticipation of major drawbacks in natural products discovery. In this review, apart from the traditional concepts followed in phytochemistry for the discovery of novel biologically active compounds, recent applications in the field of extraction, analysis, fractionation, and identification of phytoestrogens will be discussed. Moreover, specific methodologies combining identification of actives and biological evaluation in parallel, such as liquid chromatography-biochemical detection, frontal affinity chromatography-mass spectrometry and pulsed

  12. Conductance-based refractory density approach: comparison with experimental data and generalization to lognormal distribution of input current. (United States)

    Chizhov, Anton V


    The conductance-based refractory density (CBRD) approach is an efficient tool for modeling interacting neuronal populations. The model describes the firing activity of a statistical ensemble of uncoupled Hodgkin-Huxley-like neurons, each receiving individual Gaussian noise and a common time-varying deterministic input. However, the approach requires experimental validation and extension to cases of distributed input signals (or input weights) among different neurons of such an ensemble. Here the CBRD model is verified by comparing with experimental data and then generalized for a lognormal (LN) distribution of the input weights. The model with equal weights is shown to reproduce efficiently the post-spike time histograms and the membrane voltage of experimental multiple trial response of single neurons to a step-wise current injection. The responses reveal a more rapid reaction of the firing-rate than voltage. Slow adaptive potassium channels strongly affected the shape of the responses. Next, a computationally efficient CBRD model is derived for a population with the LN input weight distribution and is compared with the original model with equal input weights. The analysis shows that the LN distribution: (1) provides a faster response, (2) eliminates oscillations, (3) leads to higher sensitivity to weak stimuli, and (4) increases the coefficient of variation of interspike intervals. In addition, a simplified firing-rate type model is tested, showing improved precision in the case of a LN distribution of weights. The CBRD approach is recommended for complex, biophysically detailed simulations of interacting neuronal populations, while the modified firing-rate type model is recommended for computationally reduced simulations.

  13. Experimental and modelling approaches for characterizing stream water-groundwater mixing and dynamic in the hyporheic zone (United States)

    Houzé, Clémence; Durand, Véronique; Pessel, Marc; Mugler, Claude; Mouche, Emmanuel; Varnède, Lucie


    The hyporheic zone, which is a near-channel zone of surface water-groundwater mixing, has a major importance in the functioning of ecosystems and reflects the whole ecological state of a river. As a consequence, a good understanding of the processes involved in the hyporheic zone is essential for river restoration. In the present work, we used both experimental and modelling approaches for characterizing stream water - groundwater mixing and dynamic in the Essonne River (France). The experimental approach was based on geophysical and geochemical tools that give complementary results; water analyses are punctual whereas geophysical surveys give a continuous 2D model of the distribution of some parameters in the subsurface. The river was instrumented with several electrodes lines for electrical resistivity tomography (ERT), and multi-sampling systems to collect pore water from several depths within the streambed sediments. Precise topography of every electrode, piezometer and sampling system was done in order to understand the possible effect of streambed topography on observed measurements. An artificial flood was reproduced during a dam controlled experiment. The dam level downstream the studied area was lowered and raised in order to simulate a flood without any additional contribution from runoff. Another experiment was performed to follow the river water into the streambed sediments. Salt was added into the stream and followed with a high resolution monitoring. Results from the different experiments showed that is it possible to follow the hyporheic zone dynamic thanks to different varieties of tools. The geophysical surveys indicate a clear change in resistivity of the streambed sediments when the water chemistry of the stream changes, along with the dam experiment. The end of the monitoring highlights a quite rapid return to the stable state despite some hysteresis observed in electric measurements. In the modelling approach, we used a 3D distributed model

  14. Assisting children born of sexual exploitation and abuse

    Directory of Open Access Journals (Sweden)

    Lauren Rumble


    Full Text Available The UN Secretary-General has issued a strategy tosupport victims of sexual exploitation and abuse by UNstaff. It includes a controversial proposal to introduceDNA sampling for all UN staff. Unless this suggestionis adopted, an important opportunity to implementa truly survivor-centred approach may be lost.

  15. Exploiting network redundancy for low-cost neural network realizations.

    NARCIS (Netherlands)

    Keegstra, H; Jansen, WJ; Nijhuis, JAG; Spaanenburg, L; Stevens, H; Udding, JT


    A method is presented to optimize a trained neural network for physical realization styles. Target architectures are embedded microcontrollers or standard cell based ASIC designs. The approach exploits the redundancy in the network, required for successful training, to replace the synaptic weighting

  16. Experimental Approach to the QCD Phase Diagram - Beam Energy Scan at RHIC (United States)

    Odyniec, G.


    The QCD phase diagram appears to be the most important single figure of our field. While recent progress in Lattice QCD (LQCD) and model calculations is impressive, the location of phase boundaries and the exact position of the hypothetical critical point (CP) remains unknown. The available theoretical estimates, however, indicate that the critical point might be in the region of the phase diagram probed by current heavy ion experiments. The Beam Energy Scan (BES) program at RHIC, described in this paper, was launched to expand the experimental study where theory cannot yet reach. Both large RHIC experiments, STAR and PHENIX, are in the process of preparing for the first run. Particularly STAR with its large, uniform acceptance and excellent particle identification capabilities, is uniquely positioned to cover this physics in unprecedented depth and detail.

  17. An approach to eliminate stepped features in multistage incremental sheet forming process: Experimental and FEA analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nirala, Harish Kumar; Jain, Prashant K.; Tandon, Puneet [PDPM Indian Institute of Information Technology, Design and Manufacturing Jabalpur Jabalpur-482005, Madhya Pradesh (India); Roy, J. J.; Samal, M. K. [Bhabha Atomic Research Centre, Mumbai (India)


    Incremental sheet forming (ISF) is a recently developed manufacturing technique. In ISF, forming is done by applying deformation force through the motion of Numerically controlled (NC) single point forming tool on the clamped sheet metal blank. Single Point Incremental sheet forming (SPISF) is also known as a die-less forming process because no die is required to fabricate any component by using this process. Now a day it is widely accepted for rapid manufacturing of sheet metal components. The formability of SPISF process improves by adding some intermediate stages into it, which is known as Multi-stage SPISF (MSPISF) process. However during forming in MSPISF process because of intermediate stages stepped features are generated. This paper investigates the generation of stepped features with simulation and experimental results. An effective MSPISF strategy is proposed to remove or eliminate this generated undesirable stepped features.

  18. Effects of organic enrichment on macrofauna community structure: an experimental approach

    Directory of Open Access Journals (Sweden)

    Rodrigo Riera


    Full Text Available The determination of the resilience of benthic assemblages is a capital issue for the off-shore aquaculture industry in its attempts to minimize environmental disturbances. Experimental studies are an important tool for the establishment of thresholds for macrofaunal assemblages inhabiting sandy seabeds. An experiment was conducted with three treatments (Control, 1x and 3x,in which organic load (fish pellets was added (1x (10 g of fish pellets and 3x (30 g. A reduction in abundance of individuals and species richness was found as between the control and organic-enriched treatments. Significant changes in assemblage structure were also found, mainly due to the decrease of the sensitive tanaid Apseudes talpa in organically-enriched treatments. AMBI and M-AMBI indices were calculated and a decrease of ecological status was observed in treatment 3x.

  19. An alternative approach to analysis of mental states in experimental social cognition research. (United States)

    Lench, Heather C; Taylor, Aaron B; Bench, Shane W


    Establishing the mental states that affect human behavior is a primary goal of experiments on social cognitive processes. Such mental states can be manipulated only indirectly; therefore, after delivering a manipulation, researchers attempt to verify that the mental state of interest, the representation of a mental state, was in fact changed by the manipulation and that this change caused the observed effect. The usual procedure is to examine mean differences in a measure of the mental state of interest (a manipulation check) among experimental conditions and to infer whether the manipulation was effective. We describe a procedure that strengthens the construct validity of manipulations and, hence, causal inferences in experiments that focus on mental states using analyses familiar to most researchers. This procedure employs a traditional manipulation check that assesses the relationship between manipulations and mental states but, additionally, tests the relationship between the manipulation check and dependent measure.

  20. Experimental approach to interaction physics challenges of the shock ignition scheme using short pulse lasers. (United States)

    Goyon, C; Depierreux, S; Yahia, V; Loisel, G; Baccou, C; Courvoisier, C; Borisenko, N G; Orekhov, A; Rosmej, O; Labaune, C


    An experimental program was designed to study the most important issues of laser-plasma interaction physics in the context of the shock ignition scheme. In the new experiments presented in this Letter, a combination of kilojoule and short laser pulses was used to study the laser-plasma coupling at high laser intensities for a large range of electron densities and plasma profiles. We find that the backscatter is dominated by stimulated Brillouin scattering with stimulated Raman scattering staying at a limited level. This is in agreement with past experiments using long pulses but laser intensities limited to 2×10(15)  W/cm2, or short pulses with intensities up to 5×10(16)  W/cm2 as well as with 2D particle-in-cell simulations.

  1. Experimental studies of low salinity water flooding in carbonate reservoirs: A new promising approach

    DEFF Research Database (Denmark)

    Zahid, Adeel; Shapiro, Alexander; Skauge, Arne


    reservoirs. In this paper, we have experimentally investigated the oil recovery potential of low salinity water flooding for carbonate rocks. We used both reservoir carbonate and outcrop chalk core plugs. The flooding experiments were carried out initially with the seawater, and afterwards additional oil...... recovery was evaluated by sequential injection of various diluted seawater. The experiments applied stepwise increase in flow rate to eliminate the influence of possible capillary end effect. The total oil recovery, interaction of the different ions with the rock, and the wettability changes were studied......Low salinity water flooding is well studied for sandstone reservoirs, both laboratory and field tests have showed improvement in the oil recovery in many cases. Up to very recently, the low salinity effect has been indeterminated for carbonates. Most recently, Saudi Aramco reported that substantial...

  2. Blister formation and hydrogen retention in aluminium and beryllium: A modeling and experimental approach

    Directory of Open Access Journals (Sweden)

    C. Quirós


    Full Text Available Experiments were performed in a low pressure-high density plasma reactor in order to study the impact of hydrogen retention in aluminium under plasma conditions. Microscopy scans of the surface were performed before and after 1h plasma exposure (fluence 6.1 ×1023ions/m2 where it is seen that blisters start to nucleate at the grain boundaries. Investigation on blister growth kinetics was performed for fluences ranging between 6 ×1023 and 3.7 ×1024ions/m2. The evolution of the characteristic size of the projected area was also analyzed. Finally, a macroscopic rate equations (MRE code was used to simulate hydrogen retention and diffusion in Al and bubble growth in the bulk was simulated using experimental results. This model was also used to simulate these phenomena in Be and compare its behavior with respect to Al.

  3. On the impact of non-Gaussian wind statistics on wind turbines - an experimental approach (United States)

    Schottler, Jannik; Reinke, Nico; Hoelling, Agnieszka; Whale, Jonathan; Peinke, Joachim; Hoelling, Michael


    The effect of intermittent and Gaussian inflow conditions on wind energy converters is studied experimentally. Two different flow situations were created in a wind tunnel using an active grid. Both flows exhibit nearly equal mean velocity values and turbulence intensities, but strongly differ in their two point uτ = u (t + τ) - u (t) on a variety of time scales τ, one being Gaussian distributed, the other one being strongly intermittent. A horizontal axis model wind turbine is exposed to both flows, isolating the effect of the differences not captured by mean values and turbulence intensities on the turbine. Thrust, torque and power data were recorded and analyzed, showing that the model turbine does not smooth out intermittency. Intermittent inflow is converted to similarly intermittent turbine data on all scales considered, reaching down to sub-rotor scales in space, indicating that it is not correct to assume a smoothing of wind speed fluctuations below the size of the rotor.

  4. Nonlinear magneto-electro-thermo-mechanical response of layered magnetoelectric composites: theoretical and experimental approach (United States)

    Subhani, Sk M.; Maniprakash, S.; Arockiarajan, A.


    Composite structures exhibiting magnetoelectric (ME) coupling behavior have applications in various fields such as energy harvesting, sensors and actuators. ME coupling behavior is considered to occur by transfer of strain through bonding of the constituent phases of the ME composite. Here, the influence of thermal environment on the constitutive behavior of ferroic phases was examined, firstly by conducting experiments at various temperatures. To mimic the constitutive behavior of ferroic phases, constitutive models were built based on a thermodynamic framework. In order to account for thermal effects, appropriate functions were introduced to the formulation. Model parameters were chosen based on experimental data and simulation studies were performed. The obtained results were found to be in agreement with the experiments. Additionally, an attempt was made to capture the mechanical, electrical, magnetic and ME coupling behavior of composites. To capture the response of ME composites, a homogenization technique was employed along with the proposed constitutive relation for the constituent phases of an ME composite.


    Directory of Open Access Journals (Sweden)

    M. R. Monazzam, A. Nezafat


    Full Text Available Noise is one of the most serious challenges in modern community. In some specific industries, according to the nature of process, this challenge is more threatening. This paper describes a means of noise control for spinning machine based on experimental measurements. Also advantages and disadvantages of the control procedure are added. Different factors which may affect the performance of the barrier in this situation are also mentioned. To provide a good estimation of the control measure, a theoretical formula is also described and it is compared with the field data. Good agreement between the results of filed measurements and theoretical presented model was achieved. No obvious noise reduction was seen by partial indoor barriers in low absorbent enclosed spaces, since the reflection from multiple hard surfaces is the main dominated factor in the tested environment. At the end, the situation of the environment and standards, which are necessary in attaining the ideal results, are explained.

  6. Temporal and Spatio-Temporal Dynamic Instabilities: Novel Computational and Experimental approaches (United States)

    Doedel, Eusebius J.; Panayotaros, Panayotis; Lambruschini, Carlos L. Pando


    This special issue contains a concise account of significant research results presented at the international workshop on Advanced Computational and Experimental Techniques in Nonlinear Dynamics, which was held in Cusco, Peru in August 2015. The meeting gathered leading experts, as well as new researchers, who have contributed to different aspects of Nonlinear Dynamics. Particularly significant was the presence of many active scientists from Latin America. The topics covered in this special issue range from advanced numerical techniques to novel physical experiments, and reflect the present state of the art in several areas of Nonlinear Dynamics. It contains seven review articles, followed by twenty-one regular papers that are organized in five categories, namely (1) Nonlinear Evolution Equations and Applications, (2) Numerical Continuation in Self-sustained Oscillators, (3) Synchronization, Control and Data Analysis, (4) Hamiltonian Systems, and (5) Scaling Properties in Maps.

  7. Sustainable Approaches for Stormwater Quality Improvements with Experimental Geothermal Paving Systems

    Directory of Open Access Journals (Sweden)

    Kiran Tota-Maharaj


    Full Text Available This research assesses the next generation of permeable pavement systems (PPS incorporating ground source heat pumps (geothermal paving systems. Twelve experimental pilot-scaled pavement systems were assessed for its stormwater treatability in Edinburgh, UK. The relatively high variability of temperatures during the heating and cooling cycle of a ground source heat pump system embedded into the pavement structure did not allow the ecological risk of pathogenic microbial expansion and survival. Carbon dioxide monitoring indicated relatively high microbial activity on a geotextile layer and within the pavement structure. Anaerobic degradation processes were concentrated around the geotextile zone, where carbon dioxide concentrations reached up to 2000 ppm. The overall water treatment potential was high with up to 99% biochemical oxygen demand removal. The pervious pavement systems reduced the ecological risk of stormwater discharges and provided a low risk of pathogen growth.

  8. Flow and regulatory compatibility: an experimental approach to the flow model of intrinsic motivation. (United States)

    Keller, Johannes; Bless, Herbert


    The authors propose that the experience of flow (Csikszentmihalyi, 2000) as reflected in the deep involvement in an activity perceived as intrinsically rewarding represents a regulatory compatibility experience. The research addresses the notion that the compatibility of critical person (e.g., skills) and environmental factors (e.g., demands) involved in a given activity elicits subjective experiences that render the respective activity rewarding. Two studies are reported that investigate the consequences of compatibility of skills and task demands during task engagement. Departing from correlational research, the present studies employ a newly developed experimental paradigm to document the causal impact of such a skills/demands compatibility on the emergence of flow. Experiment 2 revealed that individuals characterized by a strong habitual action-orientation were most sensitive to the manipulation of the skills-demands compatibility.

  9. Impact of drilling fluids on seagrasses: an experimental community approach (journal version)

    Energy Technology Data Exchange (ETDEWEB)

    Morton, R.D.; Duke, T.W.; Macauley, J.M.; Clark, J.R.; Price, W.A.


    Effects of a used drilling fluid on an experimental seagrass community (Thalassia testudinum Konig et Sims) were measured by exposing the community to the suspended particulate phase (SPP) in laboratory microcosms. Structure of the macroinvertebrate assemblage, growth, and chlorophyll content of grass and associated epiphytes, and rates of decomposition as indicated by weight loss of grass leaves in treated and untreated microcosms were compared. There were statistically significant differences in community structure and function among untreated microcosms and those receiving the clay and drilling fluid. For example, drilling fluid and clay caused a significant decrease in the numbers of the ten most numerically abundant (dominant) macroinvertebrates, and drilling fluid decreased the rate at which Thalassia leaves decomposed.

  10. Successional colonization of temporary streams: An experimental approach using aquatic insects (United States)

    Godoy, Bruno Spacek; Queiroz, Luciano Lopes; Lodi, Sara; Nascimento de Jesus, Jhonathan Diego; Oliveira, Leandro Gonçalves


    The metacommunity concept studies the processes that structure communities on local and regional scales. This concept is useful to assess spatial variability. However, temporal patterns (e.g., ecological succession and colonization) are neglected in metacommunity studies, since such patterns require temporally extensive, and hard to execute studies. We used experimental habitats in temporary streams located within the Brazilian Cerrado to evaluate the importance of succession for the aquatic insect metacommunity. Five artificial habitats consisting of wrapped crushed rock were set transversally to the water flow in five streams. The habitats were sampled weekly to assess community composition, and replaced after sampling to identify new potential colonizers. We analyzed the accumulation of new colonizers after each week using a logistic model. We selected pairs of experimental habitats and estimated the Bray-Curtis dissimilarity index to assess the community composition trajectory during the experiment. We used the dissimilarity values in ANOVA tests, identifying the importance of time and space for the community. The number of new taxa stabilized in the third week, and we estimated a weekly increase of 1.61 new taxa in the community after stabilization. The overall pattern was a small change on community composition, but one stream had a higher weekly turnover. Our results showed a relevant influence of time in the initial communities of aquatic insects of temporary streams. However, we must observe the temporal pattern in a spatial context, once different streams have different successional history regarding number of taxa and community turnover. We highlight the importance of aerial dispersal and movement to seek oviposition sites as an important factor in determining colonization patterns.

  11. Effects of avian cholera on survival of Lesser Snow geese Anser caerulescens: An experimental approach (United States)

    Samuel, Michael D.; Takekawa, John Y.; Baranyuk, Vasily V.; Orthmeyer, Dennis L.


    Avian cholera, caused by the bacterium Pasteurella multocida, is one of the most important diseases affecting waterfowl in North America but little is known about the epizootiology of this disease or its impacts on annual survival rates. We ringed Lesser Snow Geese Anser caerulescens nesting at Wrangel Island, Russia and Banks Island, Canada with metal rings and individually coded plastic neck-collars or radio-transmitters to determine survival, movement and cause of death. We vaccinated half of the neck-collared and radiotagged geese to provide protection from avian cholera for up to one year following ringing and thus experimentally determine the impacts of this disease on survival. We found that vaccination did not reduce short-term survival of the experimental birds, compared with control geese. Neck-collared geese vaccinated in 1993 at Wrangel Island had higher survival during winter 1993–94 than control birds. In contrast, we found similar survival during winter 1994–95 between vaccinated and control geese neck-collared in 1994 at Wrangel and Banks Islands. Survival of radiotagged geese on wintering areas during 1994–95 was consistent with the vaccination versus control results for neck-collared geese during the same winter. However, we found that radiotagged geese that were vaccinated had better survival than control geese during winter 1995–96. We believe that harvest and avian cholera are the two principal causes of mortality for Lesser Snow Geese wintering in the Pacific Flyway and that avian cholera may be one of the factors affecting these populations.

  12. Theoretical and Experimental Approaches to the Dark Energy and the Cosmological Constant Problem (United States)

    Borzou, Ahmad

    The cosmological constant problem is one of the most pressing problems of physics at this time. In this dissertation the problem and a set of widely-discussed theoretical solutions to this problem are reviewed. It is shown that a recently developed Lorentz gauge theory of gravity can provide a natural solution. In this theory presented here, the metric is not dynamical and it is shown that the Schwartzschild metric is an exact solution. Also, it is proven that the de Sitter space is an exact vacuum solution and as a result the theory is able to explain the expansion of the universe with no need for dark energy. Renormalizability of the theory is studied as well. It is also shown that, under a certain condition, the theory is power-counting renormalizable. Supersymmetry provides an alternative solution to the cosmological problem as well. The idea behind supersymmetry is reviewed and an experimental search for supersymmetry is presented. The experimental search discussed in this dissertation is based on all-hadronic events with large missing transverse momentum produced in proton-proton collisions at √s = 13TeV. The data sample, corresponding to an integrated luminosity of 2.3fb -1, was collected with the CMS detector at the CERN LHC in 2015. The data are examined in search regions defined with jet multiplicity, tagged bottom quark jet multiplicity, missing transverse momentum, and the scalar sum of jet transverse momenta. The observed numbers of events in all search regions are found to be consistent with the expectations from standard model processes. Exclusion limits are presented for simplified supersymmetric models for pair production of gluinos, supersymmetric partners of gluons. Depending on the assumed gluino decay mechanism, and for a massless, weakly interacting, lightest neutralino, lower limits on the gluino mass from 1440 to 1600\\GeV are obtained, significantly extending previous limits.

  13. Estimation of break-lock in PLL synthesizers for monopulse radar applications: Experimental and simulation approach

    Directory of Open Access Journals (Sweden)

    Harikrishna Paik


    Full Text Available This work presents and estimates the break-lock in phase locked loop (PLL synthesizers for monopulse radar applications through experimental measurements and computer simulation. Sinusoidal continuous wave (CW and linear frequency modulated (LFM signals are used as repeater jamming signals. The CW jamming signal power as a function of radar echo signal power at break-lock is estimated for different values of frequency difference between these two signals, and from these results the jammer to echo signal power (J/S ratio (in dB is computed. Break-lock is achieved at a J/S ratio of 1.9 dB (measured at 1.8 dB for a typical echo signal power of −5 dBm with a 1 MHz frequency difference. The frequency deviation as a function of J/S ratio required to break-lock is estimated for different modulation rates in the presence of LFM jamming signal. Break-lock is achieved at a frequency deviation of 0.34 MHz (measured at 0.32 MHz for a J/S ratio of 2 dB and 200 kHz modulation rate. The simulation models are proposed accordingly to the data obtained from the experimental setups. Good and consistent agreements between the measured and simulated results are observed and can be useful in the design of CW and LFM jammers in the target platform.

  14. Phase equilibrium of liquid mixtures: experimental and modeled data using statistical associating fluid theory for potential of variable range approach. (United States)

    Giner, Beatriz; Bandrés, Isabel; López, M Carmen; Lafuente, Carlos; Galindo, Amparo


    A study of the phase equilibrium (experimental and modeled) of mixtures formed by a cyclic ether and haloalkanes has been derived. Experimental data for the isothermal vapor liquid equilibrium of mixtures formed by tetrahydrofuran and tetrahydropyran and isomeric chlorobutanes at temperatures of 298.15, 313.15, and 328.15 K are presented. Experimental results have been discussed in terms of both molecular characteristics of pure compounds and potential intermolecular interaction between them using thermodynamic information of the mixtures obtained earlier. The statistical associating fluid theory for potential of variable range (SAFT-VR) approach together with standard combining rules without adjustable parameters has been used to model the phase equilibrium. Good agreement between experiment and the prediction is found with such a model. Mean absolute deviations for pressures are of the order of 1 kPa, while less than 0.013 mole fraction for vapor phase compositions. In order to improve the results obtained, a new modeling has been carried out by introducing a unique transferable parameter k(ij), which modifies the strength of the dispersion interaction between unlike components in the mixtures, and is valid for all the studied mixtures being not temperature or pressure dependent. This parameter together with the SAFT-VR approach provides a description of the vapor-liquid equilibrium of the mixtures that is in excellent agreement with the experimental data for most cases. The absolute deviations are of the order of 0.005 mole fraction for vapor phase compositions and less than 0.3 kPa for pressure, excepting for mixtures containing 2-chloro-2-methylpropane which deviations for pressure are larger. Results obtained in this work in the modeling of the phase equilibrium with the SAFT-VR equation of state have been compared to the ones obtained in a previous study when the approach was used to model similar mixtures with clear differences in the thermodynamic behavior

  15. Genetic rodent models of brain disorders: Perspectives on experimental approaches and therapeutic strategies. (United States)

    McGraw, Christopher M; Ward, Christopher S; Samaco, Rodney C


    Neurobehavioral disorders comprised of neurodegenerative, neurodevelopmental, and psychiatric disorders together represent leading causes of morbidity and mortality. Despite significant academic research and industry efforts to elucidate the disease mechanisms operative in these disorders and to develop mechanism-based therapies, our understanding remains incomplete and our access to tractable therapeutic interventions severely limited. The magnitude of these short-comings can be measured by the growing list of disappointing clinical trials based on initially promising compounds identified in genetic animal models. This review and commentary will explore why this may be so, focusing on the central role that genetic models of neurobehavioral disorders have come to occupy in current efforts to identify disease mechanisms and therapies. In particular, we will highlight the unique pitfalls and challenges that have hampered success in these models as compared to genetic models of non-neurological diseases as well as to symptom-based models of the early 20th century that led to the discovery of all major classes of psychoactive pharmaceutical compounds still used today. Using examples from specific genetic rodent models of human neurobehavioral disorders, we will highlight issues of reproducibility, construct validity, and translational relevance in the hopes that these examples will be instructive toward greater success in future endeavors. Lastly, we will champion a two-pronged approach toward identifying novel therapies for neurobehavioral disorders that makes greater use of the historically more successful symptom-based approaches in addition to more mechanism-based approaches. © 2017 The Authors. American Journal of Medical Genetics Part C Published by Wiley Periodicals, Inc.

  16. [Transgastric laparo-endoscopic approach for difficult access lesions. Experimental mode]. (United States)

    Tapia-Vega, Marcel Adalid; Morales-Chávez, Carlos Ernesto; Aguirre-Olmedo, Itzé; Cuendis-Velázquez, Adolfo; Rojano-Rodríguez, Martín Edgardo; Cárdenas-Lailson, Luis Eduardo


    Gastric neoplasms can be treated by laparoscopy in a safe and efficient way. Some lesions are not accessible to laparoscopic surgery due to their location. A transgastric approach is proposed as an alternative. Show the results with the application of an endoscopic laparotomy in an animal model that maintains functional anatomy, to resect the posterior gastric neoplasms of the stomach wall, close to the cardia and pre-pyloric region. The laparo-endoscopic technique for resection of gastric neoplasms located in the posterior wall was developed in twelve pigs at the Hospital General Gea González from May to December 2011. An endoscopy was performed to establish the site of insertion of intragastric trocars. Three gastrotomies were made in the anterior wall; under endoscopic and laparoscopic vision the trocars were inserted. The stomach was insufflated with CO2. The lesion was resected maintaining a 20 mm circumferencial margin. The gastrotomies were sutured. The statistic analysis was made with t Student and exact Fisher tests. One-hundred percent of resections were achieved in an average time of 102.33 minutes (± 4.50). Two complications and no transoperatory deceases occurred. The technique we describe allows an appropriate approach to gastric lesions located in the posterior wall, those near to the esophagogastric juntion and the prepiloric region, due to the excellent exposure managed by working inside the stomach with a laparoscopic vision and the two intragastric movile ports. The laparoscopic transgastric approach is feasible and safe for the resection of gastric neoplasms located in the posterior wall, those close to the esophago-gastric junction, and the pre-pyloric region.

  17. Preliminary Experimental Verification of Synthetic Aperture Flow Imaging Using a Dual Stage Beamformer Approach

    DEFF Research Database (Denmark)

    Li, Ye; Jensen, Jørgen Arendt


    A dual stage beamformer method for synthetic aperture flow imaging has been developed. The motivation is to increase the frame rate and still maintain a beamforming quality sufficient for flow estimation that is possible to implement in a commercial scanner. With the new method high resolution...... images can be obtained continuously, which will highly increase the frame rate. The flow velocity is estimated by using a time-domain cross-correlation technique. The approach is investigated through experiments with the SARUS scanner (Synthetic Aperture Real-time Ultrasound System). A flow rig generates...

  18. Experimental demonstration of a classical approach for flexible space structure control: NASA CSI testbeds (United States)

    Bond, Wie


    The results of active control experiments performed for the Mini-Mast truss structure are presented. The primary research objectives were: (1) to develop active structural control concepts and/or techniques; (2) to verify the concept of robust non-minimum-phase compensation for a certain class of non-colocated structural control problems through ground experiments; (3) to verify a 'dipole' concept for persistent disturbance rejection control of flexible structures; and (4) to identify CSI (Control Structure Interaction) issues and areas of emphasis for the next generation of large flexible spacecraft. The classical SISO (Single Input and Single Output) control design approach was employed.

  19. Experimental approaches to study the nutritional value of food ingredients for dogs and cats

    Directory of Open Access Journals (Sweden)

    David L. Harmon


    Full Text Available This review covers methods that have been applied to study the nutrient value or quality of specific ingredients fed to dogs, cats and comparable species (i.e. foxes, minks, rats, etc.. Typically, the nutritional value or utilization of a specific ingredient is measured by total tract digestibility and has been expanded through the measurement of total nutrient balance (i.e. nitrogen or energy. However, to better understand digestion it is necessary to obtain a more accurate measurement of nutrients entering and leaving the small intestine. Accurate measurement of small intestinal digestion is crucial in dogs and cats because nutrient digestion and absorption occurs primarily in the small intestine. Measuring small intestinal digestibility requires access to digesta leaving the small intestine and can be obtained by placing a cannula at the terminal ileum. This approach also necessitates the use of markers (e.g. chromic oxide to monitor flow of digesta. Specifically, this approach has been used for the direct measurement of intestinal digestion of carbohydrates and amino acids. It also permits a separate measurement of large intestinal digestion which is particularly useful for the study of fiber fermentation. Passage of foods through the gastrointestinal tract is also an important component of utilization and these methods are reviewed.

  20. New approach in paediatric dentistry: ultrasonic nondestructive evaluation of restorative dental materials. Experimental study. (United States)

    Ferrazzano, G F; Cantile, T; Coda, M; Ingenito, A


    The ultrasonic inspection is a non invasive method which is very developed in the industrial field, for the non-destructive evaluation of materials, and in the medical field, for the ultrasound diagnostic analysis. In paediatric dentistry the most widely used non- destructive evaluation is the X-ray technique. Radiographs are valuable aids in the oral health care of infants, children, adolescents, allowing dentists to diagnose and treat oral diseases that cannot be detected during a visual clinical examination. The aim of this in vitro study was to analyse the ultrasonic non-destructive evaluation (UT-NDE) technique to inspect both dental materials internal structure and the form and position of internal defects in order to obtain a diagnostic method, free of ionising radiations, in paediatric dentistry. Moreover the ultrasonic inspection (UT) could be a rapid method of diagnosis in uncooperative paediatric patients. Study Design: Experimental samples were manufactured with the characteristics of a large composite or glass ionomer cement paediatric dental restoration, in terms of either size or operative technique used. Characteristics of the common restorations were analysed and reproduced in vitro, using the same operative conditions, also adding operative defects into some samples. All the samples were subjected to an innovative UT test using the pulse echo immersion scanning technique. Both C-scans and full volume scans were carried out during the experimental programme. To enhance the data obtained from the UT scan, a digital system (Ecus Inspection software) for signal detection, archiving, processing and displaying was used. UT images showed the presence of internal defects in the dental materials. It was also possible to inspect very thin discontinuity such as the one represented by the fluid resin. In order to execute the statistical analysis, the values of electric voltage measured in five higher white points and in five higher grey points of the pictures

  1. Complex spatial dynamics of oncolytic viruses in vitro: mathematical and experimental approaches.

    Directory of Open Access Journals (Sweden)

    Dominik Wodarz

    Full Text Available Oncolytic viruses replicate selectively in tumor cells and can serve as targeted treatment agents. While promising results have been observed in clinical trials, consistent success of therapy remains elusive. The dynamics of virus spread through tumor cell populations has been studied both experimentally and computationally. However, a basic understanding of the principles underlying virus spread in spatially structured target cell populations has yet to be obtained. This paper studies such dynamics, using a newly constructed recombinant adenovirus type-5 (Ad5 that expresses enhanced jellyfish green fluorescent protein (EGFP, AdEGFPuci, and grows on human 293 embryonic kidney epithelial cells, allowing us to track cell numbers and spatial patterns over time. The cells are arranged in a two-dimensional setting and allow virus spread to occur only to target cells within the local neighborhood. Despite the simplicity of the setup, complex dynamics are observed. Experiments gave rise to three spatial patterns that we call "hollow ring structure", "filled ring structure", and "disperse pattern". An agent-based, stochastic computational model is used to simulate and interpret the experiments. The model can reproduce the experimentally observed patterns, and identifies key parameters that determine which pattern of virus growth arises. The model is further used to study the long-term outcome of the dynamics for the different growth patterns, and to investigate conditions under which the virus population eliminates the target cells. We find that both the filled ring structure and disperse pattern of initial expansion are indicative of treatment failure, where target cells persist in the long run. The hollow ring structure is associated with either target cell extinction or low-level persistence, both of which can be viewed as treatment success. Interestingly, it is found that equilibrium properties of ordinary differential equations describing the

  2. A Comparative Study of Collagen Matrix Density Effect on Endothelial Sprout Formation Using Experimental and Computational Approaches. (United States)

    Shamloo, Amir; Mohammadaliha, Negar; Heilshorn, Sarah C; Bauer, Amy L


    A thorough understanding of determining factors in angiogenesis is a necessary step to control the development of new blood vessels. Extracellular matrix density is known to have a significant influence on cellular behaviors and consequently can regulate vessel formation. The utilization of experimental platforms in combination with numerical models can be a powerful method to explore the mechanisms of new capillary sprout formation. In this study, using an integrative method, the interplay between the matrix density and angiogenesis was investigated. Owing the fact that the extracellular matrix density is a global parameter that can affect other parameters such as pore size, stiffness, cell-matrix adhesion and cross-linking, deeper understanding of the most important biomechanical or biochemical properties of the ECM causing changes in sprout morphogenesis is crucial. Here, we implemented both computational and experimental methods to analyze the mechanisms responsible for the influence of ECM density on the sprout formation that is difficult to be investigated comprehensively using each of these single methods. For this purpose, we first utilized an innovative approach to quantify the correspondence of the simulated collagen fibril density to the collagen density in the experimental part. Comparing the results of the experimental study and computational model led to some considerable achievements. First, we verified the results of the computational model using the experimental results. Then, we reported parameters such as the ratio of proliferating cells to migrating cells that was difficult to obtain from experimental study. Finally, this integrative system led to gain an understanding of the possible mechanisms responsible for the effect of ECM density on angiogenesis. The results showed that stable and long sprouts were observed at an intermediate collagen matrix density of 1.2 and 1.9 mg/ml due to a balance between the number of migrating and proliferating

  3. An experimental approach to the ecophysiology of the interstitial polychaete Polygordius eschaturus (Annelida: Polygordiidae

    Directory of Open Access Journals (Sweden)

    Lilia Pereira de Souza-Santos


    Full Text Available Specimens of Polygordius eschaturus from a reflective sandy beach were tested in the laboratory for tolerance to salinity and temperature and for their response to light, gravity and oxygen tension. After 192 h at 10°C, almost all specimens died at salinities of 10, 20 and 50 psu and were slow moving from 30 to 40. At 20°C and 30°C, all specimens died when salinity was 10; few showed abnormal behaviour at 50 and all presented normal behaviour from 20 to 40. At 40°C, all specimens died within 24 h. In our experimental conditions, the observed migration patterns corresponded to photonegative geopositive behaviours, but also indicated a positive response to a higher oxygen tension. These patterns, together with euryhalinity and eurythermy, are in accordance with the typical habitat of the species, from 10 to 20 cm depth in coarse sand above the swash zone. In the intertidal zone of the tropical beach where the worms were originally found, the combined behaviour leading to an attraction to well-oxygenated, dark subsurface sediment layers results in successful protection from the strong changes in salinity and temperature of the more superficial layers.


    Directory of Open Access Journals (Sweden)



    Full Text Available The objective of this paper is to investigate the effect of light sources on readability of students using psychophysical methods. Light sources such as Compact Fluorescent Lamp (CFL and Light Emitting Diode lamp (LED of same power rating were used in this research work because of their high lighting efficiency and uniformity of illuminance compared to that of Incandescent lamp (IL and florescent lamp (FL. A group of prospective students having normal vision, and abnormal vision like myopia, hypermetropia and astigmatism were involved in the test process. Three types of test like Snellen visual acuity, Color contrast test and Readability test were conducted on student participants under different lighting conditions. Test results showed the visibility and color contrast sensitivity of the students were high in the LED illumination. The quantitative measure of readability under different circumstances showed that the lightness difference on text under different color combination and font size, affected their readability. The computed average results confirmed that the luminance and color contrast were improved in LED illumination and also proved a high readability measure in the experimentation. Both the results of psychophysical test were proven that LED lighting was the best lighting system suitable for color distinction and readability.

  5. Folklore therapeutic indigenous plants in periodontal disorders in India (review, experimental and clinical approach). (United States)

    Patel, V K; Venkatakrishna-Bhatt, H


    Though a number of plants and their parts are used for dental ailments among population in rural and urban areas of developing countries, in India however, the most common house-hold, road-side plants are mango (Mangifera indica), neem (Azadirachta indica; Melia azadirachta), ocimum (Ocimum basilicum), tea-dust (Camellia sinensis) and uncommonly murayya, i.e., currey leaf (Murayya koenigi) [Chopra et al. 1958, Kirtikar and Basu 1935, Nadakarni 1954, Satyavati 1984]. The leaves of these plants are folded and brushed (massage with teadust) against the teeth. Therefore, the present study is restricted only to the fleshy leaf extracts [Jindal et al. 1975] (except tea) of these plants inspite of certain limitations in the methodology and arbitrations in the microbial identification and isolation in the light of recent advances in folk dentistry. The investigation was carried out in two parts: 1) Experimental study: The efficacy of various dentifrices (commonly available in the market) and the potentiating effect of the leaf extract (LE) of the aforesaid indigenous plants when amalgamated with the tooth-paste against pathogens, were investigated. Further, the protection afforded by the said plant extracts (PE) over the conventional allopathic medicines on the human plaque cultures and gram negative bacteria from patients were studied. 2) Clinical study: The therapeutic effects of the said PE (individually) on clinical application among severely infected patients were examined.

  6. An experimental approach to the study of the rheology behaviour of synthetic bone calcium phosphate cements

    Energy Technology Data Exchange (ETDEWEB)

    Friberg, J.; Fernandez, E.; Sarda, S.; Nilsson, M.; Ginebra, M.P.; Planell, J.A. [Universidad Politecnica de Catalunya, Barcelona (Spain). Dept. of Materials Science and Metallurgical Engineering; Martinez, S. [Barcelona Univ. (Spain). Mineralogia i Recursos Minerals


    Calcium phosphate cements were developed to fit surgical needs in biomedical fields such as odontology or traumatology. Nowadays, a broad field of new applications have been found for this kind of materials. Drug delivery systems, tissue-engineering scaffolds and osteoporotic bone filling applications are some of the new fields that are being benefited with these materials. Looking at both, commercial and new experimental calcium phosphate cements it is found that {alpha}-tricalcium phosphate is the main reactive powder responsible for the setting and the hardening of the cement. Thus, it is important to know how {alpha}-tricalcium phosphate affects injectability of these cements. The aim of this study was to investigate the rheological behaviour of {alpha}-tricalcium phosphate slurries in order to know how the cement injectability should be modified. Factors such as liquid to powder ratio, particle size of the main reactive powder and the addition of dispersants have been considered. The results showed that viscosity decreased when particle size of reactant was increased and when liquid to powder ratio was increased. It was also found that a minimum of viscosity exists at an optimum value of the weight percentage of dispersant. (orig.)

  7. Lead distribution in soils impacted by a secondary lead smelter: Experimental and modelling approaches

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Arnaud R., E-mail: [GEGENAA, EA 3795, Université de Reims Champagne-Ardenne, SFR Condorcet FR CNRS 3417, 2 esplanade Roland Garros, 51100 Reims (France); Cancès, Benjamin; Ponthieu, Marie [GEGENAA, EA 3795, Université de Reims Champagne-Ardenne, SFR Condorcet FR CNRS 3417, 2 esplanade Roland Garros, 51100 Reims (France); Sobanska, Sophie [Laboratoire de Spectrochimie IR et Raman, UMR-CNRS 8516, Bât. C5 Université de Lille I, 59655 Villeneuve d' Ascq Cedex (France); Benedetti, Marc F. [Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, UMR 7154, CNRS, F-75005 Paris (France); Pourret, Olivier [HydrISE, Institut Polytechnique LaSalle Beauvais, FR-60000 Beauvais (France); Conreux, Alexandra; Calandra, Ivan; Martinet, Blandine; Morvan, Xavier; Gommeaux, Maxime; Marin, Béatrice [GEGENAA, EA 3795, Université de Reims Champagne-Ardenne, SFR Condorcet FR CNRS 3417, 2 esplanade Roland Garros, 51100 Reims (France)


    Smelting activities are one of the most common sources of trace elements in the environment. The aim of this study was to determine the lead distribution in upper horizons (0–5 and 5–10 cm) of acidic soils in the vicinity of a lead-acid battery recycling plant in northern France. The combination of chemical methods (sequential extractions), physical methods (Raman microspectroscopy and scanning electron microscopy with an energy dispersive spectrometer) and multi-surface complexation modelling enabled an assessment of the behaviour of Pb. Regardless of the studied soil, none of the Pb-bearing phases commonly identified in similarly polluted environments (e.g., anglesite) were observed. Lead was mainly associated with organic matter and manganese oxides. The association of Pb with these soil constituents can be interpreted as evidence of Pb redistribution in the studied soils following smelter particle deposition. - Highlights: • Lead behavior was studied in smelter impacted soils. • A combination of experimental methods and modelling was employed. • Pb was mainly associated with organic matter and to a lesser degree with Mn oxides. • Pb was redistributed in soils after smelter particle deposition.

  8. Revisiting Formability and Failure of AISI304 Sheets in SPIF: Experimental Approach and Numerical Validation

    Directory of Open Access Journals (Sweden)

    Gabriel Centeno


    Full Text Available Single Point Incremental Forming (SPIF is a flexible and economic manufacturing process with a strong potential for manufacturing small and medium batches of highly customized parts. Formability and failure in SPIF have been intensively discussed in recent years, especially because this process allows stable plastic deformation well above the conventional forming limits, as this enhanced formability is only achievable within a certain range of process parameters depending on the material type. This paper analyzes formability and failure of AISI304-H111 sheets deformed by SPIF compared to conventional testing conditions (including Nakazima and stretch-bending tests. With this purpose, experimental tests in SPIF and stretch-bending were carried out and a numerical model of SPIF is performed. The results allow the authors to establish the following contributions regarding SPIF: (i the setting of the limits of the formability enhancement when small tool diameters are used, (ii the evolution of the crack when failure is attained and (iii the determination of the conditions upon which necking is suppressed, leading directly to ductile fracture in SPIF.

  9. Using the Montessori approach for a clientele with cognitive impairments: a quasi-experimental study design. (United States)

    Giroux, Dominique; Robichaud, Line; Paradis, Martin


    The choice of activities responding to the needs of people with moderate to severe dementia is a growing concern for care providers trying to target the need for a feeling of self-accomplishment by adapting activities to the abilities of elderly patients. The activities created by Maria Montessori seem to be adaptable to this clientele. This study evaluates the short-term effects, as compared to regular activities offered in the milieu. This is a quasi-experimental study where each of the 14 participants was observed and filmed in two conditions: during Montessori activities, during regular activities, and one control condition (no activity). The results show that Montessori activities have a significant effect on affect and on participation in the activity. They support the hypothesis that when activities correspond to the needs and abilities of a person with dementia, these positive effects are also observed on behaviours. This study enabled its authors to corroborate the findings presented in the literature and to contribute additional elements on the positive effects of the use of Montessori activities and philosophy. Used with people with moderate to severe dementia these allow the satisfaction of their basic psychological needs, their well being, and hence, on their quality of life.

  10. Temperature fluctuations in a changing climate: an ensemble-based experimental approach. (United States)

    Vincze, Miklós; Borcia, Ion Dan; Harlander, Uwe


    There is an ongoing debate in the literature about whether the present global warming is increasing local and global temperature variability. The central methodological issues of this debate relate to the proper treatment of normalised temperature anomalies and trends in the studied time series which may be difficult to separate from time-evolving fluctuations. Some argue that temperature variability is indeed increasing globally, whereas others conclude it is decreasing or remains practically unchanged. Meanwhile, a consensus appears to emerge that local variability in certain regions (e.g. Western Europe and North America) has indeed been increasing in the past 40 years. Here we investigate the nature of connections between external forcing and climate variability conceptually by using a laboratory-scale minimal model of mid-latitude atmospheric thermal convection subject to continuously decreasing 'equator-to-pole' temperature contrast ΔT, mimicking climate change. The analysis of temperature records from an ensemble of experimental runs ('realisations') all driven by identical time-dependent external forcing reveals that the collective variability of the ensemble and that of individual realisations may be markedly different - a property to be considered when interpreting climate records.

  11. An experimental/computational approach for examining unconfined cohesive powder flow. (United States)

    Faqih, AbdulMobeen; Chaudhuri, Bodhisattwa; Alexander, Albert W; Davies, Clive; Muzzio, Fernando J; Silvina Tomassone, M


    This paper describes a new method to quantitatively measure the flow characteristics of unconfined cohesive powders in a rotating drum. Cohesion plays an important role, affecting flow properties/characteristics, mixing rates, and segregation tendencies. The method relies on measuring the change in center of mass of the powder bed as it avalanches in the vessel, using a load cell that is sampled continuously. Filtering and analysis of the signal is done using Fast-Fourier transform into the frequency domain, where noise is eliminated using signal processing methods. The filtered data is transformed back to the time domain by using an inverse Fast-Fourier transform to give quantitative information on the powder flow characteristics. In order to understand the nature of the forces controlling powder flow behavior, a computational model was developed to estimate the relationship between inter-particle cohesive strength and experimental measurements. A "flow index" generated by the method correlates well with the degree of bed expansion (dynamic dilation) of the cohesive powders. The flow index also predicts the dynamics of flow through hoppers. As the flow index increases it becomes increasingly difficult for the powder to flow through the hoppers.

  12. Polyamide Microparticles Containing Vitamin C by Interfacial Polymerization: An Approach by Design of Experimentation

    Directory of Open Access Journals (Sweden)

    Lionel Ripoll


    Full Text Available Vitamin C is widely use in cosmetics and pharmaceutics products for its active properties. However ascorbic acid shows unfavourable chemical instability such as oxidation leading to formulation problems. Therefore, carriers, such as micro- and nanoparticles, have been widely investigated as delivery systems for vitamin C to improve its beneficial effects in skin treatment. However, none of the previous studies have been able to produce microparticles with a high encapsulation entrapment of vitamin C. The aim of the present study is to use an experimental design to optimize the synthesis of polyamide microparticles for the delivery of ascorbic acid. The effect of four formulation parameters on microparticles properties (size and morphology, encapsulation efficiency and yield, release kinetics were investigated using a surface response design. Finally, we were able to obtain stable microparticles containing more than 65% of vitamin C. This result confirms the effectiveness of using design of experiments for the optimisation of microparticle formulation and supports the proposal of using them as candidate for the delivery of vitamin C in skin treatment.

  13. PredPsych: A toolbox for predictive machine learning-based approach in experimental psychology research. (United States)

    Koul, Atesh; Becchio, Cristina; Cavallo, Andrea


    Recent years have seen an increased interest in machine learning-based predictive methods for analyzing quantitative behavioral data in experimental psychology. While these methods can achieve relatively greater sensitivity compared to conventional univariate techniques, they still lack an established and accessible implementation. The aim of current work was to build an open-source R toolbox - "PredPsych" - that could make these methods readily available to all psychologists. PredPsych is a user-friendly, R toolbox based on machine-learning predictive algorithms. In this paper, we present the framework of PredPsych via the analysis of a recently published multiple-subject motion capture dataset. In addition, we discuss examples of possible research questions that can be addressed with the machine-learning algorithms implemented in PredPsych and cannot be easily addressed with univariate statistical analysis. We anticipate that PredPsych will be of use to researchers with limited programming experience not only in the field of psychology, but also in that of clinical neuroscience, enabling computational assessment of putative bio-behavioral markers for both prognosis and diagnosis.

  14. Experimental and predicted approaches for biomass gasification with enriched air-steam in a fluidised bed. (United States)

    Fu, Qirang; Huang, Yaji; Niu, Miaomiao; Yang, Gaoqiang; Shao, Zhiwei


    Thermo-chemical gasification of sawdust refuse-derived fuel was performed on a bench-scale fluidised bed gasifier with enriched air and steam as fluidising and oxidising agents. Dolomite as a natural mineral catalyst was used as bed material to reform tars and hydrocarbons. A series of experiments were carried out under typical operating conditions for gasification, as reported in the article. A modified equilibrium model, based on equilibrium constants, was developed to predict the gasification process. The sensitivity analysis of operating parameters, such as the fluidisation velocity, oxygen percentage of the enriched air and steam to biomass ratios on the produced gas composition, lower heating value, carbon conversion and cold gas efficiency was investigated. The results showed that the predicted syngas composition was in better agreement with the experimental data compared with the original equilibrium model. The higher fluidisation velocity enhanced gas-solid mixing, heat and mass transfers, and carbon fines elutriation, simultaneously. With the increase of oxygen percentage from 21% to 45%, the lower heating value of syngas increased from 5.52 MJ m(-3) to 7.75 MJ m(-3) and cold gas efficiency from 49.09% to 61.39%. The introduction of steam improved gas quality, but a higher steam to biomass ratio could decrease carbon conversion and gasification efficiency owing to a low steam temperature. The optimal value of steam to biomass ratio in this work was 1.0. © The Author(s) 2014.

  15. A novel multi-stage direct contact membrane distillation module: Design, experimental and theoretical approaches. (United States)

    Lee, Jung-Gil; Kim, Woo-Seung; Choi, June-Seok; Ghaffour, Noreddine; Kim, Young-Deuk


    An economic desalination system with a small scale and footprint for remote areas, which have a limited and inadequate water supply, insufficient water treatment and low infrastructure, is strongly demanded in the desalination markets. Here, a direct contact membrane distillation (DCMD) process has the simplest configuration and potentially the highest permeate flux among all of the possible MD processes. This process can also be easily instituted in a multi-stage manner for enhanced compactness, productivity, versatility and cost-effectiveness. In this study, an innovative, multi-stage, DCMD module under countercurrent-flow configuration is first designed and then investigate both theoretically and experimentally to identify its feasibility and operability for desalination application. Model predictions and measured data for mean permeate flux are compared and shown to be in good agreement. The effect of the number of module stages on the mean permeate flux, performance ratio and daily water production of the MDCMD system has been theoretically identified at inlet feed and permeate flow rates of 1.5 l/min and inlet feed and permeate temperatures of 70 °C and 25 °C, respectively. The daily water production of a three-stage DCMD module with a membrane area of 0.01 m2 at each stage is found to be 21.5 kg. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Impact of dietary selenium intake on cardiac health: experimental approaches and human studies. (United States)

    Tanguy, Stéphane; Grauzam, Stéphane; de Leiris, Joël; Boucher, François


    Selenium, a dietary trace mineral, essential for humans and animals, exerts its effects mainly through its incorporation into selenoproteins. Adequate selenium intake is needed to maximize the activity of selenoproteins, among which glutathione peroxidases have been shown to play a major role in cellular defense against oxidative stress initiated by excess reactive oxygen species. In humans, a low selenium status has been linked to increased risk of various diseases, including heart disease. The main objective of this review is to present current knowledge on the role of selenium in cardiac health. Experimental studies have shown that selenium may exert protective effects on cardiac tissue in animal models involving oxidative stress. Because of the narrow safety margin of this mineral, most interventional studies in humans have reported inconsistent findings. Major determinants of selenium status in humans are not well understood and several nondietary factors might be associated with reduced selenium status. In this review, we discuss recent studies regarding the role of selenoproteins in the cardiovascular system, the effect of dietary intake on selenium status, the impact of selenium status on cardiac health, and the cellular mechanisms that can be involved in the physiological and toxic effects of selenium. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Electroless formation of silver nanoaggregates: An experimental and molecular dynamics approach

    KAUST Repository

    Gentile, Francesco T.


    The ability to manipulate matter to create non-conventional structures is one of the key issues of material science. The understanding of assembling mechanism at the nanoscale allows us to engineer new nanomaterials, with physical properties intimately depending on their structure.This paper describes new strategies to obtain and characterise metal nanostructures via the combination of a top-down method, such as electron beam lithography, and a bottom-up technique, such as the chemical electroless deposition. We realised silver nanoparticle aggregates within well-defined patterned holes created by electron beam lithography on silicon substrates. The quality characteristics of the nanoaggregates were verified by using scanning electron microscopy and atomic force microscopy imaging. Moreover, we compared the experimental findings to molecular dynamics simulations of nanoparticles growth. We observed a very high dependence of the structure characteristics on the pattern nanowell aspect ratio. We found that high-quality metal nanostructures may be obtained in patterns with well aspect ratio close to one, corresponding to a maximum diameter of 50 nm, a limit above which the fabricated structures become less regular and discontinuous. When regular shapes and sizes are necessary, as in nanophotonics, these results suggest the pattern characteristics to obtain isolated, uniform and reproducible metal nanospheres. © 2014 Taylor & Francis.

  18. Neuromorphological and wiring pattern alterations effects on brain function: a mixed experimental and computational approach.

    Directory of Open Access Journals (Sweden)

    Linus Manubens-Gil


    In addition, the study of fixed intact brains (by means of the state of the art CLARITY technique brings us closer to biologically and medically relevant situations, allowing not only to confirm whether the functional links in neuronal cultures are also present in vivo, but also enabling the introduction of functional information (like behavioral studies and functional imaging and another layer of structural alterations such as brain region morphology, neuronal density, and long-range connectivity. Taking together the experimental information from these systems we want to feed self-developed computational models that allow us to understand what are the fundamental characteristics of the observed connectivity patterns and the impact of each of the alterations on neuronal network function. These models will also provide a framework able to account for the emergent properties that bridge the gap between spontaneous electrical activity arousal/transmission and higher order information processing and memory storage capacities in the brain. As an additional part of the project we are now working on the application of the clearing, labeling and imaging protocols to human biopsy samples. Our aim is to obtain neuronal architecture and connectivity information from focal cortical dysplasia microcircuits using samples from intractable temporal lobe epilepsy patients that undergo deep-brain electrode recording diagnosis and posterior surgical extraction of the tissue. Our computational models can allow us to discern the contributions of the observed abnormalities to neuronal hyperactivity and epileptic seizure generation.

  19. A novel multi-stage direct contact membrane distillation module: Design, experimental and theoretical approaches

    KAUST Repository

    Lee, Jung Gil


    An economic desalination system with a small scale and footprint for remote areas, which have a limited and inadequate water supply, insufficient water treatment and low infrastructure, is strongly demanded in the desalination markets. Here, a direct contact membrane distillation (DCMD) process has the simplest configuration and potentially the highest permeate flux among all of the possible MD processes. This process can also be easily instituted in a multi-stage manner for enhanced compactness, productivity, versatility and cost-effectiveness. In this study, an innovative, multi-stage, DCMD module under countercurrent-flow configuration is first designed and then investigate both theoretically and experimentally to identify its feasibility and operability for desalination application. Model predictions and measured data for mean permeate flux are compared and shown to be in good agreement. The effect of the number of module stages on the mean permeate flux, performance ratio and daily water production of the MDCMD system has been theoretically identified at inlet feed and permeate flow rates of 1.5 l/min and inlet feed and permeate temperatures of 70 °C and 25 °C, respectively. The daily water production of a three-stage DCMD module with a membrane area of 0.01 m2 at each stage is found to be 21.5 kg.

  20. Do Halophytes Really Require Salts for Their Growth and Development? An Experimental Approach

    Directory of Open Access Journals (Sweden)

    Marius Nicusor GRIGORE


    Full Text Available Halophytes are salt-tolerant plants found exclusively in habitats with high levels of soil salinity. It is generally assumed that salt stress is the most important limiting factor for plant growth in natural saline environments, and that halophytes have developed specific adaptations to elevated salinity which make them unfitted to grow in the absence of salt, thus explaining their distribution in nature. To address experimentally this question, two halophytic species (Inula crithmoides L. and Plantago crassifolia Forssk. and a maritime dune species (Medicago marina L. were grown in the greenhouse for several weeks in different substrates: peat, vegetable garden soil, saline soil and sand from maritime dunes. Measurements of growth parameters number of leaves, plant length, fresh and dry weights showed that all three species grew much better on the salt-free and nutrient-rich substrates, peat and garden soil, than on saline soil and dune sand. These results indicate that salts are not compulsorily required for development of halophytic species, and suggest that limitation of water and nutrients, rather than soil salinity per se, are the most important restrictive factors for plant growth in saline habitats. The distribution of halophytes in nature is probably dependent on their limited ability to compete with glycophytes in non-saline areas, while remaining highly competitive under environmental conditions stressful for non-tolerant species.

  1. Do Halophytes Really Require Salts for Their Growth and Development? An Experimental Approach

    Directory of Open Access Journals (Sweden)

    Marius Nicusor GRIGORE


    Full Text Available Halophytes are salt-tolerant plants found exclusively in habitats with high levels of soil salinity. It is generally assumed that salt stress is the most important limiting factor for plant growth in natural saline environments, and that halophytes have developed specific adaptations to elevated salinity which make them unfitted to grow in the absence of salt, thus explaining their distribution in nature. To address experimentally this question, two halophytic species (Inula crithmoides L. and Plantago crassifolia Forssk. and a maritime dune species (Medicago marina L. were grown in the greenhouse for several weeks in different substrates: peat, vegetable garden soil, saline soil and sand from maritime dunes. Measurements of growth parameters � number of leaves, plant length, fresh and dry weights � showed that all three species grew much better on the salt-free and nutrient-rich substrates, peat and garden soil, than on saline soil and dune sand. These results indicate that salts are not compulsorily required for development of halophytic species, and suggest that limitation of water and nutrients, rather than soil salinity per se, are the most important restrictive factors for plant growth in saline habitats. The distribution of halophytes in nature is probably dependent on their limited ability to compete with glycophytes in non-saline areas, while remaining highly competitive under environmental conditions stressful for non-tolerant species.

  2. Risk assessment of nitrate transport through subsurface layers and groundwater using experimental and modeling approach. (United States)

    Alslaibi, Tamer M; Abunada, Ziyad; Abu Amr, Salem S; Abustan, Ismail


    Landfills are one of the main point sources of groundwater pollution. This research mainly aims to assess the risk of nitrate [Formula: see text] transport from the unlined landfill to subsurface layers and groundwater using experimental results and the SESOIL model. Samples from 12 groundwater wells downstream of the landfill were collected and analyzed in 2008, 21 years after the landfill construction. The average [Formula: see text] concentration in the wells was 54 mg/L, slightly higher than the World Health Organization ([Formula: see text] 50 mg/L) standards. SESOIL model was used to predict the [Formula: see text] concentration at the bottom of the unsaturated zone. Results indicated that the current mean [Formula: see text] concentration at the bottom of the unsaturated zone is 75 mg/L. the model predicted that the level of NO 3 will increased up to 325 mg/L within 30 years. Accordingly, the [Formula: see text] concentration in groundwater wells near the landfill area is expected to gradually increase with time. Although the current risk associated with the [Formula: see text] level might not be harm to adults, however, it might pose severe risks to both adults and infants in the near future due to [Formula: see text] leaching. Urgent mitigation measures such as final cell cover (cap), lining system and vertical expansion should be considered at the landfill to protect the public health in the area.

  3. Effects of Tibolone on the Central Nervous System: Clinical and Experimental Approaches

    Directory of Open Access Journals (Sweden)

    Rodolfo Pinto-Almazán


    Full Text Available Hormone replacement therapy (HRT increases the risk of endometrial and breast cancer. A strategy to reduce this incidence is the use of tibolone (TIB. The aim of this paper was to address the effects of TIB on the central nervous system (CNS. For the present review, MEDLINE (via PubMed, LILACS (via BIREME, Ovid Global Health, SCOPUS, Scielo, and PsycINFO (ProQuest Research Library electronic databases were searched for the results of controlled clinical trials on peri- and postmenopausal women published from 1990 to September 2016. Also, this paper reviews experimental studies performed to analyze neuroprotective effects, cognitive deficits, neuroplasticity, oxidative stress, and stroke using TIB. Although there are few studies on the effect of this hormone in the CNS, it has been reported that TIB decreases lipid peroxidation levels and improves memory and learning. TIB has important neuroprotective effects that could prevent the risk of neurodegenerative diseases in postmenopausal women as well as the benefits of HRT in counteracting hot flashes, improving mood, and libido. Some reports have found that TIB delays cognitive impairment in various models of neuronal damage. It also modifies brain plasticity since it acts as an endocrine modulator regulating neurotransmitters, Tau phosphorylation, and decreasing neuronal death. Finally, its antioxidant effects have also been reported in different animal models.

  4. Integrated experimental platforms to study blast injuries: a bottom-up approach (United States)

    Bo, C.; Williams, A.; Rankin, S.; Proud, W. G.; Brown, K. A.


    We are developing experimental models of blast injury using data from live biological samples. An integrated research strategy is followed to study material and biological properties of cells, tissues and organs, that are subjected to dynamic and static pressures, relevant to those of battlefield blast. We have developed a confined Split Hopkinson Pressure Bar (SHPB) system, which allows cells, either in suspension or as a monolayer, to be subjected to compression waves with pressures on the order of a few MPa and durations of hundreds of microseconds. The chamber design enables recovery of biological samples for cellular and molecular analysis. The SHPB platform, coupled with Quasi-Static experiments, is used to determine stress-strain curves of soft biological tissues under compression at low, medium and high strain rates. Tissue samples are examined, using histological techniques, to study macro- and microscopic changes induced by compression waves. In addition, a shock tube enables application of single or multiple air blasts with pressures on the order of kPa and a few milliseconds duration; this platform was used for initial studies on mesenchymal stem cells responses to blast pressures.

  5. Effect of reinforcement on the cutting forces while machining metal matrix composites–An experimental approach

    Directory of Open Access Journals (Sweden)

    Ch. Shoba


    Full Text Available Hybrid metal matrix composites are of great interest for researchers in recent years, because of their attractive superior properties over traditional materials and single reinforced composites. The machinabilty of hybrid composites becomes vital for manufacturing industries. The need to study the influence of process parameters on the cutting forces in turning such hybrid composite under dry environment is essentially required. In the present study, the influence of machining parameters, e.g. cutting speed, feed and depth of cut on the cutting force components, namely feed force (Ff, cutting force (Fc, and radial force (Fd has been investigated. Investigations were performed on 0, 2, 4, 6 and 8 wt% Silicon carbide (SiC and rice husk ash (RHA reinforced composite specimens. A comparison was made between the reinforced and unreinforced composites. The results proved that all the cutting force components decrease with the increase in the weight percentage of the reinforcement: this was probably due to the dislocation densities generated from the thermal mismatch between the reinforcement and the matrix. Experimental evidence also showed that built-up edge (BUE is formed during machining of low percentage reinforced composites at high speed and high depth of cut. The formation of BUE was captured by SEM, therefore confirming the result. The decrease of cutting force components with lower cutting speed and higher feed and depth of cut was also highlighted. The related mechanisms are explained and presented.

  6. Exploiting Thread Parallelism for Ocean Modeling on Cray XC Supercomputers

    Energy Technology Data Exchange (ETDEWEB)

    Sarje, Abhinav [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Jacobsen, Douglas W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Williams, Samuel W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ringler, Todd [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Oliker, Leonid [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)


    The incorporation of increasing core counts in modern processors used to build state-of-the-art supercomputers is driving application development towards exploitation of thread parallelism, in addition to distributed memory parallelism, with the goal of delivering efficient high-performance codes. In this work we describe the exploitation of threading and our experiences with it with respect to a real-world ocean modeling application code, MPAS-Ocean. We present detailed performance analysis and comparisons of various approaches and configurations for threading on the Cray XC series supercomputers.

  7. Selberg zeta functions and transfer operators an experimental approach to singular perturbations

    CERN Document Server

    Fraczek, Markus Szymon


    This book presents a method for evaluating Selberg zeta functions via transfer operators for the full modular group and its congruence subgroups with characters. Studying zeros of Selberg zeta functions for character deformations allows us to access the discrete spectra and resonances of hyperbolic Laplacians under both singular and non-singular perturbations. Areas in which the theory has not yet been sufficiently developed, such as the spectral theory of transfer operators or the singular perturbation theory of hyperbolic Laplacians, will profit from the numerical experiments discussed in this book. Detailed descriptions of numerical approaches to the spectra and eigenfunctions of transfer operators and to computations of Selberg zeta functions will be of value to researchers active in analysis, while those researchers focusing more on numerical aspects will benefit from discussions of the analytic theory, in particular those concerning the transfer operator method and the spectral theory of hyperbolic spac...

  8. Improving efficiency of human pluripotent stem cell differentiation platforms using an integrated experimental and computational approach. (United States)

    Selekman, Joshua A; Das, Amritava; Grundl, Nicholas J; Palecek, Sean P


    Human pluripotent stem cells (hPSCs) have an unparalleled potential for tissue engineering applications including regenerative therapies and in vitro cell-based models for studying normal and diseased tissue morphogenesis, or drug and toxicological screens. While numerous hPSC differentiation methods have been developed to generate various somatic cell types, the potential of hPSC-based technologies is hinged on the ability to translate these established lab-scale differentiation systems to large-scale processes to meet the industrial and clinical demands for these somatic cell types. Here, we demonstrate a strategy for investigating the efficiency and scalability of hPSC differentiation platforms. Using two previously reported epithelial differentiation systems as models, we fit an ODE-based kinetic model to data representing dynamics of various cell subpopulations present in our culture. This fit was performed by estimating rate constants of each cell subpopulation's cell fate decisions (self-renewal, differentiation, death). Sensitivity analyses on predicted rate constants indicated which cell fate decisions had the greatest impact on overall epithelial cell yield in each differentiation process. In addition, we found that the final cell yield was limited by the self-renewal rate of either the progenitor state or the final differentiated state, depending on the differentiation protocol. Also, the relative impact of these cell fate decision rates was highly dependent on the maximum capacity of the cell culture system. Overall, we outline a novel approach for quantitative analysis of established laboratory-scale hPSC differentiation systems and this approach may ease development to produce large quantities of cells for tissue engineering applications. © 2013 Wiley Periodicals, Inc.

  9. An Approach to Experimental Design for the Computer Analysis of Complex Phenomenon (United States)

    Rutherford, Brian


    The ability to make credible system assessments, predictions and design decisions related to engineered systems and other complex phenomenon is key to a successful program for many large-scale investigations in government and industry. Recently, many of these large-scale analyses have turned to computational simulation to provide much of the required information. Addressing specific goals in the computer analysis of these complex phenomenon is often accomplished through the use of performance measures that are based on system response models. The response models are constructed using computer-generated responses together with physical test results where possible. They are often based on probabilistically defined inputs and generally require estimation of a set of response modeling parameters. As a consequence, the performance measures are themselves distributed quantities reflecting these variabilities and uncertainties. Uncertainty in the values of the performance measures leads to uncertainties in predicted performance and can cloud the decisions required of the analysis. A specific goal of this research has been to develop methodology that will reduce this uncertainty in an analysis environment where limited resources and system complexity together restrict the number of simulations that can be performed. An approach has been developed that is based on evaluation of the potential information provided for each "intelligently selected" candidate set of computer runs. Each candidate is evaluated by partitioning the performance measure uncertainty into two components - one component that could be explained through the additional computational simulation runs and a second that would remain uncertain. The portion explained is estimated using a probabilistic evaluation of likely results for the additional computational analyses based on what is currently known about the system. The set of runs indicating the largest potential reduction in uncertainty is then selected

  10. Stress transfer from pile group in saturated and unsaturated soil using theoretical and experimental approaches

    Directory of Open Access Journals (Sweden)

    al-Omari Raid R.


    Full Text Available Piles are often used in groups, and the behavior of pile groups under the applied loads is generally different from that of single pile due to the interaction of neighboring piles, therefore, one of the main objectives of this paper is to investigate the influence of pile group (bearing capacity, load transfer sharing for pile shaft and tip in comparison to that of single piles. Determination of the influence of load transfer from the pile group to the surrounding soil and the mechanism of this transfer with increasing the load increment on the tip and pile shaft for the soil in saturated and unsaturated state (when there is a negative pore water pressure. Different basic properties are used that is (S = 90%, γd = 15 kN / m3, S = 90%, γd = 17 kN / m3 and S = 60%, γd =15 kN / m3. Seven model piles were tested, these was: single pile (compression and pull out test, 2×1, 3×1, 2×2, 3×2 and 3×3 group. The stress was measured with 5 cm diameter soil pressure transducer positioned at a depth of 5 cm below the pile tip for all pile groups. The measured stresses below the pile tip using a soil pressure transducer positioned at a depth of 0.25L (where L is the pile length below the pile tip are compared with those calculated using theoretical and conventional approaches. These methods are: the conventional 2V:1H method and the method used the theory of elasticity. The results showed that the method of measuring the soil stresses with soil pressure transducer adopted in this study, gives in general, good results of stress transfer compared with the results obtained from the theoretical and conventional approaches.

  11. The Open Lung Approach Improves Pulmonary Vascular Mechanics in an Experimental Model of Acute Respiratory Distress Syndrome. (United States)

    Santos, Arnoldo; Lucchetta, Luca; Monge-Garcia, M Ignacio; Borges, Joao Batista; Tusman, Gerardo; Hedenstierna, Goran; Larsson, Anders; Suarez-Sipmann, Fernando


    To test whether positive end-expiratory pressure consistent with an open lung approach improves pulmonary vascular mechanics compared with higher or lower positive end-expiratory pressures in experimental acute respiratory distress syndrome. Experimental study. Animal research laboratory. Ten pigs, 35 ± 5.2 kg. Acute respiratory distress syndrome was induced combining saline lung lavages with injurious mechanical ventilation. The positive end-expiratory pressure level resulting in highest compliance during a decremental positive end-expiratory pressure trial after lung recruitment was determined. Thereafter, three positive end-expiratory pressure levels were applied in a random order: hyperinflation, 6 cm H2O above; open lung approach, 2 cm H2O above; and collapse, 6 cm H2O below the highest compliance level. High fidelity pressure and flow sensors were placed at the main pulmonary artery for measuring pulmonary artery resistance (Z0), effective arterial elastance, compliance, and reflected pressure waves. After inducing acute respiratory distress syndrome, Z0 and effective arterial elastance increased (from 218 ± 94 to 444 ± 115 and from 0.27 ± 0.14 to 0.62 ± 0.22 mm Hg/mL, respectively; p mechanics compared with higher or lower positive end-expiratory pressure settings.

  12. Understanding small biomolecule-biomaterial interactions: a review of fundamental theoretical and experimental approaches for biomolecule interactions with inorganic surfaces. (United States)

    Costa, Dominique; Garrain, Pierre-Alain; Baaden, Marc


    Interactions between biomolecules and inorganic surfaces play an important role in natural environments and in industry, including a wide variety of conditions: marine environment, ship hulls (fouling), water treatment, heat exchange, membrane separation, soils, mineral particles at the earth's surface, hospitals (hygiene), art and buildings (degradation and biocorrosion), paper industry (fouling) and more. To better control the first steps leading to adsorption of a biomolecule on an inorganic surface, it is mandatory to understand the adsorption mechanisms of biomolecules of several sizes at the atomic scale, that is, the nature of the chemical interaction between the biomolecule and the surface and the resulting biomolecule conformations once adsorbed at the surface. This remains a challenging and unsolved problem. Here, we review the state of art in experimental and theoretical approaches. We focus on metallic biomaterial surfaces such as TiO(2) and stainless steel, mentioning some remarkable results on hydroxyapatite. Experimental techniques include atomic force microscopy, surface plasmon resonance, quartz crystal microbalance, X-ray photoelectron spectroscopy, fluorescence microscopy, polarization modulation infrared reflection absorption spectroscopy, sum frequency generation and time of flight secondary ion mass spectroscopy. Theoretical models range from detailed quantum mechanical representations to classical forcefield-based approaches. Copyright © 2012 Wiley Periodicals, Inc.

  13. An experimental approach to estimation of human information processing capacity for diagnosis tasks in NPPs

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Tae


    The objectives of this research are 1) to determine the human's information processing capacity and 2) to describe the relationship between the information processing capacity and human factors. This research centers on the relationship, as experimentally determined, between an operator's mental workload and information flow during accident diagnosis tasks at nuclear power plants (NPPs). The relationship between the information flow rate and operator's mental workload is investigated experimentally. According to this relationship, the operator's information processing capacity can be established. Once the information processing capacity of a main control room (MCR) operator in a NPP is known, it is possible to apply it 1) to predict the operator's performance, 2) to design diagnosis tasks, and 3) to design human-machine interface. In advanced MCR, an operator's mental activity is more important than his or her physical activity. The mental workload is the portion of the operator's limited capacity that is actually required to perform a particular task. A high mental workload may cause an operator to make a mistake and consequently affect that the safe operation of NPPs. Thus, to predict an operator's performance is very important for the nuclear safety. The information processing capacity is the operator's ability to manage the amount of bits per second when an operator is diagnosing tasks or accidents. We can estimate the information processing capacity using the relationship between the information flow rate and human performance. That is, if the operator's performance decreases rapidly as the information flow rate (bit/sec) is increased, it is possible to determine the operator's information processing capacity. A diagnosis task is one of the most complex and mentally demanding tasks as well as a crucial part in maintaining the safe operation of NPPs. Diagnosis tasks refer to the overall tasks of finding the

  14. Does Improved Water Access Increase Child School Attendance? A Quasi-Experimental Approach From Rural Ethiopia (United States)

    Masuda, Y.; Cook, J.


    This paper analyzes the impact of improved water access on child school attendance using two years of primary panel data from a quasi-experimental study in Oromiya, Ethiopia. A predominant form of child labor in rural poor households in least developed countries is water collection. Girls are often the primary water collectors for households, and because of the time intensive nature of water collection improved water access may allow for time to be reallocated to schooling (Rosen and Vincent 1999; Nankhuni and Findeis 2004). Understanding how improved water access may increase schooling for girls has important development policy implications. Indeed, abundant research on returns to education suggests increased schooling for girls is tied to improved future child and maternal health, economic opportunities, and lower fertility rates (Handa 1996; Schultz 1998; Michaelowa 2000). The literature to date finds that improved water access leads to increased schooling; however, there still exists a clear gap in the literature for understanding this relationship for two reasons. First, only four studies have directly examined the relationship between improved water access and schooling in sub-Saharan Africa, and analyses have been limited due to the use of cross-sectional data and research designs (Nankhuni and Findeis 2004; Koolwal and Van de Walle 2010; Ndiritu and Nyangan 2011; Nauges and Strand 2011). Indeed, only two studies have attempted to control for the endogenous nature of water access. Second, all studies use a binary school enrollment indicator from household surveys, which may suffer from response bias and may be an imperfect measure for actual schooling. Respondents may feel pressured to report that their children are enrolled in school if, like in Ethiopia, there are compulsory education laws. This may result in an overestimation of school enrollment. In addition, most children from rural poor households combine work and school, and a binary indicator does

  15. Determination of equivalent breast phantoms for different age groups of Taiwanese women: An experimental approach

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Shang-Lung; Chu, Tieh-Chi; Lin, Yung-Chien; Lan, Gong-Yau; Yeh, Yu-Hsiu; Chen, Sharon; Chuang, Keh-Shih [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 101 Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Department of Radiology, Cheng Hsin General Hospital, 45 Cheng Hsin Street, Pai-Tou District, Taipei 11220, Taiwan (China); Department of Medical Imaging and Radiological Sciences, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 80708, Taiwan (China); Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 101 Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China)


    Purpose: Polymethylmethacrylate (PMMA) slab is one of the mostly used phantoms for studying breast dosimetry in mammography. The purpose of this study was to evaluate the equivalence between exposure factors acquired from PMMA slabs and patient cases of different age groups of Taiwanese women in mammography. Methods: This study included 3910 craniocaudal screen/film mammograms on Taiwanese women acquired on one mammographic unit. The tube loading, compressed breast thickness (CBT), compression force, tube voltage, and target/filter combination for each mammogram were collected for all patients. The glandularity and the equivalent thickness of PMMA were determined for each breast using the exposure factors of the breast in combination with experimental measurements from breast-tissue-equivalent attenuation slabs. Equivalent thicknesses of PMMA to the breasts of Taiwanese women were then estimated. Results: The average {+-} standard deviation CBT and breast glandularity in this study were 4.2 {+-} 1.0 cm and 54% {+-} 23%, respectively. The average equivalent PMMA thickness was 4.0 {+-} 0.7 cm. PMMA slabs producing equivalent exposure factors as in the breasts of Taiwanese women were determined for the age groups 30-49 yr and 50-69 yr. For the 4-cm PMMA slab, the CBT and glandularity values of the equivalent breast were 4.1 cm and 65%, respectively, for the age group 30-49 yr and 4.4 cm and 44%, respectively, for the age group 50-69 yr. Conclusions: The average thickness of PMMA slabs producing the same exposure factors as observed in a large group of Taiwanese women is less than that reported for American women. The results from this study can provide useful information for determining a suitable thickness of PMMA for mammographic dose survey in Taiwan. The equivalence of PMMA slabs and the breasts of Taiwanese women is provided to allow average glandular dose assessment in clinical practice.

  16. Characterization and intramolecular bonding patterns of busulfan: Experimental and quantum chemical approach (United States)

    Karthick, T.; Tandon, Poonam; Singh, Swapnil; Agarwal, Parag; Srivastava, Anubha


    The investigations of structural conformers, molecular interactions and vibrational characterization of pharmaceutical drug are helpful to understand their behaviour. In the present work, the 2D potential energy surface (PES) scan has been performed on the dihedral angles C6sbnd O4sbnd S1sbnd C5 and C25sbnd S22sbnd O19sbnd C16 to find the stable conformers of busulfan. In order to show the effects of long range interactions, the structures on the global minima of PES scan have been further optimized by B3LYP/6-311 ++G(d,p) method with and without empirical dispersion functional in Gaussian 09W package. The presence of n → σ* and σ → σ* interactions which lead to stability of the molecule have been predicted by natural bond orbital analysis. The strong and weak hydrogen bonds between the functional groups of busulfan were analyzed using quantum topological atoms in molecules analysis. In order to study the long-range forces, such as van der Waals interactions, steric effect in busulfan, the reduced density gradient as well as isosurface defining these interactions has been plotted using Multiwfn software. The spectroscopic characterization on the solid phase of busulfan has been studied by experimental FT-IR and FT-Raman spectra. From the 13C and 1H NMR spectra, the chemical shifts of individual C and H atoms of busulfan have been predicted. The maximum absorption wavelengths corresponding to the electronic transitions between the highest occupied molecular orbital and the lowest unoccupied molecular orbital of busulfan have been found by UV-vis spectrum.

  17. A transverse oscillation approach for estimation of three-dimensional velocity vectors, part II: experimental validation. (United States)

    Pihl, Michael Johannes; Stuart, Matthias Bo; Tomov, Borislav Gueorguiev; Rasmussen, Morten Fischer; Jensen, Jørgen Arendt


    The 3-D transverse oscillation method is investigated by estimating 3-D velocities in an experimental flow-rig system. Measurements of the synthesized transverse oscillating fields are presented as well. The method employs a 2-D transducer; decouples the velocity estimation; and estimates the axial, transverse, and elevation velocity components simultaneously. Data are acquired using a research ultrasound scanner. The velocity measurements are conducted with steady flow in sixteen different directions. For a specific flow direction with [α, ß] = [45, 15]°, the mean estimated velocity vector at the center of the vessel is (v(x), v(y), v(z)) = (33.8, 34.5, 15.2) ± (4.6, 5.0, 0.6) cm/s where the expected velocity is (34.2, 34.2, 13.0) cm/s. The velocity magnitude is 50.6 ± 5.2 cm/s with a bias of 0.7 cm/s. The flow angles α and ß are estimated as 45.6 ± 4.9° and 17.6 ± 1.0°. Subsequently, the precision and accuracy are calculated over the entire velocity profiles. On average for all direction, the relative mean bias of the velocity magnitude is -0.08%. For α and ß, the mean bias is -0.2° and -1.5°. The relative standard deviations of the velocity magnitude ranges from 8 to 16%. For the flow angles, the ranges of the mean angular deviations are 5° to 16° and 0.7° and 8°.

  18. An XAS experimental approach to study low Pt content electrocatalysts operating in PEM fuel cells. (United States)

    Principi, Emiliano; Witkowska, Agnieszka; Dsoke, Sonia; Marassi, Roberto; Di Cicco, Andrea


    We present an X-ray absorption spectroscopy (XAS) study of a low Pt content catalyst layer (Pt loading 0.1 mg cm(-2)) operating at the cathode of a proton exchange membrane fuel cell (PEMFC). This catalyst is based on the use of a mesoporous inorganic matrix as a support for the catalyst Pt nanoparticles. Due to the high Pt dilution, in situ measurements of its structural properties by XAS are challenging and suitable experimental strategies must be devised for this purpose. In particular, we show that accurate XAS in situ fluorescence measurements can be obtained using an optimized fuel cell, suitable protocols for alignment of a focused X-ray beam and an appropriate filter for the background signal of the other atomic species contained in the electrodes. Details, advantages and limitations of the XAS technique for in situ measurements are discussed. Analysis of the near-edge XAS and EXAFS (extended X-ray absorption fine structure) data, corroborated by a HRTEM (high-resolution transmission electron microscopy) study, shows that the Pt particles have a local structure compatible with that of bulk Pt (fcc) and coordination numbers match those expected for particles with typical sizes in the 1.5-2.0 nm range. Substantial changes in the oxidation state and in local atomic arrangement of the Pt particles are found for different applied potentials. The catalyst support, containing W atoms, exhibits a partial reduction upon PEMFC activation, thus mimicking the catalyst behavior. This indicates a possible role of the mesoporous matrix in favouring the oxygen reduction reaction (ORR) and stimulates further research on active catalyst supports.

  19. Characterization and intramolecular bonding patterns of busulfan: Experimental and quantum chemical approach. (United States)

    Karthick, T; Tandon, Poonam; Singh, Swapnil; Agarwal, Parag; Srivastava, Anubha


    The investigations of structural conformers, molecular interactions and vibrational characterization of pharmaceutical drug are helpful to understand their behaviour. In the present work, the 2D potential energy surface (PES) scan has been performed on the dihedral angles C6O4S1C5 and C25S22O19C16 to find the stable conformers of busulfan. In order to show the effects of long range interactions, the structures on the global minima of PES scan have been further optimized by B3LYP/6-311++G(d,p) method with and without empirical dispersion functional in Gaussian 09W package. The presence of n→σ* and σ→σ* interactions which lead to stability of the molecule have been predicted by natural bond orbital analysis. The strong and weak hydrogen bonds between the functional groups of busulfan were analyzed using quantum topological atoms in molecules analysis. In order to study the long-range forces, such as van der Waals interactions, steric effect in busulfan, the reduced density gradient as well as isosurface defining these interactions has been plotted using Multiwfn software. The spectroscopic characterization on the solid phase of busulfan has been studied by experimental FT-IR and FT-Raman spectra. From the (13)C and (1)H NMR spectra, the chemical shifts of individual C and H atoms of busulfan have been predicted. The maximum absorption wavelengths corresponding to the electronic transitions between the highest occupied molecular orbital and the lowest unoccupied molecular orbital of busulfan have been found by UV-vis spectrum. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Invertebrate predation on egg masses of the European cuttlefish, Sepia officinalis: An experimental approach (United States)

    Martins, Catarina P. P.; Fernández-Álvarez, Fernando Á.; Villanueva, Roger


    The eggs of the European cuttlefish, Sepia officinalis, develop attached to the seafloor in shallow water habitats and possess a relatively thick black capsule that protects them from the surrounding environment. Since embryological development may take several months, eggs are vulnerable to a variety of threats present in shallow waters, including predation. This study investigates predation of S. officinalis eggs by benthic invertebrates. Twenty-eight invertebrate species from 6 different phyla and with diverse feeding habits were tested as potential predators under laboratory conditions. We also investigated how the feeding traits of these species are related to the mechanical ability to break the egg capsule and prey upon cuttlefish embryos. Species that fed on cuttlefish eggs were the sea snail Bolinus brandaris, the crab Cancer pagurus, the hermit crab Dardanus arrosor, the lobster Homarus gammarus, the invasive blue crab Callinectes sapidus, the shrimp Squilla mantis, the sea urchins Echinus melo, Cidaris sp. and Paracentrotus lividus and the starfish Astropecten aranciacus. It is of note that C. sapidus is a potential predatory crab, which raises the concern that this invasive species may constitute a novel threat for cuttlefish eggs as more populations become established in NE Atlantic waters. Of the biological traits examined, prey capture tools in the tested species best explained the experimental feeding results, suggesting that predation of S. officinalis eggs was determined generally by a mechanical factor and highlighting the importance of the protective egg capsule against predators. However, chemosensory factors are likely to be implicated as well. Thus, this work contributes to the understanding of the ecology of early life stages of cuttlefish and the factors that can affect offspring survival and subsequently impact the recruitment of this species.

  1. Chlorination and dechlorination rates in a forest soil — A combined modelling and experimental approach

    Energy Technology Data Exchange (ETDEWEB)

    Montelius, Malin, E-mail: [Department of Thematic Studies — Environmental Change, Linköping University, 581 83 Linköping (Sweden); Svensson, Teresia [Department of Thematic Studies — Environmental Change, Linköping University, 581 83 Linköping (Sweden); Lourino-Cabana, Beatriz [EDF, Laboratoire National d' Hydraulique et Environnement, 78401 Chatou (France); Thiry, Yves [Andra, Research and Development Division, Parc de la Croix Blanche, 1/7 rue Jean Monnet, 92298 Châtenay-Malabry Cedex (France); Bastviken, David [Department of Thematic Studies — Environmental Change, Linköping University, 581 83 Linköping (Sweden)


    Much of the total pool of chlorine (Cl) in soil consists of naturally produced organic chlorine (Cl{sub org}). The chlorination of bulk organic matter at substantial rates has been experimentally confirmed in various soil types. The subsequent fates of Cl{sub org} are important for ecosystem Cl cycling and residence times. As most previous research into dechlorination in soils has examined either single substances or specific groups of compounds, we lack information about overall bulk dechlorination rates. Here we assessed bulk organic matter chlorination and dechlorination rates in coniferous forest soil based on a radiotracer experiment conducted under various environmental conditions (additional water, labile organic matter, and ammonium nitrate). Experiment results were used to develop a model to estimate specific chlorination (i.e., fraction of Cl{sup −} transformed to Cl{sub org} per time unit) and specific dechlorination (i.e., fraction of Cl{sub org} transformed to Cl{sup −} per time unit) rates. The results indicate that chlorination and dechlorination occurred simultaneously under all tested environmental conditions. Specific chlorination rates ranged from 0.0005 to 0.01 d{sup −1} and were hampered by nitrogen fertilization but were otherwise similar among the treatments. Specific dechlorination rates were 0.01–0.03 d{sup −1} and were similar among all treatments. This study finds that soil Cl{sub org} levels result from a dynamic equilibrium between the chlorination and rapid dechlorination of some Cl{sub org} compounds, while another Cl{sub org} pool is dechlorinated more slowly. Altogether, this study demonstrates a highly active Cl cycling in soils. - Highlights: • Chlorination and dechlorination rates in soil were revealed by a radiotracer method. • Chlorination was hampered by nitrogen addition. • Both Cl{sup −} and many Cl{sub org} compounds are highly reactive in soils. • Some formed Cl{sub org} seem to be refractory.

  2. Early-Life Effects on Adult Physical Activity: Concepts, Relevance, and Experimental Approaches. (United States)

    Garland, Theodore; Cadney, Marcell D; Waterland, Robert A

    Locomotion is a defining characteristic of animal life and plays a crucial role in most behaviors. Locomotion involves physical activity, which can have far-reaching effects on physiology and neurobiology, both acutely and chronically. In human populations and in laboratory rodents, higher levels of physical activity are generally associated with positive health outcomes, although excessive exercise can have adverse consequences. Whether and how such relationships occur in wild animals is unknown. Behavioral variation among individuals arises from genetic and environmental factors and their interactions as well as from developmental programming (persistent effects of early-life environment). Although tremendous progress has been made in identifying genetic and environmental influences on individual differences in behavior, early-life effects are not well understood. Early-life effects can in some cases persist across multiple generations following a single exposure and, in principle, may constrain or facilitate the rate of evolution at multiple levels of biological organization. Understanding the mechanisms of such transgenerational effects (e.g., exposure to stress hormones in utero, inherited epigenetic alterations) may prove crucial to explaining unexpected and/or sex-specific responses to selection as well as limits to adaptation. One area receiving increased attention is early-life effects on adult physical activity. Correlational data from epidemiological studies suggest that early-life nutritional stress can (adversely) affect adult human activity levels and associated physiological traits (e.g., body composition, metabolic health). The few existing studies of laboratory rodents demonstrate that both maternal and early-life exercise can affect adult levels of physical activity and related phenotypes. Going forward, rodents offer many opportunities for experimental studies of (multigenerational) early-life effects, including studies that use maternal

  3. A cool experimental approach to explain elevational treelines, but can it explain them? (United States)

    Bader, Maaike Y; Loranger, Hannah; Zotz, Gerhard


    At alpine treeline, trees give way to low-stature alpine vegetation. The main reason may be that tree canopies warm up less in the sun and experience lower average temperatures than alpine vegetation. Low growth temperatures limit tissue formation more than carbon gain, but whether this mechanism universally determines potential treeline elevations is the subject of debate. To study low-temperature limitation in two contrasting treeline tree species, Fajardo and Piper (American Journal of Botany 101: 788-795) grew potted seedlings at ground level or suspended at tree-canopy height (2 m), introducing a promising experimental method for studying the effects of alpine-vegetation and tree-canopy microclimates on tree growth. On the basis of this experiment, the authors concluded that lower temperatures at 2 m caused carbon limitation in one of the species and that treeline-forming mechanisms may thus be taxon-dependent. Here we contest that this important conclusion can be drawn based on the presented experiment, because of confounding effects of extreme root-zone temperature fluctuations and potential drought conditions. To interpret the results of this elegant experiment without logistically challenging technical modifications and to better understand how low temperature leads to treeline formation, studies on effects of fluctuating vs. stable temperatures are badly needed. Other treeline research priorities are interactions between temperature and other climatic factors and differences in microclimate between tree canopies with contrasting morphology and physiology. In spite of our criticism of this particular study, we agree that the development of a universal treeline theory should include continuing explorations of taxon-specific treeline-forming mechanisms. © 2014 Botanical Society of America, Inc.

  4. The Gaia scientific exploitation networks (United States)

    Figueras, F.; Jordi, C.


    On July 2014 the Gaia satellite, placed at L2 since January 2014, finished their commissioning phase and started collecting high accurate scientific data. New and more realistic estimations of the astrometric, photometric and spectroscopic accuracy expected after five years mission operation (2014-2019) have been recently published in the Gaia Science Performance Web page. Here we present the coordination efforts and the activities being conducted through the two GREAT (Gaia Research for European Astronomy Training) European Networks, the GREAT-ESF, a programme supported by the European Science Foundation (2010-2015), and the GREAT-ITN network, from the European Union's Seventh Framework Programme (2011-2015). The main research theme of these networks is to unravel the origin and history of our home galaxy. Emphasis is placed on the research projects being conducted by the Spanish Researchers through these networks, well coordinated by the Red Española de Explotación Científica de Gaia (REG network, with more than 140 participants). Members of the REG play an important role on the collection of complementary spectroscopic data from ground based telescopes, on the development of new tools for an optimal scientific exploitation of Gaia data and on the preparation task to create the Gaia archive.

  5. A New Two-Step Approach for Hands-On Teaching of Gene Technology: Effects on Students' Activities During Experimentation in an Outreach Gene Technology Lab (United States)

    Scharfenberg, Franz-Josef; Bogner, Franz X.


    Emphasis on improving higher level biology education continues. A new two-step approach to the experimental phases within an outreach gene technology lab, derived from cognitive load theory, is presented. We compared our approach using a quasi-experimental design with the conventional one-step mode. The difference consisted of additional focused discussions combined with students writing down their ideas (step one) prior to starting any experimental procedure (step two). We monitored students' activities during the experimental phases by continuously videotaping 20 work groups within each approach ( N = 131). Subsequent classification of students' activities yielded 10 categories (with well-fitting intra- and inter-observer scores with respect to reliability). Based on the students' individual time budgets, we evaluated students' roles during experimentation from their prevalent activities (by independently using two cluster analysis methods). Independently of the approach, two common clusters emerged, which we labeled as `all-rounders' and as `passive students', and two clusters specific to each approach: `observers' as well as `high-experimenters' were identified only within the one-step approach whereas under the two-step conditions `managers' and `scribes' were identified. Potential changes in group-leadership style during experimentation are discussed, and conclusions for optimizing science teaching are drawn.

  6. Predicting Transport of 3,5,6-Trichloro-2-Pyridinol Into Saliva Using a Combination Experimental and Computational Approach

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Jordan Ned; Carver, Zana A.; Weber, Thomas J.; Timchalk, Charles


    A combination experimental and computational approach was developed to predict chemical transport into saliva. A serous-acinar chemical transport assay was established to measure chemical transport with non-physiological (standard cell culture medium) and physiological (using surrogate plasma and saliva medium) conditions using 3,5,6-trichloro-2-pyridinol (TCPy) a metabolite of the pesticide chlorpyrifos. High levels of TCPy protein binding was observed in cell culture medium and rat plasma resulting in different TCPy transport behaviors in the two experimental conditions. In the non-physiological transport experiment, TCPy reached equilibrium at equivalent concentrations in apical and basolateral chambers. At higher TCPy doses, increased unbound TCPy was observed, and TCPy concentrations in apical and basolateral chambers reached equilibrium faster than lower doses, suggesting only unbound TCPy is able to cross the cellular monolayer. In the physiological experiment, TCPy transport was slower than non-physiological conditions, and equilibrium was achieved at different concentrations in apical and basolateral chambers at a comparable ratio (0.034) to what was previously measured in rats dosed with TCPy (saliva:blood ratio: 0.049). A cellular transport computational model was developed based on TCPy protein binding kinetics and accurately simulated all transport experiments using different permeability coefficients for the two experimental conditions (1.4 vs 0.4 cm/hr for non-physiological and physiological experiments, respectively). The computational model was integrated into a physiologically based pharmacokinetic (PBPK) model and accurately predicted TCPy concentrations in saliva of rats dosed with TCPy. Overall, this study demonstrates an approach to predict chemical transport in saliva potentially increasing the utility of salivary biomonitoring in the future.

  7. Quantifying Aeolian Flow-Landform Interactions Using Novel Lab-Scale Experimental Approaches (United States)

    Christensen, K. T.; Bristow, N.; Hamed, A. M.; Kim, T.; Blois, G.; Best, J.


    Aeolian transport processes are driven by coupled interactions of flow with complex and dynamic topography. The complexity of this coupling inhibits predictions of sediment transport, landscape morphodynamics and concomitant biophysical and geochemical processes. Many of these flows occur in conditions and/or at scales that limit or completely impede access via modern flow diagnostics due to geometry and/or coexistence of multiple phases. Given the broad range of scales of such flows, modeling at small scales is required to enable predictive simulations. It is at these scales where experiments can inform model development that accurately reflect the physics of such processes to yield reliable system-scale predictions. This lecture will highlight specific two laboratory studies: turbulent flow associated with interacting barchan dunes and the flow overlying a model crater representative of that observed on Mars. The evolution of and dynamics associated with barchan dunes involve a strong degree of coupling between sediment transport, morphological change, and flow, the last of which represents the weakest link in our understanding of barchan morphodynamics. Newly available morphological data from high-resolution images from orbiting NASA spacecraft, complemented by on-site observations, is supporting the paleoscientific reconstruction of Mars environmental conditions. Central to this goal is understanding the geomorphology of Mars craters, including morphological processes that control their evolution for those that host a central mound. The 3D nature of both landforms presents challenges for measuring the full flow field. We therefore utilize a novel refractive index matching (RIM) approach coupled with particle-image velocimetry (PIV) methods to fully interrogate the flow around fixed barchan dune models in tandem and a crater model formed from a DEM of Gale Crater. The barchan and crater models were fabricated from acrylic whose refractive index matches the

  8. Modeling of Bioaccumulation in Marine Benthic Invertebrates Using a Multispecies Experimental Approach. (United States)

    Diepens, Noël J; Van den Heuvel-Greve, Martine J; Koelmans, Albert A


    The causal links between species traits and bioaccumulation by marine invertebrates are poorly understood. We assessed these links by measuring and modeling polychlorinated biphenyl bioaccumulation by four marine benthic species. Uniformity of exposure was achieved by testing each species in the same aquarium, separated by enclosures, to ensure that the observed variability in bioaccumulation was due to species traits. The relative importance of chemical uptake from pore water or food (organic matter, OM) ingestion was manipulated by using artificial sediment with different OM contents. Biota sediment accumulation factors (BSAFs) ranged from 5 to 318, in the order Nereis virens < Arenicola marina ≈ Macoma balthica < Corophium volutator. Calibration of a kinetic model provided species-specific parameters that represented the key species traits, thus illustrating how models provide an opportunity to read across benthic species with different feeding strategies. Key traits included species-specific differentiation between (1) ingestion rates, (2) ingestion of suspended and settled OM, and (3) elimination rates. The high BSAF values and their concomitant variability across the species challenges approaches for exposure assessment based on pore water concentration analysis and equilibrium partition theory. We propose that combining multienclosure testing and modeling will substantially improve exposure assessment in sediment toxicity tests.

  9. Identification and Induction of Human, Social, and Cultural Capitals through an Experimental Approach to Stormwater Management

    Directory of Open Access Journals (Sweden)

    Hale W. Thurston


    Full Text Available Decentralized stormwater management is based on the dispersal of stormwater management practices (SWMP throughout a watershed to manage stormwater runoff volume and potentially restore natural hydrologic processes. This approach to stormwater management is increasingly popular but faces constraints related to land access and citizen engagement. We tested a novel method of environmental management through citizen-based stormwater management on suburban private land. After a nominal induction of human capital through an education campaign, two successive (2007, 2008 reverse auctions engaged residents to voluntarily bid on installation of SWMPs on their property. Cumulatively, 81 rain gardens and 165 rain barrels were installed on approximately one-third of the 350 eligible residential properties in the watershed, resulting in an estimated 360 m3 increase in stormwater detention capacity. One surprising result was the abundance of zero dollar bids, indicating even a limited-effort human capital campaign was sufficient to enroll many participants. In addition, we used statistical methods to illustrate the significant role of social capital in forming clusters of adjacent properties that participated in bidding. This indicated that as participants shared their experiences, neighbors may have become more willing to trust the program and enroll. Significant agglomerations of participating properties may indicate a shift in neighborhood culture regarding stormwater management with positive implications for watershed health through the sustained induction of alternate capitals.

  10. An experimental design approach to the optimisation of a flow injection analysis method for glycine. (United States)

    Vannecke, C; Baré, S; Bloomfield, M; Massart, D L


    A flow injection analysis method for the determination of glycine, based on the reaction with ortho-phtalaldehyde and N-acetylcysteine in a basic buffer, was optimised. In the first step screening of the variables, to select the most important ones, was performed using: (i) a half-fraction factorial design and (ii) a quarter-fraction factorial design, for five factors at two levels. The effects of the factors on the peak height were calculated from both screening designs and compared. For the half-fraction factorial design (resolution IV), the significance of the factor effects on the peak height was checked by: (i) comparing them with a critical effect, calculated from two-factor interactions and based on a t-test, (ii) using a non parametric approach and (iii) drawing a normal probability plot. For the quarter-fraction factorial design (resolution III) the significance of the effects of the factors on the peak height was checked using: (i) a randomization test method, (ii) the non parametric method and (iii) a normal probability plot. In the second step, the factor found to be of importance was optimised using the uniplex method.

  11. "Teamwork in hospitals": a quasi-experimental study protocol applying a human factors approach. (United States)

    Ballangrud, Randi; Husebø, Sissel Eikeland; Aase, Karina; Aaberg, Oddveig Reiersdal; Vifladt, Anne; Berg, Geir Vegard; Hall-Lord, Marie Louise


    Effective teamwork and sufficient communication are critical components essential to patient safety in today's specialized and complex healthcare services. Team training is important for an improved efficiency in inter-professional teamwork within hospitals, however the scientific rigor of studies must be strengthen and more research is required to compare studies across samples, settings and countries. The aims of the study are to translate and validate teamwork questionnaires and investigate healthcare personnel's perception of teamwork in hospitals (Part 1). Further to explore the impact of an inter-professional teamwork intervention in a surgical ward on structure, process and outcome (Part 2). To address the aims, a descriptive, and explorative design (Part 1), and a quasi-experimental interventional design will be applied (Part 2). The study will be carried out in five different hospitals (A-E) in three hospital trusts in Norway. Frontline healthcare personnel in Hospitals A and B, from both acute and non-acute departments, will be invited to respond to three Norwegian translated teamwork questionnaires (Part 1). An inter-professional teamwork intervention in line with the TeamSTEPPS recommend Model of Change will be implemented in a surgical ward at Hospital C. All physicians, registered nurses and assistant nurses in the intervention ward and two control wards (Hospitals D and E) will be invited to to survey their perception of teamwork, team decision making, safety culture and attitude towards teamwork before intervention and after six and 12 months. Adult patients admitted to the intervention surgical unit will be invited to survey their perception of quality of care during their hospital stay before intervention and after six and 12 month. Moreover, anonymous patient registry data from local registers and data from patients' medical records will be collected (Part 2). This study will help to understand the impact of an inter-professional teamwork

  12. Constraints on the Dynamics of Seabed Pockmarks: an Integrated Sedimentological, Biostratigraphic, Geophysical, Oceanographic and Experimental Approach (United States)

    Pau, M.; Hammer, Ø.; Chand, S.; Gisler, G. R.


    Pockmarks are crater-like seabed depressions commonly resulting from focused fluid escape from soft, fine-grained sediments. Typically measuring 20-50 m across with depths of 2-10 m, these features often occur in extensive fields containing hundreds of them per square kilometre. They are prominent hazards for offshore installations such as oil rigs and pipelines, affecting vast areas worldwide. Besides, they represent a major geological source of methane, and their importance has been pointed out as contributors to the global climate variability.Sedimentological and biostratigraphic analyses of sediment cores were coupled with shallow seismic images to investigate the origin and evolution of a pockmark field in the southwestern Barents Sea, an epicontinental sea part of the Arctic Ocean. The pockmarks formed as a result of reduced sedimentation above active gas seeps near the retreating edge of the Barents Sea ice sheet about 15,000 years ago. The seepage is ascribed to climate change-induced dissociation of methane hydrates. These findings strengthen the case that pockmarks, worldwide, recorded the release of massive quantities of methane from the seafloor into the ocean during the last deglaciation. No evidence was found for current upward methane flux, so the pockmarks in the study area appear as inactive seabed features. Field measurements of currents and sediment fluxes in pockmarks in the Oslofjord, Norway, along with an experimental hydrodynamics study, provide insight into the mechanisms responsible for the long-term maintenance of inactive pockmarks. Near-bed currents may control the net sedimentation rate in these depressions by inhibiting the sedimentation from suspended transport. Enhanced turbulence and more intense biological activity suggest that the suspended fines are supported in the water column more easily in the pockmarks than on the surrounding bed, and can be transported away before settling. Moreover, upwelling generated by flow deflection

  13. Do conservative and reactive tracers take the same water flow pathways? An experimental approach (United States)

    Kasteel, Roy; Koestel, Johannes; Vereecken, Harry


    Reactive transport modelling heavily relies on the assumption that the soil's hydraulic behavior, i.e. the solute transport volume (water content) and the water flow pathways (dispersivity), can be characterized by the use of a conservative tracer. However, there exits ample experimental evidence in the literature whether this assumption holds, mainly because of the lack of detection methods that are able to monitor solute transport with a high resolution in space and time. Time-lapse electrical resistivity tomography (ERT) supplies three-dimensional spatio-temporally resolved image data through minimally invasive measurements. ERT has proved to be a valuable tool for imaging solute transport processes in the subsurface and has the potential to resolve the above-mentioned issue. The goals of this study are to verify to what extent ERT can be used to compare flow pathways of a conservative tracer (chloride) and a reactive tracer (food-dye Brilliant Blue) in the same large soil monolith filled with an undisturbed loamy sand and eventually address the question whether they take the same flow pathways. A constant water flow field was established in the soil monolith by means of an irrigation device. The tracers chloride and Brilliant Blue were successively added to the irrigation water. The negative charge of both tracer provides an electrical conductivity contrast that can be detected by means of ERT. Time-lapse ERT provides a qualitative comparison between both tracers, by visualizing the three-dimensional transport behavior. A quantitative analysis was performed by parameterizing the voxel-scale breakthrough curves using the convection-dispersion equation, which includes retardation and sorption kinetics for the reactive tracer. At the voxel-scale, heterogeneous water flow was observed, identified by regions with different pore-water velocities. In the subsoil, these regions were aligned to soil structural features of the plough pan. We discuss the comparison of the

  14. Influence of the Fragmentation Process on the Eruptive Dynamics of Vulcanian Eruptions: an Experimental Approach (United States)

    Alatorre-Ibarguengoitia, M. A.; Arciniega-Ceballos, A.; Dingwell, D. B.; Richard, D.; Scheu, B.; Kueppers, U.; Delgado-Granados, H.; Navarrete Montesinos, M.


    During volcanic eruptions, the ejection velocity of the gas-pyroclast mixture is one of the main parameters that control the behavior of the eruptive column near the vent. Together with other factors such as density of the mixture, temperature and vent geometry, it determines whether a buoyant plume can develop or if the column will collapse leading to a pyroclastic flow. Thus, an accurate description of the relationship between conduit pressure and ejection velocity is required for an adequate hazard analysis. In addition, ejection velocities obtained from field observations allow us to estimate pre-eruption conduit pressures. Theoretical and experimental studies to date have largely neglected the effects of the magmatic fragmentation on the dynamics of the gas-pyroclast mixture. The eruptive dynamics of Vulcanian eruptions has been investigated using the 1-D shock-tube theory, which consists of pressurized magma separated from the air by a diaphragm. After the rupture of the diaphragm, a shock wave propagates into the air and a rarefaction wave propagates into the magma. If the differential pressure is high enough, a fragmentation front develops and travels through the magma while the fragments are ejected. For this study, fragmentation, ejection and shock wave velocities were simultaneously measured for each fragmentation experiment performed on natural volcanic samples with diverse porosities and different applied pressures (5-25 MPa). To this end, we used a synchronized array of dynamic pressure transducers, laser beams and receivers, charged wires and piezo film sensors. Our results show that the fragmentation process plays an important role in the dynamics of the gas-particles mixture for the following reasons: 1) the energy consumed by fragmentation reduces the energy available to accelerate the gas-particle mixture; 2) the grain-size distribution produced during fragmentation controls the mechanical and thermal coupling between the gas phase and the

  15. Manual strangulation: experimental approach to the genesis of hyoid bone fractures. (United States)

    Lebreton-Chakour, Catherine; Godio-Raboutet, Yves; Torrents, Romain; Chaumoitre, Kathia; Boval, Catherine; Bartoli, Christophe; Adalian, Pascal; Piercecchi-Marti, Marie-Dominique; Thollon, Lionel


    Discovery of a fracture of the hyoid bone during forensic autopsy is a feature that raises suspicions of constriction of the neck. Studies have shown the influence of gender and build of the individual on the morphology of this bone. Our aims were to confirm these findings and to develop an experimental protocol for simulating manual strangulation in order to determine the force required to fracture the hyoid bone and the influence of anthropometric parameters on this force. A total of 77 intact hyoid bones were obtained, scanned, modeled, measured and embedded in resin. Using a hydraulic press, we applied force to the distal extremity of the greater horn. The relationships between the parameters of sex, weight and height of the subject, anteroposterior length of the hyoid, width between the greater horns, angle, fusion of the greater horns and force applied were analyzed. Our study confirmed sexual dimorphism, shown by greater length in males (>37.8 mm) than in females, and a larger angle in females (a shorter bone with a width>43.7 mm and an angle>31°01). The study confirmed the positive correlation between the length of the hyoid and the weight and height of the subject (pbones fractured during the experiment (87% fracture rate). Of the fractures, 48% occurred at the junction between the body and the greater horns, 49% in the greater horns (mean distance from the distal extremity of the horn 17.33±4.37 mm), and 3% in the median part of the body. No significant association was found between gender and type of fracture, or between fusion or non-fusion of the horn (p>0.05). Fused bones were not more susceptible to fracture than non-fused bones. Fracture occurred at a mean force of 30.55 N (±18.189). Multiple linear regression showed a significant negative correlation between force required for fracture and age, weight and height of the subject, anteroposterior length and angle. The younger the individual, the slighter their build, the longer the bone and the

  16. Experimental-theoretical approach to carbon monoxide density calculation at the incipient stage of the fire indoors (United States)

    Puzach, S. V.; Suleykin, E. V.; Akperov, R. G.; Nguyen, T. D.


    A new experimental-theoretical approach to the toxic gases concentrations assessment in case of fire indoors is offered. The analytical formulas for calculation of CO average volume density are received. These formulas do not contain the geometrical sizes of the room and surfaces dimensions of combustible materials and, therefore, are valid under conditions of as a small-scale fire as a large-scale fire. A small-scale experimental installation for modeling fire thermal and gas dynamics in the closed or open thermodynamic system has been designed. The results of the experiments on determining dependencies of CO average volume density from average volume temperature and oxygen average volume density as well as dependencies of specific coefficients of CO emission and specific mass rates of the combustible material gasification from the time of tests during the burning of wood, transformer oil and PVC cables shield are presented. The results of numerical experiments on CO density calculation in small and large scale rooms using the proposed analytical solutions, integral, zone and field models for calculation of fire thermal and gas dynamics are presented. The comparison with the experimental data obtained by the authors and given in the literature has been performed. It is shown that CO density calculation in the full-scale room at the incipient stage of the fire can be carried out taking into account only the experimental dependences of CO from temperature or O2 density, that have been obtained from small-scale experiments. Therefore the solution of the equation of carbon monoxide mass conservation law is not necessary.

  17. Angiogenic activity of breast cancer patients' monocytes reverted by combined use of systems modeling and experimental approaches.

    Directory of Open Access Journals (Sweden)

    Nicolas Guex


    Full Text Available Angiogenesis plays a key role in tumor growth and cancer progression. TIE-2-expressing monocytes (TEM have been reported to critically account for tumor vascularization and growth in mouse tumor experimental models, but the molecular basis of their pro-angiogenic activity are largely unknown. Moreover, differences in the pro-angiogenic activity between blood circulating and tumor infiltrated TEM in human patients has not been established to date, hindering the identification of specific targets for therapeutic intervention. In this work, we investigated these differences and the phenotypic reversal of breast tumor pro-angiogenic TEM to a weak pro-angiogenic phenotype by combining Boolean modelling and experimental approaches. Firstly, we show that in breast cancer patients the pro-angiogenic activity of TEM increased drastically from blood to tumor, suggesting that the tumor microenvironment shapes the highly pro-angiogenic phenotype of TEM. Secondly, we predicted in silico all minimal perturbations transitioning the highly pro-angiogenic phenotype of tumor TEM to the weak pro-angiogenic phenotype of blood TEM and vice versa. In silico predicted perturbations were validated experimentally using patient TEM. In addition, gene expression profiling of TEM transitioned to a weak pro-angiogenic phenotype confirmed that TEM are plastic cells and can be reverted to immunological potent monocytes. Finally, the relapse-free survival analysis showed a statistically significant difference between patients with tumors with high and low expression values for genes encoding transitioning proteins detected in silico and validated on patient TEM. In conclusion, the inferred TEM regulatory network accurately captured experimental TEM behavior and highlighted crosstalk between specific angiogenic and inflammatory signaling pathways of outstanding importance to control their pro-angiogenic activity. Results showed the successful in vitro reversion of such an

  18. Assessment of the amorphous "solubility" of a group of diverse drugs using new experimental and theoretical approaches. (United States)

    Almeida e Sousa, Luis; Reutzel-Edens, Susan M; Stephenson, Gregory A; Taylor, Lynne S


    The supersaturation potential of poorly water-soluble compounds is of interest in the context of solubility enhancing formulations for enhanced bioavailability. In this regard, the amorphous "solubility", i.e., the maximum increase in solution concentration that can be obtained relative to the crystalline form, is an important parameter, albeit a very difficult one to evaluate experimentally. The goal of the current study was to develop new approaches to determine the amorphous "solubility" and to compare the experimental values to theoretical predictions. A group of six diverse model compounds was evaluated using the solvent exchange method to generate an amorphous phase in situ, determining the concentration at which the amorphous material was formed. The theoretical estimation of the amorphous "solubility" was based on the thermal properties of the crystalline and amorphous phases, the crystalline solubility, and the estimated concentration of water in the water-saturated amorphous phase. The formation of an amorphous precipitate could be captured transiently for all six compounds and hence the amorphous "solubility" determined experimentally. A comparison of the experimental amorphous "solubility" values to those calculated theoretically showed excellent agreement, in particular when the theoretical estimate method treated the precipitated phase as a supercooled liquid, and took into account heat capacity differences between the two forms. The maximum supersaturation ratio in water was found to be highly compound dependent, varying between 4 for ibuprofen and 54 for sorafenib. This information may be useful to predict improvements in biological exposure for poorly water-soluble compounds formulated as amorphous solid dispersions or other formulations that rely on supersaturation.

  19. Maximizing potential impact of experimental research into cognitive processes in health psychology: A systematic approach to material development. (United States)

    Hughes, Alicia M; Gordon, Rola; Chalder, Trudie; Hirsch, Colette R; Moss-Morris, Rona


    There is an abundance of research into cognitive processing biases in clinical psychology including the potential for applying cognitive bias modification techniques to assess the causal role of biases in maintaining anxiety and depression. Within the health psychology field, there is burgeoning interest in applying these experimental methods to assess potential cognitive biases in relation to physical health conditions and health-related behaviours. Experimental research in these areas could inform theoretical development by enabling measurement of implicit cognitive processes that may underlie unhelpful illness beliefs and help drive health-related behaviours. However, to date, there has been no systematic approach to adapting existing experimental paradigms for use within physical health research. Many studies fail to report how materials were developed for the population of interest or have used untested materials developed ad hoc. The lack of protocol for developing stimuli specificity has contributed to large heterogeneity in methodologies and findings. In this article, we emphasize the need for standardized methods for stimuli development and replication in experimental work, particularly as it extends beyond its original anxiety and depression scope to other physical conditions. We briefly describe the paradigms commonly used to assess cognitive biases in attention and interpretation and then describe the steps involved in comprehensive/robust stimuli development for attention and interpretation paradigms using illustrative examples from two conditions: chronic fatigue syndrome and breast cancer. This article highlights the value of preforming rigorous stimuli development and provides tools to aid researchers engage in this process. We believe this work is worthwhile to establish a body of high-quality and replicable experimental research within the health psychology literature. Statement of contribution What is already known on this subject? Cognitive

  20. An experimental design approach to the preparation of pegylated polylactide-co-glicolide gentamicin loaded microparticles for local antibiotic delivery

    Energy Technology Data Exchange (ETDEWEB)

    Dorati, Rossella; DeTrizio, Antonella; Genta, Ida; Grisoli, Pietro; Merelli, Alessia [Department of Drug Sciences, Viale Taramelli 12, University of Pavia, 27100, Pavia (Italy); Tomasi, Corrado [IENI CNR Lecco Unit, Via Promessi Sposi 29, 23900, Lecco (Italy); Conti, Bice, E-mail: [Department of Drug Sciences, Viale Taramelli 12, University of Pavia, 27100, Pavia (Italy)


    The present paper takes into account the DOE application to the preparation process of biodegradable microspheres for osteomyelitis local therapy. With this goal gentamicin loaded polylactide-co-glycolide-co-polyethyleneglycol (PLGA-PEG) microspheres were prepared and investigated. Two preparation protocols (o/w and w/o/w) with different process conditions, and three PLGA-PEG block copolymers with different compositions of lactic and glycolic acids and PEG, were tested. A Design Of Experiment (DOE) screening design was applied as an approach to scale up manufacturing step. The results of DOE screening design confirmed that w/o/w technique, the presence of salt and the 15%w/v polymer concentration positively affected the EE% (72.1–97.5%), and span values of particle size distribution (1.03–1.23), while salt addition alone negatively affected the yield process. Process scale up resulted in a decrease of gentamicin EE% that can be attributed to the high volume of water used to remove PVA and NaCl residues. The results of in vitro gentamicin release study show prolonged gentamicin release up to three months from the microspheres prepared with salt addition in the dispersing phase; the behavior being consistent with their highly compact structure highlighted by scanning electron microscopy analysis. The prolonged release of gentamicin is maintained even after embedding the biodegradable microspheres into a thermosetting composite gel made of chitosan and acellular bovine bone matrix (Orthoss® granules), and the microbiologic evaluation demonstrated the efficacy of the gentamicin loaded microspheres on Escherichia coli. The collected results confirm the feasibility of the scale up of microsphere manufacturing process and the high potential of the microparticulate drug delivery system to be used for the local antibiotic delivery to bone. - Highlights: • To get a more effective therapy for the prevention and treatment of osteomyelitis. • To exploit the local

  1. Modifying patch-scale connectivity to initiate landscape change: an experimental approach to link scales (United States)

    Peters, D. P.; Herrick, J.; Okin, G. S.; Pillsbury, F. C.; Duniway, M.; Vivoni, E. R.; Sala, O.; Havstad, K.; Monger, H. C.; Yao, J.; Anderson, J.


    Nonlinear interactions and feedbacks across spatial and temporal scales are common features of biological and physical systems. These emergent behaviors often result in surprises that challenge the ability of scientists to understand and predict system behavior at one scale based on information at finer or broader scales. Changes in ecosystem states under directional changes in climate represent a class of challenging dynamics of particular significance in many terrestrial ecosystems of the world. We are focusing on one system of global relevance and importance (conversion of arid grasslands to degraded shrublands). We are using a novel, multi-scale manipulative experiment to understand the key processes governing state changes, and to test specific hypotheses about how patterns and processes interact across scales to potentially reverse shrublands to grasslands or to other alternative states. We are using this experiment combined with simulation models to address two questions: (1) At what spatial scales do fine-scale processes propagate to exhibit broad-scale impacts? (2) At what spatial scales do broad-scale drivers overwhelm fine-scale processes? In this experiment, we initiate grass-soil feedbacks via the redistribution of resources at the plant and patch scale using Connectivity Modifiers (ConMods). These patterns are expected to propagate through time and space to influence grass dominance at the landscape scale with implications for regional scale land-atmosphere interactions. Initial results show that ConMods are effective in reducing horizontal water redistribution, and increasing local water availability to result in recruitment and growth of grasses and other herbaceous plants. We are integrating this information with a suite of process-based ecosystem-hydrologic-aeolian-atmospheric simulation models to investigate threshold dynamics and feedbacks across scales, and to predict alternative states under climate change. We believe this cross-scale approach

  2. An experimental approach to addressing ecological questions related to the conservation of plant biodiversity in China

    Directory of Open Access Journals (Sweden)

    Roy Turkington


    Full Text Available We briefly introduce and describe seven questions related to community structure and biodiversity conservation that can be addressed using field experiments, and provide the context for using the vast geographic diversity, biodiversity, and network of Nature Reserves in China to perform these experiments. China is the world's third largest country, has a diverse topography, covers five climatic zones from cold-temperate to tropical, has 18 vegetation biomes ranging from Arctic/alpine tundra and desert to Tropical rain forest, and supports the richest biodiversity in the temperate northern hemisphere (>10% of the world total. But this tremendous natural resource is under relentless assault that threatens to destroy biodiversity and negatively impact the services ecosystems provide. In an attempt to prevent the loss of biodiversity, China has established 2729 nature reserves which cover 14.84% of the nation's area. Unfortunately underfunding, mismanagement, illegal activities, invasive species and global climate change threaten the effectiveness of these protected areas. Attention has focused on protecting species and their habitats before degradation and loss of either species or habitats occur. Here we argue that we must move beyond the simple protection of ecosystems, beyond their description, and by using experiments, try to understand how ecosystems work. This new understanding will allow us to design conservation programs, perform restoration of damaged or degraded areas, and address resource management concerns (e.g., agriculture, logging, mining, hunting more effectively than with the current approach of ad hoc reactions to ecological and environmental problems. We argue that improving our understanding of nature can best be done using well designed, replicated, and typically manipulative field experiments.

  3. Late Neolithic Agriculture in Temperate Europe—A Long-Term Experimental Approach

    Directory of Open Access Journals (Sweden)

    Manfred Rösch


    Full Text Available Long-term slash-and-burn experiments, when compared with intensive tillage without manuring, resulted in a huge data set relating to potential crop yields, depending on soil quality, crop type, and agricultural measures. Cultivation without manuring or fallow phases did not produce satisfying yields, and mono-season cropping on freshly cleared and burned plots resulted in rather high yields, comparable to those produced during modern industrial agriculture - at least ten-fold the ones estimated for the medieval period. Continuous cultivation on the same plot, using imported wood from adjacent areas as fuel, causes decreasing yields over several years. The high yield of the first harvest of a slash-and-burn agriculture is caused by nutrient input through the ash produced and mobilization from the organic matter of the topsoil, due to high soil temperatures during the burning process and higher topsoil temperatures due to the soil’s black surface. The harvested crops are pure, without contamination of any weeds. Considering the amount of work required to fight weeds without burning, the slash-and-burn technique yields much better results than any other tested agricultural approach. Therefore, in dense woodland, without optimal soils and climate, slash-and-burn agriculture seems to be the best, if not the only, feasible method to start agriculture, for example, during the Late Neolithic, when agriculture expanded from the loess belt into landscapes less suitable for agriculture. Extensive and cultivation with manuring is more practical in an already-open landscape and with a denser population, but its efficiency in terms of the ratio of the manpower input to food output, is worse. Slash-and-burn agriculture is not only a phenomenon of temperate European agriculture during the Neolithic, but played a major role in land-use in forested regions worldwide, creating anthromes on a huge spatial scale.

  4. Integrated Experimental and Computational Approach to Understand the Effects of Heavy Ion Radiation on Skin Homeostasis.

    Energy Technology Data Exchange (ETDEWEB)

    von Neubeck, Claere; Shankaran, Harish; Geniza, Matthew; Kauer, Paula M.; Robinson, Robert J.; Chrisler, William B.; Sowa, Marianne B.


    The effects of low dose high linear energy transfer (LET) radiation on human health are of concern for both space and clinical exposures. As epidemiological data for such radiation exposures are scarce for making relevant predictions, we need to understand the mechanism of response especially in normal tissues. Our objective here is to understand the effects of heavy ion radiation on tissue homeostasis in a realistic model system. Towards this end, we exposed an in vitro three dimensional skin equivalent to low fluences of Neon (Ne) ions (300 MeV/u), and determined the differentiation profile as a function of time following exposure using immunohistochemistry. We found that Ne ion exposures resulted in transient increases in the tissue regions expressing the differentiation markers keratin 10, and filaggrin, and more subtle time-dependent effects on the number of basal cells in the epidermis. We analyzed the data using a mathematical model of the skin equivalent, to quantify the effect of radiation on cell proliferation and differentiation. The agent-based mathematical model for the epidermal layer treats the epidermis as a collection of heterogeneous cell types with different proliferation/differentiation properties. We obtained model parameters from the literature where available, and calibrated the unknown parameters to match the observed properties in unirradiated skin. We then used the model to rigorously examine alternate hypotheses regarding the effects of high LET radiation on the tissue. Our analysis indicates that Ne ion exposures induce rapid, but transient, changes in cell division, differentiation and proliferation. We have validated the modeling results by histology and quantitative reverse transcription polymerase chain reaction (qRT-PCR). The integrated approach presented here can be used as a general framework to understand the responses of multicellular systems, and can be adapted to other epithelial tissues.

  5. A combined experimental and theoretical approach to establish the relationship between shear force and clay platelet delamination in melt-processed polypropylene nanocomposites

    CSIR Research Space (South Africa)

    Bandyopadhyay, J


    Full Text Available In this article, a combined experimental and theoretical approach has been proposed to establish a relationship between the required shear force and the degree of delamination of clay tactoids during the melt-processing of polymer nanocomposites...

  6. Media effects, interpersonal communication and beyond: An experimental approach to study conversations about the media and their role in news reception

    National Research Council Canada - National Science Library

    Denise SOMMER


    .... An experimental approach to research on TV news effects is presented. It focuses on interpersonal communication about a newscast and simulates the social context of media use and media effects...

  7. The influence of biochar on substrate erodibility: An experimental approach with simulated rainfall (United States)

    Seitz, Steffen; Geißler, Christian; Goebes, Philipp; Teuber, Sandra; Scholten, Thomas


    Biochar is charcoal made from biomass by pyrolysis and used as a soil amendment. The addition of biochar to topsoils can lead to significant changes in soil characteristics. Nevertheless, the impact of biochar on soil functions is a controversial subject. It generally results from specific influences of substrates and biochar on the equilibrium between release (e.g. desorption) and fixation (e.g. adsorption) mechanisms. Furthermore, physical effects between soil and biochar are reported, which affect soil texture and thus mostly the transport and storage of water in substrates. It seems likely that while biochar influences biochemical and -physical processes, it can also affect soil erodibility. To investigate this assumption, an experimental rainfall simulation with splash cups was conducted. Different types ("HTC", "Pyrochar"; Delinat, Switzerland), sizes (biochar (2 %, 6 %, 10 %) were used in two substrates (sand and silt). Rainfall was induced with a single-nozzle rainfall simulator (Tübingen Rainfall Simulator) under a portable light frame tent (16 m3). The simulator was equipped with a Lechler 460.788.30 nozzle and adjusted to a drop falling height of 3.5 m (pressure at nozzle: 150 hPa). The sprinkle area was 1 m2 and rainfall was applied for 10 min with an intensity of 50 mm h-1 for all simulation runs (KE=5.13 J m-2 mm-1). The drop size spectrum and intensity of the simulator were calibrated and continuously checked using a "Laser Precipitation Monitor" (Thies GmbH) to ensure homogeneous rain characteristics. Results showed that the erodibility of both sand (p=0.006) and silt (p=0.094) decreased with biochar addition compared to treatments without biochar addition. The erodibility of sand was lower with HTC-char than with Pyrochar, but in silt it was lower with Pyrochar than with HTC-char. Nevertheless, the biochar type did not affect erodibility significantly. Sediment detachment was three-times higher in silt than in sand, both with and without biochar

  8. Evaluating uncertainty in 7Be-based soil erosion estimates: an experimental plot approach (United States)

    Blake, Will; Taylor, Alex; Abdelli, Wahid; Gaspar, Leticia; Barri, Bashar Al; Ryken, Nick; Mabit, Lionel


    Soil erosion remains a major concern for the international community and there is a growing need to improve the sustainability of agriculture to support future food security. High resolution soil erosion data are a fundamental requirement for underpinning soil conservation and management strategies but representative data on soil erosion rates are difficult to achieve by conventional means without interfering with farming practice and hence compromising the representativeness of results. Fallout radionuclide (FRN) tracer technology offers a solution since FRN tracers are delivered to the soil surface by natural processes and, where irreversible binding can be demonstrated, redistributed in association with soil particles. While much work has demonstrated the potential of short-lived 7Be (half-life 53 days), particularly in quantification of short-term inter-rill erosion, less attention has focussed on sources of uncertainty in derived erosion measurements and sampling strategies to minimise these. This poster outlines and discusses potential sources of uncertainty in 7Be-based soil erosion estimates and the experimental design considerations taken to quantify these in the context of a plot-scale validation experiment. Traditionally, gamma counting statistics have been the main element of uncertainty propagated and reported but recent work has shown that other factors may be more important such as: (i) spatial variability in the relaxation mass depth that describes the shape of the 7Be depth distribution for an uneroded point; (ii) spatial variability in fallout (linked to rainfall patterns and shadowing) over both reference site and plot; (iii) particle size sorting effects; (iv) preferential mobility of fallout over active runoff contributing areas. To explore these aspects in more detail, a plot of 4 x 35 m was ploughed and tilled to create a bare, sloped soil surface at the beginning of winter 2013/2014 in southwest UK. The lower edge of the plot was bounded by

  9. CFD approach to modelling, hydrodynamic analysis and motion characteristics of a laboratory underwater glider with experimental results

    Directory of Open Access Journals (Sweden)

    Yogang Singh


    Full Text Available Underwater gliders are buoyancy propelled vehicle which make use of buoyancy for vertical movement and wings to propel the glider in forward direction. Autonomous underwater gliders are a patented technology and are manufactured and marketed by corporations. In this study, we validate the experimental lift and drag characteristics of a glider from the literature using Computational fluid dynamics (CFD approach. This approach is then used for the assessment of the steady state characteristics of a laboratory glider designed at Indian Institute of Technology (IIT Madras. Flow behaviour and lift and drag force distribution at different angles of attack are studied for Reynolds numbers varying from 105 to 106 for NACA0012 wing configurations. The state variables of the glider are the velocity, gliding angle and angle of attack which are simulated by making use of the hydrodynamic drag and lift coefficients obtained from CFD. The effect of the variable buoyancy is examined in terms of the gliding angle, velocity and angle of attack. Laboratory model of glider is developed from the final design asserted by CFD. This model is used for determination of static and dynamic properties of an underwater glider which were validated against an equivalent CAD model and simulation results obtained from equations of motion of glider in vertical plane respectively. In the literature, only empirical approach has been adopted to estimate the hydrodynamic coefficients of the AUG that are required for its trajectory simulation. In this work, a CFD approach has been proposed to estimate the hydrodynamic coefficients and validated with experimental data. A two-mass variable buoyancy engine has been designed and implemented. The equations of motion for this two-mass engine have been obtained by modifying the single mass version of the equations described in the literature. The objectives of the present study are to understand the glider dynamics adopting a CFD approach

  10. Making and exploiting fullerenes, graphene, and carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Marcaccio, Massimo; Paolucci, Francesco (eds.) [Bologna Univ. (Italy). Dept. of Chemistry G. Ciamician


    This volume contains nine chapters which are presenting critical reviews of the present and future trends in modern chemistry research. The chapter ''Solubilization of Fullerenes, Carbon Nanotubes and Graphene'' by Alain Penicaud describes the various ingenious approaches to solve the solubility issue and describes in particular how graphite, and modern nanocarbons, can be made soluble by reductive dissolution. A large part of the present volume concerns the merging of nanocarbons with nanotechnology and their impact on technical development in many areas. Fullerenes, carbon nanotubes, nanodiamond and graphene find, for instance, various applications in the development of solar cells, including dye sensitized solar cells. The chapter ''Incorporation of Balls, Tubes and Bowls in Nanotechnology'' by James Mack describes the recent development of the area of fullerene fragments, and corannulene in particular, and their direct applications to organic light emitting diode (OLED) technology, while, in the chapter ''Exploiting Nanocarbons in Dye-Sensitized Solar Cells'' by Ladislav Kavan, the exploitation of nanocarbons in the development of novel dye sensitized solar cells with improved efficiency, durability and costs is thoroughly reviewed. The functionalization of CNSs has the invaluable advantage of combining their unique properties with those of other classes of materials. Supramolecular chemistry represents an elegant alternative approach for the construction of functional systems by means of noncovalent bonding interactions. In the chapter ''Supramolecular Chemistry of Carbon Nanotubes'' by Gildas Gavrel et al., the incredibly varied world of supramolecular, non-covalent functionalization of carbon nanotubes and their applications is examined and reviewed, and the synthetic strategies devised for fabricating mechanically-linked molecular architectures are described in the chapter &apos

  11. Life in the Clouds of Venus? An Experimental Synthetic Biology Approach (United States)

    Rothschild, L. J.; Paulino-Lima, I. G.; Amatya, D.; Bajar, B.; Geilich, B.; Hu, J.; Jackson, C. J.


    The surface of Venus constitutes the most hellish and biologically inhospitable planetary surface in our solar system, boasting a pH of 0, blistering winds that can melt lead, and pressures of 60 atm. However, during the earlier years of the solar system, without the runaway greenhouse effect that has plagued the planet, Venus potentially housed oceans and perhaps even life. There is a possibility that microbes could have retreated into hospitable niches in the atmosphere, as suggested by Carl Sagan as early as 1967 [1]. For example, 50 km above the raging hell of the Venusian surface, exists a relatively temperate environment that might serve as reservoir for life. This astrobiology project seeks to explore life at the extremes and to theorize whether microbial communities could not only survive but also reproduce in the Venusian atmosphere. Specifically, we ask: are aerosols viable microbial environments? But before we can test for life in the clouds, we have to develop a proper reporter to visualize cell growth in situ. For this purpose, we aimed to develop cell-growth dependent reporters to serve as remote biosensors for cell growth. We developed two using the polA promoter, a DNA-replication dependent promoter, and nrd operon promoter, a cell-cycle dependent promoter. Using these cell-growth reporters, the next step is to aerosolize microbes expressing these reporters in a suspension chamber adapted from a Millikan Drop Apparatus to assay reproduction in an aerosolized environment. Better yet is to test the reproduction of microbes in a microgravity regime such as on ISS.Approach: We engineered two cell-cycle dependent genetic reporters. One was the polA promoter which codes for DNA Polymerase I, a gene active in DNA replication [2]. The other was the nrdP. The activation of ribonucleotide reductase reduces ribonucleotides into deoxyribonucleotides and is involved in the bacterial cell cycle [3]. This promoter began activation during the initiation of DNA

  12. Tonic dopamine modulates exploitation of reward learning

    Directory of Open Access Journals (Sweden)

    Jeff A Beeler


    Full Text Available The impact of dopamine on adaptive behavior in a naturalistic environment is largely unexamined. Experimental work suggests that phasic dopamine is central to reinforcement learning whereas tonic dopamine may modulate performance without altering learning per se; however, this idea has not been developed formally or integrated with computational models of dopamine function. We quantitatively evaluate the role of tonic dopamine in these functions by studying the behavior of hyperdopaminergic DAT knockdown mice in an instrumental task in a semi-naturalistic homecage environment. In this closed economy paradigm, subjects earn all of their food by pressing either of two levers, but the relative cost for food on each lever shifts frequently. Compared to wild-type mice, hyperdopaminergic mice allocate more lever presses on high-cost levers, thus working harder to earn a given amount of food and maintain their body weight. However, both groups show a similarly quick reaction to shifts in lever cost, suggesting that the hyperdominergic mice are not slower at detecting changes, as with a learning deficit. We fit the lever choice data using reinforcement learning models to assess the distinction between acquisition and expression the models formalize. In these analyses, hyperdopaminergic mice displayed normal learning from recent reward history but diminished capacity to exploit this learning: a reduced coupling between choice and reward history. These data suggest that dopamine modulates the degree to which prior learning biases action selection and consequently alters the expression of learned, motivated behavior.

  13. Geosynergetic Approach for Analyze of Rock State, Theoretical and Experimental Redlts (United States)

    Hachay, O. A.; Khachay, A. Y.; Khachay, O. Y.


    releasing the system returns to the same phase trajectory attracting area. That is confirmed by detailed analyze of phase trajectories of seismic massive response before and after high energetic rock burst. In the book [5] is developed a new mathematical method for modeling of processes in local active continuum, which are energetically influenced from an outer energy source. The common cause of chaotization and stochastization of dynamical system movements are its losses of stability and exponential recession of near located phase trajectories together with its common boundedness and its common compression. The mathematical result coincides as a whole with the practical result: in the phase area the smaller attracting phase trajectories area exists where can occur an exponential recession of them, then the movement character changes and the further movement of phase points lead to return to the same attracting area. These movements can occur in resonance or spontaneous mood. The work was supported by the grant RFBR 10-05-00013. 1. Hachay, O.A., and Khachay, O.Yu. 2009. "Results of electromagnetic and seismic monitoring of the state of rock massive by use the approach of the open dynamical systems,"presented at the EGU2009 - EGU General Assembly 2009, session: Thermo- hydro- mechanical coupling in stressed rock, 19 April 19 - 24 April 2009. 2. Hachay, O.A. "Synergetic events in geological medium and nonlinear features of wave propagation," presented at the EGU2009 - EGU General Assembly 2009, session: Solid Earth geocomplexity: surface processes, morphology and natural resources over wide ranges of scale, 19 April 19 - 24 April 2009. 3. Chulichkov, A.I. 2003. Mathematical models of nonlinear dynamics. Moscow: Phismatlit, p.420. 4. Malineckiy, G.G. 2007. Mathematical base of synergetics. Moscow: LKI, p.375. 5. Naimark, Yu.I.and Landa, P.S. 2009. Stochastic and Chaotic oscillations. Moscow: Knigniy dom "LIBROKOM", p.424.

  14. An Effect Analysis of Comprehensive Treatment of Groundwater Over-Exploitation in Cheng'an County, Hebei Province, China. (United States)

    Shao, Weiwei; Zhou, Jinjun; Liu, Jiahong; Zhang, Haixing; Wang, Jianhua; Xiang, Chenyao; Yang, Guiyu; Tang, Yun


    The comprehensive treatment project of groundwater over-exploitation in Hebei Province has been implemented for more than a year, and the effect of exploitation restriction is in urgent need of evaluation. This paper deals with Cheng'an County of Hebei Province as the research subject. Based on collected hydro-meteorological, socioeconomic, groundwater, and other related data, together with typical regional experimental research, this study generates the effective precipitation-groundwater exploitation (P-W) curve and accompanying research methods, and calculates the quantity of groundwater exploitation restriction. It analyzes the target completion status of groundwater exploitation restriction through water conservancy measures and agricultural practices of the groundwater over-exploitation comprehensive treatment project that was implemented in Cheng'an County in 2014. The paper evaluates the treatment effect of groundwater over-exploitation, as well as provides technical support for the effect evaluation of groundwater exploitation restriction of agricultural irrigation in Cheng'an County and relevant areas.

  15. Experimental verification and analytical approach to influence stator skew on electromagnetic performance of permanent magnet generators with multipole rotor (United States)

    Choi, Jang-Young; Jang, Seok-Myeong; Ko, Kyoung-Jin


    This paper deals with experimental verification and analytical approach to influence stator skew on electromagnetic performance of a permanent magnet generator (PMG) with multipole rotor. The analytical expressions for magnetic field distributions are due to permanent magnets and the two-dimensional permeance function considering skew effects are established. On the basis of these analytical solutions, the analytical solutions for cogging torque and back-emf considering skew effects are also derived. Then, by applying estimated electrical parameters to a simple equivalent circuit of one phase for the PMG, output performances of the PMG with/without a skewed stator are investigated. Finally, by confirming that all analytical results are validated extensively by nonlinear finite element calculations and measurements, the validity of analysis methods presented in this paper is verified, and the influence stator skew on cogging torque, back-emf, and output performances of the PMG is also clearly described.

  16. Experimental metaphysics2 : The double standard in the quantum-information approach to the foundations of quantum theory (United States)

    Hagar, Amit

    Among the alternatives of non-relativistic quantum mechanics (NRQM) there are those that give different predictions than quantum mechanics in yet-untested circumstances, while remaining compatible with current empirical findings. In order to test these predictions, one must isolate one's system from environmental induced decoherence, which, on the standard view of NRQM, is the dynamical mechanism that is responsible for the 'apparent' collapse in open quantum systems. But while recent advances in condensed-matter physics may lead in the near future to experimental setups that will allow one to test the two hypotheses, namely genuine collapse vs. decoherence, hence make progress toward a solution to the quantum measurement problem, those philosophers and physicists who are advocating an information-theoretic approach to the foundations of quantum mechanics are still unwilling to acknowledge the empirical character of the issue at stake. Here I argue that in doing so they are displaying an unwarranted double standard.

  17. Experimental quantum digital signature over 102 km (United States)

    Yin, Hua-Lei; Fu, Yao; Liu, Hui; Tang, Qi-Jie; Wang, Jian; You, Li-Xing; Zhang, Wei-Jun; Chen, Si-Jing; Wang, Zhen; Zhang, Qiang; Chen, Teng-Yun; Chen, Zeng-Bing; Pan, Jian-Wei


    Quantum digital signature (QDS) is an approach to guarantee the nonrepudiation, unforgeability, and transferability of a signature with information-theoretical security. Previous experimental realizations of QDS relied on an unrealistic assumption of secure channels and the longest distance is several kilometers. Here, we have experimentally demonstrated a recently proposed QDS protocol without assuming any secure channel. Exploiting the decoy state modulation, we have successfully signed a one-bit message through an up to 102-km optical fiber. Furthermore, we continuously run the system to sign the longer message "USTC" with 32 bits at the distance of 51 km. Our results pave the way towards the practical application of QDS.

  18. An integrated approach to the design of tube hydroforming processes: artificial intelligence, numerical analysis and experimental investigation (United States)

    Di Lorenzo, R.; Filice, L.; Umbrello, D.; Micari, F.


    In the last years, the growing role of process flexibility in modern mechanical industries has driven a rising interest in optimisation of process/product design through innovative techniques. Moreover, the development of niche productions, which are characterised by low production volumes and small batches leads to the need of more flexible and rapid forming technologies. In this way, a great research effort is performed towards the study of new stamping processes: among them hydro forming finds a large interest in automotive industry since it allows to significantly reduce tooling costs and also to avoid some secondary operations. Different studies are available in the technical literature concerning the fundamentals of tube hydro forming processes as well as the industrial application of such operations. As process design issues are concerned, in the paper, the authors propose the integration of different tools, namely artificial intelligence techniques, numerical simulations and experimental knowledge to carry out tube hydro forming design. A fuzzy system was integrated with a FEM code for process simulation obtaining a sort of closed loop control system to be utilised in the process design phase. An experimental validation of the design procedure was developed as well proving the effectiveness of the proposed approach in order to obtain defect free components both as geometrical features and ductile fractures are concerned.

  19. The Effect of Screen Size on Mobile Phone User Comprehension of Health Information and Application Structure: An Experimental Approach. (United States)

    Al Ghamdi, Ebtisam; Yunus, Faisal; Da'ar, Omar; El-Metwally, Ashraf; Khalifa, Mohamed; Aldossari, Bakheet; Househ, Mowafa


    This research analyzes the impact of mobile phone screen size on user comprehension of health information and application structure. Applying experimental approach, we asked randomly selected users to read content and conduct tasks on a commonly used diabetes mobile application using three different mobile phone screen sizes. We timed and tracked a number of parameters, including correctness, effectiveness of completing tasks, content ease of reading, clarity of information organization, and comprehension. The impact of screen size on user comprehension/retention, clarity of information organization, and reading time were mixed. It is assumed on first glance that mobile screen size would affect all qualities of information reading and comprehension, including clarity of displayed information organization, reading time and user comprehension/retention of displayed information, but actually the screen size, in this experimental research, did not have significant impact on user comprehension/retention of the content or on understanding the application structure. However, it did have significant impact on clarity of information organization and reading time. Participants with larger screen size took shorter time reading the content with a significant difference in the ease of reading. While there was no significant difference in the comprehension of information or the application structures, there were a higher task completion rate and a lower number of errors with the bigger screen size. Screen size does not directly affect user comprehension of health information. However, it does affect clarity of information organization, reading time and user's ability to recall information.

  20. Experimental phase synchronization detection in non-phase coherent chaotic systems by using the discrete complex wavelet approach (United States)

    Ferreira, Maria Teodora; Follmann, Rosangela; Domingues, Margarete O.; Macau, Elbert E. N.; Kiss, István Z.


    Phase synchronization may emerge from mutually interacting non-linear oscillators, even under weak coupling, when phase differences are bounded, while amplitudes remain uncorrelated. However, the detection of this phenomenon can be a challenging problem to tackle. In this work, we apply the Discrete Complex Wavelet Approach (DCWA) for phase assignment, considering signals from coupled chaotic systems and experimental data. The DCWA is based on the Dual-Tree Complex Wavelet Transform (DT-CWT), which is a discrete transformation. Due to its multi-scale properties in the context of phase characterization, it is possible to obtain very good results from scalar time series, even with non-phase-coherent chaotic systems without state space reconstruction or pre-processing. The method correctly predicts the phase synchronization for a chemical experiment with three locally coupled, non-phase-coherent chaotic processes. The impact of different time-scales is demonstrated on the synchronization process that outlines the advantages of DCWA for analysis of experimental data.

  1. Identification of intrinsic defects in SiC: Towards an understanding of defect aggregates by combining theoretical and experimental approaches

    Energy Technology Data Exchange (ETDEWEB)

    Bockstedte, Michel; Mattausch, Alexander; Pankratov, Oleg [Lehrstuhl fuer Theoretische Festkoerperphysik, Universitaet Erlangen-Nuernberg, Erlangen (Germany); Gali, Adam [Department of Atomic Physics, Budapest University of Technology and Economics, Budapest (Hungary); Steeds, John W. [Department of Physics, University of Bristol (United Kingdom)


    In SiC, mobile point defects may form thermally stable clusters and aggregates, such as di-vacancies or carbon interstitial complexes. Although predicted by theory, experimental evidence of such clusters became available only recently. Combining theoretical and experimental approaches, the unique identification of the di-vacancy, the carbon vacancy-antisite complex with the spin resonance centers P6/P7 and SI5 was recently achieved. In this way also the di-carbon and tri-carbon antisites with the photoluminiscence centers P-T and U, HT3 and HT4, respectively were identified. The two identified vacancy complexes show distinct properties: while the di-vacancy, like the silicon vacancy possesses a high-spin ground state, the carbon vacancy-antisite complex, like the carbon vacancy, is a Jahn-Teller center. These effects consistently explain the complex properties of the spin resonance spectra and are discussed in detail for the isolated vacancies. The aggregation of vacancies proved to be relevant in the explantation of the kinetic deactivation of nitrogen in co-implanted SiC. This and further evidence for defect aggregates underline the relevance of this notion. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Post-release survival of surf scoters following an oil spill: an experimental approach to evaluating rehabilitation success (United States)

    De La Cruz, Susan E. W.; Takekawa, John Y.; Spragens, Kyle A.; Yee, Julie; Golightly, Richard T.; Massey, Greg; Henkel, Laird A.; Larsen, Scott; Ziccardi, Michael


    Birds are often the most numerous vertebrates damaged and rehabilitated in marine oil spills; however, the efficacy of avian rehabilitation is frequently debated and rarely examined experimentally. We compared survival of three radio-marked treatment groups, oiled, rehabilitated (ORHB), un-oiled, rehabilitated (RHB), and un-oiled, non-rehabilitated (CON), in an experimental approach to examine post-release survival of surf scoters (Melanitta perspicillata) following the 2007 M/V Cosco Busan spill in San Francisco Bay. Live encounter-dead recovery modeling indicated that survival differed among treatment groups and over time since release. The survival estimate (±SE) for ORHB was 0.143 ± 0.107 compared to CON (0.498 ± 0.168) and RHB groups (0.772 ± 0.229), suggesting scoters tolerated the rehabilitation process itself well, but oiling resulted in markedly lower survival. Future efforts to understand the physiological effects of oil type and severity on scoters are needed to improve post-release survival of this species.

  3. Post-release survival of surf scoters following an oil spill: an experimental approach to evaluating rehabilitation success. (United States)

    De la Cruz, Susan E W; Takekawa, John Y; Spragens, Kyle A; Yee, Julie; Golightly, Richard T; Massey, Greg; Henkel, Laird A; Scott Larsen, R; Ziccardi, Michael


    Birds are often the most numerous vertebrates damaged and rehabilitated in marine oil spills; however, the efficacy of avian rehabilitation is frequently debated and rarely examined experimentally. We compared survival of three radio-marked treatment groups, oiled, rehabilitated (ORHB), un-oiled, rehabilitated (RHB), and un-oiled, non-rehabilitated (CON), in an experimental approach to examine post-release survival of surf scoters (Melanitta perspicillata) following the 2007 M/V Cosco Busan spill in San Francisco Bay. Live encounter-dead recovery modeling indicated that survival differed among treatment groups and over time since release. The survival estimate (±SE) for ORHB was 0.143±0.107 compared to CON (0.498±0.168) and RHB groups (0.772±0.229), suggesting scoters tolerated the rehabilitation process itself well, but oiling resulted in markedly lower survival. Future efforts to understand the physiological effects of oil type and severity on scoters are needed to improve post-release survival of this species. Published by Elsevier Ltd.

  4. Mesostructural investigation of micron-sized glass particles during shear deformation – An experimental approach vs. DEM simulation

    Directory of Open Access Journals (Sweden)

    Torbahn Lutz


    Full Text Available The interdependency of structure and mechanical features of a cohesive powder packing is on current scientific focus and far from being well understood. Although the Discrete Element Method provides a well applicable and widely used tool to model powder behavior, non-trivial contact mechanics of micron-sized particles demand a sophisticated contact model. Here, a direct comparison between experiment and simulation on a particle level offers a proper approach for model validation. However, the simulation of a full scale shear-tester experiment with micron-sized particles, and hence, validating this simulation remains a challenge. We address this task by down scaling the experimental setup: A fully functional micro shear-tester was developed and implemented into an X-ray tomography device in order to visualize the sample on a bulk and particle level within small bulk volumes of the order of a few micro liter under well-defined consolidation. Using spherical micron-sized particles (30 μm, shear tests with a particle number accessible for simulations can be performed. Moreover, particle level analysis allows for a direct comparison of experimental and numerical results, e.g., regarding structural evolution. In this talk, we focus on density inhomogeneity and shear induced heterogeneity during compaction and shear deformation.

  5. Packaging of Sin Goods - Commitment or Exploitation?

    DEFF Research Database (Denmark)

    Nafziger, Julia

    to such self-control problems, and possibly exploit them, by offering different package sizes. In a competitive market, either one or three (small, medium and large) packages are offered. In contrast to common intuition, the large, and not the small package is a commitment device. The latter serves to exploit...

  6. The exploitation of Gestalt principles by magicians. (United States)

    Barnhart, Anthony S


    Magicians exploit a host of psychological principles in deceiving their audiences. Psychologists have recently attempted to pinpoint the most common psychological tendencies exploited by magicians. This paper highlights two co-occurring principles that appear to be the basis for many popular magic tricks: accidental alignment and good continuation.

  7. Key points in biotechnological patents to be exploited. (United States)

    García, Alfredo Mateos; López-Moya, José Rafael; Ramos, Patricia


    Patents in some biotechnological fields are controversial. Despite this fact, the number of patent applications increases every year. Total revenues in the global biotechnology market are expected to increase in the middle term. Nowadays, the bioeconomy is an important socio-economic area, which is reflected in the number of firms dedicated to or using biotechnology. The exploitation of biotechnological patents is an essential task in the management of intellectual capital. This paper explains the multiplicity of factors that influence the exploitation of biotechnological patents; specifically, the internal and external key points of patents exploitation. The external determining factors for patents are: (i) the market need for biotechnological products and services, (ii) the importance of the freedom to operate analysis before entering the market, and (iii) efficiency in prosecution by Patent Offices. This paper primarily focuses on the internal determining factors, more particularly, the characteristics that the patent's owner must take into consideration in order to have a strong, broad subject-matter in the granted patent. The experimentation needed to obtain an adequate scope of the subject- matter in the claims is a critical issue in the exploitation of a patent or patent application.

  8. Exploration, Exploitation, and Organizational Coordination Mechanisms

    Directory of Open Access Journals (Sweden)

    Silvio Popadiuk


    Full Text Available This paper presents an empirical relationship among exploration, exploitation, and organizational coordination mechanisms, classified as the centralization of decision-making, formalization, and connectedness. In order to analyze the findings of this survey, we used two techniques: Principal Component Analysis (PCA and Partial Least Squares Path Modeling (PLS-PM. Our analysis was supported by 249 answers from managers of companies located in Brazil (convenience sampling. Contrary to expectations, centralization and exploitation were negatively associated. Our data supports the research hypothesis that formalization is positively associated with exploitation. Although the relationship between formalization and exploration were significant, the result is contrary to the research hypothesis that we made. The relationships among connectedness and exploitation, and connectedness and exploration were both positive and significant. This relationship means that the more connectedness increases, the higher the likelihood of exploitation and exploration.

  9. OPERATION COBRA. Deliberate Attack, Exploitation (United States)


    Climate and weather - The summer of 1944 bad not been particularly hot, but it had been and was to be unusually and frustratingly wet. Approaching...spring of 1944 near Bordeaux . The division is reported to have contained Alsatians, Walloons and Roumanians and was believed to be up to full strength at...was extremely bad. They had been in France for 2 or 3 years, and were completely spoiled. France is a dangerous country, with its wine , women and its

  10. Identification of novel adhesins of M. tuberculosis H37Rv using integrated approach of multiple computational algorithms and experimental analysis.

    Directory of Open Access Journals (Sweden)

    Sanjiv Kumar

    Full Text Available Pathogenic bacteria interacting with eukaryotic host express adhesins on their surface. These adhesins aid in bacterial attachment to the host cell receptors during colonization. A few adhesins such as Heparin binding hemagglutinin adhesin (HBHA, Apa, Malate Synthase of M. tuberculosis have been identified using specific experimental interaction models based on the biological knowledge of the pathogen. In the present work, we carried out computational screening for adhesins of M. tuberculosis. We used an integrated computational approach using SPAAN for predicting adhesins, PSORTb, SubLoc and LocTree for extracellular localization, and BLAST for verifying non-similarity to human proteins. These steps are among the first of reverse vaccinology. Multiple claims and attacks from different algorithms were processed through argumentative approach. Additional filtration criteria included selection for proteins with low molecular weights and absence of literature reports. We examined binding potential of the selected proteins using an image based ELISA. The protein Rv2599 (membrane protein binds to human fibronectin, laminin and collagen. Rv3717 (N-acetylmuramoyl-L-alanine amidase and Rv0309 (L,D-transpeptidase bind to fibronectin and laminin. We report Rv2599 (membrane protein, Rv0309 and Rv3717 as novel adhesins of M. tuberculosis H37Rv. Our results expand the number of known adhesins of M. tuberculosis and suggest their regulated expression in different stages.

  11. High-temperature and melting behaviour of nanocrystalline refractory compounds: an experimental approach applied to thorium dioxide (United States)

    Cappia, F.; Hudry, D.; Courtois, E.; Janßen, A.; Luzzi, L.; Konings, R. J. M.; Manara, D.


    The behaviour from 1500 K up to melting of nanocrystalline (nc) thorium dioxide, the refractory binary oxide with the highest melting point (3651 K), was explored here for the first time using fast laser heating, multi-wavelength pyrometry and Raman spectroscopy for the analysis of samples quenched to room temperature. Nc-ThO2 was melted at temperatures hundreds of K below the melting temperature assessed for bulk thorium dioxide. A particular behaviour has been observed in the formed liquid and its co-existence with a partially restructured solid, possibly due to the metastable nature of the liquid itself. Raman spectroscopy was used to characterize the thermal-induced structural evolution of nc-ThO2. Assessment of a semi-empirical relation between the Raman active T2g mode peak characteristics (peak width and frequency) and crystallites size provided a powerful, fast and non-destructive tool to determine local crystallites growth within the nc-ThO2 samples before and after melting. This semi-quantitative analysis, partly based on a phonon-confinement model, constitutes an advantageous, more flexible, complementary approach to electron microscopy and powder x-ray diffraction (PXRD) for the crystallite size determination. The adopted experimental approach (laser heating coupled with Raman spectroscopy) is therefore proven to be a promising methodology for the high temperature investigation of nanostructured refractory oxides.

  12. Two-Photon Polarization Dependent Spectroscopy in Chirality: A Novel Experimental-Theoretical Approach to Study Optically Active Systems

    Directory of Open Access Journals (Sweden)

    Florencio E. Hernández


    Full Text Available Many phenomena, including life itself and its biochemical foundations are fundamentally rooted in chirality. Combinatorial methodologies for catalyst discovery and optimization remain an invaluable tool for gaining access to enantiomerically pure compounds in the development of pharmaceuticals, agrochemicals, and flavors. Some exotic metamaterials exhibiting negative refractive index at optical frequencies are based on chiral structures. Chiroptical activity is commonly quantified in terms of circular dichroism (CD and optical rotatory dispersion (ORD. However, the linear nature of these effects limits their application in the far and near-UV region in highly absorbing and scattering biological systems. In order to surmount this barrier, in recent years we made important advancements on a novel non linear, low-scatter, long-wavelength CD approach called two-photon absorption circular dichroism (TPACD. Herein we present a descriptive analysis of the optics principles behind the experimental measurement of TPACD, i.e., the double L-scan technique, and its significance using pulsed lasers. We also make an instructive examination and discuss the reliability of our theoretical-computational approach, which uses modern analytical response theory, within a Time-Dependent Density Functional Theory (TD-DFT approach. In order to illustrate the potential of this novel spectroscopic tool, we first present the experimental and theoretical results obtained in C2-symmetric, axially chiral R-(+-1,1'-bi(2-naphthol, R-BINOL, a molecule studied at the beginning of our investigation in this field. Next, we reveal some preliminary results obtained for (R-3,3′-diphenyl-2,2′-bi-1-naphthol, R-VANOL, and (R-2,2′-diphenyl-3,3′-(4-biphenanthrol, R-VAPOL. This family of optically active compounds has been proven to be a suitable model for the structure-property relationship study of TPACD, because its members are highly conjugated yet photo-stable, and easily

  13. Exploiting Genome Structure in Association Analysis (United States)

    Kim, Seyoung


    Abstract A genome-wide association study involves examining a large number of single-nucleotide polymorphisms (SNPs) to identify SNPs that are significantly associated with the given phenotype, while trying to reduce the false positive rate. Although haplotype-based association methods have been proposed to accommodate correlation information across nearby SNPs that are in linkage disequilibrium, none of these methods directly incorporated the structural information such as recombination events along chromosome. In this paper, we propose a new approach called stochastic block lasso for association mapping that exploits prior knowledge on linkage disequilibrium structure in the genome such as recombination rates and distances between adjacent SNPs in order to increase the power of detecting true associations while reducing false positives. Following a typical linear regression framework with the genotypes as inputs and the phenotype as output, our proposed method employs a sparsity-enforcing Laplacian prior for the regression coefficients, augmented by a first-order Markov process along the sequence of SNPs that incorporates the prior information on the linkage disequilibrium structure. The Markov-chain prior models the structural dependencies between a pair of adjacent SNPs, and allows us to look for association SNPs in a coupled manner, combining strength from multiple nearby SNPs. Our results on HapMap-simulated datasets and mouse datasets show that there is a significant advantage in incorporating the prior knowledge on linkage disequilibrium structure for marker identification under whole-genome association. PMID:21548809

  14. Preface of "The Second Symposium on Border Zones Between Experimental and Numerical Application Including Solution Approaches By Extensions of Standard Numerical Methods" (United States)

    Ortleb, Sigrun; Seidel, Christian


    In this second symposium at the limits of experimental and numerical methods, recent research is presented on practically relevant problems. Presentations discuss experimental investigation as well as numerical methods with a strong focus on application. In addition, problems are identified which require a hybrid experimental-numerical approach. Topics include fast explicit diffusion applied to a geothermal energy storage tank, noise in experimental measurements of electrical quantities, thermal fluid structure interaction, tensegrity structures, experimental and numerical methods for Chladni figures, optimized construction of hydroelectric power stations, experimental and numerical limits in the investigation of rain-wind induced vibrations as well as the application of exponential integrators in a domain-based IMEX setting.

  15. Global Climate Responses to Anthropogenic Groundwater Exploitation (United States)

    Zeng, Y.; Xie, Z.


    In this study, a groundwater exploitation scheme is incorporated into the earth system model, Community Earth System Model 1.2.0 (CESM1.2.0), which is called CESM1.2_GW, and the climatic responses to anthropogenic groundwater withdrawal are then investigated on global scale. The scheme models anthropogenic groundwater exploitation and consumption, which are then divided into agricultural irrigation, industrial use and domestic use. A group of 41-year ensemble groundwater exploitation simulations with six different initial conditions, and a group of ensemble control simulations without exploitation are conducted using the developed model CESM1.2_GW with water supplies and demands estimated. The results reveal that the groundwater exploitation and water consumption cause drying effects on soil moisture in deep layers and wetting effects in upper layers, along with a rapidly declining groundwater table in Central US, Haihe River Basin in China and Northern India and Pakistan where groundwater extraction are most severe in the world. The atmosphere also responds to anthropogenic groundwater exploitation. Cooling effects on lower troposphere appear in large areas of North China Plain and of Northern India and Pakistan. Increased precipitation occurs in Haihe River Basin due to increased evapotranspiration from irrigation. Decreased precipitation occurs in Northern India because water vapor here is taken away by monsoon anomalies induced by anthropogenic alteration of groundwater. The local reducing effects of anthropogenic groundwater exploitation on total terrestrial water storage evinces that water resource is unsustainable with the current high exploitation rate. Therefore, a balance between slow groundwater withdrawal and rapid human economic development must be achieved to maintain a sustainable water resource, especially in over-exploitation regions such as Central US, Northern China, India and Pakistan.

  16. Reasoning About Programs by Exploiting the Environment (United States)


    1i TITLE ( lude Security Ca .fcation) Reasoning about Programs by Exploiting the Environment rt 12. PERSONAL AUTHOR(S) w]ba1oa A Limor Fix axd...editions are obsolete. Reasoning About Programs by Exploiting the Environment * Limor Fix Fred B. Schneider TR 94-1409 February 1994 Department of Computer...agencies. Limor Fix is also supported, in part, by a Fullbright post-doctoral award. Reasoning about Programs by Exploiting the Environment ---- NITIS GRA&I

  17. Global change ecotoxicology: Identification of early life history bottlenecks in marine invertebrates, variable species responses and variable experimental approaches. (United States)

    Byrne, M


    Climate change is a threat to marine biota because increased atmospheric CO₂ is causing ocean warming, acidification, hypercapnia and decreased carbonate saturation. These stressors have toxic effects on invertebrate development. The persistence and success of populations requires all ontogenetic stages be completed successfully and, due to their sensitivity to environmental stressors, developmental stages may be a population bottleneck in a changing ocean. Global change ecotoxicology is being used to identify the marine invertebrate developmental stages vulnerable to climate change. This overview of research, and the methodologies used, shows that most studies focus on acidification, with few studies on ocean warming, despite a long history of research on developmental thermotolerance. The interactive effects of stressors are poorly studied. Experimental approaches differ among studies. Fertilization in many species exhibits a broad tolerance to warming and/or acidification, although different methodologies confound inter-study comparisons. Early development is susceptible to warming and most calcifying larvae are sensitive to acidification/increased pCO₂. In multistressor studies moderate warming diminishes the negative impact of acidification on calcification in some species. Development of non-calcifying larvae appears resilient to near-future ocean change. Although differences in species sensitivities to ocean change stressors undoubtedly reflect different tolerance levels, inconsistent handling of gametes, embryos and larvae probably influences different research outcomes. Due to the integrative 'developmental domino effect', life history responses will be influenced by the ontogenetic stage at which experimental incubations are initiated. Exposure to climate change stressors from early development (fertilization where possible) in multistressor experiments is needed to identify ontogenetic sensitivities and this will be facilitated by more consistent

  18. An Experimental Approach to Study Individual Differences in Infants' Intake and Satiation Behaviors during Bottle-Feeding. (United States)

    Ventura, Alison K; Mennella, Julie A


    As a group, bottle-fed infants are at higher risk for rapid weight gain compared with breast-fed infants. However, little is known about individual differences in feeding behaviors of bottle-feeding infants, as well as maternal and infant characteristics associated with bottle-feeding outcomes. We conducted a 2-day, within-subject study of 21 formula-feeding dyads; the within-subject factor was feeding condition: mother-led (ML; mothers were given the instruction to feed their infants as they typically would) vs. infant-led (IL; the experimenter ensured feeding began when infants signaled hunger and ended when they rejected the bottle on three consecutive occasions). Intake was determined by bottle weight; feedings were video-recorded and later analyzed to determine feeding duration and types of satiation behaviors displayed. Percent difference scores were calculated for each outcome as [((ML - IL)/IL) × 100] to standardize differences among dyads. Mothers completed questionnaires of feeding styles and infant temperament. On average, infants consumed ∼42% more formula during the ML- than IL-condition (p = 0.03). However, notable variation existed in difference scores for intake (range = -52.8% to 268.9%; higher scores reflect greater intake during ML than IL). Stepwise regression illustrated that greater intakes during the ML-condition were predicted by the combination of: (1) higher infant age; (2) lower levels of infant rhythmicity and adaptability; (3) higher levels of infant positive mood; and (4) lower levels of maternal restrictive and responsive feeding styles. This objective, experimental approach illustrated that variation in bottle-feeding outcomes is associated with characteristics of both members of the dyad.

  19. Exploiting Additive Manufacturing Infill in Topology Optimization for Improved Buckling Load

    Directory of Open Access Journals (Sweden)

    Anders Clausen


    Full Text Available Additive manufacturing (AM permits the fabrication of functionally optimized components with high geometrical complexity. The opportunity of using porous infill as an integrated part of the manufacturing process is an example of a unique AM feature. Automated design methods are still incapable of fully exploiting this design freedom. In this work, we show how the so-called coating approach to topology optimization provides a means for designing infill-based components that possess a strongly improved buckling load and, as a result, improved structural stability. The suggested approach thereby addresses an important inadequacy of the standard minimum compliance topology optimization approach, in which buckling is rarely accounted for; rather, a satisfactory buckling load is usually assured through a post-processing step that may lead to sub-optimal components. The present work compares the standard and coating approaches to topology optimization for the MBB beam benchmark case. The optimized structures are additively manufactured using a filamentary technique. This experimental study validates the numerical model used in the coating approach. Depending on the properties of the infill material, the buckling load may be more than four times higher than that of solid structures optimized under the same conditions.

  20. Risk assessment by dynamic representation of vulnerability, exploitation, and impact (United States)

    Cam, Hasan


    Assessing and quantifying cyber risk accurately in real-time is essential to providing security and mission assurance in any system and network. This paper presents a modeling and dynamic analysis approach to assessing cyber risk of a network in real-time by representing dynamically its vulnerabilities, exploitations, and impact using integrated Bayesian network and Markov models. Given the set of vulnerabilities detected by a vulnerability scanner in a network, this paper addresses how its risk can be assessed by estimating in real-time the exploit likelihood and impact of vulnerability exploitation on the network, based on real-time observations and measurements over the network. The dynamic representation of the network in terms of its vulnerabilities, sensor measurements, and observations is constructed dynamically using the integrated Bayesian network and Markov models. The transition rates of outgoing and incoming links of states in hidden Markov models are used in determining exploit likelihood and impact of attacks, whereas emission rates help quantify the attack states of vulnerabilities. Simulation results show the quantification and evolving risk scores over time for individual and aggregated vulnerabilities of a network.

  1. Postural Hand Synergies during Environmental Constraint Exploitation

    Directory of Open Access Journals (Sweden)

    Cosimo Della Santina


    Full Text Available Humans are able to intuitively exploit the shape of an object and environmental constraints to achieve stable grasps and perform dexterous manipulations. In doing that, a vast range of kinematic strategies can be observed. However, in this work we formulate the hypothesis that such ability can be described in terms of a synergistic behavior in the generation of hand postures, i.e., using a reduced set of commonly used kinematic patterns. This is in analogy with previous studies showing the presence of such behavior in different tasks, such as grasping. We investigated this hypothesis in experiments performed by six subjects, who were asked to grasp objects from a flat surface. We quantitatively characterized hand posture behavior from a kinematic perspective, i.e., the hand joint angles, in both pre-shaping and during the interaction with the environment. To determine the role of tactile feedback, we repeated the same experiments but with subjects wearing a rigid shell on the fingertips to reduce cutaneous afferent inputs. Results show the persistence of at least two postural synergies in all the considered experimental conditions and phases. Tactile impairment does not alter significantly the first two synergies, and contact with the environment generates a change only for higher order Principal Components. A good match also arises between the first synergy found in our analysis and the first synergy of grasping as quantified by previous work. The present study is motivated by the interest of learning from the human example, extracting lessons that can be applied in robot design and control. Thus, we conclude with a discussion on implications for robotics of our findings.

  2. Understanding the influence of biofilm accumulation on the hydraulic properties of soils: a mechanistic approach based on experimental data (United States)

    Carles Brangarí, Albert; Sanchez-Vila, Xavier; Freixa, Anna; Romaní, Anna M.; Fernàndez-Garcia, Daniel


    hydraulic properties of bio-amended variably saturated soils. The new mechanistic model provides analytical equations for the water retention curve and the relative permeability. The approach consists in assuming that the porous media behaves as an ensemble of capillary tubes, which may be obtained from the experimental saturation profile. This premise is extended by considering the existence of biofilm bodies composed of bacteria and EPS. These compounds display a channeled geometry that reshapes the pore space at the pore-scale following specific geometrical patterns and changes its volume with suction. The hydraulic properties of the bio-amended soil can then be derived from the integrate contribution of the two biofilm compounds separately. Model can successfully reproduce displacements of the soil-water retention curve towards higher saturations and permeability reductions of distinct orders of magnitude.

  3. Have health trends worsened in Greece as a result of the financial crisis? A quasi-experimental approach. (United States)

    Vandoros, Sotiris; Hessel, Philipp; Leone, Tiziana; Avendano, Mauricio


    Health in Greece deteriorated after the recent financial crisis, but whether this decline was caused by the recent financial crisis has not been established. This article uses a quasi-experimental approach to examine the impact of the recent financial crisis on health in Greece. Data came from the European Union Statistics on Income and Living Conditions survey for the years 2006-09. We applied a difference-in-differences approach that compares health trends before and after the financial crisis in Greece with trends in a control population (Poland) that did not experience a recession and had health trends comparable with Greece before the crisis. We used logistic regression to model the impact of the financial crisis on poor self-rated health, controlling for demographic confounders. Results provide strong evidence of a statistically significant negative effect of the financial crisis on health trends. Relative to the control population, Greece experienced a significantly larger increase in the odds of reporting poor health after the crisis (odds ratio, 1.16; 95% confidence interval, 1.04-1.29). There was no difference in health trends between Poland and Greece before the financial crisis, supporting a causal interpretation of health declines in Greece as a result of the financial crisis. Results provide evidence that trends in self-rated health in Greece worsened as a result of the recent financial crisis. Findings stress the need for urgent health policy responses to the recent economic collapse in Greece as the full impact of austerity measures unfolds in the coming years.

  4. Evaluation of Lithium-Ion Battery Equivalent Circuit Models for State of Charge Estimation by an Experimental Approach

    Directory of Open Access Journals (Sweden)

    Jinxin Fan


    Full Text Available To improve the use of lithium-ion batteries in electric vehicle (EV applications, evaluations and comparisons of different equivalent circuit models are presented in this paper. Based on an analysis of the traditional lithium-ion battery equivalent circuit models such as the Rint, RC, Thevenin and PNGV models, an improved Thevenin model, named dual polarization (DP model, is put forward by adding an extra RC to simulate the electrochemical polarization and concentration polarization separately. The model parameters are identified with a genetic algorithm, which is used to find the optimal time constant of the model, and the experimental data from a Hybrid Pulse Power Characterization (HPPC test on a LiMn2O4 battery module. Evaluations on the five models are carried out from the point of view of the dynamic performance and the state of charge (SoC estimation. The dynamic performances of the five models are obtained by conducting the Dynamic Stress Test (DST and the accuracy of SoC estimation with the Robust Extended Kalman Filter (REKF approach is determined by performing a Federal Urban Driving Schedules (FUDS experiment. By comparison, the DP model has the best dynamic performance and provides the most accurate SoC estimation. Finally, sensitivity of the different SoC initial values is investigated based on the accuracy of SoC estimation with the REKF approach based on the DP model. It is clear that the errors resulting from the SoC initial value are significantly reduced and the true SoC is convergent within an acceptable error.

  5. Model-Free Primitive-Based Iterative Learning Control Approach to Trajectory Tracking of MIMO Systems With Experimental Validation. (United States)

    Radac, Mircea-Bogdan; Precup, Radu-Emil; Petriu, Emil M


    This paper proposes a novel model-free trajectory tracking of multiple-input multiple-output (MIMO) systems by the combination of iterative learning control (ILC) and primitives. The optimal trajectory tracking solution is obtained in terms of previously learned solutions to simple tasks called primitives. The library of primitives that are stored in memory consists of pairs of reference input/controlled output signals. The reference input primitives are optimized in a model-free ILC framework without using knowledge of the controlled process. The guaranteed convergence of the learning scheme is built upon a model-free virtual reference feedback tuning design of the feedback decoupling controller. Each new complex trajectory to be tracked is decomposed into the output primitives regarded as basis functions. The optimal reference input for the control system to track the desired trajectory is next recomposed from the reference input primitives. This is advantageous because the optimal reference input is computed straightforward without the need to learn from repeated executions of the tracking task. In addition, the optimization problem specific to trajectory tracking of square MIMO systems is decomposed in a set of optimization problems assigned to each separate single-input single-output control channel that ensures a convenient model-free decoupling. The new model-free primitive-based ILC approach is capable of planning, reasoning, and learning. A case study dealing with the model-free control tuning for a nonlinear aerodynamic system is included to validate the new approach. The experimental results are given.

  6. Exploitative and Deceptive Resource Acquisition Strategies

    Directory of Open Access Journals (Sweden)

    Joshua J. Reynolds


    Full Text Available Life history strategy (LHS and life history contingencies (LHCs should theoretically influence the use of exploitative and deceptive resource acquisition strategies. However, little research has been done in this area. The purpose of the present work was to create measures of exploitative strategies and test the predictions of life history theory. Pilot studies developed and validated a behavioral measure of cheating called the Dot Game. The role of individual LHS and LHCs (manipulated via validated story primes on cheating was investigated in Study 1. Studies 2a through 2c were conducted to develop and validate a self-report measure called the Exploitative and Deceptive Resource Acquisition Strategy Scale (EDRASS. Finally, Study 3 investigated life history and EDRASS. Results indicated that while LHS influences exploitative strategies, life history contingences had little effect. Implications of these findings are discussed.

  7. Life History Theory and Exploitative Strategies

    Directory of Open Access Journals (Sweden)

    Joshua J. Reynolds


    Full Text Available Exploitative strategies involve depriving others of resources while enhancing one’s own. Life history theory suggests that there are individual differences (life history strategy and environmental characteristics (life history contingencies [LHCs] that influence the use of exploitative strategies. However, past work manipulating LHCs has found mixed evidence for the influence of this information on exploitative behavior. We present three studies that help clarify the effects of this type of information. Results indicated that younger individuals are most sensitive to LHC information. We also found, contrary to predictions, that communicating slow LHC information (i.e., high population density, intraspecific competition, and resource scarcity increased rather than decreased the temptation to engage in exploitative behavior. Limitations and future directions are discussed.

  8. Liposomal cancer therapy: exploiting tumor characteristics

    DEFF Research Database (Denmark)

    Kaasgaard, Thomas; Andresen, Thomas Lars


    the reader will gain: The review focuses on strategies that exploit characteristic features of solid tumors, such as abnormal vasculature, overexpression of receptors and enzymes, as well as acidic and thiolytic characteristics of the tumor microenvironment. Take home message: It is concluded that the design...... of new liposomal drug delivery systems that better exploit tumor characteristic features is likely to result in more efficacious cancer treatments....

  9. A theoretical and experimental approach toward the development of affinity adsorbents for GFP and GFP-fusion proteins purification. (United States)

    Fernandes, Cláudia S M; Pina, Ana Sofia; Dias, Ana M G C; Branco, Ricardo J F; Roque, Ana Cecília Afonso


    The green fluorescent protein (GFP) is widely employed to report on a variety of molecular phenomena, but its selective recovery is hampered by the lack of a low-cost and robust purification alternative. This work reports an integrated approach combining rational design and experimental validation toward the optimization of a small fully-synthetic ligand for GFP purification. A total of 56 affinity ligands based on a first-generation lead structure were rationally designed through molecular modeling protocols. The library of ligands was further synthesized by solid-phase combinatorial methods based on the Ugi reaction and screened against Escherichia coli extracts containing GFP. Ligands A4C2, A5C5 and A5C6 emerged as the new lead structures based on the high estimated theoretical affinity constants and the high GFP binding percentages and enrichment factors. The elution of GFP from these adsorbents was further characterized, where the best compromise between mild elution conditions, yield and purity was found for ligands A5C5 and A5C6. These were tested for purifying a model GFP-fusion protein, where ligand A5C5 yielded higher protein recovery and purity. The molecular interactions between the lead ligands and GFP were further assessed by molecular dynamics simulations, showing a wide range of potential hydrophobic and hydrogen-bond interactions. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Electrospinning: A versatile technique for making of 1D growth of nanostructured nanofibers and its applications: An experimental approach (United States)

    Patil, Jyoti V.; Mali, Sawanta S.; Kamble, Archana S.; Hong, Chang K.; Kim, Jin H.; Patil, Pramod S.


    One dimensional (1D) metal oxide nanostructures (1D-MONS) play a key role in the development of functional devices including energy conversion, energy storage and environmental devices. They are also used for some important biomedical products like wound dressings, filter media, drug delivery and tissue engineering. The electrospinning (ES) is the versatile technique for making of 1D growth of nanostructured nanofibers, an experimental approach and its applications. The present review is focused on the 1D growth of nanostructured nanofibers in different applications like dye sensitized solar cells, perovskite solar cells, fuel cells, lithium ion batteries, redox flow batteries, supercapacitor, photocatalytic, and gas sensors based on ZnO, TiO2, MnO2, WO3, V2O5, NiO, SnO2, Fe2O3 etc. metal oxides, their composites and carbon. This review article presents an introduction to various types of ES techniques and their technical details. Also, the advantages and disadvantages of each ES technique are summarized. The various technical details such as preparative parameters, post-deposition methods, applied electric field, solution feed rate and a distance between a tip to the collector are the key factors in order to obtain exotic 1D nanostructured materials. Also, the lucid literature survey on the growth of nanostructures of various metal oxides and application in different fields are covered in this review. Further, the future perspectives has also been discussed.

  11. Improved microbial conversion of de-oiled Jatropha waste into biohydrogen via inoculum pretreatment: process optimization by experimental design approach

    Directory of Open Access Journals (Sweden)

    Gopalakrishnan Kumar


    Full Text Available In this study various pretreatment methods of sewage sludge inoculum and the statistical process optimization of de-oiled jatropha waste have been reported. Peak hydrogen production rate (HPR and hydrogen yield (HY of 0.36 L H2/L-d and 20 mL H2/g Volatile Solid (VS were obtained when heat shock pretreatment (95 oC, 30 min was employed. Afterwards, an experimental design was applied to find the optimal conditions for H2 production using heat-pretreated seed culture. The optimal substrate concentration, pH and temperature were determined by using response surface methodology as 205 g/L, 6.53 and 55.1 oC, respectively. Under these circumstances, the highest HPR of 1.36 L H2/L-d was predicted. Verification tests proved the reliability of the statistical approach. As a result of the heat pretreatment and fermentation optimization, a significant (~ 4 folds increase in HPR was achieved. PCR-DGGE results revealed that Clostridium sp. were majorly present under the optimal conditions.

  12. Evaluating the effect of the Practical Approach to Care Kit on teaching medical students primary care: Quasi-experimental study. (United States)

    Mash, Robert; Pather, Michael; Rhode, Hilary; Fairall, Lara


    South Africa is committed to health reforms that strengthen primary health care. Preparing future doctors to work in primary care teams with other professionals is a priority, and medical schools have shifted towards community-based and decentralised training of medical students. To evaluate the effect on student performance of the Practical Approach to Care Kit (PACK) (an integrated decision-making tool for adult primary care) during the final phase of medical student training at Stellenbosch University. Clinical rotations in family medicine at clinics in the Western Cape. Mixed methods involving a quasi-experimental study and focus group interviews. Student examination performance was compared between groups with and without exposure to the PACK during their clinical training. Student groups exposed to PACK were interviewed at the end of their rotations. Student performance in examinations was significantly better in those exposed to the PACK. Students varied from using the PACK overtly or covertly during the consultation to checking up on decisions made after the consultation. Some felt that the PACK was more suitable for nurses or more junior students. Although tutors openly endorsed PACK, very few modelled the use of PACK in their clinical practice. The use of PACK in the final phase of undergraduate medical education improved their performance in primary care. Students might be more accepting and find the tool more useful in the earlier clinical rotations. Supervisors should be trained further in how to incorporate the use of the PACK in their practice and educational conversations.

  13. Mechanics of blast loading on the head models in the study of traumatic brain injury using experimental and computational approaches. (United States)

    Ganpule, S; Alai, A; Plougonven, E; Chandra, N


    Blast waves generated by improvised explosive devices can cause mild, moderate to severe traumatic brain injury in soldiers and civilians. To understand the interactions of blast waves on the head and brain and to identify the mechanisms of injury, compression-driven air shock tubes are extensively used in laboratory settings to simulate the field conditions. The overall goal of this effort is to understand the mechanics of blast wave-head interactions as the blast wave traverses the head/brain continuum. Toward this goal, surrogate head model is subjected to well-controlled blast wave profile in the shock tube environment, and the results are analyzed using combined experimental and numerical approaches. The validated numerical models are then used to investigate the spatiotemporal distribution of stresses and pressure in the human skull and brain. By detailing the results from a series of careful experiments and numerical simulations, this paper demonstrates that: (1) Geometry of the head governs the flow dynamics around the head which in turn determines the net mechanical load on the head. (2) Biomechanical loading of the brain is governed by direct wave transmission, structural deformations, and wave reflections from tissue-material interfaces. (3) Deformation and stress analysis of the skull and brain show that skull flexure and tissue cavitation are possible mechanisms of blast-induced traumatic brain injury.

  14. Generation of hydrate forms of paroxetine HCl from the amorphous state: an evaluation of thermodynamic and experimental predictive approaches. (United States)

    Pina, M Fátima; Pinto, João F; Sousa, João J; Craig, Duncan Q M; Zhao, Min


    In this study, we evaluate the use of theoretical thermodynamic analysis of amorphous paroxetine hydrochloride (HCl) as well as experimental assessment in order to identify the most promising approach to stability and dissolution behaviour prediction, particularly in relation to stoichiometric and nonstoichiometric hydrate formation. Differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared and X-ray diffraction techniques were used. Parameters including heat capacity, configurational thermodynamic quantities, fragility and relaxation time classified amorphous paroxetine HCl as a moderate fragile glass with a considerable degree of molecular mobility. Solubility studies indicated little advantage of the amorphous form over the crystalline due to conversion to the hydrate Form I during equilibration, while the dissolution rate was higher for the amorphous form under sink conditions. A marked difference in the physical stability of amorphous paroxetine HCl was observed between dry and low humidity storage, with the system recrystallizing to the hydrate form. We conclude that, in this particular case (amorphous conversion to the hydrate), water may be playing a dual role in both plasticizing the amorphous form and driving the equilibrium towards the hydrate form, hence prediction of recrystallization behaviour from amorphous characteristics may be confounded by the additional process of hydrate generation. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. A Closer Look at Social Psychologists' Silver Bullet: Inevitable and Evitable Side Effects of the Experimental Approach. (United States)

    Bless, Herbert; Burger, Axel M


    The main advantage of experimental research lies in the possibility of systematically investigating the causal relation between the variables of interest. The well-known advantages result from (a) the possibility to manipulate the independent variable, (b) random assignment of participants to the experimental conditions, and (c) the experimenter's control over the operationalization of the variables and the general experimental setting. We argue that it is exactly these elements that constitute core advantages of experimental research but that are-at the same time-associated with side effects, which are often out of focus when researchers derive theoretical conclusions from their experimental findings. We discuss potential restrictions linked to these core elements of experimental research. Implications for both theory development and research design are discussed. © The Author(s) 2016.

  16. Exploiting Wireless Received Signal Strength Indicators to Detect Evil-Twin Attacks in Smart Homes

    Directory of Open Access Journals (Sweden)

    Zhanyong Tang


    Full Text Available Evil-Twin is becoming a common attack in smart home environments where an attacker can set up a fake AP to compromise the security of the connected devices. To identify the fake APs, The current approaches of detecting Evil-Twin attacks all rely on information such as SSIDs, the MAC address of the genuine AP, or network traffic patterns. However, such information can be faked by the attacker, often leading to low detection rates and weak protection. This paper presents a novel Evil-Twin attack detection method based on the received signal strength indicator (RSSI. Our approach considers the RSSI as a fingerprint of APs and uses the fingerprint of the genuine AP to identify fake ones. We provide two schemes to detect a fake AP in two different scenarios where the genuine AP can be located at either a single or multiple locations in the property, by exploiting the multipath effect of the Wi-Fi signal. As a departure from prior work, our approach does not rely on any professional measurement devices. Experimental results show that our approach can successfully detect 90% of the fake APs, at the cost of a one-off, modest connection delay.

  17. Exploitation of the Virtual Worlds in Tourism and Tourism Education

    Directory of Open Access Journals (Sweden)

    Zejda Pavel


    Full Text Available Academics perceive a great potential of virtual worlds in various areas, including tourism and education. Efforts adapting the virtual worlds in practice are, however, still marginal. There is no clear definition of the virtual world. Therefore the author of this article attempts to provide one. The paper also focuses on the barriers of a wider exploitation of the virtual worlds and discusses the principles that might help to increase their potential in tourism area. One of the principles – gamification – favours a wider adaptation of the virtual worlds in tourism. Applying gamification principles provides visitors with some unique experiences while serving as a powerful marketing tool for institutions. The benefits of implementing tourism education activities based on cooperative principles set in an immersive environment of the virtual worlds are depicted afterwards. Finally, this paper includes successful case studies, which show advantages and drawbacks of some approaches in exploiting the virtual worlds in tourism and tourism education.

  18. Construct exploit constraint in crash analysis by bypassing canary (United States)

    Huang, Ning; Huang, Shuguang; Huang, Hui; Chang, Chao


    Selective symbolic execution is a common program testing technology. Developed on the basis of it, some crash analysis systems are often used to test the fragility of the program by constructing exploit constraints, such as CRAX. From the study of crash analysis based on symbolic execution, this paper find that this technology cannot bypass the canary stack protection mechanisms. This paper makes the improvement uses the API hook in Linux. Experimental results show that the use of API hook can effectively solve the problem that crash analysis cannot bypass the canary protection.

  19. Neuroproteomics and Systems Biology Approach to Identify Temporal Biomarker Changes Post Experimental Traumatic Brain Injury in Rats

    Directory of Open Access Journals (Sweden)

    Firas H Kobeissy


    Full Text Available Traumatic brain injury (TBI represents a critical health problem of which diagnosis, management and treatment remain challenging. TBI is a contributing factor in approximately 1/3 of all injury-related deaths in the United States. The Centers for Disease Control and Prevention (CDC estimate that 1.7 million TBI people suffer a TBI in the United States annually. Efforts continue to focus on elucidating the complex molecular mechanisms underlying TBI pathophysiology and defining sensitive and specific biomarkers that can aid in improving patient management and care. Recently, the area of neuroproteomics-systems biology is proving to be a prominent tool in biomarker discovery for central nervous system (CNS injury and other neurological diseases. In this work, we employed the controlled cortical impact (CCI model of experimental TBI in rat model to assess the temporal-global proteome changes after acute (1 day and for the first time, subacute (7 days, post-injury time frame using the established CAX-PAGE LC-MS/MS platform for protein separation combined with discrete systems biology analyses to identify temporal biomarker changes related to this rat TBI model. Rather than focusing on any one individual molecular entities, we used in silico systems biology approach to understand the global dynamics that govern proteins that are differentially altered post-injury. In addition, gene ontology analysis of the proteomic data was conducted in order to categorize the proteins by molecular function, biological process, and cellular localization. Results show alterations in several proteins related to inflammatory responses and oxidative stress in both acute (1 day and subacute (7 days periods post TBI. Moreover, results suggest a differential upregulation of neuroprotective proteins at 7-days post-CCI involved in cellular functions such as neurite growth, regeneration, and axonal guidance. Our study is amongst the first to assess temporal neuroproteome

  20. Potentially exploitable supercritical geothermal resources in the ductile crust (United States)

    Watanabe, Noriaki; Numakura, Tatsuya; Sakaguchi, Kiyotoshi; Saishu, Hanae; Okamoto, Atsushi; Ingebritsen, Steven E.; Tsuchiya, Noriyoshi


    The hypothesis that the brittle–ductile transition (BDT) drastically reduces permeability implies that potentially exploitable geothermal resources (permeability >10−16 m2) consisting of supercritical water could occur only in rocks with unusually high transition temperatures such as basalt. However, tensile fracturing is possible even in ductile rocks, and some permeability–depth relations proposed for the continental crust show no drastic permeability reduction at the BDT. Here we present experimental results suggesting that the BDT is not the first-order control on rock permeability, and that potentially exploitable resources may occur in rocks with much lower BDT temperatures, such as the granitic rocks that comprise the bulk of the continental crust. We find that permeability behaviour for fractured granite samples at 350–500 °C under effective confining stress is characterized by a transition from a weakly stress-dependent and reversible behaviour to a strongly stress-dependent and irreversible behaviour at a specific, temperature-dependent effective confining stress level. This transition is induced by onset of plastic normal deformation of the fracture surface (elastic–plastic transition) and, importantly, causes no ‘jump’ in the permeability. Empirical equations for this permeability behaviour suggest that potentially exploitable resources exceeding 450 °C may form at depths of 2–6 km even in the nominally ductile crust.

  1. Evaluating the effect of the Practical Approach to Care Kit on teaching medical students primary care: Quasi-experimental study

    Directory of Open Access Journals (Sweden)

    Robert Mash


    Full Text Available Background: South Africa is committed to health reforms that strengthen primary health care. Preparing future doctors to work in primary care teams with other professionals is a priority, and medical schools have shifted towards community-based and decentralised training of medical students.Aim: To evaluate the effect on student performance of the Practical Approach to Care Kit (PACK (an integrated decision-making tool for adult primary care during the final phase of medical student training at Stellenbosch University.Setting: Clinical rotations in family medicine at clinics in the Western Cape.Methods: Mixed methods involving a quasi-experimental study and focus group interviews. Student examination performance was compared between groups with and without exposure to the PACK during their clinical training. Student groups exposed to PACK were interviewed at the end of their rotations.Results: Student performance in examinations was significantly better in those exposed to the PACK. Students varied from using the PACK overtly or covertly during the consultation to checking up on decisions made after the consultation. Some felt that the PACK was more suitable for nurses or more junior students. Although tutors openly endorsed PACK, very few modelled the use of PACK in their clinical practice.Conclusion: The use of PACK in the final phase of undergraduate medical education improved their performance in primary care. Students might be more accepting and find the tool more useful in the earlier clinical rotations. Supervisors should be trained further in how to incorporate the use of the PACK in their practice and educational conversations.

  2. Experimental approaches to the interaction of the prion protein with nucleic acids and glycosaminoglycans: Modulators of the pathogenic conversion. (United States)

    Silva, Jerson L; Vieira, Tuane C R G; Gomes, Mariana P B; Rangel, Luciana P; Scapin, Sandra M N; Cordeiro, Yraima


    The concept that transmissible spongiform encephalopathies (TSEs) are caused only by proteins has changed the traditional paradigm that disease transmission is due solely to an agent that carries genetic information. The central hypothesis for prion diseases proposes that the conversion of a cellular prion protein (PrP(C)) into a misfolded, β-sheet-rich isoform (PrP(Sc)) accounts for the development of (TSE). There is substantial evidence that the infectious material consists chiefly of a protein, PrP(Sc), with no genomic coding material, unlike a virus particle, which has both. However, prions seem to have other partners that chaperone their activities in converting the PrP(C) into the disease-causing isoform. Nucleic acids (NAs) and glycosaminoglycans (GAGs) are the most probable accomplices of prion conversion. Here, we review the recent experimental approaches that have been employed to characterize the interaction of prion proteins with nucleic acids and glycosaminoglycans. A PrP recognizes many nucleic acids and GAGs with high affinities, and this seems to be related to a pathophysiological role for this interaction. A PrP binds nucleic acids and GAGs with structural selectivity, and some PrP:NA complexes can become proteinase K-resistant, undergoing amyloid oligomerization and conversion to a β-sheet-rich structure. These results are consistent with the hypothesis that endogenous polyanions (such as NAs and GAGs) may accelerate the rate of prion disease progression by acting as scaffolds or lattices that mediate the interaction between PrP(C) and PrP(Sc) molecules. In addition to a still-possible hypothesis that nucleic acids and GAGs, especially those from the host, may modulate the conversion, the recent structural characterization of the complexes has raised the possibility of developing new diagnostic and therapeutic strategies. Copyright © 2010 Elsevier Inc. All rights reserved.

  3. A comparative experimental approach to ecotoxicology in shallow-water and deep-sea holothurians suggests similar behavioural responses. (United States)

    Brown, Alastair; Wright, Roseanna; Mevenkamp, Lisa; Hauton, Chris


    Exploration of deep-sea mineral resources is burgeoning, raising concerns regarding ecotoxicological impacts on deep-sea fauna. Assessing toxicity in deep-sea species is technologically challenging, which promotes interest in establishing shallow-water ecotoxicological proxy species. However, the effects of temperature and hydrostatic pressure on toxicity, and how adaptation to deep-sea environmental conditions might moderate these effects, are unknown. To address these uncertainties we assessed behavioural and physiological (antioxidant enzyme activity) responses to exposure to copper-spiked artificial sediments in a laboratory experiment using a shallow-water holothurian (Holothuria forskali), and in an in situ experiment using a deep-sea holothurian (Amperima sp.). Both species demonstrated sustained avoidance behaviour, evading contact with contaminated artificial sediment. However, A. sp. demonstrated sustained avoidance of 5mgl -1 copper-contaminated artificial sediment whereas H. forskali demonstrated only temporary avoidance of 5mgl -1 copper-contaminated artificial sediment, suggesting that H. forskali may be more tolerant of metal exposure over 96h. Nonetheless, the acute behavioural response appears consistent between the shallow-water species and the deep-sea species, suggesting that H. forskali may be a suitable ecotoxicological proxy for A. sp. in acute (≤24h) exposures, which may be representative of deep-sea mining impacts. No antioxidant response was observed in either species, which was interpreted to be the consequence of avoiding copper exposure. Although these data suggest that shallow-water taxa may be suitable ecotoxicological proxies for deep-sea taxa, differences in methodological and analytical approaches, and in sex and reproductive stage of experimental subjects, require caution in assessing the suitability of H. forskali as an ecotoxicological proxy for A. sp. Nonetheless, avoidance behaviour may have bioenergetic consequences that

  4. A minimally invasive approach for open surgical thoracoabdominal aortic replacement: experimental concept for a novel surgical procedure. (United States)

    Andrási, Terézia B; Kékesi, Violetta; Merkely, Béla; Grossmann, Marius; Danner, Bernhard C; Schöndube, Friedrich A


    We aimed to develop a simple, reliable, and timesaving technique for the therapy of thoracoabdominal aortic (TAA) aneurysms that are not suitable for endovascular repair. In this pilot study, we sought to combine the advantages of classic open vascular procedure with the use of endoscopic surgical tools and small skin incisions to develop a minimally invasive approach for TAA replacement. The following procedures were used: endoscopic exposure and closure of the lower intercostal arteries; small posterolateral thoracotomy and left retroperitoneal incisions to expose the anastomotic regions of the aorta; partial anticoagulation; passive bypass and sequential aortic clamping; tunnelling of the graft through the native aortic lumen (endoaneurysmorrhaphy) and open performance of vascular anastomosis. Five mixed-breed dogs (25-35 kg) underwent minimally invasive TAA replacement. All animals survived the operation without blood transfusion (lowest Hb = 5.5 mg/dl). Total operation time was 364 ± 46.3 min. Clamping times were 17.6 ± 3.2 min for proximal anastomosis, 33.2 ± 2.48 min for visceral patch and 11 ± 2.3 min for distal anastomosis. The pull-through procedure of graft through the native aorta was performed during the visceral clamp time. Surgical replacement of the TAA through small transverse incisions of the thoracic and abdominal wall is feasible and allows open performance of all vascular anastomosis with no leakage at any anastomotic site. Further experimental studies and clinical implementation are needed to establish the safety and long-term outcome of minimally invasive TAA replacement as a possible primary therapeutic tool for complex aneurysms that are not suitable for endovascular treatment and require open surgical repair.

  5. Effect of glucose variability on pathways associated with glucotoxicity in diabetes: Evaluation of a novel in vitro experimental approach. (United States)

    Kuricová, Katarína; Pácal, Lukáš; Šoupal, Jan; Prázný, Martin; Kaňková, Kateřina


    Glycaemic variability (GV) has been hypothesized to increase the risk of diabetes complications; however, results of clinical studies are contradictory. The effect of GV on cell phenotypes has been investigated in vitro showing that GV may have more deleterious effect on cells that high glucose itself. However, methodology used to study GV in vitro differs significantly between studies and does not reflect in vivo situation. Therefore we aimed to establish clinically relevant an in vitro experimental approach for the study of GV that reflects intra-day glucose fluctuations of subjects with type 1 diabetes mellitus (T1DM) and of healthy subjects and to test how low and high GV affect expression of genes that protects cells from hyperglycaemia-induced damage. Human umbilical vein endothelial cells (HUVEC) were cultured 24h in medium with different glucose profiles: high GV, low GV and GV of healthy subjects-profiles created according to CGM of T1DM patients and healthy subjects. These profiles were compared to commonly used 5.5 and 25mmol/l glucose concentrations. Gene expression was determined using quantitative PCR. Our results showed general down-regulation of enzymes that are involved in the protection against hyperglycaemia-induced intracellular changes in both low and high GV compared to normal glycaemia similarly to the decrease induced by continuous hyperglycaemia. Gene expressions did not differ between high and low GV. Our data indicate that GV may have similar or even greater effect than continuous hyperglycaemia on the expression of several genes relevant to pathogenesis of diabetes microvascular complications. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. Exploitation in International Paid Surrogacy Arrangements. (United States)

    Wilkinson, Stephen


    Many critics have suggested that international paid surrogacy is exploitative. Taking such concerns as its starting point, this article asks: (1) how defensible is the claim that international paid surrogacy is exploitative and what could be done to make it less exploitative? (2) In the light of the answer to (1), how strong is the case for prohibiting it? Exploitation could in principle be dealt with by improving surrogates' pay and conditions. However, doing so may exacerbate problems with consent. Foremost amongst these is the argument that surrogates from economically disadvantaged countries cannot validly consent because their background circumstances are coercive. Several versions of this argument are examined and I conclude that at least one has some merit. The article's overall conclusion is that while ethically there is something to be concerned about, paid surrogacy is in no worse a position than many other exploitative commercial transactions which take place against a backdrop of global inequality and constrained options, such as poorly-paid and dangerous construction work. Hence, there is little reason to single surrogacy out for special condemnation. On a policy level, the case for prohibiting international commercial surrogacy is weak, despite legitimate concerns about consent and background poverty.

  7. Open questions in origin of life: experimental studies on the origin of nucleic acids and proteins with specific and functional sequences by a chemical synthetic biology approach

    DEFF Research Database (Denmark)

    Adamala, K.; Anella, F.; Wieczorek, R.


    In this mini-review we present some experimental approaches to the important issue in the origin of life, namely the origin of nucleic acids and proteins with specific and functional sequences. The formation of macromolecules on prebiotic Earth faces practical and conceptual difficulties. From...


    NARCIS (Netherlands)

    Ernst-Militaru, Rodica; Ghysels, Joris; Nijhof, Plonie

    To stimulate learning, both cognitive and metacognitive strategies are believed to be effective. This contribution reports on the experimental evaluation of an approach to develop metacognitive skills among students in secondary school. In the experiment 653 students of two schools and three age

  9. Use of vibrational spectroscopy to study protein and DNA structure, hydration, and binding of biomolecules: A combined theoretical and experimental approach

    DEFF Research Database (Denmark)

    Jalkanen, Karl J.; Jürgensen, Vibeke Würtz; Claussen, Anetta


    +disp, RHF, MP2, and DFT methodologies for the modeling studies with the goal of interpreting the experimentally measured vibrational spectra for these molecules to the greatest extent possible and to use this combined approach to understand the structure, function, and electronic properties...

  10. Open questions in origin of life : Experimental studies on the origin of nucleic acids and proteins with specific and functional sequences by a chemical synthetic biology approach

    NARCIS (Netherlands)

    Adamala, K.; Anella, F.M.; Wieczorek, R.; Stano, P.; Chiarabelli, C.; Luisi, P.L.


    In this mini-review we present some experimental approaches to the important issue in the origin of life, namely the origin of nucleic acids and proteins with specific and functional sequences. The formation of macromolecules on prebiotic Earth faces practical and conceptual difficulties. From the

  11. Rethinking exploitation: a process-centered account. (United States)

    Jansen, Lynn A; Wall, Steven


    Exploitation has become an important topic in recent discussions of biomedical and research ethics. This is due in no small measure to the influence of Alan Wertheimer's path-breaking work on the subject. This paper presents some objections to Wertheimer's account of the concept. The objections attempt to show that his account places too much emphasis on outcome-based considerations and too little on process-based considerations. Building on these objections, the paper develops an alternative process-centered account of the concept. This alternative account of exploitation takes as its point of departure the broadly Kantian notion that it is wrong to use another as an instrument for the advancement of one's own ends. It sharpens this slippery notion and adds a number of refinements to it. The paper concludes by arguing that process-centered accounts of exploitation better illuminate the ethical challenges posed by research on human subjects than outcome-centered accounts.

  12. Exploiting Weaknesses: An Approach to Counter Cartel Strategy (United States)


    company), FEMSA ( Coca - Cola ), Alfa (petrochemicals, food, telecommunications and auto parts), Axtel (telecommunications), Vitro (glass), Selther... China , and Global Terrorism.7 de Blij’s work provides the basic geospatial concepts that help describe the effects of the operational environment...Naval Postgraduate School, 2009). 7 Harm J. de Blij, Why Geography Matters; Three Challenges Facing America; Climate Change, the Rise if China

  13. Alcohol consumption and sudden unexpected death in epilepsy: experimental approach Consumo de álcool e morte súbita em epilepsia: uma abordagem experimental

    Directory of Open Access Journals (Sweden)

    Carla A. ScorzaI


    Full Text Available Using the pilocarpine model of epilepsy, we investigated the effects of alcohol consumption on the frequency of seizures in animals with epilepsy as well the underlying a possible association between alcohol intake and sudden unexpected death in epilepsy (SUDEP occurrence. Rats were divided randomly into two groups: (A rats with epilepsy and (B rats with epilepsy that received a daily dose of ethanol solution (350 mg kg-1, i.p. for 30 days. The basal frequency of seizures observed in the A and B groups during the first 30 days were 3.4±1.5 and 3.2±1.9 seizures per week per animal, respectively. In B group, it was observed a significant seizure increase (11.6±5.3 during the first 2 weeks of alcohol administration and quite interesting, one rat died suddenly after a generalized tonic-clonic seizure during this period. We concluded in our experimental study that exist a possible association between alcohol abuse and SUDEP occurrence.Utilizando o modelo de epilepsia induzido pela pilocarpina, investigamos os efeitos do consumo de álcool sobre a frequência de crises epilépticas em animais com epilepsia, como também uma possível associação entre a ingestão de álcool e ocorrência de morte súbita e inesperada nas epilepsias (SUDEP. Os animais foram randomicamente divididos em dois grupos: (A ratos com epilepsia e (B ratos com epilepsia que receberam uma dose diária de etanol (350 mg kg-1, i.p. por 30 dias consecutivos. A frequência basal de crises epilépticas observadas nos grupos A e B durante os primeiros 30 dias foram de 3,4±1,5 e 3,2±1,9 crises por semana/animal, respectivamente. No grupo B, ocorreu aumento significativo na frequência de crises (11,6±5,3 durante as duas primeiras semanas de administração do álcool e de forma interessante, um animal morreu subitamente após uma crise generalizada tônico-clonica durante esse período. Concluímos em nossa abordagem experimental que existe uma possível associação entre o

  14. Distinct Urban Mines: Exploiting secondary resources in unique anthropogenic spaces. (United States)

    Ongondo, F O; Williams, I D; Whitlock, G


    Fear of scarcity of resources highlight the need to exploit secondary materials from urban mines in the anthroposphere. Analogous to primary mines rich in one type of material (e.g. copper, gold, etc.), some urban mines are unique/distinct. We introduce, illustrate and discuss the concept of Distinct Urban Mines (DUM). Using the example of a university DUM in the UK, analogous to a primary mine, we illustrate potential product/material yields in respect of size, concentration and spatial location of the mine. Product ownership and replacement cycles for 17 high-value electrical and electronic equipment (EEE) among students showed that 20 tonnes of valuable e-waste were in stockpile in this DUM and a further 87 tonnes would 'soon' be available for exploitation. We address the opportunities and challenges of exploiting DUMs and conclude that they are readily available reservoirs for resource recovery. Two original contributions arise from this work: (i) a novel approach to urban mining with a potential for maximising resource recovery within the anthroposphere is conceptualised; and (ii) previously unavailable data for high-value products for a typical university DUM are presented and analysed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Evaluation of wind-induced internal pressure in low-rise buildings: A multi scale experimental and numerical approach (United States)

    Tecle, Amanuel Sebhatu

    Hurricane is one of the most destructive and costly natural hazard to the built environment and its impact on low-rise buildings, particularity, is beyond acceptable. The major objective of this research was to perform a parametric evaluation of internal pressure (IP) for wind-resistant design of low-rise buildings and wind-driven natural ventilation applications. For this purpose, a multi-scale experimental, i.e. full-scale at Wall of Wind (WoW) and small-scale at Boundary Layer Wind Tunnel (BLWT), and a Computational Fluid Dynamics (CFD) approach was adopted. This provided new capability to assess wind pressures realistically on internal volumes ranging from small spaces formed between roof tiles and its deck to attic to room partitions. Effects of sudden breaching, existing dominant openings on building envelopes as well as compartmentalization of building interior on the IP were systematically investigated. Results of this research indicated: (i) for sudden breaching of dominant openings, the transient overshooting response was lower than the subsequent steady state peak IP and internal volume correction for low-wind-speed testing facilities was necessary. For example a building without volume correction experienced a response four times faster and exhibited 30--40% lower mean and peak IP; (ii) for existing openings, vent openings uniformly distributed along the roof alleviated, whereas one sided openings aggravated the IP; (iii) larger dominant openings exhibited a higher IP on the building envelope, and an off-center opening on the wall exhibited (30--40%) higher IP than center located openings; (iv) compartmentalization amplif