WorldWideScience

Sample records for random search strategies

  1. Randomized Search Strategies With Imperfect Sensors

    National Research Council Canada - National Science Library

    Gage, Douglas W

    1993-01-01

    .... An important class of coverage applications are those that involve a search, in which a number of searching elements move about within a prescribed search area in order to find one or more target...

  2. Search for Directed Networks by Different Random Walk Strategies

    Science.gov (United States)

    Zhu, Zi-Qi; Jin, Xiao-Ling; Huang, Zhi-Long

    2012-03-01

    A comparative study is carried out on the efficiency of five different random walk strategies searching on directed networks constructed based on several typical complex networks. Due to the difference in search efficiency of the strategies rooted in network clustering, the clustering coefficient in a random walker's eye on directed networks is defined and computed to be half of the corresponding undirected networks. The search processes are performed on the directed networks based on Erdös—Rényi model, Watts—Strogatz model, Barabási—Albert model and clustered scale-free network model. It is found that self-avoiding random walk strategy is the best search strategy for such directed networks. Compared to unrestricted random walk strategy, path-iteration-avoiding random walks can also make the search process much more efficient. However, no-triangle-loop and no-quadrangle-loop random walks do not improve the search efficiency as expected, which is different from those on undirected networks since the clustering coefficient of directed networks are smaller than that of undirected networks.

  3. Random searching

    International Nuclear Information System (INIS)

    Shlesinger, Michael F

    2009-01-01

    There are a wide variety of searching problems from molecules seeking receptor sites to predators seeking prey. The optimal search strategy can depend on constraints on time, energy, supplies or other variables. We discuss a number of cases and especially remark on the usefulness of Levy walk search patterns when the targets of the search are scarce.

  4. Intermittent random walks: transport regimes and implications on search strategies

    International Nuclear Information System (INIS)

    Gomez Portillo, Ignacio; Campos, Daniel; Méndez, Vicenç

    2011-01-01

    We construct a transport model for particles that alternate rests of random duration and flights with random velocities. The model provides a balance equation for the mesoscopic particle density obtained from the continuous-time random walk framework. By assuming power laws for the distributions of waiting times and flight durations (for any velocity distribution with finite moments) we have found that the model can yield all the transport regimes ranging from subdiffusion to ballistic depending on the values of the characteristic exponents of the distributions. In addition, if the exponents satisfy a simple relationship it is shown how the competition between the tails of the distributions gives rise to a diffusive transport. Finally, we explore how the details of this intermittent transport process affect the success probability in an optimal search problem where an individual searcher looks for a target distributed (heterogeneously) in space. All the results are conveniently checked with numerical simulations

  5. Emergence of an optimal search strategy from a simple random walk.

    Science.gov (United States)

    Sakiyama, Tomoko; Gunji, Yukio-Pegio

    2013-09-06

    In reports addressing animal foraging strategies, it has been stated that Lévy-like algorithms represent an optimal search strategy in an unknown environment, because of their super-diffusion properties and power-law-distributed step lengths. Here, starting with a simple random walk algorithm, which offers the agent a randomly determined direction at each time step with a fixed move length, we investigated how flexible exploration is achieved if an agent alters its randomly determined next step forward and the rule that controls its random movement based on its own directional moving experiences. We showed that our algorithm led to an effective food-searching performance compared with a simple random walk algorithm and exhibited super-diffusion properties, despite the uniform step lengths. Moreover, our algorithm exhibited a power-law distribution independent of uniform step lengths.

  6. Evaluating random search strategies in three mammals from distinct feeding guilds.

    Science.gov (United States)

    Auger-Méthé, Marie; Derocher, Andrew E; DeMars, Craig A; Plank, Michael J; Codling, Edward A; Lewis, Mark A

    2016-09-01

    Searching allows animals to find food, mates, shelter and other resources essential for survival and reproduction and is thus among the most important activities performed by animals. Theory predicts that animals will use random search strategies in highly variable and unpredictable environments. Two prominent models have been suggested for animals searching in sparse and heterogeneous environments: (i) the Lévy walk and (ii) the composite correlated random walk (CCRW) and its associated area-restricted search behaviour. Until recently, it was difficult to differentiate between the movement patterns of these two strategies. Using a new method that assesses whether movement patterns are consistent with these two strategies and two other common random search strategies, we investigated the movement behaviour of three species inhabiting sparse northern environments: woodland caribou (Rangifer tarandus caribou), barren-ground grizzly bear (Ursus arctos) and polar bear (Ursus maritimus). These three species vary widely in their diets and thus allow us to contrast the movement patterns of animals from different feeding guilds. Our results showed that although more traditional methods would have found evidence for the Lévy walk for some individuals, a comparison of the Lévy walk to CCRWs showed stronger support for the latter. While a CCRW was the best model for most individuals, there was a range of support for its absolute fit. A CCRW was sufficient to explain the movement of nearly half of herbivorous caribou and a quarter of omnivorous grizzly bears, but was insufficient to explain the movement of all carnivorous polar bears. Strong evidence for CCRW movement patterns suggests that many individuals may use a multiphasic movement strategy rather than one-behaviour strategies such as the Lévy walk. The fact that the best model was insufficient to describe the movement paths of many individuals suggests that some animals living in sparse environments may use

  7. Optimization of refueling-shuffling scheme in PWR core by random search strategy

    International Nuclear Information System (INIS)

    Wu Yuan

    1991-11-01

    A random method for simulating optimization of refueling management in a pressurized water reactor (PWR) core is described. The main purpose of the optimization was to select the 'best' refueling arrangement scheme which would produce maximum economic benefits under certain imposed conditions. To fulfill this goal, an effective optimization strategy, two-stage random search method was developed. First, the search was made in a manner similar to the stratified sampling technique. A local optimum can be reached by comparison of the successive results. Then the other random experiences would be carried on between different strata to try to find the global optimum. In general, it can be used as a practical tool for conventional fuel management scheme. However, it can also be used in studies on optimization of Low-Leakage fuel management. Some calculations were done for a typical PWR core on a CYBER-180/830 computer. The results show that the method proposed can obtain satisfactory approach at reasonable low computational cost

  8. Search strategies

    Science.gov (United States)

    Oliver, B. M.

    Attention is given to the approaches which would provide the greatest chance of success in attempts related to the discovery of extraterrestrial advanced cultures in the Galaxy, taking into account the principle of least energy expenditure. The energetics of interstellar contact are explored, giving attention to the use of manned spacecraft, automatic probes, and beacons. The least expensive approach to a search for other civilizations involves a listening program which attempts to detect signals emitted by such civilizations. The optimum part of the spectrum for the considered search is found to be in the range from 1 to 2 GHz. Antenna and transmission formulas are discussed along with the employment of matched gates and filters, the probable characteristics of the signals to be detected, the filter-signal mismatch loss, surveys of the radio sky, the conduction of targeted searches.

  9. Optimal intermittent search strategies

    International Nuclear Information System (INIS)

    Rojo, F; Budde, C E; Wio, H S

    2009-01-01

    We study the search kinetics of a single fixed target by a set of searchers performing an intermittent random walk, jumping between different internal states. Exploiting concepts of multi-state and continuous-time random walks we have calculated the survival probability of a target up to time t, and have 'optimized' (minimized) it with regard to the transition probability among internal states. Our model shows that intermittent strategies always improve target detection, even for simple diffusion states of motion

  10. Optimal intermittent search strategies

    Energy Technology Data Exchange (ETDEWEB)

    Rojo, F; Budde, C E [FaMAF, Universidad Nacional de Cordoba, Ciudad Universitaria, X5000HUA Cordoba (Argentina); Wio, H S [Instituto de Fisica de Cantabria, Universidad de Cantabria and CSIC E-39005 Santander (Spain)

    2009-03-27

    We study the search kinetics of a single fixed target by a set of searchers performing an intermittent random walk, jumping between different internal states. Exploiting concepts of multi-state and continuous-time random walks we have calculated the survival probability of a target up to time t, and have 'optimized' (minimized) it with regard to the transition probability among internal states. Our model shows that intermittent strategies always improve target detection, even for simple diffusion states of motion.

  11. Intermittent random walks for an optimal search strategy: one-dimensional case

    International Nuclear Information System (INIS)

    Oshanin, G; Wio, H S; Lindenberg, K; Burlatsky, S F

    2007-01-01

    We study the search kinetics of an immobile target by a concentration of randomly moving searchers. The object of the study is to optimize the probability of detection within the constraints of our model. The target is hidden on a one-dimensional lattice in the sense that searchers have no a priori information about where it is, and may detect it only upon encounter. The searchers perform random walks in discrete time n = 0,1,2,...,N, where N is the maximal time the search process is allowed to run. With probability α the searchers step on a nearest-neighbour, and with probability (1-α) they leave the lattice and stay off until they land back on the lattice at a fixed distance L away from the departure point. The random walk is thus intermittent. We calculate the probability P N that the target remains undetected up to the maximal search time N, and seek to minimize this probability. We find that P N is a non-monotonic function of α, and show that there is an optimal choice α opt (N) of α well within the intermittent regime, 0 opt (N) N can be orders of magnitude smaller compared to the 'pure' random walk cases α = 0 and α = 1

  12. Cover times of random searches

    Science.gov (United States)

    Chupeau, Marie; Bénichou, Olivier; Voituriez, Raphaël

    2015-10-01

    How long must one undertake a random search to visit all sites of a given domain? This time, known as the cover time, is a key observable to quantify the efficiency of exhaustive searches, which require a complete exploration of an area and not only the discovery of a single target. Examples range from immune-system cells chasing pathogens to animals harvesting resources, from robotic exploration for cleaning or demining to the task of improving search algorithms. Despite its broad relevance, the cover time has remained elusive and so far explicit results have been scarce and mostly limited to regular random walks. Here we determine the full distribution of the cover time for a broad range of random search processes, including Lévy strategies, intermittent strategies, persistent random walks and random walks on complex networks, and reveal its universal features. We show that for all these examples the mean cover time can be minimized, and that the corresponding optimal strategies also minimize the mean search time for a single target, unambiguously pointing towards their robustness.

  13. Intermittent search strategies

    Science.gov (United States)

    Bénichou, O.; Loverdo, C.; Moreau, M.; Voituriez, R.

    2011-01-01

    This review examines intermittent target search strategies, which combine phases of slow motion, allowing the searcher to detect the target, and phases of fast motion during which targets cannot be detected. It is first shown that intermittent search strategies are actually widely observed at various scales. At the macroscopic scale, this is, for example, the case of animals looking for food; at the microscopic scale, intermittent transport patterns are involved in a reaction pathway of DNA-binding proteins as well as in intracellular transport. Second, generic stochastic models are introduced, which show that intermittent strategies are efficient strategies that enable the minimization of search time. This suggests that the intrinsic efficiency of intermittent search strategies could justify their frequent observation in nature. Last, beyond these modeling aspects, it is proposed that intermittent strategies could also be used in a broader context to design and accelerate search processes.

  14. Levy flights and random searches

    Energy Technology Data Exchange (ETDEWEB)

    Raposo, E P [Laboratorio de Fisica Teorica e Computacional, Departamento de Fisica, Universidade Federal de Pernambuco, Recife-PE, 50670-901 (Brazil); Buldyrev, S V [Department of Physics, Yeshiva University, New York, 10033 (United States); Da Luz, M G E [Departamento de Fisica, Universidade Federal do Parana, Curitiba-PR, 81531-990 (Brazil); Viswanathan, G M [Instituto de Fisica, Universidade Federal de Alagoas, Maceio-AL, 57072-970 (Brazil); Stanley, H E [Center for Polymer Studies and Department of Physics, Boston University, Boston, MA 02215 (United States)

    2009-10-30

    In this work we discuss some recent contributions to the random search problem. Our analysis includes superdiffusive Levy processes and correlated random walks in several regimes of target site density, mobility and revisitability. We present results in the context of mean-field-like and closed-form average calculations, as well as numerical simulations. We then consider random searches performed in regular lattices and lattices with defects, and we discuss a necessary criterion for distinguishing true superdiffusion from correlated random walk processes. We invoke energy considerations in relation to critical survival states on the edge of extinction, and we analyze the emergence of Levy behavior in deterministic search walks. Finally, we comment on the random search problem in the context of biological foraging.

  15. Efficient search by optimized intermittent random walks

    International Nuclear Information System (INIS)

    Oshanin, Gleb; Lindenberg, Katja; Wio, Horacio S; Burlatsky, Sergei

    2009-01-01

    We study the kinetics for the search of an immobile target by randomly moving searchers that detect it only upon encounter. The searchers perform intermittent random walks on a one-dimensional lattice. Each searcher can step on a nearest neighbor site with probability α or go off lattice with probability 1 - α to move in a random direction until it lands back on the lattice at a fixed distance L away from the departure point. Considering α and L as optimization parameters, we seek to enhance the chances of successful detection by minimizing the probability P N that the target remains undetected up to the maximal search time N. We show that even in this simple model, a number of very efficient search strategies can lead to a decrease of P N by orders of magnitude upon appropriate choices of α and L. We demonstrate that, in general, such optimal intermittent strategies are much more efficient than Brownian searches and are as efficient as search algorithms based on random walks with heavy-tailed Cauchy jump-length distributions. In addition, such intermittent strategies appear to be more advantageous than Levy-based ones in that they lead to more thorough exploration of visited regions in space and thus lend themselves to parallelization of the search processes.

  16. Switching strategies to optimize search

    International Nuclear Information System (INIS)

    Shlesinger, Michael F

    2016-01-01

    Search strategies are explored when the search time is fixed, success is probabilistic and the estimate for success can diminish with time if there is not a successful result. Under the time constraint the problem is to find the optimal time to switch a search strategy or search location. Several variables are taken into account, including cost, gain, rate of success if a target is present and the probability that a target is present. (paper: interdisciplinary statistical mechanics)

  17. Search along persistent random walks

    International Nuclear Information System (INIS)

    Friedrich, Benjamin M

    2008-01-01

    Optimal search strategies and their implementations in biological systems are a subject of active research. Here we study a search problem which is motivated by the hunt of sperm cells for the egg. We ask for the probability for an active swimmer to find a target under the condition that the swimmer starts at a certain distance from the target. We find that success probability is maximal for a certain level of fluctuations characterized by the persistence length of the swimming path of the swimmer. We derive a scaling law for the optimal persistence length as a function of the initial target distance and search time by mapping the search on a polymer physics problem

  18. Tales from the Field: Search Strategies Applied in Web Searching

    Directory of Open Access Journals (Sweden)

    Soohyung Joo

    2010-08-01

    Full Text Available In their web search processes users apply multiple types of search strategies, which consist of different search tactics. This paper identifies eight types of information search strategies with associated cases based on sequences of search tactics during the information search process. Thirty-one participants representing the general public were recruited for this study. Search logs and verbal protocols offered rich data for the identification of different types of search strategies. Based on the findings, the authors further discuss how to enhance web-based information retrieval (IR systems to support each type of search strategy.

  19. University Students' Online Information Searching Strategies in Different Search Contexts

    Science.gov (United States)

    Tsai, Meng-Jung; Liang, Jyh-Chong; Hou, Huei-Tse; Tsai, Chin-Chung

    2012-01-01

    This study investigates the role of search context played in university students' online information searching strategies. A total of 304 university students in Taiwan were surveyed with questionnaires in which two search contexts were defined as searching for learning, and searching for daily life information. Students' online search strategies…

  20. A stochastic model for intermittent search strategies

    International Nuclear Information System (INIS)

    Benichou, O; Coppey, M; Moreau, M; Suet, P H; Voituriez, R

    2005-01-01

    It is often necessary, in scientific or everyday life problems, to find a randomly hidden target. What is then the optimal strategy to reach it as rapidly as possible? In this article, we develop a stochastic theory for intermittent search behaviours, which are often observed: the searcher alternates phases of intensive search and slow motion with fast displacements. The first results of this theory have already been announced recently. Here we provide a detailed presentation of the theory, as well as the full derivation of the results. Furthermore, we explicitly discuss the minimization of the time needed to find the target

  1. PREFACE: The random search problem: trends and perspectives The random search problem: trends and perspectives

    Science.gov (United States)

    da Luz, Marcos G. E.; Grosberg, Alexander; Raposo, Ernesto P.; Viswanathan, Gandhi M.

    2009-10-01

    very important to solve computationally complex problems (e.g., protein folding), which involve optimizations in very high dimensional energy landscapes. On the other hand, random searches can also be studied from the perspective of diffusion and transport properties which is an important topic in condensed matter and statistical physics. For instance, the features of light scattered in a media, where the scatterers have a power-law distribution of sizes in many aspects, may resemble the patterns generated by a searcher performing Lévy walks. There are many questions related to random searches: how the searcher moves or should move, what are the patterns generated during the locomotion, how do the encounter rates depend on parameters of the search, etc. But perhaps, the most well known issue is how to optimize the search for specific target scenarios. The optimization can be in either continuous or discrete environments, when the information available is limited. The answer to this question determines specific strategies of movement that would maximize some properly defined search efficiency measure. The relevance of the question stems from the fact that the strategy-dynamics represents one of the most important factors that modulate the rate of encounters (e.g., the encounter rate between predator and prey). In the general context, strategy choices can be essential in determining the outcome and thus the success of a given search. For instance, realistic searches—and locomotion in general—require the expenditure of energy. Thus, inefficient search could deplete energy reserves (e.g., fat) and lead to rates of encounters below a minimum acceptable threshold (resulting in extinction of a species, for example). The framework of the random search `game' distinguishes between the two interacting players in a context of pursuit and chance. They are either a `searcher' (e.g., predator, protein, radar, `crawler') or a `target' (e.g., prey, DNA sequence, a missing

  2. Constructing Effective Search Strategies for Electronic Searching.

    Science.gov (United States)

    Flanagan, Lynn; Parente, Sharon Campbell

    Electronic databases have grown tremendously in both number and popularity since their development during the 1960s. Access to electronic databases in academic libraries was originally offered primarily through mediated search services by trained librarians; however, the advent of CD-ROM and end-user interfaces for online databases has shifted the…

  3. The Effect of Teaching Search Strategies on Perceptual Performance.

    Science.gov (United States)

    van der Gijp, Anouk; Vincken, Koen L; Boscardin, Christy; Webb, Emily M; Ten Cate, Olle Th J; Naeger, David M

    2017-06-01

    Radiology expertise is dependent on the use of efficient search strategies. The aim of this study is to investigate the effect of teaching search strategies on trainee's accuracy in detecting lung nodules at computed tomography. Two search strategies, "scanning" and "drilling," were tested with a randomized crossover design. Nineteen junior radiology residents were randomized into two groups. Both groups first completed a baseline lung nodule detection test allowing a free search strategy, followed by a test after scanning instruction and drilling instruction or vice versa. True positive (TP) and false positive (FP) scores and scroll behavior were registered. A mixed-design analysis of variance was applied to compare the three search conditions. Search strategy instruction had a significant effect on scroll behavior, F(1.3) = 54.2, P search (M = 15.3, SD = 4.6), t(18) = 4.44, P search. FP scores for drilling (M = 7.3, SD = 5.6) were significantly lower than for free search (M = 12.5, SD = 7.8), t(18) = 4.86, P < 0.001. Teaching a drilling strategy is preferable to teaching a scanning strategy for finding lung nodules. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  4. Searching CLEF-IP by Strategy

    NARCIS (Netherlands)

    W. Alink (Wouter); R. Cornacchia (Roberto); A.P. de Vries (Arjen)

    2010-01-01

    htmlabstractTasks performed by intellectual property specialists are often ad hoc, and continuously require new approaches to search a collection of documents. We therefore investigate the benets of a visual `search strategy builder' to allow IP search experts to express their approach to

  5. Quantum random-walk search algorithm

    International Nuclear Information System (INIS)

    Shenvi, Neil; Whaley, K. Birgitta; Kempe, Julia

    2003-01-01

    Quantum random walks on graphs have been shown to display many interesting properties, including exponentially fast hitting times when compared with their classical counterparts. However, it is still unclear how to use these novel properties to gain an algorithmic speedup over classical algorithms. In this paper, we present a quantum search algorithm based on the quantum random-walk architecture that provides such a speedup. It will be shown that this algorithm performs an oracle search on a database of N items with O(√(N)) calls to the oracle, yielding a speedup similar to other quantum search algorithms. It appears that the quantum random-walk formulation has considerable flexibility, presenting interesting opportunities for development of other, possibly novel quantum algorithms

  6. Routine development of objectively derived search strategies

    Directory of Open Access Journals (Sweden)

    Hausner Elke

    2012-02-01

    Full Text Available Abstract Background Over the past few years, information retrieval has become more and more professionalized, and information specialists are considered full members of a research team conducting systematic reviews. Research groups preparing systematic reviews and clinical practice guidelines have been the driving force in the development of search strategies, but open questions remain regarding the transparency of the development process and the available resources. An empirically guided approach to the development of a search strategy provides a way to increase transparency and efficiency. Methods Our aim in this paper is to describe the empirically guided development process for search strategies as applied by the German Institute for Quality and Efficiency in Health Care (Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen, or "IQWiG". This strategy consists of the following steps: generation of a test set, as well as the development, validation and standardized documentation of the search strategy. Results We illustrate our approach by means of an example, that is, a search for literature on brachytherapy in patients with prostate cancer. For this purpose, a test set was generated, including a total of 38 references from 3 systematic reviews. The development set for the generation of the strategy included 25 references. After application of textual analytic procedures, a strategy was developed that included all references in the development set. To test the search strategy on an independent set of references, the remaining 13 references in the test set (the validation set were used. The validation set was also completely identified. Discussion Our conclusion is that an objectively derived approach similar to that used in search filter development is a feasible way to develop and validate reliable search strategies. Besides creating high-quality strategies, the widespread application of this approach will result in a

  7. Random search for a dark resonance

    DEFF Research Database (Denmark)

    Kiilerich, Alexander Holm; Mølmer, Klaus

    A pair of resonant laser fields can drive a three-level system into a dark state where it ceases to absorb and emit radiation due to destructive interference. We propose a scheme to search for this resonance by randomly changing the frequency of one of the fields each time a fluorescence photon...

  8. Collaborative Search Strategies for Green Innovation

    DEFF Research Database (Denmark)

    Ørding Olsen, Anders; Sofka, Wolfgang; Grimpe, Christoph

    Recent innovation and strategy research emphasizes the importance of firm’s search for external knowledge to improve innovation performance. We focus on such search strategies within the domain of sustainable innovation in which problems are inherently complex and the relevant knowledge is widely...... dispersed. Hence, firms need to collaborate. We shed new light on collaborative search strategies led by firms in general and for solving environmental problems in particular. Both topics are largely absent in the extant open innovation literature. Using data from the European Seventh Framework Program...... for Research and Technological Development (FP7), our results indicate that the problem-solving potential of a search strategy increases with the diversity of existing knowledge of the partners in a consortium and with the experience of the partners involved. Moreover, we identify a substantial negative effect...

  9. Formalized search strategies for human risk contributions

    International Nuclear Information System (INIS)

    Rasmussen, J.; Pedersen, O.M.

    1982-07-01

    For risk management, the results of a probabilistic risk analysis (PRA) as well as the underlying assumptions can be used as references in a closed-loop risk control; and the analyses of operational experiences as a means of feedback. In this context, the need for explicit definition and documentation of the PRA coverage, including the search strategies applied, is discussed and aids are proposed such as plant description in terms of a formal abstraction hierarchy and use of cause-consequence-charts for the documentation of not only the results of PRA but also of its coverage. Typical human risk contributions are described on the basis of general plant design features relevant for risk and accident analysis. With this background, search strategies for human risk contributions are treated: Under the designation ''work analysis'', procedures for the analysis of familiar, well trained, planned tasks are proposed. Strategies for identifying human risk contributions outside this category are outlined. (author)

  10. Formalized Search Strategies for Human Risk Contributions

    DEFF Research Database (Denmark)

    Rasmussen, Jens; Pedersen, O. M.

    For risk management, the results of a probabilistic risk analysis (PRA) as well as the underlying assumptions can be used as references in a closed-loop risk control; and the analyses of operational experiences as a means of feedback. In this context, the need for explicit definition...... risk contributions are described on the basis of general plant design features relevant for risk and accident analysis. With this background, search strategies for human risk contributions are treated: Under the designation "work analysis", procedures for the analysis of familiar, well trained, planned...... tasks are proposed. Strategies for identifying human risk contributions outside this category are outlined....

  11. Organizational Search Strategy: An Examination of Interdependencies, Locus and Temporality of Search

    NARCIS (Netherlands)

    Ebrahim, Mahdi

    2017-01-01

    Notwithstanding the ample research on organizational search and its performance implications, the factors that shape the organizations’ search strategy is fairly under-explored. This study investigates how problems’ characteristics influence the managerial decision of searching jointly or

  12. Cooperative random Levy flight searches and the flight patterns of honeybees

    International Nuclear Information System (INIS)

    Reynolds, A.M.

    2006-01-01

    The most efficient Levy flight (scale-free) searching strategy for N independent searchers to adopt when target sites are randomly and sparsely distributed is identified. For N=1, it is well known that the optimal searching strategy is attained when μ=2, where the exponent μ characterizes the Levy distribution, P(l)=l -μ , of flight-lengths. For N>1, the optimal searching strategy is attained as μ->1. It is suggested that the orientation flights of honeybees can be understood within the context of such an optimal cooperative random Levy flight searching strategy. Upon returning to their hive after surveying a landscape honeybees can exchange information about the locations of target sites through the waggle dance. In accordance with observations it is predicted that the waggle dance can be disrupted without noticeable influence on a hive's ability to maintain weight when forage is plentiful

  13. Chance and strategy in search processes

    International Nuclear Information System (INIS)

    Moreau, M; Bénichou, O; Loverdo, C; Voituriez, R

    2009-01-01

    We consider a searcher in quest of a target in two situations: in the presence of an infinite number of identical, Poisson distributed targets, and in the presence of a unique target in a finite territory. The searcher alternates intensive search phases, during which it scans the neighbouring territory but does not move, and displacement phases with no target detection. We study the problem of determining the best strategy of displacement for minimizing the mean search time: either a deterministic or a stochastic trajectory. With a reasonable simplifying hypothesis, we show that for Poisson distributed targets, deterministic, self-avoiding trajectories are more efficient than stochastic ones if the detection process involves no memory skills and can be modelled by a Markov process. In contrast, if the detection process is not Markovian, it can be better for the searcher to follow a stochastic trajectory rather than a self-avoiding trajectory, and we give an explicit example of such a memory law. In the case of a unique target, self-avoiding trajectories are always better if an infinite time is available for the search, whereas stochastic trajectories can be more efficient if the searcher has to find the target before a given deadline. Moreover, we show that the gain due to a deterministic trajectory, compared to a stochastic one, is not significant in the case of a large network containing a unique target. Additionally, for various examples of displacement trajectories, we compute the overall mean search time and study its minimization as a function of the mean duration of the detection process

  14. Optimal intermittent search strategies: smelling the prey

    International Nuclear Information System (INIS)

    Revelli, J A; Wio, H S; Rojo, F; Budde, C E

    2010-01-01

    We study the kinetics of the search of a single fixed target by a searcher/walker that performs an intermittent random walk, characterized by different states of motion. In addition, we assume that the walker has the ability to detect the scent left by the prey/target in its surroundings. Our results, in agreement with intuition, indicate that the prey's survival probability could be strongly reduced (increased) if the predator is attracted (or repelled) by the trace left by the prey. We have also found that, for a positive trace (the predator is guided towards the prey), increasing the inhomogeneity's size reduces the prey's survival probability, while the optimal value of α (the parameter that regulates intermittency) ceases to exist. The agreement between theory and numerical simulations is excellent.

  15. Optimal intermittent search strategies: smelling the prey

    Energy Technology Data Exchange (ETDEWEB)

    Revelli, J A; Wio, H S [Instituto de Fisica de Cantabria, Universidad de Cantabria and CSIC, E-39005 Santander (Spain); Rojo, F; Budde, C E [Fa.M.A.F., Universidad Nacional de Cordoba, Ciudad Universitaria, X5000HUA Cordoba (Argentina)

    2010-05-14

    We study the kinetics of the search of a single fixed target by a searcher/walker that performs an intermittent random walk, characterized by different states of motion. In addition, we assume that the walker has the ability to detect the scent left by the prey/target in its surroundings. Our results, in agreement with intuition, indicate that the prey's survival probability could be strongly reduced (increased) if the predator is attracted (or repelled) by the trace left by the prey. We have also found that, for a positive trace (the predator is guided towards the prey), increasing the inhomogeneity's size reduces the prey's survival probability, while the optimal value of {alpha} (the parameter that regulates intermittency) ceases to exist. The agreement between theory and numerical simulations is excellent.

  16. Greedy Local Search and Vertex Cover in Sparse Random Graphs

    DEFF Research Database (Denmark)

    Witt, Carsten

    2009-01-01

    . This work starts with a rigorous explanation for this claim based on the refined analysis of the Karp-Sipser algorithm by Aronson et al. Subsequently, theoretical supplements are given to experimental studies of search heuristics on random graphs. For c 1, a greedy and randomized local-search heuristic...... finds an optimal cover in polynomial time with a probability arbitrarily close to 1. This behavior relies on the absence of a giant component. As an additional insight into the randomized search, it is shown that the heuristic fails badly also on graphs consisting of a single tree component of maximum......Recently, various randomized search heuristics have been studied for the solution of the minimum vertex cover problem, in particular for sparse random instances according to the G(n, c/n) model, where c > 0 is a constant. Methods from statistical physics suggest that the problem is easy if c

  17. Theory of Randomized Search Heuristics in Combinatorial Optimization

    DEFF Research Database (Denmark)

    The rigorous mathematical analysis of randomized search heuristics(RSHs) with respect to their expected runtime is a growing research area where many results have been obtained in recent years. This class of heuristics includes well-known approaches such as Randomized Local Search (RLS), the Metr......The rigorous mathematical analysis of randomized search heuristics(RSHs) with respect to their expected runtime is a growing research area where many results have been obtained in recent years. This class of heuristics includes well-known approaches such as Randomized Local Search (RLS...... analysis of randomized algorithms to RSHs. Mostly, the expected runtime of RSHs on selected problems is analzyed. Thereby, we understand why and when RSHs are efficient optimizers and, conversely, when they cannot be efficient. The tutorial will give an overview on the analysis of RSHs for solving...

  18. Can collective searches profit from Levy walk strategies?

    Energy Technology Data Exchange (ETDEWEB)

    Santos, M C; Da Luz, M G E [Departamento de Fisica, Universidade Federal do Parana, Curitiba-PR, 81531-990 (Brazil); Raposo, E P [Laboratorio de Fisica Teorica e Computacional, Departamento de Fisica, Universidade Federal de Pernambuco, Recife-PE, 50670-901 (Brazil); Viswanathan, G M [Instituto de Fisica, Universidade Federal de Alagoas, Maceio-AL, 57072-970 (Brazil)], E-mail: luz@fisica.ufpr.br

    2009-10-30

    We address the problem of collective searching in which a group of walkers, guided by a leader, looks for randomly located target sites. In such a process, the necessity to maintain the group aggregated imposes a constraint in the foraging dynamics. We discuss four different models for the system collective behavior, with the leader and followers performing Gaussian as well as truncated Levy walks. In environments with low density of targets we show that Levy foraging is advantageous for the whole group, when compared with Gaussian strategy. Furthermore, certain extra rules must be incorporated in the individuals' dynamics, so that a compromise between the trend to keep the group together and the global efficiency of search is met. The exact character of these rules depends on specific details of the foraging process, such as regeneration of target sites and energy costs.

  19. Scattering quantum random-walk search with errors

    International Nuclear Information System (INIS)

    Gabris, A.; Kiss, T.; Jex, I.

    2007-01-01

    We analyze the realization of a quantum-walk search algorithm in a passive, linear optical network. The specific model enables us to consider the effect of realistic sources of noise and losses on the search efficiency. Photon loss uniform in all directions is shown to lead to the rescaling of search time. Deviation from directional uniformity leads to the enhancement of the search efficiency compared to uniform loss with the same average. In certain cases even increasing loss in some of the directions can improve search efficiency. We show that while we approach the classical limit of the general search algorithm by introducing random phase fluctuations, its utility for searching is lost. Using numerical methods, we found that for static phase errors the averaged search efficiency displays a damped oscillatory behavior that asymptotically tends to a nonzero value

  20. Web-based information search and retrieval: effects of strategy use and age on search success.

    Science.gov (United States)

    Stronge, Aideen J; Rogers, Wendy A; Fisk, Arthur D

    2006-01-01

    The purpose of this study was to investigate the relationship between strategy use and search success on the World Wide Web (i.e., the Web) for experienced Web users. An additional goal was to extend understanding of how the age of the searcher may influence strategy use. Current investigations of information search and retrieval on the Web have provided an incomplete picture of Web strategy use because participants have not been given the opportunity to demonstrate their knowledge of Web strategies while also searching for information on the Web. Using both behavioral and knowledge-engineering methods, we investigated searching behavior and system knowledge for 16 younger adults (M = 20.88 years of age) and 16 older adults (M = 67.88 years). Older adults were less successful than younger adults in finding correct answers to the search tasks. Knowledge engineering revealed that the age-related effect resulted from ineffective search strategies and amount of Web experience rather than age per se. Our analysis led to the development of a decision-action diagram representing search behavior for both age groups. Older adults had more difficulty than younger adults when searching for information on the Web. However, this difficulty was related to the selection of inefficient search strategies, which may have been attributable to a lack of knowledge about available Web search strategies. Actual or potential applications of this research include training Web users to search more effectively and suggestions to improve the design of search engines.

  1. An adaptive random search for short term generation scheduling with network constraints.

    Directory of Open Access Journals (Sweden)

    J A Marmolejo

    Full Text Available This paper presents an adaptive random search approach to address a short term generation scheduling with network constraints, which determines the startup and shutdown schedules of thermal units over a given planning horizon. In this model, we consider the transmission network through capacity limits and line losses. The mathematical model is stated in the form of a Mixed Integer Non Linear Problem with binary variables. The proposed heuristic is a population-based method that generates a set of new potential solutions via a random search strategy. The random search is based on the Markov Chain Monte Carlo method. The main key of the proposed method is that the noise level of the random search is adaptively controlled in order to exploring and exploiting the entire search space. In order to improve the solutions, we consider coupling a local search into random search process. Several test systems are presented to evaluate the performance of the proposed heuristic. We use a commercial optimizer to compare the quality of the solutions provided by the proposed method. The solution of the proposed algorithm showed a significant reduction in computational effort with respect to the full-scale outer approximation commercial solver. Numerical results show the potential and robustness of our approach.

  2. Decoherence in optimized quantum random-walk search algorithm

    International Nuclear Information System (INIS)

    Zhang Yu-Chao; Bao Wan-Su; Wang Xiang; Fu Xiang-Qun

    2015-01-01

    This paper investigates the effects of decoherence generated by broken-link-type noise in the hypercube on an optimized quantum random-walk search algorithm. When the hypercube occurs with random broken links, the optimized quantum random-walk search algorithm with decoherence is depicted through defining the shift operator which includes the possibility of broken links. For a given database size, we obtain the maximum success rate of the algorithm and the required number of iterations through numerical simulations and analysis when the algorithm is in the presence of decoherence. Then the computational complexity of the algorithm with decoherence is obtained. The results show that the ultimate effect of broken-link-type decoherence on the optimized quantum random-walk search algorithm is negative. (paper)

  3. Effects of a random noisy oracle on search algorithm complexity

    International Nuclear Information System (INIS)

    Shenvi, Neil; Brown, Kenneth R.; Whaley, K. Birgitta

    2003-01-01

    Grover's algorithm provides a quadratic speed-up over classical algorithms for unstructured database or library searches. This paper examines the robustness of Grover's search algorithm to a random phase error in the oracle and analyzes the complexity of the search process as a function of the scaling of the oracle error with database or library size. Both the discrete- and continuous-time implementations of the search algorithm are investigated. It is shown that unless the oracle phase error scales as O(N -1/4 ), neither the discrete- nor the continuous-time implementation of Grover's algorithm is scalably robust to this error in the absence of error correction

  4. Uncovering Web search strategies in South African higher education

    Directory of Open Access Journals (Sweden)

    Surika Civilcharran

    2016-11-01

    Full Text Available Background: In spite of the enormous amount of information available on the Web and the fact that search engines are continuously evolving to enhance the search experience, students are nevertheless faced with the difficulty of effectively retrieving information. It is, therefore, imperative for the interaction between students and search tools to be understood and search strategies to be identified, in order to promote successful information retrieval. Objectives: This study identifies the Web search strategies used by postgraduate students and forms part of a wider study into information retrieval strategies used by postgraduate students at the University of KwaZulu-Natal (UKZN, Pietermaritzburg campus, South Africa. Method: Largely underpinned by Thatcher’s cognitive search strategies, the mixed-methods approach was utilised for this study, in which questionnaires were employed in Phase 1 and structured interviews in Phase 2. This article reports and reflects on the findings of Phase 2, which focus on identifying the Web search strategies employed by postgraduate students. The Phase 1 results were reported in Civilcharran, Hughes and Maharaj (2015. Results: Findings reveal the Web search strategies used for academic information retrieval. In spite of easy access to the invisible Web and the advent of meta-search engines, the use of Web search engines still remains the preferred search tool. The UKZN online library databases and especially the UKZN online library, Online Public Access Catalogue system, are being underutilised. Conclusion: Being ranked in the top three percent of the world’s universities, UKZN is investing in search tools that are not being used to their full potential. This evidence suggests an urgent need for students to be trained in Web searching and to have a greater exposure to a variety of search tools. This article is intended to further contribute to the design of undergraduate training programmes in order to deal

  5. Concentrated Hitting Times of Randomized Search Heuristics with Variable Drift

    DEFF Research Database (Denmark)

    Lehre, Per Kristian; Witt, Carsten

    2014-01-01

    Drift analysis is one of the state-of-the-art techniques for the runtime analysis of randomized search heuristics (RSHs) such as evolutionary algorithms (EAs), simulated annealing etc. The vast majority of existing drift theorems yield bounds on the expected value of the hitting time for a target...

  6. Optimal random search for a single hidden target.

    Science.gov (United States)

    Snider, Joseph

    2011-01-01

    A single target is hidden at a location chosen from a predetermined probability distribution. Then, a searcher must find a second probability distribution from which random search points are sampled such that the target is found in the minimum number of trials. Here it will be shown that if the searcher must get very close to the target to find it, then the best search distribution is proportional to the square root of the target distribution regardless of dimension. For a Gaussian target distribution, the optimum search distribution is approximately a Gaussian with a standard deviation that varies inversely with how close the searcher must be to the target to find it. For a network where the searcher randomly samples nodes and looks for the fixed target along edges, the optimum is either to sample a node with probability proportional to the square root of the out-degree plus 1 or not to do so at all.

  7. Online Information Search Performance and Search Strategies in a Health Problem-Solving Scenario.

    Science.gov (United States)

    Sharit, Joseph; Taha, Jessica; Berkowsky, Ronald W; Profita, Halley; Czaja, Sara J

    2015-01-01

    Although access to Internet health information can be beneficial, solving complex health-related problems online is challenging for many individuals. In this study, we investigated the performance of a sample of 60 adults ages 18 to 85 years in using the Internet to resolve a relatively complex health information problem. The impact of age, Internet experience, and cognitive abilities on measures of search time, amount of search, and search accuracy was examined, and a model of Internet information seeking was developed to guide the characterization of participants' search strategies. Internet experience was found to have no impact on performance measures. Older participants exhibited longer search times and lower amounts of search but similar search accuracy performance as their younger counterparts. Overall, greater search accuracy was related to an increased amount of search but not to increased search duration and was primarily attributable to higher cognitive abilities, such as processing speed, reasoning ability, and executive function. There was a tendency for those who were younger, had greater Internet experience, and had higher cognitive abilities to use a bottom-up (i.e., analytic) search strategy, although use of a top-down (i.e., browsing) strategy was not necessarily unsuccessful. Implications of the findings for future studies and design interventions are discussed.

  8. ARSTEC, Nonlinear Optimization Program Using Random Search Method

    International Nuclear Information System (INIS)

    Rasmuson, D. M.; Marshall, N. H.

    1979-01-01

    1 - Description of problem or function: The ARSTEC program was written to solve nonlinear, mixed integer, optimization problems. An example of such a problem in the nuclear industry is the allocation of redundant parts in the design of a nuclear power plant to minimize plant unavailability. 2 - Method of solution: The technique used in ARSTEC is the adaptive random search method. The search is started from an arbitrary point in the search region and every time a point that improves the objective function is found, the search region is centered at that new point. 3 - Restrictions on the complexity of the problem: Presently, the maximum number of independent variables allowed is 10. This can be changed by increasing the dimension of the arrays

  9. Optimizing Event Selection with the Random Grid Search

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, Pushpalatha C. [Fermilab; Prosper, Harrison B. [Florida State U.; Sekmen, Sezen [Kyungpook Natl. U.; Stewart, Chip [Broad Inst., Cambridge

    2017-06-29

    The random grid search (RGS) is a simple, but efficient, stochastic algorithm to find optimal cuts that was developed in the context of the search for the top quark at Fermilab in the mid-1990s. The algorithm, and associated code, have been enhanced recently with the introduction of two new cut types, one of which has been successfully used in searches for supersymmetry at the Large Hadron Collider. The RGS optimization algorithm is described along with the recent developments, which are illustrated with two examples from particle physics. One explores the optimization of the selection of vector boson fusion events in the four-lepton decay mode of the Higgs boson and the other optimizes SUSY searches using boosted objects and the razor variables.

  10. Online games: a novel approach to explore how partial information influences human random searches

    Science.gov (United States)

    Martínez-García, Ricardo; Calabrese, Justin M.; López, Cristóbal

    2017-01-01

    Many natural processes rely on optimizing the success ratio of a search process. We use an experimental setup consisting of a simple online game in which players have to find a target hidden on a board, to investigate how the rounds are influenced by the detection of cues. We focus on the search duration and the statistics of the trajectories traced on the board. The experimental data are explained by a family of random-walk-based models and probabilistic analytical approximations. If no initial information is given to the players, the search is optimized for cues that cover an intermediate spatial scale. In addition, initial information about the extension of the cues results, in general, in faster searches. Finally, strategies used by informed players turn into non-stationary processes in which the length of e ach displacement evolves to show a well-defined characteristic scale that is not found in non-informed searches.

  11. Cooperative mobile agents search using beehive partitioned structure and Tabu Random search algorithm

    Science.gov (United States)

    Ramazani, Saba; Jackson, Delvin L.; Selmic, Rastko R.

    2013-05-01

    In search and surveillance operations, deploying a team of mobile agents provides a robust solution that has multiple advantages over using a single agent in efficiency and minimizing exploration time. This paper addresses the challenge of identifying a target in a given environment when using a team of mobile agents by proposing a novel method of mapping and movement of agent teams in a cooperative manner. The approach consists of two parts. First, the region is partitioned into a hexagonal beehive structure in order to provide equidistant movements in every direction and to allow for more natural and flexible environment mapping. Additionally, in search environments that are partitioned into hexagons, mobile agents have an efficient travel path while performing searches due to this partitioning approach. Second, we use a team of mobile agents that move in a cooperative manner and utilize the Tabu Random algorithm to search for the target. Due to the ever-increasing use of robotics and Unmanned Aerial Vehicle (UAV) platforms, the field of cooperative multi-agent search has developed many applications recently that would benefit from the use of the approach presented in this work, including: search and rescue operations, surveillance, data collection, and border patrol. In this paper, the increased efficiency of the Tabu Random Search algorithm method in combination with hexagonal partitioning is simulated, analyzed, and advantages of this approach are presented and discussed.

  12. Optimal Quantum Spatial Search on Random Temporal Networks.

    Science.gov (United States)

    Chakraborty, Shantanav; Novo, Leonardo; Di Giorgio, Serena; Omar, Yasser

    2017-12-01

    To investigate the performance of quantum information tasks on networks whose topology changes in time, we study the spatial search algorithm by continuous time quantum walk to find a marked node on a random temporal network. We consider a network of n nodes constituted by a time-ordered sequence of Erdös-Rényi random graphs G(n,p), where p is the probability that any two given nodes are connected: After every time interval τ, a new graph G(n,p) replaces the previous one. We prove analytically that, for any given p, there is always a range of values of τ for which the running time of the algorithm is optimal, i.e., O(sqrt[n]), even when search on the individual static graphs constituting the temporal network is suboptimal. On the other hand, there are regimes of τ where the algorithm is suboptimal even when each of the underlying static graphs are sufficiently connected to perform optimal search on them. From this first study of quantum spatial search on a time-dependent network, it emerges that the nontrivial interplay between temporality and connectivity is key to the algorithmic performance. Moreover, our work can be extended to establish high-fidelity qubit transfer between any two nodes of the network. Overall, our findings show that one can exploit temporality to achieve optimal quantum information tasks on dynamical random networks.

  13. Optimal Quantum Spatial Search on Random Temporal Networks

    Science.gov (United States)

    Chakraborty, Shantanav; Novo, Leonardo; Di Giorgio, Serena; Omar, Yasser

    2017-12-01

    To investigate the performance of quantum information tasks on networks whose topology changes in time, we study the spatial search algorithm by continuous time quantum walk to find a marked node on a random temporal network. We consider a network of n nodes constituted by a time-ordered sequence of Erdös-Rényi random graphs G (n ,p ), where p is the probability that any two given nodes are connected: After every time interval τ , a new graph G (n ,p ) replaces the previous one. We prove analytically that, for any given p , there is always a range of values of τ for which the running time of the algorithm is optimal, i.e., O (√{n }), even when search on the individual static graphs constituting the temporal network is suboptimal. On the other hand, there are regimes of τ where the algorithm is suboptimal even when each of the underlying static graphs are sufficiently connected to perform optimal search on them. From this first study of quantum spatial search on a time-dependent network, it emerges that the nontrivial interplay between temporality and connectivity is key to the algorithmic performance. Moreover, our work can be extended to establish high-fidelity qubit transfer between any two nodes of the network. Overall, our findings show that one can exploit temporality to achieve optimal quantum information tasks on dynamical random networks.

  14. Expedite random structure searching using objects from Wyckoff positions

    Science.gov (United States)

    Wang, Shu-Wei; Hsing, Cheng-Rong; Wei, Ching-Ming

    2018-02-01

    Random structure searching has been proved to be a powerful approach to search and find the global minimum and the metastable structures. A true random sampling is in principle needed yet it would be highly time-consuming and/or practically impossible to find the global minimum for the complicated systems in their high-dimensional configuration space. Thus the implementations of reasonable constraints, such as adopting system symmetries to reduce the independent dimension in structural space and/or imposing chemical information to reach and relax into low-energy regions, are the most essential issues in the approach. In this paper, we propose the concept of "object" which is either an atom or composed of a set of atoms (such as molecules or carbonates) carrying a symmetry defined by one of the Wyckoff positions of space group and through this process it allows the searching of global minimum for a complicated system to be confined in a greatly reduced structural space and becomes accessible in practice. We examined several representative materials, including Cd3As2 crystal, solid methanol, high-pressure carbonates (FeCO3), and Si(111)-7 × 7 reconstructed surface, to demonstrate the power and the advantages of using "object" concept in random structure searching.

  15. Designing Search UX Strategies for eCommerce Success

    CERN Document Server

    Nudelman, Greg

    2011-01-01

    Best practices, practical advice, and design ideas for successful ecommerce search A glaring gap has existed in the market for a resource that offers a comprehensive, actionable design patterns and design strategies for ecommerce search-but no longer. With this invaluable book, user experience designer and user researcher Greg Nudelman shares his years of experience working on popular ecommerce sites as he tackles even the most difficult ecommerce search design problems. Nudelman helps you create highly effective and intuitive ecommerce search design solutions and he takes a unique forward-thi

  16. Quasi-steady-state analysis of two-dimensional random intermittent search processes

    KAUST Repository

    Bressloff, Paul C.

    2011-06-01

    We use perturbation methods to analyze a two-dimensional random intermittent search process, in which a searcher alternates between a diffusive search phase and a ballistic movement phase whose velocity direction is random. A hidden target is introduced within a rectangular domain with reflecting boundaries. If the searcher moves within range of the target and is in the search phase, it has a chance of detecting the target. A quasi-steady-state analysis is applied to the corresponding Chapman-Kolmogorov equation. This generates a reduced Fokker-Planck description of the search process involving a nonzero drift term and an anisotropic diffusion tensor. In the case of a uniform direction distribution, for which there is zero drift, and isotropic diffusion, we use the method of matched asymptotics to compute the mean first passage time (MFPT) to the target, under the assumption that the detection range of the target is much smaller than the size of the domain. We show that an optimal search strategy exists, consistent with previous studies of intermittent search in a radially symmetric domain that were based on a decoupling or moment closure approximation. We also show how the decoupling approximation can break down in the case of biased search processes. Finally, we analyze the MFPT in the case of anisotropic diffusion and find that anisotropy can be useful when the searcher starts from a fixed location. © 2011 American Physical Society.

  17. Quasi-steady-state analysis of two-dimensional random intermittent search processes

    KAUST Repository

    Bressloff, Paul C.; Newby, Jay M.

    2011-01-01

    We use perturbation methods to analyze a two-dimensional random intermittent search process, in which a searcher alternates between a diffusive search phase and a ballistic movement phase whose velocity direction is random. A hidden target is introduced within a rectangular domain with reflecting boundaries. If the searcher moves within range of the target and is in the search phase, it has a chance of detecting the target. A quasi-steady-state analysis is applied to the corresponding Chapman-Kolmogorov equation. This generates a reduced Fokker-Planck description of the search process involving a nonzero drift term and an anisotropic diffusion tensor. In the case of a uniform direction distribution, for which there is zero drift, and isotropic diffusion, we use the method of matched asymptotics to compute the mean first passage time (MFPT) to the target, under the assumption that the detection range of the target is much smaller than the size of the domain. We show that an optimal search strategy exists, consistent with previous studies of intermittent search in a radially symmetric domain that were based on a decoupling or moment closure approximation. We also show how the decoupling approximation can break down in the case of biased search processes. Finally, we analyze the MFPT in the case of anisotropic diffusion and find that anisotropy can be useful when the searcher starts from a fixed location. © 2011 American Physical Society.

  18. Confirming preferences or collecting data? Information search strategies and romantic partner selection.

    Science.gov (United States)

    Hennessy, Michael H; Fishbein, Marty; Curtis, Brenda; Barrett, Daniel

    2008-03-01

    This article investigates two kinds of information search strategies in the context of selecting romantic partners. Confirmatory searching occurs when people ask for more information about a romantic partner in order to validate or confirm their assessment. Balanced searches are characterized by a search for risk information for partners rated as attractive and for attractiveness information about partners rated as risky in order to attain a more complete evaluation. A factorial survey computer program randomly constructed five types of partner descriptions and college-age respondents evaluated nine descriptions in terms of both health risk and romantic attractiveness outcomes. The results show little evidence of balanced search strategies: for all vignette types the respondents searched for attractiveness information. Regression analysis of the search outcomes showed no difference between males and females in the desire for attractiveness or risk information, the amount of additional information desired, or the proportion of descriptions for which more information was desired. However, an attractive physical appearance did increase the amount of additional information desired and the proportion of vignettes for which more information was desired. The results were generally inconsistent with a balanced search hypothesis; a better characterization of the respondents' strategy might be "confirmatory bias."

  19. The impact of PICO as a search strategy tool on literature search quality

    DEFF Research Database (Denmark)

    Eriksen, Mette Brandt; Frandsen, Tove Faber

    2018-01-01

    Objective: This review aimed to determine, if the use of the PICO model (Patient Intervention Comparison Outcome) as a search strategy tool affects the quality of the literature search. Methods: A comprehensive literature search was conducted in: PubMed, Embase, CINAHL, PsycInfo, Cochrane Library...... and three studies were included, data was extracted, risk of bias was assessed and a qualitative analysis was conducted. The included studies compared PICO to PIC or link to related articles in PubMed; PICOS and SPIDER. One study compared PICO to unguided searching. Due to differences in intervention...

  20. STRATEGIES IN SEARCH FOR INTERNATIONAL PARTNERSHIPS

    Directory of Open Access Journals (Sweden)

    Denise de Freitas

    Full Text Available Introduction: Internationalization is the process which integrates universal, intercultural or global dimension in a program, in this case, postgraduate. It can be understood as the process of increasing participation in international operations. Method: To offer design and motivational logistics on how to run a process of international scientific relationship. Results: It is necessary to develop several different aspects to be reached internationalization: to know the fundamentals of internationalization; to have international vision; to promote strategy for internationalization; to know the characteristics of an institutional center of internationalization; and to understand the institutional advantages of internationalization. Conclusion: Internationalization is essential to aerate the Brazilian postgraduate and not mischaracterize or weakens the process. On the contrary, it contributes to increase its vitality and capacity for innovation. Today is not possible to imagine science without internationalization.

  1. Search strategies in practice: Influence of information and task constraints.

    Science.gov (United States)

    Pacheco, Matheus M; Newell, Karl M

    2018-01-01

    The practice of a motor task has been conceptualized as a process of search through a perceptual-motor workspace. The present study investigated the influence of information and task constraints on the search strategy as reflected in the sequential relations of the outcome in a discrete movement virtual projectile task. The results showed that the relation between the changes of trial-to-trial movement outcome to performance level was dependent on the landscape of the task dynamics and the influence of inherent variability. Furthermore, the search was in a constrained parameter region of the perceptual-motor workspace that depended on the task constraints. These findings show that there is not a single function of trial-to-trial change over practice but rather that local search strategies (proportional, discontinuous, constant) adapt to the level of performance and the confluence of constraints to action. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Computational assessment of visual search strategies in volumetric medical images.

    Science.gov (United States)

    Wen, Gezheng; Aizenman, Avigael; Drew, Trafton; Wolfe, Jeremy M; Haygood, Tamara Miner; Markey, Mia K

    2016-01-01

    When searching through volumetric images [e.g., computed tomography (CT)], radiologists appear to use two different search strategies: "drilling" (restrict eye movements to a small region of the image while quickly scrolling through slices), or "scanning" (search over large areas at a given depth before moving on to the next slice). To computationally identify the type of image information that is used in these two strategies, 23 naïve observers were instructed with either "drilling" or "scanning" when searching for target T's in 20 volumes of faux lung CTs. We computed saliency maps using both classical two-dimensional (2-D) saliency, and a three-dimensional (3-D) dynamic saliency that captures the characteristics of scrolling through slices. Comparing observers' gaze distributions with the saliency maps showed that search strategy alters the type of saliency that attracts fixations. Drillers' fixations aligned better with dynamic saliency and scanners with 2-D saliency. The computed saliency was greater for detected targets than for missed targets. Similar results were observed in data from 19 radiologists who searched five stacks of clinical chest CTs for lung nodules. Dynamic saliency may be superior to the 2-D saliency for detecting targets embedded in volumetric images, and thus "drilling" may be more efficient than "scanning."

  3. Stochastic optimal foraging: tuning intensive and extensive dynamics in random searches.

    Directory of Open Access Journals (Sweden)

    Frederic Bartumeus

    Full Text Available Recent theoretical developments had laid down the proper mathematical means to understand how the structural complexity of search patterns may improve foraging efficiency. Under information-deprived scenarios and specific landscape configurations, Lévy walks and flights are known to lead to high search efficiencies. Based on a one-dimensional comparative analysis we show a mechanism by which, at random, a searcher can optimize the encounter with close and distant targets. The mechanism consists of combining an optimal diffusivity (optimally enhanced diffusion with a minimal diffusion constant. In such a way the search dynamics adequately balances the tension between finding close and distant targets, while, at the same time, shifts the optimal balance towards relatively larger close-to-distant target encounter ratios. We find that introducing a multiscale set of reorientations ensures both a thorough local space exploration without oversampling and a fast spreading dynamics at the large scale. Lévy reorientation patterns account for these properties but other reorientation strategies providing similar statistical signatures can mimic or achieve comparable efficiencies. Hence, the present work unveils general mechanisms underlying efficient random search, beyond the Lévy model. Our results suggest that animals could tune key statistical movement properties (e.g. enhanced diffusivity, minimal diffusion constant to cope with the very general problem of balancing out intensive and extensive random searching. We believe that theoretical developments to mechanistically understand stochastic search strategies, such as the one here proposed, are crucial to develop an empirically verifiable and comprehensive animal foraging theory.

  4. Optimization by GRASP greedy randomized adaptive search procedures

    CERN Document Server

    Resende, Mauricio G C

    2016-01-01

    This is the first book to cover GRASP (Greedy Randomized Adaptive Search Procedures), a metaheuristic that has enjoyed wide success in practice with a broad range of applications to real-world combinatorial optimization problems. The state-of-the-art coverage and carefully crafted pedagogical style lends this book highly accessible as an introductory text not only to GRASP, but also to combinatorial optimization, greedy algorithms, local search, and path-relinking, as well as to heuristics and metaheuristics, in general. The focus is on algorithmic and computational aspects of applied optimization with GRASP with emphasis given to the end-user, providing sufficient information on the broad spectrum of advances in applied optimization with GRASP. For the more advanced reader, chapters on hybridization with path-relinking and parallel and continuous GRASP present these topics in a clear and concise fashion. Additionally, the book offers a very complete annotated bibliography of GRASP and combinatorial optimizat...

  5. A search strategy for occupational health intervention studies

    NARCIS (Netherlands)

    Verbeek, J.; Salmi, J.; Pasternack, I.; Jauhiainen, M.; Laamanen, I.; Schaafsma, F.; Hulshof, C.; van Dijk, F.

    2005-01-01

    As a result of low numbers and diversity in study type, occupational health intervention studies are not easy to locate in electronic literature databases. To develop a search strategy that facilitates finding occupational health intervention studies in Medline, both for researchers and

  6. A Competitive and Experiential Assignment in Search Engine Optimization Strategy

    Science.gov (United States)

    Clarke, Theresa B.; Clarke, Irvine, III

    2014-01-01

    Despite an increase in ad spending and demand for employees with expertise in search engine optimization (SEO), methods for teaching this important marketing strategy have received little coverage in the literature. Using Bloom's cognitive goals hierarchy as a framework, this experiential assignment provides a process for educators who may be new…

  7. The Development of Visual Search Strategies in Biscriptal Readers.

    Science.gov (United States)

    Liow, Susan Rikard; Green, David; Tam, Melissa

    1999-01-01

    To test whether cognitive processing in bilingual depends on script combinations and language proficiency, this study investigated the development of alphabetic and logographic visual search strategies in two kinds of biscriptals: (1) Malay-English and (2) Chinese-English readers. Results support the view that there are script implications of…

  8. Improved quantum-behaved particle swarm optimization with local search strategy

    Directory of Open Access Journals (Sweden)

    Maolong Xi

    2017-03-01

    Full Text Available Quantum-behaved particle swarm optimization, which was motivated by analysis of particle swarm optimization and quantum system, has shown compared performance in finding the optimal solutions for many optimization problems to other evolutionary algorithms. To address the problem of premature, a local search strategy is proposed to improve the performance of quantum-behaved particle swarm optimization. In proposed local search strategy, a super particle is presented which is a collection body of randomly selected particles’ dimension information in the swarm. The selected probability of particles in swarm is different and determined by their fitness values. To minimization problems, the fitness value of one particle is smaller; the selected probability is more and will contribute more information in constructing the super particle. In addition, in order to investigate the influence on algorithm performance with different local search space, four methods of computing the local search radius are applied in local search strategy and propose four variants of local search quantum-behaved particle swarm optimization. Empirical studies on a suite of well-known benchmark functions are undertaken in order to make an overall performance comparison among the proposed methods and other quantum-behaved particle swarm optimization. The simulation results show that the proposed quantum-behaved particle swarm optimization variants have better advantages over the original quantum-behaved particle swarm optimization.

  9. PubMed searches: overview and strategies for clinicians.

    Science.gov (United States)

    Lindsey, Wesley T; Olin, Bernie R

    2013-04-01

    PubMed is a biomedical and life sciences database maintained by a division of the National Library of Medicine known as the National Center for Biotechnology Information (NCBI). It is a large resource with more than 5600 journals indexed and greater than 22 million total citations. Searches conducted in PubMed provide references that are more specific for the intended topic compared with other popular search engines. Effective PubMed searches allow the clinician to remain current on the latest clinical trials, systematic reviews, and practice guidelines. PubMed continues to evolve by allowing users to create a customized experience through the My NCBI portal, new arrangements and options in search filters, and supporting scholarly projects through exportation of citations to reference managing software. Prepackaged search options available in the Clinical Queries feature also allow users to efficiently search for clinical literature. PubMed also provides information regarding the source journals themselves through the Journals in NCBI Databases link. This article provides an overview of the PubMed database's structure and features as well as strategies for conducting an effective search.

  10. Strategies to optimize MEDLINE and EMBASE search strategies for anesthesiology systematic reviews. An experimental study.

    Science.gov (United States)

    Volpato, Enilze de Souza Nogueira; Betini, Marluci; Puga, Maria Eduarda; Agarwal, Arnav; Cataneo, Antônio José Maria; Oliveira, Luciane Dias de; Bazan, Rodrigo; Braz, Leandro Gobbo; Pereira, José Eduardo Guimarães; El Dib, Regina

    2018-01-15

    A high-quality electronic search is essential for ensuring accuracy and comprehensiveness among the records retrieved when conducting systematic reviews. Therefore, we aimed to identify the most efficient method for searching in both MEDLINE (through PubMed) and EMBASE, covering search terms with variant spellings, direct and indirect orders, and associations with MeSH and EMTREE terms (or lack thereof). Experimental study. UNESP, Brazil. We selected and analyzed 37 search strategies that had specifically been developed for the field of anesthesiology. These search strategies were adapted in order to cover all potentially relevant search terms, with regard to variant spellings and direct and indirect orders, in the most efficient manner. When the strategies included variant spellings and direct and indirect orders, these adapted versions of the search strategies selected retrieved the same number of search results in MEDLINE (mean of 61.3%) and a higher number in EMBASE (mean of 63.9%) in the sample analyzed. The numbers of results retrieved through the searches analyzed here were not identical with and without associated use of MeSH and EMTREE terms. However, association of these terms from both controlled vocabularies retrieved a larger number of records than did the use of either one of them. In view of these results, we recommend that the search terms used should include both preferred and non-preferred terms (i.e. variant spellings and direct/indirect order of the same term) and associated MeSH and EMTREE terms, in order to develop highly-sensitive search strategies for systematic reviews.

  11. Searching for evidence: Knowledge and search strategies used by forensic scientists

    NARCIS (Netherlands)

    Schraagen, J.M.C.; Leijenhorst, H.

    2001-01-01

    The Forensic Science Laboratory of The Netherlands is suffering from a growing backlog due to an increasing number of cases, which results in long delivery times of research reports within a number of departments. The project, "Strategies for Searching Trace Evidence," was started by the Forensic

  12. Search strategies on the Internet: general and specific.

    Science.gov (United States)

    Bottrill, Krys

    2004-06-01

    Some of the most up-to-date information on scientific activity is to be found on the Internet; for example, on the websites of academic and other research institutions and in databases of currently funded research studies provided on the websites of funding bodies. Such information can be valuable in suggesting new approaches and techniques that could be applicable in a Three Rs context. However, the Internet is a chaotic medium, not subject to the meticulous classification and organisation of classical information resources. At the same time, Internet search engines do not match the sophistication of search systems used by database hosts. Also, although some offer relatively advanced features, user awareness of these tends to be low. Furthermore, much of the information on the Internet is not accessible to conventional search engines, giving rise to the concept of the "Invisible Web". General strategies and techniques for Internet searching are presented, together with a comparative survey of selected search engines. The question of how the Invisible Web can be accessed is discussed, as well as how to keep up-to-date with Internet content and improve searching skills.

  13. Search strategy for theorem proving in artificial systems. II

    Energy Technology Data Exchange (ETDEWEB)

    Lovitskii, V A; Barenboim, M S

    1981-01-01

    For Pt.I see IBID., p.28 (1981). An algorithm is presented, realizing the strategy of part I, by constructing a graph of disproofs. The idea central to the algorithm is to choose pairs of literals with the highest probability at the given moment, rather than to choose literals at random. 3 references.

  14. Global Search Strategies for Solving Multilinear Least-Squares Problems

    Directory of Open Access Journals (Sweden)

    Mats Andersson

    2012-04-01

    Full Text Available The multilinear least-squares (MLLS problem is an extension of the linear least-squares problem. The difference is that a multilinear operator is used in place of a matrix-vector product. The MLLS is typically a large-scale problem characterized by a large number of local minimizers. It originates, for instance, from the design of filter networks. We present a global search strategy that allows for moving from one local minimizer to a better one. The efficiency of this strategy is illustrated by the results of numerical experiments performed for some problems related to the design of filter networks.

  15. Enhancing Islamic Students’ Reading Comprehension through Predict Organize Search Summarize Evaluate Strategy

    Directory of Open Access Journals (Sweden)

    Darmayenti Darmayenti

    2017-02-01

    Full Text Available This paper is a report of an experimental research project conducted in a reading comprehension course for first-year students of the Adab Faculty of the State Institute for Islamic Studies Imam Bonjol Padang, West Sumatera, Indonesia, during the academic year 2015/2016. The “Predict Organize Search Summarize Evaluate” (POSSE is one strategy that can enhance students’ comprehension in reading. Two classes of Arabic and History students chosen through cluster random sampling technique were used as the sample of the research. Reading tests were used to collect the data which was given to both of classes on pre-test and post-test. The result of the research showed that the implementation of Predict Organize Search Summarize Evaluate strategy gave a significant difference in term of the students-learning outcome between the students who were taught through POSSE strategy and by traditional one. The finding of the study showed that teaching reading by using POSSE strategy gave significant effect towards students’ reading comprehension. This strategy could improve the students’ reading component on finding topic. It can be concluded that using POSSE Strategy has improved Indonesian students’ reading comprehension. It is also recommended for English lecturers use POSSE strategy as one of teaching strategies for reading comprehension.

  16. Strategies to improve sleep during extended search and rescue operations.

    Science.gov (United States)

    Jenkins, Jennifer Lee; Fredericksen, Kim; Stone, Roger; Tang, Nelson

    2007-01-01

    This study investigated strategies to improve sleeping conditions during search and rescue operations during disaster response. Forty members of the Montgomery County (Maryland) Urban Search and Rescue Team were surveyed for individual sleep habits and sleeping aids used during extended deployments. Team members were also asked to suggest methods to improve sleep on future deployments. The average amount of sleep during field operations was 5.4 hours with a range of 4-8 hours. Eight percent surveyed would prefer another schedule besides the 12-hour work day, all of whom proposed three 8-hour shifts. Fifteen percent of participants were interested in a pharmacological sleeping aid. Fifty percent of search and rescue members interviewed would consider using nonpharmacological sleeping aids. Furthermore, 40% of participants stated they had successfully devised self-employed methods of sleep aids for previous deployments, such as ear plugs, massage, mental imagery, personal routines, music and headphones, reading, and blindfolds. This study suggests that availability of both pharmacological and nonpharmacological sleeping aids to search and rescue workers via the team cache could impact the quantity of sleep. Further investigation into methods of optimizing sleep during field missions could theoretically show enhanced performance through various aspects of missions including mitigation of errors, improved productivity, and improved overall physiological and emotional well-being of search and rescue personnel.

  17. Motile male gametes of the araphid diatom Tabularia fasciculata search randomly for mates.

    Directory of Open Access Journals (Sweden)

    Robyn Edgar

    Full Text Available Sexuality in the marine araphid diatom Tabularia involves an unusual type of gamete, not only among diatoms but possibly in all of nature. The non-flagellated male gamete is free and vigorously motile, propelled by pseudopodia. However, the cues (if any in their search for compatible female gametes and the general search patterns to locate them are unknown. We tracked and compared male gamete movements in the presence and absence of receptive female gametes. Path linearity of male movement was not affected by presence of female gametes. Male gametes did not move towards female gametes regardless of their proximity to each other, suggesting that the detection range for a compatible mate is very small compared to known algal examples (mostly spermatozoids and that mate recognition requires (near contact with a female gamete. We therefore investigated how male gametes move to bring insight into their search strategy and found that it was consistent with the predictions of a random-walk model with changes in direction coming from an even distribution. We further investigated the type of random walk by determining the best-fit distribution on the tail of the move length distribution and found it to be consistent with a truncated power law distribution with an exponent of 2.34. Although consistent with a Lévy walk search pattern, the range of move lengths in the tail was too narrow for Lévy properties to emerge and so would be best described as Brownian motion. This is somewhat surprising because female gametes were often outnumbered by male gametes, thus contrary to the assumption that a Brownian search mode may be most optimal with an abundant target resource. This is also the first mathematically analysed search pattern of a non-flagellated protistan gamete, supporting the notion that principles of Brownian motion have wide application in biology.

  18. In Search of Search Engine Marketing Strategy Amongst SME's in Ireland

    Science.gov (United States)

    Barry, Chris; Charleton, Debbie

    Researchers have identified the Web as a searchers first port of call for locating information. Search Engine Marketing (SEM) strategies have been noted as a key consideration when developing, maintaining and managing Websites. A study presented here of SEM practices of Irish small to medium enterprises (SMEs) reveals they plan to spend more resources on SEM in the future. Most firms utilize an informal SEM strategy, where Website optimization is perceived most effective in attracting traffic. Respondents cite the use of ‘keywords in title and description tags’ as the most used SEM technique, followed by the use of ‘keywords throughout the whole Website’; while ‘Pay for Placement’ was most widely used Paid Search technique. In concurrence with the literature, measuring SEM performance remains a significant challenge with many firms unsure if they measure it effectively. An encouraging finding is that Irish SMEs adopt a positive ethical posture when undertaking SEM.

  19. Galaxy Strategy for Ligo-Virgo Gravitational Wave Counterpart Searches

    Science.gov (United States)

    Gehrels, Neil; Cannizzo, John K.; Kanner, Jonah; Kasliwal, Mansi M.; Nissanke, Samaya; Singer, Leo P.

    2016-01-01

    In this work we continue a line of inquiry begun in Kanner et al. which detailed a strategy for utilizing telescopes with narrow fields of view, such as the Swift X-Ray Telescope (XRT), to localize gravity wave (GW) triggers from LIGO (Laser Interferometer Gravitational-Wave Observatory) / Virgo. If one considers the brightest galaxies that produce 50 percent of the light, then the number of galaxies inside typical GW error boxes will be several tens. We have found that this result applies both in the early years of Advanced LIGO when the range is small and the error boxes large, and in the later years when the error boxes will be small and the range large. This strategy has the beneficial property of reducing the number of telescope pointings by a factor 10 to 100 compared with tiling the entire error box. Additional galaxy count reduction will come from a GW rapid distance estimate which will restrict the radial slice in search volume. Combining the bright galaxy strategy with a convolution based on anticipated GW localizations, we find that the searches can be restricted to about 18 plus or minus 5 galaxies for 2015, about 23 plus or minus 4 for 2017, and about 11 plus or minus for 2020. This assumes a distance localization at the putative neutron star-neutron star (NS-NS) merger range mu for each target year, and these totals are integrated out to the range. Integrating out to the horizon would roughly double the totals. For localizations with r (rotation) greatly less than mu the totals would decrease. The galaxy strategy we present in this work will enable numerous sensitive optical and X-ray telescopes with small fields of view to participate meaningfully in searches wherein the prospects for rapidly fading afterglow place a premium on a fast response time.

  20. Optimal swimming strategies in mate searching pelagic copepods

    DEFF Research Database (Denmark)

    Kiørboe, Thomas

    2008-01-01

    Male copepods must swim to find females, but swimming increases the risk of meeting predators and is expensive in terms of energy expenditure. Here I address the trade-offs between gains and risks and the question of how much and how fast to swim using simple models that optimise the number...... of lifetime mate encounters. Radically different swimming strategies are predicted for different feeding behaviours, and these predictions are tested experimentally using representative species. In general, male swimming speeds and the difference in swimming speeds between the genders are predicted...... and observed to increase with increasing conflict between mate searching and feeding. It is high in ambush feeders, where searching (swimming) and feeding are mutually exclusive and low in species, where the matured males do not feed at all. Ambush feeding males alternate between stationary ambush feeding...

  1. Randomized Strategies for the Plurality Problem

    Czech Academy of Sciences Publication Activity Database

    Král´, D.; Tichý, T.; Sgall, Jiří

    2008-01-01

    Roč. 156, č. 17 (2008), s. 3305-3311 ISSN 0166-218X R&D Projects: GA ČR GA201/05/0124 Institutional research plan: CEZ:AV0Z10190503 Keywords : concrete complexity * randomized algorithms Subject RIV: BA - General Mathematics Impact factor: 0.783, year: 2008

  2. Expected Fitness Gains of Randomized Search Heuristics for the Traveling Salesperson Problem.

    Science.gov (United States)

    Nallaperuma, Samadhi; Neumann, Frank; Sudholt, Dirk

    2017-01-01

    Randomized search heuristics are frequently applied to NP-hard combinatorial optimization problems. The runtime analysis of randomized search heuristics has contributed tremendously to our theoretical understanding. Recently, randomized search heuristics have been examined regarding their achievable progress within a fixed-time budget. We follow this approach and present a fixed-budget analysis for an NP-hard combinatorial optimization problem. We consider the well-known Traveling Salesperson Problem (TSP) and analyze the fitness increase that randomized search heuristics are able to achieve within a given fixed-time budget. In particular, we analyze Manhattan and Euclidean TSP instances and Randomized Local Search (RLS), (1+1) EA and (1+[Formula: see text]) EA algorithms for the TSP in a smoothed complexity setting, and derive the lower bounds of the expected fitness gain for a specified number of generations.

  3. An Improved Harmony Search Based on Teaching-Learning Strategy for Unconstrained Optimization Problems

    Directory of Open Access Journals (Sweden)

    Shouheng Tuo

    2013-01-01

    Full Text Available Harmony search (HS algorithm is an emerging population-based metaheuristic algorithm, which is inspired by the music improvisation process. The HS method has been developed rapidly and applied widely during the past decade. In this paper, an improved global harmony search algorithm, named harmony search based on teaching-learning (HSTL, is presented for high dimension complex optimization problems. In HSTL algorithm, four strategies (harmony memory consideration, teaching-learning strategy, local pitch adjusting, and random mutation are employed to maintain the proper balance between convergence and population diversity, and dynamic strategy is adopted to change the parameters. The proposed HSTL algorithm is investigated and compared with three other state-of-the-art HS optimization algorithms. Furthermore, to demonstrate the robustness and convergence, the success rate and convergence analysis is also studied. The experimental results of 31 complex benchmark functions demonstrate that the HSTL method has strong convergence and robustness and has better balance capacity of space exploration and local exploitation on high dimension complex optimization problems.

  4. Efficient sampling of complex network with modified random walk strategies

    Science.gov (United States)

    Xie, Yunya; Chang, Shuhua; Zhang, Zhipeng; Zhang, Mi; Yang, Lei

    2018-02-01

    We present two novel random walk strategies, choosing seed node (CSN) random walk and no-retracing (NR) random walk. Different from the classical random walk sampling, the CSN and NR strategies focus on the influences of the seed node choice and path overlap, respectively. Three random walk samplings are applied in the Erdös-Rényi (ER), Barabási-Albert (BA), Watts-Strogatz (WS), and the weighted USAir networks, respectively. Then, the major properties of sampled subnets, such as sampling efficiency, degree distributions, average degree and average clustering coefficient, are studied. The similar conclusions can be reached with these three random walk strategies. Firstly, the networks with small scales and simple structures are conducive to the sampling. Secondly, the average degree and the average clustering coefficient of the sampled subnet tend to the corresponding values of original networks with limited steps. And thirdly, all the degree distributions of the subnets are slightly biased to the high degree side. However, the NR strategy performs better for the average clustering coefficient of the subnet. In the real weighted USAir networks, some obvious characters like the larger clustering coefficient and the fluctuation of degree distribution are reproduced well by these random walk strategies.

  5. Testing the effectiveness of simplified search strategies for updating systematic reviews.

    Science.gov (United States)

    Rice, Maureen; Ali, Muhammad Usman; Fitzpatrick-Lewis, Donna; Kenny, Meghan; Raina, Parminder; Sherifali, Diana

    2017-08-01

    The objective of the study was to test the overall effectiveness of a simplified search strategy (SSS) for updating systematic reviews. We identified nine systematic reviews undertaken by our research group for which both comprehensive and SSS updates were performed. Three relevant performance measures were estimated, that is, sensitivity, precision, and number needed to read (NNR). The update reference searches for all nine included systematic reviews identified a total of 55,099 citations that were screened resulting in final inclusion of 163 randomized controlled trials. As compared with reference search, the SSS resulted in 8,239 hits and had a median sensitivity of 83.3%, while precision and NNR were 4.5 times better. During analysis, we found that the SSS performed better for clinically focused topics, with a median sensitivity of 100% and precision and NNR 6 times better than for the reference searches. For broader topics, the sensitivity of the SSS was 80% while precision and NNR were 5.4 times better compared with reference search. SSS performed well for clinically focused topics and, with a median sensitivity of 100%, could be a viable alternative to a conventional comprehensive search strategy for updating this type of systematic reviews particularly considering the budget constraints and the volume of new literature being published. For broader topics, 80% sensitivity is likely to be considered too low for a systematic review update in most cases, although it might be acceptable if updating a scoping or rapid review. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. CALL FOR PAPERS: Special issue on the random search problem: trends and perspectives

    Science.gov (United States)

    da Luz, Marcos G. E.; Grosberg, Alexander Y.; Raposo, Ernesto P.; Viswanathan, Gandhi M.

    2008-11-01

    This is a call for contributions to a special issue of Journal of Physics A: Mathematical and Theoretical dedicated to the subject of the random search problem. The motivation behind this special issue is to summarize in a single comprehensive publication, the main aspects (past and present), latest developments, different viewpoints and the directions being followed in this multidisciplinary field. We hope that such a special issue could become a particularly valuable reference for the broad scientific community working with the general random search problem. The Editorial Board has invited Marcos G E da Luz, Alexander Y Grosberg, Ernesto P Raposo and Gandhi M Viswanathan to serve as Guest Editors for the special issue. The general question of how to optimize the search for specific target objects in either continuous or discrete environments when the information available is limited is of significant importance in a broad range of fields. Representative examples include ecology (animal foraging, dispersion of populations), geology (oil recovery from mature reservoirs), information theory (automated researchers of registers in high-capacity database), molecular biology (proteins searching for their sites, e.g., on DNA ), etc. One reason underlying the richness of the random search problem relates to the `ignorance' of the locations of the randomly located `targets'. A statistical approach to the search problem can deal adequately with incomplete information and so stochastic strategies become advantageous. The general problem of how to search efficiently for randomly located target sites can thus be quantitatively described using the concepts and methods of statistical physics and stochastic processes. Scope Thus far, to the best of our knowledge, no recent textbook or review article in a physics journal has appeared on this topic. This makes a special issue with review and research articles attractive to those interested in acquiring a general introduction to the

  7. Two Complementary Strategies for New Physics Searches at Lepton Colliders

    Energy Technology Data Exchange (ETDEWEB)

    Hooberman, Benjamin Henry [Univ. of California, Berkeley, CA (United States)

    2009-07-06

    In this thesis I present two complementary strategies for probing beyond-the-Standard Model physics using data collected in e+e- collisions at lepton colliders. One strategy involves searching for effects at low energy mediated by new particles at the TeV mass scale, at which new physics is expected to manifest. Several new physics scenarios, including Supersymmetry and models with leptoquarks or compositeness, may lead to observable rates for charged lepton-flavor violating processes, which are forbidden in the Standard Model. I present a search for lepton-flavor violating decays of the Υ(3S) using data collected with the BABAR detector. This study establishes the 90% confidence level upper limits BF(Υ(3S) → eτ) < 5.0 x 10-6 and BF(Υ(3S) → μτ) < 4.1 x 10-6 which are used to place constraints on new physics contributing to lepton-flavor violation at the TeV mass scale. An alternative strategy is to increase the collision energy above the threshold for new particles and produce them directly. I discuss research and development efforts aimed at producing a vertex tracker which achieves the physics performance required of a high energy lepton collider. A small-scale vertex tracker prototype is constructed using Silicon sensors of 50 μm thickness and tested using charged particle beams. This tracker achieves the targeted impact parameter resolution of σLP = (5⊕10 GeV/pT) as well as a longitudinal vertex resolution of (260 ± 10) μm, which is consistent with the requirements of a TeV-scale lepton collider. This detector research and development effort must be motivated and directed by simulation studies of physics processes. Investigation of a dark matter-motivated Supersymmetry scenario is presented, in which the dark matter is composed of Supersymmetric neutralinos. In this scenario, studies of the e+e- → H0A0 production process allow for

  8. Search Engine Marketing (SEM: Financial & Competitive Advantages of an Effective Hotel SEM Strategy

    Directory of Open Access Journals (Sweden)

    Leora Halpern Lanz

    2015-05-01

    Full Text Available Search Engine Marketing and Optimization (SEO, SEM are keystones of a hotels marketing strategy, in fact research shows that 90% of travelers start their vacation planning with a Google search. Learn five strategies that can enhance a hotels SEO and SEM strategies to boost bookings.

  9. Search Engine Marketing (SEM): Financial & Competitive Advantages of an Effective Hotel SEM Strategy

    OpenAIRE

    Leora Halpern Lanz

    2015-01-01

    Search Engine Marketing and Optimization (SEO, SEM) are keystones of a hotels marketing strategy, in fact research shows that 90% of travelers start their vacation planning with a Google search. Learn five strategies that can enhance a hotels SEO and SEM strategies to boost bookings.

  10. Search for a perfect generator of random numbers

    International Nuclear Information System (INIS)

    Musyck, E.

    1977-01-01

    Theoretical tests have been carried out by COVEYOU and MAC PHERSON to verify the applications of the LEHMER algorithm. In a similar way, a theoretical method is proposed to evaluate in a rigorous way the random character of numbers generated by a shift register. This theory introduces the concept of ''degree of randomness'' of the elements, taken in a definite order, of a shift register. It permits making the judicious choice of the elements of the shift register which will produce the bits of the random numbers. On the other hand, a calculation method is developed in order to verify the primitive character of any shift register of high complexity. A new test, called ''slice test'', of empirical and theoretical use is also described; it constitutes a significant contribution to the understanding of certain properties of pseudo-random sequences. As a practical example, a random number generator structure formed with 32 bits, built out of a shift register with 61 elements and 60 modulo-2 adder circuits was made. The author is convinced that this generator can be considered to be practically perfect for all empirical applications of random numbers, particularly for the solution of Monte-Carlo problems. (author)

  11. Improving Search Strategies of Auditors – A Focus Group on Reflection Interventions

    OpenAIRE

    Fessl, Angela; Pammer, Viktoria; Wiese, Michael; Thalmann, Stefan

    2017-01-01

    Financial auditors routinely search internal as well as public knowledge bases as part of the auditing process. Efficient search strategies are crucial for knowledge workers in general and for auditors in particular. Modern search technology quickly evolves; and features beyond keyword search like fac-etted search or visual overview of knowledge bases like graph visualisations emerge. It is therefore desirable for auditors to learn about new innovations and to explore and experiment with such...

  12. Expert Search Strategies: The Information Retrieval Practices of Healthcare Information Professionals.

    Science.gov (United States)

    Russell-Rose, Tony; Chamberlain, Jon

    2017-10-02

    Healthcare information professionals play a key role in closing the knowledge gap between medical research and clinical practice. Their work involves meticulous searching of literature databases using complex search strategies that can consist of hundreds of keywords, operators, and ontology terms. This process is prone to error and can lead to inefficiency and bias if performed incorrectly. The aim of this study was to investigate the search behavior of healthcare information professionals, uncovering their needs, goals, and requirements for information retrieval systems. A survey was distributed to healthcare information professionals via professional association email discussion lists. It investigated the search tasks they undertake, their techniques for search strategy formulation, their approaches to evaluating search results, and their preferred functionality for searching library-style databases. The popular literature search system PubMed was then evaluated to determine the extent to which their needs were met. The 107 respondents indicated that their information retrieval process relied on the use of complex, repeatable, and transparent search strategies. On average it took 60 minutes to formulate a search strategy, with a search task taking 4 hours and consisting of 15 strategy lines. Respondents reviewed a median of 175 results per search task, far more than they would ideally like (100). The most desired features of a search system were merging search queries and combining search results. Healthcare information professionals routinely address some of the most challenging information retrieval problems of any profession. However, their needs are not fully supported by current literature search systems and there is demand for improved functionality, in particular regarding the development and management of search strategies. ©Tony Russell-Rose, Jon Chamberlain. Originally published in JMIR Medical Informatics (http://medinform.jmir.org), 02.10.2017.

  13. On the expected duration of a search for a fixed pattern in random data

    DEFF Research Database (Denmark)

    Nielsen, Peter Tolstrup

    1973-01-01

    An expression is obtained for the expected duration of a search to find a givenL-ary sequence in a semi-infinite stream of randomL-ary data. The search time is found to be an increasing function of the lengths of the "bifices" of the pattern, where the term bifix denotes a sequence which is both...

  14. The efficiency of different search strategies in estimating parsimony jackknife, bootstrap, and Bremer support

    Directory of Open Access Journals (Sweden)

    Müller Kai F

    2005-10-01

    Full Text Available Abstract Background For parsimony analyses, the most common way to estimate confidence is by resampling plans (nonparametric bootstrap, jackknife, and Bremer support (Decay indices. The recent literature reveals that parameter settings that are quite commonly employed are not those that are recommended by theoretical considerations and by previous empirical studies. The optimal search strategy to be applied during resampling was previously addressed solely via standard search strategies available in PAUP*. The question of a compromise between search extensiveness and improved support accuracy for Bremer support received even less attention. A set of experiments was conducted on different datasets to find an empirical cut-off point at which increased search extensiveness does not significantly change Bremer support and jackknife or bootstrap proportions any more. Results For the number of replicates needed for accurate estimates of support in resampling plans, a diagram is provided that helps to address the question whether apparently different support values really differ significantly. It is shown that the use of random addition cycles and parsimony ratchet iterations during bootstrapping does not translate into higher support, nor does any extension of the search extensiveness beyond the rather moderate effort of TBR (tree bisection and reconnection branch swapping plus saving one tree per replicate. Instead, in case of very large matrices, saving more than one shortest tree per iteration and using a strict consensus tree of these yields decreased support compared to saving only one tree. This can be interpreted as a small risk of overestimating support but should be more than compensated by other factors that counteract an enhanced type I error. With regard to Bremer support, a rule of thumb can be derived stating that not much is gained relative to the surplus computational effort when searches are extended beyond 20 ratchet iterations per

  15. Pure random search for ambient sensor distribution optimisation in a smart home environment.

    Science.gov (United States)

    Poland, Michael P; Nugent, Chris D; Wang, Hui; Chen, Liming

    2011-01-01

    Smart homes are living spaces facilitated with technology to allow individuals to remain in their own homes for longer, rather than be institutionalised. Sensors are the fundamental physical layer with any smart home, as the data they generate is used to inform decision support systems, facilitating appropriate actuator actions. Positioning of sensors is therefore a fundamental characteristic of a smart home. Contemporary smart home sensor distribution is aligned to either a) a total coverage approach; b) a human assessment approach. These methods for sensor arrangement are not data driven strategies, are unempirical and frequently irrational. This Study hypothesised that sensor deployment directed by an optimisation method that utilises inhabitants' spatial frequency data as the search space, would produce more optimal sensor distributions vs. the current method of sensor deployment by engineers. Seven human engineers were tasked to create sensor distributions based on perceived utility for 9 deployment scenarios. A Pure Random Search (PRS) algorithm was then tasked to create matched sensor distributions. The PRS method produced superior distributions in 98.4% of test cases (n=64) against human engineer instructed deployments when the engineers had no access to the spatial frequency data, and in 92.0% of test cases (n=64) when engineers had full access to these data. These results thus confirmed the hypothesis.

  16. Testing search strategies for systematic reviews in the Medline literature database through PubMed.

    Science.gov (United States)

    Volpato, Enilze S N; Betini, Marluci; El Dib, Regina

    2014-04-01

    A high-quality electronic search is essential in ensuring accuracy and completeness in retrieved records for the conducting of a systematic review. We analysed the available sample of search strategies to identify the best method for searching in Medline through PubMed, considering the use or not of parenthesis, double quotation marks, truncation and use of a simple search or search history. In our cross-sectional study of search strategies, we selected and analysed the available searches performed during evidence-based medicine classes and in systematic reviews conducted in the Botucatu Medical School, UNESP, Brazil. We analysed 120 search strategies. With regard to the use of phrase searches with parenthesis, there was no difference between the results with and without parenthesis and simple searches or search history tools in 100% of the sample analysed (P = 1.0). The number of results retrieved by the searches analysed was smaller using double quotations marks and using truncation compared with the standard strategy (P = 0.04 and P = 0.08, respectively). There is no need to use phrase-searching parenthesis to retrieve studies; however, we recommend the use of double quotation marks when an investigator attempts to retrieve articles in which a term appears to be exactly the same as what was proposed in the search form. Furthermore, we do not recommend the use of truncation in search strategies in the Medline via PubMed. Although the results of simple searches or search history tools were the same, we recommend using the latter.

  17. The development of PubMed search strategies for patient preferences for treatment outcomes

    Directory of Open Access Journals (Sweden)

    Ralph van Hoorn

    2016-07-01

    Full Text Available Abstract Background The importance of respecting patients’ preferences when making treatment decisions is increasingly recognized. Efficiently retrieving papers from the scientific literature reporting on the presence and nature of such preferences can help to achieve this goal. The objective of this study was to create a search filter for PubMed to help retrieve evidence on patient preferences for treatment outcomes. Methods A total of 27 journals were hand-searched for articles on patient preferences for treatment outcomes published in 2011. Selected articles served as a reference set. To develop optimal search strategies to retrieve this set, all articles in the reference set were randomly split into a development and a validation set. MeSH-terms and keywords retrieved using PubReMiner were tested individually and as combinations in PubMed and evaluated for retrieval performance (e.g. sensitivity (Se and specificity (Sp. Results Of 8238 articles, 22 were considered to report empirical evidence on patient preferences for specific treatment outcomes. The best search filters reached Se of 100 % [95 % CI 100-100] with Sp of 95 % [94–95 %] and Sp of 97 % [97–98 %] with 75 % Se [74–76 %]. In the validation set these queries reached values of Se of 90 % [89–91 %] with Sp 94 % [93–95 %] and Se of 80 % [79–81 %] with Sp of 97 % [96–96 %], respectively. Conclusions Narrow and broad search queries were developed which can help in retrieving literature on patient preferences for treatment outcomes. Identifying such evidence may in turn enhance the incorporation of patient preferences in clinical decision making and health technology assessment.

  18. The development of PubMed search strategies for patient preferences for treatment outcomes.

    Science.gov (United States)

    van Hoorn, Ralph; Kievit, Wietske; Booth, Andrew; Mozygemba, Kati; Lysdahl, Kristin Bakke; Refolo, Pietro; Sacchini, Dario; Gerhardus, Ansgar; van der Wilt, Gert Jan; Tummers, Marcia

    2016-07-29

    The importance of respecting patients' preferences when making treatment decisions is increasingly recognized. Efficiently retrieving papers from the scientific literature reporting on the presence and nature of such preferences can help to achieve this goal. The objective of this study was to create a search filter for PubMed to help retrieve evidence on patient preferences for treatment outcomes. A total of 27 journals were hand-searched for articles on patient preferences for treatment outcomes published in 2011. Selected articles served as a reference set. To develop optimal search strategies to retrieve this set, all articles in the reference set were randomly split into a development and a validation set. MeSH-terms and keywords retrieved using PubReMiner were tested individually and as combinations in PubMed and evaluated for retrieval performance (e.g. sensitivity (Se) and specificity (Sp)). Of 8238 articles, 22 were considered to report empirical evidence on patient preferences for specific treatment outcomes. The best search filters reached Se of 100 % [95 % CI 100-100] with Sp of 95 % [94-95 %] and Sp of 97 % [97-98 %] with 75 % Se [74-76 %]. In the validation set these queries reached values of Se of 90 % [89-91 %] with Sp 94 % [93-95 %] and Se of 80 % [79-81 %] with Sp of 97 % [96-96 %], respectively. Narrow and broad search queries were developed which can help in retrieving literature on patient preferences for treatment outcomes. Identifying such evidence may in turn enhance the incorporation of patient preferences in clinical decision making and health technology assessment.

  19. On the Runtime of Randomized Local Search and Simple Evolutionary Algorithms for Dynamic Makespan Scheduling

    DEFF Research Database (Denmark)

    Neumann, Frank; Witt, Carsten

    2015-01-01

    combinatorial optimization problem, namely makespan scheduling. We study the model of a strong adversary which is allowed to change one job at regular intervals. Furthermore, we investigate the setting of random changes. Our results show that randomized local search and a simple evolutionary algorithm are very...

  20. Lévy-taxis: a novel search strategy for finding odor plumes in turbulent flow-dominated environments

    Science.gov (United States)

    Pasternak, Zohar; Bartumeus, Frederic; Grasso, Frank W.

    2009-10-01

    Locating chemical plumes in aquatic or terrestrial environments is important for many economic, conservation, security and health related human activities. The localization process is composed mainly of two phases: finding the chemical plume and then tracking it to its source. Plume tracking has been the subject of considerable study whereas plume finding has received little attention. We address here the latter issue, where the searching agent must find the plume in a region often many times larger than the plume and devoid of the relevant chemical cues. The probability of detecting the plume not only depends on the movements of the searching agent but also on the fluid mechanical regime, shaping plume intermittency in space and time; this is a basic, general problem when exploring for ephemeral resources (e.g. moving and/or concealing targets). Here we present a bio-inspired search strategy named Lévy-taxis that, under certain conditions, located odor plumes significantly faster and with a better success rate than other search strategies such as Lévy walks (LW), correlated random walks (CRW) and systematic zig-zag. These results are based on computer simulations which contain, for the first time ever, digitalized real-world water flow and chemical plume instead of their theoretical model approximations. Combining elements of LW and CRW, Lévy-taxis is particularly efficient for searching in flow-dominated environments: it adaptively controls the stochastic search pattern using environmental information (i.e. flow) that is available throughout the course of the search and shows correlation with the source providing the cues. This strategy finds natural application in real-world search missions, both by humans and autonomous robots, since it accomodates the stochastic nature of chemical mixing in turbulent flows. In addition, it may prove useful in the field of behavioral ecology, explaining and predicting the movement patterns of various animals searching for

  1. Levy-taxis: a novel search strategy for finding odor plumes in turbulent flow-dominated environments

    International Nuclear Information System (INIS)

    Pasternak, Zohar; Grasso, Frank W; Bartumeus, Frederic

    2009-01-01

    Locating chemical plumes in aquatic or terrestrial environments is important for many economic, conservation, security and health related human activities. The localization process is composed mainly of two phases: finding the chemical plume and then tracking it to its source. Plume tracking has been the subject of considerable study whereas plume finding has received little attention. We address here the latter issue, where the searching agent must find the plume in a region often many times larger than the plume and devoid of the relevant chemical cues. The probability of detecting the plume not only depends on the movements of the searching agent but also on the fluid mechanical regime, shaping plume intermittency in space and time; this is a basic, general problem when exploring for ephemeral resources (e.g. moving and/or concealing targets). Here we present a bio-inspired search strategy named Levy-taxis that, under certain conditions, located odor plumes significantly faster and with a better success rate than other search strategies such as Levy walks (LW), correlated random walks (CRW) and systematic zig-zag. These results are based on computer simulations which contain, for the first time ever, digitalized real-world water flow and chemical plume instead of their theoretical model approximations. Combining elements of LW and CRW, Levy-taxis is particularly efficient for searching in flow-dominated environments: it adaptively controls the stochastic search pattern using environmental information (i.e. flow) that is available throughout the course of the search and shows correlation with the source providing the cues. This strategy finds natural application in real-world search missions, both by humans and autonomous robots, since it accommodates the stochastic nature of chemical mixing in turbulent flows. In addition, it may prove useful in the field of behavioral ecology, explaining and predicting the movement patterns of various animals searching for food

  2. Levy-taxis: a novel search strategy for finding odor plumes in turbulent flow-dominated environments

    Energy Technology Data Exchange (ETDEWEB)

    Pasternak, Zohar; Grasso, Frank W [BioMimetic and Cognitive Robotics Laboratory, Department of Psychology, Brooklyn College, The City University of New York, 2900 Bedford Avenue, Brooklyn 11210, NY (United States); Bartumeus, Frederic [Department of Ecology and Evolutionary Biology and Princeton Environmental Institute, 106 Guyot Hall, Princeton University, Princeton 08544, NJ (United States)], E-mail: zpast@yahoo.com

    2009-10-30

    Locating chemical plumes in aquatic or terrestrial environments is important for many economic, conservation, security and health related human activities. The localization process is composed mainly of two phases: finding the chemical plume and then tracking it to its source. Plume tracking has been the subject of considerable study whereas plume finding has received little attention. We address here the latter issue, where the searching agent must find the plume in a region often many times larger than the plume and devoid of the relevant chemical cues. The probability of detecting the plume not only depends on the movements of the searching agent but also on the fluid mechanical regime, shaping plume intermittency in space and time; this is a basic, general problem when exploring for ephemeral resources (e.g. moving and/or concealing targets). Here we present a bio-inspired search strategy named Levy-taxis that, under certain conditions, located odor plumes significantly faster and with a better success rate than other search strategies such as Levy walks (LW), correlated random walks (CRW) and systematic zig-zag. These results are based on computer simulations which contain, for the first time ever, digitalized real-world water flow and chemical plume instead of their theoretical model approximations. Combining elements of LW and CRW, Levy-taxis is particularly efficient for searching in flow-dominated environments: it adaptively controls the stochastic search pattern using environmental information (i.e. flow) that is available throughout the course of the search and shows correlation with the source providing the cues. This strategy finds natural application in real-world search missions, both by humans and autonomous robots, since it accommodates the stochastic nature of chemical mixing in turbulent flows. In addition, it may prove useful in the field of behavioral ecology, explaining and predicting the movement patterns of various animals searching for food

  3. Literature search strategies for conducting knowledge-building and theory-generating qualitative systematic reviews.

    Science.gov (United States)

    Finfgeld-Connett, Deborah; Johnson, E Diane

    2013-01-01

    To report literature search strategies for the purpose of conducting knowledge-building and theory-generating qualitative systematic reviews. Qualitative systematic reviews lie on a continuum from knowledge-building and theory-generating to aggregating and summarizing. Different types of literature searches are needed to optimally support these dissimilar reviews. Articles published between 1989-Autumn 2011. These documents were identified using a hermeneutic approach and multiple literature search strategies. Redundancy is not the sole measure of validity when conducting knowledge-building and theory-generating systematic reviews. When conducting these types of reviews, literature searches should be consistent with the goal of fully explicating concepts and the interrelationships among them. To accomplish this objective, a 'berry picking' approach is recommended along with strategies for overcoming barriers to finding qualitative research reports. To enhance integrity of knowledge-building and theory-generating systematic reviews, reviewers are urged to make literature search processes as transparent as possible, despite their complexity. This includes fully explaining and rationalizing what databases were used and how they were searched. It also means describing how literature tracking was conducted and grey literature was searched. In the end, the decision to cease searching also needs to be fully explained and rationalized. Predetermined linear search strategies are unlikely to generate search results that are adequate for purposes of conducting knowledge-building and theory-generating qualitative systematic reviews. Instead, it is recommended that iterative search strategies take shape as reviews evolve. © 2012 Blackwell Publishing Ltd.

  4. Usefulness of systematic review search strategies in finding child health systematic reviews in MEDLINE

    NARCIS (Netherlands)

    Boluyt, Nicole; Tjosvold, Lisa; Lefebvre, Carol; Klassen, Terry P.; Offringa, Martin

    2008-01-01

    OBJECTIVE: To determine the sensitivity and precision of existing search strategies for retrieving child health systematic reviews in MEDLINE using PubMed. DESIGN: Filter (diagnostic) accuracy study. We identified existing search strategies for systematic reviews, combined them with a filter that

  5. Identifying nurse staffing research in Medline: development and testing of empirically derived search strategies with the PubMed interface.

    Science.gov (United States)

    Simon, Michael; Hausner, Elke; Klaus, Susan F; Dunton, Nancy E

    2010-08-23

    The identification of health services research in databases such as PubMed/Medline is a cumbersome task. This task becomes even more difficult if the field of interest involves the use of diverse methods and data sources, as is the case with nurse staffing research. This type of research investigates the association between nurse staffing parameters and nursing and patient outcomes. A comprehensively developed search strategy may help identify nurse staffing research in PubMed/Medline. A set of relevant references in PubMed/Medline was identified by means of three systematic reviews. This development set was used to detect candidate free-text and MeSH terms. The frequency of these terms was compared to a random sample from PubMed/Medline in order to identify terms specific to nurse staffing research, which were then used to develop a sensitive, precise and balanced search strategy. To determine their precision, the newly developed search strategies were tested against a) the pool of relevant references extracted from the systematic reviews, b) a reference set identified from an electronic journal screening, and c) a sample from PubMed/Medline. Finally, all newly developed strategies were compared to PubMed's Health Services Research Queries (PubMed's HSR Queries). The sensitivities of the newly developed search strategies were almost 100% in all of the three test sets applied; precision ranged from 6.1% to 32.0%. PubMed's HSR queries were less sensitive (83.3% to 88.2%) than the new search strategies. Only minor differences in precision were found (5.0% to 32.0%). As with other literature on health services research, nurse staffing studies are difficult to identify in PubMed/Medline. Depending on the purpose of the search, researchers can choose between high sensitivity and retrieval of a large number of references or high precision, i.e. and an increased risk of missing relevant references, respectively. More standardized terminology (e.g. by consistent use of the

  6. The relationship between emotion regulation strategies and job search behavior among fourth-year university students.

    Science.gov (United States)

    Wang, Ling; Xu, Huihui; Zhang, Xue; Fang, Ping

    2017-08-01

    The job search process is a stressful experience. This study investigated the effect of emotion regulation strategies on job search behavior in combination with anxiety and job search self-efficacy among Chinese university fourth-year students (N = 816, mean age = 21.98, 31.5% male, 34.9% majored in science, 18.0% from "211 Project" universities). Results showed that cognitive reappraisal was positively related to job search behavior, while expressive suppression was negatively related to job search behavior. Additionally, anxiety was negatively related to job search behavior, while job search self-efficacy was positively associated with job search behavior. Moreover, both anxiety and job search self-efficacy mediated the relationship between emotion regulation strategies and job search behavior. In general, emotion regulation strategies played an important role in job search behavior. Implications include the notion that emotion regulation interventions may be helpful to increase job search behavior among university students. Copyright © 2017 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

  7. Search strategies for top partners in composite Higgs models

    Science.gov (United States)

    Gripaios, Ben; Müller, Thibaut; Parker, M. A.; Sutherland, Dave

    2014-08-01

    We consider how best to search for top partners in generic composite Higgs models. We begin by classifying the possible group representations carried by top partners in models with and without a custodial SU(2) × SU(2) ⋊ 2 symmetry protecting the rate for Z → decays. We identify a number of minimal models whose top partners only have electric charges of , , or and thus decay to top or bottom quarks via a single Higgs or electroweak gauge boson. We develop an inclusive search for these based on a top veto, which we find to be more effective than existing searches. Less minimal models feature light states that can be sought in final states with like-sign leptons and so we find that 2 straightforward LHC searches give a reasonable coverage of the gamut of composite Higgs models.

  8. Epidemic spreading on random surfer networks with infected avoidance strategy

    International Nuclear Information System (INIS)

    Feng Yun; Ding Li; Huang Yun-Han; Guan Zhi-Hong

    2016-01-01

    In this paper, we study epidemic spreading on random surfer networks with infected avoidance (IA) strategy. In particular, we consider that susceptible individuals’ moving direction angles are affected by the current location information received from infected individuals through a directed information network. The model is mainly analyzed by discrete-time numerical simulations. The results indicate that the IA strategy can restrain epidemic spreading effectively. However, when long-distance jumps of individuals exist, the IA strategy’s effectiveness on restraining epidemic spreading is heavily reduced. Finally, it is found that the influence of the noises from information transferring process on epidemic spreading is indistinctive. (paper)

  9. Academic Users' Information Searching on Research Topics: Characteristics of Research Tasks and Search Strategies

    Science.gov (United States)

    Du, Jia Tina; Evans, Nina

    2011-01-01

    This project investigated how academic users search for information on their real-life research tasks. This article presents the findings of the first of two studies. The study data were collected in the Queensland University of Technology (QUT) in Brisbane, Australia. Eleven PhD students' searching behaviors on personal research topics were…

  10. The topography of the environment alters the optimal search strategy for active particles

    Science.gov (United States)

    Volpe, Giorgio; Volpe, Giovanni

    2017-10-01

    In environments with scarce resources, adopting the right search strategy can make the difference between succeeding and failing, even between life and death. At different scales, this applies to molecular encounters in the cell cytoplasm, to animals looking for food or mates in natural landscapes, to rescuers during search and rescue operations in disaster zones, and to genetic computer algorithms exploring parameter spaces. When looking for sparse targets in a homogeneous environment, a combination of ballistic and diffusive steps is considered optimal; in particular, more ballistic Lévy flights with exponent α≤1 are generally believed to optimize the search process. However, most search spaces present complex topographies. What is the best search strategy in these more realistic scenarios? Here, we show that the topography of the environment significantly alters the optimal search strategy toward less ballistic and more Brownian strategies. We consider an active particle performing a blind cruise search for nonregenerating sparse targets in a 2D space with steps drawn from a Lévy distribution with the exponent varying from α=1 to α=2 (Brownian). We show that, when boundaries, barriers, and obstacles are present, the optimal search strategy depends on the topography of the environment, with α assuming intermediate values in the whole range under consideration. We interpret these findings using simple scaling arguments and discuss their robustness to varying searcher's size. Our results are relevant for search problems at different length scales from animal and human foraging to microswimmers' taxis to biochemical rates of reaction.

  11. Astrophysical search strategies for accelerator blind dark matter

    International Nuclear Information System (INIS)

    Wells, J.D.

    1998-04-01

    A weakly interacting dark matter particle may be very difficult to discover at an accelerator because it either (1) is too heavy, (2) has no standard model gauge interactions, or (3) is almost degenerate with other states. In each of these cases, searches for annihilation products in the galactic halo are useful probes of dark matter properties. Using the example of supersymmetric dark matter, the author demonstrates how astrophysical searches for dark matter may provide discovery and mass information inaccessible to collider physics programs such as the Tevatron and LHC

  12. Experimental implementation of a quantum random-walk search algorithm using strongly dipolar coupled spins

    International Nuclear Information System (INIS)

    Lu Dawei; Peng Xinhua; Du Jiangfeng; Zhu Jing; Zou Ping; Yu Yihua; Zhang Shanmin; Chen Qun

    2010-01-01

    An important quantum search algorithm based on the quantum random walk performs an oracle search on a database of N items with O(√(phN)) calls, yielding a speedup similar to the Grover quantum search algorithm. The algorithm was implemented on a quantum information processor of three-qubit liquid-crystal nuclear magnetic resonance (NMR) in the case of finding 1 out of 4, and the diagonal elements' tomography of all the final density matrices was completed with comprehensible one-dimensional NMR spectra. The experimental results agree well with the theoretical predictions.

  13. Win-Win transport strategies: searching for synergies.

    OpenAIRE

    Valdés Serrano, Cristina; Monzón de Cáceres, Andrés; García Benítez, Francisco

    2014-01-01

    The need of an urban transport strategy on urban areas which solves the environmental problems derived from traffic without decreasing the trip attraction of these urban areas is taken for granted. Besides there is also a clear consensus among researchers and institutions in the need for integrated transport strategies (May et al., 2006; Zhang et al., 2006). But there is still a lack of knowledge on the policy measures to be implemented. This research aims to deepen in the understanding of h...

  14. Knowledge in Artificial Intelligence Systems: Searching the Strategies for Application

    OpenAIRE

    Kornienko, Alla A.; Kornienko, Anatoly V.; Fofanov, Oleg B.; Chubik, Maxim P.

    2015-01-01

    The studies based on auto-epistemic logic are pointed out as an advanced direction for development of artificial intelligence (AI). Artificial intelligence is taken as a system that imitates the solution of complicated problems by human during the course of life. The structure of symbols and operations, by which intellectual solution is performed, as well as searching the strategic reference points for those solutions, which are caused by certain structures of symbols and operations, – are co...

  15. Strategies for the search of life in the universe

    OpenAIRE

    Schneider, Jean

    1996-01-01

    The discovery of an increasing number of Jupiter-like planets in orbit around other stars (or extra-solar planets) is a promising first step toward the search for Life in the Universe. We review all aspects of the question: - definition of Life - definition and characterization of the `habitable zone' around a star - overview of detection methods of planets, with special attention to habitable planets - present fingings - future projects.

  16. Expert Search Strategies: The Information Retrieval Practices of Healthcare Information Professionals

    OpenAIRE

    Russell-Rose, Tony; Chamberlain, Jon

    2017-01-01

    Background Healthcare information professionals play a key role in closing the knowledge gap between medical research and clinical practice. Their work involves meticulous searching of literature databases using complex search strategies that can consist of hundreds of keywords, operators, and ontology terms. This process is prone to error and can lead to inefficiency and bias if performed incorrectly. Objective The aim of this study was to investigate the search behavior of healthcare inform...

  17. Optimizing Linear Functions with Randomized Search Heuristics - The Robustness of Mutation

    DEFF Research Database (Denmark)

    Witt, Carsten

    2012-01-01

    The analysis of randomized search heuristics on classes of functions is fundamental for the understanding of the underlying stochastic process and the development of suitable proof techniques. Recently, remarkable progress has been made in bounding the expected optimization time of the simple (1...

  18. Fitness levels with tail bounds for the analysis of randomized search heuristics

    DEFF Research Database (Denmark)

    Witt, Carsten

    2014-01-01

    The fitness-level method, also called the method of f-based partitions, is an intuitive and widely used technique for the running time analysis of randomized search heuristics. It was originally defined to prove upper and lower bounds on the expected running time. Recently, upper tail bounds were...

  19. Talk as a Metacognitive Strategy during the Information Search Process of Adolescents

    Science.gov (United States)

    Bowler, Leanne

    2010-01-01

    Introduction: This paper describes a metacognitive strategy related to the social dimension of the information search process of adolescents. Method: A case study that used naturalistic methods to explore the metacognitive thinking nd associated emotions of ten adolescents. The study was framed by Kuhlthau's Information Search Process model and…

  20. A rational analysis of alternating search and reflection strategies in problem solving

    NARCIS (Netherlands)

    Taatgen, N; Shafto, MG; Langley, P

    1997-01-01

    In this paper two approaches to problem solving, search and reflection, are discussed, and combined in two models, both based on rational analysis (Anderson, 1990). The first model is a dynamic growth model, which shows that alternating search and reflection is a rational strategy. The second model

  1. Alumni Job Search Strategies, Class of 2011. GMAC[R] Data-to-Go Series

    Science.gov (United States)

    Graduate Management Admission Council, 2012

    2012-01-01

    Examining the job search strategies and employment outcomes for Class of 2011 graduate business school alumni sheds light on current job market trends and the effort required to secure a first job after earning a graduate business degree. This fact sheet highlights the job search methods used by Class of 2011 business school graduates as reported…

  2. Websites for children: search strategies and interface design. Three studies on children's search performance and evaluation

    NARCIS (Netherlands)

    Jochmann-Mannak, Hanna

    2014-01-01

    Children experience all kinds of problems using search interfaces for adults such as Google. The research reported in this dissertation is about the design of informational interfaces for children between 8 and 12 years old. The goal of the research was to learn more about interfaces that ‘work’ for

  3. How Interface Design and Search Strategy Influence Children’s Search Performance and Evaluation

    NARCIS (Netherlands)

    Jochmann-Mannak, Hanna; Lentz, Leo; Huibers, Theo W.C.; Sanders, Ted

    This chapter presents an experiment with 158 children, aged 10 to 12, in which search performance and attitudes towards an informational Website are investigated. The same Website was designed in 3 different types of interface design varying in playfulness of navigation structure and in playfulness

  4. An optimal inspection strategy for randomly failing equipment

    International Nuclear Information System (INIS)

    Chelbi, Anis; Ait-Kadi, Daoud

    1999-01-01

    This paper addresses the problem of generating optimal inspection strategies for randomly failing equipment where imminent failure is not obvious and can only be detected through inspection. Inspections are carried out following a condition-based procedure. The equipment is replaced if it has failed or if it shows imminent signs of failure. The latter state is indicated by measuring certain predetermined control parameters during inspection. Costs are associated with inspection, idle time and preventive or corrective actions. An optimal inspection strategy is defined as the inspection sequence minimizing the expected total cost per time unit over an infinite span. A mathematical model and a numerical algorithm are developed to generate an optimal inspection sequence. As a practical example, the model is applied to provide a machine tool operator with a time sequence for inspecting the cutting tool. The tool life time distribution and the trend of one control parameter defining its actual condition are supposed to be known

  5. Epidemic spreading on random surfer networks with infected avoidance strategy

    Science.gov (United States)

    Feng, Yun; Ding, Li; Huang, Yun-Han; Guan, Zhi-Hong

    2016-12-01

    In this paper, we study epidemic spreading on random surfer networks with infected avoidance (IA) strategy. In particular, we consider that susceptible individuals’ moving direction angles are affected by the current location information received from infected individuals through a directed information network. The model is mainly analyzed by discrete-time numerical simulations. The results indicate that the IA strategy can restrain epidemic spreading effectively. However, when long-distance jumps of individuals exist, the IA strategy’s effectiveness on restraining epidemic spreading is heavily reduced. Finally, it is found that the influence of the noises from information transferring process on epidemic spreading is indistinctive. Project supported in part by the National Natural Science Foundation of China (Grant Nos. 61403284, 61272114, 61673303, and 61672112) and the Marine Renewable Energy Special Fund Project of the State Oceanic Administration of China (Grant No. GHME2013JS01).

  6. A solution to energy and environmental problems of electric power system using hybrid harmony search-random search optimization algorithm

    Directory of Open Access Journals (Sweden)

    Vikram Kumar Kamboj

    2016-04-01

    Full Text Available In recent years, global warming and carbon dioxide (CO2 emission reduction have become important issues in India, as CO2 emission levels are continuing to rise in accordance with the increased volume of Indian national energy consumption under the pressure of global warming, it is crucial for Indian government to impose the effective policy to promote CO2 emission reduction. Challenge of supplying the nation with high quality and reliable electrical energy at a reasonable cost, converted government policy into deregulation and restructuring environment. This research paper presents aims to presents an effective solution for energy and environmental problems of electric power using an efficient and powerful hybrid optimization algorithm: Hybrid Harmony search-random search algorithm. The proposed algorithm is tested for standard IEEE-14 bus, -30 bus and -56 bus system. The effectiveness of proposed hybrid algorithm is compared with others well known evolutionary, heuristics and meta-heuristics search algorithms. For multi-objective unit commitment, it is found that as there are conflicting relationship between cost and emission, if the performance in cost criterion is improved, performance in the emission is seen to deteriorate.

  7. Search strategy for theorem proving in artificial systems. I

    Energy Technology Data Exchange (ETDEWEB)

    Lovitskii, V A; Barenboim, M S

    1981-01-01

    A strategy is contrived, employing the language of finite-order predicate calculus, for finding proofs of theorems. A theorem is formulated, based on 2 known theorems on purity and absorption, and used to determine 5 properties of a set of propositions. 3 references.

  8. Users’ Perceived Difficulties and Corresponding Reformulation Strategies in Google Voice Search

    Directory of Open Access Journals (Sweden)

    Wei Jeng

    2016-06-01

    Full Text Available In this article, we report users’ perceptions of query input errors and query reformulation strategies in voice search using data collected through a laboratory user study. Our results reveal that: 1 users’ perceived obstacles during a voice search can be related to speech recognition errors and topic complexity; 2 users naturally develop different strategies to deal with various types of words (e.g., acronyms, single-worded queries, non-English words with high error rates in speech recognition; and 3 users can have various emotional reactions when encounter voice input errors and they develop preferred usage occasions for voice search.

  9. Win the game of Googleopoly unlocking the secret strategy of search engines

    CERN Document Server

    Bradley, Sean V

    2015-01-01

    Rank higher in search results with this guide to SEO and content building supremacy Google is not only the number one search engine in the world, it is also the number one website in the world. Only 5 percent of site visitors search past the first page of Google, so if you're not in those top ten results, you are essentially invisible. Winning the Game of Googleopoly is the ultimate roadmap to Page One Domination. The POD strategy is what gets you on that super-critical first page of Google results by increasing your page views. You'll learn how to shape your online presence for Search Engine

  10. An automated supernova search and the design strategy

    International Nuclear Information System (INIS)

    Colgate, S.A.

    1987-01-01

    The design considerations for an automated supernova search are reviewed. If supernova are to be found a week after explosion well before light maximum of both Types I and II, and if a rate of finding of 52 per year is justified, then one needs to keep roughly 5000 galaxies under surveillance out of a full set of 15,000 galaxies at ≅50 Mpc distance. For detection at 1% of Type I maximum light requires a 30-inch telescope, 10 photoelectrons per pixel threshold, a 128 x 128 pixel photodetector operating with a 3-second integration time, and 2 seconds to slew and settle ≅1 0 . A system designed to perform this function in real-time is described. 7 refs

  11. Critical Assessment of Search Strategies in Systematic Reviews in Endodontics.

    Science.gov (United States)

    Yaylali, Ibrahim Ethem; Alaçam, Tayfun

    2016-06-01

    The aim of this study was to perform an overview of literature search strategies in systematic reviews (SRs) published in 2 endodontic journals, Journal of Endodontics and International Endodontic Journal. A search was done by using the MEDLINE (PubMed interface) database to retrieve the articles published between January 1, 2000 and December 31, 2015. The last search was on January 10, 2016. All the SRs published in the 2 journals were retrieved and screened. Eligible SRs were assessed by using 11 questions about search strategies in the SRs that were adapted from 2 guidelines (ie, AMSTAR checklist and the Cochrane Handbook). A total of 83 SRs were retrieved by electronic search. Of these, 55 were from the Journal of Endodontics, and 28 were from the International Endodontic Journal. After screening, 2 SRs were excluded, and 81 SRs were included in the study. Some issues, such as search of grey literature and contact with study authors, were not fully reported (30% and 25%, respectively). On the other hand, some issues, such as the use of index terms and key words and search in at least 2 databases, were reported in most of the SRs (97% and 95%, respectively). The overall quality of the search strategy in both journals was 61%. No significant difference was found between the 2 journals in terms of evaluation criteria (P > .05). There exist areas for improving the quality of reporting of search strategies in SRs; for example, grey literature should be searched for unpublished studies, no language limitation should be applied to databases, and authors should make an attempt to contact the authors of included studies to obtain further relevant information. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  12. Comparison of search strategies in systematic reviews of adverse effects to other systematic reviews.

    Science.gov (United States)

    Golder, Su; Loke, Yoon K; Zorzela, Liliane

    2014-06-01

    Research indicates that the methods used to identify data for systematic reviews of adverse effects may need to differ from other systematic reviews. To compare search methods in systematic reviews of adverse effects with other reviews. The search methodologies in 849 systematic reviews of adverse effects were compared with other reviews. Poor reporting of search strategies is apparent in both systematic reviews of adverse effects and other types of systematic reviews. Systematic reviews of adverse effects are less likely to restrict their searches to MEDLINE or include only randomised controlled trials (RCTs). The use of other databases is largely dependent on the topic area and the year the review was conducted, with more databases searched in more recent reviews. Adverse effects search terms are used by 72% of reviews and despite recommendations only two reviews report using floating subheadings. The poor reporting of search strategies in systematic reviews is universal, as is the dominance of searching MEDLINE. However, reviews of adverse effects are more likely to include a range of study designs (not just RCTs) and search beyond MEDLINE. © 2014 Crown Copyright.

  13. Development and use of a content search strategy for retrieving studies on patients' views and preferences.

    Science.gov (United States)

    Selva, Anna; Solà, Ivan; Zhang, Yuan; Pardo-Hernandez, Hector; Haynes, R Brian; Martínez García, Laura; Navarro, Tamara; Schünemann, Holger; Alonso-Coello, Pablo

    2017-08-30

    Identifying scientific literature addressing patients' views and preferences is complex due to the wide range of studies that can be informative and the poor indexing of this evidence. Given the lack of guidance we developed a search strategy to retrieve this type of evidence. We assembled an initial list of terms from several sources, including the revision of the terms and indexing of topic-related studies and, methods research literature, and other relevant projects and systematic reviews. We used the relative recall approach, evaluating the capacity of the designed search strategy for retrieving studies included in relevant systematic reviews for the topic. We implemented in practice the final version of the search strategy for conducting systematic reviews and guidelines, and calculated search's precision and the number of references needed to read (NNR). We assembled an initial version of the search strategy, which had a relative recall of 87.4% (yield of 132/out of 151 studies). We then added some additional terms from the studies not initially identified, and re-tested this improved version against the studies included in a new set of systematic reviews, reaching a relative recall of 85.8% (151/out of 176 studies, 95% CI 79.9 to 90.2). This final version of the strategy includes two sets of terms related with two domains: "Patient Preferences and Decision Making" and "Health State Utilities Values". When we used the search strategy for the development of systematic reviews and clinical guidelines we obtained low precision values (ranging from 2% to 5%), and the NNR from 20 to 50. This search strategy fills an important research gap in this field. It will help systematic reviewers, clinical guideline developers, and policy-makers to retrieve published research on patients' views and preferences. In turn, this will facilitate the inclusion of this critical aspect when formulating heath care decisions, including recommendations.

  14. Searches for Randomized Controlled Trials of Drugs in MEDLINE and EMBASE Using Only Generic Drug Names Compared with Searches Applied in Current Practice in Systematic Reviews

    Science.gov (United States)

    Waffenschmidt, Siw; Guddat, Charlotte

    2015-01-01

    Background: It is unclear which terms should be included in bibliographic searches for randomized controlled trials (RCTs) of drugs, and identifying relevant drug terms can be extremely laborious. The aim of our analysis was to determine whether a bibliographic search using only the generic drug name produces sufficient results for the generation…

  15. Searching for Survivors through Random Human-Body Movement Outdoors by Continuous-Wave Radar Array.

    Science.gov (United States)

    Li, Chuantao; Chen, Fuming; Qi, Fugui; Liu, Miao; Li, Zhao; Liang, Fulai; Jing, Xijing; Lu, Guohua; Wang, Jianqi

    2016-01-01

    It is a major challenge to search for survivors after chemical or nuclear leakage or explosions. At present, biological radar can be used to achieve this goal by detecting the survivor's respiration signal. However, owing to the random posture of an injured person at a rescue site, the radar wave may directly irradiate the person's head or feet, in which it is difficult to detect the respiration signal. This paper describes a multichannel-based antenna array technology, which forms an omnidirectional detection system via 24-GHz Doppler biological radar, to address the random positioning relative to the antenna of an object to be detected. Furthermore, since the survivors often have random body movement such as struggling and twitching, the slight movements of the body caused by breathing are obscured by these movements. Therefore, a method is proposed to identify random human-body movement by utilizing multichannel information to calculate the background variance of the environment in combination with a constant-false-alarm-rate detector. The conducted outdoor experiments indicate that the system can realize the omnidirectional detection of random human-body movement and distinguish body movement from environmental interference such as movement of leaves and grass. The methods proposed in this paper will be a promising way to search for survivors outdoors.

  16. Searching for Survivors through Random Human-Body Movement Outdoors by Continuous-Wave Radar Array

    Science.gov (United States)

    Liu, Miao; Li, Zhao; Liang, Fulai; Jing, Xijing; Lu, Guohua; Wang, Jianqi

    2016-01-01

    It is a major challenge to search for survivors after chemical or nuclear leakage or explosions. At present, biological radar can be used to achieve this goal by detecting the survivor’s respiration signal. However, owing to the random posture of an injured person at a rescue site, the radar wave may directly irradiate the person’s head or feet, in which it is difficult to detect the respiration signal. This paper describes a multichannel-based antenna array technology, which forms an omnidirectional detection system via 24-GHz Doppler biological radar, to address the random positioning relative to the antenna of an object to be detected. Furthermore, since the survivors often have random body movement such as struggling and twitching, the slight movements of the body caused by breathing are obscured by these movements. Therefore, a method is proposed to identify random human-body movement by utilizing multichannel information to calculate the background variance of the environment in combination with a constant-false-alarm-rate detector. The conducted outdoor experiments indicate that the system can realize the omnidirectional detection of random human-body movement and distinguish body movement from environmental interference such as movement of leaves and grass. The methods proposed in this paper will be a promising way to search for survivors outdoors. PMID:27073860

  17. Inference-Based Similarity Search in Randomized Montgomery Domains for Privacy-Preserving Biometric Identification.

    Science.gov (United States)

    Wang, Yi; Wan, Jianwu; Guo, Jun; Cheung, Yiu-Ming; C Yuen, Pong

    2017-07-14

    Similarity search is essential to many important applications and often involves searching at scale on high-dimensional data based on their similarity to a query. In biometric applications, recent vulnerability studies have shown that adversarial machine learning can compromise biometric recognition systems by exploiting the biometric similarity information. Existing methods for biometric privacy protection are in general based on pairwise matching of secured biometric templates and have inherent limitations in search efficiency and scalability. In this paper, we propose an inference-based framework for privacy-preserving similarity search in Hamming space. Our approach builds on an obfuscated distance measure that can conceal Hamming distance in a dynamic interval. Such a mechanism enables us to systematically design statistically reliable methods for retrieving most likely candidates without knowing the exact distance values. We further propose to apply Montgomery multiplication for generating search indexes that can withstand adversarial similarity analysis, and show that information leakage in randomized Montgomery domains can be made negligibly small. Our experiments on public biometric datasets demonstrate that the inference-based approach can achieve a search accuracy close to the best performance possible with secure computation methods, but the associated cost is reduced by orders of magnitude compared to cryptographic primitives.

  18. Effects of systematic phase errors on optimized quantum random-walk search algorithm

    International Nuclear Information System (INIS)

    Zhang Yu-Chao; Bao Wan-Su; Wang Xiang; Fu Xiang-Qun

    2015-01-01

    This study investigates the effects of systematic errors in phase inversions on the success rate and number of iterations in the optimized quantum random-walk search algorithm. Using the geometric description of this algorithm, a model of the algorithm with phase errors is established, and the relationship between the success rate of the algorithm, the database size, the number of iterations, and the phase error is determined. For a given database size, we obtain both the maximum success rate of the algorithm and the required number of iterations when phase errors are present in the algorithm. Analyses and numerical simulations show that the optimized quantum random-walk search algorithm is more robust against phase errors than Grover’s algorithm. (paper)

  19. Biclustering of gene expression data using reactive greedy randomized adaptive search procedure.

    Science.gov (United States)

    Dharan, Smitha; Nair, Achuthsankar S

    2009-01-30

    Biclustering algorithms belong to a distinct class of clustering algorithms that perform simultaneous clustering of both rows and columns of the gene expression matrix and can be a very useful analysis tool when some genes have multiple functions and experimental conditions are diverse. Cheng and Church have introduced a measure called mean squared residue score to evaluate the quality of a bicluster and has become one of the most popular measures to search for biclusters. In this paper, we review basic concepts of the metaheuristics Greedy Randomized Adaptive Search Procedure (GRASP)-construction and local search phases and propose a new method which is a variant of GRASP called Reactive Greedy Randomized Adaptive Search Procedure (Reactive GRASP) to detect significant biclusters from large microarray datasets. The method has two major steps. First, high quality bicluster seeds are generated by means of k-means clustering. In the second step, these seeds are grown using the Reactive GRASP, in which the basic parameter that defines the restrictiveness of the candidate list is self-adjusted, depending on the quality of the solutions found previously. We performed statistical and biological validations of the biclusters obtained and evaluated the method against the results of basic GRASP and as well as with the classic work of Cheng and Church. The experimental results indicate that the Reactive GRASP approach outperforms the basic GRASP algorithm and Cheng and Church approach. The Reactive GRASP approach for the detection of significant biclusters is robust and does not require calibration efforts.

  20. Search strategy has influenced the discovery rate of human viruses.

    Science.gov (United States)

    Rosenberg, Ronald; Johansson, Michael A; Powers, Ann M; Miller, Barry R

    2013-08-20

    A widely held concern is that the pace of infectious disease emergence has been increasing. We have analyzed the rate of discovery of pathogenic viruses, the preeminent source of newly discovered causes of human disease, from 1897 through 2010. The rate was highest during 1950-1969, after which it moderated. This general picture masks two distinct trends: for arthropod-borne viruses, which comprised 39% of pathogenic viruses, the discovery rate peaked at three per year during 1960-1969, but subsequently fell nearly to zero by 1980; however, the rate of discovery of nonarboviruses remained stable at about two per year from 1950 through 2010. The period of highest arbovirus discovery coincided with a comprehensive program supported by The Rockefeller Foundation of isolating viruses from humans, animals, and arthropod vectors at field stations in Latin America, Africa, and India. The productivity of this strategy illustrates the importance of location, approach, long-term commitment, and sponsorship in the discovery of emerging pathogens.

  1. Research on the optimization strategy of web search engine based on data mining

    Science.gov (United States)

    Chen, Ronghua

    2018-04-01

    With the wide application of search engines, web site information has become an important way for people to obtain information. People have found that they are growing in an increasingly explosive manner. Web site information is verydifficult to find the information they need, and now the search engine can not meet the need, so there is an urgent need for the network to provide website personalized information service, data mining technology for this new challenge is to find a breakthrough. In order to improve people's accuracy of finding information from websites, a website search engine optimization strategy based on data mining is proposed, and verified by website search engine optimization experiment. The results show that the proposed strategy improves the accuracy of the people to find information, and reduces the time for people to find information. It has an important practical value.

  2. PARAMETRIC IDENTIFICATION OF STOCHASTIC SYSTEM BY NON-GRADIENT RANDOM SEARCHING

    Directory of Open Access Journals (Sweden)

    A. A. Lobaty

    2017-01-01

    Full Text Available At this moment we know a great variety of identification objects, tasks and methods and its significance is constantly increasing in various fields of science and technology.  The identification problem is dependent on a priori information about identification object, besides that  the existing approaches and methods of identification are determined by the form of mathematical models (deterministic, stochastic, frequency, temporal, spectral etc.. The paper considers a problem for determination of system parameters  (identification object which is assigned by the stochastic mathematical model including random functions of time. It has been shown  that while making optimization of the stochastic systems subject to random actions deterministic methods can be applied only for a limited approximate optimization of the system by taking into account average random effects and fixed structure of the system. The paper proposes an algorithm for identification of  parameters in a mathematical model of  the stochastic system by non-gradient random searching. A specific  feature  of the algorithm is its applicability  practically to mathematic models of any type because the applied algorithm does not depend on linearization and differentiability of functions included in the mathematical model of the system. The proposed algorithm  ensures searching of  an extremum for the specified quality criteria in terms of external uncertainties and limitations while using random searching of parameters for a mathematical model of the system. The paper presents results of the investigations on operational capability of the considered identification method  while using mathematical simulation of hypothetical control system with a priori unknown parameter values of the mathematical model. The presented results of the mathematical simulation obviously demonstrate the operational capability of the proposed identification method.

  3. A comparison of information functions and search strategies for sensor planning in target classification.

    Science.gov (United States)

    Zhang, Guoxian; Ferrari, Silvia; Cai, Chenghui

    2012-02-01

    This paper investigates the comparative performance of several information-driven search strategies and decision rules using a canonical target classification problem. Five sensor models are considered: one obtained from classical estimation theory and four obtained from Bernoulli, Poisson, binomial, and mixture-of-binomial distributions. A systematic approach is presented for deriving information functions that represent the expected utility of future sensor measurements from mutual information, Rènyi divergence, Kullback-Leibler divergence, information potential, quadratic entropy, and the Cauchy-Schwarz distance. The resulting information-driven strategies are compared to direct-search, alert-confirm, task-driven (TS), and log-likelihood-ratio (LLR) search strategies. Extensive numerical simulations show that quadratic entropy typically leads to the most effective search strategy with respect to correct-classification rates. In the presence of prior information, the quadratic-entropy-driven strategy also displays the lowest rate of false alarms. However, when prior information is absent or very noisy, TS and LLR strategies achieve the lowest false-alarm rates for the Bernoulli, mixture-of-binomial, and classical sensor models.

  4. Sleuth: A quasi-model-independent search strategy for new physics

    International Nuclear Information System (INIS)

    Bruce O. Knuteson

    2001-01-01

    How can we search for new physics when we only vaguely know what it should look like? How can we perform an unbiased yet data-driven search? If we see apparently anomalous events in our data, how can we quantify their ''interestingness'' a posteriori? We present an analysis strategy (SLEUTH) that simultaneously addresses each of these questions, and we demonstrate its application to over thirty exclusive final states in data collected by D0 in Run I of the Fermilab Tevatron

  5. Optimal Search Strategy of Robotic Assembly Based on Neural Vibration Learning

    Directory of Open Access Journals (Sweden)

    Lejla Banjanovic-Mehmedovic

    2011-01-01

    Full Text Available This paper presents implementation of optimal search strategy (OSS in verification of assembly process based on neural vibration learning. The application problem is the complex robot assembly of miniature parts in the example of mating the gears of one multistage planetary speed reducer. Assembly of tube over the planetary gears was noticed as the most difficult problem of overall assembly. The favourable influence of vibration and rotation movement on compensation of tolerance was also observed. With the proposed neural-network-based learning algorithm, it is possible to find extended scope of vibration state parameter. Using optimal search strategy based on minimal distance path between vibration parameter stage sets (amplitude and frequencies of robots gripe vibration and recovery parameter algorithm, we can improve the robot assembly behaviour, that is, allow the fastest possible way of mating. We have verified by using simulation programs that search strategy is suitable for the situation of unexpected events due to uncertainties.

  6. A Semidefinite Programming Based Search Strategy for Feature Selection with Mutual Information Measure.

    Science.gov (United States)

    Naghibi, Tofigh; Hoffmann, Sarah; Pfister, Beat

    2015-08-01

    Feature subset selection, as a special case of the general subset selection problem, has been the topic of a considerable number of studies due to the growing importance of data-mining applications. In the feature subset selection problem there are two main issues that need to be addressed: (i) Finding an appropriate measure function than can be fairly fast and robustly computed for high-dimensional data. (ii) A search strategy to optimize the measure over the subset space in a reasonable amount of time. In this article mutual information between features and class labels is considered to be the measure function. Two series expansions for mutual information are proposed, and it is shown that most heuristic criteria suggested in the literature are truncated approximations of these expansions. It is well-known that searching the whole subset space is an NP-hard problem. Here, instead of the conventional sequential search algorithms, we suggest a parallel search strategy based on semidefinite programming (SDP) that can search through the subset space in polynomial time. By exploiting the similarities between the proposed algorithm and an instance of the maximum-cut problem in graph theory, the approximation ratio of this algorithm is derived and is compared with the approximation ratio of the backward elimination method. The experiments show that it can be misleading to judge the quality of a measure solely based on the classification accuracy, without taking the effect of the non-optimum search strategy into account.

  7. A random-key encoded harmony search approach for energy-efficient production scheduling with shared resources

    Science.gov (United States)

    Garcia-Santiago, C. A.; Del Ser, J.; Upton, C.; Quilligan, F.; Gil-Lopez, S.; Salcedo-Sanz, S.

    2015-11-01

    When seeking near-optimal solutions for complex scheduling problems, meta-heuristics demonstrate good performance with affordable computational effort. This has resulted in a gravitation towards these approaches when researching industrial use-cases such as energy-efficient production planning. However, much of the previous research makes assumptions about softer constraints that affect planning strategies and about how human planners interact with the algorithm in a live production environment. This article describes a job-shop problem that focuses on minimizing energy consumption across a production facility of shared resources. The application scenario is based on real facilities made available by the Irish Center for Manufacturing Research. The formulated problem is tackled via harmony search heuristics with random keys encoding. Simulation results are compared to a genetic algorithm, a simulated annealing approach and a first-come-first-served scheduling. The superior performance obtained by the proposed scheduler paves the way towards its practical implementation over industrial production chains.

  8. The search for dark matter in xenon: Innovative calibration strategies and novel search channels

    Science.gov (United States)

    Reichard, Shayne Edward

    The direct detection dark matter experiment XENON1T became operational in early 2016, heralding the era of tonne-scale dark matter detectors. Direct detection experiments typically search for elastic scatters of dark matter particles off target nuclei. XENON1T's larger xenon target provides the advantage of stronger dark matter signals and lower background rates compared to its predecessors, XENON10 and XENON100; but, at the same time, calibration of the detector's response to backgrounds with traditional external sources becomes exceedingly more difficult. A 220Rn source is deployed on the XENON100 dark matter detector in order to address the challenges in calibration of tonne-scale liquid noble element detectors. I show that the subsequent 212Pb beta emission can be used for low-energy electronic recoil calibration in searches for dark matter. The isotope spreads throughout the entire active region of the detector, and its activity naturally decays below background level within a week after the source is closed. I find no increase in the activity of the troublesome 222Rn background after calibration. Alpha emitters are also distributed throughout the detector and facilitate calibration of its response to 222Rn. Using the delayed coincidence of 220Rn/216Po, I map for the first time the convective motion of particles in the XENON100 detector. Additionally, I make a competitive measurement of the half-life of 212Po, t1/2=293.9+/-(1.0)stat+/-(0.6)ns. In contrast to the elastic scattering of dark matter particles off nuclei, I explore inelastic scattering where the nucleus is excited to a low-lying state of 10-100 keV, with a subsequent prompt de-excitation. I use the inelastic structure factors for the odd-mass xenon isotopes based on state-of-the-art large-scale shell-model calculations with chiral effective field theory WIMP-nucleon currents, finding that the inelastic channel is comparable to or can dominate the elastic channel for momentum transfers around 150 Me

  9. Developing optimal search strategies for detecting clinically sound prognostic studies in MEDLINE: an analytic survey

    Directory of Open Access Journals (Sweden)

    Haynes R Brian

    2004-06-01

    Full Text Available Abstract Background Clinical end users of MEDLINE have a difficult time retrieving articles that are both scientifically sound and directly relevant to clinical practice. Search filters have been developed to assist end users in increasing the success of their searches. Many filters have been developed for the literature on therapy and reviews but little has been done in the area of prognosis. The objective of this study is to determine how well various methodologic textwords, Medical Subject Headings, and their Boolean combinations retrieve methodologically sound literature on the prognosis of health disorders in MEDLINE. Methods An analytic survey was conducted, comparing hand searches of journals with retrievals from MEDLINE for candidate search terms and combinations. Six research assistants read all issues of 161 journals for the publishing year 2000. All articles were rated using purpose and quality indicators and categorized into clinically relevant original studies, review articles, general papers, or case reports. The original and review articles were then categorized as 'pass' or 'fail' for methodologic rigor in the areas of prognosis and other clinical topics. Candidate search strategies were developed for prognosis and run in MEDLINE – the retrievals being compared with the hand search data. The sensitivity, specificity, precision, and accuracy of the search strategies were calculated. Results 12% of studies classified as prognosis met basic criteria for scientific merit for testing clinical applications. Combinations of terms reached peak sensitivities of 90%. Compared with the best single term, multiple terms increased sensitivity for sound studies by 25.2% (absolute increase, and increased specificity, but by a much smaller amount (1.1% when sensitivity was maximized. Combining terms to optimize both sensitivity and specificity achieved sensitivities and specificities of approximately 83% for each. Conclusion Empirically derived

  10. Wayfinding search strategies and matching familiarity in the built environment through virtual navigation

    NARCIS (Netherlands)

    Dijkstra, J.; Vries, de B.; Jessurun, A.J.

    2014-01-01

    There is an underestimation of the conscious and unconscious wayfinding search strategies in a virtual built environment without signage information. Wayfinding is the process of determining and following a path or route between an origin and destination.This is the base of the experiment discussed

  11. Design and Implementation of Cancellation Tasks for Visual Search Strategies and Visual Attention in School Children

    Science.gov (United States)

    Wang, Tsui-Ying; Huang, Ho-Chuan; Huang, Hsiu-Shuang

    2006-01-01

    We propose a computer-assisted cancellation test system (CACTS) to understand the visual attention performance and visual search strategies in school children. The main aim of this paper is to present our design and development of the CACTS and demonstrate some ways in which computer techniques can allow the educator not only to obtain more…

  12. WANDERER IN THE MIST: THE SEARCH FOR INTELLIGENCE, SURVEILLANCE, AND RECONNAISSANCE (ISR) STRATEGY

    Science.gov (United States)

    2017-06-01

    the production of over 383,000 photographic prints to support various intelligence , mapping, and 15...WANDERER IN THE MIST: THE SEARCH FOR INTELLIGENCE , SURVEILLANCE, AND RECONNAISSANCE (ISR) STRATEGY BY MAJOR RYAN D. SKAGGS, USAF...program from the University of California at Los Angeles (UCLA) in 2004. He is a career intelligence officer with over 13 years of experience across a

  13. The “I’m Feeling Lucky Syndrome”: Teacher-Candidates’ Knowledge of Web Searching Strategies

    Directory of Open Access Journals (Sweden)

    Corinne Laverty

    2008-06-01

    Full Text Available The need for web literacy has become increasingly important with the exponential growth of learning materials on the web that are freely accessible to educators. Teachers need the skills to locate these tools and also the ability to teach their students web search strategies and evaluation of websites so they can effectively explore the web by themselves. This study examined the web searching strategies of 253 teachers-in-training using both a survey (247 participants and live screen capture with think aloud audio recording (6 participants. The results present a picture of the strategic, syntactic, and evaluative search abilities of these students that librarians and faculty can use to plan how instruction can target information skill deficits in university student populations.

  14. Institutional Embeddedness of Search Strategies and the Implications for Innovation Performance

    DEFF Research Database (Denmark)

    Grimpe, Christoph; Sofka, Wolfgang

    2013-01-01

    to experience the negative performance effects of oversearch. Based on a comprehensive sample of almost 8,000 firms from ten European countries, we find that institutions matter considerably for firms’ search activity. Higher market orientation of institutions increases the effectiveness of firms’ search...... ignored the institutional context that provides or denies access to external knowledge at the country level. Combining institutional and knowledge search theory, we suggest that the market orientation of the institutional environment and the magnitude of institutional change influence when firms begin...... for external knowledge while higher magnitudes of institutional change decrease it. Our results provide important insights for management on how to adapt search strategies to the institutional context....

  15. A fast search strategy for gravitational waves from low-mass x-ray binaries

    International Nuclear Information System (INIS)

    Messenger, C; Woan, G

    2007-01-01

    We present a new type of search strategy designed specifically to find continuously emitting gravitational wave sources in known binary systems. A component of this strategy is based on the incoherent summation of frequency-modulated binary signal sidebands, a method previously employed in the detection of electromagnetic pulsar signals from radio observations. The search pipeline can be divided into three stages: the first is a wide bandwidth, F-statistic search demodulated for sky position. This is followed by a fast second stage in which areas in frequency space are identified as signal candidates through the frequency domain convolution of the F-statistic with an approximate signal template. For this second stage only precise information on the orbit period and approximate information on the orbital semi-major axis are required a priori. For the final stage we propose a fully coherent Markov chain Monte Carlo based follow-up search on the frequency subspace defined by the candidates identified by the second stage. This search is particularly suited to the low-mass x-ray binaries, for which orbital period and sky position are typically well known and additional orbital parameters and neutron star spin frequency are not. We note that for the accreting x-ray millisecond pulsars, for which spin frequency and orbital parameters are well known, the second stage can be omitted and the fully coherent search stage can be performed. We describe the search pipeline with respect to its application to a simplified phase model and derive the corresponding sensitivity of the search

  16. Information search and decision making: effects of age and complexity on strategy use.

    Science.gov (United States)

    Queen, Tara L; Hess, Thomas M; Ennis, Gilda E; Dowd, Keith; Grühn, Daniel

    2012-12-01

    The impact of task complexity on information search strategy and decision quality was examined in a sample of 135 young, middle-aged, and older adults. We were particularly interested in the competing roles of fluid cognitive ability and domain knowledge and experience, with the former being a negative influence and the latter being a positive influence on older adults' performance. Participants utilized 2 decision matrices, which varied in complexity, regarding a consumer purchase. Using process tracing software and an algorithm developed to assess decision strategy, we recorded search behavior, strategy selection, and final decision. Contrary to expectations, older adults were not more likely than the younger age groups to engage in information-minimizing search behaviors in response to increases in task complexity. Similarly, adults of all ages used comparable decision strategies and adapted their strategies to the demands of the task. We also examined decision outcomes in relation to participants' preferences. Overall, it seems that older adults utilize simpler sets of information primarily reflecting the most valued attributes in making their choice. The results of this study suggest that older adults are adaptive in their approach to decision making and that this ability may benefit from accrued knowledge and experience. 2013 APA, all rights reserved

  17. Identifying quality improvement intervention publications - A comparison of electronic search strategies

    Directory of Open Access Journals (Sweden)

    Rubenstein Lisa V

    2011-08-01

    Full Text Available Abstract Background The evidence base for quality improvement (QI interventions is expanding rapidly. The diversity of the initiatives and the inconsistency in labeling these as QI interventions makes it challenging for researchers, policymakers, and QI practitioners to access the literature systematically and to identify relevant publications. Methods We evaluated search strategies developed for MEDLINE (Ovid and PubMed based on free text words, Medical subject headings (MeSH, QI intervention components, continuous quality improvement (CQI methods, and combinations of the strategies. Three sets of pertinent QI intervention publications were used for validation. Two independent expert reviewers screened publications for relevance. We compared the yield, recall rate, and precision of the search strategies for the identification of QI publications and for a subset of empirical studies on effects of QI interventions. Results The search yields ranged from 2,221 to 216,167 publications. Mean recall rates for reference publications ranged from 5% to 53% for strategies with yields of 50,000 publications or fewer. The 'best case' strategy, a simple text word search with high face validity ('quality' AND 'improv*' AND 'intervention*' identified 44%, 24%, and 62% of influential intervention articles selected by Agency for Healthcare Research and Quality (AHRQ experts, a set of exemplar articles provided by members of the Standards for Quality Improvement Reporting Excellence (SQUIRE group, and a sample from the Cochrane Effective Practice and Organization of Care Group (EPOC register of studies, respectively. We applied the search strategy to a PubMed search for articles published in 10 pertinent journals in a three-year period which retrieved 183 publications. Among these, 67% were deemed relevant to QI by at least one of two independent raters. Forty percent were classified as empirical studies reporting on a QI intervention. Conclusions The presented

  18. Sensitivity and predictive value of 15 PubMed search strategies to answer clinical questions rated against full systematic reviews.

    Science.gov (United States)

    Agoritsas, Thomas; Merglen, Arnaud; Courvoisier, Delphine S; Combescure, Christophe; Garin, Nicolas; Perrier, Arnaud; Perneger, Thomas V

    2012-06-12

    Clinicians perform searches in PubMed daily, but retrieving relevant studies is challenging due to the rapid expansion of medical knowledge. Little is known about the performance of search strategies when they are applied to answer specific clinical questions. To compare the performance of 15 PubMed search strategies in retrieving relevant clinical trials on therapeutic interventions. We used Cochrane systematic reviews to identify relevant trials for 30 clinical questions. Search terms were extracted from the abstract using a predefined procedure based on the population, interventions, comparison, outcomes (PICO) framework and combined into queries. We tested 15 search strategies that varied in their query (PIC or PICO), use of PubMed's Clinical Queries therapeutic filters (broad or narrow), search limits, and PubMed links to related articles. We assessed sensitivity (recall) and positive predictive value (precision) of each strategy on the first 2 PubMed pages (40 articles) and on the complete search output. The performance of the search strategies varied widely according to the clinical question. Unfiltered searches and those using the broad filter of Clinical Queries produced large outputs and retrieved few relevant articles within the first 2 pages, resulting in a median sensitivity of only 10%-25%. In contrast, all searches using the narrow filter performed significantly better, with a median sensitivity of about 50% (all P PubMed pages. These results can help clinicians apply effective strategies to answer their questions at the point of care.

  19. Search strategy in a complex and dynamic environment (the Indian Ocean case)

    Science.gov (United States)

    Loire, Sophie; Arbabi, Hassan; Clary, Patrick; Ivic, Stefan; Crnjaric-Zic, Nelida; Macesic, Senka; Crnkovic, Bojan; Mezic, Igor; UCSB Team; Rijeka Team

    2014-11-01

    The disappearance of Malaysia Airlines Flight 370 (MH370) in the early morning hours of 8 March 2014 has exposed the disconcerting lack of efficient methods for identifying where to look and how to look for missing objects in a complex and dynamic environment. The search area for plane debris is a remote part of the Indian Ocean. Searches, of the lawnmower type, have been unsuccessful so far. Lagrangian kinematics of mesoscale features are visible in hypergraph maps of the Indian Ocean surface currents. Without a precise knowledge of the crash site, these maps give an estimate of the time evolution of any initial distribution of plane debris and permits the design of a search strategy. The Dynamic Spectral Multiscale Coverage search algorithm is modified to search a spatial distribution of targets that is evolving with time following the dynamic of ocean surface currents. Trajectories are generated for multiple search agents such that their spatial coverage converges to the target distribution. Central to this DSMC algorithm is a metric for the ergodicity.

  20. A novel ternary content addressable memory design based on resistive random access memory with high intensity and low search energy

    Science.gov (United States)

    Han, Runze; Shen, Wensheng; Huang, Peng; Zhou, Zheng; Liu, Lifeng; Liu, Xiaoyan; Kang, Jinfeng

    2018-04-01

    A novel ternary content addressable memory (TCAM) design based on resistive random access memory (RRAM) is presented. Each TCAM cell consists of two parallel RRAM to both store and search for ternary data. The cell size of the proposed design is 8F2, enable a ∼60× cell area reduction compared with the conventional static random access memory (SRAM) based implementation. Simulation results also show that the search delay and energy consumption of the proposed design at the 64-bit word search are 2 ps and 0.18 fJ/bit/search respectively at 22 nm technology node, where significant improvements are achieved compared to previous works. The desired characteristics of RRAM for implementation of the high performance TCAM search chip are also discussed.

  1. The biennial life strategy in a random environment

    NARCIS (Netherlands)

    Roerdink, J.B.T.M.

    1988-01-01

    A discrete-time population model with two age classes is studied which describes the growth of biennial plants in a randomly varying environment. A fraction of the oldest age class delays its flowering each year. The solution of the model involves products of random matrices. We calculate the exact

  2. Improving the basic skills of teaching mathematics through learning with search-solve-create-share strategy

    Science.gov (United States)

    Rahayu, D. V.; Kusumah, Y. S.; Darhim

    2018-05-01

    This study examined to see the improvement of prospective teachers’ basic skills of teaching mathematics through search-solve-create-share learning strategy based on overall and Mathematical Prior Knowledge (MPK) and interaction of both. Quasi experiments with the design of this experimental-non-equivalent control group design involved 67 students at the mathematics program of STKIP Garut. The instrument used in this study included pre-test and post-test. The result of this study showed that: (1) The improvement and achievement of the basic skills of teaching mathematics of the prospective teachers who get the learning of search-solve-create-share strategy is better than the improvement and achievement of the prospective teachers who get the conventional learning as a whole and based on MPK; (2) There is no interaction between the learning used and MPK on improving and achieving basic skills of teaching mathematics.

  3. Martian methane plume models for defining Mars rover methane source search strategies

    Science.gov (United States)

    Nicol, Christopher; Ellery, Alex; Lynch, Brian; Cloutis, Ed

    2018-07-01

    The detection of atmospheric methane on Mars implies an active methane source. This introduces the possibility of a biotic source with the implied need to determine whether the methane is indeed biotic in nature or geologically generated. There is a clear need for robotic algorithms which are capable of manoeuvring a rover through a methane plume on Mars to locate its source. We explore aspects of Mars methane plume modelling to reveal complex dynamics characterized by advection and diffusion. A statistical analysis of the plume model has been performed and compared to analyses of terrestrial plume models. Finally, we consider a robotic search strategy to find a methane plume source. We find that gradient-based techniques are ineffective, but that more sophisticated model-based search strategies are unlikely to be available in near-term rover missions.

  4. Evolution of optimal Lévy-flight strategies in human mental searches

    Science.gov (United States)

    Radicchi, Filippo; Baronchelli, Andrea

    2012-06-01

    Recent analysis of empirical data [Radicchi, Baronchelli, and Amaral, PloS ONE1932-620310.1371/journal.pone.0029910 7, e029910 (2012)] showed that humans adopt Lévy-flight strategies when exploring the bid space in online auctions. A game theoretical model proved that the observed Lévy exponents are nearly optimal, being close to the exponent value that guarantees the maximal economical return to players. Here, we rationalize these findings by adopting an evolutionary perspective. We show that a simple evolutionary process is able to account for the empirical measurements with the only assumption that the reproductive fitness of the players is proportional to their search ability. Contrary to previous modeling, our approach describes the emergence of the observed exponent without resorting to any strong assumptions on the initial searching strategies. Our results generalize earlier research, and open novel questions in cognitive, behavioral, and evolutionary sciences.

  5. Looking for trouble: a description of oculomotor search strategies during live CCTV operation.

    Science.gov (United States)

    Stainer, Matthew J; Scott-Brown, Kenneth C; Tatler, Benjamin W

    2013-01-01

    Recent research has begun to address how CCTV operators in the modern control room attempt to search for crime (e.g., Howard et al., 2011). However, an often-neglected element of the CCTV task is that the operators have at their disposal a multiplexed wall of scenes, and a single spot-monitor on which they can select any of these feeds for inspection. Here we examined how 2 trained CCTV operators used these sources of information to search from crime during a morning, afternoon, and night-time shift. We found that they spent surprisingly little time viewing the multiplex wall, instead preferentially spending most of their time searching on the single-scene spot-monitor. Such search must require a sophisticated understanding of the surveilled environment, as the operators must make their selection of which screen to view based on their prediction of where crime is likely to occur. This seems to be reflected in the difference in the screens that they selected to view at different times of the day. For example, night-clubs received close monitoring at night, but were seldom viewed in mid-morning. Such narrowing of search based on a contextual understanding of an environment is not a new idea (e.g., Torralba et al., 2006), and appears to contribute to operator's selection strategy. This research prompts new questions regarding the nature of representation that operators have of their environment, and how they might develop expectation-based search strategies to countermand the demands of the large influx of visual information. Future research should ensure not to neglect examination of operator behavior "in the wild" (Hutchins, 1995a), as such insights are difficult to gain from laboratory based paradigms alone.

  6. Looking for trouble: A description of oculomotor search strategies during live CCTV operation.

    Directory of Open Access Journals (Sweden)

    Matthew James Stainer

    2013-09-01

    Full Text Available Recent research has begun to address how CCTV operators in the modern control room attempt to search for crime (e.g., Howard et al., 2011. However, an often-neglected element of the CCTV task is that the operators have at their disposal a multiplexed wall of scenes, and a single spot-monitor on which they can select any of these feeds for inspection. Here we examined how 2 trained CCTV operators used these sources of information to search from crime during a morning, afternoon and night-time shift. We found that they spent surprisingly little time viewing the multiplex wall, instead preferentially spending most of their time searching on the single-scene spot-monitor. Such search must require a sophisticated understanding of the surveilled environment, as the operators must make their selection of which screen to view based on their prediction of where crime is likely to occur. This seems to be reflected in the difference in the screens that they selected to view at different times of the day. For example, night-clubs received close monitoring at night, but were seldom viewed in mid-morning. Such narrowing of search based on a contextual understanding of an environment is not a new idea (e.g., Torralba et al., 2006, and appears to contribute to operator’s selection strategy. This research prompts new questions regarding the nature of representation that operators have of their environment, and how they might develop expectation-based search strategies to countermand the demands of the large influx of visual information. Future research should ensure not to neglect examination of operator behavior ‘in the wild’ (Hutchins, 1995a, as such insights are difficult to gain from laboratory based paradigms alone.

  7. Search Strategies Used by Older Adults in a Virtual Reality Place Learning Task.

    Science.gov (United States)

    Davis, Rebecca L; Weisbeck, Catherine

    2015-06-01

    Older adults often have problems finding their way in novel environments such as senior living residences and hospitals. The purpose of this study was to examine the types of self-reported search strategies and cues that older adults use to find their way in a virtual maze. Healthy, independently living older adults (n = 129) aged 55-96 were tested in a virtual maze task over a period of 3 days in which they had to repeatedly find their way to a specified goal. They were interviewed about their strategies on days 1 and 3. Content analysis was used to identify the strategies and cues described by the participants in order to find their way. Strategies and cues used were compared among groups. The participants reported the use of multiple spatial and non-spatial strategies, and some of the strategies differed among age groups and over time. The oldest age group was less likely to use strategies such as triangulation and distance strategies. All participants used visual landmarks to find their way, but the use of geometric cues (corners) was used less by the older participants. These findings add to the theoretical understanding of how older adults find their way in complex environments. The understanding of how wayfinding changes with age is essential in order to design more supportive environments. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. PubMed search strategies for the identification of etiologic associations between hypothalamic-pituitary disorders and other medical conditions.

    Science.gov (United States)

    Guaraldi, Federica; Grottoli, Silvia; Arvat, Emanuela; Mattioli, Stefano; Ghigo, Ezio; Gori, Davide

    2013-12-01

    Biomedical literature has enormously grown in the last decades and become broadly available through online databases. Ad-hoc search methods, created on the basis of research field and goals, are required to enhance the quality of searching. Aim of this study was to formulate efficient, evidence-based PubMed search strategies to retrieve articles assessing etiologic associations between a condition of interest and hypothalamic-pituitary disorders (HPD). Based on expert knowledge, 17 MeSH (Medical Subjects Headings) and 79 free terms related to HPD were identified to search PubMed. Using random samples of abstracts retrieved by each term, we estimated the proportion of articles containing pertinent information and formulated two strings (one more specific, one more sensitive) for the detection of articles focusing on the etiology of HPD, that were then applied to retrieve articles identifying possible etiologic associations between HPD and three diseases (malaria, LHON and celiac disease) considered not associated to HPD, and define the number of abstracts needed to read (NNR) to find one potentially pertinent article. We propose two strings: one sensitive string derived from the combination of articles providing the largest literature coverage in the field and one specific including combined terms retrieving ≥40% of potentially pertinent articles. NNR were 2.1 and 1.6 for malaria, 3.36 and 2.29 for celiac disease, 2.8 and 2.2 for LHON, respectively. For the first time, two reliable, readily applicable strings are proposed for the retrieval of medical literature assessing putative etiologic associations between HPD and other medical conditions of interest.

  9. Optimal search strategies for detecting cost and economic studies in EMBASE

    Directory of Open Access Journals (Sweden)

    Haynes R Brian

    2006-06-01

    Full Text Available Abstract Background Economic evaluations in the medical literature compare competing diagnosis or treatment methods for their use of resources and their expected outcomes. The best evidence currently available from research regarding both cost and economic comparisons will continue to expand as this type of information becomes more important in today's clinical practice. Researchers and clinicians need quick, reliable ways to access this information. A key source of this type of information is large bibliographic databases such as EMBASE. The objective of this study was to develop search strategies that optimize the retrieval of health costs and economics studies from EMBASE. Methods We conducted an analytic survey, comparing hand searches of journals with retrievals from EMBASE for candidate search terms and combinations. 6 research assistants read all issues of 55 journals indexed by EMBASE for the publishing year 2000. We rated all articles using purpose and quality indicators and categorized them into clinically relevant original studies, review articles, general papers, or case reports. The original and review articles were then categorized for purpose (i.e., cost and economics and other clinical topics and depending on the purpose as 'pass' or 'fail' for methodologic rigor. Candidate search strategies were developed for economic and cost studies, then run in the 55 EMBASE journals, the retrievals being compared with the hand search data. The sensitivity, specificity, precision, and accuracy of the search strategies were calculated. Results Combinations of search terms for detecting both cost and economic studies attained levels of 100% sensitivity with specificity levels of 92.9% and 92.3% respectively. When maximizing for both sensitivity and specificity, the combination of terms for detecting cost studies (sensitivity increased 2.2% over the single term but at a slight decrease in specificity of 0.9%. The maximized combination of terms

  10. Computational prediction of muon stopping sites using ab initio random structure searching (AIRSS)

    Science.gov (United States)

    Liborio, Leandro; Sturniolo, Simone; Jochym, Dominik

    2018-04-01

    The stopping site of the muon in a muon-spin relaxation experiment is in general unknown. There are some techniques that can be used to guess the muon stopping site, but they often rely on approximations and are not generally applicable to all cases. In this work, we propose a purely theoretical method to predict muon stopping sites in crystalline materials from first principles. The method is based on a combination of ab initio calculations, random structure searching, and machine learning, and it has successfully predicted the MuT and MuBC stopping sites of muonium in Si, diamond, and Ge, as well as the muonium stopping site in LiF, without any recourse to experimental results. The method makes use of Soprano, a Python library developed to aid ab initio computational crystallography, that was publicly released and contains all the software tools necessary to reproduce our analysis.

  11. Solving the wind farm layout optimization problem using random search algorithm

    DEFF Research Database (Denmark)

    Feng, Ju; Shen, Wen Zhong

    2015-01-01

    , in which better results than the genetic algorithm (GA) and the old version of the RS algorithm are obtained. Second it is applied to the Horns Rev 1 WF, and the optimized layouts obtain a higher power production than its original layout, both for the real scenario and for two constructed scenarios......Wind farm (WF) layout optimization is to find the optimal positions of wind turbines (WTs) inside a WF, so as to maximize and/or minimize a single objective or multiple objectives, while satisfying certain constraints. In this work, a random search (RS) algorithm based on continuous formulation....... In this application, it is also found that in order to get consistent and reliable optimization results, up to 360 or more sectors for wind direction have to be used. Finally, considering the inevitable inter-annual variations in the wind conditions, the robustness of the optimized layouts against wind condition...

  12. Librarian co-authors correlated with higher quality reported search strategies in general internal medicine systematic reviews.

    Science.gov (United States)

    Rethlefsen, Melissa L; Farrell, Ann M; Osterhaus Trzasko, Leah C; Brigham, Tara J

    2015-06-01

    To determine whether librarian and information specialist authorship was associated with better reported systematic review (SR) search quality. SRs from high-impact general internal medicine journals were reviewed for search quality characteristics and reporting quality by independent reviewers using three instruments, including a checklist of Institute of Medicine Recommended Standards for the Search Process and a scored modification of the Peer Review of Electronic Search Strategies instrument. The level of librarian and information specialist participation was significantly associated with search reproducibility from reported search strategies (Χ(2) = 23.5; P Librarian co-authored SRs had significantly higher odds of meeting 8 of 13 analyzed search standards than those with no librarian participation and six more than those with mentioned librarian participation. One-way ANOVA showed that differences in total search quality scores between all three groups were statistically significant (F2,267 = 10.1233; P librarian or information specialist co-authors are correlated with significantly higher quality reported search strategies. To minimize bias in SRs, authors and editors could encourage librarian engagement in SRs including authorship as a potential way to help improve documentation of the search strategy. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Ab initio random structure search for 13-atom clusters of fcc elements

    International Nuclear Information System (INIS)

    Chou, J P; Hsing, C R; Wei, C M; Cheng, C; Chang, C M

    2013-01-01

    The 13-atom metal clusters of fcc elements (Al, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au) were studied by density functional theory calculations. The global minima were searched for by the ab initio random structure searching method. In addition to some new lowest-energy structures for Pd 13 and Au 13 , we found that the effective coordination numbers of the lowest-energy clusters would increase with the ratio of the dimer-to-bulk bond length. This correlation, together with the electronic structures of the lowest-energy clusters, divides the 13-atom clusters of these fcc elements into two groups (except for Au 13 , which prefers a two-dimensional structure due to the relativistic effect). Compact-like clusters that are composed exclusively of triangular motifs are preferred for elements without d-electrons (Al) or with (nearly) filled d-band electrons (Ni, Pd, Cu, Ag). Non-compact clusters composed mainly of square motifs connected by some triangular motifs (Rh, Ir, Pt) are favored for elements with unfilled d-band electrons. (paper)

  14. Optimal Control Strategy Search Using a Simplest 3-D PWR Xenon Oscillation Simulator

    International Nuclear Information System (INIS)

    Yoichiro, Shimazu

    2004-01-01

    Power spatial oscillations due to the transient xenon spatial distribution are well known as xenon oscillation in large PWRs. When the reactor size becomes larger than the current design, then even radial oscillations can be also divergent. Even if the radial oscillation is convergent, when some control rods malfunction occurs, it is necessary to suppress the oscillation in as short time as possible. In such cases, optimal control strategy is required. Generally speaking the optimality search based on the modern control theory requires a lot of calculation for the evaluation of state variables. In the case of control rod malfunctions the xenon oscillation could be three dimensional. In such case, direct core calculations would be inevitable. From this point of view a very simple model, only four point reactor model, has been developed and verified. In this paper, an example of a procedure and the results for optimal control strategy search are presented. It is shown that we have only one optimal strategy within a half cycle of the oscillation with fixed control strength. It is also shown that a 3-D xenon oscillation introduced by a control rod malfunction can not be controlled by only one control step as can be done for axial oscillations. They might be quite strong limitations to the operators. Thus it is recommended that a strategy generator, which is quick in analyzing and easy to use, might be installed in a monitoring system or operator guiding system. (author)

  15. Online strategies to facilitate health-related knowledge transfer: a systematic search and review.

    Science.gov (United States)

    Mairs, Katie; McNeil, Heather; McLeod, Jordache; Prorok, Jeanette C; Stolee, Paul

    2013-12-01

    Health interventions and practices often lag behind the available research, and the need for timely translation of new health knowledge into practice is becoming increasingly important. The objective of this study was to conduct a systematic search and review of the literature on online knowledge translation techniques that foster the interaction between various stakeholders and assist in the sharing of ideas and knowledge within the health field. The search strategy included all published literature in the English language since January 2003 and used the medline, Cumulative Index to Nursing and Allied Health Literature (cinahl), embase and Inspec databases. The results of the review indicate that online strategies are diverse, yet all are applicable in facilitating online health-related knowledge translation. The method of knowledge sharing ranged from use of wikis, discussion forums, blogs, and social media to data/knowledge management tools, virtual communities of practice and conferencing technology - all of which can encourage online health communication and knowledge translation. Online technologies are a key facilitator of health-related knowledge translation. This review of online strategies to facilitate health-related knowledge translation can inform the development and improvement of future strategies to expedite the translation of research to practice. © 2013 Health Libraries Group of CILIP and John Wiley & Sons Ltd.

  16. Validation of a search strategy to identify nutrition trials in PubMed using the relative recall method.

    Science.gov (United States)

    Durão, Solange; Kredo, Tamara; Volmink, Jimmy

    2015-06-01

    To develop, assess, and maximize the sensitivity of a search strategy to identify diet and nutrition trials in PubMed using relative recall. We developed a search strategy to identify diet and nutrition trials in PubMed. We then constructed a gold standard reference set to validate the identified trials using the relative recall method. Relative recall was calculated by dividing the number of references from the gold standard our search strategy identified by the total number of references in the gold standard. Our gold standard comprised 298 trials, derived from 16 included systematic reviews. The initial search strategy identified 242 of 298 references, with a relative recall of 81.2% [95% confidence interval (CI): 76.3%, 85.5%]. We analyzed titles and abstracts of the 56 missed references for possible additional terms. We then modified the search strategy accordingly. The relative recall of the final search strategy was 88.6% (95% CI: 84.4%, 91.9%). We developed a search strategy to identify diet and nutrition trials in PubMed with a high relative recall (sensitivity). This could be useful for establishing a nutrition trials register to support the conduct of future research, including systematic reviews. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  17. Random intermittent search and the tug-of-war model of motor-driven transport

    International Nuclear Information System (INIS)

    Newby, Jay; Bressloff, Paul C

    2010-01-01

    We formulate the 'tug-of-war' model of microtubule cargo transport by multiple molecular motors as an intermittent random search for a hidden target. A motor complex consisting of multiple molecular motors with opposing directional preference is modeled using a discrete Markov process. The motors randomly pull each other off of the microtubule so that the state of the motor complex is determined by the number of bound motors. The tug-of-war model prescribes the state transition rates and corresponding cargo velocities in terms of experimentally measured physical parameters. We add space to the resulting Chapman–Kolmogorov (CK) equation so that we can consider delivery of the cargo to a hidden target at an unknown location along the microtubule track. The target represents some subcellular compartment such as a synapse in a neuron's dendrites, and target delivery is modeled as a simple absorption process. Using a quasi-steady-state (QSS) reduction technique we calculate analytical approximations of the mean first passage time (MFPT) to find the target. We show that there exists an optimal adenosine triphosphate (ATP) concentration that minimizes the MFPT for two different cases: (i) the motor complex is composed of equal numbers of kinesin motors bound to two different microtubules (symmetric tug-of-war model) and (ii) the motor complex is composed of different numbers of kinesin and dynein motors bound to a single microtubule (asymmetric tug-of-war model)

  18. Random intermittent search and the tug-of-war model of motor-driven transport

    Science.gov (United States)

    Newby, Jay; Bressloff, Paul C.

    2010-04-01

    We formulate the 'tug-of-war' model of microtubule cargo transport by multiple molecular motors as an intermittent random search for a hidden target. A motor complex consisting of multiple molecular motors with opposing directional preference is modeled using a discrete Markov process. The motors randomly pull each other off of the microtubule so that the state of the motor complex is determined by the number of bound motors. The tug-of-war model prescribes the state transition rates and corresponding cargo velocities in terms of experimentally measured physical parameters. We add space to the resulting Chapman-Kolmogorov (CK) equation so that we can consider delivery of the cargo to a hidden target at an unknown location along the microtubule track. The target represents some subcellular compartment such as a synapse in a neuron's dendrites, and target delivery is modeled as a simple absorption process. Using a quasi-steady-state (QSS) reduction technique we calculate analytical approximations of the mean first passage time (MFPT) to find the target. We show that there exists an optimal adenosine triphosphate (ATP) concentration that minimizes the MFPT for two different cases: (i) the motor complex is composed of equal numbers of kinesin motors bound to two different microtubules (symmetric tug-of-war model) and (ii) the motor complex is composed of different numbers of kinesin and dynein motors bound to a single microtubule (asymmetric tug-of-war model).

  19. Random intermittent search and the tug-of-war model of motor-driven transport

    KAUST Repository

    Newby, Jay

    2010-04-16

    We formulate the \\'tug-of-war\\' model of microtubule cargo transport by multiple molecular motors as an intermittent random search for a hidden target. A motor complex consisting of multiple molecular motors with opposing directional preference is modeled using a discrete Markov process. The motors randomly pull each other off of the microtubule so that the state of the motor complex is determined by the number of bound motors. The tug-of-war model prescribes the state transition rates and corresponding cargo velocities in terms of experimentally measured physical parameters. We add space to the resulting Chapman-Kolmogorov (CK) equation so that we can consider delivery of the cargo to a hidden target at an unknown location along the microtubule track. The target represents some subcellular compartment such as a synapse in a neuron\\'s dendrites, and target delivery is modeled as a simple absorption process. Using a quasi-steady-state (QSS) reduction technique we calculate analytical approximations of the mean first passage time (MFPT) to find the target. We show that there exists an optimal adenosine triphosphate (ATP) concentration that minimizes the MFPT for two different cases: (i) the motor complex is composed of equal numbers of kinesin motors bound to two different microtubules (symmetric tug-of-war model) and (ii) the motor complex is composed of different numbers of kinesin and dynein motors bound to a single microtubule (asymmetric tug-of-war model). © 2010 IOP Publishing Ltd.

  20. Random intermittent search and the tug-of-war model of motor-driven transport

    KAUST Repository

    Newby, Jay; Bressloff, Paul C

    2010-01-01

    We formulate the 'tug-of-war' model of microtubule cargo transport by multiple molecular motors as an intermittent random search for a hidden target. A motor complex consisting of multiple molecular motors with opposing directional preference is modeled using a discrete Markov process. The motors randomly pull each other off of the microtubule so that the state of the motor complex is determined by the number of bound motors. The tug-of-war model prescribes the state transition rates and corresponding cargo velocities in terms of experimentally measured physical parameters. We add space to the resulting Chapman-Kolmogorov (CK) equation so that we can consider delivery of the cargo to a hidden target at an unknown location along the microtubule track. The target represents some subcellular compartment such as a synapse in a neuron's dendrites, and target delivery is modeled as a simple absorption process. Using a quasi-steady-state (QSS) reduction technique we calculate analytical approximations of the mean first passage time (MFPT) to find the target. We show that there exists an optimal adenosine triphosphate (ATP) concentration that minimizes the MFPT for two different cases: (i) the motor complex is composed of equal numbers of kinesin motors bound to two different microtubules (symmetric tug-of-war model) and (ii) the motor complex is composed of different numbers of kinesin and dynein motors bound to a single microtubule (asymmetric tug-of-war model). © 2010 IOP Publishing Ltd.

  1. The Impact of Competencies, Information Search, and Competitive Strategy on the Export Performance

    Directory of Open Access Journals (Sweden)

    Lena Elitan

    2011-04-01

    Full Text Available This confirmatory study is aimed at analyzing the impact of relationships, information search, and competencies on competitive strategy and SMEs performance in Indonesia. The study used 100 SMEs samples that obtained through mailed questionnaires. The results show: Firstly, the perception of information, information sources, and export competence has no significant effect on competitive strategy. However the findings for SMEs in Indonesia, indicated that export related information has negative effects on competitive strategy. Secondly, export competencies has an enormous influence on the company’s capacity and ability to use information appropriately, when the company must deal with challenges or when the company is eager to take advantage of the opportunities to increase growth and profitability. Thirdly, competitive strategy does not directly affect export performance but it is moderated by the environment uncertainty. It indicates that the influence of competitive strategy would be greater in an uncertain business environment. The uncertain business environment will encourage companies to explore competitive strategy to improve their performance.

  2. The Impact of Competencies, Information Search, and Competitive Strategy on the Export Performance

    Directory of Open Access Journals (Sweden)

    Lena Elitan

    2011-04-01

    Full Text Available This confirmatory study is aimed at analyzing the impact of relationships, information search, and competencies on competitive strategy and SMEs performance in Indonesia. The study used 100 SMEs samples that obtained through mailed questionnaires. The results show: Firstly, the perception of information, information sources, and export competence has no significant effect on competitive strategy. However the findings for SMEs in Indonesia, indicated that export related information has negative effects on competitive strategy. Secondly, export competencies has an enormous influence on the company’s capacity and ability to use information appropriately,when the company must deal with challenges or when the company is eager to take advantage of the opportunities to increase growth and profitability. Thirdly, competitive strategy does not directly affect export performance but it is moderated by the environment uncertainty. It indicates that the influence of competitive strategy would be greater in an uncertain business environment. The uncertain business environment will encourage companies to explore competitive strategy to improve their performance.

  3. Stochastic foundations in movement ecology anomalous diffusion, front propagation and random searches

    CERN Document Server

    Méndez, Vicenç; Bartumeus, Frederic

    2014-01-01

    This book presents the fundamental theory for non-standard diffusion problems in movement ecology. Lévy processes and anomalous diffusion have shown to be both powerful and useful tools for qualitatively and quantitatively describing a wide variety of spatial population ecological phenomena and dynamics, such as invasion fronts and search strategies. Adopting a self-contained, textbook-style approach, the authors provide the elements of statistical physics and stochastic processes on which the modeling of movement ecology is based and systematically introduce the physical characterization of ecological processes at the microscopic, mesoscopic and macroscopic levels. The explicit definition of these levels and their interrelations is particularly suitable to coping with the broad spectrum of space and time scales involved in bio-ecological problems.   Including numerous exercises (with solutions), this text is aimed at graduate students and newcomers in this field at the interface of theoretical ecology, mat...

  4. Comparison of the efficacy of three PubMed search filters in finding randomized controlled trials to answer clinical questions.

    Science.gov (United States)

    Yousefi-Nooraie, Reza; Irani, Shirin; Mortaz-Hedjri, Soroush; Shakiba, Behnam

    2013-10-01

    The aim of this study was to compare the performance of three search methods in the retrieval of relevant clinical trials from PubMed to answer specific clinical questions. Included studies of a sample of 100 Cochrane reviews which recorded in PubMed were considered as the reference standard. The search queries were formulated based on the systematic review titles. Precision, recall and number of retrieved records for limiting the results to clinical trial publication type, and using sensitive and specific clinical queries filters were compared. The number of keywords, presence of specific names of intervention and syndrome in the search keywords were used in a model to predict the recalls and precisions. The Clinical queries-sensitive search strategy retrieved the largest number of records (33) and had the highest recall (41.6%) and lowest precision (4.8%). The presence of specific intervention name was the only significant predictor of all recalls and precisions (P = 0.016). The recall and precision of combination of simple clinical search queries and methodological search filters to find clinical trials in various subjects were considerably low. The limit field strategy yielded in higher precision and fewer retrieved records and approximately similar recall, compared with the clinical queries-sensitive strategy. Presence of specific intervention name in the search keywords increased both recall and precision. © 2010 John Wiley & Sons Ltd.

  5. Optimal strategy analysis based on robust predictive control for inventory system with random demand

    Science.gov (United States)

    Saputra, Aditya; Widowati, Sutrisno

    2017-12-01

    In this paper, the optimal strategy for a single product single supplier inventory system with random demand is analyzed by using robust predictive control with additive random parameter. We formulate the dynamical system of this system as a linear state space with additive random parameter. To determine and analyze the optimal strategy for the given inventory system, we use robust predictive control approach which gives the optimal strategy i.e. the optimal product volume that should be purchased from the supplier for each time period so that the expected cost is minimal. A numerical simulation is performed with some generated random inventory data. We simulate in MATLAB software where the inventory level must be controlled as close as possible to a set point decided by us. From the results, robust predictive control model provides the optimal strategy i.e. the optimal product volume that should be purchased and the inventory level was followed the given set point.

  6. Comparing Exploration Strategies for Q-learning in Random Stochastic Mazes

    NARCIS (Netherlands)

    Tijsma, Arryon; Drugan, Madalina; Wiering, Marco

    2016-01-01

    Balancing the ratio between exploration and exploitation is an important problem in reinforcement learning. This paper evaluates four different exploration strategies combined with Q-learning using random stochastic mazes to investigate their performances. We will compare: UCB-1, softmax,

  7. Search strategies for pair production of heavy Higgs bosons decaying invisibly at the LHC

    Science.gov (United States)

    Arganda, E.; Diaz-Cruz, J. L.; Mileo, N.; Morales, R. A.; Szynkman, A.

    2018-04-01

    The search for heavy Higgs bosons at the LHC represents an intense experimental program, carried out by the ATLAS and CMS collaborations, which includes the hunt for invisible Higgs decays and dark matter candidates. No significant deviations from the SM backgrounds have been observed in any of these searches, imposing significant constraints on the parameter space of different new physics models with an extended Higgs sector. Here we discuss an alternative search strategy for heavy Higgs bosons decaying invisibly at the LHC, focusing on the pair production of a heavy scalar H together with a pseudoscalar A, through the production mode q q bar →Z* → HA. We identify as the most promising signal the final state made up of 4 b +ET miss, coming from the heavy scalar decay mode H → hh → b b bar b b bar , with h being the discovered SM-like Higgs boson with mh = 125GeV, together with the invisible channel of the pseudoscalar. We work within the context of simplified MSSM scenarios that contain quite heavy sfermions of most types with O (10)TeV masses, while the stops are heavy enough to reproduce the 125 GeV mass for the lightest SM-like Higgs boson. By contrast, the gauginos/higgsinos and the heavy MSSM Higgs bosons have masses near the EW scale. Our search strategies, for a LHC center-of-mass energy of √{ s } = 14TeV, allow us to obtain statistical significances of the signal over the SM backgrounds with values up to ∼ 1.6 σ and ∼ 3 σ, for total integrated luminosities of 300fb-1 and 1000fb-1, respectively.

  8. SOME SYSTEMATIC SAMPLING STRATEGIES USING MULTIPLE RANDOM STARTS

    OpenAIRE

    Sampath Sundaram; Ammani Sivaraman

    2010-01-01

    In this paper an attempt is made to extend linear systematic sampling using multiple random starts due to Gautschi(1957)for various types of systematic sampling schemes available in literature, namely(i)  Balanced Systematic Sampling (BSS) of  Sethi (1965) and (ii) Modified Systematic Sampling (MSS) of Singh, Jindal, and Garg  (1968). Further, the proposed methods were compared with Yates corrected estimator developed with reference to Gautschi’s Linear systematic samplin...

  9. Intermittent search strategies revisited: effect of the jump length and biased motion

    Energy Technology Data Exchange (ETDEWEB)

    Rojo, F; Budde, C E [Fa.M.A.F., Universidad Nacional de Cordoba, Ciudad Universitaria, X5000HUA Cordoba (Argentina); Revelli, J; Wio, H S [Instituto de Fisica de Cantabria, Universidad de Cantabria and CSIC, E-39005 Santander (Spain); Oshanin, G [Laboratoire de Physique Theorique de la Matiere Condensee, Universite Pierre et Marie Curie, 4 place Jussieu, 75252 Paris Cedex 5 (France); Lindenberg, Katja [Department of Chemistry and Biochemistry and BioCircuits Institute, University of California, San Diego, La Jolla, CA 92093-0340 (United States)

    2010-08-27

    We study the kinetics of a search of a single fixed target by a large number of searchers performing an intermittent biased random walk in a homogeneous medium. Our searchers carry out their walks in one of two states between which they switch randomly. One of these states (search phase) is a nearest-neighbor walk characterized by the probability of stepping in a given direction (i.e. the walks in this state are not necessarily isotropic). The other (relocation phase) is characterized by the length of the jumps (i.e. when in this state a walker does not perform a nearest-neighbor walk). Within such a framework, we propose a model to describe the searchers' dynamics, generalizing results of our previous work. We have obtained, and numerically evaluated, analytic results for the mean number of distinct sites visited up to a maximum evolution time. We have studied the dependence of this quantity on both the transition probability between the states and the parameters that characterize each state. In addition to our theoretical approach, we have implemented Monte Carlo simulations, finding excellent agreement between the theoretical-numerical and simulations results.

  10. Intermittent search strategies revisited: effect of the jump length and biased motion

    International Nuclear Information System (INIS)

    Rojo, F; Budde, C E; Revelli, J; Wio, H S; Oshanin, G; Lindenberg, Katja

    2010-01-01

    We study the kinetics of a search of a single fixed target by a large number of searchers performing an intermittent biased random walk in a homogeneous medium. Our searchers carry out their walks in one of two states between which they switch randomly. One of these states (search phase) is a nearest-neighbor walk characterized by the probability of stepping in a given direction (i.e. the walks in this state are not necessarily isotropic). The other (relocation phase) is characterized by the length of the jumps (i.e. when in this state a walker does not perform a nearest-neighbor walk). Within such a framework, we propose a model to describe the searchers' dynamics, generalizing results of our previous work. We have obtained, and numerically evaluated, analytic results for the mean number of distinct sites visited up to a maximum evolution time. We have studied the dependence of this quantity on both the transition probability between the states and the parameters that characterize each state. In addition to our theoretical approach, we have implemented Monte Carlo simulations, finding excellent agreement between the theoretical-numerical and simulations results.

  11. Literature search strategies for interdisciplinary research a sourcebook for scientists and engineers

    CERN Document Server

    Ackerson, Linda G

    2006-01-01

    The amount of published literature can be overwhelming for scientists and researchers moving from a broad disciplinary research area to a more specialized one, particularly in fields that use information from more than one discipline. Without a focused inquiry, the researcher may find too little information or may be overcome by too much. Striking the correct balance of information is the focus of Literature Search Strategies for Interdisciplinary Research. This useful reference tool studies diverse interdisciplinary areas revealing the general and individual qualities that dictate the strateg

  12. Making sense of the future: The information search strategies of construction practitioners in exploring the risk landscape

    DEFF Research Database (Denmark)

    Stingl, Verena; Maytorena-Sanchez, Eunice

    This paper explores the cognitive strategies that construction practitioners rely on when searching to identify risks in a simulated project. By using the active information search methodology in interviews with 45 industry practitioners, we were able to distinguish three stereotypical information...

  13. Web-Based Undergraduate Chemistry Problem-Solving: The Interplay of Task Performance, Domain Knowledge and Web-Searching Strategies

    Science.gov (United States)

    She, Hsiao-Ching; Cheng, Meng-Tzu; Li, Ta-Wei; Wang, Chia-Yu; Chiu, Hsin-Tien; Lee, Pei-Zon; Chou, Wen-Chi; Chuang, Ming-Hua

    2012-01-01

    This study investigates the effect of Web-based Chemistry Problem-Solving, with the attributes of Web-searching and problem-solving scaffolds, on undergraduate students' problem-solving task performance. In addition, the nature and extent of Web-searching strategies students used and its correlation with task performance and domain knowledge also…

  14. Design, rationale, and baseline demographics of SEARCH I: a prospective cluster-randomized study

    Directory of Open Access Journals (Sweden)

    Albers F

    2012-07-01

    Full Text Available Frank Albers,1 Asif Shaikh,2 Ahmar Iqbal,31Medical Affairs Respiratory, 2Clinical Development and Medical Affairs, Field Based Medicine-Respiratory, Boehringer Ingelheim Pharmaceuticals, Inc, Ridgefield, CT, USA; 3Respiratory Medical Affairs, Pfizer Inc, New York, NY, USAAbstract: Questionnaires are available to identify patients at risk for several chronic diseases, including COPD, but are infrequently utilized in primary care. COPD is often underdiagnosed, while at the same time the US Preventive Services Task Force recommends against spirometric screening for COPD in asymptomatic adults. Use of a symptom-based questionnaire and subsequent handheld spirometric device depending on the answers to the questionnaire is a promising approach to identify patients at risk for COPD. Screening, Evaluating and Assessing Rate CHanges of diagnosing respiratory conditions in primary care 1 (SEARCH I was a prospective cluster-randomized study in 168 US primary care practices evaluating the effect of the COPD-Population Screener (COPD-PS™ questionnaire. The effect of this questionnaire alone or sequentially with the handheld copd-6TM device was evaluated on new diagnoses of COPD and on respiratory diagnostic practice patterns (including referrals for pulmonary function testing, referrals to pulmonologists, new diagnoses of COPD, and new respiratory medication prescriptions. Participating practices entered a total of 9704 consecutive consenting subjects aged ≥ 40 years attending primary care clinics. Study arm results were compared for new COPD diagnosis rates between usual care and (1 COPD-PS plus copd-6 and (2 COPD-PS alone. A cluster-randomization design allowed comparison of the intervention effects at the practice level instead of individuals being the subjects of the intervention. Regional principal investigators controlled the flow of study information to sub-investigators at participating practices to reduce observation bias (Hawthorne effect. The

  15. Locating qualitative studies in dementia on MEDLINE, EMBASE, CINAHL, and PsycINFO: A comparison of search strategies.

    Science.gov (United States)

    Rogers, Morwenna; Bethel, Alison; Abbott, Rebecca

    2017-10-28

    Qualitative research in dementia improves understanding of the experience of people affected by dementia. Searching databases for qualitative studies is problematic. Qualitative-specific search strategies might help with locating studies. To examine the effectiveness (sensitivity and precision) of 5 qualitative strategies on locating qualitative research studies in dementia in 4 major databases (MEDLINE, EMBASE, PsycINFO, and CINAHL). Qualitative dementia studies were checked for inclusion on MEDLINE, EMBASE, PsycINFO, and CINAHL. Five qualitative search strategies (subject headings, simple free-text terms, complex free-text terms, and 2 broad-based strategies) were tested for study retrieval. Specificity, precision and number needed to read were calculated. Two hundred fourteen qualitative studies in dementia were included. PsycINFO and CINAHL held the most qualitative studies out the 4 databases studied (N = 171 and 166, respectively) and both held unique records (N = 14 and 7, respectively). The controlled vocabulary strategy in CINAHL returned 96% (N = 192) of studies held; by contrast, controlled vocabulary in PsycINFO returned 7% (N = 13) of studies held. The broad-based strategies returned more studies (93-99%) than the other free-text strategies (22-82%). Precision ranged from 0.061 to 0.004 resulting in a number needed to read to obtain 1 relevant study ranging from 16 (simple free-text search in CINAHL) to 239 (broad-based search in EMBASE). Qualitative search strategies using 3 broad terms were more sensitive than long complex searches. The controlled vocabulary for qualitative research in CINAHL was particularly effective. Furthermore, results indicate that MEDLINE and EMBASE offer little benefit for locating qualitative dementia research if CINAHL and PSYCINFO are also searched. Copyright © 2017 John Wiley & Sons, Ltd.

  16. A simple heuristic for Internet-based evidence search in primary care: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Eberbach A

    2016-08-01

    Full Text Available Andreas Eberbach,1 Annette Becker,1 Justine Rochon,2 Holger Finkemeler,1Achim Wagner,3 Norbert Donner-Banzhoff1 1Department of Family and Community Medicine, Philipp University of Marburg, Marburg, Germany; 2Institute of Medical Biometry and Informatics, University of Heidelberg, Heidelberg, Germany; 3Department of Sport Medicine, Justus-Liebig-University of Giessen, Giessen, Germany Background: General practitioners (GPs are confronted with a wide variety of clinical questions, many of which remain unanswered. Methods: In order to assist GPs in finding quick, evidence-based answers, we developed a learning program (LP with a short interactive workshop based on a simple ­three-step-heuristic to improve their search and appraisal competence (SAC. We evaluated the LP ­effectiveness with a randomized controlled trial (RCT. Participants (intervention group [IG] n=20; ­control group [CG] n=31 rated acceptance and satisfaction and also answered 39 ­knowledge ­questions to assess their SAC. We controlled for previous knowledge in content areas covered by the test. Results: Main outcome – SAC: within both groups, the pre–post test shows significant (P=0.00 improvements in correctness (IG 15% vs CG 11% and confidence (32% vs 26% to find evidence-based answers. However, the SAC difference was not significant in the RCT. Other measures: Most workshop participants rated “learning atmosphere” (90%, “skills acquired” (90%, and “relevancy to my practice” (86% as good or very good. The ­LP-recommendations were implemented by 67% of the IG, whereas 15% of the CG already conformed to LP recommendations spontaneously (odds ratio 9.6, P=0.00. After literature search, the IG showed a (not significantly higher satisfaction regarding “time spent” (IG 80% vs CG 65%, “quality of information” (65% vs 54%, and “amount of information” (53% vs 47%.Conclusion: Long-standing established GPs have a good SAC. Despite high acceptance, strong

  17. Blind Channel Equalization Using Constrained Generalized Pattern Search Optimization and Reinitialization Strategy

    Directory of Open Access Journals (Sweden)

    Charles Tatkeu

    2008-12-01

    Full Text Available We propose a global convergence baud-spaced blind equalization method in this paper. This method is based on the application of both generalized pattern optimization and channel surfing reinitialization. The potentially used unimodal cost function relies on higher- order statistics, and its optimization is achieved using a pattern search algorithm. Since the convergence to the global minimum is not unconditionally warranted, we make use of channel surfing reinitialization (CSR strategy to find the right global minimum. The proposed algorithm is analyzed, and simulation results using a severe frequency selective propagation channel are given. Detailed comparisons with constant modulus algorithm (CMA are highlighted. The proposed algorithm performances are evaluated in terms of intersymbol interference, normalized received signal constellations, and root mean square error vector magnitude. In case of nonconstant modulus input signals, our algorithm outperforms significantly CMA algorithm with full channel surfing reinitialization strategy. However, comparable performances are obtained for constant modulus signals.

  18. Blind Channel Equalization Using Constrained Generalized Pattern Search Optimization and Reinitialization Strategy

    Science.gov (United States)

    Zaouche, Abdelouahib; Dayoub, Iyad; Rouvaen, Jean Michel; Tatkeu, Charles

    2008-12-01

    We propose a global convergence baud-spaced blind equalization method in this paper. This method is based on the application of both generalized pattern optimization and channel surfing reinitialization. The potentially used unimodal cost function relies on higher- order statistics, and its optimization is achieved using a pattern search algorithm. Since the convergence to the global minimum is not unconditionally warranted, we make use of channel surfing reinitialization (CSR) strategy to find the right global minimum. The proposed algorithm is analyzed, and simulation results using a severe frequency selective propagation channel are given. Detailed comparisons with constant modulus algorithm (CMA) are highlighted. The proposed algorithm performances are evaluated in terms of intersymbol interference, normalized received signal constellations, and root mean square error vector magnitude. In case of nonconstant modulus input signals, our algorithm outperforms significantly CMA algorithm with full channel surfing reinitialization strategy. However, comparable performances are obtained for constant modulus signals.

  19. Decision making in family medicine: randomized trial of the effects of the InfoClinique and Trip database search engines.

    Science.gov (United States)

    Labrecque, Michel; Ratté, Stéphane; Frémont, Pierre; Cauchon, Michel; Ouellet, Jérôme; Hogg, William; McGowan, Jessie; Gagnon, Marie-Pierre; Njoya, Merlin; Légaré, France

    2013-10-01

    To compare the ability of users of 2 medical search engines, InfoClinique and the Trip database, to provide correct answers to clinical questions and to explore the perceived effects of the tools on the clinical decision-making process. Randomized trial. Three family medicine units of the family medicine program of the Faculty of Medicine at Laval University in Quebec city, Que. Fifteen second-year family medicine residents. Residents generated 30 structured questions about therapy or preventive treatment (2 questions per resident) based on clinical encounters. Using an Internet platform designed for the trial, each resident answered 20 of these questions (their own 2, plus 18 of the questions formulated by other residents, selected randomly) before and after searching for information with 1 of the 2 search engines. For each question, 5 residents were randomly assigned to begin their search with InfoClinique and 5 with the Trip database. The ability of residents to provide correct answers to clinical questions using the search engines, as determined by third-party evaluation. After answering each question, participants completed a questionnaire to assess their perception of the engine's effect on the decision-making process in clinical practice. Of 300 possible pairs of answers (1 answer before and 1 after the initial search), 254 (85%) were produced by 14 residents. Of these, 132 (52%) and 122 (48%) pairs of answers concerned questions that had been assigned an initial search with InfoClinique and the Trip database, respectively. Both engines produced an important and similar absolute increase in the proportion of correct answers after searching (26% to 62% for InfoClinique, for an increase of 36%; 24% to 63% for the Trip database, for an increase of 39%; P = .68). For all 30 clinical questions, at least 1 resident produced the correct answer after searching with either search engine. The mean (SD) time of the initial search for each question was 23.5 (7

  20. Radiotherapy Planning Using an Improved Search Strategy in Particle Swarm Optimization.

    Science.gov (United States)

    Modiri, Arezoo; Gu, Xuejun; Hagan, Aaron M; Sawant, Amit

    2017-05-01

    Evolutionary stochastic global optimization algorithms are widely used in large-scale, nonconvex problems. However, enhancing the search efficiency and repeatability of these techniques often requires well-customized approaches. This study investigates one such approach. We use particle swarm optimization (PSO) algorithm to solve a 4D radiation therapy (RT) inverse planning problem, where the key idea is to use respiratory motion as an additional degree of freedom in lung cancer RT. The primary goal is to administer a lethal dose to the tumor target while sparing surrounding healthy tissue. Our optimization iteratively adjusts radiation fluence-weights for all beam apertures across all respiratory phases. We implement three PSO-based approaches: conventionally used unconstrained, hard-constrained, and our proposed virtual search. As proof of concept, five lung cancer patient cases are optimized over ten runs using each PSO approach. For comparison, a dynamically penalized likelihood (DPL) algorithm-a popular RT optimization technique is also implemented and used. The proposed technique significantly improves the robustness to random initialization while requiring fewer iteration cycles to converge across all cases. DPL manages to find the global optimum in 2 out of 5 RT cases over significantly more iterations. The proposed virtual search approach boosts the swarm search efficiency, and consequently, improves the optimization convergence rate and robustness for PSO. RT planning is a large-scale, nonconvex optimization problem, where finding optimal solutions in a clinically practical time is critical. Our proposed approach can potentially improve the optimization efficiency in similar time-sensitive problems.

  1. VES/TEM 1D joint inversion by using Controlled Random Search (CRS) algorithm

    Science.gov (United States)

    Bortolozo, Cassiano Antonio; Porsani, Jorge Luís; Santos, Fernando Acácio Monteiro dos; Almeida, Emerson Rodrigo

    2015-01-01

    Electrical (DC) and Transient Electromagnetic (TEM) soundings are used in a great number of environmental, hydrological, and mining exploration studies. Usually, data interpretation is accomplished by individual 1D models resulting often in ambiguous models. This fact can be explained by the way as the two different methodologies sample the medium beneath surface. Vertical Electrical Sounding (VES) is good in marking resistive structures, while Transient Electromagnetic sounding (TEM) is very sensitive to conductive structures. Another difference is VES is better to detect shallow structures, while TEM soundings can reach deeper layers. A Matlab program for 1D joint inversion of VES and TEM soundings was developed aiming at exploring the best of both methods. The program uses CRS - Controlled Random Search - algorithm for both single and 1D joint inversions. Usually inversion programs use Marquadt type algorithms but for electrical and electromagnetic methods, these algorithms may find a local minimum or not converge. Initially, the algorithm was tested with synthetic data, and then it was used to invert experimental data from two places in Paraná sedimentary basin (Bebedouro and Pirassununga cities), both located in São Paulo State, Brazil. Geoelectric model obtained from VES and TEM data 1D joint inversion is similar to the real geological condition, and ambiguities were minimized. Results with synthetic and real data show that 1D VES/TEM joint inversion better recovers simulated models and shows a great potential in geological studies, especially in hydrogeological studies.

  2. Metagenomic Taxonomy-Guided Database-Searching Strategy for Improving Metaproteomic Analysis.

    Science.gov (United States)

    Xiao, Jinqiu; Tanca, Alessandro; Jia, Ben; Yang, Runqing; Wang, Bo; Zhang, Yu; Li, Jing

    2018-04-06

    Metaproteomics provides a direct measure of the functional information by investigating all proteins expressed by a microbiota. However, due to the complexity and heterogeneity of microbial communities, it is very hard to construct a sequence database suitable for a metaproteomic study. Using a public database, researchers might not be able to identify proteins from poorly characterized microbial species, while a sequencing-based metagenomic database may not provide adequate coverage for all potentially expressed protein sequences. To address this challenge, we propose a metagenomic taxonomy-guided database-search strategy (MT), in which a merged database is employed, consisting of both taxonomy-guided reference protein sequences from public databases and proteins from metagenome assembly. By applying our MT strategy to a mock microbial mixture, about two times as many peptides were detected as with the metagenomic database only. According to the evaluation of the reliability of taxonomic attribution, the rate of misassignments was comparable to that obtained using an a priori matched database. We also evaluated the MT strategy with a human gut microbial sample, and we found 1.7 times as many peptides as using a standard metagenomic database. In conclusion, our MT strategy allows the construction of databases able to provide high sensitivity and precision in peptide identification in metaproteomic studies, enabling the detection of proteins from poorly characterized species within the microbiota.

  3. Family Health Strategy: assessment and reasons for searching of health service by users

    Directory of Open Access Journals (Sweden)

    Loeste de Arruda-Barbosa

    2011-12-01

    Full Text Available Objective: To assess the evaluation of the users regarding the family health services and identify the main reasons that led them to seek such services. Methods: A descriptive study with qualitative approach, carried out in 5 Family Health Units with 25 users of theFamily Health Strategy (FHS of the city of Crato-CE, Brazil. The study took place from March to April 2009. Semi-structured interview was applied and recorded. We used thetechnique of thematic content analysis. Results: We found that the users of the FHS have great dissatisfaction, especially on the organization and access to health services, evaluating the family health as inefficient, although bringing care closer to the population, primarily through home visits. It was clear also that there is a search to the service mainly supported by curative vision and the acquisition of medicines. Conclusions: The subjects evaluate the organization and access to healthcare services as unsatisfactory, but value the actions, when there is a bond with the health team. However, there is still demand for health services, based on the search for medicines and medical consultation. Thus, it is necessary to improve services of the Family Health Strategy in Crato, with a view to ensure quality, accessibilityand greater resolution of health services.

  4. Analytical connection between thresholds and immunization strategies of SIS model in random networks

    Science.gov (United States)

    Zhou, Ming-Yang; Xiong, Wen-Man; Liao, Hao; Wang, Tong; Wei, Zong-Wen; Fu, Zhong-Qian

    2018-05-01

    Devising effective strategies for hindering the propagation of viruses and protecting the population against epidemics is critical for public security and health. Despite a number of studies based on the susceptible-infected-susceptible (SIS) model devoted to this topic, we still lack a general framework to compare different immunization strategies in completely random networks. Here, we address this problem by suggesting a novel method based on heterogeneous mean-field theory for the SIS model. Our method builds the relationship between the thresholds and different immunization strategies in completely random networks. Besides, we provide an analytical argument that the targeted large-degree strategy achieves the best performance in random networks with arbitrary degree distribution. Moreover, the experimental results demonstrate the effectiveness of the proposed method in both artificial and real-world networks.

  5. Scale-free animal movement patterns: Levy walks outperform fractional Brownian motions and fractional Levy motions in random search scenarios

    International Nuclear Information System (INIS)

    Reynolds, A M

    2009-01-01

    The movement patterns of a diverse range of animals have scale-free characteristics. These characteristics provide necessary but not sufficient conditions for the presence of movement patterns that can be approximated by Levy walks. Nevertheless, it has been widely assumed that the occurrence of scale-free animal movements can indeed be attributed to the presence of Levy walks. This is, in part, because it is known that the super-diffusive properties of Levy walks can be advantageous in random search scenarios when searchers have little or no prior knowledge of target locations. However, fractional Brownian motions (fBms) and fractional Levy motions (fLms) are both scale-free and super-diffusive, and so it is possible that these motions rather than Levy walks underlie some or all occurrences of scale-free animal movement patterns. Here this possibility is examined in numerical simulations through a determination of the searching efficiencies of fBm and fLm searches. It is shown that these searches are less efficient than Levy walk searches. This finding does not rule out the possibility that some animals with scale-free movement patterns are executing fBm and fLm searches, but it does make Levy walk searches the more likely possibility.

  6. A hybrid search algorithm for swarm robots searching in an unknown environment.

    Science.gov (United States)

    Li, Shoutao; Li, Lina; Lee, Gordon; Zhang, Hao

    2014-01-01

    This paper proposes a novel method to improve the efficiency of a swarm of robots searching in an unknown environment. The approach focuses on the process of feeding and individual coordination characteristics inspired by the foraging behavior in nature. A predatory strategy was used for searching; hence, this hybrid approach integrated a random search technique with a dynamic particle swarm optimization (DPSO) search algorithm. If a search robot could not find any target information, it used a random search algorithm for a global search. If the robot found any target information in a region, the DPSO search algorithm was used for a local search. This particle swarm optimization search algorithm is dynamic as all the parameters in the algorithm are refreshed synchronously through a communication mechanism until the robots find the target position, after which, the robots fall back to a random searching mode. Thus, in this searching strategy, the robots alternated between two searching algorithms until the whole area was covered. During the searching process, the robots used a local communication mechanism to share map information and DPSO parameters to reduce the communication burden and overcome hardware limitations. If the search area is very large, search efficiency may be greatly reduced if only one robot searches an entire region given the limited resources available and time constraints. In this research we divided the entire search area into several subregions, selected a target utility function to determine which subregion should be initially searched and thereby reduced the residence time of the target to improve search efficiency.

  7. Intelligent energy allocation strategy for PHEV charging station using gravitational search algorithm

    Science.gov (United States)

    Rahman, Imran; Vasant, Pandian M.; Singh, Balbir Singh Mahinder; Abdullah-Al-Wadud, M.

    2014-10-01

    Recent researches towards the use of green technologies to reduce pollution and increase penetration of renewable energy sources in the transportation sector are gaining popularity. The development of the smart grid environment focusing on PHEVs may also heal some of the prevailing grid problems by enabling the implementation of Vehicle-to-Grid (V2G) concept. Intelligent energy management is an important issue which has already drawn much attention to researchers. Most of these works require formulation of mathematical models which extensively use computational intelligence-based optimization techniques to solve many technical problems. Higher penetration of PHEVs require adequate charging infrastructure as well as smart charging strategies. We used Gravitational Search Algorithm (GSA) to intelligently allocate energy to the PHEVs considering constraints such as energy price, remaining battery capacity, and remaining charging time.

  8. An High Resolution Near-Earth Objects Population Enabling Next-Generation Search Strategies

    Science.gov (United States)

    Tricaico, Pasquale; Beshore, E. C.; Larson, S. M.; Boattini, A.; Williams, G. V.

    2010-01-01

    Over the past decade, the dedicated search for kilometer-size near-Earth objects (NEOs), potentially hazardous objects (PHOs), and potential Earth impactors has led to a boost in the rate of discoveries of these objects. The catalog of known NEOs is the fundamental ingredient used to develop a model for the NEOs population, either by assessing and correcting for the observational bias (Jedicke et al., 2002), or by evaluating the migration rates from the NEOs source regions (Bottke et al., 2002). The modeled NEOs population is a necessary tool used to track the progress in the search of large NEOs (Jedicke et al., 2003) and to try to predict the distribution of the ones still undiscovered, as well as to study the sky distribution of potential Earth impactors (Chesley & Spahr, 2004). We present a method to model the NEOs population in all six orbital elements, on a finely grained grid, allowing us the design and test of targeted and optimized search strategies. This method relies on the observational data routinely reported to the Minor Planet Center (MPC) by the Catalina Sky Survey (CSS) and by other active NEO surveys over the past decade, to determine on a nightly basis the efficiency in detecting moving objects as a function of observable quantities including apparent magnitude, rate of motion, airmass, and galactic latitude. The cumulative detection probability is then be computed for objects within a small range in orbital elements and absolute magnitude, and the comparison with the number of know NEOs within the same range allows us to model the population. When propagated to the present epoch and projected on the sky plane, this provides the distribution of the missing large NEOs, PHOs, and potential impactors.

  9. Reduction rules-based search algorithm for opportunistic replacement strategy of multiple life-limited parts

    Directory of Open Access Journals (Sweden)

    Xuyun FU

    2018-01-01

    Full Text Available The opportunistic replacement of multiple Life-Limited Parts (LLPs is a problem widely existing in industry. The replacement strategy of LLPs has a great impact on the total maintenance cost to a lot of equipment. This article focuses on finding a quick and effective algorithm for this problem. To improve the algorithm efficiency, six reduction rules are suggested from the perspectives of solution feasibility, determination of the replacement of LLPs, determination of the maintenance occasion and solution optimality. Based on these six reduction rules, a search algorithm is proposed. This search algorithm can identify one or several optimal solutions. A numerical experiment shows that these six reduction rules are effective, and the time consumed by the algorithm is less than 38 s if the total life of equipment is shorter than 55000 and the number of LLPs is less than 11. A specific case shows that the algorithm can obtain optimal solutions which are much better than the result of the traditional method in 10 s, and it can provide support for determining to-be-replaced LLPs when determining the maintenance workscope of an aircraft engine. Therefore, the algorithm is applicable to engineering applications concerning opportunistic replacement of multiple LLPs in aircraft engines.

  10. Group search optimiser-based optimal bidding strategies with no Karush-Kuhn-Tucker optimality conditions

    Science.gov (United States)

    Yadav, Naresh Kumar; Kumar, Mukesh; Gupta, S. K.

    2017-03-01

    General strategic bidding procedure has been formulated in the literature as a bi-level searching problem, in which the offer curve tends to minimise the market clearing function and to maximise the profit. Computationally, this is complex and hence, the researchers have adopted Karush-Kuhn-Tucker (KKT) optimality conditions to transform the model into a single-level maximisation problem. However, the profit maximisation problem with KKT optimality conditions poses great challenge to the classical optimisation algorithms. The problem has become more complex after the inclusion of transmission constraints. This paper simplifies the profit maximisation problem as a minimisation function, in which the transmission constraints, the operating limits and the ISO market clearing functions are considered with no KKT optimality conditions. The derived function is solved using group search optimiser (GSO), a robust population-based optimisation algorithm. Experimental investigation is carried out on IEEE 14 as well as IEEE 30 bus systems and the performance is compared against differential evolution-based strategic bidding, genetic algorithm-based strategic bidding and particle swarm optimisation-based strategic bidding methods. The simulation results demonstrate that the obtained profit maximisation through GSO-based bidding strategies is higher than the other three methods.

  11. Climate change on the Colorado River: a method to search for robust management strategies

    Science.gov (United States)

    Keefe, R.; Fischbach, J. R.

    2010-12-01

    The Colorado River is a principal source of water for the seven Basin States, providing approximately 16.5 maf per year to users in the southwestern United States and Mexico. Though the dynamics of the river ensure Upper Basin users a reliable supply of water, the three Lower Basin states (California, Nevada, and Arizona) are in danger of delivery interruptions as Upper Basin demand increases and climate change threatens to reduce future streamflows. In light of the recent drought and uncertain effects of climate change on Colorado River flows, we evaluate the performance of a suite of policies modeled after the shortage sharing agreement adopted in December 2007 by the Department of the Interior. We build on the current literature by using a simplified model of the Lower Colorado River to consider future streamflow scenarios given climate change uncertainty. We also generate different scenarios of parametric consumptive use growth in the Upper Basin and evaluate alternate management strategies in light of these uncertainties. Uncertainty associated with climate change is represented with a multi-model ensemble from the literature, using a nearest neighbor perturbation to increase the size of the ensemble. We use Robust Decision Making to compare near-term or long-term management strategies across an ensemble of plausible future scenarios with the goal of identifying one or more approaches that are robust to alternate assumptions about the future. This method entails using search algorithms to quantitatively identify vulnerabilities that may threaten a given strategy (including the current operating policy) and characterize key tradeoffs between strategies under different scenarios.

  12. Searching for answers to clinical questions using google versus evidence-based summary resources: a randomized controlled crossover study.

    Science.gov (United States)

    Kim, Sarang; Noveck, Helaine; Galt, James; Hogshire, Lauren; Willett, Laura; O'Rourke, Kerry

    2014-06-01

    To compare the speed and accuracy of answering clinical questions using Google versus summary resources. In 2011 and 2012, 48 internal medicine interns from two classes at Rutgers University Robert Wood Johnson Medical School, who had been trained to use three evidence-based summary resources, performed four-minute computer searches to answer 10 clinical questions. Half were randomized to initiate searches for answers to questions 1 to 5 using Google; the other half initiated searches using a summary resource. They then crossed over and used the other resource for questions 6 to 10. They documented the time spent searching and the resource where the answer was found. Time to correct response and percentage of correct responses were compared between groups using t test and general estimating equations. Of 480 questions administered, interns found answers for 393 (82%). Interns initiating searches in Google used a wider variety of resources than those starting with summary resources. No significant difference was found in mean time to correct response (138.5 seconds for Google versus 136.1 seconds for summary resource; P = .72). Mean correct response rate was 58.4% for Google versus 61.5% for summary resource (mean difference -3.1%; 95% CI -10.3% to 4.2%; P = .40). The authors found no significant differences in speed or accuracy between searches initiated using Google versus summary resources. Although summary resources are considered to provide the highest quality of evidence, improvements to allow for better speed and accuracy are needed.

  13. Mate choice and the evolutionary stability of a fixed threshold in a sequential search strategy

    Directory of Open Access Journals (Sweden)

    Raymond Cheng

    2014-06-01

    Full Text Available The sequential search strategy is a prominent model of searcher behavior, derived as a rule by which females might sample and choose a mate from a distribution of prospective partners. The strategy involves a threshold criterion against which prospective mates are evaluated. The optimal threshold depends on the attributes of prospective mates, which are likely to vary across generations or within the lifetime of searchers due to stochastic environmental events. The extent of this variability and the cost to acquire information on the distribution of the quality of prospective mates determine whether a learned or environmentally canalized threshold is likely to be favored. In this paper, we determine conditions on cross-generational perturbations of the distribution of male phenotypes that allow for the evolutionary stability of an environmentally canalized threshold. In particular, we derive conditions under which there is a genetically determined threshold that is optimal over an evolutionary time scale in comparison to any other unlearned threshold. These considerations also reveal a simple algorithm by which the threshold could be learned.

  14. Relevant feature set estimation with a knock-out strategy and random forests

    DEFF Research Database (Denmark)

    Ganz, Melanie; Greve, Douglas N; Fischl, Bruce

    2015-01-01

    unintuitive and difficult to determine. In this article, we propose a novel MVPA method for group analysis of high-dimensional data that overcomes the drawbacks of the current techniques. Our approach explicitly aims to identify all relevant variations using a "knock-out" strategy and the Random Forest...

  15. Search strategies for Higgs Bosons at high energy e+e/sup /minus// colliders

    International Nuclear Information System (INIS)

    Alexander, J.; Burke, D.L.; Jung, C.K.; Komamiya, S.; Burchat, P.R.

    1989-01-01

    We have used detailed Monte Carlo simulations to study search strategies for Higgs bosons at high energy e + e/sup /minus// colliders. We extend an earlier study of the minimal single-Higgs-doublet model at a center-of-mass energy of 1 TeV to examine the effects of b-quark tagging and jet counting. It is found that these techniques can increase the signal-to-noise ratio substantially in the mass range around the W mass. In addition, we have studied this model at a center-of-mass energy of 400 GeV and found that an e + e/sup /minus// collider in this region would be sensitive to a Higgs boson with mass up to twice the Z/degree/ mass. We have also considered a nonminimal two-doublet model for the Higgs sector by extending a study of charged Higgs boson searches to include a mass very close to the mass of the W/sup +-/. We demonstrate that techniques which include b-quark tagging can be utilized to extract a significant signal. In addition, we have examined the prospects for detecting nonminimal neutral Higgs bosons at 1 TeV. We conclude that it would be possible to detect the CP-even and CP-odd neutral Higgs bosons when they are pair-produced in e + e/sup /minus// annihilation over a limited mass range. However, in some scenarios of supersymmetry, the charged Higgs boson constitutes a significant background to the CP-odd and the more massive CP-even neutral Higgs boson. 16 refs., 13 figs., 2 tabs

  16. Multiphasic on/off pheromone signalling in moths as neural correlates of a search strategy.

    Directory of Open Access Journals (Sweden)

    Dominique Martinez

    Full Text Available Insects and robots searching for odour sources in turbulent plumes face the same problem: the random nature of mixing causes fluctuations and intermittency in perception. Pheromone-tracking male moths appear to deal with discontinuous flows of information by surging upwind, upon sensing a pheromone patch, and casting crosswind, upon losing the plume. Using a combination of neurophysiological recordings, computational modelling and experiments with a cyborg, we propose a neuronal mechanism that promotes a behavioural switch between surge and casting. We show how multiphasic On/Off pheromone-sensitive neurons may guide action selection based on signalling presence or loss of the pheromone. A Hodgkin-Huxley-type neuron model with a small-conductance calcium-activated potassium (SK channel reproduces physiological On/Off responses. Using this model as a command neuron and the antennae of tethered moths as pheromone sensors, we demonstrate the efficiency of multiphasic patterning in driving a robotic searcher toward the source. Taken together, our results suggest that multiphasic On/Off responses may mediate olfactory navigation and that SK channels may account for these responses.

  17. Multiphasic on/off pheromone signalling in moths as neural correlates of a search strategy.

    Science.gov (United States)

    Martinez, Dominique; Chaffiol, Antoine; Voges, Nicole; Gu, Yuqiao; Anton, Sylvia; Rospars, Jean-Pierre; Lucas, Philippe

    2013-01-01

    Insects and robots searching for odour sources in turbulent plumes face the same problem: the random nature of mixing causes fluctuations and intermittency in perception. Pheromone-tracking male moths appear to deal with discontinuous flows of information by surging upwind, upon sensing a pheromone patch, and casting crosswind, upon losing the plume. Using a combination of neurophysiological recordings, computational modelling and experiments with a cyborg, we propose a neuronal mechanism that promotes a behavioural switch between surge and casting. We show how multiphasic On/Off pheromone-sensitive neurons may guide action selection based on signalling presence or loss of the pheromone. A Hodgkin-Huxley-type neuron model with a small-conductance calcium-activated potassium (SK) channel reproduces physiological On/Off responses. Using this model as a command neuron and the antennae of tethered moths as pheromone sensors, we demonstrate the efficiency of multiphasic patterning in driving a robotic searcher toward the source. Taken together, our results suggest that multiphasic On/Off responses may mediate olfactory navigation and that SK channels may account for these responses.

  18. NSGA-II Algorithm with a Local Search Strategy for Multiobjective Optimal Design of Dry-Type Air-Core Reactor

    Directory of Open Access Journals (Sweden)

    Chengfen Zhang

    2015-01-01

    Full Text Available Dry-type air-core reactor is now widely applied in electrical power distribution systems, for which the optimization design is a crucial issue. In the optimization design problem of dry-type air-core reactor, the objectives of minimizing the production cost and minimizing the operation cost are both important. In this paper, a multiobjective optimal model is established considering simultaneously the two objectives of minimizing the production cost and minimizing the operation cost. To solve the multi-objective optimization problem, a memetic evolutionary algorithm is proposed, which combines elitist nondominated sorting genetic algorithm version II (NSGA-II with a local search strategy based on the covariance matrix adaptation evolution strategy (CMA-ES. NSGA-II can provide decision maker with flexible choices among the different trade-off solutions, while the local-search strategy, which is applied to nondominated individuals randomly selected from the current population in a given generation and quantity, can accelerate the convergence speed. Furthermore, another modification is that an external archive is set in the proposed algorithm for increasing the evolutionary efficiency. The proposed algorithm is tested on a dry-type air-core reactor made of rectangular cross-section litz-wire. Simulation results show that the proposed algorithm has high efficiency and it converges to a better Pareto front.

  19. Large Neighborhood Search and Adaptive Randomized Decompositions for Flexible Jobshop Scheduling

    DEFF Research Database (Denmark)

    Pacino, Dario; Van Hentenryck, Pascal

    2011-01-01

    This paper considers a constraint-based scheduling approach to the flexible jobshop, a generalization of the traditional jobshop scheduling where activities have a choice of machines. It studies both large neighborhood (LNS) and adaptive randomized de- composition (ARD) schemes, using random...

  20. Similarity Digest Search: A Survey and Comparative Analysis of Strategies to Perform Known File Filtering Using Approximate Matching

    Directory of Open Access Journals (Sweden)

    Vitor Hugo Galhardo Moia

    2017-01-01

    Full Text Available Digital forensics is a branch of Computer Science aiming at investigating and analyzing electronic devices in the search for crime evidence. There are several ways to perform this search. Known File Filter (KFF is one of them, where a list of interest objects is used to reduce/separate data for analysis. Holding a database of hashes of such objects, the examiner performs lookups for matches against the target device. However, due to limitations over hash functions (inability to detect similar objects, new methods have been designed, called approximate matching. This sort of function has interesting characteristics for KFF investigations but suffers mainly from high costs when dealing with huge data sets, as the search is usually done by brute force. To mitigate this problem, strategies have been developed to better perform lookups. In this paper, we present the state of the art of similarity digest search strategies, along with a detailed comparison involving several aspects, as time complexity, memory requirement, and search precision. Our results show that none of the approaches address at least these main aspects. Finally, we discuss future directions and present requirements for a new strategy aiming to fulfill current limitations.

  1. Hiding and Searching Strategies of Adult Humans in a Virtual and a Real-Space Room

    Science.gov (United States)

    Talbot, Katherine J.; Legge, Eric L. G.; Bulitko, Vadim; Spetch, Marcia L.

    2009-01-01

    Adults searched for or cached three objects in nine hiding locations in a virtual room or a real-space room. In both rooms, the locations selected by participants differed systematically between searching and hiding. Specifically, participants moved farther from origin and dispersed their choices more when hiding objects than when searching for…

  2. A Content Analysis of Strategies and Tactics Observed among MLIS Students in an Online Searching Course

    Science.gov (United States)

    Ondrusek, Anita L.; Ren, Xiaoai; Yang, Changwoo

    2017-01-01

    Online searching is a skill that all professional programs educating librarians consider an essential part of their curricula. However, investigations of online searching behavior have centered almost exclusively on end users, and there have been no recent formal studies that explore the online searching behaviors of MLIS students. In this study,…

  3. Use of Cognitive and Metacognitive Strategies in Online Search: An Eye-Tracking Study

    Science.gov (United States)

    Zhou, Mingming; Ren, Jing

    2016-01-01

    This study used eye-tracking technology to track students' eye movements while searching information on the web. The research question guiding this study was "Do students with different search performance levels have different visual attention distributions while searching information online? If yes, what are the patterns for high and low…

  4. Preservation of biological information in thermal spring deposits - Developing a strategy for the search for fossil life on Mars

    Science.gov (United States)

    Walter, M. R.; Des Marais, David J.

    1993-01-01

    Paleobiological experience on earth is used here to develop a search strategy for fossil life on Mars. In particular, the exploration of thermal spring deposits is proposed as a way to maximize the chance of finding fossil life on Mars. As a basis for this suggestion, the characteristics of thermal springs are discussed in some detail.

  5. Integration of first-principles methods and crystallographic database searches for new ferroelectrics: Strategies and explorations

    International Nuclear Information System (INIS)

    Bennett, Joseph W.; Rabe, Karin M.

    2012-01-01

    In this concept paper, the development of strategies for the integration of first-principles methods with crystallographic database mining for the discovery and design of novel ferroelectric materials is discussed, drawing on the results and experience derived from exploratory investigations on three different systems: (1) the double perovskite Sr(Sb 1/2 Mn 1/2 )O 3 as a candidate semiconducting ferroelectric; (2) polar derivatives of schafarzikite MSb 2 O 4 ; and (3) ferroelectric semiconductors with formula M 2 P 2 (S,Se) 6 . A variety of avenues for further research and investigation are suggested, including automated structure type classification, low-symmetry improper ferroelectrics, and high-throughput first-principles searches for additional representatives of structural families with desirable functional properties. - Graphical abstract: Integration of first-principles methods with crystallographic database mining, for the discovery and design of novel ferroelectric materials, could potentially lead to new classes of multifunctional materials. Highlights: ► Integration of first-principles methods and database mining. ► Minor structural families with desirable functional properties. ► Survey of polar entries in the Inorganic Crystal Structural Database.

  6. Closing the Wedge: Search Strategies for Extended Higgs Sectors with Heavy Flavor Final States

    CERN Document Server

    Gori, Stefania; Shah, Nausheen R.; Zurek, Kathryn M.

    2016-01-01

    We consider search strategies for an extended Higgs sector at the high-luminosity LHC14 utilizing multi-top final states. In the framework of a Two Higgs Doublet Model, the purely top final states ($t\\bar t, \\, 4t$) are important channels for heavy Higgs bosons with masses in the wedge above $2\\,m_t$ and at low values of $\\tan\\beta$, while a $2 b 2t$ final state is most relevant at moderate values of $\\tan \\beta$. We find, in the $t\\bar t H$ channel, with $H \\rightarrow t \\bar t$, that both single and 3 lepton final states can provide statistically significant constraints at low values of $\\tan \\beta$ for $m_A$ as high as $\\sim 750$ GeV. When systematics on the $t \\bar t$ background are taken into account, however, the 3 lepton final state is more powerful, though the precise constraint depends fairly sensitively on lepton fake rates. We also find that neither $2b2t$ nor $t \\bar t$ final states provide constraints on additional heavy Higgs bosons with couplings to tops smaller than the top Yukawa due to expec...

  7. Prediction of shot success for basketball free throws: visual search strategy.

    Science.gov (United States)

    Uchida, Yusuke; Mizuguchi, Nobuaki; Honda, Masaaki; Kanosue, Kazuyuki

    2014-01-01

    In ball games, players have to pay close attention to visual information in order to predict the movements of both the opponents and the ball. Previous studies have indicated that players primarily utilise cues concerning the ball and opponents' body motion. The information acquired must be effective for observing players to select the subsequent action. The present study evaluated the effects of changes in the video replay speed on the spatial visual search strategy and ability to predict free throw success. We compared eye movements made while observing a basketball free throw by novices and experienced basketball players. Correct response rates were close to chance (50%) at all video speeds for the novices. The correct response rate of experienced players was significantly above chance (and significantly above that of the novices) at the normal speed, but was not different from chance at both slow and fast speeds. Experienced players gazed more on the lower part of the player's body when viewing a normal speed video than the novices. The players likely detected critical visual information to predict shot success by properly moving their gaze according to the shooter's movements. This pattern did not change when the video speed was decreased, but changed when it was increased. These findings suggest that temporal information is important for predicting action outcomes and that such outcomes are sensitive to video speed.

  8. Response Time, Visual Search Strategy, and Anticipatory Skills in Volleyball Players

    Directory of Open Access Journals (Sweden)

    Alessandro Piras

    2014-01-01

    Full Text Available This paper aimed at comparing expert and novice volleyball players in a visuomotor task using realistic stimuli. Videos of a volleyball setter performing offensive action were presented to participants, while their eye movements were recorded by a head-mounted video based eye tracker. Participants were asked to foresee the direction (forward or backward of the setter’s toss by pressing one of two keys. Key-press response time, response accuracy, and gaze behaviour were measured from the first frame showing the setter’s hand-ball contact to the button pressed by the participants. Experts were faster and more accurate in predicting the direction of the setting than novices, showing accurate predictions when they used a search strategy involving fewer fixations of longer duration, as well as spending less time in fixating all display areas from which they extract critical information for the judgment. These results are consistent with the view that superior performance in experts is due to their ability to efficiently encode domain-specific information that is relevant to the task.

  9. Power Stabilization Strategy of Random Access Loads in Electric Vehicles Wireless Charging System at Traffic Lights

    Directory of Open Access Journals (Sweden)

    Linlin Tan

    2016-10-01

    Full Text Available An opportunity wireless charging system for electric vehicles when they stop and wait at traffic lights is proposed in this paper. In order to solve the serious power fluctuation caused by random access loads, this study presents a power stabilization strategy based on counting the number of electric vehicles in a designated area, including counting method, power source voltage adjustment strategy and choice of counting points. Firstly, the circuit model of a wireless power system with multi-loads is built and the equation of each load is obtained. Secondly, after the counting method of electric vehicles is stated, the voltage adjustment strategy, based on the number of electric vehicles when the system is at a steady state, is set out. Then, the counting points are chosen according to power curves when the voltage adjustment strategy is adopted. Finally, an experimental prototype is implemented to verify the power stabilization strategy. The experimental results show that, with the application of this strategy, the charging power is stabilized with the fluctuation of no more than 5% when loads access randomly.

  10. Improvement of the Gravitational Search Algorithm by means of Low-Discrepancy Sobol Quasi Random-Number Sequence Based Initialization

    Directory of Open Access Journals (Sweden)

    ALTINOZ, O. T.

    2014-08-01

    Full Text Available Nature-inspired optimization algorithms can obtain the optima by updating the position of each member in the population. At the beginning of the algorithm, the particles of the population are spread into the search space. The initial distribution of particles corresponds to the beginning points of the search process. Hence, the aim is to alter the position for each particle beginning with this initial position until the optimum solution will be found with respect to the pre-determined conditions like maximum iteration, and specific error value for the fitness function. Therefore, initial positions of the population have a direct effect on both accuracy of the optima and the computational cost. If any member in the population is close enough to the optima, this eases the achievement of the exact solution. On the contrary, individuals grouped far away from the optima might yield pointless efforts. In this study, low-discrepancy quasi-random number sequence is preferred for the localization of the population at the initialization phase. By this way, the population is distributed into the search space in a more uniform manner at the initialization phase. The technique is applied to the Gravitational Search Algorithm and compared via the performance on benchmark function solutions.

  11. Operation management of daily economic dispatch using novel hybrid particle swarm optimization and gravitational search algorithm with hybrid mutation strategy

    Science.gov (United States)

    Wang, Yan; Huang, Song; Ji, Zhicheng

    2017-07-01

    This paper presents a hybrid particle swarm optimization and gravitational search algorithm based on hybrid mutation strategy (HGSAPSO-M) to optimize economic dispatch (ED) including distributed generations (DGs) considering market-based energy pricing. A daily ED model was formulated and a hybrid mutation strategy was adopted in HGSAPSO-M. The hybrid mutation strategy includes two mutation operators, chaotic mutation, Gaussian mutation. The proposed algorithm was tested on IEEE-33 bus and results show that the approach is effective for this problem.

  12. Strategies for prevention of postoperative delirium: a systematic review and meta-analysis of randomized trials

    Science.gov (United States)

    2013-01-01

    Introduction The ideal measures to prevent postoperative delirium remain unestablished. We conducted this systematic review and meta-analysis to clarify the significance of potential interventions. Methods The PRISMA statement guidelines were followed. Two researchers searched MEDLINE, EMBASE, CINAHL and the Cochrane Library for articles published in English before August 2012. Additional sources included reference lists from reviews and related articles from 'Google Scholar'. Randomized clinical trials (RCTs) on interventions seeking to prevent postoperative delirium in adult patients were included. Data extraction and methodological quality assessment were performed using predefined data fields and scoring system. Meta-analysis was accomplished for studies that used similar strategies. The primary outcome measure was the incidence of postoperative delirium. We further tested whether interventions effective in preventing postoperative delirium shortened the length of hospital stay. Results We identified 38 RCTs with interventions ranging from perioperative managements to pharmacological, psychological or multicomponent interventions. Meta-analysis showed dexmedetomidine sedation was associated with less delirium compared to sedation produced by other drugs (two RCTs with 415 patients, pooled risk ratio (RR) = 0.39; 95% confidence interval (CI) = 0.16 to 0.95). Both typical (three RCTs with 965 patients, RR = 0.71; 95% CI = 0.54 to 0.93) and atypical antipsychotics (three RCTs with 627 patients, RR = 0.36; 95% CI = 0.26 to 0.50) decreased delirium occurrence when compared to placebos. Multicomponent interventions (two RCTs with 325 patients, RR = 0.71; 95% CI = 0.58 to 0.86) were effective in preventing delirium. No difference in the incidences of delirium was found between: neuraxial and general anesthesia (four RCTs with 511 patients, RR = 0.99; 95% CI = 0.65 to 1.50); epidural and intravenous analgesia (three RCTs with 167 patients, RR = 0.93; 95% CI = 0.61 to 1

  13. Language-specific strategy for programming hearing aids - A double-blind randomized controlled crossover study.

    Science.gov (United States)

    Matsumoto, Nozomu; Suzuki, Nobuyoshi; Iwasaki, Satoshi; Ishikawa, Kazuha; Tsukiji, Hiroki; Higashino, Yoshie; Tabuki, Tomoko; Nakagawa, Takashi

    2018-08-01

    Voice-aligned compression (VAC) is a method used in Oticon's hearing aids to provide more comfortable hearing without sacrificing speech discrimination. The complex, non-linear compression curve for the VAC strategy is designed based on the frequency profile of certain spoken Western languages. We hypothesized that hearing aids could be further customized for Japanese-speaking users by modifying the compression curve using the frequency profile of spoken Japanese. A double-blind randomized controlled crossover study was performed to determine whether or not Oticon's modified amplification strategy (VAC-J) provides subjectively preferable hearing aids for Japanese-speaking hearing aid users compared to the same company's original amplification strategy (VAC). The participants were randomized to two groups. The VAC-first group received a pair of hearing aids programmed using the VAC strategy and wore them for three weeks, and then received a pair of hearing aids programmed using VAC-J strategy and wore them for three weeks. The VAC-J-first group underwent the same study, but they received hearing aids in the reverse sequence. A Speech, Spatial and Qualities (SSQ) questionnaire was administered before beginning to use the hearing aids, at the end of using the first pair of hearing aids, and at the end of using the second pair of hearing aids. Twenty-five participants that met the inclusion/exclusion criteria from January 1 to October 31, 2016, were randomized to two groups. Twenty-two participants completed the study. There were no statistically significant differences in the increment of SSQ scores between the participants when using the VAC- or the VAC-J-programmed hearing aids. However, participants preferred the VAC-J strategy to the VAC strategy at the end of the study, and this difference was statistically significant. Japanese-speaking hearing aid users preferred using hearing aids that were fitted with the VAC-J strategy. Our results show that the VAC strategy

  14. A Search Strategy of Level-Based Flooding for the Internet of Things

    Science.gov (United States)

    Qiu, Tie; Ding, Yanhong; Xia, Feng; Ma, Honglian

    2012-01-01

    This paper deals with the query problem in the Internet of Things (IoT). Flooding is an important query strategy. However, original flooding is prone to cause heavy network loads. To address this problem, we propose a variant of flooding, called Level-Based Flooding (LBF). With LBF, the whole network is divided into several levels according to the distances (i.e., hops) between the sensor nodes and the sink node. The sink node knows the level information of each node. Query packets are broadcast in the network according to the levels of nodes. Upon receiving a query packet, sensor nodes decide how to process it according to the percentage of neighbors that have processed it. When the target node receives the query packet, it sends its data back to the sink node via random walk. We show by extensive simulations that the performance of LBF in terms of cost and latency is much better than that of original flooding, and LBF can be used in IoT of different scales. PMID:23112594

  15. Comparing three knowledge communication strategies - Diffusion, Dissemination and Translation - through randomized controlled studies.

    Science.gov (United States)

    Lane, Joseph P; Stone, Vathsala I

    2015-01-01

    This paper describes a series of three randomized controlled case studies comparing the effectiveness of three strategies for communicating new research-based knowledge (Diffusion, Dissemination, Translation), to different Assistive Technology (AT) stakeholder groups. Pre and post intervention measures for level of knowledge use (unaware, aware, interested, using) via the LOKUS instrument, assessed the relative effectiveness of the three strategies. The latter two approaches were both more effective than diffusion but also equally effective. The results question the value added by tailoring research findings to specific audiences, and instead supports the critical yet neglected role for relevance in determining knowledge use by stakeholders.

  16. Randomized dynamical decoupling strategies and improved one-way key rates for quantum cryptography

    Energy Technology Data Exchange (ETDEWEB)

    Kern, Oliver

    2009-05-25

    The present thesis deals with various methods of quantum error correction. It is divided into two parts. In the first part, dynamical decoupling methods are considered which have the task of suppressing the influence of residual imperfections in a quantum memory. Such imperfections might be given by couplings between the finite dimensional quantum systems (qudits) constituting the quantum memory, for instance. The suppression is achieved by altering the dynamics of an imperfect quantum memory with the help of a sequence of local unitary operations applied to the qudits. Whereas up to now the operations of such decoupling sequences have been constructed in a deterministic fashion, strategies are developed in this thesis which construct the operations by random selection from a suitable set. Formulas are derived which estimate the average performance of such strategies. As it turns out, randomized decoupling strategies offer advantages and disadvantages over deterministic ones. It is possible to benefit from the advantages of both kind of strategies by designing combined strategies. Furthermore, it is investigated if and how the discussed decoupling strategies can be employed to protect a quantum computation running on the quantum memory. It is shown that a purely randomized decoupling strategy may be used by applying the decoupling operations and adjusted gates of the quantum algorithm in an alternating fashion. Again this method can be enhanced by the means of deterministic methods in order to obtain a combined decoupling method for quantum computations analogously to the combining strategies for quantum memories. The second part of the thesis deals with quantum error-correcting codes and protocols for quantum key distribution. The focus is on the BB84 and the 6-state protocol making use of only one-way communication during the error correction and privacy amplification steps. It is shown that by adding additional errors to the preliminary key (a process called

  17. Randomized dynamical decoupling strategies and improved one-way key rates for quantum cryptography

    International Nuclear Information System (INIS)

    Kern, Oliver

    2009-01-01

    The present thesis deals with various methods of quantum error correction. It is divided into two parts. In the first part, dynamical decoupling methods are considered which have the task of suppressing the influence of residual imperfections in a quantum memory. Such imperfections might be given by couplings between the finite dimensional quantum systems (qudits) constituting the quantum memory, for instance. The suppression is achieved by altering the dynamics of an imperfect quantum memory with the help of a sequence of local unitary operations applied to the qudits. Whereas up to now the operations of such decoupling sequences have been constructed in a deterministic fashion, strategies are developed in this thesis which construct the operations by random selection from a suitable set. Formulas are derived which estimate the average performance of such strategies. As it turns out, randomized decoupling strategies offer advantages and disadvantages over deterministic ones. It is possible to benefit from the advantages of both kind of strategies by designing combined strategies. Furthermore, it is investigated if and how the discussed decoupling strategies can be employed to protect a quantum computation running on the quantum memory. It is shown that a purely randomized decoupling strategy may be used by applying the decoupling operations and adjusted gates of the quantum algorithm in an alternating fashion. Again this method can be enhanced by the means of deterministic methods in order to obtain a combined decoupling method for quantum computations analogously to the combining strategies for quantum memories. The second part of the thesis deals with quantum error-correcting codes and protocols for quantum key distribution. The focus is on the BB84 and the 6-state protocol making use of only one-way communication during the error correction and privacy amplification steps. It is shown that by adding additional errors to the preliminary key (a process called

  18. The Search for Suitable Strategy: Threat-Based and Capabilities-Based Strategies in a Complex World

    Science.gov (United States)

    2016-05-26

    the 1973 Arab-Israeli War show that the true path to suitable strategy is a measure of forethought and theoretical planning exercises to shape habits ...is a measure of forethought and theoretical planning exercises to shape habits of thought and identify risks or shortcomings inherent in a chosen...political direction to the military instrument of power , while military strategy links military means to those 22 Oxford Dictionaries, s.v. “Strategy

  19. Protein-Level Integration Strategy of Multiengine MS Spectra Search Results for Higher Confidence and Sequence Coverage.

    Science.gov (United States)

    Zhao, Panpan; Zhong, Jiayong; Liu, Wanting; Zhao, Jing; Zhang, Gong

    2017-12-01

    Multiple search engines based on various models have been developed to search MS/MS spectra against a reference database, providing different results for the same data set. How to integrate these results efficiently with minimal compromise on false discoveries is an open question due to the lack of an independent, reliable, and highly sensitive standard. We took the advantage of the translating mRNA sequencing (RNC-seq) result as a standard to evaluate the integration strategies of the protein identifications from various search engines. We used seven mainstream search engines (Andromeda, Mascot, OMSSA, X!Tandem, pFind, InsPecT, and ProVerB) to search the same label-free MS data sets of human cell lines Hep3B, MHCCLM3, and MHCC97H from the Chinese C-HPP Consortium for Chromosomes 1, 8, and 20. As expected, the union of seven engines resulted in a boosted false identification, whereas the intersection of seven engines remarkably decreased the identification power. We found that identifications of at least two out of seven engines resulted in maximizing the protein identification power while minimizing the ratio of suspicious/translation-supported identifications (STR), as monitored by our STR index, based on RNC-Seq. Furthermore, this strategy also significantly improves the peptides coverage of the protein amino acid sequence. In summary, we demonstrated a simple strategy to significantly improve the performance for shotgun mass spectrometry by protein-level integrating multiple search engines, maximizing the utilization of the current MS spectra without additional experimental work.

  20. GRASP (Greedy Randomized Adaptive Search Procedures) applied to optimization of petroleum products distribution in pipeline networks; GRASP (Greedy Randomized Adaptative Search Procedures) aplicado ao 'scheduling' de redes de distribuicao de petroleo e derivados

    Energy Technology Data Exchange (ETDEWEB)

    Conte, Viviane Cristhyne Bini; Arruda, Lucia Valeria Ramos de; Yamamoto, Lia [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil)

    2008-07-01

    Planning and scheduling of the pipeline network operations aim the most efficient use of the resources resulting in a better performance of the network. A petroleum distribution pipeline network is composed by refineries, sources and/or storage parks, connected by a set of pipelines, which operate the transportation of petroleum and derivatives among adjacent areas. In real scenes, this problem is considered a combinatorial problem, which has difficult solution, which makes necessary methodologies of the resolution that present low computational time. This work aims to get solutions that attempt the demands and minimize the number of batch fragmentations on the sent operations of products for the pipelines in a simplified model of a real network, through by application of the local search metaheuristic GRASP. GRASP does not depend of solutions of previous iterations and works in a random way so it allows the search for the solution in an ampler and diversified search space. GRASP utilization does not demand complex calculation, even the construction stage that requires more computational effort, which provides relative rapidity in the attainment of good solutions. GRASP application on the scheduling of the operations of this network presented feasible solutions in a low computational time. (author)

  1. In Search of Meaning: Are School Rampage Shootings Random and Senseless Violence?

    Science.gov (United States)

    Madfis, Eric

    2017-01-02

    This article discusses Joel Best's ( 1999 ) notion of random violence and applies his concepts of pointlessness, patternlessness, and deterioration to the reality about multiple-victim school shootings gleaned from empirical research about the phenomenon. Best describes how violence is rarely random, as scholarship reveals myriad observable patterns, lots of discernable motives and causes, and often far too much fear-mongering over how bad society is getting and how violent we are becoming. In contrast, it is vital that the media, scholars, and the public better understand crime patterns, criminal motivations, and the causes of fluctuating crime rates. As an effort toward such progress, this article reviews the academic literature on school rampage shootings and explores the extent to which these attacks are and are not random acts of violence.

  2. Search on a hypercubic lattice using a quantum random walk. II. d=2

    International Nuclear Information System (INIS)

    Patel, Apoorva; Raghunathan, K. S.; Rahaman, Md. Aminoor

    2010-01-01

    We investigate the spatial search problem on the two-dimensional square lattice, using the Dirac evolution operator discretized according to the staggered lattice fermion formalism. d=2 is the critical dimension for the spatial search problem, where infrared divergence of the evolution operator leads to logarithmic factors in the scaling behavior. As a result, the construction used in our accompanying article [A. Patel and M. A. Rahaman, Phys. Rev. A 82, 032330 (2010)] provides an O(√(N)lnN) algorithm, which is not optimal. The scaling behavior can be improved to O(√(NlnN)) by cleverly controlling the massless Dirac evolution operator by an ancilla qubit, as proposed by Tulsi [Phys. Rev. A 78, 012310 (2008)]. We reinterpret the ancilla control as introduction of an effective mass at the marked vertex, and optimize the proportionality constants of the scaling behavior of the algorithm by numerically tuning the parameters.

  3. Three-dimensional high-precision indoor positioning strategy using Tabu search based on visible light communication

    Science.gov (United States)

    Peng, Qi; Guan, Weipeng; Wu, Yuxiang; Cai, Ye; Xie, Canyu; Wang, Pengfei

    2018-01-01

    This paper proposes a three-dimensional (3-D) high-precision indoor positioning strategy using Tabu search based on visible light communication. Tabu search is a powerful global optimization algorithm, and the 3-D indoor positioning can be transformed into an optimal solution problem. Therefore, in the 3-D indoor positioning, the optimal receiver coordinate can be obtained by the Tabu search algorithm. For all we know, this is the first time the Tabu search algorithm is applied to visible light positioning. Each light-emitting diode (LED) in the system broadcasts a unique identity (ID) and transmits the ID information. When the receiver detects optical signals with ID information from different LEDs, using the global optimization of the Tabu search algorithm, the 3-D high-precision indoor positioning can be realized when the fitness value meets certain conditions. Simulation results show that the average positioning error is 0.79 cm, and the maximum error is 5.88 cm. The extended experiment of trajectory tracking also shows that 95.05% positioning errors are below 1.428 cm. It can be concluded from the data that the 3-D indoor positioning based on the Tabu search algorithm achieves the requirements of centimeter level indoor positioning. The algorithm used in indoor positioning is very effective and practical and is superior to other existing methods for visible light indoor positioning.

  4. Searching for control: priming randomness increases the evaluation of ritual efficacy.

    Science.gov (United States)

    Legare, Cristine H; Souza, André L

    2014-01-01

    Reestablishing feelings of control after experiencing uncertainty has long been considered a fundamental motive for human behavior. We propose that rituals (i.e., socially stipulated, causally opaque practices) provide a means for coping with the aversive feelings associated with randomness due to the perception of a connection between ritual action and a desired outcome. Two experiments were conducted (one in Brazil [n = 40] and another in the United States [n = 94]) to evaluate how the perceived efficacy of rituals is affected by feelings of randomness. In a between-subjects design, the Scramble Sentence Task was used as a priming procedure in three conditions (i.e., randomness, negativity, and neutral) and participants were then asked to rate the efficacy of rituals used for problem-solving purposes. The results demonstrate that priming randomness increased participants' perception of ritual efficacy relative to negativity and neutral conditions. Implications for increasing our understanding of the relationship between perceived control and ritualistic behavior are discussed. Copyright © 2013 Cognitive Science Society, Inc.

  5. Fitness landscapes, heuristics and technological paradigms: a critique on random search models in evolutionary economics

    NARCIS (Netherlands)

    Frenken, K.

    2001-01-01

    The biological evolution of complex organisms, in which the functioning of genes is interdependent, has been analyzed as "hill-climbing" on NK fitness landscapes through random mutation and natural selection. In evolutionary economics, NK fitness landscapes have been used to simulate the evolution

  6. New Search Strategies Successfully Optimize Retrieval of Clinically Sound Treatment Studies in EMBASE. A review of: Wong, Sharon S‐L, Nancy L. Wilczynski, and R. Brian Haynes. “Developing Optimal Search Strategies for Detecting Clinically Sound Treatment Studies in EMBASE.” Journal of the Medical Library Association 94.1 (Jan. 2006: 41‐47. 14 May 2007 http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1324770.

    Directory of Open Access Journals (Sweden)

    John Loy

    2007-06-01

    Full Text Available Objective – To develop and test the sensitivity and specificity, precision andaccuracy of search strategies to retrieve clinically sound treatment studies in the EMBASE database.Design – Analytical study.Setting – Methodologically sound studies of treatment from 55 journals indexed in EMBASE for the year 2000.Subjects – EMBASE and hand searches performed at the Health Information Research Unit of McMaster University, Ontario, Canada.Methods – The authors compare the results of EMBASE searches using their search strategies with the “gold standard” of articles retrieved by hand search. Research assistants initially hand searched each issue of 55 selected journals published in 2000 to identify articles detailing studies on healthcare treatment of humans. Subject coverage of the journals was wide ranging and included obstetrics and gynaecology, psychiatry, oncology, neurology, surgery and general practice. Studies were then assessed to ensure they met the qualifying criteria: random allocation of participants to groups, outcome assessment of at least 80% of participants who began the study, and analysis consistent with study design. Initially, 3850 articles on treatment were identified, of which 1256 (32.6% were methodologically sound. To construct a comprehensive set of search terms, input was sought from librarians and researchers in the US and Canada. This initially produced a list of 5385 terms, of which 4843 were unique and 3524 produced hits. Individual search terms with sensitivity greater then 25% and specificity greater then 75% were incorporated into search strategies for use within the OVID interface for the EMBASE database to retrieve articles meeting the same criteria. These strategies were developed using all 27,769 articles published in the 55 journals in 2000. This all inclusive approach was used to test the search strategies’ ability to identify high quality treatment articles from a larger pool of material

  7. Search strategies to identify diagnostic accuracy studies in MEDLINE and EMBASE

    NARCIS (Netherlands)

    Beynon, Rebecca; Leeflang, Mariska M. G.; McDonald, Steve; Eisinga, Anne; Mitchell, Ruth L.; Whiting, Penny; Glanville, Julie M.

    2013-01-01

    A systematic and extensive search for as many eligible studies as possible is essential in any systematic review. When searching for diagnostic test accuracy (DTA) studies in bibliographic databases, it is recommended that terms for disease (target condition) are combined with terms for the

  8. More than Just Finding Color: Strategy in Global Visual Search Is Shaped by Learned Target Probabilities

    Science.gov (United States)

    Williams, Carrick C.; Pollatsek, Alexander; Cave, Kyle R.; Stroud, Michael J.

    2009-01-01

    In 2 experiments, eye movements were examined during searches in which elements were grouped into four 9-item clusters. The target (a red or blue "T") was known in advance, and each cluster contained different numbers of target-color elements. Rather than color composition of a cluster invariantly guiding the order of search though…

  9. Search Strategy Development in a Flipped Library Classroom: A Student-Focused Assessment

    Science.gov (United States)

    Goates, Michael C.; Nelson, Gregory M.; Frost, Megan

    2017-01-01

    Librarians at Brigham Young University compared search statement development between traditional lecture and flipped instruction sessions. Students in lecture sessions scored significantly higher on developing search statements than those in flipped sessions. However, student evaluations show a strong preference for pedagogies that incorporate…

  10. Blackout risk prevention in a smart grid based flexible optimal strategy using Grey Wolf-pattern search algorithms

    International Nuclear Information System (INIS)

    Mahdad, Belkacem; Srairi, K.

    2015-01-01

    Highlights: • A generalized optimal security power system planning strategy for blackout risk prevention is proposed. • A Grey Wolf Optimizer dynamically coordinated with Pattern Search algorithm is proposed. • A useful optimized database dynamically generated considering margin loading stability under severe faults. • The robustness and feasibility of the proposed strategy is validated in the standard IEEE 30 Bus system. • The proposed planning strategy will be useful for power system protection coordination and control. - Abstract: Developing a flexible and reliable power system planning strategy under critical situations is of great importance to experts and industrials to minimize the probability of blackouts occurrence. This paper introduces the first stage of this practical strategy by the application of Grey Wolf Optimizer coordinated with pattern search algorithm for solving the security smart grid power system management under critical situations. The main objective of this proposed planning strategy is to prevent the practical power system against blackout due to the apparition of faults in generating units or important transmission lines. At the first stage the system is pushed to its margin stability limit, the critical loads shedding are selected using voltage stability index. In the second stage the generator control variables, the reactive power of shunt and dynamic compensators are adjusted in coordination with minimization the active and reactive power at critical loads to maintain the system at security state to ensure service continuity. The feasibility and efficiency of the proposed strategy is applied to IEEE 30-Bus test system. Results are promising and prove the practical efficiency of the proposed strategy to ensure system security under critical situations

  11. Managing search strategies for open innovation : the role of environmental munificence as well as internal and external R&D

    OpenAIRE

    Sofka, Wolfgang; Grimpe, Christoph

    2008-01-01

    Firms compete increasingly in an open innovation environment. Search strategies for external knowledge become therefore crucial for firm success. Existing research differentiates between the breadth (diversity) and depth (intensity) with which firms pursue external knowledge source. A consensus exists that resource constrains force firms to balance both dimensions. However, relatively little is known on how managers can selectively strengthen one of these dimensions. We argue conceptually tha...

  12. School-based strategies for oral health education of adolescents- a cluster randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Haleem Abdul

    2012-12-01

    Full Text Available Abstract Background Oral health education (OHE in schools has largely been imparted by dental professionals. Considering the substantial cost of this expert-led approach, the strategies relying on teachers, peer-leaders and learners themselves have also been utilized. However the evidence for comparative effectiveness of these strategies is lacking in the dental literature. The present study was conducted to compare the effectiveness of dentist-led, teacher-led, peer-led and self-learning strategies of oral health education. Methods A two-year cluster randomized controlled trial following a parallel design was conducted. It involved five groups of adolescents aged 10-11 years at the start of the study. The trial involved process as well as four outcome evaluations. The present paper discusses the findings of the study pertaining to the baseline and final outcome evaluation, both comprising of a self-administered questionnaire, a structured interview and clinical oral examination. The data were analyzed using Generalized Estimating Equations. Results All the three educator-led strategies of OHE had statistically higher mean oral health knowledge (OHK, oral health behavior (OHB, oral hygiene status (OHS and combined knowledge, behavior and oral hygiene status (KBS scores than the self-learning and control groups (p Conclusions The dentist-led, teacher-led and peer-led strategies of oral health education are equally effective in improving the oral health knowledge and oral hygiene status of adolescents. The peer-led strategy, however, is almost as effective as the dentist-led strategy and comparatively more effective than the teacher-led and self-learning strategies in improving their oral health behavior. Trail registration SRCTN39391017

  13. A highly sensitive search strategy for clinical trials in Literatura Latino Americana e do Caribe em Ciências da Saúde (LILACS) was developed.

    Science.gov (United States)

    Manríquez, Juan J

    2008-04-01

    Systematic reviews should include as many articles as possible. However, many systematic reviews use only databases with high English language content as sources of trials. Literatura Latino Americana e do Caribe em Ciências da Saúde (LILACS) is an underused source of trials, and there is not a validated strategy for searching clinical trials to be used in this database. The objective of this study was to develop a sensitive search strategy for clinical trials in LILACS. An analytical survey was performed. Several single and multiple-term search strategies were tested for their ability to retrieve clinical trials in LILACS. Sensitivity, specificity, and accuracy of each single and multiple-term strategy were calculated using the results of a hand-search of 44 Chilean journals as gold standard. After combining the most sensitive, specific, and accurate single and multiple-term search strategy, a strategy with a sensitivity of 97.75% (95% confidence interval [CI]=95.98-99.53) and a specificity of 61.85 (95% CI=61.19-62.51) was obtained. LILACS is a source of trials that could improve systematic reviews. A new highly sensitive search strategy for clinical trials in LILACS has been developed. It is hoped this search strategy will improve and increase the utilization of LILACS in future systematic reviews.

  14. the Ĝ infrared search for extraterrestrial civilizations with large energy supplies. II. Framework, strategy, and first result

    Energy Technology Data Exchange (ETDEWEB)

    Wright, J. T.; Griffith, R. L.; Sigurdsson, S. [Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA, 16802 (United States); Povich, M. S. [Department of Physics and Astronomy, California State Polytechnic University, Pomona, 3801 West Temple Avenue, Pomona, CA 91768 (United States); Mullan, B. [Blue Marble Space Institution of Science, P.O. Box 85561, Seattle, WA 98145-1561 (United States)

    2014-09-01

    We describe the framework and strategy of the Ĝ infrared search for extraterrestrial civilizations with large energy supplies, which will use the wide-field infrared surveys of WISE and Spitzer to search for these civilizations' waste heat. We develop a formalism for translating mid-infrared photometry into quantitative upper limits on extraterrestrial energy supplies. We discuss the likely sources of false positives, how dust can and will contaminate our search, and prospects for distinguishing dust from alien waste heat. We argue that galaxy-spanning civilizations may be easier to distinguish from natural sources than circumstellar civilizations (i.e., Dyson spheres), although GAIA will significantly improve our capability to identify the latter. We present a zeroth order null result of our search based on the WISE all-sky catalog: we show, for the first time, that Kardashev Type III civilizations (as Kardashev originally defined them) are very rare in the local universe. More sophisticated searches can extend our methodology to smaller waste heat luminosities, and potentially entirely rule out (or detect) both Kardashev Type III civilizations and new physics that allows for unlimited 'free' energy generation.

  15. the Ĝ infrared search for extraterrestrial civilizations with large energy supplies. II. Framework, strategy, and first result

    International Nuclear Information System (INIS)

    Wright, J. T.; Griffith, R. L.; Sigurdsson, S.; Povich, M. S.; Mullan, B.

    2014-01-01

    We describe the framework and strategy of the Ĝ infrared search for extraterrestrial civilizations with large energy supplies, which will use the wide-field infrared surveys of WISE and Spitzer to search for these civilizations' waste heat. We develop a formalism for translating mid-infrared photometry into quantitative upper limits on extraterrestrial energy supplies. We discuss the likely sources of false positives, how dust can and will contaminate our search, and prospects for distinguishing dust from alien waste heat. We argue that galaxy-spanning civilizations may be easier to distinguish from natural sources than circumstellar civilizations (i.e., Dyson spheres), although GAIA will significantly improve our capability to identify the latter. We present a zeroth order null result of our search based on the WISE all-sky catalog: we show, for the first time, that Kardashev Type III civilizations (as Kardashev originally defined them) are very rare in the local universe. More sophisticated searches can extend our methodology to smaller waste heat luminosities, and potentially entirely rule out (or detect) both Kardashev Type III civilizations and new physics that allows for unlimited 'free' energy generation.

  16. The Ĝ Infrared Search for Extraterrestrial Civilizations with Large Energy Supplies. II. Framework, Strategy, and First Result

    Science.gov (United States)

    Wright, J. T.; Griffith, R. L.; Sigurdsson, S.; Povich, M. S.; Mullan, B.

    2014-09-01

    We describe the framework and strategy of the Ĝ infrared search for extraterrestrial civilizations with large energy supplies, which will use the wide-field infrared surveys of WISE and Spitzer to search for these civilizations' waste heat. We develop a formalism for translating mid-infrared photometry into quantitative upper limits on extraterrestrial energy supplies. We discuss the likely sources of false positives, how dust can and will contaminate our search, and prospects for distinguishing dust from alien waste heat. We argue that galaxy-spanning civilizations may be easier to distinguish from natural sources than circumstellar civilizations (i.e., Dyson spheres), although GAIA will significantly improve our capability to identify the latter. We present a zeroth order null result of our search based on the WISE all-sky catalog: we show, for the first time, that Kardashev Type III civilizations (as Kardashev originally defined them) are very rare in the local universe. More sophisticated searches can extend our methodology to smaller waste heat luminosities, and potentially entirely rule out (or detect) both Kardashev Type III civilizations and new physics that allows for unlimited "free" energy generation.

  17. Protocol: a systematic review of studies developing and/or evaluating search strategies to identify prognosis studies.

    Science.gov (United States)

    Corp, Nadia; Jordan, Joanne L; Hayden, Jill A; Irvin, Emma; Parker, Robin; Smith, Andrea; van der Windt, Danielle A

    2017-04-20

    Prognosis research is on the rise, its importance recognised because chronic health conditions and diseases are increasingly common and costly. Prognosis systematic reviews are needed to collate and synthesise these research findings, especially to help inform effective clinical decision-making and healthcare policy. A detailed, comprehensive search strategy is central to any systematic review. However, within prognosis research, this is challenging due to poor reporting and inconsistent use of available indexing terms in electronic databases. Whilst many published search filters exist for finding clinical trials, this is not the case for prognosis studies. This systematic review aims to identify and compare existing methodological filters developed and evaluated to identify prognosis studies of any of the three main types: overall prognosis, prognostic factors, and prognostic [risk prediction] models. Primary studies reporting the development and/or evaluation of methodological search filters to retrieve any type of prognosis study will be included in this systematic review. Multiple electronic bibliographic databases will be searched, grey literature will be sought from relevant organisations and websites, experts will be contacted, and citation tracking of key papers and reference list checking of all included papers will be undertaken. Titles will be screened by one person, and abstracts and full articles will be reviewed for inclusion independently by two reviewers. Data extraction and quality assessment will also be undertaken independently by two reviewers with disagreements resolved by discussion or by a third reviewer if necessary. Filters' characteristics and performance metrics reported in the included studies will be extracted and tabulated. To enable comparisons, filters will be grouped according to database, platform, type of prognosis study, and type of filter for which it was intended. This systematic review will identify all existing validated

  18. Penerapan Teknik Seo (Search Engine Optimization pada Website dalam Strategi Pemasaran melalui Internet

    Directory of Open Access Journals (Sweden)

    Rony Baskoro Lukito

    2014-12-01

    Full Text Available The purpose of this research is how to optimize a web design that can increase the number of visitors. The number of Internet users in the world continues to grow in line with advances in information technology. Products and services marketing media do not just use the printed and electronic media. Moreover, the cost of using the Internet as a medium of marketing is relatively inexpensive when compared to the use of television as a marketing medium. The penetration of the internet as a marketing medium lasted for 24 hours in different parts of the world. But to make an internet site into a site that is visited by many internet users, the site is not only good from the outside view only. Web sites that serve as a medium for marketing must be built with the correct rules, so that the Web site be optimal marketing media. One of the good rules in building the internet site as a marketing medium is how the content of such web sites indexed well in search engines like google. Search engine optimization in the index will be focused on the search engine Google for 83% of internet users across the world using Google as a search engine. Search engine optimization commonly known as SEO (Search Engine Optimization is an important rule that the internet site is easier to find a user with the desired keywords.

  19. Restrictive versus liberal transfusion strategies for older mechanically ventilated critically ill patients: a randomized pilot trial.

    Science.gov (United States)

    Walsh, Timothy S; Boyd, Julia A; Watson, Douglas; Hope, David; Lewis, Steff; Krishan, Ashma; Forbes, John F; Ramsay, Pamela; Pearse, Rupert; Wallis, Charles; Cairns, Christopher; Cole, Stephen; Wyncoll, Duncan

    2013-10-01

    To compare hemoglobin concentration (Hb), RBC use, and patient outcomes when restrictive or liberal blood transfusion strategies are used to treat anemic (Hb≤90 g/L) critically ill patients of age≥55 years requiring≥4 days of mechanical ventilation in ICU. Parallel-group randomized multicenter pilot trial. Six ICUs in the United Kingdom participated between August 2009 and December 2010. One hundred patients (51 restrictive and 49 liberal groups). Patients were randomized to a restrictive (Hb trigger, 70 g/L; target, 71-90 g/L) or liberal (90 g/L; target, 91-110 g/L) transfusion strategy for 14 days or the remainder of ICU stay, whichever was longest. Baseline comorbidity rates and illness severity were high, notably for ischemic heart disease (32%). The Hb difference among groups was 13.8 g/L (95% CI, 11.5-16.0 g/L); pdisease, Acute Physiology and Chronic Health Evaluation II score, and total non-neurologic Sequential Organ Failure Assessment score at baseline (hazard ratio, 0.54 [95% CI, 0.28-1.03]; p=0.061). A large trial of transfusion strategies in older mechanically ventilated patients is feasible. This pilot trial found a nonsignificant trend toward lower mortality with restrictive transfusion practice.

  20. Honeybees (Apis mellifera exhibit flexible visual search strategies for vertical targets presented at various heights [v2; ref status: indexed, http://f1000r.es/51p

    Directory of Open Access Journals (Sweden)

    Linde Morawetz

    2015-02-01

    Full Text Available When honeybees are presented with a colour discrimination task, they tend to choose swiftly and accurately when objects are presented in the ventral part of their frontal visual field. In contrast, poor performance is observed when objects appear in the dorsal part. Here we investigate if this asymmetry is caused by fixed search patterns or if bees can increase their detection ability of objects in search scenarios when targets appear frequently or exclusively in the dorsal area of the visual field. We trained individual honeybees to choose an orange rewarded target among blue distractors. Target and distractors were presented in the ventral visual field, the dorsal field or both. Bees presented with targets in the ventral visual field consistently had the highest search efficiency, with rapid decisions, high accuracy and direct flight paths. In contrast, search performance for dorsally located targets was inaccurate and slow at the beginning of the experimental phase, but bees increased their search performance significantly after a few foraging bouts: they found the target faster, made fewer errors and flew in a straight line towards the target. However, bees needed thrice as long to improve the search for a dorsally located target when the target’s position changed randomly between the ventral and the dorsal visual field. We propose that honeybees form expectations of the location of the target’s appearance and adapt their search strategy accordingly. A variety of possible mechanisms underlying this behavioural adaptation, for example spatial attention, are discussed.

  1. Strategies to improve recruitment and retention of older stroke survivors to a randomized clinical exercise trial.

    Science.gov (United States)

    Taylor-Piliae, Ruth E; Boros, Daniella; Coull, Bruce M

    2014-03-01

    Relatively few exercise randomized clinical trials (RCTs) among stroke survivors have reported the effectiveness of recruitment and retention strategies, despite its central importance to study integrity. Our objective is to examine recruitment and retention strategies used among a group of older community-dwelling stroke survivors for an exercise RCT. Recruitment strategies were multidimensional using both paid (ie, newspaper, radio and, television) and unpaid advertisements (ie, staff visits, flyers, and brochures placed at outpatient rehabilitation centers, physician offices, and community facilities working with older adults; free media coverage of the study, presentations at stroke support groups, relatives/friends, and study Web site) to obtain referrals. Retention strategies centered on excellent communication, the study participants' needs, and having dedicated study staff. Attrition rates and adherence to the intervention were used to examine the effectiveness of these retention strategies. A total of 393 referrals were received, 233 persons were screened, and 145 stroke survivors enrolled in the study. During 3 years of study recruitment, we achieved 97% of our enrollment target. We enrolled 62% of those screened. Study enrollment from paid advertising was 21.4% (n = 31), whereas unpaid advertisements resulted in 78.6% (n = 114) of our participants. Attrition was 10% (n = 14 dropouts), and adherence to the intervention was 85%. Recruitment and retention of participants in an exercise RCT are time and labor intensive. Multiple recruitment and retention strategies are required to ensure an adequate sample of community-dwelling stroke survivors. Many of these strategies are also relevant for exercise RCTs among adults with other chronic illnesses. Copyright © 2014 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  2. Evolving cellular automata for diversity generation and pattern recognition: deterministic versus random strategy

    International Nuclear Information System (INIS)

    De Menezes, Marcio Argollo; Brigatti, Edgardo; Schwämmle, Veit

    2013-01-01

    Microbiological systems evolve to fulfil their tasks with maximal efficiency. The immune system is a remarkable example, where the distinction between self and non-self is made by means of molecular interaction between self-proteins and antigens, triggering affinity-dependent systemic actions. Specificity of this binding and the infinitude of potential antigenic patterns call for novel mechanisms to generate antibody diversity. Inspired by this problem, we develop a genetic algorithm where agents evolve their strings in the presence of random antigenic strings and reproduce with affinity-dependent rates. We ask what is the best strategy to generate diversity if agents can rearrange their strings a finite number of times. We find that endowing each agent with an inheritable cellular automaton rule for performing rearrangements makes the system more efficient in pattern-matching than if transformations are totally random. In the former implementation, the population evolves to a stationary state where agents with different automata rules coexist. (paper)

  3. Inability to acquire spatial information and deploy spatial search strategies in mice with lesions in dorsomedial striatum.

    Science.gov (United States)

    Pooters, Tine; Gantois, Ilse; Vermaercke, Ben; D'Hooge, Rudi

    2016-02-01

    Dorsal striatum has been shown to contribute to spatial learning and memory, but the role of striatal subregions in this important aspect of cognitive functioning remains unclear. Moreover, the spatial-cognitive mechanisms that underlie the involvement of these regions in spatial navigation have scarcely been studied. We therefore compared spatial learning and memory performance in mice with lesions in dorsomedial (DMS) and dorsolateral striatum (DLS) using the hidden-platform version of the Morris water maze (MWM) task. Compared to sham-operated controls, animals with DMS damage were impaired during MWM acquisition training. These mice displayed delayed spatial learning, increased thigmotaxis, and increased search distance to the platform, in the absence of major motor dysfunction, working memory defects or changes in anxiety or exploration. They failed to show a preference for the target quadrant during probe trials, which further indicates that spatial reference memory was impaired in these animals. Search strategy analysis moreover demonstrated that DMS-lesioned mice were unable to deploy cognitively advanced spatial search strategies. Conversely, MWM performance was barely affected in animals with lesions in DLS. In conclusion, our results indicate that DMS and DLS display differential functional involvement in spatial learning and memory. Our results show that DMS, but not DLS, is crucial for the ability of mice to acquire spatial information and their subsequent deployment of spatial search strategies. These data clearly identify DMS as a crucial brain structure for spatial learning and memory, which could explain the occurrence of neurocognitive impairments in brain disorders that affect the dorsal striatum. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Implications of structural genomics target selection strategies: Pfam5000, whole genome, and random approaches

    Energy Technology Data Exchange (ETDEWEB)

    Chandonia, John-Marc; Brenner, Steven E.

    2004-07-14

    The structural genomics project is an international effort to determine the three-dimensional shapes of all important biological macromolecules, with a primary focus on proteins. Target proteins should be selected according to a strategy which is medically and biologically relevant, of good value, and tractable. As an option to consider, we present the Pfam5000 strategy, which involves selecting the 5000 most important families from the Pfam database as sources for targets. We compare the Pfam5000 strategy to several other proposed strategies that would require similar numbers of targets. These include including complete solution of several small to moderately sized bacterial proteomes, partial coverage of the human proteome, and random selection of approximately 5000 targets from sequenced genomes. We measure the impact that successful implementation of these strategies would have upon structural interpretation of the proteins in Swiss-Prot, TrEMBL, and 131 complete proteomes (including 10 of eukaryotes) from the Proteome Analysis database at EBI. Solving the structures of proteins from the 5000 largest Pfam families would allow accurate fold assignment for approximately 68 percent of all prokaryotic proteins (covering 59 percent of residues) and 61 percent of eukaryotic proteins (40 percent of residues). More fine-grained coverage which would allow accurate modeling of these proteins would require an order of magnitude more targets. The Pfam5000 strategy may be modified in several ways, for example to focus on larger families, bacterial sequences, or eukaryotic sequences; as long as secondary consideration is given to large families within Pfam, coverage results vary only slightly. In contrast, focusing structural genomics on a single tractable genome would have only a limited impact in structural knowledge of other proteomes: a significant fraction (about 30-40 percent of the proteins, and 40-60 percent of the residues) of each proteome is classified in small

  5. Looking for trouble: a description of oculomotor search strategies during live CCTV operation

    OpenAIRE

    Stainer, Matthew J.; Scott-Brown, Kenneth C.; Tatler, Benjamin W.

    2013-01-01

    Recent research has begun to address how CCTV operators in the modern control room attempt to search for crime (e.g., Howard et al., 2011). However, an often-neglected element of the CCTV task is that the operators have at their disposal a multiplexed wall of scenes, and a single spot-monitor on which they can select any of these feeds for inspection. Here we examined how 2 trained CCTV operators used these sources of information to search from crime during a morning, afternoon, and night-tim...

  6. Transfusion strategy in hematological intensive care unit: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Chantepie, Sylvain P; Mear, Jean-Baptiste; Guittet, Lydia; Dervaux, Benoît; Marolleau, Jean-Pierre; Jardin, Fabrice; Dutheil, Jean-Jacques; Parienti, Jean-Jacques; Vilque, Jean-Pierre; Reman, Oumedaly

    2015-11-23

    Packed red blood cell (PRBC) transfusion is required in hematology patients treated with chemotherapy for acute leukemia, autologous (auto) or allogeneic (allo) hematopoietic stem cell transplantation (HSCT). In certain situations like septic shock, hip surgery, coronary disease or gastrointestinal hemorrhage, a restrictive transfusion strategy is associated with a reduction of infection and death. A transfusion strategy using a single PRBC unit has been retrospectively investigated and showed a safe reduction of PRBC consumption and costs. We therefore designed a study to prospectively demonstrate that the transfusion of a single PRBC unit is safe and not inferior to standard care. The 1versus2 trial is a randomized trial which will determine if a single-unit transfusion policy is not inferior to a double-unit transfusion policy. The primary endpoint is the incidence of severe complication (grade ≥ 3) defined as stroke, transient ischemic attack, acute coronary syndrome, heart failure, elevated troponin level, intensive care unit transfer, death, new pulmonary infiltrates, and transfusion-related infections during hospital stays. The secondary endpoint is the number of PRBC units transfused per patient per hospital stay. Two hundred and thirty patients will be randomized to receive a single unit or double unit every time the hemoglobin level is less than 8 g/dL. All patients admitted for induction remission chemotherapy, auto-HSCT or allo-HSCT in hematology intensive care units will be eligible for inclusion. Sample size calculation has determined that a patient population of 230 will be required to prove that the 1-unit PRBC strategy is non-inferior to the 2-unit PRBC strategy. Hemoglobin threshold for transfusion is below 8 g/dL. Estimated percentage of complication-free hospital stays is 93 %. In a non-inferiority hypothesis, the number of patients to include is 230 with a power of 90 % and an alpha risk of 5 %. 14-128; Clinicaltrials.gov NCT02461264

  7. A general parallelization strategy for random path based geostatistical simulation methods

    Science.gov (United States)

    Mariethoz, Grégoire

    2010-07-01

    The size of simulation grids used for numerical models has increased by many orders of magnitude in the past years, and this trend is likely to continue. Efficient pixel-based geostatistical simulation algorithms have been developed, but for very large grids and complex spatial models, the computational burden remains heavy. As cluster computers become widely available, using parallel strategies is a natural step for increasing the usable grid size and the complexity of the models. These strategies must profit from of the possibilities offered by machines with a large number of processors. On such machines, the bottleneck is often the communication time between processors. We present a strategy distributing grid nodes among all available processors while minimizing communication and latency times. It consists in centralizing the simulation on a master processor that calls other slave processors as if they were functions simulating one node every time. The key is to decouple the sending and the receiving operations to avoid synchronization. Centralization allows having a conflict management system ensuring that nodes being simulated simultaneously do not interfere in terms of neighborhood. The strategy is computationally efficient and is versatile enough to be applicable to all random path based simulation methods.

  8. Active implementation strategy of CONSORT adherence by a dental specialty journal improved randomized clinical trial reporting.

    Science.gov (United States)

    Pandis, Nikolaos; Shamseer, Larissa; Kokich, Vincent G; Fleming, Padhraig S; Moher, David

    2014-09-01

    To describe a novel CONsolidated Standards of Reporting Trials (CONSORT) adherence strategy implemented by the American Journal of Orthodontics and Dentofacial Orthopedics (AJO-DO) and to report its impact on the completeness of reporting of published trials. The AJO-DO CONSORT adherence strategy, initiated in June 2011, involves active assessment of randomized clinical trial (RCT) reporting during the editorial process. The completeness of reporting CONSORT items was compared between trials submitted and published during the implementation period (July 2011 to September 2013) and trials published between August 2007 and July 2009. Of the 42 RCTs submitted (July 2011 to September 2013), 23 were considered for publication and assessed for completeness of reporting, seven of which were eventually published. For all published RCTs between 2007 and 2009 (n = 20), completeness of reporting by CONSORT item ranged from 0% to 100% (Median = 40%, interquartile range = 60%). All published trials in 2011-2013, reported 33 of 37 CONSORT (sub) items. Four CONSORT 2010 checklist items remained problematic even after implementation of the adherence strategy: changes to methods (3b), changes to outcomes (6b) after the trial commenced, interim analysis (7b), and trial stopping (14b), which are typically only reported when applicable. Trials published following implementation of the AJO-DO CONSORT adherence strategy completely reported more CONSORT items than those published or submitted previously. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Implementation of client versus care-provider strategies to improve external cephalic version rates: a cluster randomized controlled trial

    NARCIS (Netherlands)

    Vlemmix, Floortje; Rosman, Ageeth N.; Rijnders, Marlies E.; Beuckens, Antje; Opmeer, Brent C.; Mol, Ben W. J.; Kok, Marjolein; Fleuren, Margot A. H.

    2015-01-01

    To determine the effectiveness of a client or care-provider strategy to improve the implementation of external cephalic version. Cluster randomized controlled trial. Twenty-five clusters; hospitals and their referring midwifery practices randomly selected in the Netherlands. Singleton breech

  10. Implementation of client versus care-provider strategies to improve external cephalic version rates: a cluster randomized controlled trial

    NARCIS (Netherlands)

    Vlemmix, F.; Rosman, A.N.; Rijnders, M.E.; Beuckens, A.; Opmeer, B.C.; Mol, B.W.J.; Kok, M.; Fleuren, M.A.H.

    2015-01-01

    Onjective: To determine the effectiveness of a client or care-provider strategy to improve the implementation of external cephalic version. Design: Cluster randomized controlled trial.Setting: Twenty-five clusters; hospitals and their referring midwifery practices randomly selected in the

  11. Identification of risk conditions for the development of adrenal disorders: how optimized PubMed search strategies makes the difference.

    Science.gov (United States)

    Guaraldi, Federica; Parasiliti-Caprino, Mirko; Goggi, Riccardo; Beccuti, Guglielmo; Grottoli, Silvia; Arvat, Emanuela; Ghizzoni, Lucia; Ghigo, Ezio; Giordano, Roberta; Gori, Davide

    2014-12-01

    The exponential growth of scientific literature available through electronic databases (namely PubMed) has increased the chance of finding interesting articles. At the same time, search has become more complicated, time consuming, and at risk of missing important information. Therefore, optimized strategies have to be adopted to maximize searching impact. The aim of this study was to formulate efficient strings to search PubMed for etiologic associations between adrenal disorders (ADs) and other conditions. A comprehensive list of terms identifying endogenous conditions primarily affecting adrenals was compiled. An ad hoc analysis was performed to find the best way to express each term in order to find the highest number of potentially pertinent articles in PubMed. A predefined number of retrieved abstracts were read to assess their association with ADs' etiology. A more sensitive (providing the largest literature coverage) and a more specific (including only those terms retrieving >40 % of potentially pertinent articles) string were formulated. Various researches were performed to assess strings' ability to identify articles of interest in comparison with non-optimized literature searches. We formulated optimized, ready applicable tools for the identification of the literature assessing etiologic associations in the field of ADs using PubMed, and demonstrated the advantages deriving from their application. Detailed description of the methodological process is also provided, so that this work can easily be translated to other fields of practice.

  12. Information Retrieval Strategies of Millennial Undergraduate Students in Web and Library Database Searches

    Science.gov (United States)

    Porter, Brandi

    2009-01-01

    Millennial students make up a large portion of undergraduate students attending colleges and universities, and they have a variety of online resources available to them to complete academically related information searches, primarily Web based and library-based online information retrieval systems. The content, ease of use, and required search…

  13. Children’s information retrieval: beyond examining search strategies and interfaces

    NARCIS (Netherlands)

    Jochmann-Mannak, Hanna; Huibers, Theo W.C.; Sanders, T.J.M.

    2008-01-01

    The study of children’s information retrieval is still for the greater part untouched territory. Meanwhile, children can become lost in the digital information world, because they are confronted with search interfaces, both designed by and for adults. Most current research on children’s information

  14. A systematic examination of a random sampling strategy for source apportionment calculations.

    Science.gov (United States)

    Andersson, August

    2011-12-15

    Estimating the relative contributions from multiple potential sources of a specific component in a mixed environmental matrix is a general challenge in diverse fields such as atmospheric, environmental and earth sciences. Perhaps the most common strategy for tackling such problems is by setting up a system of linear equations for the fractional influence of different sources. Even though an algebraic solution of this approach is possible for the common situation with N+1 sources and N source markers, such methodology introduces a bias, since it is implicitly assumed that the calculated fractions and the corresponding uncertainties are independent of the variability of the source distributions. Here, a random sampling (RS) strategy for accounting for such statistical bias is examined by investigating rationally designed synthetic data sets. This random sampling methodology is found to be robust and accurate with respect to reproducibility and predictability. This method is also compared to a numerical integration solution for a two-source situation where source variability also is included. A general observation from this examination is that the variability of the source profiles not only affects the calculated precision but also the mean/median source contributions. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. A Novel Randomized Search Technique for Multiple Mobile Robot Paths Planning In Repetitive Dynamic Environment

    Directory of Open Access Journals (Sweden)

    Vahid Behravesh

    2012-08-01

    Full Text Available Presented article is studying the issue of path navigating for numerous robots. Our presented approach is based on both priority and the robust method for path finding in repetitive dynamic. Presented model can be generally implementable and useable: We do not assume any restriction regarding the quantity of levels of freedom for robots, and robots of diverse kinds can be applied at the same time. We proposed a random method and hill-climbing technique in the area based on precedence plans, which is used to determine a solution to a given trajectory planning problem and to make less the extent of total track. Our method plans trajectories for particular robots in the setting-time scope. Therefore, in order to specifying the interval of constant objects similar to other robots and the extent of the tracks which is traversed. For measuring the hazard for robots to conflict with each other it applied a method based on probability of the movements of robots. This algorithm applied to real robots with successful results. The proposed method performed and judged on both real robots and in simulation. We performed sequence of100tests with 8 robots for comparing with coordination method and current performances are effective. However, maximizing the performance is still possible. These performances estimations performed on Windows operating system and 3GHz Intel Pentium IV with and compiles with GCC 3.4. We used our PCGA robot for all experiments.  For a large environment of 19×15m2where we accomplished 40tests, our model is competent to plan high-quality paths in a severely short time (less than a second. Moreover, this article utilized lookup tables to keep expenses the formerly navigated robots made, increasing the number of robots don’t expand computation time.

  16. Hybrid Multiple Soft-Sensor Models of Grinding Granularity Based on Cuckoo Searching Algorithm and Hysteresis Switching Strategy

    Directory of Open Access Journals (Sweden)

    Jie-Sheng Wang

    2015-01-01

    Full Text Available According to the characteristics of grinding process and accuracy requirements of technical indicators, a hybrid multiple soft-sensor modeling method of grinding granularity is proposed based on cuckoo searching (CS algorithm and hysteresis switching (HS strategy. Firstly, a mechanism soft-sensor model of grinding granularity is deduced based on the technique characteristics and a lot of experimental data of grinding process. Meanwhile, the BP neural network soft-sensor model and wavelet neural network (WNN soft-sensor model are set up. Then, the hybrid multiple soft-sensor model based on the hysteresis switching strategy is realized. That is to say, the optimum model is selected as the current predictive model according to the switching performance index at each sampling instant. Finally the cuckoo searching algorithm is adopted to optimize the performance parameters of hysteresis switching strategy. Simulation results show that the proposed model has better generalization results and prediction precision, which can satisfy the real-time control requirements of grinding classification process.

  17. Strategies to enhance venous thromboprophylaxis in hospitalized medical patients (SENTRY: a pilot cluster randomized trial

    Directory of Open Access Journals (Sweden)

    Pai Menaka

    2013-01-01

    Full Text Available Abstract Background Venous thromboembolism (VTE is a common preventable cause of mortality in hospitalized medical patients. Despite rigorous randomized trials generating strong recommendations for anticoagulant use to prevent VTE, nearly 40% of medical patients receive inappropriate thromboprophylaxis. Knowledge-translation strategies are needed to bridge this gap. Methods We conducted a 16-week pilot cluster randomized controlled trial (RCT to determine the proportion of medical patients that were appropriately managed for thromboprophylaxis (according to the American College of Chest Physician guidelines within 24 hours of admission, through the use of a multicomponent knowledge-translation intervention. Our primary goal was to determine the feasibility of conducting this study on a larger scale. The intervention comprised clinician education, a paper-based VTE risk assessment algorithm, printed physicians’ orders, and audit and feedback sessions. Medical wards at six hospitals (representing clusters in Ontario, Canada were included; three were randomized to the multicomponent intervention and three to usual care (i.e., no active strategies for thromboprophylaxis in place. Blinding was not used. Results A total of 2,611 patients (1,154 in the intervention and 1,457 in the control group were eligible and included in the analysis. This multicomponent intervention did not lead to a significant difference in appropriate VTE prophylaxis rates between intervention and control hospitals (appropriate management rate odds ratio = 0.80; 95% confidence interval: 0.50, 1.28; p = 0.36; intra-class correlation coefficient: 0.022, and thus was not considered feasible. Major barriers to effective knowledge translation were poor attendance by clinical staff at education and feedback sessions, difficulty locating preprinted orders, and lack of involvement by clinical and administrative leaders. We identified several factors that may increase uptake of a VTE

  18. Implementing school nursing strategies to reduce LGBTQ adolescent suicide: a randomized cluster trial study protocol.

    Science.gov (United States)

    Willging, Cathleen E; Green, Amy E; Ramos, Mary M

    2016-10-22

    Reducing youth suicide in the United States (U.S.) is a national public health priority, and lesbian, gay, bisexual, transgender, and queer or questioning (LGBTQ) youth are at elevated risk. The Centers for Disease Control and Prevention (CDC) endorses six evidence-based (EB) strategies that center on meeting the needs of LGBTQ youth in schools; however, fewer than 6 % of U.S. schools implement all of them. The proposed intervention model, "RLAS" (Implementing School Nursing Strategies to Reduce LGBTQ Adolescent Suicide), builds on the Exploration, Preparation, Implementation, and Sustainment (EPIS) conceptual framework and the Dynamic Adaptation Process (DAP) to implement EB strategies in U.S. high schools. The DAP accounts for the multilevel context of school settings and uses Implementation Resource Teams (IRTs) to facilitate appropriate expertise, advise on acceptable adaptations, and provide data feedback to make schools implementation ready and prepared to sustain changes. Mixed methods will be used to examine individual, school, and community factors influencing both implementation process and youth outcomes. A cluster randomized controlled trial will assess whether LGBTQ students and their peers in RLAS intervention schools (n = 20) report reductions in suicidality, depression, substance use, bullying, and truancy related to safety concerns compared to those in usual care schools (n = 20). Implementation progress and fidelity for each EB strategy in RLAS intervention schools will be examined using a modified version of the Stages of Implementation Completion checklist. During the implementation and sustainment phases, annual focus groups will be conducted with the 20 IRTs to document their experiences identifying and advancing adaptation supports to facilitate use of EB strategies and their perceptions of the DAP. The DAP represents a data-informed, collaborative, multiple stakeholder approach to progress from exploration to sustainment and obtain

  19. Implementing school nursing strategies to reduce LGBTQ adolescent suicide: a randomized cluster trial study protocol

    Directory of Open Access Journals (Sweden)

    Cathleen E. Willging

    2016-10-01

    Full Text Available Abstract Background Reducing youth suicide in the United States (U.S. is a national public health priority, and lesbian, gay, bisexual, transgender, and queer or questioning (LGBTQ youth are at elevated risk. The Centers for Disease Control and Prevention (CDC endorses six evidence-based (EB strategies that center on meeting the needs of LGBTQ youth in schools; however, fewer than 6 % of U.S. schools implement all of them. The proposed intervention model, “RLAS” (Implementing School Nursing Strategies to Reduce LGBTQ Adolescent Suicide, builds on the Exploration, Preparation, Implementation, and Sustainment (EPIS conceptual framework and the Dynamic Adaptation Process (DAP to implement EB strategies in U.S. high schools. The DAP accounts for the multilevel context of school settings and uses Implementation Resource Teams (IRTs to facilitate appropriate expertise, advise on acceptable adaptations, and provide data feedback to make schools implementation ready and prepared to sustain changes. Methods/Design Mixed methods will be used to examine individual, school, and community factors influencing both implementation process and youth outcomes. A cluster randomized controlled trial will assess whether LGBTQ students and their peers in RLAS intervention schools (n = 20 report reductions in suicidality, depression, substance use, bullying, and truancy related to safety concerns compared to those in usual care schools (n = 20. Implementation progress and fidelity for each EB strategy in RLAS intervention schools will be examined using a modified version of the Stages of Implementation Completion checklist. During the implementation and sustainment phases, annual focus groups will be conducted with the 20 IRTs to document their experiences identifying and advancing adaptation supports to facilitate use of EB strategies and their perceptions of the DAP. Discussion The DAP represents a data-informed, collaborative, multiple stakeholder

  20. Anaesthesiological strategies in elective craniotomy: randomized, equivalence, open trial--the NeuroMorfeo trial.

    Science.gov (United States)

    Citerio, Giuseppe; Franzosi, Maria Grazia; Latini, Roberto; Masson, Serge; Barlera, Simona; Guzzetti, Stefano; Pesenti, Antonio

    2009-04-06

    Many studies have attempted to determine the "best" anaesthetic technique for neurosurgical procedures in patients without intracranial hypertension. So far, no study comparing intravenous (IA) with volatile-based neuroanaesthesia (VA) has been able to demonstrate major outcome differences nor a superiority of one of the two strategies in patients undergoing elective supratentorial neurosurgery. Therefore, current practice varies and includes the use of either volatile or intravenous anaesthetics in addition to narcotics. Actually the choice of the anaesthesiological strategy depends only on the anaesthetists' preferences or institutional policies. This trial, named NeuroMorfeo, aims to assess the equivalence between volatile and intravenous anaesthetics for neurosurgical procedures. NeuroMorfeo is a multicenter, randomized, open label, controlled trial, based on an equivalence design. Patients aged between 18 and 75 years, scheduled for elective craniotomy for supratentorial lesion without signs of intracranial hypertension, in good physical state (ASA I-III) and Glasgow Coma Scale (GCS) equal to 15, are randomly assigned to one of three anaesthesiological strategies (two VA arms, sevoflurane + fentanyl or sevoflurane + remifentanil, and one IA, propofol + remifentanil). The equivalence between intravenous and volatile-based neuroanaesthesia will be evaluated by comparing the intervals required to reach, after anaesthesia discontinuation, a modified Aldrete score > or = 9 (primary end-point). Two statistical comparisons have been planned: 1) sevoflurane + fentanyl vs. propofol + remifentanil; 2) sevoflurane + remifentanil vs. propofol + remifentanil. Secondary end-points include: an assessment of neurovegetative stress based on (a) measurement of urinary catecholamines and plasma and urinary cortisol and (b) estimate of sympathetic/parasympathetic balance by power spectrum analyses of electrocardiographic tracings recorded during anaesthesia; intraoperative

  1. Millennial Students’ Online Search Strategies are Associated With Their Mental Models of Search. A Review of: Holman, L. (2011. Millennial students’ mental models of search: Implications for academic librarians and database developers. Journal of Academic Librarianship, 37(1, 19-27. doi:10.1016/j.acalib.2010.10.003

    Directory of Open Access Journals (Sweden)

    Leslie Bussert

    2011-09-01

    Full Text Available Objective – To examine first-year college students’ information seeking behaviours and determine whether their mental models of the search process influence their ability to effectively search for and find scholarly materials.Design – Mixed methods including contextual inquiry, concept mapping, observation, and interviews.Setting – University of Baltimore, a public institution in Maryland, United States of America, offering undergraduate, graduate, and professional degrees.Subjects – A total of 21 first-year undergraduate students, ages 16 to 19 years, undertaking research assignments for which they chose to use online resources.Methods – First-year students were recruited in the fall of 2008 and met with the researcher in a university usability lab for about one hour over a three week period. The researcher observed and videotaped the students as they conducted research in their chosen search engines or article databases. The searches were captured using software, and students were encouraged to think aloud about their research process, search strategies, and anticipated search results. Observation sessions concluded with a 10-question interview incorporating a review of the keywords the student used, the student’s reflection on the success of his or her searches, and possible alternate keywords. The interview also offered prompts to help the researcher learn about students’ conceptualizations of search tools’ utilization of keywords to generate results. The researcher then asked the students to provide a visual diagram of the relationship between their search terms and the items retrieved in the search tool.Data were analyzed by identifying the 21 different search tools used by the students and categorizing all 210 searches and student diagrams for further analysis. A scheme similar to Guinee, Eagleton, and Hall’s (2003 characterized the student searches into four categories: simple single-term searches, topic plus focus

  2. Commissioning of the CMS muon detector and development of generic search strategies for new physics

    International Nuclear Information System (INIS)

    Biallass, Philipp Alexander

    2009-01-01

    The detection and reconstruction of cosmic muon rays is important for the commissioning phase and alignment of the Compact Muon Solenoid experiment (CMS), in particular during the early phases of operation with physics collisions. In this context the Magnet Test/Cosmic Challenge (MTCC) with its comprehensive cosmic data taking periods including the presence of the magnetic field has been like a dress rehearsal of detector hardware and software for the upcoming start-up of the CMS detector. In addition to data taking also the comparison with simulated events is a crucial part of physics analyses. The first part of this thesis introduces a new cosmic muon generator, CMSCGEN, and it presents its validation by comparing its predictions with data from MTCC. As an example, results from a reconstruction study using the barrel muon system are shown, comparing data and Monte Carlo prediction at the level of single chambers up to reconstructed tracks including momentum measurements. Since leptons (electrons, muons) constitute very clean signatures for signals of new physics these commissioning and alignment procedures are also vital to most physics analyses. In the second part of this thesis a model independent search approach for new physics within CMS is presented, utilizing events with leptons and relying only on the knowledge of the Standard Model simulation. Such an analysis can contribute to the understanding of the detector and the tuning of the event generators. Due to the absence of a theoretical bias this approach is sensitive to a variety of models, including those not yet thought of. Within this feasibility study events are classified according to their particle content (muons, electrons, photons, jets, missing energy) into so called event classes. A broad scan of various distributions is performed, identifying significant deviations from the SM Monte Carlo simulation. The importance of systematic uncertainties is outlined, which are taken into account rigorously

  3. Commissioning of the CMS muon detector and development of generic search strategies for new physics

    Energy Technology Data Exchange (ETDEWEB)

    Biallass, Philipp Alexander

    2009-03-27

    The detection and reconstruction of cosmic muon rays is important for the commissioning phase and alignment of the Compact Muon Solenoid experiment (CMS), in particular during the early phases of operation with physics collisions. In this context the Magnet Test/Cosmic Challenge (MTCC) with its comprehensive cosmic data taking periods including the presence of the magnetic field has been like a dress rehearsal of detector hardware and software for the upcoming start-up of the CMS detector. In addition to data taking also the comparison with simulated events is a crucial part of physics analyses. The first part of this thesis introduces a new cosmic muon generator, CMSCGEN, and it presents its validation by comparing its predictions with data from MTCC. As an example, results from a reconstruction study using the barrel muon system are shown, comparing data and Monte Carlo prediction at the level of single chambers up to reconstructed tracks including momentum measurements. Since leptons (electrons, muons) constitute very clean signatures for signals of new physics these commissioning and alignment procedures are also vital to most physics analyses. In the second part of this thesis a model independent search approach for new physics within CMS is presented, utilizing events with leptons and relying only on the knowledge of the Standard Model simulation. Such an analysis can contribute to the understanding of the detector and the tuning of the event generators. Due to the absence of a theoretical bias this approach is sensitive to a variety of models, including those not yet thought of. Within this feasibility study events are classified according to their particle content (muons, electrons, photons, jets, missing energy) into so called event classes. A broad scan of various distributions is performed, identifying significant deviations from the SM Monte Carlo simulation. The importance of systematic uncertainties is outlined, which are taken into account rigorously

  4. Towards a new strategy of searching for QCD phase transition in heavy ion collisions

    International Nuclear Information System (INIS)

    Ploszajczak, M.; Shanenko, A.A.; Toneev, V.D.; Joint Inst. for Nuclear Research, Dubna

    1995-01-01

    The Hung and Shuryak arguments are reconsidered in favour of searching for the deconfinement phase transition in heavy ion collisions downward from the nominal SPS energy, at E lab ∼ 30 GeV/A where the fireball lifetime is the longest one. Using the recent lattice QCD data and the mixed phase model, it is shown that the deconfinement transition might occur at the bombarding energies as low as E lab = 3-5 GeV/A. Attention is drawn to the study of the mixed phase of nuclear matter in the collision energy range E lab = 2-10 GeV/A. (author)

  5. The use of a genetic algorithm-based search strategy in geostatistics: application to a set of anisotropic piezometric head data

    Science.gov (United States)

    Abedini, M. J.; Nasseri, M.; Burn, D. H.

    2012-04-01

    In any geostatistical study, an important consideration is the choice of an appropriate, repeatable, and objective search strategy that controls the nearby samples to be included in the location-specific estimation procedure. Almost all geostatistical software available in the market puts the onus on the user to supply search strategy parameters in a heuristic manner. These parameters are solely controlled by geographical coordinates that are defined for the entire area under study, and the user has no guidance as to how to choose these parameters. The main thesis of the current study is that the selection of search strategy parameters has to be driven by data—both the spatial coordinates and the sample values—and cannot be chosen beforehand. For this purpose, a genetic-algorithm-based ordinary kriging with moving neighborhood technique is proposed. The search capability of a genetic algorithm is exploited to search the feature space for appropriate, either local or global, search strategy parameters. Radius of circle/sphere and/or radii of standard or rotated ellipse/ellipsoid are considered as the decision variables to be optimized by GA. The superiority of GA-based ordinary kriging is demonstrated through application to the Wolfcamp Aquifer piezometric head data. Assessment of numerical results showed that definition of search strategy parameters based on both geographical coordinates and sample values improves cross-validation statistics when compared with that based on geographical coordinates alone. In the case of a variable search neighborhood for each estimation point, optimization of local search strategy parameters for an elliptical support domain—the orientation of which is dictated by anisotropic axes—via GA was able to capture the dynamics of piezometric head in west Texas/New Mexico in an efficient way.

  6. Building with Nature: in search of resilient storm surge protection strategies

    NARCIS (Netherlands)

    Slobbe, van E.J.J.; Vriend, de H.J.; Aarninkhof, S.G.J.; Lulofs, K.; Vries, de M.; Dircke, P.

    2013-01-01

    Low-lying, densely populated coastal areas worldwide are under threat, requiring coastal managers to develop new strategies to cope with land subsidence, sea-level rise and the increasing risk of storm-surge-induced floods. Traditional engineering approaches optimizing for safety are often

  7. Cerebral collateral therapeutics in acute ischemic stroke: A randomized preclinical trial of four modulation strategies.

    Science.gov (United States)

    Beretta, Simone; Versace, Alessandro; Carone, Davide; Riva, Matteo; Dell'Era, Valentina; Cuccione, Elisa; Cai, Ruiyao; Monza, Laura; Pirovano, Silvia; Padovano, Giada; Stiro, Fabio; Presotto, Luca; Paternò, Giovanni; Rossi, Emanuela; Giussani, Carlo; Sganzerla, Erik P; Ferrarese, Carlo

    2017-10-01

    Cerebral collaterals are dynamically recruited after arterial occlusion and highly affect tissue outcome in acute ischemic stroke. We investigated the efficacy and safety of four pathophysiologically distinct strategies for acute modulation of collateral flow (collateral therapeutics) in the rat stroke model of transient middle cerebral artery (MCA) occlusion. A composed randomization design was used to assign rats (n = 118) to receive phenylephrine (induced hypertension), polygeline (intravascular volume load), acetazolamide (cerebral arteriolar vasodilation), head down tilt (HDT) 15° (cerebral blood flow diversion), or no treatment, starting 30 min after MCA occlusion. Compared to untreated animals, treatment with collateral therapeutics was associated with lower infarct volumes (62% relative mean difference; 51.57 mm 3 absolute mean difference; p Collateral therapeutics acutely increased cerebral perfusion in the medial (+40.8%; p collaterals is feasible and provides a tissue-saving effect in the hyperacute phase of ischemic stroke prior to recanalization therapy.

  8. Equilibrium Model of Discrete Dynamic Supply Chain Network with Random Demand and Advertisement Strategy

    Directory of Open Access Journals (Sweden)

    Guitao Zhang

    2014-01-01

    Full Text Available The advertisement can increase the consumers demand; therefore it is one of the most important marketing strategies in the operations management of enterprises. This paper aims to analyze the impact of advertising investment on a discrete dynamic supply chain network which consists of suppliers, manufactures, retailers, and demand markets associated at different tiers under random demand. The impact of advertising investment will last several planning periods besides the current period due to delay effect. Based on noncooperative game theory, variational inequality, and Lagrange dual theory, the optimal economic behaviors of the suppliers, the manufactures, the retailers, and the consumers in the demand markets are modeled. In turn, the supply chain network equilibrium model is proposed and computed by modified project contraction algorithm with fixed step. The effectiveness of the model is illustrated by numerical examples, and managerial insights are obtained through the analysis of advertising investment in multiple periods and advertising delay effect among different periods.

  9. Randomized Approaches for Nearest Neighbor Search in Metric Space When Computing the Pairwise Distance Is Extremely Expensive

    Science.gov (United States)

    Wang, Lusheng; Yang, Yong; Lin, Guohui

    Finding the closest object for a query in a database is a classical problem in computer science. For some modern biological applications, computing the similarity between two objects might be very time consuming. For example, it takes a long time to compute the edit distance between two whole chromosomes and the alignment cost of two 3D protein structures. In this paper, we study the nearest neighbor search problem in metric space, where the pair-wise distance between two objects in the database is known and we want to minimize the number of distances computed on-line between the query and objects in the database in order to find the closest object. We have designed two randomized approaches for indexing metric space databases, where objects are purely described by their distances with each other. Analysis and experiments show that our approaches only need to compute O(logn) objects in order to find the closest object, where n is the total number of objects in the database.

  10. Towards a new strategy of searching for QCD phase transition in heavy ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Ploszajczak, M. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Shanenko, A.A. [Joint Inst. for Nuclear Research, Dubna (Russian Federation). Lab. of Theoretical Physics; Toneev, V.D. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France)]|[Joint Inst. for Nuclear Research, Dubna (Russian Federation). Lab. of Theoretical Physics

    1995-12-31

    The Hung and Shuryak arguments are reconsidered in favour of searching for the deconfinement phase transition in heavy ion collisions downward from the nominal SPS energy, at E{sub lab} {approx} 30 GeV/A where the fireball lifetime is the longest one. Using the recent lattice QCD data and the mixed phase model, it is shown that the deconfinement transition might occur at the bombarding energies as low as E{sub lab} = 3-5 GeV/A. Attention is drawn to the study of the mixed phase of nuclear matter in the collision energy range E{sub lab} = 2-10 GeV/A. (author). 18 refs.

  11. Search for the best timing strategy in high-precision drift chambers

    International Nuclear Information System (INIS)

    Va'vra, J.

    1983-06-01

    Computer simulated drift chamber pulses are used to investigate various possible timing strategies in the drift chambers. In particular, the leading edge, the multiple threshold and the flash ADC timing methods are compared. Although the presented method is general for any drift geometry, we concentrate our discussion on the jet chambers where the drift velocity is about 3 to 5 cm/μsec and the individual ionization clusters are not resolved due to a finite speed of our electronics

  12. Turkey in Search of Relevant Foreign Policy Strategy (2002-2016

    Directory of Open Access Journals (Sweden)

    Urmanov Dayan R.

    2016-06-01

    Full Text Available The main idea of this article is to describe the process of Turkish foreign policy evolvement during the rule of Justice and Development party (JDP. From weak economy and unstable political situation in 2001, JDP quickly formulated a new strategy of foreign policy and stabilized economy. In the article the Turkish foreign policy in the 21st century is divided into several stages which respond to different international threats and circumstances. The first stage was a peacekeeping stage when Turkey tried to stabilize the situation near its borders and implement peace initiatives for the purpose to find new markets and allies. As a result, Turkey formulated a new strategy of foreign policy, called “Zero Problems Policy” which aimed to create a ring of friendly countries on the borders. On the second stage, Turkish foreign policy was more active – Turkey tried to balance among regional power centers and confront with one of the most powerful actors – Israel. Confrontation with Tel Aviv was a preface to the third stage, and today under the influence of “Arab Spring” and desire to change its role in international relations, Turkey refused “Zero Problems Policy” strategy and turned to a new aggressive and revanchist idea – neo- Ottomanism. Ankara tries to build a new regional set of rules where Turkey will play a leading role.

  13. Anaesthesiological strategies in elective craniotomy: randomized, equivalence, open trial – The NeuroMorfeo trial

    Directory of Open Access Journals (Sweden)

    Guzzetti Stefano

    2009-04-01

    Full Text Available Abstract Background Many studies have attempted to determine the "best" anaesthetic technique for neurosurgical procedures in patients without intracranial hypertension. So far, no study comparing intravenous (IA with volatile-based neuroanaesthesia (VA has been able to demonstrate major outcome differences nor a superiority of one of the two strategies in patients undergoing elective supratentorial neurosurgery. Therefore, current practice varies and includes the use of either volatile or intravenous anaesthetics in addition to narcotics. Actually the choice of the anaestesiological strategy depends only on the anaesthetists' preferences or institutional policies. This trial, named NeuroMorfeo, aims to assess the equivalence between volatile and intravenous anaesthetics for neurosurgical procedures. Methods/Design NeuroMorfeo is a multicenter, randomized, open label, controlled trial, based on an equivalence design. Patients aged between 18 and 75 years, scheduled for elective craniotomy for supratentorial lesion without signs of intracranial hypertension, in good physical state (ASA I-III and Glasgow Coma Scale (GCS equal to 15, are randomly assigned to one of three anaesthesiological strategies (two VA arms, sevoflurane + fentanyl or sevoflurane + remifentanil, and one IA, propofol + remifentanil. The equivalence between intravenous and volatile-based neuroanaesthesia will be evaluated by comparing the intervals required to reach, after anaesthesia discontinuation, a modified Aldrete score ≥ 9 (primary end-point. Two statistical comparisons have been planned: 1 sevoflurane + fentanyl vs. propofol + remifentanil; 2 sevoflurane + remifentanil vs. propofol + remifentanil. Secondary end-points include: an assessment of neurovegetative stress based on (a measurement of urinary catecholamines and plasma and urinary cortisol and (b estimate of sympathetic/parasympathetic balance by power spectrum analyses of electrocardiographic tracings recorded

  14. Sexual Orientation-Related Differences in Virtual Spatial Navigation and Spatial Search Strategies.

    Science.gov (United States)

    Rahman, Qazi; Sharp, Jonathan; McVeigh, Meadhbh; Ho, Man-Ling

    2017-07-01

    Spatial abilities are generally hypothesized to differ between men and women, and people with different sexual orientations. According to the cross-sex shift hypothesis, gay men are hypothesized to perform in the direction of heterosexual women and lesbian women in the direction of heterosexual men on cognitive tests. This study investigated sexual orientation differences in spatial navigation and strategy during a virtual Morris water maze task (VMWM). Forty-four heterosexual men, 43 heterosexual women, 39 gay men, and 34 lesbian/bisexual women (aged 18-54 years) navigated a desktop VMWM and completed measures of intelligence, handedness, and childhood gender nonconformity (CGN). We quantified spatial learning (hidden platform trials), probe trial performance, and cued navigation (visible platform trials). Spatial strategies during hidden and probe trials were classified into visual scanning, landmark use, thigmotaxis/circling, and enfilading. In general, heterosexual men scored better than women and gay men on some spatial learning and probe trial measures and used more visual scan strategies. However, some differences disappeared after controlling for age and estimated IQ (e.g., in visual scanning heterosexual men differed from women but not gay men). Heterosexual women did not differ from lesbian/bisexual women. For both sexes, visual scanning predicted probe trial performance. More feminine CGN scores were associated with lower performance among men and greater performance among women on specific spatial learning or probe trial measures. These results provide mixed evidence for the cross-sex shift hypothesis of sexual orientation-related differences in spatial cognition.

  15. Multiplicity of Mathematical Modeling Strategies to Search for Molecular and Cellular Insights into Bacteria Lung Infection.

    Science.gov (United States)

    Cantone, Martina; Santos, Guido; Wentker, Pia; Lai, Xin; Vera, Julio

    2017-01-01

    Even today two bacterial lung infections, namely pneumonia and tuberculosis, are among the 10 most frequent causes of death worldwide. These infections still lack effective treatments in many developing countries and in immunocompromised populations like infants, elderly people and transplanted patients. The interaction between bacteria and the host is a complex system of interlinked intercellular and the intracellular processes, enriched in regulatory structures like positive and negative feedback loops. Severe pathological condition can emerge when the immune system of the host fails to neutralize the infection. This failure can result in systemic spreading of pathogens or overwhelming immune response followed by a systemic inflammatory response. Mathematical modeling is a promising tool to dissect the complexity underlying pathogenesis of bacterial lung infection at the molecular, cellular and tissue levels, and also at the interfaces among levels. In this article, we introduce mathematical and computational modeling frameworks that can be used for investigating molecular and cellular mechanisms underlying bacterial lung infection. Then, we compile and discuss published results on the modeling of regulatory pathways and cell populations relevant for lung infection and inflammation. Finally, we discuss how to make use of this multiplicity of modeling approaches to open new avenues in the search of the molecular and cellular mechanisms underlying bacterial infection in the lung.

  16. Misuse of randomization

    DEFF Research Database (Denmark)

    Liu, Jianping; Kjaergard, Lise Lotte; Gluud, Christian

    2002-01-01

    The quality of randomization of Chinese randomized trials on herbal medicines for hepatitis B was assessed. Search strategy and inclusion criteria were based on the published protocol. One hundred and seventy-six randomized clinical trials (RCTs) involving 20,452 patients with chronic hepatitis B...... virus (HBV) infection were identified that tested Chinese medicinal herbs. They were published in 49 Chinese journals. Only 10% (18/176) of the studies reported the method by which they randomized patients. Only two reported allocation concealment and were considered as adequate. Twenty percent (30...

  17. A Critical Review of Search Strategies Used in Recent Systematic Reviews Published in Selected Prosthodontic and Implant-Related Journals: Are Systematic Reviews Actually Systematic?

    Science.gov (United States)

    Layton, Danielle

    The aim of this study was to outline how search strategies can be systematic, to examine how the searches in recent systematic reviews in prosthodontic and implant-related journals were structured, and to determine whether the search strategies used in those articles were systematic. A total of 103 articles published as systematic reviews and indexed in Medline between January 2013 and May 2016 were identified from eight prosthodontic and implant journals and reviewed. The search strategies were considered systematic when they met the following criteria: (1) more than one electronic database was searched, (2) more than one searcher was clearly involved, (3) both text words and indexing terms were clearly included in the search strategy, (4) a hand search of selected journals or reference lists was undertaken, (5) gray research was specifically sought, and (6) the articles were published in English and at least one other language. The data were tallied and qualitatively assessed. The majority of articles reported on implants (54%), followed by tooth-supported fixed prosthodontics (13%). A total of 23 different electronic resources were consulted, including Medline (by 100% of articles), the Cochrane Library (52%), and Embase (37%). The majority consulted more than one electronic resource (71%), clearly included more than one searcher (73%), and employed a hand search of either selected journals or reference lists (86%). Less than half used both text words and indexing terms to identify articles (42%), while 15% actively sought gray research. Articles published in languages other than English were considered in 63 reviews, but only 14 had no language restrictions. Of the 103 articles, 5 completed search strategies that met all 6 criteria, and a further 12 met 5 criteria. Two articles did not fulfill any of the criteria. More than 95% of recent prosthodontic and implant review articles published in the selected journals failed to use search strategies that were

  18. Increasing water availability during afterschool snack: evidence, strategies, and partnerships from a group randomized trial.

    Science.gov (United States)

    Giles, Catherine M; Kenney, Erica L; Gortmaker, Steven L; Lee, Rebekka M; Thayer, Julie C; Mont-Ferguson, Helen; Cradock, Angie L

    2012-09-01

    Providing drinking water to U.S. children during school meals is a recommended health promotion strategy and part of national nutrition policy. Urban school systems have struggled with providing drinking water to children, and little is known about how to ensure that water is served, particularly in afterschool settings. To assess the effectiveness of an intervention designed to promote water as the beverage of choice in afterschool programs. The Out of School Nutrition and Physical Activity Initiative (OSNAP) used a community-based collaboration and low-cost strategies to provide water after school. A group RCT was used to evaluate the intervention. Data were collected in 2010-2011 and analyzed in 2011. Twenty afterschool programs in Boston were randomized to intervention or control (delayed intervention). Intervention sites participated in learning collaboratives focused on policy and environmental changes to increase healthy eating, drinking, and physical activity opportunities during afterschool time (materials available at www.osnap.org). Collaboration between Boston Public Schools Food and Nutrition Services, afterschool staff, and researchers established water-delivery systems to ensure children were served water during snack time. Average ounces of water served to children per day was recorded by direct observation at each program at baseline and 6-month follow-up over 5 consecutive school days. Secondary measures directly observed included ounces of other beverages served, other snack components, and water-delivery system. Participation in the intervention was associated with an increased average volume of water served (+3.6 ounces/day; p=0.01) during snack. On average, the intervention led to a daily decrease of 60.9 kcals from beverages served during snack (p=0.03). This study indicates the OSNAP intervention, including strategies to overcome structural barriers and collaboration with key actors, can increase offerings of water during afterschool snack

  19. Cognitive biases and heuristics in medical decision making: a critical review using a systematic search strategy.

    Science.gov (United States)

    Blumenthal-Barby, J S; Krieger, Heather

    2015-05-01

    The role of cognitive biases and heuristics in medical decision making is of growing interest. The purpose of this study was to determine whether studies on cognitive biases and heuristics in medical decision making are based on actual or hypothetical decisions and are conducted with populations that are representative of those who typically make the medical decision; to categorize the types of cognitive biases and heuristics found and whether they are found in patients or in medical personnel; and to critically review the studies based on standard methodological quality criteria. Data sources were original, peer-reviewed, empirical studies on cognitive biases and heuristics in medical decision making found in Ovid Medline, PsycINFO, and the CINAHL databases published in 1980-2013. Predefined exclusion criteria were used to identify 213 studies. During data extraction, information was collected on type of bias or heuristic studied, respondent population, decision type, study type (actual or hypothetical), study method, and study conclusion. Of the 213 studies analyzed, 164 (77%) were based on hypothetical vignettes, and 175 (82%) were conducted with representative populations. Nineteen types of cognitive biases and heuristics were found. Only 34% of studies (n = 73) investigated medical personnel, and 68% (n = 145) confirmed the presence of a bias or heuristic. Each methodological quality criterion was satisfied by more than 50% of the studies, except for sample size and validated instruments/questions. Limitations are that existing terms were used to inform search terms, and study inclusion criteria focused strictly on decision making. Most of the studies on biases and heuristics in medical decision making are based on hypothetical vignettes, raising concerns about applicability of these findings to actual decision making. Biases and heuristics have been underinvestigated in medical personnel compared with patients. © The Author(s) 2014.

  20. Enhancing Artificial Bee Colony Algorithm with Self-Adaptive Searching Strategy and Artificial Immune Network Operators for Global Optimization

    Directory of Open Access Journals (Sweden)

    Tinggui Chen

    2014-01-01

    Full Text Available Artificial bee colony (ABC algorithm, inspired by the intelligent foraging behavior of honey bees, was proposed by Karaboga. It has been shown to be superior to some conventional intelligent algorithms such as genetic algorithm (GA, artificial colony optimization (ACO, and particle swarm optimization (PSO. However, the ABC still has some limitations. For example, ABC can easily get trapped in the local optimum when handing in functions that have a narrow curving valley, a high eccentric ellipse, or complex multimodal functions. As a result, we proposed an enhanced ABC algorithm called EABC by introducing self-adaptive searching strategy and artificial immune network operators to improve the exploitation and exploration. The simulation results tested on a suite of unimodal or multimodal benchmark functions illustrate that the EABC algorithm outperforms ACO, PSO, and the basic ABC in most of the experiments.

  1. Search Strategy of Detector Position For Neutron Source Multiplication Method by Using Detected-Neutron Multiplication Factor

    International Nuclear Information System (INIS)

    Endo, Tomohiro

    2011-01-01

    In this paper, an alternative definition of a neutron multiplication factor, detected-neutron multiplication factor kdet, is produced for the neutron source multiplication method..(NSM). By using kdet, a search strategy of appropriate detector position for NSM is also proposed. The NSM is one of the practical subcritical measurement techniques, i.e., the NSM does not require any special equipment other than a stationary external neutron source and an ordinary neutron detector. Additionally, the NSM method is based on steady-state analysis, so that this technique is very suitable for quasi real-time measurement. It is noted that the correction factors play important roles in order to accurately estimate subcriticality from the measured neutron count rates. The present paper aims to clarify how to correct the subcriticality measured by the NSM method, the physical meaning of the correction factors, and how to reduce the impact of correction factors by setting a neutron detector at an appropriate detector position

  2. Condition-Based Conveyor Belt Replacement Strategy in Lignite Mines with Random Belt Deterioration

    Science.gov (United States)

    Blazej, Ryszard; Jurdziak, Leszek

    2017-12-01

    In Polish lignite surface mines, condition-based belt replacement strategies are applied in order to assure profitable refurbishment of worn out belts performed by external firms specializing in belt maintenance. In two of three lignite mines, staff asses belt condition subjectively during visual inspections. Only one mine applies specialized diagnostic device (HRDS) allowing objective magnetic evaluation of belt core condition in order to choose the most profitable moment for the dismantling of worn out belt segments from conveyors and sending them to the maintenance firm which provides their refurbishment. This article describes the advantages of a new diagnostic device called DiagBelt. It was developed at the Faculty of Geoengineering, Mining and Geology, Wroclaw University of Science and Technology. Economic gains from its application are calculated for the lignite mine and for the belt maintenance firm, taking into account random life (durability) of new and reconditioned belts (after the 1st and the 2nd refurbishment). Recursive calculations for following years allow the estimation of the length and costs of replaced, reconditioned and purchased belts on an annual basis, while the use of the Monte Carlo method allows the estimation of their variability caused by random deterioration of belts. Savings are obtained due to better selection of moments (times) for the replacement of belt segments and die to the possibility to qualify worn out belts for refurbishment without the need to remove their covers. In effect, increased belt durability and lowered share of waste belts (which were not qualified for reconditioning) create savings which can quickly cover expenditures on new diagnostic tools and regular belt inspections in the mine.

  3. Influence network linkages across implementation strategy conditions in a randomized controlled trial of two strategies for scaling up evidence-based practices in public youth-serving systems.

    Science.gov (United States)

    Palinkas, Lawrence A; Holloway, Ian W; Rice, Eric; Brown, C Hendricks; Valente, Thomas W; Chamberlain, Patricia

    2013-11-14

    Given the importance of influence networks in the implementation of evidence-based practices and interventions, it is unclear whether such networks continue to operate as sources of information and advice when they are segmented and disrupted by randomization to different implementation strategy conditions. The present study examines the linkages across implementation strategy conditions of social influence networks of leaders of youth-serving systems in 12 California counties participating in a randomized controlled trial of community development teams (CDTs) to scale up use of an evidence-based practice. Semi-structured interviews were conducted with 38 directors, assistant directors, and program managers of county probation, mental health, and child welfare departments. A web-based survey collected additional quantitative data on information and advice networks of study participants. A mixed-methods approach to data analysis was used to create a sociometric data set (n = 176) to examine linkages between treatment and standard conditions. Of those network members who were affiliated with a county (n = 137), only 6 (4.4%) were directly connected to a member of the opposite implementation strategy condition; 19 (13.9%) were connected by two steps or fewer to a member of the opposite implementation strategy condition; 64 (46.7%) were connected by three or fewer steps to a member of the opposite implementation strategy condition. Most of the indirect steps between individuals who were in different implementation strategy conditions were connections involving a third non-county organizational entity that had an important role in the trial in keeping the implementation strategy conditions separate. When these entities were excluded, the CDT network exhibited fewer components and significantly higher betweenness centralization than did the standard condition network. Although the integrity of the RCT in this instance was not compromised by study participant influence

  4. The Use of Copper Pesticides in Germany and the Search for Minimization and Replacement Strategies

    Directory of Open Access Journals (Sweden)

    Stefan Kuehne

    2017-02-01

    Full Text Available Copper pesticides used to control fungal and bacterial diseases such as grapes downy mildew (Plasmopara viticola, downy mildew of hops (Pseudoperonospora humili, apple scab (Venturia spp., fireblight (Erwinia amylovora and potato late blight (Phytophthora infestans, play an important role in plant protection. In a 2013 survey of copper application in Germany we found, that while the amounts of copper used per hectare in conventional grape (0.8 kg ha−1, hop (1.7 kg ha−1 and potato-farming (0.8 kg ha−1 were well below those used in organic farming (2.3, 2.6 and 1.4 kg ha−1, respectively, they were nearly identical to those used in apple growing (1.4 kg ha−1. Due to the smaller farming area, only 24% (26.5 tonnes of the total amount of copper was applied in organic farming compared to 76% (84.8 tonnes in conventional farming. Since 2001, the Federal Agency for Agriculture and Food (BLE promoted a copper research and minimization strategy which was funded with a total of C10.2 million. Our status quo analysis of research in this field shows that some progress is being made concerning alternative compounds, resistant varieties and decision support systems. However, it also shows that new approaches are not yet able to replace copper pesticides completely, especially in organic farming. In integrated pest management, copper preparations are important for the necessary active substance rotation and successful resistance management. The availability of such products is often essential for organic grapes, hops and fruit production and for extending the organic farming of these crops. We conclude that the complete elimination of copper pesticides is not yet practicable in organic farming as the production of several organic crops would become unprofitable and may lead to organic farmers reverting to conventional production. Several existing copper reduction strategies were, however, identified, and some, like modified forecast models adapted to

  5. Implementation of client versus care-provider strategies to improve external cephalic version rates: a cluster randomized controlled trial.

    Science.gov (United States)

    Vlemmix, Floortje; Rosman, Ageeth N; Rijnders, Marlies E; Beuckens, Antje; Opmeer, Brent C; Mol, Ben W J; Kok, Marjolein; Fleuren, Margot A H

    2015-05-01

    To determine the effectiveness of a client or care-provider strategy to improve the implementation of external cephalic version. Cluster randomized controlled trial. Twenty-five clusters; hospitals and their referring midwifery practices randomly selected in the Netherlands. Singleton breech presentation from 32 weeks of gestation onwards. We randomized clusters to a client strategy (written information leaflets and decision aid), a care-provider strategy (1-day counseling course focused on knowledge and counseling skills), a combined client and care-provider strategy and care-as-usual strategy. We performed an intention-to-treat analysis. Rate of external cephalic version in various strategies. Secondary outcomes were the percentage of women counseled and opting for a version attempt. The overall implementation rate of external cephalic version was 72% (1169 of 1613 eligible clients) with a range between clusters of 8-95%. Neither the client strategy (OR 0.8, 95% CI 0.4-1.5) nor the care-provider strategy (OR 1.2, 95% CI 0.6-2.3) showed significant improvements. Results were comparable when we limited the analysis to those women who were actually offered intervention (OR 0.6, 95% CI 0.3-1.4 and OR 2.0, 95% CI 0.7-4.5). Neither a client nor a care-provider strategy improved the external cephalic version implementation rate for breech presentation, neither with regard to the number of version attempts offered nor the number of women accepting the procedure. © 2015 Nordic Federation of Societies of Obstetrics and Gynecology.

  6. Towards Improved Airborne Fire Detection Systems Using Beetle Inspired Infrared Detection and Fire Searching Strategies

    Directory of Open Access Journals (Sweden)

    Herbert Bousack

    2015-06-01

    Full Text Available Every year forest fires cause severe financial losses in many countries of the world. Additionally, lives of humans as well as of countless animals are often lost. Due to global warming, the problem of wildfires is getting out of control; hence, the burning of thousands of hectares is obviously increasing. Most important, therefore, is the early detection of an emerging fire before its intensity becomes too high. More than ever, a need for early warning systems capable of detecting small fires from distances as large as possible exists. A look to nature shows that pyrophilous “fire beetles” of the genus Melanophila can be regarded as natural airborne fire detection systems because their larvae can only develop in the wood of fire-killed trees. There is evidence that Melanophila beetles can detect large fires from distances of more than 100 km by visual and infrared cues. In a biomimetic approach, a concept has been developed to use the surveying strategy of the “fire beetles” for the reliable detection of a smoke plume of a fire from large distances by means of a basal infrared emission zone. Future infrared sensors necessary for this ability are also inspired by the natural infrared receptors of Melanophila beetles.

  7. From Marx to Marcos - Search of the Subject and the Strategy of Revolution

    Directory of Open Access Journals (Sweden)

    Ilya L. Morozov

    2017-12-01

    Full Text Available The article discusses the evolution of theories of social revolution from the mid-nineteenth to the late twentieth centuries. The author analyzes the basic concepts of theorists and practitioners of the armed revolutionary struggle – from the founder of the classical Communist theory of Karl Marx to the Mexican guerrilla leader Subcomandante Marcos. The author focuses on the analysis of changes in the understanding of the subject (“driving forces” of the left political revolution, as well as the strategy of armed revolutionary struggle. The author comes to the conclusion about the historical evolution of the subject of the revolutionary struggle from major sustainable macro-groups (“classes”, targeted at the armed struggle, to self-born (by the network principle unstructured protest groups, situational leaders, mild forms of the revolutionary struggle, which minimize the armed violence, though do not eliminate it completely. The author substantiates the conclusion about the absence in the modern protest movement of social forces, able to become the subject of revolution socialist orientation. This increases the danger of dominance of the social protest of extremist nationalist and religious political spectra. The author offers two models of response to this threat: the growing influence of the reigning centre-right conservative parties of Russia; return to center-left positions of the social democratic movement of the countries of the European Union.

  8. Searching out the hydrogen absorption/desorption limiting reaction factors: Strategies allowing to increase kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Zeaiter, Ali, E-mail: ali.zeaiter@femto-st.fr; Chapelle, David; Nardin, Philippe

    2015-10-05

    Highlights: • A macro scale thermodynamic model that simulates the response of a FeTi-X hydride tank is performed, and validated experimentally. • A sensibility study to identify the most influent input variables that can changes very largely the reaction rate. - Abstract: Hydrogen gas has become one of the most promising energy carriers. Main breakthrough concerns hydrogen solid storage, specially based on intermetallic material use. Regarding the raw material abundance and cost, the AB type alloy FeTi is an auspicious candidate to store hydrogen. Its absorption/desorption kinetics is a basic hindrance to common use, compared with more usual hydrides. First, discussions based on literature help us identifying the successive steps leading to metal hydriding, and allow to introduce the physical parameters which drive or limit the reaction. This analysis leads us to suggest strategies in order to increase absorption/desorption kinetics. Attention is then paid to a thermofluidodynamic model, allowing to describe a macroscopic solid storage reactor. Thus, we can achieve a simulation which describes the overall reaction inside the hydrogen reactor and, by varying the sub-mentioned parameters (thermal conductivity, the powder granularity, environment heat exchange…), we attempt to hierarchy the reaction limiting factors. These simulations are correlated to absorption/desorption experiments for which pressure, temperature and hydrogen flow are recorded.

  9. STRATEGIES IN SEARCHING HOMOGENEITY IN A FACULTY OF A POSTGRADUATE PROGRAM.

    Science.gov (United States)

    Cecatti, José G; Fernandes, Karayna G; Souza, Renato T; Silveira, Carla; Surita, Fernanda G

    2015-01-01

    The professor plays a fundamental role in a graduate program, considering he/she is who plans and performs a great part of the tasks, and he/she is also responsible for spreading knowledge among students. The professor should use didactical resources for his/her continuous qualification, being responsible for situations favoring the development of students who should learn according to the best and easier way. The homogeneity in the postgraduate program consists of having subgroups of research corresponding to the Areas of Concentration, where each subgroup works with some distinct topics of research. It is desirable that the staff of postgraduate program has a significant and high quality scientific production, homogeneously distributed among them. The professors must systematically search for resources for research in agencies supporting research, not only for sponsoring the studies, but also for adding value to the researchers involved in the whole activities. The postgraduate programs need to support the professional qualification of their staff who should improve their knowledge on epidemiology for clinical studies, ethics in research and teaching skills. Two characteristics of the postgraduate system in Brazil are the nucleation and solidarity, based on the capacity and/or interest of those more structured programs to help those beginners, cooperating with their activities. The Capes (the national governmental agency responsible for coordinating and evaluating all postgraduate programs in Brazil) valorizes the social insertion in the context of postgraduate programs´ activities. It includes the recognition of activities with technological, cultural, educational and social impact as criteria for evaluation of the programs. Does exist an ideal model of postgraduate program? We think that there is no a mathematical formulae nor an ideal model for a postgraduate program. Each institution should make adaptations and search for improvements of their faculty and

  10. Confirmation bias in web-based search: a randomized online study on the effects of expert information and social tags on information search and evaluation.

    Science.gov (United States)

    Schweiger, Stefan; Oeberst, Aileen; Cress, Ulrike

    2014-03-26

    The public typically believes psychotherapy to be more effective than pharmacotherapy for depression treatments. This is not consistent with current scientific evidence, which shows that both types of treatment are about equally effective. The study investigates whether this bias towards psychotherapy guides online information search and whether the bias can be reduced by explicitly providing expert information (in a blog entry) and by providing tag clouds that implicitly reveal experts' evaluations. A total of 174 participants completed a fully automated Web-based study after we invited them via mailing lists. First, participants read two blog posts by experts that either challenged or supported the bias towards psychotherapy. Subsequently, participants searched for information about depression treatment in an online environment that provided more experts' blog posts about the effectiveness of treatments based on alleged research findings. These blogs were organized in a tag cloud; both psychotherapy tags and pharmacotherapy tags were popular. We measured tag and blog post selection, efficacy ratings of the presented treatments, and participants' treatment recommendation after information search. Participants demonstrated a clear bias towards psychotherapy (mean 4.53, SD 1.99) compared to pharmacotherapy (mean 2.73, SD 2.41; t173=7.67, Pinformation search and evaluation. This bias was significantly reduced, however, when participants were exposed to tag clouds with challenging popular tags. Participants facing popular tags challenging their bias (n=61) showed significantly less biased tag selection (F2,168=10.61, Pinformation as presented in blog posts, compared to supporting expert information (n=81), decreased the bias in information search with regard to blog post selection (F1,168=4.32, P=.04, partial eta squared=0.025). No significant effects were found for treatment recommendation (Ps>.33). We conclude that the psychotherapy bias is most effectively

  11. Safety and effects of two red blood cell transfusion strategies in pediatric cardiac surgery patients: a randomized controlled trial

    NARCIS (Netherlands)

    de Gast-Bakker, D. H.; de Wilde, R. B. P.; Hazekamp, M. G.; Sojak, V.; Zwaginga, J. J.; Wolterbeek, R.; de Jonge, E.; Gesink-van der Veer, B. J.

    2013-01-01

    To investigate the safety and effects of a restrictive red blood cell (RBC) transfusion strategy in pediatric cardiac surgery patients. Randomized controlled trial. Pediatric ICU in an academic tertiary care center, Leiden University Medical Center, Leiden, The Netherlands. One hundred seven

  12. A randomized controlled trial of two primary school intervention strategies to prevent early onset tobacco smoking.

    Science.gov (United States)

    Storr, Carla L; Ialongo, Nicholas S; Kellam, Sheppard G; Anthony, James C

    2002-03-01

    In this article, we examine the impact of two universal, grade 1 preventive interventions on the onset of tobacco smoking as assessed in early adolescence. The classroom-centered (CC) intervention was designed to reduce the risk for tobacco smoking by enhancing teachers' behavior management skills in first grade and, thereby, reducing child attention problems and aggressive and shy behavior-known risk behaviors for later substance use. The family-school partnership (FSP) intervention targeted these early risk behaviors via improvements in parent-teacher communication and parents' child behavior management strategies. A cohort of 678 urban, predominately African-American, public school students were randomly assigned to one of three Grade 1 classrooms at entrance to primary school (age 6). One classroom featured the CC intervention, a second the FSP intervention, and the third served as a control classroom. Six years later, 81% of the students completed audio computer-assisted self-interviews. Relative to controls, a modest attenuation in the risk of smoking initiation was found for students who had been assigned to either the CC or FSP intervention classrooms (26% versus 33%) (adjusted relative risk for CC/control contrast=0.57, 95% confidence interval (CI), 0.34-0.96; adjusted relative risk for FSP/control contrast=0.69, 95% CI, 0.50-0.97). Results lend support to targeting the early antecedent risk behaviors for tobacco smoking.

  13. In Search for Anti-Aging Strategy: Can We Rejuvenate Our Aging Stem Cells?

    Directory of Open Access Journals (Sweden)

    Anna Meiliana

    2015-08-01

    Full Text Available BACKGROUND: Recent evidence suggested that we grow old partly because of our stem cells grow old as a result of mechanisms that suppress the development of cancer over a lifetime. We believe that a further, more precise mechanistic understanding of this process will be required before this knowledge can be translated into human anti-aging therapies. CONTENT: A diminished capacity to maintain tissue homeostasis is a central physiological characteristic of aging. As stem cells regulate tissue homeostasis, depletion of stem cell reserves and/or diminished stem cell function have been postulated to contribute to aging. It has further been suggested that accumulated DNA damage could be a principal mechanism underlying age-dependent stem cell decline. It is interesting that many of the rejuvenating interventions act on the stem cell compartments, perhaps reflecting shared genetic and biochemical pathways controlling stem cell function and longevity. Strategy to slow down the aging processes is based on caloric restriction refers to a dietary regimen low in calories but without undernutrition. Sirtuin (SIRT1 and 3, increases longevity by mimicking the beneficial effects of caloric restriction. SIRT3 regulates stress-responsive mitochondrial homeostasis, and more importantly, SIRT3 upregulation rejuvenates aged stem cells in tissues. Resveratrol (3,5,4’-trihydroxystilbene, a natural polyphenol found in grapes and wine, was the most powerful natural activator of SIRT1. In fact, resveratrol treatment has been demonstrated to rescue adult stem cell decline, slow down bodyweight loss, improve trabecular bone structure and mineral density, and significantly extend lifespan. SUMMARY: Tissue-specific stem cells persist throughout the entire lifespan to repair and maintain tissues, but their self-renewal and differentiation potential become dysregulated with aging. Given that adult stem cells are thought to be central to tissue maintenance and organismal

  14. Optimal Power Flow Using Gbest-Guided Cuckoo Search Algorithm with Feedback Control Strategy and Constraint Domination Rule

    Directory of Open Access Journals (Sweden)

    Gonggui Chen

    2017-01-01

    Full Text Available The optimal power flow (OPF is well-known as a significant optimization tool for the security and economic operation of power system, and OPF problem is a complex nonlinear, nondifferentiable programming problem. Thus this paper proposes a Gbest-guided cuckoo search algorithm with the feedback control strategy and constraint domination rule which is named as FCGCS algorithm for solving OPF problem and getting optimal solution. This FCGCS algorithm is guided by the global best solution for strengthening exploitation ability. Feedback control strategy is devised to dynamically regulate the control parameters according to actual and specific feedback value in the simulation process. And the constraint domination rule can efficiently handle inequality constraints on state variables, which is superior to traditional penalty function method. The performance of FCGCS algorithm is tested and validated on the IEEE 30-bus and IEEE 57-bus example systems, and simulation results are compared with different methods obtained from other literatures recently. The comparison results indicate that FCGCS algorithm can provide high-quality feasible solutions for different OPF problems.

  15. Modelling sensory limitation: the role of tree selection, memory and information transfer in bats' roost searching strategies.

    Science.gov (United States)

    Ruczyński, Ireneusz; Bartoń, Kamil A

    2012-01-01

    Sensory limitation plays an important role in the evolution of animal behaviour. Animals have to find objects of interest (e.g. food, shelters, predators). When sensory abilities are strongly limited, animals adjust their behaviour to maximize chances for success. Bats are nocturnal, live in complex environments, are capable of flight and must confront numerous perceptual challenges (e.g. limited sensory range, interfering clutter echoes). This makes them an excellent model for studying the role of compensating behaviours to decrease costs of finding resources. Cavity roosting bats are especially interesting because the availability of tree cavities is often limited, and their quality is vital for bats during the breeding season. From a bat's sensory point of view, cavities are difficult to detect and finding them requires time and energy. However, tree cavities are also long lasting, allowing information transfer among conspecifics. Here, we use a simple simulation model to explore the benefits of tree selection, memory and eavesdropping (compensation behaviours) to searches for tree cavities by bats with short and long perception range. Our model suggests that memory and correct discrimination of tree suitability are the basic strategies decreasing the cost of roost finding, whereas perceptual range plays a minor role in this process. Additionally, eavesdropping constitutes a buffer that reduces the costs of finding new resources (such as roosts), especially when they occur in low density. We conclude that natural selection may promote different strategies of roost finding in relation to habitat conditions and cognitive skills of animals.

  16. Modelling sensory limitation: the role of tree selection, memory and information transfer in bats' roost searching strategies.

    Directory of Open Access Journals (Sweden)

    Ireneusz Ruczyński

    Full Text Available Sensory limitation plays an important role in the evolution of animal behaviour. Animals have to find objects of interest (e.g. food, shelters, predators. When sensory abilities are strongly limited, animals adjust their behaviour to maximize chances for success. Bats are nocturnal, live in complex environments, are capable of flight and must confront numerous perceptual challenges (e.g. limited sensory range, interfering clutter echoes. This makes them an excellent model for studying the role of compensating behaviours to decrease costs of finding resources. Cavity roosting bats are especially interesting because the availability of tree cavities is often limited, and their quality is vital for bats during the breeding season. From a bat's sensory point of view, cavities are difficult to detect and finding them requires time and energy. However, tree cavities are also long lasting, allowing information transfer among conspecifics. Here, we use a simple simulation model to explore the benefits of tree selection, memory and eavesdropping (compensation behaviours to searches for tree cavities by bats with short and long perception range. Our model suggests that memory and correct discrimination of tree suitability are the basic strategies decreasing the cost of roost finding, whereas perceptual range plays a minor role in this process. Additionally, eavesdropping constitutes a buffer that reduces the costs of finding new resources (such as roosts, especially when they occur in low density. We conclude that natural selection may promote different strategies of roost finding in relation to habitat conditions and cognitive skills of animals.

  17. Surgical strategies in the treatment of chronic pancreatitis: An updated systematic review and meta-analysis of randomized controlled trials.

    Science.gov (United States)

    Zhao, Xin; Cui, Naiqiang; Wang, Ximo; Cui, Yunfeng

    2017-03-01

    Chronic pancreatitis (CP) is a common and frequently occurring disease. Pancreaticoduodenectomy (PD), pylorus-preserving pancreaticoduodenectomy (PPPD), and duodenum-preserving pancreatic head resection (DPPHR) are important treatment options for patients with chronic pancreatitis. The Beger and Frey procedures are 2 main duodenum-preserving techniques in duodenum-preserving pancreatic head resection (DPPHR) strategies. We conducted this systematic review and meta-analysis to compare the clinical efficacy of DPPHR versus PD, the Beger procedure versus PD, the Frey procedure versus PD, and the Beger procedure versus the Frey procedure in the treatment of pancreatitis. The optimal surgical option for chronic pancreatitis is still under debate. The aim of this systematic review and meta-analysis was to evaluate the clinical efficacy of different surgical strategies for chronic pancreatitis. Five databases (PubMed, Medline, SinoMed, Embase, and Cochrane Library) were searched with the limitations of human subjects and randomized controlled trials (RCTs) text. Data were extracted by 2 of the coauthors independently and analyzed using the RevMan statistical software, version 5.3. Weighted mean differences (WMDs), risk ratios (RRs), and 95% confidence intervals (CIs) were calculated. Cochrane Collaboration's Risk of Bias Tool was used to assess the risk of bias. Seven studies involving a total of 385 patients who underwent the surgical treatments were assessed. The methodological quality of the trials ranged from low to moderate and included PD (n = 134) and DPPHR (n = 251 [Beger procedure = 100; Frey procedure = 109; Beger or Frey procedure = 42]). There were no significant differences between DPPHR and PD in post-operation mortality (RR = 2.89, 95% CI = 0.31-26.87, P = 0.36), pain relief (RR = 1.09, 95% CI = 0.94-1.25, P = 0.26), exocrine insufficiency (follow-up time > 60 months: RR = 0.91, 95% CI = 0.72-1.15, P

  18. Best strategies to implement clinical pathways in an emergency department setting: study protocol for a cluster randomized controlled trial.

    Science.gov (United States)

    Jabbour, Mona; Curran, Janet; Scott, Shannon D; Guttman, Astrid; Rotter, Thomas; Ducharme, Francine M; Lougheed, M Diane; McNaughton-Filion, M Louise; Newton, Amanda; Shafir, Mark; Paprica, Alison; Klassen, Terry; Taljaard, Monica; Grimshaw, Jeremy; Johnson, David W

    2013-05-22

    The clinical pathway is a tool that operationalizes best evidence recommendations and clinical practice guidelines in an accessible format for 'point of care' management by multidisciplinary health teams in hospital settings. While high-quality, expert-developed clinical pathways have many potential benefits, their impact has been limited by variable implementation strategies and suboptimal research designs. Best strategies for implementing pathways into hospital settings remain unknown. This study will seek to develop and comprehensively evaluate best strategies for effective local implementation of externally developed expert clinical pathways. We will develop a theory-based and knowledge user-informed intervention strategy to implement two pediatric clinical pathways: asthma and gastroenteritis. Using a balanced incomplete block design, we will randomize 16 community emergency departments to receive the intervention for one clinical pathway and serve as control for the alternate clinical pathway, thus conducting two cluster randomized controlled trials to evaluate this implementation intervention. A minimization procedure will be used to randomize sites. Intervention sites will receive a tailored strategy to support full clinical pathway implementation. We will evaluate implementation strategy effectiveness through measurement of relevant process and clinical outcomes. The primary process outcome will be the presence of an appropriately completed clinical pathway on the chart for relevant patients. Primary clinical outcomes for each clinical pathway include the following: Asthma--the proportion of asthmatic patients treated appropriately with corticosteroids in the emergency department and at discharge; and Gastroenteritis--the proportion of relevant patients appropriately treated with oral rehydration therapy. Data sources include chart audits, administrative databases, environmental scans, and qualitative interviews. We will also conduct an overall process

  19. Strategies to reduce safety violations for working from heights in construction companies: study protocol for a randomized controlled trial.

    Science.gov (United States)

    van der Molen, Henk F; Frings-Dresen, Monique H W

    2014-05-31

    Safety measures should be applied to reduce work-related fatal and non-fatal fall injuries. However, according to the labor inspectorate, more than 80% of Dutch construction sites violate safety regulations for working from heights. To increase compliance with safety regulations, employers and workers have to select, implement and monitor safety measures. To facilitate this behavioral change, stimulating knowledge awareness and personalized feedback are frequently advocated behavior change techniques. For this study, two behavior change strategies have been developed in addition to the announcement of safety inspections by the labor inspectorate. These strategies consist of 1) face-to-face contacts with safety consultants and 2) direct mail with access to internet facilities. The objective of this study is to evaluate the effectiveness of these two strategies on the safety violations for working from heights, the process and the cost measures. This study is a block randomized intervention trial in 27 cities to establish the effects of the face-to-face guidance strategy (N = 9), a direct mailing strategy (N = 9) and a control condition of no guidance (N = 9) on safety violations to record by labor inspectors after three months. A process evaluation for both strategies will be performed to determine program implementation (reach, dose delivered and dose received), satisfaction, knowledge and perceived safety behavior. A cost analysis will be performed to establish the financial costs for both strategies. The present study is in accordance with the CONSORT statement. This study increases insight into performing practice-based randomized controlled trials. The outcome will help to evaluate the effect of two guidance strategies on safety violations. If these strategies are effective, implementation of these strategies through the national institute of safety and health or labor inspectorate can take place to guide construction companies in complying with

  20. Optimal search behavior and classic foraging theory

    International Nuclear Information System (INIS)

    Bartumeus, F; Catalan, J

    2009-01-01

    Random walk methods and diffusion theory pervaded ecological sciences as methods to analyze and describe animal movement. Consequently, statistical physics was mostly seen as a toolbox rather than as a conceptual framework that could contribute to theory on evolutionary biology and ecology. However, the existence of mechanistic relationships and feedbacks between behavioral processes and statistical patterns of movement suggests that, beyond movement quantification, statistical physics may prove to be an adequate framework to understand animal behavior across scales from an ecological and evolutionary perspective. Recently developed random search theory has served to critically re-evaluate classic ecological questions on animal foraging. For instance, during the last few years, there has been a growing debate on whether search behavior can include traits that improve success by optimizing random (stochastic) searches. Here, we stress the need to bring together the general encounter problem within foraging theory, as a mean for making progress in the biological understanding of random searching. By sketching the assumptions of optimal foraging theory (OFT) and by summarizing recent results on random search strategies, we pinpoint ways to extend classic OFT, and integrate the study of search strategies and its main results into the more general theory of optimal foraging.

  1. Personalized versus standardized dosing strategies for the treatment of childhood amblyopia: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Moseley, Merrick J; Wallace, Michael P; Stephens, David A; Fielder, Alistair R; Smith, Laura C; Stewart, Catherine E

    2015-04-25

    Amblyopia is the commonest visual disorder of childhood in Western societies, affecting, predominantly, spatial visual function. Treatment typically requires a period of refractive correction ('optical treatment') followed by occlusion: covering the nonamblyopic eye with a fabric patch for varying daily durations. Recent studies have provided insight into the optimal amount of patching ('dose'), leading to the adoption of standardized dosing strategies, which, though an advance on previous ad-hoc regimens, take little account of individual patient characteristics. This trial compares the effectiveness of a standardized dosing strategy (that is, a fixed daily occlusion dose based on disease severity) with a personalized dosing strategy (derived from known treatment dose-response functions), in which an initially prescribed occlusion dose is modulated, in a systematic manner, dependent on treatment compliance. A total of 120 children aged between 3 and 8 years of age diagnosed with amblyopia in association with either anisometropia or strabismus, or both, will be randomized to receive either a standardized or a personalized occlusion dose regimen. To avoid confounding by the known benefits of refractive correction, participants will not be randomized until they have completed an optical treatment phase. The primary study objective is to determine whether, at trial endpoint, participants receiving a personalized dosing strategy require fewer hours of occlusion than those in receipt of a standardized dosing strategy. Secondary objectives are to quantify the relationship between observed changes in visual acuity (logMAR, logarithm of the Minimum Angle of Resolution) with age, amblyopia type, and severity of amblyopic visual acuity deficit. This is the first randomized controlled trial of occlusion therapy for amblyopia to compare a treatment arm representative of current best practice with an arm representative of an entirely novel treatment regimen based on statistical

  2. Biomarker-based strategy for early discontinuation of empirical antifungal treatment in critically ill patients: a randomized controlled trial.

    Science.gov (United States)

    Rouzé, Anahita; Loridant, Séverine; Poissy, Julien; Dervaux, Benoit; Sendid, Boualem; Cornu, Marjorie; Nseir, Saad

    2017-11-01

    The aim of this study was to determine the impact of a biomarker-based strategy on early discontinuation of empirical antifungal treatment. Prospective randomized controlled single-center unblinded study, performed in a mixed ICU. A total of 110 patients were randomly assigned to a strategy in which empirical antifungal treatment duration was determined by (1,3)-β-D-glucan, mannan, and anti-mannan serum assays, performed on day 0 and day 4; or to a routine care strategy, based on international guidelines, which recommend 14 days of treatment. In the biomarker group, early stop recommendation was determined using an algorithm based on the results of biomarkers. The primary outcome was the percentage of survivors discontinuing empirical antifungal treatment early, defined as a discontinuation strictly before day 7. A total of 109 patients were analyzed (one patient withdraw consent). Empirical antifungal treatment was discontinued early in 29 out of 54 patients in the biomarker strategy group, compared with one patient out of 55 in the routine strategy group [54% vs 2%, p strategy compared with routine strategy [median (IQR) 6 (4-13) vs 13 (12-14) days, p strategy increased the percentage of early discontinuation of empirical antifungal treatment among critically ill patients with suspected invasive Candida infection. These results confirm previous findings suggesting that early discontinuation of empirical antifungal treatment had no negative impact on outcome. However, further studies are needed to confirm the safety of this strategy. This trial was registered at ClinicalTrials.gov, NCT02154178.

  3. Do walking strategies to increase physical activity reduce reported sitting in workplaces: a randomized control trial

    Directory of Open Access Journals (Sweden)

    Burton Nicola W

    2009-07-01

    Full Text Available Abstract Background Interventions designed to increase workplace physical activity may not automatically reduce high volumes of sitting, a behaviour independently linked to chronic diseases such as obesity and type II diabetes. This study compared the impact two different walking strategies had on step counts and reported sitting times. Methods Participants were white-collar university employees (n = 179; age 41.3 ± 10.1 years; 141 women, who volunteered and undertook a standardised ten-week intervention at three sites. Pre-intervention step counts (Yamax SW-200 and self-reported sitting times were measured over five consecutive workdays. Using pre-intervention step counts, employees at each site were randomly allocated to a control group (n = 60; maintain normal behaviour, a route-based walking group (n = 60; at least 10 minutes sustained walking each workday or an incidental walking group (n = 59; walking in workday tasks. Workday step counts and reported sitting times were re-assessed at the beginning, mid- and endpoint of intervention and group mean± SD steps/day and reported sitting times for pre-intervention and intervention measurement points compared using a mixed factorial ANOVA; paired sample-t-tests were used for follow-up, simple effect analyses. Results A significant interactive effect (F = 3.5; p t = 3.9, p t = 2.5, p Conclusion Compared to controls, both route and incidental walking increased physical activity in white-collar employees. Our data suggests that workplace walking, particularly through incidental movement, also has the potential to decrease employee sitting times, but there is a need for on-going research using concurrent and objective measures of sitting, standing and walking.

  4. Testing the implementation and sustainment facilitation (ISF) strategy as an effective adjunct to the Addiction Technology Transfer Center (ATTC) strategy: study protocol for a cluster randomized trial.

    Science.gov (United States)

    Garner, Bryan R; Zehner, Mark; Roosa, Mathew R; Martino, Steve; Gotham, Heather J; Ball, Elizabeth L; Stilen, Patricia; Speck, Kathryn; Vandersloot, Denna; Rieckmann, Traci R; Chaple, Michael; Martin, Erika G; Kaiser, David; Ford, James H

    2017-11-17

    Improving the extent to which evidence-based practices (EBPs)-treatments that have been empirically shown to be efficacious or effective-are integrated within routine practice is a well-documented challenge across numerous areas of health. In 2014, the National Institute on Drug Abuse funded a type 2 effectiveness-implementation hybrid trial titled the substance abuse treatment to HIV Care (SAT2HIV) Project. Aim 1 of the SAT2HIV Project tests the effectiveness of a motivational interviewing-based brief intervention (MIBI) for substance use as an adjunct to usual care within AIDS service organizations (ASOs) as part of its MIBI Experiment. Aim 2 of the SAT2HIV Project tests the effectiveness of implementation and sustainment facilitation (ISF) as an adjunct to the Addiction Technology Transfer Center (ATTC) model for training staff in motivational interviewing as part of its ISF Experiment. The current paper describes the study protocol for the ISF Experiment. Using a cluster randomized design, case management and leadership staff from 39 ASOs across the United States were randomized to receive either the ATTC strategy (control condition) or the ATTC + ISF strategy (experimental condition). The ATTC strategy is staff-focused and includes 10 discrete strategies (e.g., provide centralized technical assistance, conduct educational meetings, provide ongoing consultation). The ISF strategy is organization-focused and includes seven discrete strategies (e.g., use an implementation advisor, organize implementation team meetings, conduct cyclical small tests of change). Building upon the exploration-preparation-implementation-sustainment (EPIS) framework, the effectiveness of the ISF strategy is examined via three staff-level measures: (1) time-to-proficiency (i.e., preparation phase outcome), (2) implementation effectiveness (i.e., implementation phase outcome), and (3) level of sustainment (i.e., sustainment phase outcome). Although not without limitations, the ISF

  5. Testing the implementation and sustainment facilitation (ISF strategy as an effective adjunct to the Addiction Technology Transfer Center (ATTC strategy: study protocol for a cluster randomized trial

    Directory of Open Access Journals (Sweden)

    Bryan R. Garner

    2017-11-01

    Full Text Available Abstract Background Improving the extent to which evidence-based practices (EBPs—treatments that have been empirically shown to be efficacious or effective—are integrated within routine practice is a well-documented challenge across numerous areas of health. In 2014, the National Institute on Drug Abuse funded a type 2 effectiveness–implementation hybrid trial titled the substance abuse treatment to HIV Care (SAT2HIV Project. Aim 1 of the SAT2HIV Project tests the effectiveness of a motivational interviewing-based brief intervention (MIBI for substance use as an adjunct to usual care within AIDS service organizations (ASOs as part of its MIBI Experiment. Aim 2 of the SAT2HIV Project tests the effectiveness of implementation and sustainment facilitation (ISF as an adjunct to the Addiction Technology Transfer Center (ATTC model for training staff in motivational interviewing as part of its ISF Experiment. The current paper describes the study protocol for the ISF Experiment. Methods Using a cluster randomized design, case management and leadership staff from 39 ASOs across the United States were randomized to receive either the ATTC strategy (control condition or the ATTC + ISF strategy (experimental condition. The ATTC strategy is staff-focused and includes 10 discrete strategies (e.g., provide centralized technical assistance, conduct educational meetings, provide ongoing consultation. The ISF strategy is organization-focused and includes seven discrete strategies (e.g., use an implementation advisor, organize implementation team meetings, conduct cyclical small tests of change. Building upon the exploration–preparation–implementation–sustainment (EPIS framework, the effectiveness of the ISF strategy is examined via three staff-level measures: (1 time-to-proficiency (i.e., preparation phase outcome, (2 implementation effectiveness (i.e., implementation phase outcome, and (3 level of sustainment (i.e., sustainment phase outcome

  6. A Study on Information Search and Commitment Strategies on Web Environment and Internet Usage Self-Efficacy Beliefs of University Students'

    Science.gov (United States)

    Geçer, Aynur Kolburan

    2014-01-01

    This study addresses university students' information search and commitment strategies on web environment and internet usage self-efficacy beliefs in terms of such variables as gender, department, grade level and frequency of internet use; and whether there is a significant relation between these beliefs. Descriptive method was used in the study.…

  7. Students' Scientific Epistemic Beliefs, Online Evaluative Standards, and Online Searching Strategies for Science Information: The Moderating Role of Cognitive Load Experience

    Science.gov (United States)

    Hsieh, Ya-Hui; Tsai, Chin-Chung

    2014-01-01

    The purpose of this study is to examine the moderating role of cognitive load experience between students' scientific epistemic beliefs and information commitments, which refer to online evaluative standards and online searching strategies. A total of 344 science-related major students participated in this study. Three questionnaires were…

  8. Analysis of Students' Online Information Searching Strategies, Exposure to Internet Information Pollution and Cognitive Absorption Levels Based on Various Variables

    Science.gov (United States)

    Kurt, Adile Askim; Emiroglu, Bülent Gürsel

    2018-01-01

    The objective of the present study was to examine students' online information searching strategies, their cognitive absorption levels and the information pollution levels on the Internet based on different variables and to determine the correlation between these variables. The study was designed with the survey model, the study group included 198…

  9. Face Recognition and Visual Search Strategies in Autism Spectrum Disorders: Amending and Extending a Recent Review by Weigelt et al.

    Directory of Open Access Journals (Sweden)

    Julia Tang

    Full Text Available The purpose of this review was to build upon a recent review by Weigelt et al. which examined visual search strategies and face identification between individuals with autism spectrum disorders (ASD and typically developing peers. Seven databases, CINAHL Plus, EMBASE, ERIC, Medline, Proquest, PsychInfo and PubMed were used to locate published scientific studies matching our inclusion criteria. A total of 28 articles not included in Weigelt et al. met criteria for inclusion into this systematic review. Of these 28 studies, 16 were available and met criteria at the time of the previous review, but were mistakenly excluded; and twelve were recently published. Weigelt et al. found quantitative, but not qualitative, differences in face identification in individuals with ASD. In contrast, the current systematic review found both qualitative and quantitative differences in face identification between individuals with and without ASD. There is a large inconsistency in findings across the eye tracking and neurobiological studies reviewed. Recommendations for future research in face recognition in ASD were discussed.

  10. Using Direct Policy Search to Identify Robust Strategies in Adapting to Uncertain Sea Level Rise and Storm Surge

    Science.gov (United States)

    Garner, G. G.; Keller, K.

    2017-12-01

    Sea-level rise poses considerable risks to coastal communities, ecosystems, and infrastructure. Decision makers are faced with deeply uncertain sea-level projections when designing a strategy for coastal adaptation. The traditional methods have provided tremendous insight into this decision problem, but are often silent on tradeoffs as well as the effects of tail-area events and of potential future learning. Here we reformulate a simple sea-level rise adaptation model to address these concerns. We show that Direct Policy Search yields improved solution quality, with respect to Pareto-dominance in the objectives, over the traditional approach under uncertain sea-level rise projections and storm surge. Additionally, the new formulation produces high quality solutions with less computational demands than the traditional approach. Our results illustrate the utility of multi-objective adaptive formulations for the example of coastal adaptation, the value of information provided by observations, and point to wider-ranging application in climate change adaptation decision problems.

  11. Using pilot data to size a two-arm randomized trial to find a nearly optimal personalized treatment strategy.

    Science.gov (United States)

    Laber, Eric B; Zhao, Ying-Qi; Regh, Todd; Davidian, Marie; Tsiatis, Anastasios; Stanford, Joseph B; Zeng, Donglin; Song, Rui; Kosorok, Michael R

    2016-04-15

    A personalized treatment strategy formalizes evidence-based treatment selection by mapping patient information to a recommended treatment. Personalized treatment strategies can produce better patient outcomes while reducing cost and treatment burden. Thus, among clinical and intervention scientists, there is a growing interest in conducting randomized clinical trials when one of the primary aims is estimation of a personalized treatment strategy. However, at present, there are no appropriate sample size formulae to assist in the design of such a trial. Furthermore, because the sampling distribution of the estimated outcome under an estimated optimal treatment strategy can be highly sensitive to small perturbations in the underlying generative model, sample size calculations based on standard (uncorrected) asymptotic approximations or computer simulations may not be reliable. We offer a simple and robust method for powering a single stage, two-armed randomized clinical trial when the primary aim is estimating the optimal single stage personalized treatment strategy. The proposed method is based on inverting a plugin projection confidence interval and is thereby regular and robust to small perturbations of the underlying generative model. The proposed method requires elicitation of two clinically meaningful parameters from clinical scientists and uses data from a small pilot study to estimate nuisance parameters, which are not easily elicited. The method performs well in simulated experiments and is illustrated using data from a pilot study of time to conception and fertility awareness. Copyright © 2015 John Wiley & Sons, Ltd.

  12. Use of recommended search strategies in systematic reviews and the impact of librarian involvement: a cross-sectional survey of recent authors.

    Science.gov (United States)

    Koffel, Jonathan B

    2015-01-01

    Previous research looking at published systematic reviews has shown that their search strategies are often suboptimal and that librarian involvement, though recommended, is low. Confidence in the results, however, is limited due to poor reporting of search strategies the published articles. To more accurately measure the use of recommended search methods in systematic reviews, the levels of librarian involvement, and whether librarian involvement predicts the use of recommended methods. A survey was sent to all authors of English-language systematic reviews indexed in the Database of Abstracts of Reviews of Effects (DARE) from January 2012 through January 2014. The survey asked about their use of search methods recommended by the Institute of Medicine, Cochrane Collaboration, and the Agency for Healthcare Research and Quality and if and how a librarian was involved in the systematic review. Rates of use of recommended methods and librarian involvement were summarized. The impact of librarian involvement on use of recommended methods was examined using a multivariate logistic regression. 1560 authors completed the survey. Use of recommended search methods ranged widely from 98% for use of keywords to 9% for registration in PROSPERO and were generally higher than in previous studies. 51% of studies involved a librarian, but only 64% acknowledge their assistance. Librarian involvement was significantly associated with the use of 65% of recommended search methods after controlling for other potential predictors. Odds ratios ranged from 1.36 (95% CI 1.06 to 1.75) for including multiple languages to 3.07 (95% CI 2.06 to 4.58) for using controlled vocabulary. Use of recommended search strategies is higher than previously reported, but many methods are still under-utilized. Librarian involvement predicts the use of most methods, but their involvement is under-reported within the published article.

  13. Study protocol: Couples Partnering for Lipid Enhancing Strategies (CouPLES – a randomized, controlled trial

    Directory of Open Access Journals (Sweden)

    Weinberger Morris

    2009-02-01

    Full Text Available Abstract Background Almost 50% of Americans have elevated low-density lipoprotein cholesterol (LDL-C. The behaviors required to lower LDL-C levels may be difficult to adhere to if they are inconsistent with spouses' health practices, and, alternatively, may be enhanced by enlisting support from the spouse. This trial extends previous trials by requiring spouse enrollment, teaching spouses how to provide emotional and instrumental support, allowing patients to decide which component of the intervention they would like to receive, and having patients determine their own goals and action plans. Methods Veteran outpatients with above-goal LDL-C (N = 250 and their spouses are randomized, as a couple, to receive printed education materials only or the materials plus an 11-month, nurse-delivered, telephone-based intervention. The intervention contains four modules: medication adherence, diet, exercise, and patient-physician communication. Patients decide which modules they complete and in which order; modules may be repeated or omitted. Telephone calls are to patients and spouses separately and occur monthly. During each patient telephone call, patients' progress is reviewed, and patients create goals and action plans for the upcoming month. During spouse telephone calls, which occur within one week of patient calls, spouses are informed of patients' goals and action plans and devise strategies to increase emotional and instrumental support. The primary outcome is patients' LDL-C, measured at baseline, 6 months, and 11 months. Linear mixed models will be used to test the primary hypothesis that an 11-month, telephone-based patient-spouse intervention will result in a greater reduction in LDL-C as compared to printed education materials. Various process measures, including social support, self-efficacy, medication adherence, dietary behavior, and exercise, are also assessed to explain any change, or lack thereof, in LDL-C. Discussion Given the social

  14. A mild ovarian stimulation strategy in women with poor ovarian reserve undergoing IVF: a multicenter randomized non-inferiority trial.

    Science.gov (United States)

    Youssef, M A; van Wely, M; Al-Inany, H; Madani, T; Jahangiri, N; Khodabakhshi, S; Alhalabi, M; Akhondi, M; Ansaripour, S; Tokhmechy, R; Zarandi, L; Rizk, A; El-Mohamedy, M; Shaeer, E; Khattab, M; Mochtar, M H; van der Veen, F

    2017-01-01

    In subfertile women with poor ovarian reserve undergoing IVF does a mild ovarian stimulation strategy lead to comparable ongoing pregnancy rates in comparison to a conventional ovarian stimulation strategy? A mild ovarian stimulation strategy in women with poor ovarian reserve undergoing IVF leads to similar ongoing pregnancy rates as a conventional ovarian stimulation strategy. Women diagnosed with poor ovarian reserve are treated with a conventional ovarian stimulation strategy consisting of high-dose gonadotropins and pituitary downregulation with a long mid-luteal start GnRH-agonist protocol. Previous studies comparing a conventional strategy with a mild ovarian stimulation strategy consisting of low-dose gonadotropins and pituitary downregulation with a GnRH-antagonist have been under powered and their effectiveness is inconclusive. This open label multicenter randomized trial was designed to compare one cycle of a mild ovarian stimulation strategy consisting of low-dose gonadotropins (150 IU FSH) and pituitary downregulation with a GnRH-antagonist to one cycle of a conventional ovarian stimulation strategy consisting of high-dose gonadotropins (450 IU HMG) and pituitary downregulation with a long mid-luteal GnRH-agonist in women of advanced maternal age and/or women with poor ovarian reserve undergoing IVF between May 2011 and April 2014. Couples seeking infertility treatment were eligible if they fulfilled the following inclusion criteria: female age ≥35 years, a raised basal FSH level >10 IU/ml irrespective of age, a low antral follicular count of ≤5 follicles or poor ovarian response or cycle cancellation during a previous IVF cycle irrespective of age. The primary outcome was ongoing pregnancy rate per woman randomized. Analyses were on an intention-to-treat basis. We randomly assigned 195 women to the mild ovarian stimulation strategy and 199 women to the conventional ovarian stimulation strategy. Ongoing pregnancy rate was 12.8% (25/195) for mild

  15. A Fuzzy-Logic Power Management Strategy Based on Markov Random Prediction for Hybrid Energy Storage Systems

    Directory of Open Access Journals (Sweden)

    Yanzi Wang

    2016-01-01

    Full Text Available Over the last few years; issues regarding the use of hybrid energy storage systems (HESSs in hybrid electric vehicles have been highlighted by the industry and in academic fields. This paper proposes a fuzzy-logic power management strategy based on Markov random prediction for an active parallel battery-UC HESS. The proposed power management strategy; the inputs for which are the vehicle speed; the current electric power demand and the predicted electric power demand; is used to distribute the electrical power between the battery bank and the UC bank. In this way; the battery bank power is limited to a certain range; and the peak and average charge/discharge power of the battery bank and overall loss incurred by the whole HESS are also reduced. Simulations and scaled-down experimental platforms are constructed to verify the proposed power management strategy. The simulations and experimental results demonstrate the advantages; feasibility and effectiveness of the fuzzy-logic power management strategy based on Markov random prediction.

  16. Principles and strategies for monitoring data collection integrity in a multi-site randomized clinical trial of a behavioral intervention.

    Science.gov (United States)

    Phillips-Salimi, Celeste R; Donovan Stickler, Molly A; Stegenga, Kristin; Lee, Melissa; Haase, Joan E

    2011-08-01

    Although treatment fidelity strategies for enhancing the integrity of behavioral interventions have been well described, little has been written about monitoring data collection integrity. This article describes the principles and strategies developed to monitor data collection integrity of the "Stories and Music for Adolescent/Young Adult Resilience During Transplant" study (R01NR008583, U10CA098543, and U10CA095861)-a multi-site Children's Oncology Group randomized clinical trial of a music therapy intervention for adolescents and young adults undergoing stem cell transplant. The principles and strategies outlined in this article provide one model for development and evaluation of a data collection integrity monitoring plan for behavioral interventions that may be adapted by investigators and may be useful to funding agencies and grant application reviewers in evaluating proposals. Copyright © 2011 Wiley Periodicals, Inc.

  17. Beyond MEDLINE for literature searches.

    Science.gov (United States)

    Conn, Vicki S; Isaramalai, Sang-arun; Rath, Sabyasachi; Jantarakupt, Peeranuch; Wadhawan, Rohini; Dash, Yashodhara

    2003-01-01

    To describe strategies for a comprehensive literature search. MEDLINE searches result in limited numbers of studies that are often biased toward statistically significant findings. Diversified search strategies are needed. Empirical evidence about the recall and precision of diverse search strategies is presented. Challenges and strengths of each search strategy are identified. Search strategies vary in recall and precision. Often sensitivity and specificity are inversely related. Valuable search strategies include examination of multiple diverse computerized databases, ancestry searches, citation index searches, examination of research registries, journal hand searching, contact with the "invisible college," examination of abstracts, Internet searches, and contact with sources of synthesized information. Extending searches beyond MEDLINE enables researchers to conduct more systematic comprehensive searches.

  18. Search predicts and changes patience in intertemporal choice

    Science.gov (United States)

    Johnson, Eric J.

    2017-01-01

    Intertemporal choice impacts many important outcomes, such as decisions about health, education, wealth, and the environment. However, the psychological processes underlying decisions involving outcomes at different points in time remain unclear, limiting opportunities to intervene and improve people’s patience. This research examines information-search strategies used during intertemporal choice and their impact on decisions. In experiment 1, we demonstrate that search strategies vary substantially across individuals. We subsequently identify two distinct search strategies across individuals. Comparative searchers, who compare features across options, discount future options less and are more susceptible to acceleration versus delay framing than integrative searchers, who integrate the features of an option. Experiment 2 manipulates search using an unobtrusive method to establish a causal relationship between strategy and choice, randomly assigning participants to conditions promoting either comparative or integrative search. Again, comparative search promotes greater patience than integrative search. Additionally, when participants adopt a comparative search strategy, they also exhibit greater effects of acceleration versus delay framing. Although most participants reported that the manipulation did not change their behavior, promoting comparative search decreased discounting of future rewards substantially and speeded patient choices. These findings highlight the central role that heterogeneity in psychological processes plays in shaping intertemporal choice. Importantly, these results indicate that theories that ignore variability in search strategies may be inadvertently aggregating over different subpopulations that use very different processes. The findings also inform interventions in choice architecture to increase patience and improve consumer welfare. PMID:29078303

  19. Search predicts and changes patience in intertemporal choice.

    Science.gov (United States)

    Reeck, Crystal; Wall, Daniel; Johnson, Eric J

    2017-11-07

    Intertemporal choice impacts many important outcomes, such as decisions about health, education, wealth, and the environment. However, the psychological processes underlying decisions involving outcomes at different points in time remain unclear, limiting opportunities to intervene and improve people's patience. This research examines information-search strategies used during intertemporal choice and their impact on decisions. In experiment 1, we demonstrate that search strategies vary substantially across individuals. We subsequently identify two distinct search strategies across individuals. Comparative searchers, who compare features across options, discount future options less and are more susceptible to acceleration versus delay framing than integrative searchers, who integrate the features of an option. Experiment 2 manipulates search using an unobtrusive method to establish a causal relationship between strategy and choice, randomly assigning participants to conditions promoting either comparative or integrative search. Again, comparative search promotes greater patience than integrative search. Additionally, when participants adopt a comparative search strategy, they also exhibit greater effects of acceleration versus delay framing. Although most participants reported that the manipulation did not change their behavior, promoting comparative search decreased discounting of future rewards substantially and speeded patient choices. These findings highlight the central role that heterogeneity in psychological processes plays in shaping intertemporal choice. Importantly, these results indicate that theories that ignore variability in search strategies may be inadvertently aggregating over different subpopulations that use very different processes. The findings also inform interventions in choice architecture to increase patience and improve consumer welfare. Copyright © 2017 the Author(s). Published by PNAS.

  20. A new combined strategy to implement a community occupational therapy intervention: designing a cluster randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Adang Eddy

    2011-03-01

    Full Text Available Abstract Background Even effective interventions for people with dementia and their caregivers require specific implementation efforts. A pilot study showed that the highly effective community occupational therapy in dementia (COTiD program was not implemented optimally due to various barriers. To decrease these barriers and make implementation of the program more effective a combined implementation (CI strategy was developed. In our study we will compare the effectiveness of this CI strategy with the usual educational (ED strategy. Methods In this cluster randomized, single-blinded, controlled trial, each cluster consists of at least two occupational therapists, a manager, and a physician working at Dutch healthcare organizations that deliver community occupational therapy. Forty-five clusters, stratified by healthcare setting (nursing home, hospital, mental health service, have been allocated randomly to either the intervention group (CI strategy or the control group (ED strategy. The study population consists of the professionals included in each cluster and community-dwelling people with dementia and their caregivers. The primary outcome measures are the use of community OT, the adherence of OTs to the COTiD program, and the cost effectiveness of implementing the COTiD program in outpatient care. Secondary outcome measures are patient and caregiver outcomes and knowledge of managers, physicians and OTs about the COTiD program. Discussion Implementation research is fairly new in the field of occupational therapy, making this a unique study. This study does not only evaluate the effects of the CI-strategy on professionals, but also the effects of professionals' degree of implementation on client and caregiver outcomes. Clinical trials registration NCT01117285

  1. Efficacy of strategy training in left hemisphere stroke patients with apraxia: a randomized clinical trial.

    NARCIS (Netherlands)

    Dekker, J.; Donkervoort, M.; Stehman, F.C.; Deelman, B.G.

    2001-01-01

    The objective of the present study was to determine in a controlled study the efficacy of strategy training in left hemisphere stroke patients with apraxia. 113 Left hemisphere assigned to two treatment groups: i) strategy training integrated into usual occupational therapy and ii) usual

  2. Production planning and backup sourcing strategy of a buyer-dominant supply chain with random yield and demand

    Science.gov (United States)

    Chen, Kebing; Xiao, Tiaojun

    2015-11-01

    This paper studies the backup sourcing strategy of the buyer and the production planning of the supplier in presence of both random yield and random demand. Since the production is susceptible to the randomness of yield beyond the control of the supplier, the buyer may access to a backup sourcing option for the finished items. We analyse the value of backup sourcing for both the decentralised and centralised channels. Backup sourcing strategy of the buyer may lower the supply chain's performance. We show that the order quantity of the buyer does not change the stocking factor of the supplier's input. Meanwhile, compared with the centralised operation, the decentralised operation is more dependent on the backup sourcing to reduce supply shortage of the contracting supplier. From the channel's perspective, an incentive scheme is developed to facilitate the coordination of both the buyer and the contracting supplier, we show that the proposed option contract can allow the supply chain members to share the respective risks involved in the production and selling processes. Finally, we also provide qualitative insights based on numerical examples of the centralised and decentralised solutions.

  3. A cost-effective approach to the development of printed materials: a randomized controlled trial of three strategies.

    Science.gov (United States)

    Paul, C L; Redman, S; Sanson-Fisher, R W

    2004-12-01

    Printed materials have been a primary mode of communication in public health education. Three major approaches to the development of these materials--the application of characteristics identified in the literature, behavioral strategies and marketing strategies--have major implications for both the effectiveness and cost of materials. However, little attention has been directed towards the cost-effectiveness of such approaches. In the present study, three pamphlets were developed using successive addition of each approach: first literature characteristics only ('C' pamphlet), then behavioral strategies ('C + B' pamphlet) and then marketing strategies ('C + B + M' pamphlet). Each pamphlet encouraged women to join a Pap Test Reminder Service (PTRS). Each pamphlet was mailed to a randomly selected sample of 2700 women aged 50-69 years. Registrations with the PTRS were monitored and 420 women in each pamphlet group were surveyed by telephone. It was reported that the 'C + B' and 'C + B + M' pamphlets were significantly more effective than the 'C' pamphlet. The 'C + B' pamphlet was the most cost-effective of the three pamphlets. There were no significant differences between any of the pamphlet groups on acceptability, knowledge or attitudes. It was suggested that the inclusion of behavioral strategies is likely to be a cost-effective approach to the development of printed health education materials.

  4. Assessment of strategies for switching patients from olanzapine to risperidone: A randomized, open-label, rater-blinded study

    Directory of Open Access Journals (Sweden)

    Berry Sally A

    2008-06-01

    Full Text Available Abstract Background In clinical practice, physicians often need to change the antipsychotic medications they give to patients because of an inadequate response or the presence of unacceptable or unsafe side effects. However, there is a lack of consensus in the field as to the optimal switching strategy for antipsychotics, especially with regards to the speed at which the dose of the previous antipsychotic should be reduced. This paper assesses the short-term results of strategies for the discontinuation of olanzapine when initiating risperidone. Methods In a 6-week, randomized, open-label, rater-blinded study, patients with schizophrenia or schizoaffective disorder, on a stable drug dose for more than 30 days at entry, who were intolerant of or exhibiting a suboptimal symptom response to more than 30 days of olanzapine treatment, were randomly assigned to the following switch strategies (common risperidone initiation scheme; varying olanzapine discontinuation: (i abrupt strategy, where olanzapine was discontinued at risperidone initiation; (ii gradual 1 strategy, where olanzapine was given at 50% entry dose for 1 week after risperidone initiation and then discontinued; or (iii gradual 2 strategy, where olanzapine was given at 100% entry dose for 1 week, then at 50% in the second week, and then discontinued. Results The study enrolled 123 patients on stable doses of olanzapine. Their mean age was 40.3 years and mean (± standard deviation (SD baseline Positive and Negative Syndrome Scale (PANSS total score of 75.6 ± 11.5. All-cause treatment discontinuation was lowest (12% in the group with the slowest olanzapine dose reduction (gradual 2 and occurred at half the discontinuation rate in the other two groups (25% in abrupt and 28% in gradual 1. The relative risk of early discontinuation was 0.77 (confidence interval 0.61–0.99 for the slowest dose reduction compared with the other two strategies. After the medication was changed, improvements at

  5. Endovascular strategy or open repair for ruptured abdominal aortic aneurysm: one-year outcomes from the IMPROVE randomized trial

    Science.gov (United States)

    Braithwaite, Bruce; Cheshire, Nicholas J.; Greenhalgh, Roger M.; Grieve, Richard; Hassan, Tajek B.; Hinchliffe, Robert; Howell, Simon; Moore, Fionna; Nicholson, Anthony A.; Soong, Chee V.; Thompson, Matt M.; Thompson, Simon G.; Ulug, Pinar; Heatley, Francine; Anjum, Aisha; Kalinowska, Gosia; Sweeting, Michael J.; Thompson, Simon G.; Gomes, Manuel; Grieve, Richard; Powell, Janet T.; Ashleigh, Ray; Gomes, Manuel; Greenhalgh, Roger M.; Grieve, Richard; Hinchliffe, Robert; Sweeting, Michael; Thompson, Matt M.; Thompson, Simon G.; Ulug, Pinar; Roberts, Ian; Bell, Peter R. F.; Cheetham, Anne; Stephany, Jenny; Warlow, Charles; Lamont, Peter; Moss, Jonathan; Tijssen, Jan; Braithwaite, Bruce; Nicholson, Anthony A.; Thompson, Matthew; Ashleigh, Ray; Thompson, Luke; Cheshire, Nicholas J.; Boyle, Jonathan R.; Serracino-Inglott, Ferdinand; Thompson, Matt M.; Hinchliffe, Robert J.; Bell, Rachel; Wilson, Noel; Bown, Matt; Dennis, Martin; Davis, Meryl; Ashleigh, Ray; Howell, Simon; Wyatt, Michael G.; Valenti, Domenico; Bachoo, Paul; Walker, Paul; MacSweeney, Shane; Davies, Jonathan N.; Rittoo, Dynesh; Parvin, Simon D.; Yusuf, Waquar; Nice, Colin; Chetter, Ian; Howard, Adam; Chong, Patrick; Bhat, Raj; McLain, David; Gordon, Andrew; Lane, Ian; Hobbs, Simon; Pillay, Woolagasen; Rowlands, Timothy; El-Tahir, Amin; Asquith, John; Cavanagh, Steve; Dubois, Luc; Forbes, Thomas L.; Ashworth, Emily; Baker, Sara; Barakat, Hashem; Brady, Claire; Brown, Joanne; Bufton, Christine; Chance, Tina; Chrisopoulou, Angela; Cockell, Marie; Croucher, Andrea; Dabee, Leela; Dewhirst, Nikki; Evans, Jo; Gibson, Andy; Gorst, Siobhan; Gough, Moira; Graves, Lynne; Griffin, Michelle; Hatfield, Josie; Hogg, Florence; Howard, Susannah; Hughes, Cían; Metcalfe, David; Lapworth, Michelle; Massey, Ian; Novick, Teresa; Owen, Gareth; Parr, Noala; Pintar, David; Spencer, Sarah; Thomson, Claire; Thunder, Orla; Wallace, Tom; Ward, Sue; Wealleans, Vera; Wilson, Lesley; Woods, Janet; Zheng, Ting

    2015-01-01

    Aims To report the longer term outcomes following either a strategy of endovascular repair first or open repair of ruptured abdominal aortic aneurysm, which are necessary for both patient and clinical decision-making. Methods and results This pragmatic multicentre (29 UK and 1 Canada) trial randomized 613 patients with a clinical diagnosis of ruptured aneurysm; 316 to an endovascular first strategy (if aortic morphology is suitable, open repair if not) and 297 to open repair. The principal 1-year outcome was mortality; secondary outcomes were re-interventions, hospital discharge, health-related quality-of-life (QoL) (EQ-5D), costs, Quality-Adjusted-Life-Years (QALYs), and cost-effectiveness [incremental net benefit (INB)]. At 1 year, all-cause mortality was 41.1% for the endovascular strategy group and 45.1% for the open repair group, odds ratio 0.85 [95% confidence interval (CI) 0.62, 1.17], P = 0.325, with similar re-intervention rates in each group. The endovascular strategy group and open repair groups had average total hospital stays of 17 and 26 days, respectively, P < 0.001. Patients surviving rupture had higher average EQ-5D utility scores in the endovascular strategy vs. open repair groups, mean differences 0.087 (95% CI 0.017, 0.158), 0.068 (95% CI −0.004, 0.140) at 3 and 12 months, respectively. There were indications that QALYs were higher and costs lower for the endovascular first strategy, combining to give an INB of £3877 (95% CI £253, £7408) or €4356 (95% CI €284, €8323). Conclusion An endovascular first strategy for management of ruptured aneurysms does not offer a survival benefit over 1 year but offers patients faster discharge with better QoL and is cost-effective. Clinical trial registration ISRCTN 48334791. PMID:25855369

  6. A randomized trial of three marketing strategies to disseminate a screening and brief alcohol intervention programme to general practitioners.

    Science.gov (United States)

    Lock, C A; Kaner, E F; Heather, N; McAvoy, B R; Gilvarry, E

    1999-09-01

    Research findings are of little benefit to patients or society if they do not reach the audience they are intended to influence. A dissemination strategy is needed to target new findings at its user group and encourage a process of consideration and adoption or rejection. To evaluate the effectiveness and cost-effectiveness of different marketing strategies for the dissemination of a screening and brief alcohol intervention (SBI) programme to general practitioners (GPs). Seven hundred and twenty-nine GPs, one per practice, from the former Northern and Yorkshire Regional Health Authority were randomly assigned to one of three marketing strategies: postal marketing (mailing a promotional brochure to GPs), telemarketing (following a script to market the programme over the telephone), and personal marketing (following the same script during face-to-face marketing at GPs' practices). GPs who took up the programme were asked if they would agree to use it. Outcome measures included the proportions of GPs who took up the programme and agreement to use it. Of the 614 GPs eligible for the study, 321 (52%) took the programme. There was a significant difference in the proportions of GPs from the three marketing strategies who took the programme (82% telemarketing, 68% personal marketing, and 22% postal marketing). Of the 315 GPs who took the programme and were eligible to use it, 128 (41%) agreed to use the programme for three months. GPs in the postal marketing group were more likely to agree to use the programme (55% postal marketing, 44% personal marketing, and 34% telemarketing). Personal marketing was the most effective overall dissemination strategy; however, economic analysis revealed that telemarketing was the most cost-effective strategy. Costs for dissemination per GP were: 13 Pounds telemarketing, 15 Pounds postal marketing, and 88 Pounds personal marketing. Telemarketing appeared to be the most cost-effective strategy for dissemination of SBI to GPs.

  7. Students' Scientific Epistemic Beliefs, Online Evaluative Standards, and Online Searching Strategies for Science Information: The Moderating Role of Cognitive Load Experience

    Science.gov (United States)

    Hsieh, Ya-Hui; Tsai, Chin-Chung

    2014-06-01

    The purpose of this study is to examine the moderating role of cognitive load experience between students' scientific epistemic beliefs and information commitments, which refer to online evaluative standards and online searching strategies. A total of 344 science-related major students participated in this study. Three questionnaires were used to ascertain the students' scientific epistemic beliefs, information commitments, and cognitive load experience. Structural equation modeling was then used to analyze the moderating effect of cognitive load, with the results revealing its significant moderating effect. The relationships between sophisticated scientific epistemic beliefs and the advanced evaluative standards used by the students were significantly stronger for low than for high cognitive load students. Moreover, considering the searching strategies that the students used, the relationships between sophisticated scientific epistemic beliefs and advanced searching strategies were also stronger for low than for high cognitive load students. However, for the high cognitive load students, only one of the sophisticated scientific epistemic belief dimensions was found to positively associate with advanced evaluative standard dimensions.

  8. Ordered Consumer Search

    OpenAIRE

    Armstrong, Mark

    2016-01-01

    The paper discusses situations in which consumers search through their options in a deliberate order, in contrast to more familiar models with random search. Topics include: network effects (consumers may be better off following the same search order as other consumers); the use of price and non-price advertising to direct search; the impact of consumers starting a new search with their previous supplier; the incentive sellers have to merge or co-locate with other sellers; and the incentive a...

  9. Optimizing Household Chlorination Marketing Strategies: A Randomized Controlled Trial on the Effect of Price and Promotion on Adoption in Haiti.

    Science.gov (United States)

    Ritter, Michael; Camille, Eveline; Velcine, Christophe; Guillaume, Rose-Kerline; Lantagne, Daniele

    2017-07-01

    Household water treatment can reduce diarrheal morbidity and mortality in developing countries, but adoption remains low and supply is often unreliable. To test effects of marketing strategies on consumers and suppliers, we randomized 1,798 households in rural Haiti and collected data on purchases of a household chlorination product for 4 months. Households received randomly selected prices ($0.11-$0.56 per chlorine bottle), and half received monthly visits from sales agents. Each $0.22 drop in price increased purchases by 0.10 bottles per household per month ( P sales agents increased purchases at mid-range prices; however, the additional revenue did not offset visit cost. Choosing the lowest price and conducting visits maximizes chlorine purchase, whereas slightly raising the retail price and not conducting visits maximizes cost recovery. For the equivalent cost, price discounts increase purchases 4.2 times as much as adding visits at the current retail price. In this context, price subsidies may be a more cost-effective use of resources than household visits, though all marketing strategies tested offer cost-effective ways to achieve incremental health impact. Decisions about pricing and promotion for health products in developing countries affect health impact, cost recovery, and cost-effectiveness, and tradeoffs between these goals should be made explicit in program design.

  10. Comparison of additional costs for several replacement strategies of randomly ageing reinforced concrete pipes

    OpenAIRE

    SCHOEFS , Franck; Aduriz , X.; Bernard , Olivier; Capra , Bruno

    2009-01-01

    International audience; One of the uses of reinforced concrete pipes (RCPs) is the distribution of aggressive water in industrial systems, for example, in water-cooling systems of nuclear power plants. Some of them carry seawater and can deteriorate with time because of internal corrosion. Because of the low O(2) content of aggressive water, slow corrosion is expected for such applications. If the RCPs are not periodically replaced, they will eventually fail. Replacement strategies for these ...

  11. A supersymmetry search strategy with single-lepton events at 13 TeV by the CMS experiment

    Energy Technology Data Exchange (ETDEWEB)

    Lobanov, Artur; Seitz, Claudia; Melzer-Pellmann, Isabell; Singh, Akshansh [DESY, Hamburg (Germany)

    2016-07-01

    We present an inclusive search for supersymmetry in the single-lepton channel with 13 TeV. To optimise the sensitivity to various new-physics topologies, we search in several exclusive categories which differ in the number of jets and b-tagged jets. We determine the background from data, exploiting the fact that the main background is located at small values of the azimuthal angle between the W-boson candidate and the charged lepton. To be less dependent on the new-physics scale, we also introduce separate search categories based on the scalar sum of the jet transverse momenta and on the scalar sum of the transverse missing momentum and the transverse momentum of the lepton. Depending on the signal model, the signals regions have varying sensitivity. Here we concentrate on gluino-gluino production, where the pair-produced gluinos decay to a top-antitop pair and the lightest neutralino.

  12. Strategies for improving memory: a randomized trial of memory groups for older people, including those with mild cognitive impairment.

    Science.gov (United States)

    Kinsella, Glynda J; Ames, David; Storey, Elsdon; Ong, Ben; Pike, Kerryn E; Saling, Michael M; Clare, Linda; Mullaly, Elizabeth; Rand, Elizabeth

    2016-01-01

    Governments are promoting the importance of maintaining cognitive health into older age to minimize risk of cognitive decline and dementia. Older people with amnestic mild cognitive impairment (aMCI) are particularly vulnerable to memory challenges in daily activities and are seeking ways to maintain independent living. To evaluate the effectiveness of memory groups for improving memory strategies and memory ability of older people, especially those with aMCI. 113 healthy older adults (HOA) and 106 adults with aMCI were randomized to a six-week memory group or a waitlist control condition. Outcome was evaluated through knowledge and use of memory strategies, memory ability (self-report and neuropsychological tests), and wellbeing. Assessments included a six-month follow-up. Using intention to treat analyses, there were intervention effects for HOA and aMCI groups in strategy knowledge (HOA: η2= 0.20; aMCI: η2= 0.06), strategy use (HOA: η2= 0.18; aMCI: η2= 0.08), and wellbeing (HOA: η2= 0.11; aMCI: η2= 0.05). There were also intervention effects in the HOA group, but not the aMCI group, in self-reported memory ability (η2= 0.06) and prospective memory tests (η2= 0.02). By six-month follow-up, gains were found on most HOA outcomes. In the aMCI group gains were found in strategy use, and by this stage, gains in prospective memory were also found. Memory groups can engage older people in techniques for maintaining cognitive health and improve memory performance, but more modest benefits are seen for older adults with aMCI.

  13. An audit strategy for time-to-event outcomes measured with error: application to five randomized controlled trials in oncology.

    Science.gov (United States)

    Dodd, Lori E; Korn, Edward L; Freidlin, Boris; Gu, Wenjuan; Abrams, Jeffrey S; Bushnell, William D; Canetta, Renzo; Doroshow, James H; Gray, Robert J; Sridhara, Rajeshwari

    2013-10-01

    Measurement error in time-to-event end points complicates interpretation of treatment effects in clinical trials. Non-differential measurement error is unlikely to produce large bias [1]. When error depends on treatment arm, bias is of greater concern. Blinded-independent central review (BICR) of all images from a trial is commonly undertaken to mitigate differential measurement-error bias that may be present in hazard ratios (HRs) based on local evaluations. Similar BICR and local evaluation HRs may provide reassurance about the treatment effect, but BICR adds considerable time and expense to trials. We describe a BICR audit strategy [2] and apply it to five randomized controlled trials to evaluate its use and to provide practical guidelines. The strategy requires BICR on a subset of study subjects, rather than a complete-case BICR, and makes use of an auxiliary-variable estimator. When the effect size is relatively large, the method provides a substantial reduction in the size of the BICRs. In a trial with 722 participants and a HR of 0.48, an average audit of 28% of the data was needed and always confirmed the treatment effect as assessed by local evaluations. More moderate effect sizes and/or smaller trial sizes required larger proportions of audited images, ranging from 57% to 100% for HRs ranging from 0.55 to 0.77 and sample sizes between 209 and 737. The method is developed for a simple random sample of study subjects. In studies with low event rates, more efficient estimation may result from sampling individuals with events at a higher rate. The proposed strategy can greatly decrease the costs and time associated with BICR, by reducing the number of images undergoing review. The savings will depend on the underlying treatment effect and trial size, with larger treatment effects and larger trials requiring smaller proportions of audited data.

  14. Recruitment of young adults for weight gain prevention: randomized comparison of direct mail strategies.

    Science.gov (United States)

    Crane, Melissa M; LaRose, Jessica Gokee; Espeland, Mark A; Wing, Rena R; Tate, Deborah F

    2016-06-08

    Recruiting young adults (ages 18-35 years) into weight gain prevention intervention studies is challenging and men are particularly difficult to reach. This paper describes two studies designed to improve recruitment for a randomized trial of weight gain prevention interventions. Study 1 used a quasi-experimental design to test the effect of two types of direct mailings on their overall reach. Study 2 used a randomized design to test the effect of using targeted messages to increase recruitment of men into the trial. For Study 1, 60,000 male and female young-adult households were randomly assigned to receive either a recruitment brochure or postcard. Visits to recruitment websites during each mailing period were used to assess response to each mailing. Study 2 focused on postcard recruitment only. These households received either a targeted or generic recruitment postcard, where targeted postcards included the word "Men" in the headline text. Response rates to each type of card were categorized based on participant report of mailing received. The reach of the postcards and brochures were similar (421 and 386 website visits, respectively; P = 0.22). Individuals who received the brochure were more likely to initiate the online screener than those who received a postcard (P = 0.01). In Study 2, of those who completed the telephone screening, 60.9 % of men (n = 23) had received the targeted postcard as compared to the generic postcard (39.1 %, P = 0.30). The reverse was true for women (n = 62, 38.7 vs. 61.3 %, P = 0.08). These studies suggest there was little difference in the reach of postcards versus brochures. However, recipients of brochures were more likely to continue to the next stage of study participation. As expected, men's response to the weight gain prevention messages was lower than women's response; but using targeted messages appears to have modestly increased the proportion of male respondents. These studies add to the limited

  15. Comparing of goal setting strategy with group education method to increase physical activity level: A randomized trial.

    Science.gov (United States)

    Jiryaee, Nasrin; Siadat, Zahra Dana; Zamani, Ahmadreza; Taleban, Roya

    2015-10-01

    Designing an intervention to increase physical activity is important to be based on the health care settings resources and be acceptable by the subject group. This study was designed to assess and compare the effect of the goal setting strategy with a group education method on increasing the physical activity of mothers of children aged 1 to 5. Mothers who had at least one child of 1-5 years were randomized into two groups. The effect of 1) goal-setting strategy and 2) group education method on increasing physical activity was assessed and compared 1 month and 3 months after the intervention. Also, the weight, height, body mass index (BMI), waist and hip circumference, and well-being were compared between the two groups before and after the intervention. Physical activity level increased significantly after the intervention in the goal-setting group and it was significantly different between the two groups after intervention (P goal-setting group after the intervention. In the group education method, only the well-being score improved significantly (P goal-setting strategy to boost physical activity, improving the state of well-being and decreasing BMI, waist, and hip circumference.

  16. Comparing of goal setting strategy with group education method to increase physical activity level: A randomized trial

    Directory of Open Access Journals (Sweden)

    Nasrin Jiryaee

    2015-01-01

    Full Text Available Background: Designing an intervention to increase physical activity is important to be based on the health care settings resources and be acceptable by the subject group. This study was designed to assess and compare the effect of the goal setting strategy with a group education method on increasing the physical activity of mothers of children aged 1 to 5. Materials and Methods: Mothers who had at least one child of 1-5 years were randomized into two groups. The effect of 1 goal-setting strategy and 2 group education method on increasing physical activity was assessed and compared 1 month and 3 months after the intervention. Also, the weight, height, body mass index (BMI, waist and hip circumference, and well-being were compared between the two groups before and after the intervention. Results: Physical activity level increased significantly after the intervention in the goal-setting group and it was significantly different between the two groups after intervention (P < 0.05. BMI, waist circumference, hip circumference, and well-being score were significantly different in the goal-setting group after the intervention. In the group education method, only the well-being score improved significantly (P < 0.05. Conclusion: Our study presented the effects of using the goal-setting strategy to boost physical activity, improving the state of well-being and decreasing BMI, waist, and hip circumference.

  17. Worksite Tobacco Prevention: A Randomized, Controlled Trial of Adoption, Dissemination Strategies, and Aggregated Health-Related Outcomes across Companies

    Directory of Open Access Journals (Sweden)

    Verena Friedrich

    2015-01-01

    Full Text Available Evidence based public health requires knowledge about successful dissemination of public health measures. This study analyses (a the changes in worksite tobacco prevention (TP in the Canton of Zurich, Switzerland, between 2007 and 2009; (b1 the results of a multistep versus a “brochure only” dissemination strategy; (b2 the results of a monothematic versus a comprehensive dissemination strategy that aim to get companies to adopt TP measures; and (c whether worksite TP is associated with health-related outcomes. A longitudinal design with randomized control groups was applied. Data on worksite TP and health-related outcomes were gathered by a written questionnaire (baseline n=1627; follow-up n=1452 and analysed using descriptive statistics, nonparametric procedures, and ordinal regression models. TP measures at worksites improved slightly between 2007 and 2009. The multistep dissemination was superior to the “brochure only” condition. No significant differences between the monothematic and the comprehensive dissemination strategies were observed. However, improvements in TP measures at worksites were associated with improvements in health-related outcomes. Although dissemination was approached at a mass scale, little change in the advocated adoption of TP measures was observed, suggesting the need for even more aggressive outreach or an acceptance that these channels do not seem to be sufficiently effective.

  18. Worksite Tobacco Prevention: A Randomized, Controlled Trial of Adoption, Dissemination Strategies, and Aggregated Health-Related Outcomes across Companies.

    Science.gov (United States)

    Friedrich, Verena; Brügger, Adrian; Bauer, Georg F

    2015-01-01

    Evidence based public health requires knowledge about successful dissemination of public health measures. This study analyses (a) the changes in worksite tobacco prevention (TP) in the Canton of Zurich, Switzerland, between 2007 and 2009; (b1) the results of a multistep versus a "brochure only" dissemination strategy; (b2) the results of a monothematic versus a comprehensive dissemination strategy that aim to get companies to adopt TP measures; and (c) whether worksite TP is associated with health-related outcomes. A longitudinal design with randomized control groups was applied. Data on worksite TP and health-related outcomes were gathered by a written questionnaire (baseline n = 1627; follow-up n = 1452) and analysed using descriptive statistics, nonparametric procedures, and ordinal regression models. TP measures at worksites improved slightly between 2007 and 2009. The multistep dissemination was superior to the "brochure only" condition. No significant differences between the monothematic and the comprehensive dissemination strategies were observed. However, improvements in TP measures at worksites were associated with improvements in health-related outcomes. Although dissemination was approached at a mass scale, little change in the advocated adoption of TP measures was observed, suggesting the need for even more aggressive outreach or an acceptance that these channels do not seem to be sufficiently effective.

  19. Did online publishers "get it right"? Using a naturalistic search strategy to review cognitive health promotion content on internet webpages.

    Science.gov (United States)

    Hunter, P V; Delbaere, M; O'Connell, M E; Cammer, A; Seaton, J X; Friedrich, T; Fick, F

    2017-06-15

    One of the most common uses of the Internet is to search for health-related information. Although scientific evidence pertaining to cognitive health promotion has expanded rapidly in recent years, it is unclear how much of this information has been made available to Internet users. Thus, the purpose of our study was to assess the reliability and quality of information about cognitive health promotion encountered by typical Internet users. To generate a list of relevant search terms employed by Internet users, we entered seed search terms in Google Trends and recorded any terms consistently used in the prior 2 years. To further approximate the behaviour of typical Internet users, we entered each term in Google and sampled the first two relevant results. This search, completed in October 2014, resulted in a sample of 86 webpages, 48 of which had content related to cognitive health promotion. An interdisciplinary team rated the information reliability and quality of these webpages using a standardized measure. We found that information reliability and quality were moderate, on average. Just one retrieved page mentioned best practice, national recommendations, or consensus guidelines by name. Commercial content (i.e., product promotion, advertising content, or non-commercial) was associated with differences in reliability and quality, with product promoter webpages having the lowest mean reliability and quality ratings. As efforts to communicate the association between lifestyle and cognitive health continue to expand, we offer these results as a baseline assessment of the reliability and quality of cognitive health promotion on the Internet.

  20. Hybrid and Cooperative Strategies Using Harmony Search and Artificial Immune Systems for Solving the Nurse Rostering Problem

    Directory of Open Access Journals (Sweden)

    Suk Ho Jin

    2017-06-01

    Full Text Available The nurse rostering problem is an important search problem that features many constraints. In a nurse rostering problem, these constraints are defined by processes such as maintaining work regulations, assigning nurse shifts, and considering nurse preferences. A number of approaches to address these constraints, such as penalty function methods, have been investigated in the literature. We propose two types of hybrid metaheuristic approaches for solving the nurse rostering problem, which are based on combining harmony search techniques and artificial immune systems to balance local and global searches and prevent slow convergence speeds and prematurity. The proposed algorithms are evaluated against a benchmarking dataset of nurse rostering problems; the results show that they identify better or best known solutions compared to those identified in other studies for most instances. The results also show that the combination of harmony search and artificial immune systems is better suited than using single metaheuristic or other hybridization methods for finding upper-bound solutions for nurse rostering problems and discrete optimization problems.

  1. Clinician search behaviors may be influenced by search engine design.

    Science.gov (United States)

    Lau, Annie Y S; Coiera, Enrico; Zrimec, Tatjana; Compton, Paul

    2010-06-30

    Searching the Web for documents using information retrieval systems plays an important part in clinicians' practice of evidence-based medicine. While much research focuses on the design of methods to retrieve documents, there has been little examination of the way different search engine capabilities influence clinician search behaviors. Previous studies have shown that use of task-based search engines allows for faster searches with no loss of decision accuracy compared with resource-based engines. We hypothesized that changes in search behaviors may explain these differences. In all, 75 clinicians (44 doctors and 31 clinical nurse consultants) were randomized to use either a resource-based or a task-based version of a clinical information retrieval system to answer questions about 8 clinical scenarios in a controlled setting in a university computer laboratory. Clinicians using the resource-based system could select 1 of 6 resources, such as PubMed; clinicians using the task-based system could select 1 of 6 clinical tasks, such as diagnosis. Clinicians in both systems could reformulate search queries. System logs unobtrusively capturing clinicians' interactions with the systems were coded and analyzed for clinicians' search actions and query reformulation strategies. The most frequent search action of clinicians using the resource-based system was to explore a new resource with the same query, that is, these clinicians exhibited a "breadth-first" search behaviour. Of 1398 search actions, clinicians using the resource-based system conducted 401 (28.7%, 95% confidence interval [CI] 26.37-31.11) in this way. In contrast, the majority of clinicians using the task-based system exhibited a "depth-first" search behavior in which they reformulated query keywords while keeping to the same task profiles. Of 585 search actions conducted by clinicians using the task-based system, 379 (64.8%, 95% CI 60.83-68.55) were conducted in this way. This study provides evidence that

  2. A randomized comparison of different ventilator strategies during thoracotomy for pulmonary resection.

    Science.gov (United States)

    Maslow, Andrew D; Stafford, Todd S; Davignon, Kristopher R; Ng, Thomas

    2013-07-01

    Protective lung ventilation is reported to benefit patients with acute respiratory distress syndrome. It is not known whether protective lung ventilation is also beneficial to patients undergoing single-lung ventilation for elective pulmonary resection. In an institutional review board-approved prospective randomized trial, 34 patients undergoing elective pulmonary resection requiring single-lung ventilation were enrolled. Informed consent was obtained. Patients were randomized to 1 of 2 groups: (1) high tidal volume (Hi-TV) of 10 mL/kg, rate of 7 breaths/min, and zero positive end-expiratory pressure or (2) low tidal volume (Lo-TV) of 5 mL/kg, rate of 14 breaths/min, and 5 cmH2O positive end-expiratory pressure. Ventilator settings were continued during both double- and single-lung ventilation. Pulmonary functions, hemodynamics, and postoperative outcomes were recorded. Patient demographics, operative characteristics, intraoperative hemodynamics, and postoperative pain and sedation scores were similar between the 2 groups. During most time periods, airway pressures (peak and plateau) were significantly higher in the Hi-TV group; however, plateau pressures remained less than 30 cmH2O at all times for all patients. The Hi-TV group had significantly lower arterial carbon dioxide tension, less arterial carbon dioxide tension-end-tidal carbon dioxide gradient, lower alveolar dead space ratio, and higher dynamic pulmonary compliance. There were no differences in postoperative morbidity and hospital days between the 2 groups, but atelectasis scores on postoperative days 1 and 2 were lower in the Hi-TV group. The use of Hi-TV during single-lung ventilation for pulmonary resection resulted in no increase in morbidity and was associated with less hypercarbia, less dead space ventilation, better dynamic compliance, and less postoperative atelectasis. Copyright © 2013 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  3. Eye Movement Training and Suggested Gaze Strategies in Tunnel Vision - A Randomized and Controlled Pilot Study.

    Science.gov (United States)

    Ivanov, Iliya V; Mackeben, Manfred; Vollmer, Annika; Martus, Peter; Nguyen, Nhung X; Trauzettel-Klosinski, Susanne

    2016-01-01

    Degenerative retinal diseases, especially retinitis pigmentosa (RP), lead to severe peripheral visual field loss (tunnel vision), which impairs mobility. The lack of peripheral information leads to fewer horizontal eye movements and, thus, diminished scanning in RP patients in a natural environment walking task. This randomized controlled study aimed to improve mobility and the dynamic visual field by applying a compensatory Exploratory Saccadic Training (EST). Oculomotor responses during walking and avoiding obstacles in a controlled environment were studied before and after saccade or reading training in 25 RP patients. Eye movements were recorded using a mobile infrared eye tracker (Tobii glasses) that measured a range of spatial and temporal variables. Patients were randomly assigned to two training conditions: Saccade (experimental) and reading (control) training. All subjects who first performed reading training underwent experimental training later (waiting list control group). To assess the effect of training on subjects, we measured performance in the training task and the following outcome variables related to daily life: Response Time (RT) during exploratory saccade training, Percent Preferred Walking Speed (PPWS), the number of collisions with obstacles, eye position variability, fixation duration, and the total number of fixations including the ones in the subjects' blind area of the visual field. In the saccade training group, RTs on average decreased, while the PPWS significantly increased. The improvement persisted, as tested 6 weeks after the end of the training. On average, the eye movement range of RP patients before and after training was similar to that of healthy observers. In both, the experimental and reading training groups, we found many fixations outside the subjects' seeing visual field before and after training. The average fixation duration was significantly shorter after the training, but only in the experimental training condition

  4. When Gravity Fails: Local Search Topology

    Science.gov (United States)

    Frank, Jeremy; Cheeseman, Peter; Stutz, John; Lau, Sonie (Technical Monitor)

    1997-01-01

    Local search algorithms for combinatorial search problems frequently encounter a sequence of states in which it is impossible to improve the value of the objective function; moves through these regions, called {\\em plateau moves), dominate the time spent in local search. We analyze and characterize {\\em plateaus) for three different classes of randomly generated Boolean Satisfiability problems. We identify several interesting features of plateaus that impact the performance of local search algorithms. We show that local minima tend to be small but occasionally may be very large. We also show that local minima can be escaped without unsatisfying a large number of clauses, but that systematically searching for an escape route may be computationally expensive if the local minimum is large. We show that plateaus with exits, called benches, tend to be much larger than minima, and that some benches have very few exit states which local search can use to escape. We show that the solutions (i.e. global minima) of randomly generated problem instances form clusters, which behave similarly to local minima. We revisit several enhancements of local search algorithms and explain their performance in light of our results. Finally we discuss strategies for creating the next generation of local search algorithms.

  5. Manipulating Google's Knowledge Graph Box to Counter Biased Information Processing During an Online Search on Vaccination: Application of a Technological Debiasing Strategy.

    Science.gov (United States)

    Ludolph, Ramona; Allam, Ahmed; Schulz, Peter J

    2016-06-02

    One of people's major motives for going online is the search for health-related information. Most consumers start their search with a general search engine but are unaware of the fact that its sorting and ranking criteria do not mirror information quality. This misconception can lead to distorted search outcomes, especially when the information processing is characterized by heuristic principles and resulting cognitive biases instead of a systematic elaboration. As vaccination opponents are vocal on the Web, the chance of encountering their non‒evidence-based views on immunization is high. Therefore, biased information processing in this context can cause subsequent impaired judgment and decision making. A technological debiasing strategy could counter this by changing people's search environment. This study aims at testing a technological debiasing strategy to reduce the negative effects of biased information processing when using a general search engine on people's vaccination-related knowledge and attitudes. This strategy is to manipulate the content of Google's knowledge graph box, which is integrated in the search interface and provides basic information about the search topic. A full 3x2 factorial, posttest-only design was employed with availability of basic factual information (comprehensible vs hardly comprehensible vs not present) as the first factor and a warning message as the second factor of experimental manipulation. Outcome variables were the evaluation of the knowledge graph box, vaccination-related knowledge, as well as beliefs and attitudes toward vaccination, as represented by three latent variables emerged from an exploratory factor analysis. Two-way analysis of variance revealed a significant main effect of availability of basic information in the knowledge graph box on participants' vaccination knowledge scores (F2,273=4.86, P=.01), skepticism/fear of vaccination side effects (F2,273=3.5, P=.03), and perceived information quality (F2

  6. Manipulating Google’s Knowledge Graph Box to Counter Biased Information Processing During an Online Search on Vaccination: Application of a Technological Debiasing Strategy

    Science.gov (United States)

    Allam, Ahmed; Schulz, Peter J

    2016-01-01

    Background One of people’s major motives for going online is the search for health-related information. Most consumers start their search with a general search engine but are unaware of the fact that its sorting and ranking criteria do not mirror information quality. This misconception can lead to distorted search outcomes, especially when the information processing is characterized by heuristic principles and resulting cognitive biases instead of a systematic elaboration. As vaccination opponents are vocal on the Web, the chance of encountering their non‒evidence-based views on immunization is high. Therefore, biased information processing in this context can cause subsequent impaired judgment and decision making. A technological debiasing strategy could counter this by changing people’s search environment. Objective This study aims at testing a technological debiasing strategy to reduce the negative effects of biased information processing when using a general search engine on people’s vaccination-related knowledge and attitudes. This strategy is to manipulate the content of Google’s knowledge graph box, which is integrated in the search interface and provides basic information about the search topic. Methods A full 3x2 factorial, posttest-only design was employed with availability of basic factual information (comprehensible vs hardly comprehensible vs not present) as the first factor and a warning message as the second factor of experimental manipulation. Outcome variables were the evaluation of the knowledge graph box, vaccination-related knowledge, as well as beliefs and attitudes toward vaccination, as represented by three latent variables emerged from an exploratory factor analysis. Results Two-way analysis of variance revealed a significant main effect of availability of basic information in the knowledge graph box on participants’ vaccination knowledge scores (F2,273=4.86, P=.01), skepticism/fear of vaccination side effects (F2,273=3.5, P=.03

  7. Eye Movement Training and Suggested Gaze Strategies in Tunnel Vision - A Randomized and Controlled Pilot Study.

    Directory of Open Access Journals (Sweden)

    Iliya V Ivanov

    Full Text Available Degenerative retinal diseases, especially retinitis pigmentosa (RP, lead to severe peripheral visual field loss (tunnel vision, which impairs mobility. The lack of peripheral information leads to fewer horizontal eye movements and, thus, diminished scanning in RP patients in a natural environment walking task. This randomized controlled study aimed to improve mobility and the dynamic visual field by applying a compensatory Exploratory Saccadic Training (EST.Oculomotor responses during walking and avoiding obstacles in a controlled environment were studied before and after saccade or reading training in 25 RP patients. Eye movements were recorded using a mobile infrared eye tracker (Tobii glasses that measured a range of spatial and temporal variables. Patients were randomly assigned to two training conditions: Saccade (experimental and reading (control training. All subjects who first performed reading training underwent experimental training later (waiting list control group. To assess the effect of training on subjects, we measured performance in the training task and the following outcome variables related to daily life: Response Time (RT during exploratory saccade training, Percent Preferred Walking Speed (PPWS, the number of collisions with obstacles, eye position variability, fixation duration, and the total number of fixations including the ones in the subjects' blind area of the visual field.In the saccade training group, RTs on average decreased, while the PPWS significantly increased. The improvement persisted, as tested 6 weeks after the end of the training. On average, the eye movement range of RP patients before and after training was similar to that of healthy observers. In both, the experimental and reading training groups, we found many fixations outside the subjects' seeing visual field before and after training. The average fixation duration was significantly shorter after the training, but only in the experimental training

  8. Flecainide in Amyotrophic Lateral Sclerosis as a Neuroprotective Strategy (FANS): A Randomized Placebo-Controlled Trial.

    Science.gov (United States)

    Park, Susanna B; Vucic, Steve; Cheah, Benjamin C; Lin, Cindy S-Y; Kirby, Adrienne; Mann, Kristy P; Zoing, Margie C; Winhammar, Jennica; Kiernan, Matthew C

    2015-12-01

    Abnormalities in membrane excitability and Na(+) channel function are characteristic of amyotrophic lateral sclerosis (ALS). We aimed to examine the neuroprotective potential, safety and tolerability of the Na(+) channel blocker and membrane stabiliser flecainide in ALS. A double-blind, placebo-controlled, randomised clinical trial of flecainide (200 mg/day) for 32-weeks with a 12-week lead-in phase was conducted in participants with probable or definite ALS recruited from multiple Australian centres (ANZCT Registry number ACTRN12608000338369). Patients were reviewed by a cardiologist to rule out cardiac contraindications. Participants were randomly assigned (1:1) to flecainide or placebo using stratified permuted blocks by a central pharmacy. The primary outcome measure was the slope of decline of the ALS Functional Rating Scale-revised (ALS FRS-r) during the treatment period. Between March 11, 2008 and July 1, 2010, 67 patients were screened, 54 of whom were randomly assigned to receive flecainide (26 patients) or placebo (28 patients). Four patients in the flecainide group and three patients in the placebo group withdrew from the study. One patient in the flecainide group died during the study, attributed to disease progression. Flecainide was generally well tolerated, with no serious adverse events reported in either group. There was no significant difference in the rate of decline in the primary outcome measure ALS-FRS-r between placebo and flecainide treated patients (Flecainide 0.65 [95% CI 0.49 to 0.98]; Placebo 0.81 [0.49 to 2.12] P = 0.50). However, the rate of decline of the neurophysiological index was significantly reduced in the flecainide group (Flecainide 0.06 [0.01 to 0.11]; Placebo 0.14 [0.09 to 0.19], P = 0.02). Placebo-treated patients demonstrated greater CMAP amplitude reduction during the course of the study in the subset of patients with a reduced baseline CMAP amplitude (Flecainide: - 15 ± 12%; Placebo - 59 ± 12%; P = 0.03). Flecainide

  9. Comparison of minimalist footwear strategies for simulating barefoot running: a randomized crossover study.

    Directory of Open Access Journals (Sweden)

    Karsten Hollander

    Full Text Available Possible benefits of barefoot running have been widely discussed in recent years. Uncertainty exists about which footwear strategy adequately simulates barefoot running kinematics. The objective of this study was to investigate the effects of athletic footwear with different minimalist strategies on running kinematics. Thirty-five distance runners (22 males, 13 females, 27.9 ± 6.2 years, 179.2 ± 8.4 cm, 73.4 ± 12.1 kg, 24.9 ± 10.9 km x week(-1 performed a treadmill protocol at three running velocities (2.22, 2.78 and 3.33 m x s(-1 using four footwear conditions: barefoot, uncushioned minimalist shoes, cushioned minimalist shoes, and standard running shoes. 3D kinematic analysis was performed to determine ankle and knee angles at initial foot-ground contact, rate of rear-foot strikes, stride frequency and step length. Ankle angle at foot strike, step length and stride frequency were significantly influenced by footwear conditions (p<0.001 at all running velocities. Posthoc pairwise comparisons showed significant differences (p<0.001 between running barefoot and all shod situations as well as between the uncushioned minimalistic shoe and both cushioned shoe conditions. The rate of rear-foot strikes was lowest during barefoot running (58.6% at 3.33 m x s(-1, followed by running with uncushioned minimalist shoes (62.9%, cushioned minimalist (88.6% and standard shoes (94.3%. Aside from showing the influence of shod conditions on running kinematics, this study helps to elucidate differences between footwear marked as minimalist shoes and their ability to mimic barefoot running adequately. These findings have implications on the use of footwear applied in future research debating the topic of barefoot or minimalist shoe running.

  10. Comparison of minimalist footwear strategies for simulating barefoot running: a randomized crossover study.

    Science.gov (United States)

    Hollander, Karsten; Argubi-Wollesen, Andreas; Reer, Rüdiger; Zech, Astrid

    2015-01-01

    Possible benefits of barefoot running have been widely discussed in recent years. Uncertainty exists about which footwear strategy adequately simulates barefoot running kinematics. The objective of this study was to investigate the effects of athletic footwear with different minimalist strategies on running kinematics. Thirty-five distance runners (22 males, 13 females, 27.9 ± 6.2 years, 179.2 ± 8.4 cm, 73.4 ± 12.1 kg, 24.9 ± 10.9 km x week(-1)) performed a treadmill protocol at three running velocities (2.22, 2.78 and 3.33 m x s(-1)) using four footwear conditions: barefoot, uncushioned minimalist shoes, cushioned minimalist shoes, and standard running shoes. 3D kinematic analysis was performed to determine ankle and knee angles at initial foot-ground contact, rate of rear-foot strikes, stride frequency and step length. Ankle angle at foot strike, step length and stride frequency were significantly influenced by footwear conditions (prunning velocities. Posthoc pairwise comparisons showed significant differences (prunning barefoot and all shod situations as well as between the uncushioned minimalistic shoe and both cushioned shoe conditions. The rate of rear-foot strikes was lowest during barefoot running (58.6% at 3.33 m x s(-1)), followed by running with uncushioned minimalist shoes (62.9%), cushioned minimalist (88.6%) and standard shoes (94.3%). Aside from showing the influence of shod conditions on running kinematics, this study helps to elucidate differences between footwear marked as minimalist shoes and their ability to mimic barefoot running adequately. These findings have implications on the use of footwear applied in future research debating the topic of barefoot or minimalist shoe running.

  11. Universal principles governing multiple random searchers on complex networks: The logarithmic growth pattern and the harmonic law

    Science.gov (United States)

    Weng, Tongfeng; Zhang, Jie; Small, Michael; Harandizadeh, Bahareh; Hui, Pan

    2018-03-01

    We propose a unified framework to evaluate and quantify the search time of multiple random searchers traversing independently and concurrently on complex networks. We find that the intriguing behaviors of multiple random searchers are governed by two basic principles—the logarithmic growth pattern and the harmonic law. Specifically, the logarithmic growth pattern characterizes how the search time increases with the number of targets, while the harmonic law explores how the search time of multiple random searchers varies relative to that needed by individual searchers. Numerical and theoretical results demonstrate these two universal principles established across a broad range of random search processes, including generic random walks, maximal entropy random walks, intermittent strategies, and persistent random walks. Our results reveal two fundamental principles governing the search time of multiple random searchers, which are expected to facilitate investigation of diverse dynamical processes like synchronization and spreading.

  12. Effectiveness of a multi-level implementation strategy for ASD interventions: study protocol for two linked cluster randomized trials.

    Science.gov (United States)

    Brookman-Frazee, Lauren; Stahmer, Aubyn C

    2018-05-09

    The Centers for Disease Control (2018) estimates that 1 in 59 children has autism spectrum disorder, and the annual cost of ASD in the U.S. is estimated to be $236 billion. Evidence-based interventions have been developed and demonstrate effectiveness in improving child outcomes. However, research on generalizable methods to scale up these practices in the multiple service systems caring for these children has been limited and is critical to meet this growing public health need. This project includes two, coordinated studies testing the effectiveness of the Translating Evidence-based Interventions (EBI) for ASD: Multi-Level Implementation Strategy (TEAMS) model. TEAMS focuses on improving implementation leadership, organizational climate, and provider attitudes and motivation in order to improve two key implementation outcomes-provider training completion and intervention fidelity and subsequent child outcomes. The TEAMS Leadership Institute applies implementation leadership strategies and TEAMS Individualized Provider Strategies for training applies motivational interviewing strategies to facilitate provider and organizational behavior change. A cluster randomized implementation/effectiveness Hybrid, type 3, trial with a dismantling design will be used to understand the effectiveness of TEAMS and the mechanisms of change across settings and participants. Study #1 will test the TEAMS model with AIM HI (An Individualized Mental Health Intervention for ASD) in publicly funded mental health services. Study #2 will test TEAMS with CPRT (Classroom Pivotal Response Teaching) in education settings. Thirty-seven mental health programs and 37 school districts will be randomized, stratified by county and study, to one of four groups (Standard Provider Training Only, Standard Provider Training + Leader Training, Enhanced Provider Training, Enhanced Provider Training + Leader Training) to test the effectiveness of combining standard, EBI-specific training with the two TEAMS

  13. Use of online recruitment strategies in a randomized trial of cancer survivors.

    Science.gov (United States)

    Juraschek, Stephen P; Plante, Timothy B; Charleston, Jeanne; Miller, Edgar R; Yeh, Hsin-Chieh; Appel, Lawrence J; Jerome, Gerald J; Gayles, Debra; Durkin, Nowella; White, Karen; Dalcin, Arlene; Hermosilla, Manuel

    2018-04-01

    Despite widespread Internet adoption, online advertising remains an underutilized tool to recruit participants into clinical trials. Whether online advertising is a cost-effective method to enroll participants compared to other traditional forms of recruitment is not known. Recruitment for the Survivorship Promotion In Reducing IGF-1 Trial, a community-based study of cancer survivors, was conducted from June 2015 through December 2016 via in-person community fairs, advertisements in periodicals, and direct postal mailings. In addition, "Right Column" banner ads were purchased from Facebook to direct participants to the Survivorship Promotion In Reducing IGF-1 Trial website. Response rates, costs of traditional and online advertisements, and demographic data were determined and compared across different online and traditional recruitment strategies. Micro-trials optimizing features of online advertisements were also explored. Of the 406 respondents to our overall outreach efforts, 6% (24 of 406) were referred from online advertising. Facebook advertisements were shown over 3 million times (impressions) to 124,476 people, which resulted in 4401 clicks on our advertisement. Of these, 24 people ultimately contacted study staff, 6 underwent prescreening, and 4 enrolled in the study. The cost of online advertising per enrollee was $794 when targeting a general population versus $1426 when accounting for strategies that specifically targeted African Americans or men. By contrast, community fairs, direct mail, or periodicals cost $917, $799, or $436 per enrollee, respectively. Utilization of micro-trials to assess online ads identified subtleties (e.g. use of an advertisement title) that substantially impacted viewer interest in our trial. Online advertisements effectively directed a relevant population to our website, which resulted in new enrollees in the Survivorship Promotion In Reducing IGF-1 Trial at a cost comparable to traditional methods. Costs were

  14. Effectiveness of a clinical practice guideline implementation strategy for patients with anxiety disorders in primary care: cluster randomized trial.

    Science.gov (United States)

    Tello-Bernabé, Eugenia; Sanz-Cuesta, Teresa; del Cura-González, Isabel; de Santiago-Hernando, María L; Jurado-Sueiro, Montserrat; Fernández-Girón, Mercedes; García-de Blas, Francisca; Pensado-Freire, Higinio; Góngora-Maldonado, Francisco; de la Puente-Chamorro, María J; Rodríguez-Pasamontes, Carmen; Martín-Iglesias, Susana

    2011-12-01

    Anxiety is a common mental health problem seen in primary care. However, its management in clinical practice varies greatly. Clinical practice guidelines (CPGs) have the potential to reduce variations and improve the care received by patients by promoting interventions of proven benefit. However, uptake and adherence to their recommendations can be low. This study involves a community based on cluster randomized trial in primary healthcare centres in the Madrid Region (Spain). The project aims to determine whether the use of implementation strategy (including training session, information, opinion leader, reminders, audit, and feed-back) of CPG for patients with anxiety disorders in primary care is more effective than usual diffusion. The number of patients required is 296 (148 in each arm), all older than 18 years and diagnosed with generalized anxiety disorder, panic disorder, and panic attacks by the Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV). They are chosen by consecutive sampling. The main outcome variable is the change in two or more points into Goldberg anxiety scale at six and twelve months. Secondary outcome variables include quality of life (EuroQol 5D), and degree of compliance with the CPG recommendations on treatment, information, and referrals to mental health services. Main effectiveness will be analyzed by comparing the patients percentage improvement on the Goldberg scale between the intervention group and the control group. Logistic regression with random effects will be used to adjust for prognostic factors. Confounding factors or factors that might alter the effect recorded will be taken into account in this analysis. There is a need to identify effective implementation strategies for CPG for the management of anxiety disorders present in primary care. Ensuring the appropriate uptake of guideline recommendations can reduce clinical variation and improve the care patients receive. ISRCTN: ISRCTN83365316.

  15. Effectiveness of a clinical practice guideline implementation strategy for patients with anxiety disorders in primary care: cluster randomized trial

    Directory of Open Access Journals (Sweden)

    Tello-Bernabé Eugenia

    2011-12-01

    Full Text Available Abstract Background Anxiety is a common mental health problem seen in primary care. However, its management in clinical practice varies greatly. Clinical practice guidelines (CPGs have the potential to reduce variations and improve the care received by patients by promoting interventions of proven benefit. However, uptake and adherence to their recommendations can be low. Method/design This study involves a community based on cluster randomized trial in primary healthcare centres in the Madrid Region (Spain. The project aims to determine whether the use of implementation strategy (including training session, information, opinion leader, reminders, audit, and feed-back of CPG for patients with anxiety disorders in primary care is more effective than usual diffusion. The number of patients required is 296 (148 in each arm, all older than 18 years and diagnosed with generalized anxiety disorder, panic disorder, and panic attacks by the Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV. They are chosen by consecutive sampling. The main outcome variable is the change in two or more points into Goldberg anxiety scale at six and twelve months. Secondary outcome variables include quality of life (EuroQol 5D, and degree of compliance with the CPG recommendations on treatment, information, and referrals to mental health services. Main effectiveness will be analyzed by comparing the patients percentage improvement on the Goldberg scale between the intervention group and the control group. Logistic regression with random effects will be used to adjust for prognostic factors. Confounding factors or factors that might alter the effect recorded will be taken into account in this analysis. Discussion There is a need to identify effective implementation strategies for CPG for the management of anxiety disorders present in primary care. Ensuring the appropriate uptake of guideline recommendations can reduce clinical variation and improve the care

  16. Searching for the most cost-effective strategy for controlling epidemics spreading on regular and small-world networks.

    Science.gov (United States)

    Kleczkowski, Adam; Oleś, Katarzyna; Gudowska-Nowak, Ewa; Gilligan, Christopher A

    2012-01-07

    We present a combined epidemiological and economic model for control of diseases spreading on local and small-world networks. The disease is characterized by a pre-symptomatic infectious stage that makes detection and control of cases more difficult. The effectiveness of local (ring-vaccination or culling) and global control strategies is analysed by comparing the net present values of the combined cost of preventive treatment and illness. The optimal strategy is then selected by minimizing the total cost of the epidemic. We show that three main strategies emerge, with treating a large number of individuals (global strategy, GS), treating a small number of individuals in a well-defined neighbourhood of a detected case (local strategy) and allowing the disease to spread unchecked (null strategy, NS). The choice of the optimal strategy is governed mainly by a relative cost of palliative and preventive treatments. If the disease spreads within the well-defined neighbourhood, the local strategy is optimal unless the cost of a single vaccine is much higher than the cost associated with hospitalization. In the latter case, it is most cost-effective to refrain from prevention. Destruction of local correlations, either by long-range (small-world) links or by inclusion of many initial foci, expands the range of costs for which the NS is most cost-effective. The GS emerges for the case when the cost of prevention is much lower than the cost of treatment and there is a substantial non-local component in the disease spread. We also show that local treatment is only desirable if the disease spreads on a small-world network with sufficiently few long-range links; otherwise it is optimal to treat globally. In the mean-field case, there are only two optimal solutions, to treat all if the cost of the vaccine is low and to treat nobody if it is high. The basic reproduction ratio, R(0), does not depend on the rate of responsive treatment in this case and the disease always invades

  17. Outcomes of combined cardiovascular risk factor management strategies in type 2 diabetes: the ACCORD randomized trial.

    Science.gov (United States)

    Margolis, Karen L; O'Connor, Patrick J; Morgan, Timothy M; Buse, John B; Cohen, Robert M; Cushman, William C; Cutler, Jeffrey A; Evans, Gregory W; Gerstein, Hertzel C; Grimm, Richard H; Lipkin, Edward W; Narayan, K M Venkat; Riddle, Matthew C; Sood, Ajay; Goff, David C

    2014-06-01

    To compare effects of combinations of standard and intensive treatment of glycemia and either blood pressure (BP) or lipids in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial. ACCORD enrolled 10,251 type 2 diabetes patients aged 40-79 years at high risk for cardiovascular disease (CVD) events. Participants were randomly assigned to hemoglobin A1c goals of risk of the primary outcome was lower in the groups intensively treated for glycemia (hazard ratio [HR] 0.67; 95% CI 0.50-0.91), BP (HR 0.74; 95% CI 0.55-1.00), or both (HR 0.71; 95% CI 0.52-0.96) compared with combined standard BP and glycemia treatment. For secondary outcomes, MI was significantly reduced by intensive glycemia treatment and stroke by intensive BP treatment; most other HRs were neutral or favored intensive treatment groups. In the lipid trial, the general pattern of results showed no evidence of benefit of intensive regimens (whether single or combined) compared with combined standard lipid and glycemia treatment. The mortality HR was 1.33 (95% CI 1.02-1.74) in the standard lipid/intensive glycemia group compared with the standard lipid/standard glycemia group. In the ACCORD BP trial, compared with combined standard treatment, intensive BP or intensive glycemia treatment alone improved major CVD outcomes, without additional benefit from combining the two. In the ACCORD lipid trial, neither intensive lipid nor glycemia treatment produced an overall benefit, but intensive glycemia treatment increased mortality. © 2014 by the American Diabetes Association.

  18. Randomized Trial of Hypnosis as a Pain and Symptom Management Strategy in Adults with Sickle Cell Disease

    Science.gov (United States)

    Wallen, Gwenyth R; Middleton, Kimberly R; Ames, Nancy; Brooks, Alyssa T; Handel, Daniel

    2014-01-01

    Sickle cell disease (SCD) is the most common genetic disease in African-Americans, characterized by recurrent painful vaso-occlusive crises. Medical therapies for controlling or preventing crises are limited because of efficacy and/or toxicity. This is a randomized, controlled, single-crossover protocol of hypnosis for managing pain in SCD patients. Participants receive hypnosis from a trained hypnosis therapist followed by six weeks of self-hypnosis using digital media. Those in the control arm receive SCD education followed by a six-week waiting period before crossing over to the hypnosis arm of the study. Outcome measures include assessments of pain (frequency, intensity and quality), anxiety, coping strategies, sleep, depression, and health care utilization. To date, there are no published randomized, controlled trials evaluating the efficacy of hypnosis on SCD pain modulation in adults. Self-hypnosis for pain management may be helpful in modulating chronic pain, improving sleep quality, and decreasing use of narcotics in patients with SCD. TRIAL REGISTRATION ClinicalTrials.gov: NCT00393250 PMID:25520557

  19. Randomized Trial of Hypnosis as a Pain and Symptom Management Strategy in Adults with Sickle Cell Disease

    Directory of Open Access Journals (Sweden)

    Gwenyth R. Wallen

    2014-01-01

    Full Text Available Sickle cell disease (SCD is the most common genetic disease in African-Americans, characterized by recurrent painful vaso-occlusive crises. Medical therapies for controlling or preventing crises are limited because of efficacy and/or toxicity. This is a randomized, controlled, single-crossover protocol of hypnosis for managing pain in SCD patients. Participants receive hypnosis from a trained hypnosis therapist followed by six weeks of self-hypnosis using digital media. Those in the control arm receive SCD education followed by a six-week waiting period before crossing over to the hypnosis arm of the study. Outcome measures include assessments of pain (frequency, intensity and quality, anxiety, coping strategies, sleep, depression, and health care utilization. To date, there are no published randomized, controlled trials evaluating the efficacy of hypnosis on SCD pain modulation in adults. Self-hypnosis for pain management may be helpful in modulating chronic pain, improving sleep quality, and decreasing use of narcotics in patients with SCD. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00393250

  20. Teaching basic life support: a prospective randomized study on low-cost training strategies in secondary schools.

    Science.gov (United States)

    Van Raemdonck, Veerle; Monsieurs, Koenraad G; Aerenhouts, Dirk; De Martelaer, Kristine

    2014-08-01

    Cardiopulmonary resuscitation (CPR) training at school is recommended. Limited school resources prevent implementation. The learning efficacy of low-cost training strategies is unknown. To evaluate the efficacy of different CPR learning strategies using low-cost didactic tools. Children (n=593, 15-16 years) were randomized to four training conditions: (1) manikin+teacher instruction (control group), (2) manikin+video instruction, (3) foam dice+plastic bag+peer training+teacher instruction, and (4) foam dice+plastic bag+peer training+video instruction. After a 50 min training, a 3 min CPR test on a manikin was performed using SkillReporting Software (Laerdal, Norway), and repeated after 6 months. The data of children without previous CPR training were analysed. Analysis of variance and the χ-test assessed differences between groups. Complete data sets were available for 165 pupils. Initially, group 3 scored lower on the mean ventilation volume (Pbasics of CPR can be taught with alternative equipment if manikins are not available.

  1. Ringed Seal Search for Global Optimization via a Sensitive Search Model.

    Directory of Open Access Journals (Sweden)

    Younes Saadi

    Full Text Available The efficiency of a metaheuristic algorithm for global optimization is based on its ability to search and find the global optimum. However, a good search often requires to be balanced between exploration and exploitation of the search space. In this paper, a new metaheuristic algorithm called Ringed Seal Search (RSS is introduced. It is inspired by the natural behavior of the seal pup. This algorithm mimics the seal pup movement behavior and its ability to search and choose the best lair to escape predators. The scenario starts once the seal mother gives birth to a new pup in a birthing lair that is constructed for this purpose. The seal pup strategy consists of searching and selecting the best lair by performing a random walk to find a new lair. Affected by the sensitive nature of seals against external noise emitted by predators, the random walk of the seal pup takes two different search states, normal state and urgent state. In the normal state, the pup performs an intensive search between closely adjacent lairs; this movement is modeled via a Brownian walk. In an urgent state, the pup leaves the proximity area and performs an extensive search to find a new lair from sparse targets; this movement is modeled via a Levy walk. The switch between these two states is realized by the random noise emitted by predators. The algorithm keeps switching between normal and urgent states until the global optimum is reached. Tests and validations were performed using fifteen benchmark test functions to compare the performance of RSS with other baseline algorithms. The results show that RSS is more efficient than Genetic Algorithm, Particles Swarm Optimization and Cuckoo Search in terms of convergence rate to the global optimum. The RSS shows an improvement in terms of balance between exploration (extensive and exploitation (intensive of the search space. The RSS can efficiently mimic seal pups behavior to find best lair and provide a new algorithm to be

  2. Search Improvement Process-Chaotic Optimization-Particle Swarm Optimization-Elite Retention Strategy and Improved Combined Cooling-Heating-Power Strategy Based Two-Time Scale Multi-Objective Optimization Model for Stand-Alone Microgrid Operation

    Directory of Open Access Journals (Sweden)

    Fei Wang

    2017-11-01

    Full Text Available The optimal dispatching model for a stand-alone microgrid (MG is of great importance to its operation reliability and economy. This paper aims at addressing the difficulties in improving the operational economy and maintaining the power balance under uncertain load demand and renewable generation, which could be even worse in such abnormal conditions as storms or abnormally low or high temperatures. A new two-time scale multi-objective optimization model, including day-ahead cursory scheduling and real-time scheduling for finer adjustments, is proposed to optimize the operational cost, load shedding compensation and environmental benefit of stand-alone MG through controllable load (CL and multi-distributed generations (DGs. The main novelty of the proposed model is that the synergetic response of CL and energy storage system (ESS in real-time scheduling offset the operation uncertainty quickly. And the improved dispatch strategy for combined cooling-heating-power (CCHP enhanced the system economy while the comfort is guaranteed. An improved algorithm, Search Improvement Process-Chaotic Optimization-Particle Swarm Optimization-Elite Retention Strategy (SIP-CO-PSO-ERS algorithm with strong searching capability and fast convergence speed, was presented to deal with the problem brought by the increased errors between actual renewable generation and load and prior predictions. Four typical scenarios are designed according to the combinations of day types (work day or weekend and weather categories (sunny or rainy to verify the performance of the presented dispatch strategy. The simulation results show that the proposed two-time scale model and SIP-CO-PSO-ERS algorithm exhibit better performance in adaptability, convergence speed and search ability than conventional methods for the stand-alone MG’s operation.

  3. Strategic search from long-term memory: an examination of semantic and autobiographical recall.

    Science.gov (United States)

    Unsworth, Nash; Brewer, Gene A; Spillers, Gregory J

    2014-01-01

    Searching long-term memory is theoretically driven by both directed (search strategies) and random components. In the current study we conducted four experiments evaluating strategic search in semantic and autobiographical memory. Participants were required to generate either exemplars from the category of animals or the names of their friends for several minutes. Self-reported strategies suggested that participants typically relied on visualization strategies for both tasks and were less likely to rely on ordered strategies (e.g., alphabetic search). When participants were instructed to use particular strategies, the visualization strategy resulted in the highest levels of performance and the most efficient search, whereas ordered strategies resulted in the lowest levels of performance and fairly inefficient search. These results are consistent with the notion that retrieval from long-term memory is driven, in part, by search strategies employed by the individual, and that one particularly efficient strategy is to visualize various situational contexts that one has experienced in the past in order to constrain the search and generate the desired information.

  4. Innovative products and services with environmental benefits: design of search strategies for external knowledge and absorptive capacity

    OpenAIRE

    Mothe, Caroline; NGuyen-Thi, Uyen; Triguero-Cano, Angela

    2018-01-01

    International audience; Although the antecedents of environmental innovation and open innovation strategies have been well studied separately, the relationship between a firm's openness and environmental technological innovation still remains an interesting topic to research, especially in terms of the various modes of openness on the one hand and the product–process distinction on the other. This study relies on data from the French Community Innovation Survey to differentiate the associatio...

  5. Engaging Foster Parents in Treatment: A Randomized Trial of Supplementing Trauma-focused Cognitive Behavioral Therapy with Evidence-based Engagement Strategies

    OpenAIRE

    Dorsey, Shannon; Pullmann, Michael D.; Berliner, Lucy; Koschmann, Elizabeth; McKay, Mary; Deblinger, Esther

    2014-01-01

    The goal of this study was to examine the impact of supplementing Trauma-focused Cognitive Behavioral Therapy (TF-CBT; Cohen, Mannarino, & Deblinger, 2006) with evidence-based engagement strategies on foster parent and foster youth engagement in treatment, given challenges engaging foster parents in treatment. A randomized controlled trial of TF-CBT standard delivery compared to TF-CBT plus evidence-based engagement strategies was conducted with 47 children and adolescents in foster care and ...

  6. A simple strategy for subcloning and amplifying random multimegabase subchromosomal acentric DNA fragments as double minute chromosomes

    International Nuclear Information System (INIS)

    Hahn, P.J.; Giddings, L.; Lane, M.J.

    1989-01-01

    Restriction mapping of relatively large genomes (e.g. human) utilizing randomly generated DNA segments requires high mapping redundancy to successfully organize 'contigs' to represent the entire genome. The number of independent DNA segment maps required is dependent on the average size of a mapping segment; the larger the segment, the fewer required. The authors have developed a strategy for subcloning intact multimegabase subchromosomal fragments as double minute chromosomes. Such fragments could serve as primary mapping elements or as adjunct (linking) fragments to rapidly connect already existent contigs generated using yeast artificial chromosomes or cosmids. They present several lines of evidence supporting the viability of this approach. (1) X-ray treated EMT-6 mouse cells (7.5 Gr.) which are selected over several months with increasing levels of methotrexate (MTX) contain highly amplified circular DNA molecules (double minutes) which include the dihydrofolate reductase (DHFR) gene in a size range between 1,000 and 3,500 kilobases as determined by pulsed-field gel electrophoresis and these acentric chromosomal fragments have been stably maintained in culture for at least a year. (2) Preliminary data based on experiments involving fusion of X-irradiated Chinese Hamster Ovary (CH0 DG44) cells containing randomly inserted cotransfected Neomycin resistance and DHFR genes to mouse EMT-6 cells shows that the linked genes can be readily cotransferred as acentric subchromosomal fragment(s) suitable for gene amplification. (3) The studies of CHO cells with cell fusion transferred X-ray induced chromosomal fragments containing the natural CHO DHFR gene suggest that transferred chromosome fragments undergo gene amplification much more readily than nonfragmented endogenous DHFR genes

  7. An Improved Ensemble of Random Vector Functional Link Networks Based on Particle Swarm Optimization with Double Optimization Strategy.

    Science.gov (United States)

    Ling, Qing-Hua; Song, Yu-Qing; Han, Fei; Yang, Dan; Huang, De-Shuang

    2016-01-01

    For ensemble learning, how to select and combine the candidate classifiers are two key issues which influence the performance of the ensemble system dramatically. Random vector functional link networks (RVFL) without direct input-to-output links is one of suitable base-classifiers for ensemble systems because of its fast learning speed, simple structure and good generalization performance. In this paper, to obtain a more compact ensemble system with improved convergence performance, an improved ensemble of RVFL based on attractive and repulsive particle swarm optimization (ARPSO) with double optimization strategy is proposed. In the proposed method, ARPSO is applied to select and combine the candidate RVFL. As for using ARPSO to select the optimal base RVFL, ARPSO considers both the convergence accuracy on the validation data and the diversity of the candidate ensemble system to build the RVFL ensembles. In the process of combining RVFL, the ensemble weights corresponding to the base RVFL are initialized by the minimum norm least-square method and then further optimized by ARPSO. Finally, a few redundant RVFL is pruned, and thus the more compact ensemble of RVFL is obtained. Moreover, in this paper, theoretical analysis and justification on how to prune the base classifiers on classification problem is presented, and a simple and practically feasible strategy for pruning redundant base classifiers on both classification and regression problems is proposed. Since the double optimization is performed on the basis of the single optimization, the ensemble of RVFL built by the proposed method outperforms that built by some single optimization methods. Experiment results on function approximation and classification problems verify that the proposed method could improve its convergence accuracy as well as reduce the complexity of the ensemble system.

  8. Cost-effectiveness of a mild compared with a standard strategy for IVF: a randomized comparison using cumulative term live birth as the primary endpoint.

    Science.gov (United States)

    Polinder, S; Heijnen, E M E W; Macklon, N S; Habbema, J D F; Fauser, B J C M; Eijkemans, M J C

    2008-02-01

    BACKGROUND Conventional ovarian stimulation and the transfer of two embryos in IVF exhibits an inherent high probability of multiple pregnancies, resulting in high costs. We evaluated the cost-effectiveness of a mild compared with a conventional strategy for IVF. METHODS Four hundred and four patients were randomly assigned to undergo either mild ovarian stimulation/GnRH antagonist co-treatment combined with single embryo transfer, or standard stimulation/GnRH agonist long protocol and the transfer of two embryos. The main outcome measures are total costs of treatment within a 12 months period after randomization, and the relationship between total costs and proportion of cumulative pregnancies resulting in term live birth within 1 year of randomization. RESULTS Despite a significantly increased average number of IVF cycles (2.3 versus 1.7; P costs over a 12-month period (8333 versus euro10 745; P = 0.006) were observed using the mild strategy. This was mainly due to higher costs of the obstetric and post-natal period for the standard strategy, related to multiple pregnancies. The costs per pregnancy leading to term live birth were euro19 156 in the mild strategy and euro24 038 in the standard. The incremental cost-effectiveness ratio of the standard strategy compared with the mild strategy was euro185 000 per extra pregnancy leading to term live birth. CONCLUSIONS Despite an increased mean number of IVF cycles within 1 year, from an economic perspective, the mild treatment strategy is more advantageous per term live birth. It is unlikely, over a wide range of society's willingness-to-pay, that the standard treatment strategy is cost-effective, compared with the mild strategy.

  9. Effectiveness of a multifaceted implementation strategy on physicians' referral behavior to an evidence-based psychosocial intervention in dementia: a cluster randomized controlled trial

    NARCIS (Netherlands)

    Dopp, C.M.E.; Graff, M.J.L.; Teerenstra, S.; Nijhuis-Van der Sanden, M.W.; Olde Rikkert, M.G.M.; Vernooij-Dassen, M.J.F.J.

    2013-01-01

    BACKGROUND: To evaluate the effectiveness of a multifaceted implementation strategy on physicians' referral rate to and knowledge on the community occupational therapy in dementia program (COTiD program). METHODS: A cluster randomized controlled trial with 28 experimental and 17 control clusters was

  10. Enhancing the Interpretive Reading and Analytical Writing of Mainstreamed English Learners in Secondary School: Results from a Randomized Field Trial Using a Cognitive Strategies Approach

    Science.gov (United States)

    Olson, Carol Booth; Kim, James S.; Scarcella, Robin; Kramer, Jason; Pearson, Matthew; van Dyk, David A.; Collins, Penny; Land, Robert E.

    2012-01-01

    In this study, 72 secondary English teachers from the Santa Ana Unified School District were randomly assigned to participate in the Pathway Project, a cognitive strategies approach to teaching interpretive reading and analytical writing, or to a control condition involving typical district training focusing on teaching content from the textbook.…

  11. Efficacy of Self-Regulated Strategy Development Instruction for Developing Writers with and without Disabilities in Rural Schools: A Randomized Controlled Trial

    Science.gov (United States)

    Mason, Linda H.; Cramer, Anne Mong; Garwood, Justin D.; Varghese, Cheryl; Hamm, Jill; Murray, Allen

    2017-01-01

    A workshop with virtual consultation practice-based professional development model for self-regulated strategy development persuasive writing instruction was evaluated in a randomized controlled trial. Nineteen general education teachers and 564 Grade 5 and 6 students in 16 low-wealth rural schools participated. Following training, teachers…

  12. The Success Rate in a Complicated Spatial Memory Test Is Determined by Age, Sex, Life History and Search Strategies in Cynomolgus Monkeys

    DEFF Research Database (Denmark)

    Darusman, Huda S; Kalliokoski, Otto; Sajuthi, Dondin

    2014-01-01

    to failure and chronological memory recall. These strategies appeared to be shared by most subjects, however, the overall success rate appeared to also depend on individual characteristics including age, gender and whether the subject had been born in caged captivity or not. By elucidating some...... of six identical opaque cups. Although the task was challenging for all subjects, generating a high level of guesswork, evidence of common behaviors when approaching the spatial memory test were found. The search patterns employed by the monkeys suggest the use of landmark cues, adaption in response...... of the underlying cognitive mechanisms, these findings may serve to refine interpretation of future studies using similar delayed response tasks in non-human primates....

  13. Mastering Search Analytics Measuring SEO, SEM and Site Search

    CERN Document Server

    Chaters, Brent

    2011-01-01

    Many companies still approach Search Engine Optimization (SEO) and paid search as separate initiatives. This in-depth guide shows you how to use these programs as part of a comprehensive strategy-not just to improve your site's search rankings, but to attract the right people and increase your conversion rate. Learn how to measure, test, analyze, and interpret all of your search data with a wide array of analytic tools. Gain the knowledge you need to determine the strategy's return on investment. Ideal for search specialists, webmasters, and search marketing managers, Mastering Search Analyt

  14. Comparison of mailed invitation strategies to improve fecal occult blood test participation in men: protocol for a randomized controlled trial.

    Science.gov (United States)

    Duncan, Amy; Zajac, Ian; Flight, Ingrid; Stewart, Benjamin J R; Wilson, Carlene; Turnbull, Deborah

    2013-07-31

    Men have a significantly increased risk of being diagnosed with, and dying from, colorectal cancer (CRC) than women. Men also participate in fecal occult blood test (FOBT) screening at a lower rate than women. This study will determine whether strategies that target men's attitudes toward screening, and matched to stage of readiness to screen, increase men's FOBT participation compared to a standard approach. Eligible trial participants will be a national sample of 9,200 men aged 50 to 74 years, living in urban Australia and randomly selected from the Australian electoral roll. Trial participants will be mailed an advance notification letter, followed 2 weeks later by an invitation letter and a free fecal immunochemical test (FIT) kit. The intervention is a factorial design, randomized controlled trial (RCT) with four trial arms, including a control. The content of the advance notification and invitation letters will differ by trial arm as follows: 1) standard advance notification and standard invitation (control arm); 2) targeted advance notification and standard invitation; 3) standard advance notification and targeted invitation; and 4) targeted advance notification and targeted invitation. The standard letters will replicate as closely as possible the letters included in the Australian National Bowel Cancer Screening Program (NBCSP). Modified advance notification and invitation letters will incorporate additional messages to target men in the precontemplation (advance notification) and contemplation stages (invitation). The primary outcome is return of the completed FIT within 12 weeks of invitation. Analysts will be blinded to trial assignment and participants will be blinded to the use of varying invitational materials. Subsamples from each trial arm will complete baseline and endpoint surveys to measure the psychological impact of the intervention, and qualitative interviews will be conducted to evaluate attitudes toward the intervention. The outcomes of

  15. Search of associative memory.

    NARCIS (Netherlands)

    Raaijmakers, J.G.W.; Shiffrin, R.M.

    1981-01-01

    Describes search of associative memory (SAM), a general theory of retrieval from long-term memory that combines features of associative network models and random search models. It posits cue-dependent probabilistic sampling and recovery from an associative network, but the network is specified as a

  16. A randomized trial of two e-learning strategies for teaching substance abuse management skills to physicians.

    Science.gov (United States)

    Harris, John M; Sun, Huaping

    2013-09-01

    To compare the educational effectiveness of two virtual patient (VP)-based e-learning strategies, versus no training, in improving physicians' substance abuse management knowledge, attitudes, self-reported behaviors, and decision making. The 2011-2012 study was a posttest-only, three-arm, randomized controlled trial in 90 resident and 30 faculty physicians from five adult medicine primary care training programs. The intervention was one of two 2-hour VP-based e-learning programs, designed by national experts to teach structured screening, brief interventions, referral, and treatment skills. One used traditional problem solving with feedback (unworked example), and the other incorporated an expert demonstration first, followed by problem solving with feedback (worked example). The main outcome measure was performance on the Physicians' Competence in Substance Abuse Test (P-CSAT, maximum score = 315), a self-administered, previously validated measure of physicians' competence in managing substance abuse. The survey was completed at the outset of the study and two months later. Overall P-CSAT scores were virtually identical (202-211, P > .05) between both intervention groups and the no-training control group at both times. Average faculty P-CSAT scores (221.9, 224.6) were significantly higher (P study did not provide evidence that a brief, worked example, VP-based e-learning program or a traditional, unworked, VP-based e-learning program was superior to no training in improving physicians' substance abuse management skills. The study did provide additional evidence that the P-CSAT distinguishes between physicians who should possess different levels of substance abuse management skills.

  17. Strategies to Maximize Data Collection Response Rates in a Randomized Control Trial Focused on Children with Medical Complexity.

    Science.gov (United States)

    Finkelstein, Stanley M; Celebrezze, Margaret; Cady, Rhonda; Lunos, Scott; Looman, Wendy S

    2016-04-01

    Obtaining complete and timely subject data is key to the success of clinical trials, particularly for studies requiring data collected from subjects at home or other remote sites. A multifaceted strategy for data collection in a randomized controlled trial (RCT) focused on care coordination for children with medical complexity is described. The influences of data collection mode, incentives, and study group membership on subject response patterns are analyzed. Data collection included monthly healthcare service utilization (HCSU) calendars and annual surveys focused on care coordination outcomes. One hundred sixty-three families were enrolled in the 30-month TeleFamilies RCT. Subjects were 2-15 years of age at enrollment. HCSU data were collected by parent/guardian self-report using mail, e-mail, telephone, or texting. Surveys were collected by mail. Incentives were provided for completed surveys after 8 months to improve collection returns. Outcome measures were the number of HCSU calendars and surveys returned, the return interval, data collection mode, and incentive impact. Return rates of 90% for HCSU calendars and 82% for annual surveys were achieved. Mean return intervals were 72 and 65 days for HCSU and surveys, respectively. Survey response increased from 55% to 95% after introduction of a gift card and added research staff. High return rates for HCSU calendars and health-related surveys are attainable but required a flexible and personnel-intensive approach to collection methods. Family preference for data collection approach should be obtained at enrollment, should be modified as needed, and requires flexible options, training, intensive staff/family interaction, and patience.

  18. Recruitment strategies should not be randomly selected: empirically improving recruitment success and diversity in developmental psychology research

    Science.gov (United States)

    Sugden, Nicole A.; Moulson, Margaret C.

    2015-01-01

    Psychological and developmental research have been critiqued for the lack of diversity of research samples. Because differences in culture, race, and ethnicity can influence participant behavior, limited diversity limits the generalizability of the findings. These differences may also impact how participants behave in response to recruitment attempts, which suggests that recruitment itself may be leveraged to increase sample diversity. The goal of the current study was to determine what factors, within a recruitment interaction, could be leveraged to increase success and diversity when recruiting families with children for developmental research. Study 1 found three factors influenced success: (1) recruitment was more successful when other potential participants were also interested (i.e., recruiters were busy), (2) recruiters of particular races were more successful than recruiters of other races, and (3) differences in success were related to what the recruiter said to engage the potential participant (i.e., the script). The latter two factors interacted, suggesting some recruiters were using less optimal scripts. To improve success rates, study 2 randomly assigned scripts to recruiters and encouraged them to recruit more vigorously during busy periods. Study 2 found that two factors influenced success: (1) some scripts were more successful than others and (2) we were more successful at recruiting non-White potential participants than White participants. These two interacted, with some scripts being more successful with White and other scripts being more successful with non-White families. This intervention significantly increased recruitment success rate by 8.1% and the overall number of families recruited by 15.3%. These findings reveal that empirically evaluating and tailoring recruitment efforts based on the most successful strategies is effective in boosting diversity through increased participation of children from non-White families. PMID:25972829

  19. Search Strategy of Focused Crawler Based on Adaptive Immune Evolutionary Algorithm%基于自适应免疫进化算法的聚焦爬虫搜索策略

    Institute of Scientific and Technical Information of China (English)

    刘丽杰; 许楠; 李盼池

    2012-01-01

    聚焦爬虫是主题搜索引擎的核心部件。针对目前聚焦爬虫搜索策略的不足,提出基于主题相关度和页面重要性相结合的综合相关度来判别页面主题相关性,并采用自适应免疫进化算法这种搜索策略指导聚焦爬虫的爬行,实验结果证明,该算法下载的主题相关网页数所占比例明显高于最佳搜索和广度优先搜索算法的比例,具有更高的搜索效率。%Focused crawler was a core component of the topic search engine.To overcome the deficiency of focused crawler search strategy,a comprehensive value based on theme relevance and importance of page was proposed to determine the topic relevant of the page,and the adaptive immune evolutionary algorithm of this search strategy was used to guide the crawling strategy of focused crawler.The experiment results showed that the algorithm download the proportion to the number of webpage related to the themes was higher significantly than the best search and breadth first search algorithm and had higher searching efficiency.

  20. Prices and heterogeneous search costs

    NARCIS (Netherlands)

    Luis Moraga-Gonzalez, Jose; Sandor, Zsolt; Wildenbeest, Matthijs R.

    2017-01-01

    We study price formation in a model of consumer search for differentiated products in which consumers have heterogeneous search costs. We provide conditions under which a pure-strategy symmetric Nash equilibrium exists and is unique. Search costs affect two margins-the intensive search margin (or

  1. Search Help

    Science.gov (United States)

    Guidance and search help resource listing examples of common queries that can be used in the Google Search Appliance search request, including examples of special characters, or query term seperators that Google Search Appliance recognizes.

  2. Hands4U: the effects of a multifaceted implementation strategy on hand eczema prevalence in a healthcare setting. Results of a randomized controlled trial.

    Science.gov (United States)

    van der Meer, Esther W C; Boot, Cécile R L; van der Gulden, Joost W J; Knol, Dirk L; Jungbauer, Frank H W; Coenraads, Pieter Jan; Anema, Johannes R

    2015-05-01

    Healthcare workers have an increased risk of developing hand eczema. A multifaceted implementation strategy was developed to implement a guideline to prevent hand eczema among healthcare workers. To investigate the effects of the implementation strategy on self-reported hand eczema and preventive behaviour. A randomized controlled trial was performed. A total of 48 departments (n = 1649) were randomly allocated to the multifaceted implementation strategy or the control group. The strategy consisted of education, participatory working groups, and role models. Outcome measures were self-reported hand eczema and preventive behaviour. Data were collected at baseline, and 3, 6, 9 and 12 months of follow-up. Participants in the intervention group were significantly more likely to report hand eczema [odds ratio (OR) 1.45; 95% confidence interval (CI) 1.03-2.04], and they reported significantly less hand washing (B, - 0.38; 95%CI: - 0.48 to - 0.27), reported significantly more frequent use of a moisturizer (B, 0.30; 95%CI: 0.22-0.39) and were more likely to report wearing cotton undergloves (OR 6.33; 95%CI: 3.23-12.41) than participants in the control group 12 months after baseline. The strategy implemented can be used in practice, as it showed positive effects on preventive behaviour. More research is needed to investigate the unexpected effects on hand eczema. © 2014 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.

  3. Local beam angle optimization with linear programming and gradient search

    International Nuclear Information System (INIS)

    Craft, David

    2007-01-01

    The optimization of beam angles in IMRT planning is still an open problem, with literature focusing on heuristic strategies and exhaustive searches on discrete angle grids. We show how a beam angle set can be locally refined in a continuous manner using gradient-based optimization in the beam angle space. The gradient is derived using linear programming duality theory. Applying this local search to 100 random initial angle sets of a phantom pancreatic case demonstrates the method, and highlights the many-local-minima aspect of the BAO problem. Due to this function structure, we recommend a search strategy of a thorough global search followed by local refinement at promising beam angle sets. Extensions to nonlinear IMRT formulations are discussed. (note)

  4. Effectiveness of a multifaceted implementation strategy on physicians? referral behavior to an evidence-based psychosocial intervention in dementia: a cluster randomized controlled trial

    OpenAIRE

    D?pp, Carola ME; Graff, Maud JL; Teerenstra, Steven; Nijhuis-van der Sanden, Maria WG; Olde Rikkert, Marcel GM; Vernooij-Dassen, Myrra JFJ

    2013-01-01

    BACKGROUND: To evaluate the effectiveness of a multifaceted implementation strategy on physicians' referral rate to and knowledge on the community occupational therapy in dementia program (COTiD program). METHODS: A cluster randomized controlled trial with 28 experimental and 17 control clusters was conducted. Cluster included a minimum of one physician, one manager, and two occupational therapists. In the control group physicians and managers received no interventions and occupational therap...

  5. A description of a knowledge broker role implemented as part of a randomized controlled trial evaluating three knowledge translation strategies

    Directory of Open Access Journals (Sweden)

    O'Mara Linda

    2009-04-01

    Full Text Available Abstract Background A knowledge broker (KB is a popular knowledge translation and exchange (KTE strategy emerging in Canada to promote interaction between researchers and end users, as well as to develop capacity for evidence-informed decision making. A KB provides a link between research producers and end users by developing a mutual understanding of goals and cultures, collaborates with end users to identify issues and problems for which solutions are required, and facilitates the identification, access, assessment, interpretation, and translation of research evidence into local policy and practice. Knowledge-brokering can be carried out by individuals, groups and/or organizations, as well as entire countries. In each case, the KB is linked with a group of end users and focuses on promoting the integration of the best available evidence into policy and practice-related decisions. Methods A KB intervention comprised one of three KTE interventions evaluated in a randomized controlled trial. Results KB activities were classified into the following categories: initial and ongoing needs assessments; scanning the horizon; knowledge management; KTE; network development, maintenance, and facilitation; facilitation of individual capacity development in evidence informed decision making; and g facilitation of and support for organizational change. Conclusion As the KB role developed during this study, central themes that emerged as particularly important included relationship development, ongoing support, customized approaches, and opportunities for individual and organizational capacity development. The novelty of the KB role in public health provides a unique opportunity to assess the need for and reaction to the role and its associated activities. Future research should include studies to evaluate the effectiveness of KBs in different settings and among different health care professionals, and to explore the optimal preparation and training of KBs

  6. An open-label, randomized, controlled, multicenter study exploring two treatment strategies of rivaroxaban and a dose-adjusted oral vitamin K antagonist treatment strategy in subjects with atrial fibrillation who undergo percutaneous coronary intervention (PIONEER AF-PCI).

    Science.gov (United States)

    Gibson, C Michael; Mehran, Roxana; Bode, Christoph; Halperin, Johnathan; Verheugt, Freek; Wildgoose, Peter; van Eickels, Martin; Lip, Gregory Y H; Cohen, Marc; Husted, Steen; Peterson, Eric; Fox, Keith

    2015-04-01

    Guidelines recommendations regarding anticoagulant therapy after percutaneous coronary intervention (PCI) among patients with atrial fibrillation (AF) rely on retrospective, nonrandomized observational data. Currently, patients are treated with triple-therapy (dual antiplatelet therapy [DAPT] + oral anticoagulation therapy), but neither the duration of DAPT nor the level of anticoagulation has been studied in a randomized fashion. Recent studies also suggest dual pathway therapy with clopidogrel plus oral anticoagulation therapy may be superior, and other studies suggest that novel oral anticoagulants such as rivaroxaban may further improve patient outcomes. PIONEER AF-PCI (ClinicalTrials.gov NCT01830543) is an exploratory, open-label, randomized, multicenter clinical study assessing the safety of 2 rivaroxaban treatment strategies and 1 vitamin K antagonist (VKA) treatment strategy in subjects who have paroxysmal, persistent, or permanent nonvalvular AF and have undergone PCI with stent placement. Approximately 2,100 subjects will be randomized in a 1:1:1 ratio to receive either rivaroxaban 15 mg once daily plus clopidogrel 75 mg daily for 12 months (a WOEST trial-like strategy), or rivaroxaban 2.5 mg twice daily (with stratification to a prespecified duration of DAPT 1, 6, or 12 months, an ATLAS trial-like strategy), or dose-adjusted VKA once daily (with stratification to a prespecified duration of DAPT 1, 6, or 12 months, traditional triple therapy). All patients will be followed up for 12 months for the primary composite end point of Thrombolysis in Myocardial Infarction major bleeding, bleeding requiring medical attention, and minor bleeding (collectively, clinically significant bleeding). The PIONEER AF-PCI study is the first randomized comparison of VKA vs novel oral anticoagulant therapy in patients with NVAF receiving antiplatelet therapy after PCI to assess the relative risks of bleeding complications. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Electronic medication complete communication strategy for opioid prescriptions in the emergency department: Rationale and design for a three-arm provider randomized trial.

    Science.gov (United States)

    McCarthy, Danielle M; Courtney, D Mark; Lank, Patrick M; Cameron, Kenzie A; Russell, Andrea M; Curtis, Laura M; Kim, Kwang-Youn A; Walton, Surrey M; Montague, Enid; Lyden, Abbie L; Gravenor, Stephanie J; Wolf, Michael S

    2017-08-01

    Thousands of people die annually from prescription opioid overdoses; however there are few strategies to ensure patients receive medication risk information at the time of prescribing. To compare the effectiveness of the Emergency Department (ED) Electronic Medication Complete Communication (EMC 2 ) Opioid Strategy (with and without text messaging) to promote safe medication use and improved patient knowledge as compared to usual care. The ED EMC 2 Opioid Strategy consists of 5 automated components to promote safe medication use: 1) physician reminder to counsel, 2) inbox message sent on to the patient's primary care physician, 3) pharmacist message on the prescription to counsel, 4) MedSheet supporting prescription information, and 5) patient-centered Take-Wait-Stop wording of prescription instructions. This strategy will be assessed both with and without the addition of text messages via a three-arm randomized trial. The study will take place at an urban academic ED (annual volume>85,000) in Chicago, IL. Patients being discharged with a new prescription for hydrocodone-acetaminophen will be enrolled and randomized (based on their prescribing physician). The primary outcome of the study is medication safe use as measured by a demonstrated dosing task. Additionally actual safe use, patient knowledge and provider counseling will be measured. Implementation fidelity as well as costs will be reported. The ED EMC 2 Opioid Strategy embeds a risk communication strategy into the electronic health record and promotes medication counseling with minimal workflow disruption. This trial will evaluate the strategy's effectiveness and implementation fidelity as compared to usual care. This trial is registered on clinicaltrials.gov with identifier NCT02431793. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. A mixed methods protocol for developing and testing implementation strategies for evidence-based obesity prevention in childcare: a cluster randomized hybrid type III trial.

    Science.gov (United States)

    Swindle, Taren; Johnson, Susan L; Whiteside-Mansell, Leanne; Curran, Geoffrey M

    2017-07-18

    Despite the potential to reach at-risk children in childcare, there is a significant gap between current practices and evidence-based obesity prevention in this setting. There are few investigations of the impact of implementation strategies on the uptake of evidence-based practices (EBPs) for obesity prevention and nutrition promotion. This study protocol describes a three-phase approach to developing and testing implementation strategies to support uptake of EBPs for obesity prevention practices in childcare (i.e., key components of the WISE intervention). Informed by the i-PARIHS framework, we will use a stakeholder-driven evidence-based quality improvement (EBQI) process to apply information gathered in qualitative interviews on barriers and facilitators to practice to inform the design of implementation strategies. Then, a Hybrid Type III cluster randomized trial will compare a basic implementation strategy (i.e., intervention as usual) with an enhanced implementation strategy informed by stakeholders. All Head Start centers (N = 12) within one agency in an urban area in a southern state in the USA will be randomized to receive the basic or enhanced implementation with approximately 20 classrooms per group (40 educators, 400 children per group). The educators involved in the study, the data collectors, and the biostastician will be blinded to the study condition. The basic and enhanced implementation strategies will be compared on outcomes specified by the RE-AIM model (e.g., Reach to families, Effectiveness of impact on child diet and health indicators, Adoption commitment of agency, Implementation fidelity and acceptability, and Maintenance after 6 months). Principles of formative evaluation will be used throughout the hybrid trial. This study will test a stakeholder-driven approach to improve implementation, fidelity, and maintenance of EBPs for obesity prevention in childcare. Further, this study provides an example of a systematic process to develop

  9. Heavy charged scalars from c\\overline{s} fusion: a generic search strategy applied to a 3HDM with U(1) × U(1) family symmetry

    Science.gov (United States)

    Camargo-Molina, José Eliel; Mandal, Tanumoy; Pasechnik, Roman; Wessén, Jonas

    2018-03-01

    We describe a class of three Higgs doublet models (3HDMs) with a softly broken U(1) × U(1) family symmetry that enforces a Cabibbo-like quark mixing while forbidding tree-level flavour changing neutral currents. The hierarchy in the observed quark masses is partly explained by a softer hierarchy in the vacuum expectation values of the three Higgs doublets. As a consequence, the physical scalar spectrum contains a Standard Model (SM) like Higgs boson h 125 while exotic scalars couple the strongest to the second quark family, leading to rather unconventional discovery channels that could be probed at the Large Hadron Collider. In particular, we describe a search strategy for the lightest charged Higgs boson H ±, through the process c\\overline{s}\\to {H}+\\to {W}+{h}_{125} , using a multivariate analysis that leads to an excellent discriminatory power against the SM background. Although the analysis is applied to the proposed class of 3HDMs, we employ a model-independent formulation such that it can be applied to any other model with the same discovery channel.

  10. Convergence analysis for Latin-hypercube lattice-sample selection strategies for 3D correlated random hydraulic-conductivity fields

    OpenAIRE

    Simuta-Champo, R.; Herrera-Zamarrón, G. S.

    2010-01-01

    The Monte Carlo technique provides a natural method for evaluating uncertainties. The uncertainty is represented by a probability distribution or by related quantities such as statistical moments. When the groundwater flow and transport governing equations are solved and the hydraulic conductivity field is treated as a random spatial function, the hydraulic head, velocities and concentrations also become random spatial functions. When that is the case, for the stochastic simulation of groundw...

  11. Effective Strategies to Recruit Young Adults Into the TXT2BFiT mHealth Randomized Controlled Trial for Weight Gain Prevention

    Science.gov (United States)

    Balestracci, Kate; Wong, Annette TY; Hebden, Lana; McGeechan, Kevin; Denney-Wilson, Elizabeth; Harris, Mark F; Phongsavan, Philayrath; Bauman, Adrian; Allman-Farinelli, Margaret

    2015-01-01

    Background Younger adults are difficult to engage in preventive health, yet in Australia they are gaining more weight and increasing in waist circumference faster than middle-to-older adults. A further challenge to engaging 18- to 35-year-olds in interventions is the limited reporting of outcomes of recruitment strategies. Objective This paper describes the outcomes of strategies used to recruit young adults to a randomized controlled trial (RCT), healthy lifestyle mHealth program, TXT2BFiT, for prevention of weight gain. The progression from enquiry through eligibility check to randomization into the trial and the costs of recruitment strategies are reported. Factors associated with nonparticipation are explored. Methods Participants were recruited either via letters of invitation from general practitioners (GPs) or via electronic or print advertisements, including Facebook and Google—social media and advertising—university electronic newsletters, printed posters, mailbox drops, and newspapers. Participants recruited from GP invitation letters had an appointment booked with their GP for eligibility screening. Those recruited from other methods were sent an information pack to seek approval to participate from their own GP. The total number and source of enquiries were categorized according to eligibility and subsequent completion of steps to enrolment. Cost data and details of recruitment strategies were recorded. Results From 1181 enquiries in total from all strategies, 250 (21.17%) participants were randomized. A total of 5311 invitation letters were sent from 12 GP practices—16 participating GPs. A total of 131 patients enquired with 68 participants randomized (68/74 of those eligible, 92%). The other recruitment methods yielded the remaining 182 randomized participants. Enrolment from print media was 26% of enquiries, from electronic media was 20%, and from other methods was 3%. Across all strategies the average cost of recruitment was Australian Dollar

  12. Effective Strategies to Recruit Young Adults Into the TXT2BFiT mHealth Randomized Controlled Trial for Weight Gain Prevention.

    Science.gov (United States)

    Partridge, Stephanie R; Balestracci, Kate; Wong, Annette Ty; Hebden, Lana; McGeechan, Kevin; Denney-Wilson, Elizabeth; Harris, Mark F; Phongsavan, Philayrath; Bauman, Adrian; Allman-Farinelli, Margaret

    2015-06-05

    Younger adults are difficult to engage in preventive health, yet in Australia they are gaining more weight and increasing in waist circumference faster than middle-to-older adults. A further challenge to engaging 18- to 35-year-olds in interventions is the limited reporting of outcomes of recruitment strategies. This paper describes the outcomes of strategies used to recruit young adults to a randomized controlled trial (RCT), healthy lifestyle mHealth program, TXT2BFiT, for prevention of weight gain. The progression from enquiry through eligibility check to randomization into the trial and the costs of recruitment strategies are reported. Factors associated with nonparticipation are explored. Participants were recruited either via letters of invitation from general practitioners (GPs) or via electronic or print advertisements, including Facebook and Google-social media and advertising-university electronic newsletters, printed posters, mailbox drops, and newspapers. Participants recruited from GP invitation letters had an appointment booked with their GP for eligibility screening. Those recruited from other methods were sent an information pack to seek approval to participate from their own GP. The total number and source of enquiries were categorized according to eligibility and subsequent completion of steps to enrolment. Cost data and details of recruitment strategies were recorded. From 1181 enquiries in total from all strategies, 250 (21.17%) participants were randomized. A total of 5311 invitation letters were sent from 12 GP practices-16 participating GPs. A total of 131 patients enquired with 68 participants randomized (68/74 of those eligible, 92%). The other recruitment methods yielded the remaining 182 randomized participants. Enrolment from print media was 26% of enquiries, from electronic media was 20%, and from other methods was 3%. Across all strategies the average cost of recruitment was Australian Dollar (AUD) $139 per person. The least expensive

  13. National evaluation of strategies to reduce safety violations for working from heights in construction companies: results from a randomized controlled trial.

    Science.gov (United States)

    van der Molen, Henk F; den Herder, Aalt; Warning, Jan; Frings-Dresen, Monique H W

    2016-01-09

    The objective of this study is to evaluate the effectiveness of a face-to-face strategy and a direct mail strategy on safety violations while working from heights among construction companies compared to a control condition. Construction companies with workers at risk for fall injuries were eligible for this three-armed randomized controlled trial. In total, 27 cities were randomly assigned to intervention groups-where eligible companies were given either a face-to-face guidance strategy or a direct mailing strategy with access to internet facilities-or to a control group. The primary outcomes were the number and type of safety violations recorded by labor inspectors after three months. A process evaluation for both strategies was performed to determine reach, program implementation, satisfaction, knowledge and perceived safety behavior. A cost analysis was performed to establish the financial costs for each intervention strategy. Analyses were done by intention to treat. In total, 41% (n = 88) of the companies eligible for the face-to-face intervention participated and 73% (n = 69) for direct mail. Intervention materials were delivered to 69 % (face-to-face group) and 100 % (direct mail group); completion of intervention activities within companies was low. Satisfaction, increase in knowledge, and safety behavior did not differ between the intervention groups. Costs for personal advice were 28% higher than for direct mail. Ultimately, nine intervention companies were captured in the 288 worksite measurements performed by the labor inspectorate. No statistical differences in mean number of safety violations (1.8-2.4) or penalties (72%-100%) were found between the intervention and control groups based on all worksite inspections. No conclusions about the effect of face-to-face and direct mail strategies on safety violations could be drawn due to the limited number of intervention companies captured in the primary outcome measurements. The costs for a face

  14. 10-Year Mortality Outcome of a Routine Invasive Strategy Versus a Selective Invasive Strategy in Non-ST-Segment Elevation Acute Coronary Syndrome: The British Heart Foundation RITA-3 Randomized Trial.

    Science.gov (United States)

    Henderson, Robert A; Jarvis, Christopher; Clayton, Tim; Pocock, Stuart J; Fox, Keith A A

    2015-08-04

    The RITA-3 (Third Randomised Intervention Treatment of Angina) trial compared outcomes of a routine early invasive strategy (coronary arteriography and myocardial revascularization, as clinically indicated) to those of a selective invasive strategy (coronary arteriography for recurrent ischemia only) in patients with non-ST-segment elevation acute coronary syndrome (NSTEACS). At a median of 5 years' follow-up, the routine invasive strategy was associated with a 24% reduction in the odds of all-cause mortality. This study reports 10-year follow-up outcomes of the randomized cohort to determine the impact of a routine invasive strategy on longer-term mortality. We randomized 1,810 patients with NSTEACS to receive routine invasive or selective invasive strategies. All randomized patients had annual follow-up visits up to 5 years, and mortality was documented thereafter using data from the Office of National Statistics. Over 10 years, there were no differences in mortality between the 2 groups (all-cause deaths in 225 [25.1%] vs. 232 patients [25.4%]: p = 0.94; and cardiovascular deaths in 135 [15.1%] vs. 147 patients [16.1%]: p = 0.65 in the routine invasive and selective invasive groups, respectively). Multivariate analysis identified several independent predictors of 10-year mortality: age, previous myocardial infarction, heart failure, smoking status, diabetes, heart rate, and ST-segment depression. A modified post-discharge Global Registry of Acute Coronary Events (GRACE) score was used to calculate an individual risk score for each patient and to form low-risk, medium-risk, and high-risk groups. Risk of death within 10 years varied markedly from 14.4 % in the low-risk group to 56.2% in the high-risk group. This mortality trend did not depend on the assigned treatment strategy. The advantage of reduced mortality of routine early invasive strategy seen at 5 years was attenuated during later follow-up, with no evidence of a difference in outcome at 10 years

  15. Comparison of on-demand vs planned relaparotomy strategy in patients with severe peritonitis: a randomized trial

    NARCIS (Netherlands)

    van Ruler, Oddeke; Mahler, Cecilia W.; Boer, Kimberly R.; Reuland, E. Ascelijn; Gooszen, Hein G.; Opmeer, Brent C.; de Graaf, Peter W.; Lamme, Bas; Gerhards, Michael F.; Steller, E. Philip; van Till, J. W. Olivier; de Borgie, Corianne J. A. M.; Gouma, Dirk J.; Reitsma, Johannes B.; Boermeester, Marja A.

    2007-01-01

    CONTEXT: In patients with severe secondary peritonitis, there are 2 surgical treatment strategies following an initial emergency laparotomy: planned relaparotomy and relaparotomy only when the patient's condition demands it ("on-demand"). The on-demand strategy may reduce mortality, morbidity,

  16. Search efficiency of biased migration towards stationary or moving targets in heterogeneously structured environments

    Science.gov (United States)

    Azimzade, Youness; Mashaghi, Alireza

    2017-12-01

    Efficient search acts as a strong selective force in biological systems ranging from cellular populations to predator-prey systems. The search processes commonly involve finding a stationary or mobile target within a heterogeneously structured environment where obstacles limit migration. An open generic question is whether random or directionally biased motions or a combination of both provide an optimal search efficiency and how that depends on the motility and density of targets and obstacles. To address this question, we develop a simple model that involves a random walker searching for its targets in a heterogeneous medium of bond percolation square lattice and used mean first passage time (〈T 〉 ) as an indication of average search time. Our analysis reveals a dual effect of directional bias on the minimum value of 〈T 〉 . For a homogeneous medium, directionality always decreases 〈T 〉 and a pure directional migration (a ballistic motion) serves as the optimized strategy, while for a heterogeneous environment, we find that the optimized strategy involves a combination of directed and random migrations. The relative contribution of these modes is determined by the density of obstacles and motility of targets. Existence of randomness and motility of targets add to the efficiency of search. Our study reveals generic and simple rules that govern search efficiency. Our findings might find application in a number of areas including immunology, cell biology, ecology, and robotics.

  17. Searching low and high

    DEFF Research Database (Denmark)

    Laursen, Keld; Salter, Ammon

    2003-01-01

    AbstractThis paper examines the factors that influence whether firms draw from universities in theirinnovative activities. The link between the universities and industrial innovation, and the role ofdifferent search strategies in influencing the propensity of firms to use universities is explored.......The results suggest that firms who adopt `open' search strategies and invest in R&D are morelikely than other firms to draw from universities, indicating that managerial choice matters inshaping the propensity of firms to draw from universities.Key words: University-industry links, innovation, external search...

  18. Statistical signatures of a targeted search by bacteria

    Science.gov (United States)

    Jashnsaz, Hossein; Anderson, Gregory G.; Pressé, Steve

    2017-12-01

    Chemoattractant gradients are rarely well-controlled in nature and recent attention has turned to bacterial chemotaxis toward typical bacterial food sources such as food patches or even bacterial prey. In environments with localized food sources reminiscent of a bacterium’s natural habitat, striking phenomena—such as the volcano effect or banding—have been predicted or expected to emerge from chemotactic models. However, in practice, from limited bacterial trajectory data it is difficult to distinguish targeted searches from an untargeted search strategy for food sources. Here we use a theoretical model to identify statistical signatures of a targeted search toward point food sources, such as prey. Our model is constructed on the basis that bacteria use temporal comparisons to bias their random walk, exhibit finite memory and are subject to random (Brownian) motion as well as signaling noise. The advantage with using a stochastic model-based approach is that a stochastic model may be parametrized from individual stochastic bacterial trajectories but may then be used to generate a very large number of simulated trajectories to explore average behaviors obtained from stochastic search strategies. For example, our model predicts that a bacterium’s diffusion coefficient increases as it approaches the point source and that, in the presence of multiple sources, bacteria may take substantially longer to locate their first source giving the impression of an untargeted search strategy.

  19. Best practice guidance for the use of strategies to improve retention in randomized trials developed from two consensus workshops.

    Science.gov (United States)

    Brueton, Valerie; Stenning, Sally P; Stevenson, Fiona; Tierney, Jayne; Rait, Greta

    2017-08-01

    To develop best practice guidance for the use of retention strategies in randomized clinical trials (RCTs). Consensus development workshops conducted at two UK Clinical Trials Units. Sixty-six statisticians, clinicians, RCT coordinators, research scientists, research assistants, and data managers associated with RCTs participated. The consensus development workshops were based on the consensus development conference method used to develop best practice for treatment of medical conditions. Workshops commenced with a presentation of the evidence for incentives, communication, questionnaire format, behavioral, case management, and methodological retention strategies identified by a Cochrane review and associated qualitative study. Three simultaneous group discussions followed focused on (1) how convinced the workshop participants were by the evidence for retention strategies, (2) barriers to the use of effective retention strategies, (3) types of RCT follow-up that retention strategies could be used for, and (4) strategies for future research. Summaries of each group discussion were fed back to the workshop. Coded content for both workshops was compared for agreement and disagreement. Agreed consensus on best practice guidance for retention was identified. Workshop participants agreed best practice guidance for the use of small financial incentives to improve response to postal questionnaires in RCTs. Use of second-class post was thought to be adequate for postal communication with RCT participants. The most relevant validated questionnaire was considered best practice for collecting RCT data. Barriers identified for the use of effective retention strategies were: the small improvements seen in questionnaire response for the addition of monetary incentives, and perceptions among trialists that some communication strategies are outdated. Furthermore, there was resistance to change existing retention practices thought to be effective. Face-to-face and electronic follow

  20. Engaging foster parents in treatment: a randomized trial of supplementing trauma-focused cognitive behavioral therapy with evidence-based engagement strategies.

    Science.gov (United States)

    Dorsey, Shannon; Pullmann, Michael D; Berliner, Lucy; Koschmann, Elizabeth; McKay, Mary; Deblinger, Esther

    2014-09-01

    The goal of this study was to examine the impact of supplementing Trauma-focused Cognitive Behavioral Therapy (TF-CBT; Cohen et al., 2006) with evidence-based engagement strategies on foster parent and foster youth engagement in treatment, given challenges engaging foster parents in treatment. A randomized controlled trial of TF-CBT standard delivery compared to TF-CBT plus evidence-based engagement strategies was conducted with 47 children and adolescents in foster care and one of their foster parents. Attendance, engagement, and clinical outcomes were assessed 1 month into treatment, end of treatment, and 3 months post-treatment. Youth and foster parents who received TF-CBT plus evidence-based engagement strategies were more likely to be retained in treatment through four sessions and were less likely to drop out of treatment prematurely. The engagement strategies did not appear to have an effect on the number of canceled or no-show sessions or on treatment satisfaction. Clinical outcomes did not differ by study condition, but exploratory analyses suggest that youth had significant improvements with treatment. Strategies that specifically target engagement may hold promise for increasing access to evidence-based treatments and for increasing likelihood of treatment completion. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Effect of Roy's Adaptation Model-Guided Education on Coping Strategies of the Veterans with Lower Extremities Amputation: A Double-Blind Randomized Controlled Clinical Trial.

    Science.gov (United States)

    Farsi, Zahra; Azarmi, Somayeh

    2016-04-01

    Any defect in the extremities of the body can affect different life aspects. The purpose of this study was to investigate the effect of Roy's adaptation model-guided education on coping strategies of the veterans with lower extremities amputation. In a double-blind randomized controlled clinical trial, 60 veterans with lower extremities amputation referring to Kowsar Orthotics and Prosthetics Center of Veterans Clinic in Tehran, Iran were recruited using convenience method and randomly assigned to intervention and control groups in 2013-2014. Lazarus and Folkman coping strategies questionnaire was used to collect the data. After completing the questionnaires in both groups, maladaptive behaviours were determined in the intervention group and an education program based on Roy's adaptation model was implemented. After 2 months, both groups completed the questionnaires again. Data were analyzed using SPSS software. Independent T-test showed that the score of the dimensions of coping strategies did not have a statistically significant difference between the intervention and control groups in the pre-intervention stage (P>0.05). This test showed a statistically significant difference between the two groups in the post-intervention stage in terms of the scores of different dimensions of coping strategies (P>0.05), except in dimensions of social support seeking and positive appraisal (P>0.05). The findings of this research indicated that the Roy's adaptation model-guided education improved the majority of coping strategies in veterans with lower extremities amputation. It is recommended that further interventions based on Roy's adaptation model should be performed to improve the coping of the veterans with lower extremities amputation. IRCT2014081118763N1.

  2. Effect of perioperative insulin infusion on surgical morbidity and mortality: systematic review and meta-analysis of randomized trials.7

    DEFF Research Database (Denmark)

    Gandhi, G.Y.; Murad, M.H.; Flynn, D.N.

    2008-01-01

    OBJECTIVE: To conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate the effect of perioperative insulin infusion on outcomes important to patients. PATIENTS AND METHODS: We used 6 search strategies including an electronic database search of MEDLINE, EMBA...

  3. Protocol: Adaptive Implementation of Effective Programs Trial (ADEPT): cluster randomized SMART trial comparing a standard versus enhanced implementation strategy to improve outcomes of a mood disorders program.

    Science.gov (United States)

    Kilbourne, Amy M; Almirall, Daniel; Eisenberg, Daniel; Waxmonsky, Jeanette; Goodrich, David E; Fortney, John C; Kirchner, JoAnn E; Solberg, Leif I; Main, Deborah; Bauer, Mark S; Kyle, Julia; Murphy, Susan A; Nord, Kristina M; Thomas, Marshall R

    2014-09-30

    Despite the availability of psychosocial evidence-based practices (EBPs), treatment and outcomes for persons with mental disorders remain suboptimal. Replicating Effective Programs (REP), an effective implementation strategy, still resulted in less than half of sites using an EBP. The primary aim of this cluster randomized trial is to determine, among sites not initially responding to REP, the effect of adaptive implementation strategies that begin with an External Facilitator (EF) or with an External Facilitator plus an Internal Facilitator (IF) on improved EBP use and patient outcomes in 12 months. This study employs a sequential multiple assignment randomized trial (SMART) design to build an adaptive implementation strategy. The EBP to be implemented is life goals (LG) for patients with mood disorders across 80 community-based outpatient clinics (N = 1,600 patients) from different U.S. regions. Sites not initially responding to REP (defined as implementation costs, and organizational change. This study design will determine whether an off-site EF alone versus the addition of an on-site IF improves EBP uptake and patient outcomes among sites that do not respond initially to REP. It will also examine the value of delaying the provision of EF/IF for sites that continue to not respond despite EF. ClinicalTrials.gov identifier: NCT02151331.

  4. A cluster randomized controlled trial of strategies to increase adolescents' physical activity and motivation in physical education: results of the Motivating Active Learning in Physical Education (MALP) trial.

    Science.gov (United States)

    Lonsdale, Chris; Rosenkranz, Richard R; Sanders, Taren; Peralta, Louisa R; Bennie, Andrew; Jackson, Ben; Taylor, Ian M; Lubans, David R

    2013-11-01

    Physical education (PE) programs aim to promote physical activity (PA) and reach most school-aged youth. However, PA levels within PE lessons are often low. In this cluster-randomized controlled trial, we examined the effects of three self-determination theory-based motivational strategies on PA and sedentary behavior, as well as their hypothesized antecedents during PE lessons. Data were collected in Sydney, Australia (October-December 2011). After baseline testing, teachers (n=16) and their classes (n=288 students; M=13.6 years, 50.4% male) were randomly assigned to one of four teaching strategy conditions: (1) explaining relevance; (2) providing choice; (3) complete free choice; or (4) usual practice. Teachers then delivered the assigned strategy. Primary outcomes were accelerometer-assessed PA and student motivation during lessons. Secondary outcomes included sedentary behavior, perceptions of teachers' support and psychological needs satisfaction. The 'free choice' intervention increased PA (pmotivation, but students' autonomy increased during both choice-based interventions (p<.05). Promoting choice can produce short-term increases in PA and decreases in sedentary behavior, as well as increased perceived autonomy during PE lessons. © 2013.

  5. A cluster-randomized controlled trial of strategies to increase adolescents’ physical activity and motivation during physical education lessons: the Motivating Active Learning in Physical Education (MALP trial

    Directory of Open Access Journals (Sweden)

    Rosenkranz Richard R

    2012-10-01

    Full Text Available Abstract Background The physical activity (PA levels of many children and adolescents in Australia are currently insufficient to promote health benefits. Physical education (PE programs aim to promote PA and reach nearly all school-aged children, but PA levels within PE lessons are often low. PE teachers may influence children’s motivation to be physically active in PE lessons, but little is known about teacher strategies that effectively motivate children to participate in PA, and few intervention studies have examined motivational strategies in PE. The purpose of this study was to compare the effect of three motivational strategies, each based on Self-Determination Theory (SDT, on PA levels, and their hypothesized antecedents, during year 8 PE lessons. Methods/design This study employed a cluster-randomized controlled trial design. Following a familiarization session, PA levels and hypothesized PA antecedents were measured during a baseline lesson and a post-intervention or control lesson. Teachers (n = 16 and their classes from five secondary schools in Sydney, Australia were randomly assigned into four blocks and instructed to provide one of four 20-min lesson teaching strategy conditions: (1 explaining the relevance of activities; (2 providing choice from PA options selected by the teacher; (3 providing equipment and free choice of activities; or (4 usual practice. The primary outcomes were lesson time spent in moderate-to-vigorous PA, and motivation towards the lesson. Secondary outcomes were perceptions of teacher behavior, psychological needs satisfaction, and lesson time spent in sedentary behavior. PA and sedentary behavior were measured during baseline and post-intervention lessons with waist-mounted Actigraph GT3X accelerometers. Teacher behavior, psychological needs satisfaction, and motivation were assessed via questionnaires at the end of each lesson. Linear mixed-model analyses will be run on all outcomes, with students nested

  6. A cluster-randomized controlled trial of strategies to increase adolescents' physical activity and motivation during physical education lessons: the Motivating Active Learning in Physical Education (MALP) trial.

    Science.gov (United States)

    Rosenkranz, Richard R; Lubans, David R; Peralta, Louisa R; Bennie, Andrew; Sanders, Taren; Lonsdale, Chris

    2012-10-01

    The physical activity (PA) levels of many children and adolescents in Australia are currently insufficient to promote health benefits. Physical education (PE) programs aim to promote PA and reach nearly all school-aged children, but PA levels within PE lessons are often low. PE teachers may influence children's motivation to be physically active in PE lessons, but little is known about teacher strategies that effectively motivate children to participate in PA, and few intervention studies have examined motivational strategies in PE. The purpose of this study was to compare the effect of three motivational strategies, each based on Self-Determination Theory (SDT), on PA levels, and their hypothesized antecedents, during year 8 PE lessons. This study employed a cluster-randomized controlled trial design. Following a familiarization session, PA levels and hypothesized PA antecedents were measured during a baseline lesson and a post-intervention or control lesson. Teachers (n = 16) and their classes from five secondary schools in Sydney, Australia were randomly assigned into four blocks and instructed to provide one of four 20-min lesson teaching strategy conditions: (1) explaining the relevance of activities; (2) providing choice from PA options selected by the teacher; (3) providing equipment and free choice of activities; or (4) usual practice. The primary outcomes were lesson time spent in moderate-to-vigorous PA, and motivation towards the lesson. Secondary outcomes were perceptions of teacher behavior, psychological needs satisfaction, and lesson time spent in sedentary behavior. PA and sedentary behavior were measured during baseline and post-intervention lessons with waist-mounted Actigraph GT3X accelerometers. Teacher behavior, psychological needs satisfaction, and motivation were assessed via questionnaires at the end of each lesson. Linear mixed-model analyses will be run on all outcomes, with students nested within teachers as a random effect. Study

  7. Placement and promotion strategies to increase sales of healthier products in supermarkets in low-income, ethnically diverse neighborhoods: a randomized controlled trial.

    Science.gov (United States)

    Foster, Gary D; Karpyn, Allison; Wojtanowski, Alexis C; Davis, Erica; Weiss, Stephanie; Brensinger, Colleen; Tierney, Ann; Guo, Wensheng; Brown, Jeffery; Spross, Carly; Leuchten, Donna; Burns, Patrick J; Glanz, Karen

    2014-06-01

    The greater presence of supermarkets in low-income, high-minority neighborhoods has the potential to positively affect diet quality among those at greatest risk of obesity. In-store marketing strategies that draw attention to healthier products may be effective, sustainable, and scalable for improving diet quality and health. Few controlled studies of in-store marketing strategies to promote sales of healthier items in low-income, high-minority neighborhoods have been conducted. The objective of this study was to evaluate the effects of in-store marketing strategies to promote the purchase of specific healthier items in 5 product categories: milk, ready-to-eat cereal, frozen meals, in-aisle beverages, and checkout cooler beverages. The design was a cluster-randomized controlled trial conducted from 2011 to 2012. Eight urban supermarkets in low-income, high-minority neighborhoods were the unit of randomization, intervention, and analysis. Stores were matched on the percentage of sales from government food-assistance programs and store size and randomly assigned to an intervention or control group. The 4 intervention stores received a 6-mo, in-store marketing intervention that promoted the sales of healthier products through placement, signage, and product availability strategies. The 4 control stores received no intervention and were assessment-only controls. The main outcome measure was weekly sales of the targeted products, which was assessed on the basis of the stores' sales data. Intervention stores showed significantly greater sales of skim and 1% milk, water (in aisle and at checkout), and 2 of 3 types of frozen meals compared with control store sales during the same time period. No differences were found between the stores in sales of cereal, whole or 2% milk, beverages, or diet beverages. These data indicate that straightforward placement strategies can significantly enhance the sales of healthier items in several food and beverage categories. Such

  8. A Proposed Multisite Double-Blind Randomized Clinical Trial of Neurofeedback for ADHD: Need, Rationale, and Strategy

    Science.gov (United States)

    Kerson, Cynthia

    2013-01-01

    Objective: Additional treatments with persisting benefit are needed for ADHD. Because ADHD often shows excessive theta electroencephalogram (EEG) power, low beta, and excessive theta-beta ratio (TBR), a promising treatment is neurofeedback (NF) downtraining TBR. Although several nonblind randomized clinical trials (RCTs) show a medium-large…

  9. Visual search for arbitrary objects in real scenes

    Science.gov (United States)

    Alvarez, George A.; Rosenholtz, Ruth; Kuzmova, Yoana I.; Sherman, Ashley M.

    2011-01-01

    How efficient is visual search in real scenes? In searches for targets among arrays of randomly placed distractors, efficiency is often indexed by the slope of the reaction time (RT) × Set Size function. However, it may be impossible to define set size for real scenes. As an approximation, we hand-labeled 100 indoor scenes and used the number of labeled regions as a surrogate for set size. In Experiment 1, observers searched for named objects (a chair, bowl, etc.). With set size defined as the number of labeled regions, search was very efficient (~5 ms/item). When we controlled for a possible guessing strategy in Experiment 2, slopes increased somewhat (~15 ms/item), but they were much shallower than search for a random object among other distinctive objects outside of a scene setting (Exp. 3: ~40 ms/item). In Experiments 4–6, observers searched repeatedly through the same scene for different objects. Increased familiarity with scenes had modest effects on RTs, while repetition of target items had large effects (>500 ms). We propose that visual search in scenes is efficient because scene-specific forms of attentional guidance can eliminate most regions from the “functional set size” of items that could possibly be the target. PMID:21671156

  10. Visual search for arbitrary objects in real scenes.

    Science.gov (United States)

    Wolfe, Jeremy M; Alvarez, George A; Rosenholtz, Ruth; Kuzmova, Yoana I; Sherman, Ashley M

    2011-08-01

    How efficient is visual search in real scenes? In searches for targets among arrays of randomly placed distractors, efficiency is often indexed by the slope of the reaction time (RT) × Set Size function. However, it may be impossible to define set size for real scenes. As an approximation, we hand-labeled 100 indoor scenes and used the number of labeled regions as a surrogate for set size. In Experiment 1, observers searched for named objects (a chair, bowl, etc.). With set size defined as the number of labeled regions, search was very efficient (~5 ms/item). When we controlled for a possible guessing strategy in Experiment 2, slopes increased somewhat (~15 ms/item), but they were much shallower than search for a random object among other distinctive objects outside of a scene setting (Exp. 3: ~40 ms/item). In Experiments 4-6, observers searched repeatedly through the same scene for different objects. Increased familiarity with scenes had modest effects on RTs, while repetition of target items had large effects (>500 ms). We propose that visual search in scenes is efficient because scene-specific forms of attentional guidance can eliminate most regions from the "functional set size" of items that could possibly be the target.

  11. Search Patterns

    CERN Document Server

    Morville, Peter

    2010-01-01

    What people are saying about Search Patterns "Search Patterns is a delight to read -- very thoughtful and thought provoking. It's the most comprehensive survey of designing effective search experiences I've seen." --Irene Au, Director of User Experience, Google "I love this book! Thanks to Peter and Jeffery, I now know that search (yes, boring old yucky who cares search) is one of the coolest ways around of looking at the world." --Dan Roam, author, The Back of the Napkin (Portfolio Hardcover) "Search Patterns is a playful guide to the practical concerns of search interface design. It cont

  12. A randomized matched-pairs study of feasibility, acceptability, and effectiveness of systems consultation: a novel implementation strategy for adopting clinical guidelines for Opioid prescribing in primary care.

    Science.gov (United States)

    Quanbeck, Andrew; Brown, Randall T; Zgierska, Aleksandra E; Jacobson, Nora; Robinson, James M; Johnson, Roberta A; Deyo, Brienna M; Madden, Lynn; Tuan, Wen-Jan; Alagoz, Esra

    2018-01-25

    This paper reports on the feasibility, acceptability, and effectiveness of an innovative implementation strategy named "systems consultation" aimed at improving adherence to clinical guidelines for opioid prescribing in primary care. While clinical guidelines for opioid prescribing have been developed, they have not been widely implemented, even as opioid abuse reaches epidemic levels. We tested a blended implementation strategy consisting of several discrete implementation strategies, including audit and feedback, academic detailing, and external facilitation. The study compares four intervention clinics to four control clinics in a randomized matched-pairs design. Each systems consultant aided clinics on implementing the guidelines during a 6-month intervention consisting of monthly site visits and teleconferences/videoconferences. The mixed-methods evaluation employs the RE-AIM (Reach, Effectiveness, Adoption, Implementation, Maintenance) framework. Quantitative outcomes are compared using time series analysis. Qualitative methods included focus groups, structured interviews, and ethnographic field techniques. Seven clinics were randomly approached to recruit four intervention clinics. Each clinic designated a project team consisting of six to eight staff members, each with at least one prescriber. Attendance at intervention meetings was 83%. More than 80% of staff respondents agreed or strongly agreed with the statements: "I am more familiar with guidelines for safe opioid prescribing" and "My clinic's workflow for opioid prescribing is easier." At 6 months, statistically significant improvements were noted in intervention clinics in the percentage of patients with mental health screens, treatment agreements, urine drug tests, and opioid-benzodiazepine co-prescribing. At 12 months, morphine-equivalent daily dose was significantly reduced in intervention clinics compared to controls. The cost to deliver the strategy was $7345 per clinic. Adaptations were

  13. Randomization of grab-sampling strategies for estimating the annual exposure of U miners to Rn daughters.

    Science.gov (United States)

    Borak, T B

    1986-04-01

    Periodic grab sampling in combination with time-of-occupancy surveys has been the accepted procedure for estimating the annual exposure of underground U miners to Rn daughters. Temporal variations in the concentration of potential alpha energy in the mine generate uncertainties in this process. A system to randomize the selection of locations for measurement is described which can reduce uncertainties and eliminate systematic biases in the data. In general, a sample frequency of 50 measurements per year is sufficient to satisfy the criteria that the annual exposure be determined in working level months to within +/- 50% of the true value with a 95% level of confidence. Suggestions for implementing this randomization scheme are presented.

  14. Drinker prototype alteration and cue reminders as strategies in a tailored web-based intervention reducing adults' alcohol consumption: randomized controlled trial.

    Science.gov (United States)

    van Lettow, Britt; de Vries, Hein; Burdorf, Alex; Boon, Brigitte; van Empelen, Pepijn

    2015-02-04

    Excessive alcohol use is a prevalent and worldwide problem. Excessive drinking causes a significant burden of disease and is associated with both morbidity and excess mortality. Prototype alteration and provision of a cue reminder could be useful strategies to enhance the effectiveness of online tailored interventions for excessive drinking. Through a Web-based randomized controlled trial, 2 strategies (ie, prototype alteration and cue reminders) within an existing online personalized feedback intervention (Drinktest) aimed to reduce adults' excessive drinking. It was expected that both strategies would add to Drinktest and would result in reductions in alcohol consumption by intrinsic motivation and the seizure of opportunities to act. Participants were recruited online and through printed materials. Excessive drinking adults (N=2634) were randomly assigned to 4 conditions: original Drinktest, Drinktest plus prototype alteration, Drinktest plus cue reminder, and Drinktest plus prototype alteration and cue reminder. Evaluation took place at 1-month posttest and 6-month follow-up. Differences in drinking behavior, intentions, and behavioral willingness (ie, primary outcomes) were assessed by means of longitudinal multilevel analyses using a last observation carried forward method. Measures were based on self-reports. All conditions showed reductions in drinking behavior and willingness to drink, and increased intentions to reduce drinking. Prototype alteration (B=-0.15, Pprototypes. Thus, prototype alteration and cue reminder usage may be feasible and simple intervention strategies to promote reductions in alcohol consumption among adults, with an effect up to 6 months. Nederlands Trial Register (NTR): 4169; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=4169 (Archived by WebCite at http://www.webcitation.org/6VD2jnxmB).

  15. Drinker Prototype Alteration and Cue Reminders as Strategies in a Tailored Web-Based Intervention Reducing Adults’ Alcohol Consumption: Randomized Controlled Trial

    Science.gov (United States)

    2015-01-01

    Background Excessive alcohol use is a prevalent and worldwide problem. Excessive drinking causes a significant burden of disease and is associated with both morbidity and excess mortality. Prototype alteration and provision of a cue reminder could be useful strategies to enhance the effectiveness of online tailored interventions for excessive drinking. Objective Through a Web-based randomized controlled trial, 2 strategies (ie, prototype alteration and cue reminders) within an existing online personalized feedback intervention (Drinktest) aimed to reduce adults’ excessive drinking. It was expected that both strategies would add to Drinktest and would result in reductions in alcohol consumption by intrinsic motivation and the seizure of opportunities to act. Methods Participants were recruited online and through printed materials. Excessive drinking adults (N=2634) were randomly assigned to 4 conditions: original Drinktest, Drinktest plus prototype alteration, Drinktest plus cue reminder, and Drinktest plus prototype alteration and cue reminder. Evaluation took place at 1-month posttest and 6-month follow-up. Differences in drinking behavior, intentions, and behavioral willingness (ie, primary outcomes) were assessed by means of longitudinal multilevel analyses using a last observation carried forward method. Measures were based on self-reports. Results All conditions showed reductions in drinking behavior and willingness to drink, and increased intentions to reduce drinking. Prototype alteration (B=–0.15, Pprototypes. Thus, prototype alteration and cue reminder usage may be feasible and simple intervention strategies to promote reductions in alcohol consumption among adults, with an effect up to 6 months. Trial Registration Nederlands Trial Register (NTR): 4169; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=4169 (Archived by WebCite at http://www.webcitation.org/6VD2jnxmB). PMID:25653199

  16. Combining rational and random strategies in β-glucosidase Zm-p60.1 protein library construction.

    Directory of Open Access Journals (Sweden)

    Dušan Turek

    Full Text Available Saturation mutagenesis is a cornerstone technique in protein engineering because of its utility (in conjunction with appropriate analytical techniques for assessing effects of varying residues at selected positions on proteins' structures and functions. Site-directed mutagenesis with degenerate primers is the simplest and most rapid saturation mutagenesis technique. Thus, it is highly appropriate for assessing whether or not variation at certain sites is permissible, but not necessarily the most time- and cost-effective technique for detailed assessment of variations' effects. Thus, in the presented study we applied the technique to randomize position W373 in β-glucosidase Zm-p60.1, which is highly conserved among β-glucosidases. Unexpectedly, β-glucosidase activity screening of the generated variants showed that most variants were active, although they generally had significantly lower activity than the wild type enzyme. Further characterization of the library led us to conclude that a carefully selected combination of randomized codon-based saturation mutagenesis and site-directed mutagenesis may be most efficient, particularly when constructing and investigating randomized libraries with high fractions of positive hits.

  17. Combining rational and random strategies in β-glucosidase Zm-p60.1 protein library construction.

    Science.gov (United States)

    Turek, Dušan; Klimeš, Pavel; Mazura, Pavel; Brzobohatý, Břetislav

    2014-01-01

    Saturation mutagenesis is a cornerstone technique in protein engineering because of its utility (in conjunction with appropriate analytical techniques) for assessing effects of varying residues at selected positions on proteins' structures and functions. Site-directed mutagenesis with degenerate primers is the simplest and most rapid saturation mutagenesis technique. Thus, it is highly appropriate for assessing whether or not variation at certain sites is permissible, but not necessarily the most time- and cost-effective technique for detailed assessment of variations' effects. Thus, in the presented study we applied the technique to randomize position W373 in β-glucosidase Zm-p60.1, which is highly conserved among β-glucosidases. Unexpectedly, β-glucosidase activity screening of the generated variants showed that most variants were active, although they generally had significantly lower activity than the wild type enzyme. Further characterization of the library led us to conclude that a carefully selected combination of randomized codon-based saturation mutagenesis and site-directed mutagenesis may be most efficient, particularly when constructing and investigating randomized libraries with high fractions of positive hits.

  18. Investigating bang for your training buck: a randomized controlled trial comparing three methods of training clinicians in two core strategies of dialectical behavior therapy.

    Science.gov (United States)

    Dimeff, Linda A; Harned, Melanie S; Woodcock, Eric A; Skutch, Julie M; Koerner, Kelly; Linehan, Marsha M

    2015-05-01

    The present study examined the efficacy of online training (OLT), instructor-led training (ILT), and a treatment manual (TM) in training mental health clinicians in two core strategies of Dialectical Behavior Therapy (DBT): chain analysis and validation. A randomized controlled trial compared OLT, ILT, and TM among clinicians naïve to DBT (N=172) who were assessed at baseline, post-training, and 30, 60, and 90 days following training. Primary outcomes included satisfaction, self-efficacy, motivation, knowledge, clinical proficiency, and clinical use. Overall, ILT outperformed OLT and TM in satisfaction, self-efficacy, and motivation, whereas OLT was the most effective method for increasing knowledge. The conditions did not differ in observer-rated clinical proficiency or self-reported clinical use, which both increased to moderate levels after training. In addition, ILT was particularly effective at improving motivation to use chain analysis, whereas OLT was particularly effective at increasing knowledge of validation strategies. These findings suggest that these types of brief, didactic trainings may be effective methods of increasing knowledge of new treatment strategies, but may not be sufficient to enable clinicians to achieve a high level of clinical use or proficiency. Additional research examining the possible advantages of matching training methods to types of treatment strategies may help to determine a tailored, more effective approach to training clinicians in empirically supported treatments. Copyright © 2015. Published by Elsevier Ltd.

  19. A Randomized Control Trial of Working Memory Training With and Without Strategy Instruction: Effects on Young Children's Working Memory and Comprehension.

    Science.gov (United States)

    Peng, Peng; Fuchs, Douglas

    2017-01-01

    Researchers are increasingly interested in working memory (WM) training. However, it is unclear whether it strengthens comprehension in young children who are at risk for learning difficulties. We conducted a modest study of whether the training of verbal WM would improve verbal WM and passage listening comprehension and whether training effects differed between two approaches: training with and without strategy instruction. A total of 58 first-grade children were randomly assigned to three groups: WM training with a rehearsal strategy, WM training without strategy instruction, and controls. Each member of the two training groups received a one-to-one, 35-min session of verbal WM training on each of 10 consecutive school days, totaling 5.8 hr. Both training groups improved on trained verbal WM tasks, with the rehearsal group making greater gains. Without correction for multiple group comparisons, the rehearsal group made reliable improvements over controls on an untrained verbal WM task and on passage listening comprehension and listening retell measures. The no-strategy-instruction group outperformed controls on passage listening comprehension. When corrected for multiple contrasts, these group differences disappeared but were associated with moderate to large effect sizes. Findings suggest-however tentatively-that brief but intensive verbal WM training may strengthen the verbal WM and comprehension performance of young children at risk. Necessary caveats and possible implications for theory and future research are discussed. © Hammill Institute on Disabilities 2015.

  20. A Randomized Control Trial of Working Memory Training With and Without Strategy Instruction: Effects on Young Children’s Working Memory and Comprehension

    Science.gov (United States)

    Peng, Peng

    2015-01-01

    Researchers are increasingly interested in working memory (WM) training. However, it is unclear whether it strengthens comprehension in young children who are at risk for learning difficulties. We conducted a modest study of whether the training of verbal WM would improve verbal WM and passage listening comprehension, and whether training effects differed between two approaches: training with and without strategy instruction. A total of 58 first-grade children were randomly assigned to 3 groups: WM training with a rehearsal strategy, WM training without strategy instruction, and controls. Every member of the 2 training groups received a one-to-one, 35-minute session of verbal WM training on each of 10 consecutive school days, totaling 5.8 hours. Both training groups improved on trained verbal WM tasks, with the rehearsal group making greater gains. Without correction for multiple group comparisons, the rehearsal group made reliable improvements over controls on an untrained verbal WM task and on passage listening comprehension and listening retell measures. The no-strategy- instruction group outperformed controls on passage listening comprehension. When corrected for multiple contrasts, these group differences disappeared, but were associated with moderate-to-large effect sizes. Findings suggest—however tentatively—that brief but intensive verbal WM training may strengthen the verbal WM and comprehension performance of young children at risk. Necessary caveats and possible implications for theory and future research are discussed. PMID:26156961

  1. Random sampling or geostatistical modelling? Choosing between design-based and model-based sampling strategies for soil (with discussion)

    NARCIS (Netherlands)

    Brus, D.J.; Gruijter, de J.J.

    1997-01-01

    Classical sampling theory has been repeatedly identified with classical statistics which assumes that data are identically and independently distributed. This explains the switch of many soil scientists from design-based sampling strategies, based on classical sampling theory, to the model-based

  2. Composite Differential Search Algorithm

    Directory of Open Access Journals (Sweden)

    Bo Liu

    2014-01-01

    Full Text Available Differential search algorithm (DS is a relatively new evolutionary algorithm inspired by the Brownian-like random-walk movement which is used by an organism to migrate. It has been verified to be more effective than ABC, JDE, JADE, SADE, EPSDE, GSA, PSO2011, and CMA-ES. In this paper, we propose four improved solution search algorithms, namely “DS/rand/1,” “DS/rand/2,” “DS/current to rand/1,” and “DS/current to rand/2” to search the new space and enhance the convergence rate for the global optimization problem. In order to verify the performance of different solution search methods, 23 benchmark functions are employed. Experimental results indicate that the proposed algorithm performs better than, or at least comparable to, the original algorithm when considering the quality of the solution obtained. However, these schemes cannot still achieve the best solution for all functions. In order to further enhance the convergence rate and the diversity of the algorithm, a composite differential search algorithm (CDS is proposed in this paper. This new algorithm combines three new proposed search schemes including “DS/rand/1,” “DS/rand/2,” and “DS/current to rand/1” with three control parameters using a random method to generate the offspring. Experiment results show that CDS has a faster convergence rate and better search ability based on the 23 benchmark functions.

  3. 'Doctor Google' ending the diagnostic odyssey in lysosomal storage disorders: parents using internet search engines as an efficient diagnostic strategy in rare diseases.

    Science.gov (United States)

    Bouwman, Machtelt G; Teunissen, Quirine G A; Wijburg, Frits A; Linthorst, Gabor E

    2010-08-01

    The expansion of the internet has resulted in widespread availability of medical information for both patients and physicians. People increasingly spend time on the internet searching for an explanation, diagnosis or treatment for their symptoms. Regarding rare diseases, the use of the internet may be an important tool in the diagnostic process. The authors present two cases in which concerned parents made a correct diagnosis of a lysosomal storage disorder in their child by searching the internet after a long doctor's delay. These cases illustrate the utility of publicly available internet search engines in diagnosing rare disorders and in addition illustrate the lengthy diagnostic odyssey which is common in these disorders.

  4. Hemodialysis without Systemic Anticoagulation: A Prospective Randomized Trial to Evaluate 3 Strategies in Patients at Risk of Bleeding

    Science.gov (United States)

    Guéry, Bruno; Alberti, Corinne; Servais, Aude; Harrami, Elarbi; Bererhi, Lynda; Zins, Brigitte; Touam, Malik; Joly, Dominique

    2014-01-01

    Objective In this clinical trial, we aimed to compare three means of performing chronic hemodialysis in patients with contra-indication to systemic heparinization. Methods This open-label monocentric randomized « n-of-one » trial, conducted in a single tertiary care center, recruited chronic hemodialysis patients with a contra-indication to systemic heparinization for at least 3 consecutive sessions. All patients underwent hemodialysis with an AN69ST dialyzer, and were administered three alternative dialysis procedures in a random sequence: intermittent saline flushes, constant saline infusion, or pre-dialysis heparin coating of the membrane. The primary outcome was the need to interrupt the dialysis session because of clotting events due to either (i) a complete coagulation of the circuit; (ii) a partial coagulation of the circuit; (iii) a>50% rise over baseline in the venous pressure. Results At the end of the inclusion period (May, 2007 to December, 2008), the number of patients to include (n = 75) was not reached: only 46 patients were included and underwent randomization. The study was terminated, and statistical analysis took into account 224 hemodialysis sessions performed in 44 patients with analyzable data. Heparin adsorption was associated with a significant reduction of the need to interrupt the dialysis session because of clotting events: odds ratio 0.3 (CI 95% 0.2 to 0.6; p3 h dialysis sessions and for having complete blood restitution. There were no significant effects of the dialysis procedure on weight loss, online ionic dialysance, and adverse events. Conclusion Heparin-coated AN69ST dialysis membrane is a safe and effective method to avoid or delay per-dialytic clotting events in patients with contra-indication to systemic anticoagulation. However, results are not generalizable safely to patients with active bleeding, since weak heparinemia, not assessed in this study, may occur. Trial Registration ClinicalTrials.gov NCT00473109. PMID

  5. Random Assignment of Schools to Groups in the Drug Resistance Strategies Rural Project: Some New Methodological Twists

    Science.gov (United States)

    Pettigrew, Jonathan; Miller-Day, Michelle; Krieger, Janice L.; Zhou, Jiangxiu; Hecht, Michael L.

    2014-01-01

    Random assignment to groups is the foundation for scientifically rigorous clinical trials. But assignment is challenging in group randomized trials when only a few units (schools) are assigned to each condition. In the DRSR project, we assigned 39 rural Pennsylvania and Ohio schools to three conditions (rural, classic, control). But even with 13 schools per condition, achieving pretest equivalence on important variables is not guaranteed. We collected data on six important school-level variables: rurality, number of grades in the school, enrollment per grade, percent white, percent receiving free/assisted lunch, and test scores. Key to our procedure was the inclusion of school-level drug use data, available for a subset of the schools. Also, key was that we handled the partial data with modern missing data techniques. We chose to create one composite stratifying variable based on the seven school-level variables available. Principal components analysis with the seven variables yielded two factors, which were averaged to form the composite inflate-suppress (CIS) score which was the basis of stratification. The CIS score was broken into three strata within each state; schools were assigned at random to the three program conditions from within each stratum, within each state. Results showed that program group membership was unrelated to the CIS score, the two factors making up the CIS score, and the seven items making up the factors. Program group membership was not significantly related to pretest measures of drug use (alcohol, cigarettes, marijuana, chewing tobacco; smallest p>.15), thus verifying that pretest equivalence was achieved. PMID:23722619

  6. Renal Function Following Three Distinct Weight Loss Dietary Strategies During 2 Years of a Randomized Controlled Trial

    OpenAIRE

    Tirosh, Amir; Golan, Rachel; Harman-Boehm, Ilana; Henkin, Yaakov; Schwarzfuchs, Dan; Rudich, Assaf; Kovsan, Julia; Fiedler, Georg M.; Blüher, Matthias; Stumvoll, Michael; Thiery, Joachim; Stampfer, Meir J.; Shai, Iris

    2013-01-01

    OBJECTIVE This study addressed the long-term effect of various diets, particularly low-carbohydrate high-protein, on renal function on participants with or without type 2 diabetes. RESEARCH DESIGN AND METHODS In the 2-year Dietary Intervention Randomized Controlled Trial (DIRECT), 318 participants (age, 51 years; 86% men; BMI, 31 kg/m2; mean estimated glomerular filtration rate [eGFR], 70.5 mL/min/1.73 m2; mean urine microalbumin-to-creatinine ratio, 12:12) with serum creatinine 0.05) across...

  7. Guidelines and Criteria for the Search Strategy, Evaluation, Selection, and Documentation of Key Data and Supporting Data Used for the Derivation of AEGL Values

    Science.gov (United States)

    This is Section 2.3 of the Standing Operating Procedures for Developing Acute Exposure Guideline Levels (AEGLs) for Hazardous Chemicals. It discusses methodologies used to search for and select data for development of AEGL values.

  8. Structural properties of small Lin (n = 5-8) atomic clusters via ab initio random structure searching: A look into the role of different implementations of long-range dispersion corrections

    Science.gov (United States)

    Putungan, Darwin Barayang; Lin, Shi-Hsin

    2018-01-01

    In this work, we looked into the lowest energy structures of small lithium clusters (Lin, n = 5, 6, 7, 8) utilizing conventional PBE exchange-correlation functional, PBE with D2 dispersion correction and PBE with Tkatchenko and Scheffler (TS) dispersion correction, and searched using ab initio random structure searching. Results show that in general, dispersion-corrected PBE obtained similar lowest minima structures as those obtained via conventional PBE regardless of the type of implementation, although both D2 and TS found several high-energy isomers that conventional PBE did not arrive at, with TS in general giving more structures per energy range that could be attributed to its environment-dependent implementation. Moreover, D2 and TS dispersion corrections found a lowest energy geometry for Li8 cluster that is in agreement with the structure obtained via the typical benchmarking method diffusion Monte Carlo in a recent work. It is thus suggested that for much larger lithium clusters, utilization of dispersion correction could be of help in searching for lowest energy minima that is in close agreement with that of diffusion Monte Carlo results, but computationally inexpensive.

  9. Autonomous change of behavior for environmental context: An intermittent search model with misunderstanding search pattern

    Science.gov (United States)

    Murakami, Hisashi; Gunji, Yukio-Pegio

    2017-07-01

    Although foraging patterns have long been predicted to optimally adapt to environmental conditions, empirical evidence has been found in recent years. This evidence suggests that the search strategy of animals is open to change so that animals can flexibly respond to their environment. In this study, we began with a simple computational model that possesses the principal features of an intermittent strategy, i.e., careful local searches separated by longer steps, as a mechanism for relocation, where an agent in the model follows a rule to switch between two phases, but it could misunderstand this rule, i.e., the agent follows an ambiguous switching rule. Thanks to this ambiguity, the agent's foraging strategy can continuously change. First, we demonstrate that our model can exhibit an optimal change of strategy from Brownian-type to Lévy-type depending on the prey density, and we investigate the distribution of time intervals for switching between the phases. Moreover, we show that the model can display higher search efficiency than a correlated random walk.

  10. Pharmacological strategies to reduce pruritus during postoperative epidural analgesia after lumbar fusion surgery - a prospective randomized trial in 150 patients

    Directory of Open Access Journals (Sweden)

    Robinson Yohan

    2011-05-01

    Full Text Available Abstract Background Epidural analgesia with bupivacain, epinephrine and fentanyl provides excellent pain control after lumbar fusion surgery, but pruritus and motor block are frequent side effects. Theoretically epidural ropivacain combined with oral oxycodone could decrease the incidence of these side effects. The two regimens were compared in a prospective randomized trial. Patients and methods 150 patients (87 women treated with posterior instrumented lumbar fusion were included. The mean age was 51 +/- 11 years. 76 were randomized to bupivacain, epinephrine and fentanyl (group B and 74 to ropivacain and oxycodone (group R. Pruritus, motor block and pain were measured 6 hours after surgery, thereafter 6 times per day for 5 days. Any pain breakthrough episode was registered whenever it occurred. Results The epidural treatment could be performed in 143 patients (72 in group B and 71 in group R. Disturbing pruritus occurred in 53 patients in group B compared to 12 in group R (p Conclusions Pruritus could be reduced with a combination of epidural ropivacain and oral oxycodone, at the price of a slightly higher pain level. Ropivacaine was not found to be superior to bupivacaine with regard to motor blocks.

  11. Introducing taxes, subsidies or both: the effects of various food pricing strategies in a web-based supermarket randomized trial.

    Science.gov (United States)

    Waterlander, Wilma E; Steenhuis, Ingrid H M; de Boer, Michiel R; Schuit, Albertine J; Seidell, Jacob C

    2012-05-01

    Fiscal policies may form a solution in improving dietary intake. This study aimed to examine the effectiveness of varying taxing and subsiding schemes to stimulate healthier food purchases. A randomized controlled trial with three levels of price reduction on healthy foods (no; 25%; 50%)×three levels of price increase on unhealthy foods (5%; 10%; 25%) factorial design was used. 150 participants were randomized into one of nine conditions and were asked to purchase groceries at a web-based supermarket. Data were collected in the Netherlands in January-February 2010 and analyzed using analysis of covariance. Subjects receiving 50% discount purchased significantly more healthy foods than subjects receiving no (mean difference=6.62 items, pprice increases on unhealthy foods were found. Price decreases are effective in stimulating healthy food purchases, but the proportion of healthy foods remains unaffected. Price increases up to 25% on unhealthier products do not significantly affect food purchases. Future studies are important to validate these results in real supermarkets and across different countries. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. The effect of feedback regarding coping strategies and illness behavior on hand surgery patient satisfaction and communication: a randomized controlled trial.

    Science.gov (United States)

    Mellema, Jos J; O'Connor, Casey M; Overbeek, Celeste L; Hageman, Michiel G; Ring, David

    2015-09-01

    Patients and surgeons can feel uncomfortable discussing coping strategies, psychological distress, and stressful circumstances. It has been suggested that patient-reported outcome measures (PROMs) facilitate the discussion of factors associated with increased symptoms and disability. This study assessed the effect of providing feedback to patients regarding their coping strategy and illness behavior on patient satisfaction and patient-physician communication in orthopedic surgery. In a prospective study, 136 orthopedic patients were randomly assigned to either receive feedback about the Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference computer-adaptive test (CAT) prior to the visit with the hand surgeon or not. The primary outcome was patient satisfaction with the consultation and secondary outcomes involved patient-physician communication. Bivariate and multivariable analyses were performed to determine the influence of the feedback on patient satisfaction and communication. There was no significant difference in patient satisfaction between patients who received feedback and patients who did not (P = 0.70). Feedback was associated with more frequent discussion of coping strategies (P = 0.045) in bivariate analysis but was not independently associated: in multivariable analysis, only PROMIS Pain Interference CAT and age were identified as independent predictors (odds ratio (OR) 1.1; 95 % confidence interval (CI) 1.0-1.1, P = 0.013, and OR 0.97, 95 % CI 0.94-0.99, P = 0.032, respectively). No factors were associated with discussion of stressors. Discussion of circumstances was independently associated with increased PROMIS Pain Interference CAT, marital status, and work status. We found that feedback regarding coping strategies and illness behavior using the PROMIS Pain Interference CAT did not affect patient satisfaction. Although feedback was associated with increased discussion of illness behavior in bivariate

  13. Effectiveness of a multi-strategy intervention in increasing the implementation of vegetable and fruit breaks by Australian primary schools: a non-randomized controlled trial.

    Science.gov (United States)

    Nathan, Nicole; Wolfenden, Luke; Bell, Andrew C; Wyse, Rebecca; Morgan, Philip J; Butler, Michelle; Sutherland, Rachel; Milat, Andrew J; Hector, Debra; Wiggers, John

    2012-08-13

    Limited evidence exists describing the effectiveness of strategies in facilitating the implementation of vegetable and fruit programs by schools on a population wide basis. The aim of this study was to examine the effectiveness of a multi-strategy intervention in increasing the population-wide implementation of vegetable and fruit breaks by primary schools and to determine if intervention effectiveness varied by school characteristics. A quasi-experimental study was conducted in primary schools in the state of New South Wales, Australia. All primary schools in one region of the state (n = 422) received a multi-strategy intervention. A random sample of schools (n = 406) in the remainder of the state served as comparison schools. The multi-strategy intervention to increase vegetable and fruit breaks involved the development and provision of: program consensus and leadership; staff training; program materials; incentives; follow-up support; and implementation feedback. Comparison schools had access to routine information-based Government support. Data to assess the prevalence of vegetable and fruit breaks were collected by telephone from Principals of the intervention and comparison schools at baseline (2006-2007) and 11 to 15 months following the commencement of the intervention (2009-2010). GEE analysis was used to examine the change in the prevalence of vegetable and fruit breaks in intervention schools compared to comparison schools. At follow-up, prevalence of vegetable and fruit breaks increased significantly in both intervention (50.3% to 82.0%, p strategy intervention can significantly increase the implementation of vegetable and fruit breaks by a large number of Australian primary schools.

  14. A primary care, electronic health record-based strategy to promote safe drug use: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Przytula, Kamila; Bailey, Stacy Cooper; Galanter, William L; Lambert, Bruce L; Shrestha, Neeha; Dickens, Carolyn; Falck, Suzanne; Wolf, Michael S

    2015-01-27

    The Northwestern University Center for Education and Research on Therapeutics (CERT), funded by the Agency for Healthcare Research and Quality, is one of seven such centers in the USA. The thematic focus of the Northwestern CERT is 'Tools for Optimizing Medication Safety.' Ensuring drug safety is essential, as many adults struggle to take medications, with estimates indicating that only half of adults take drugs as prescribed. This report describes the methods and rationale for one innovative project within the CERT: the 'Primary Care, Electronic Health Record-Based Strategy to Promote Safe and Appropriate Drug Use'. The overall objective of this 5-year study is to evaluate a health literacy-informed, electronic health record-based strategy for promoting safe and effective prescription medication use in a primary care setting. A total of 600 English and Spanish-speaking patients with diabetes will be consecutively recruited to participate in the study. Patients will be randomized to receive either usual care or the intervention; those in the intervention arm will receive a set of print materials designed to support medication use and prompt provider counseling and medication reconciliation. Participants will be interviewed in person after their index clinic visit and again one month later. Process outcomes related to intervention delivery will be recorded. A medical chart review will be performed at 6 months. Patient outcome measures include medication understanding, adherence and clinical measures (hemoglobin A1c, blood pressure, and cholesterol; exploratory outcomes only). Through this study, we will be able to examine the impact of a health literacy-informed, electronic health record-based strategy on medication understanding and adherence among diabetic primary care patients. The measurement of process outcomes will help inform how the strategy might ultimately be refined and disseminated to other sites. Strategies such as these are needed to address the

  15. Management strategies for fibromyalgia

    Directory of Open Access Journals (Sweden)

    Le Marshall KF

    2011-07-01

    Full Text Available Kim Francis Le Marshall, Geoffrey Owen LittlejohnDepartments of Rheumatology and Medicine, Monash Medical Centre and Monash University, Victoria, AustraliaDate of preparation: 14 June 2011Clinical question: What are the effective, evidence-based strategies available for the management of fibromyalgia?Conclusion: There are a number of management strategies available with robust evidence to support their use in clinical practice.Definition: Fibromyalgia is a complex pain syndrome characterized by widespread, chronic muscular pain and tenderness, disordered sleep, emotional distress, cognitive disturbance, and fatigue. Its prevalence is estimated to be 3%–5% in the population and higher yet in patients with comorbid rheumatic diseases.Level of evidence: Systematic reviews, meta-analyses, randomized controlled trials (RCTs.Search sources: PubMed, Cochrane Library, manual searchConsumer summary: Key messages for patients and clinicians are:1. There are many effective pharmacological management strategies available for fibromyalgia.2. A nonpharmacological, multicomponent approach utilizing education, aerobic exercise, psychological therapy, and other strategies is also effective for fibromyalgia.3. Despite the significant and, at times, disabling physical and psychological symptoms, fibromyalgia can be a manageable condition with a potentially good outcome.Keywords: fibromyalgia, pain, treatment, management, evidence 

  16. Personalized Search

    CERN Document Server

    AUTHOR|(SzGeCERN)749939

    2015-01-01

    As the volume of electronically available information grows, relevant items become harder to find. This work presents an approach to personalizing search results in scientific publication databases. This work focuses on re-ranking search results from existing search engines like Solr or ElasticSearch. This work also includes the development of Obelix, a new recommendation system used to re-rank search results. The project was proposed and performed at CERN, using the scientific publications available on the CERN Document Server (CDS). This work experiments with re-ranking using offline and online evaluation of users and documents in CDS. The experiments conclude that the personalized search result outperform both latest first and word similarity in terms of click position in the search result for global search in CDS.

  17. Does the incorporation of portion-control strategies in a behavioral program improve weight loss in a 1-year randomized controlled trial?

    Science.gov (United States)

    Rolls, B J; Roe, L S; James, B L; Sanchez, C E

    2017-03-01

    Controlling food portion sizes can help reduce energy intake, but the effect of different portion-control methods on weight management is not known. In a 1-year randomized trial, we tested whether the efficacy of a behavioral weight-loss program was improved by incorporating either of the two portion-control strategies instead of standard advice about eating less. The Portion-Control Strategies Trial included 186 women with obesity (81%) or overweight (19%). Participants were randomly assigned to one of three equally intensive behavioral programs, consisting of 19 individual sessions over 12 months. The Standard Advice Group was instructed to eat less food while making healthy choices, the Portion Selection Group was instructed to choose portions based on the energy density using tools such as food scales and the Pre-portioned Foods Group was instructed to structure meals around pre-portioned foods such as single-serving main dishes, for which some vouchers were provided. In an intention-to-treat analysis, a mixed-effects model compared weight loss trajectories across 23 measurements; at month 12, weight was measured for 151 participants (81%). The trajectories showed that the Pre-portioned Foods Group initially lost weight at a greater rate than the other two groups (P=0.021), but subsequently regained weight at a greater rate (P=0.0005). As a result, weight loss did not differ significantly across groups at month 6 (mean±s.e. 5.2±0.4 kg) or month 12 (4.5±0.5 kg). After 1 year, measured weight loss averaged 6% of baseline weight. The frequency of using portion-control strategies initially differed across groups, then declined over time and converged at months 6 and 12. Incorporating instruction on portion-control strategies within a 1-year behavioral program did not lead to a greater weight loss than standard advice. Using pre-portioned foods enhanced early weight loss, but this was not sustained over time. Long-term maintenance of behavioral strategies to

  18. Effectiveness of a two-step population-based osteoporosis screening program using FRAX: the randomized Risk-stratified Osteoporosis Strategy Evaluation (ROSE) study.

    Science.gov (United States)

    Rubin, K H; Rothmann, M J; Holmberg, T; Høiberg, M; Möller, S; Barkmann, R; Glüer, C C; Hermann, A P; Bech, M; Gram, J; Brixen, K

    2018-03-01

    The Risk-stratified Osteoporosis Strategy Evaluation (ROSE) study investigated the effectiveness of a two-step screening program for osteoporosis in women. We found no overall reduction in fractures from systematic screening compared to the current case-finding strategy. The group of moderate- to high-risk women, who accepted the invitation to DXA, seemed to benefit from the program. The purpose of the ROSE study was to investigate the effectiveness of a two-step population-based osteoporosis screening program using the Fracture Risk Assessment Tool (FRAX) derived from a self-administered questionnaire to select women for DXA scan. After the scanning, standard osteoporosis management according to Danish national guidelines was followed. Participants were randomized to either screening or control group, and randomization was stratified according to age and area of residence. Inclusion took place from February 2010 to November 2011. Participants received a self-administered questionnaire, and women in the screening group with a FRAX score ≥ 15% (major osteoporotic fractures) were invited to a DXA scan. Primary outcome was incident clinical fractures. Intention-to-treat analysis and two per-protocol analyses were performed. A total of 3416 fractures were observed during a median follow-up of 5 years. No significant differences were found in the intention-to-treat analyses with 34,229 women included aged 65-80 years. The per-protocol analyses showed a risk reduction in the group that underwent DXA scanning compared to women in the control group with a FRAX ≥ 15%, in regard to major osteoporotic fractures, hip fractures, and all fractures. The risk reduction was most pronounced for hip fractures (adjusted SHR 0.741, p = 0.007). Compared to an office-based case-finding strategy, the two-step systematic screening strategy had no overall effect on fracture incidence. The two-step strategy seemed, however, to be beneficial in the group of women who were

  19. Random resampling masks: a non-Bayesian one-shot strategy for noise reduction in digital holography.

    Science.gov (United States)

    Bianco, V; Paturzo, M; Memmolo, P; Finizio, A; Ferraro, P; Javidi, B

    2013-03-01

    Holographic imaging may become severely degraded by a mixture of speckle and incoherent additive noise. Bayesian approaches reduce the incoherent noise, but prior information is needed on the noise statistics. With no prior knowledge, one-shot reduction of noise is a highly desirable goal, as the recording process is simplified and made faster. Indeed, neither multiple acquisitions nor a complex setup are needed. So far, this result has been achieved at the cost of a deterministic resolution loss. Here we propose a fast non-Bayesian denoising method that avoids this trade-off by means of a numerical synthesis of a moving diffuser. In this way, only one single hologram is required as multiple uncorrelated reconstructions are provided by random complementary resampling masks. Experiments show a significant incoherent noise reduction, close to the theoretical improvement bound, resulting in image-contrast improvement. At the same time, we preserve the resolution of the unprocessed image.

  20. Implementation strategies of internet-based asthma self-management support in usual care. Study protocol for the IMPASSE cluster randomized trial.

    Science.gov (United States)

    van Gaalen, Johanna L; Bakker, Moira J; van Bodegom-Vos, Leti; Snoeck-Stroband, Jiska B; Assendelft, Willem J J; Kaptein, Ad A; van der Meer, Victor; Taube, Christian; Thoonen, Bart P; Sont, Jacob K

    2012-11-21

    Internet-based self-management (IBSM) support cost-effectively improves asthma control, asthma related quality of life, number of symptom-free days, and lung function in patients with mild to moderate persistent asthma. The current challenge is to implement IBSM in clinical practice. This study is a three-arm cluster randomized trial with a cluster pre-randomisation design and 12 months follow-up per practice comparing the following three IBSM implementation strategies: minimum strategy (MS): dissemination of the IBSM program; intermediate strategy (IS): MS + start-up support for professionals (i.e., support in selection of the appropriate population and training of professionals); and extended strategy (ES): IS + additional training and ongoing support for professionals. Because the implementation strategies (interventions) are primarily targeted at general practices, randomisation will occur at practice level.In this study, we aim to evaluate 14 primary care practices per strategy in the Leiden-The Hague region, involving 140 patients per arm. Patients aged 18 to 50 years, with a physician diagnosis of asthma, prescription of inhaled corticosteroids, and/or montelukast for ≥3 months in the previous year are eligible to participate. Primary outcome measures are the proportion of referred patients that participate in IBSM, and the proportion of patients that have clinically relevant improvement in the asthma-related quality of life. The secondary effect measures are clinical outcomes (asthma control, lung function, usage of airway treatment, and presence of exacerbations); self-management related outcomes (health education impact, medication adherence, and illness perceptions); and patient utilities. Process measures are the proportion of practices that participate in IBSM and adherence of professionals to implementation strategies. Cost-effective measurements are medical costs and healthcare consumption. Follow-up is six months per patient. This study

  1. Implementation strategies of internet-based asthma self-management support in usual care. Study protocol for the IMPASSE cluster randomized trial

    Directory of Open Access Journals (Sweden)

    van Gaalen Johanna L

    2012-11-01

    Full Text Available Abstract Background Internet-based self-management (IBSM support cost-effectively improves asthma control, asthma related quality of life, number of symptom-free days, and lung function in patients with mild to moderate persistent asthma. The current challenge is to implement IBSM in clinical practice. Methods/design This study is a three-arm cluster randomized trial with a cluster pre-randomisation design and 12 months follow-up per practice comparing the following three IBSM implementation strategies: minimum strategy (MS: dissemination of the IBSM program; intermediate strategy (IS: MS + start-up support for professionals (i.e., support in selection of the appropriate population and training of professionals; and extended strategy (ES: IS + additional training and ongoing support for professionals. Because the implementation strategies (interventions are primarily targeted at general practices, randomisation will occur at practice level. In this study, we aim to evaluate 14 primary care practices per strategy in the Leiden-The Hague region, involving 140 patients per arm. Patients aged 18 to 50 years, with a physician diagnosis of asthma, prescription of inhaled corticosteroids, and/or montelukast for ≥3 months in the previous year are eligible to participate. Primary outcome measures are the proportion of referred patients that participate in IBSM, and the proportion of patients that have clinically relevant improvement in the asthma-related quality of life. The secondary effect measures are clinical outcomes (asthma control, lung function, usage of airway treatment, and presence of exacerbations; self-management related outcomes (health education impact, medication adherence, and illness perceptions; and patient utilities. Process measures are the proportion of practices that participate in IBSM and adherence of professionals to implementation strategies. Cost-effective measurements are medical costs and healthcare consumption

  2. Varied Search Protocols Lead to Clinically Relevant Results. A review of: Patel, Manesh R., Connie M. Schardt, Linda L. Sanders, and Sheri A. Keitz. “Randomized Trial for Answers to Clinical Questions: Evaluating a Pre‐Appraised Versus a MEDLINE Search Protocol.” Journal of the Medical Library Association 94.4 (2006: 382‐6.

    Directory of Open Access Journals (Sweden)

    Marcy L. Brown

    2008-03-01

    Full Text Available Objective – To determine the success rate of electronic resources for answering clinical questions by comparing speed, validity, and applicability of two different protocols for searching the medical literature.Design – Randomized trial with results judged by blinded panel.Setting – Duke University Medical Center in Durham, North Carolina, United States ofAmerica.Subjects – Thirty‐two 2nd and 3rd year internal medicine residents on an eight week general medicine rotation at the Duke University Medical Center.Methods – Two search protocols were developed:Protocol A: Participants searched MEDLINE first, and then searched pre‐appraised resources if needed.Protocol B: Participants searched pre‐appraised resources first, which included UpToDate, ACP JournalClub, Cochrane Database of Systematic Reviews, and DARE. The residents then searched MEDLINE if an answer could not be found in the 66 initial group of pre‐appraised resources. Residents were randomised by computer-assisted block order into four blocks of eight residents each. Two blocks were assigned to Protocol A, and two to Protocol B. Each day, residents developed at least one clinical question related to caring for patients. The questions were transcribed onto pocket-sized cards, with the answer sought later using the assigned protocol. If answers weren’t found using either protocol, searches were permitted in other available resources. When an article that answered a question was found, the resident recorded basic information about the question and the answer as well as the time required to find the answer (less than five minutes; between five and ten minutes; or more than ten minutes. Residents were to select answers that were “methodologically sound and clinically important” (384. Ten faculty members formally trained in evidence‐based medicine (EBM reviewed a subset of therapy‐related questions and answers. The reviewers, who were blinded to the search protocols

  3. Enhancing outreach for persons with serious mental illness: 12-month results from a cluster randomized trial of an adaptive implementation strategy.

    Science.gov (United States)

    Kilbourne, Amy M; Almirall, Daniel; Goodrich, David E; Lai, Zongshan; Abraham, Kristen M; Nord, Kristina M; Bowersox, Nicholas W

    2014-12-28

    Few implementation strategies have been empirically tested for their effectiveness in improving uptake of evidence-based treatments or programs. This study compared the effectiveness of an immediate versus delayed enhanced implementation strategy (Enhanced Replicating Effective Programs (REP)) for providers at Veterans Health Administration (VA) outpatient facilities (sites) on improved uptake of an outreach program (Re-Engage) among sites not initially responding to a standard implementation strategy. One mental health provider from each U.S. VA site (N = 158) was initially given a REP-based package and training program in Re-Engage. The Re-Engage program involved giving each site provider a list of patients with serious mental illness who had not been seen at their facility for at least a year, requesting that providers contact these patients, assessing patient clinical status, and where appropriate, facilitating appointments to VA health services. At month 6, sites considered non-responsive (N = 89, total of 3,075 patients), defined as providers updating documentation for less than implementation interventions: Enhanced REP (provider coaching; N = 40 sites) for 6 months followed by Standard REP for 6 months; versus continued Standard REP (N = 49 sites) for 6 months followed by 6 months of Enhanced REP for sites still not responding. Outcomes included patient-level Re-Engage implementation and utilization. Patients from sites that were randomized to receive Enhanced REP immediately compared to Standard REP were more likely to have a completed contact (adjusted OR = 2.13; 95% CI: 1.09-4.19, P = 0.02). There were no differences in patient-level utilization between Enhanced and Standard REP sites. Enhanced REP was associated with greater Re-Engage program uptake (completed contacts) among sites not responding to a standard implementation strategy. Further research is needed to determine whether national implementation of Facilitation results

  4. Blood transfusion strategy and risk of postoperative delirium in nursing homes residents with hip fracture. A post hoc analysis based on the TRIFE randomized controlled trial.

    Science.gov (United States)

    Blandfort, Sif; Gregersen, Merete; Borris, Lars Carl; Damsgaard, Else Marie

    2017-06-01

    To investigate whether a liberal blood transfusion strategy [Hb levels ≥11.3 g/dL (7 mmol/L)] reduces the risk of postoperative delirium (POD) on day 10, among nursing home residents with hip fracture, compared to a restrictive transfusion strategy [Hb levels ≥9.7 g/dL (6 mmol/L)]. Furthermore, to investigate whether POD influences mortality within 90 days after hip surgery. This is a post hoc analysis based on The TRIFE - a randomized controlled trial. Frail anemic patients from the Orthopedic Surgical Ward at Aarhus University Hospital were enrolled consecutively between January 18, 2010 and June 6, 2013. These patients (aged ≥65 years) had been admitted from nursing homes for unilateral hip fracture surgery. After surgery, 179 patients were included in this study. On the first day of hospitalization, all enrolled patients were examined for cognitive impairment (assessed by MMSE) and delirium (assessed by CAM). Delirium was also assessed on the tenth postoperative day. The prevalence of delirium was 10 % in patients allocated to a liberal blood transfusion strategy (LB) and 21 % in the group with a restrictive blood transfusion strategy (RB). LB prevents development of delirium on day 10, compared to RB, odds ratio 0.41 (95 % CI 0.17-0.96), p = 0.04. Development of POD on day 10 increased the risk of 90-day death, hazard ratio 3.14 (95 % CI 1.72-5.78), p < 0.001. In nursing home residents undergoing surgery for hip fracture, maintaining hemoglobin level above 11.3 g/dL reduces the rate of POD on day 10 compared to a RB. Development of POD is associated with increased mortality.

  5. A Randomized Controlled Trial to Evaluate a Potential Hepatitis B Booster Vaccination Strategy Using Combined Hepatitis A and B Vaccine.

    Science.gov (United States)

    Li, Fangjun; Hu, Yuansheng; Zhou, Youming; Chen, Lixin; Xia, Wei; Song, Yufei; Tan, Zhengliang; Gao, Lidong; Yang, Zhong; Zeng, Gang; Han, Xing; Li, Junhua; Li, Jing

    2017-05-01

    Booster doses could play a major role in no responders or low responders to primary hepatitis B (HB) vaccine. Planed time point for hepatitis A vaccination in China provides a good opportunity to carry out HB booster dose by using combined hepatitis A and B vaccine. A randomized, double-blinded clinical trial was conducted to compare the immunogenicity and safety of toddlers 18-24 months of age receiving 3 different vaccination regimens: 2 doses of inactivated hepatitis A vaccine (group 1), 1 dose of inactivated hepatitis A vaccine plus 1 dose of combined hepatitis A and B vaccine (group 2) or 2 doses of combined hepatitis A and B vaccine (group 3). All 3 groups showed 100% seroprotection for antihepatitis A virus antibody after vaccination. Seroprotection rate for anti-HB antibody before vaccination ranged from 79.5% to 92.9% in the 3 groups. After second inoculation, anti-HBs seroprotection increased from 92.9% to 100% in group 2 with postvaccination geometric mean concentration (GMC) of 2258.3 mIU/mL and from 79.5% to 98.9% in group 3 with postvaccination GMC of 2055.3 mIU/mL. The adverse events were not statistically different among groups (P = 0.345). Combined hepatitis A and B vaccine could stimulate high level of both antihepatitis A virus and anti-HBs antibodies and not increase adverse events, providing a new choice for HB booster.

  6. Neural-Fuzzy Digital Strategy of Continuous-Time Nonlinear Systems Using Adaptive Prediction and Random-Local-Optimization Design

    Directory of Open Access Journals (Sweden)

    Zhi-Ren Tsai

    2013-01-01

    Full Text Available A tracking problem, time-delay, uncertainty and stability analysis of a predictive control system are considered. The predictive control design is based on the input and output of neural plant model (NPM, and a recursive fuzzy predictive tracker has scaling factors which limit the value zone of measured data and cause the tuned parameters to converge to obtain a robust control performance. To improve the further control performance, the proposed random-local-optimization design (RLO for a model/controller uses offline initialization to obtain a near global optimal model/controller. Other issues are the considerations of modeling error, input-delay, sampling distortion, cost, greater flexibility, and highly reliable digital products of the model-based controller for the continuous-time (CT nonlinear system. They are solved by a recommended two-stage control design with the first-stage (offline RLO and second-stage (online adaptive steps. A theorizing method is then put forward to replace the sensitivity calculation, which reduces the calculation of Jacobin matrices of the back-propagation (BP method. Finally, the feedforward input of reference signals helps the digital fuzzy controller improve the control performance, and the technique works to control the CT systems precisely.

  7. Adding evidence-based behavioral weight loss strategies to a statewide wellness campaign: a randomized clinical trial.

    Science.gov (United States)

    Leahey, Tricia M; Thomas, Graham; Fava, Joseph L; Subak, Leslee L; Schembri, Michael; Krupel, Katie; Kumar, Rajiv; Weinberg, Brad; Wing, Rena R

    2014-07-01

    We determined the efficacy and cost-effectiveness of adding an evidence-based Internet behavioral weight loss intervention alone or combined with optional group sessions to ShapeUp Rhode Island 2011 (SURI), a 3-month statewide wellness campaign. We randomized participants (n = 230; body mass index = 34.3 ±6.8 kg/m(2); 84% female) to the standard SURI program (S) or to 1 of 2 enhanced programs: SURI plus Internet behavioral program (SI) or SI plus optional group sessions (SIG). The primary outcome was weight loss at the end of the 3-month program. Weight losses differed among all 3 conditions (S: 1.1% ±0.9%; SI: 4.2% ±0.6%; SIG: 6.1% ±0.6%; Ps ≤ .04). Both SI and SIG increased the percentage of individuals who achieved a 5% weight loss (SI: 42%; SIG: 54%; S: 7%; Ps < .001). Cost per kilogram of weight loss was similar for S ($39) and SI ($35); both were lower than SIG ($114). Although weight losses were greatest at the end of SURI with optional group sessions, the addition of an Internet behavioral program was the most cost-effective method to enhance weight losses.

  8. Neck-Related Physical Function, Self-Efficacy, and Coping Strategies in Patients With Cervical Radiculopathy: A Randomized Clinical Trial of Postoperative Physiotherapy.

    Science.gov (United States)

    Wibault, Johanna; Öberg, Birgitta; Dedering, Åsa; Löfgren, Håkan; Zsigmond, Peter; Persson, Liselott; Andell, Maria; R Jonsson, Margareta; Peolsson, Anneli

    2017-06-01

    The purpose of this study was to compare postoperative rehabilitation with structured physiotherapy to the standard approach in patients with cervical radiculopathy (CR) in a prospective randomized study at 6 months follow-up based on measures of neck-related physical function, self-efficacy, and coping strategies. Patients with persistent CR and scheduled for surgery (N = 202) were randomly assigned to structured postoperative physiotherapy or a standard postoperative approach. Structured postoperative physiotherapy combined neck-specific exercises with a behavioral approach. Baseline, 3-month, and 6-month evaluations included questionnaires and clinical examinations. Neck muscle endurance, active cervical range of motion, self-efficacy, pain catastrophizing (CSQ-CAT), perceived control over pain, and ability to decrease pain were analyzed for between-group differences using complete case and per-protocol approaches. No between-group difference was reported at the 6-month follow-up (P = .05-.99), but all outcomes had improved from baseline (P physiotherapy with ≥50% attendance at treatment sessions had larger improvements in CSQ-CAT (P = .04) during the rehabilitation period from 3 to 6 months after surgery compared with the patients who received standard postoperative approach. No between-group difference was found at 6 months after surgery based on measures of neck-related physical function, self-efficacy, and coping strategies. However, the results confirm that neck-specific exercises are tolerated by patients with CR after surgery and may suggest a benefit from combining surgery with structured postoperative physiotherapy for patients with CR. Copyright © 2017. Published by Elsevier Inc.

  9. 'Doctor Google' ending the diagnostic odyssey in lysosomal storage disorders: parents using internet search engines as an efficient diagnostic strategy in rare diseases

    NARCIS (Netherlands)

    Bouwman, M.G.; Teunissen, Q.G.A.; Wijburg, F.A.; Linthorst, G.E.

    2010-01-01

    The expansion of the internet has resulted in widespread availability of medical information for both patients and physicians. People increasingly spend time on the internet searching for an explanation, diagnosis or treatment for their symptoms. Regarding rare diseases, the use of the internet may

  10. Motor learning strategies in basketball players and its implications for ACL injury prevention: a randomized controlled trial.

    Science.gov (United States)

    Benjaminse, Anne; Otten, Bert; Gokeler, Alli; Diercks, Ron L; Lemmink, Koen A P M

    2017-08-01

    Adding external focus of attention (EF, focus on the movement effect) may optimize current anterior cruciate ligament (ACL) injury prevention programmes. The purpose of the current study was to investigate the effects of an EF, by a visual stimulus and an internal focus, by a verbal stimulus during unexpected sidestep cutting in female and male athletes and how these effects remained over time. Ninety experienced basketball athletes performed sidestep cutting manoeuvres in three sessions (S1, S2 and S3). In this randomized controlled trial, athletes were allocated to three groups: visual (VIS), verbal (VER) and control (CTRL). Kinematics and kinetics were collected at the time of peak knee frontal plane moment. Males in the VIS group showed a larger vertical ground reaction force (S1: 25.4 ± 3.1 N/kg, S2: 25.8 ± 2.9 N/kg, S3: 25.2 ± 3.2 N/kg) and knee flexion moments (S1: -3.8 ± 0.9 Nm/kg, S2: -4.0 ± 1.2 Nm/kg, S3: -3.9 ± 1.3 Nm/kg) compared to the males in the VER and CTRL groups and to the females in the VIS group (p knee valgus moment and the females in the VER group reduced knee varus moment over time (n.s.). Male subjects clearly benefit from visual feedback. Females may need different feedback modes to learn a correct movement pattern. Sex-specific learning preferences may have to be acknowledged in day by day practice. Adding video instruction or feedback to regular training regimens when teaching athletes safe movement patterns and providing individual feedback might target suboptimal long-term results and optimize ACL injury prevention programmes. I.

  11. Renal function following three distinct weight loss dietary strategies during 2 years of a randomized controlled trial.

    Science.gov (United States)

    Tirosh, Amir; Golan, Rachel; Harman-Boehm, Ilana; Henkin, Yaakov; Schwarzfuchs, Dan; Rudich, Assaf; Kovsan, Julia; Fiedler, Georg M; Blüher, Matthias; Stumvoll, Michael; Thiery, Joachim; Stampfer, Meir J; Shai, Iris

    2013-08-01

    This study addressed the long-term effect of various diets, particularly low-carbohydrate high-protein, on renal function on participants with or without type 2 diabetes. In the 2-year Dietary Intervention Randomized Controlled Trial (DIRECT), 318 participants (age, 51 years; 86% men; BMI, 31 kg/m(2); mean estimated glomerular filtration rate [eGFR], 70.5 mL/min/1.73 m(2); mean urine microalbumin-to-creatinine ratio, 12:12) with serum creatinine low-fat, Mediterranean, or low-carbohydrate diets. The 2-year compliance was 85%, and the proportion of protein intake significantly increased to 22% of energy only in the low-carbohydrate diet (P vs. low-fat and Mediterranean). We examined changes in urinary microalbumin and eGFR, estimated by Modification of Diet in Renal Disease and Chronic Kidney Disease Epidemiology Collaboration formulas. Significant (P low-carbohydrate (+5.3% [95% CI 2.1-8.5]), Mediterranean (+5.2% [3.0-7.4]), and low-fat diets (+4.0% [0.9-7.1]) with similar magnitude (P > 0.05) across diet groups. The increased eGFR was at least as prominent in participants with (+6.7%) or without (+4.5%) type 2 diabetes or those with lower baseline renal function of eGFR low-carbohydrate diet is as safe as Mediterranean or low-fat diets in preserving/improving renal function among moderately obese participants with or without type 2 diabetes, with baseline serum creatinine <176 μmol/L. Potential improvement is likely to be mediated by weight loss-induced improvements in insulin sensitivity and blood pressure.

  12. E-learning interventions are comparable to user's manual in a randomized trial of training strategies for the AGREE II

    Directory of Open Access Journals (Sweden)

    Durocher Lisa D

    2011-07-01

    Full Text Available Abstract Background Practice guidelines (PGs are systematically developed statements intended to assist in patient and practitioner decisions. The AGREE II is the revised tool for PG development, reporting, and evaluation, comprised of 23 items, two global rating scores, and a new User's Manual. In this study, we sought to develop, execute, and evaluate the impact of two internet interventions designed to accelerate the capacity of stakeholders to use the AGREE II. Methods Participants were randomized to one of three training conditions. 'Tutorial'--participants proceeded through the online tutorial with a virtual coach and reviewed a PDF copy of the AGREE II. 'Tutorial + Practice Exercise'--in addition to the Tutorial, participants also appraised a 'practice' PG. For the practice PG appraisal, participants received feedback on how their scores compared to expert norms and formative feedback if scores fell outside the predefined range. 'AGREE II User's Manual PDF (control condition'--participants reviewed a PDF copy of the AGREE II only. All participants evaluated a test PG using the AGREE II. Outcomes of interest were learners' performance, satisfaction, self-efficacy, mental effort, time-on-task, and perceptions of AGREE II. Results No differences emerged between training conditions on any of the outcome measures. Conclusions We believe these results can be explained by better than anticipated performance of the AGREE II PDF materials (control condition or the participants' level of health methodology and PG experience rather than the failure of the online training interventions. Some data suggest the online tools may be useful for trainees new to this field; however, this requires further study.

  13. Simultaneous escaping of explicit and hidden free energy barriers: application of the orthogonal space random walk strategy in generalized ensemble based conformational sampling.

    Science.gov (United States)

    Zheng, Lianqing; Chen, Mengen; Yang, Wei

    2009-06-21

    To overcome the pseudoergodicity problem, conformational sampling can be accelerated via generalized ensemble methods, e.g., through the realization of random walks along prechosen collective variables, such as spatial order parameters, energy scaling parameters, or even system temperatures or pressures, etc. As usually observed, in generalized ensemble simulations, hidden barriers are likely to exist in the space perpendicular to the collective variable direction and these residual free energy barriers could greatly abolish the sampling efficiency. This sampling issue is particularly severe when the collective variable is defined in a low-dimension subset of the target system; then the "Hamiltonian lagging" problem, which reveals the fact that necessary structural relaxation falls behind the move of the collective variable, may be likely to occur. To overcome this problem in equilibrium conformational sampling, we adopted the orthogonal space random walk (OSRW) strategy, which was originally developed in the context of free energy simulation [L. Zheng, M. Chen, and W. Yang, Proc. Natl. Acad. Sci. U.S.A. 105, 20227 (2008)]. Thereby, generalized ensemble simulations can simultaneously escape both the explicit barriers along the collective variable direction and the hidden barriers that are strongly coupled with the collective variable move. As demonstrated in our model studies, the present OSRW based generalized ensemble treatments show improved sampling capability over the corresponding classical generalized ensemble treatments.

  14. Design considerations of a randomized controlled trial of sedation level during hip fracture repair surgery: a strategy to reduce the incidence of postoperative delirium in elderly patients.

    Science.gov (United States)

    Li, Tianjing; Wieland